Declination compensation in seismic survey

FIELD: physics.

SUBSTANCE: in seismic survey in icy water, streamers are towed behind a vessel under the water surface to avoid collision with ice. GPS readings may not be consistently obtained because the ice prevents a tail buoy with a GPS receiver from trailing from the streamer on the surface Instead, a device is towed on the streamer under the water surface. The absolute position of the streamer is tracked by intermittently bringing the towed device towards the surface so that GPS readings can be obtained. The absolute position of the streamer can then be used in conjunction with compass readings and can correlate various seismic sensor signals obtained along the streamer during the survey. The compass readings can be corrected for declination using declinometer readings, which can be compensated for iron effects from the vessel or other device carrying the declinometer.

EFFECT: high accuracy of survey data.

31 cl, 33 dwg

 

CROSS-REFERENCE TO RELATED APPLICATIONS

[001] this application that is a continuation of application No. 12/719783 on U.S. patent, filed on March 8, 2010, the priority of said application are incorporated into this application by reference, the priority of which is, in turn, is requested in accordance with the provisional patent applications U.S. No. 61/158698, filed March 9, 2009, No. 61/246367, filed September 28, 2009 and No. 61/261329, filed November 14, 2009.

PREREQUISITES

[002] In conventional seismic exploration using seismic source and some towed KOs, towed behind the seismic vessel. These towed spit have sensors that detected seismic energy to build the image layers below the seafloor. The release of KOs and towed sources and towing them in the process of exploration experience no difficulties when working in free from the ice waters with moderate agitation or in similar situations.

[003] However, in the sea areas covered by ice, debris, in the presence of large waves or other obstacles intelligence may become more difficult, expensive or even impossible. For example, in ice-covered waters of the seismic vessel should pave the way in the ice and maneuver in waters filled with rubble ice fields. The noise beats l�Yes, also can complicate the received seismic record.

[004] In addition, the icy debris field on the surface of the water makes the towing of the source and towed KOs more difficult and predispose to injury. For example, any of the components of the system on the surface water can run into the ice, take the ice and be lost. In addition, on the surface of any cables or tow ropes manufactured from the vessel, even with the slips, you may become ice, potentially damaging the cables or tow ropes. Moreover, ice, tighten under the housing and pop-up behind the ship, can move these cables. Some methods of performing seismic surveys in ice-covered areas are known in the art and are disclosed in U.S. patents Nos. 5113376 and 5157636 (Bjerkoy). To date, however, the problems associated with marine seismic exploration in the ice-covered or having obstacles waters is not permitted.

[005] for Example, in addition to some physical problems, occurring in Arctic or ice-covered areas, variations of earth's magnetic field in any particular area of land can create problems in land and marine seismic exploration. As you know, the earth's magnetic field can be described by seven parameters, including the declination (D), inclination (I), the horizontal�sexual tension (N) fields North (X) and East (Y) components of the horizontal field intensity, vertical intensity (Z) of the field, full tension (F) of the field, measured in units of nanotesla. A large part of the geomagnetic field (main field) comes from the outer part of the earth's core. Various mathematical models, such as the international geomagnetic reference field (MAGP) and world magnetic model (AMM), it is possible to describe the main field and slow change over time. Although the changes in the field can be to some extent predictable, the geomagnetic field also changes due to currents inside the magnetosphere and ionosphere and due to other changes that are less predictable.

[006] Variations and changes of the geomagnetic field can affect seismic exploration in Arctic regions, and also in other places. For example, the readings on the compass with the equipment seismic surveys may be influenced by differences in the decline in Arctic latitudes. As is known, the magnetic declination is the angle between magnetic North and true geographic North. The variation of the declination depends on the latitude and longitude and change over time, and the variability of the azimuth increases in Arctic latitudes.

[007] As will be understood, the location of the compass reading on the compass mo�but adjust based on the magnetic declination (the angle between true North and the horizontal line of the magnetic field). To adjust the compass bearing, true bearing is calculated by adding the magnetic declination to the compass the magnetic bearing. Unfortunately, in areas near the North and South magnetic poles may be erroneous or unusable readings on the compass, and in some areas of the earth there can be huge differences of declination.

[008] Published magnetic models of the earth invariably inherent error or lack of accuracy, in order to achieve the level of detail needed in some cases. In conventional marine seismic exploration, you can eliminate the problem by using a traverse loop, which counts the signals of global positioning system (GPS readings) to receive on tail buoys following the towed spits. However, exploration in the Arctic conditions in the system usually cannot use tail buoy because of the presence of the debris fields of ice, so the system cannot get the GPS readings on a reliable basis. This makes more difficult the tracking of the location of the equipment, seismic survey and receiving data in waters with ice and obstacles.

[009] the present disclosure aims to exclude or at least reduce the influence of the problems set forth above.

SUMMARY/p>

[010] the Seismic system is operated in areas or time periods with variations of the declination, which can cause measurement errors of the geomagnetic field by the process of exploration. For example, in the Arctic regions of the earth, there can be a variation of the declination, which can change in the area of seismic exploration, and error counts on compasses can create problems in marine seismic exploration in such areas. The problem can be further exacerbated when the district has some ice water, which is limited to the use of tail buoys to obtain samples for signals of a global positioning system (GPS readings).

[011] for Example, in the marine system in the process of exploration of the towed spit towed vessel. With compasses collect information to calculate the locations of the towed KOs in the process of marine seismic exploration. As you know, the compass is provided a magnetic azimuth, and their location is calculated in a geographic coordinate system. Because compasses are sensitive to the local magnetic field declination at any local discrepancies may decrease the accuracy of the reconstruction provisions towed KOs on the basis of readings on the compass. For this reason, in the exploration system magnetic declination is measured in real time � continued exploration, and measurements of the geomagnetic field (e.g., readings on the compass) adjusting in real time, or later during processing.

[012] the Correction for declination can be useful in marine seismic prospecting of any kind, and even in land seismic exploration. In particular, in marine research in the Arctic areas of correction for magnetic declination can be particularly useful because the system is not always possible to use the GPS readings with tail buoys or similar towed on spits to determine the location of the sensors. Instead, towed spits a cable compasses or other magnetic exchange instruments used for monitoring the position of the towed KOs in the process of exploration. So you can adjust the readings on the compass wealthy without GPS samples from the tail buoy, the exploration system is determined by the change of the current magnetic declination caused by variations in the earth's crust, atmosphere, etc.

[013] As noted above, in Arctic exploration areas in the system usually cannot use tail buoys to obtain absolute positions (e.g., GPS readings) trailed CBS because of the presence of the debris fields of ice, and other obstacles. Therefore, when exploring, you should use open-loop course. Therefore, the reason in the system to be strictly correct the error counts on various compasses all over towed KOs. As a solutions-driven apparatus to the towed streamers can sometimes lead to the surface in the absence of the debris fields of ice or other obstacles to absolute position (e.g., GPS readings) it was possible to receive and transmit in the exploration system. Such driven apparatus can be positioned in the rear of the towed KOs or anywhere else.

[014] After receiving the GPS readings on a periodic basis operated vehicle can dive back under the surface to avoid collision with ice and to maintain the protected towed spit below the water surface. At this time, information about the relative position of the device with inertial navigation systems (ins), integrated navigation system or other similar system may be added to receive periodic GPS readings, so that the position of the towed KOs can be determined even in the case where significant debris fields of ice on the surface exclude the acquisition of new GPS readings on managed devices. This information about the relative position includes inertial measurements for the towed spit, submerged below the water surface.

[015] in Addition, in the exploration system can be obtained measuring the declination and adjusted accordingly countdown� different cable compasses and other sensors on towed streamers. To enable this, the declinometer, having a magnetometer, can be deployed behind the vessel to obtain measurements of the declination. For example, declinometer may be towed at the cable end of the towed spit or be towed astern of the vessel. Typically, such a declinometer towed behind the towing ship at the distance of two or more of the vessel's length.

[016] In some declinometer due to problems related to the movement of the declinometer when towing, maybe overly complicated processing measurements obtained by the declinometer. For example, you may need correction on a continuous basis to the reference magnetometer depending on the spatial orientation of the towed magnetometer. This may increase the computational complexity. To avoid this complexity components of the declinometer can be used directly on the towing vessel, even if the ship has a magnetic influence on the readings of the declination. The use of the vessel is possible when the different stages of calibration is performed to compensate the effects of magnetically soft and magnetically hard iron induced vessel on declinometer.

[017] With the declinometer intended for use on the ship, get counts three components of the geomagnetic field using the magnetometer,such as air navigation strapdown 24-bit magnetometer Honeywell. In the declinometer is also used techcompany block device inertial measurements (Biya) in addition to the calculations for compensation of motion in relation to this device. Finally, in the system are combined with each other GPS timing and inertial measurement (i.e., the absolute position and the position from the inertial unit) and then the measurements are compared to the count of three components of the geomagnetic field with the magnetometer to calculate the corrections for declination. In turn, the counts of different cable compasses and other sensors throughout the towed KOs can be adjusted with this in mind, the calculated declination.

[018] the correction for the declination as determined by the towing vessel, can be used in marine seismic surveys in waters with ice or obstacles, as well as in other applications. In General, the methods disclosed in this application, you can apply for Maritime intelligence, when the tail buoy cannot be used to obtain GPS readings or when such samples can only be obtained from time to time. For example, in the case of marine seismic surveys any type that uses the towed spit, towed at great depth or at an angle relative to the towing ship, so getting GPS readings for towed KOs becomes impossible, can� to benefit from these methods.

[019] As noted above, when using the measurement of the declination from the towing vessel for correction of the samples cable compasses on towed spits you must perform the calibration steps to account for the influence of the declinometer. Briefly, when the towing vessel is on a circular route, in the calibration process receive samples from the declinometer and the instrument unit inertial navigation. Then the readings from the inertial navigation device used for correction of the angle of pitch and roll of the towing vessel. After this exploration in the system are corrected for the effects of magnetic solid iron from the towing ship and the effects of magnetic soft iron because of the differences between the ambient magnetic field of the earth on the ship. With the help of a software-implemented algorithms perform these adjustments and determine correction factors or parameters. In addition, the deflection curve can be used to monitor the magnetic field, and geomagnetic Observatory data in areas of interest can be used to improve the calibration of the declinometer.

[020] the Obtained corrections for declination can be applied to samples from any of various instruments used in the process of seismic exploration, such as cable compasses, towed spit, etc. Different counts can be corrected in realhomemade, and the original data to correct for inclination and correction of the samples on the compasses can be saved for subsequent use and processing. Also, the counts for compasses and similar can be corrected in real time, so that the exploration system can better monitor and regulate towed KOs in the process of exploration.

[021] it is considered that the amendments on the latitudes of the Arctic regions can be from 1 to 2°. When the system includes numerous towed spit, having considerable extent, variations in length of the towed KOs can be exacerbated in the process of exploration. Therefore, the possibility of correcting the error of the declination may be useful in the monitoring and registration provisions of the towed KOs in the process of seismic exploration. Finally, when using the correction can be obtained an accuracy approaching 0.1 percent.

[022] In contrast to marine applications declination variations can create a problem at ground applications where the use of a magnetic directional angle. Declination varies in space and time, and the variations may be amplified in the Arctic latitudes during solar storms, etc. Therefore, even when terrestrial intelligence may be received benefit from the disclosed methods.

[023] the above summary is not predpolagaetsya every possible variant of implementation, or any aspect of the present disclosure.

BRIEF description of the DRAWINGS

IN the DRAWINGS:

[024] Fig. 1 - illustration of the correction process for inducing seismic signals intelligence;

[025] Fig. 2A-2B - types on the side and in terms of the marine seismic system in accordance with certain ideas of the present disclosure intended for use in ice-covered areas;

[026] Fig. 2C-2D - kinds of the side of the marine seismic system having a floating device and controlled devices of different types;

[027] Fig. 3A-3B illustrate a controllable device of the same species in two operating conditions;

[028] Fig. 4 - view of the managed device according to the embodiment of the present disclosure;

[029] Fig. 5 is an illustration of internal parts and components of the managed device;

[030] Fig. 6A is a side view of the marine seismic system having a remotely operated towed vehicle (OAK) as a managed device in the rear part of the towing KOs;

[031] Fig. 6B is a plan view of another marine seismic system having a remotely operated towed apparatus on the towing KOs;

[032] Fig. 7A-7B is a more detailed types of remotely operated towed apparatus (OAK);

[033] Fig. 8 is a structural diagram of a management system designed to control remotely control�aamah towed vehicles and for determining the locations of their reckoning of the way when towing;

[034] Fig. 9 is an illustration of a control loop for the number of ways and correction of a drift in the inertial navigation system in relation to the towed machine;

[035] Fig. 10 is an illustration of the towed spit with the location of sensors designed to determine the shape of the towed spit when using a GPS reference for the vessel, known sensor locations known location of the managed device and counts on various compasses;

[036] Fig. 11 is an illustration of various configurations of the acoustic systems in the implementation of acoustic crosstalk for positioning a towed KOs;

[037] Fig. 12A-12B is a schematic illustration of elements of control system on the towing vessel, having components of the declinometer;

[038] Fig. 12C is a schematic illustration of the geomagnetic coordinate system;

[039] Fig. 12D is a schematic illustration of the coordinate system of the vessel with the spatial position angle, measured relative to true North and the horizontal plane;

[040] Fig. 13 is a General block diagram of the sequence of actions for seismic exploration using the declination determined by the Board;

[041] Fig. 14 is a block diagram of the sequence of actions of the calibration process in the determination of the declination on the towing vessel;

[042] Fig. 15A-15B illustration dvuhchelyustnyh routes of the vessel;

[043] Fig. 16A-16B is a more detailed illustration of the calibration process;

[044] Fig. 16C is a schematic illustration of the interpolation of the declination for the area of exploration based on the declination of base stations;

[045] Fig. 17 is a graphical illustration of stages intended for finding the rotated vertical component (Mz) magnetometer as a function of azimuth based on the GPS readings/readings unit inertial measurement when using the deflection curve of the fourth order Fourier series and least squares method;

[046] Fig. 18 is a graphic illustration of the stages designed for the simultaneous finding the parameters of the horizontal components (Mx, My) magnetometer using the least squares method to implement compensation for the effect of magnetically hard and magnetically soft iron in a horizontal plane;

[047] Fig. 19 is a graphical illustration of steps designed to determine the weighted interpolated curves Delta-declination for location calibration;

[048] Fig. 20 is a block diagram of the sequence of actions when performing the processing steps designed to correct for the influence of the declination readings on cable compasses in marine seismic exploration; and

[041] Fig. 21 is a schematic illustration of a land seismic exploration system according to this disclosed�Yu.

DETAILED DESCRIPTION

A. CORRECTION FOR DECLINATION IN SEISMIC PROSPECTING

[050] In seismic prospecting on land or sea use sensors for receiving seismic signals. In such cases, the image of interest underground reservoir can be formed when receiving seismic signals of the location of these sensors is known. In many cases, measurements of the geomagnetic field, such as the readings on the compasses, used to determine the location, orientation, and rate of seismic sensors. Although the declination changes over time and in different places on earth, the change may be more pronounced in certain places (e.g. in the Arctic) or during certain events (for example, solar storms). Therefore, the possibility of correcting for declination in real time for a given spatial location on earth can be useful in seismic exploration and can improve the accuracy of exploration results.

[051] In this disclosed system and method for correcting for declination in time and space in the process of seismic exploration, which can be land or sea. Figure 1 shows a block diagram of a workflow process 10 correction for declination during seismic surveys. In the process of exploration �assicheskie receive signals (block 12) in the exploration area by using one or more seismic sensors. In the case of naval intelligence sensors may be hydrophones, spaced throughout the towed KOs, towed behind the vessel, and seismic signals can be generated by sources such as air guns towed behind the vessel. In the case of ground surveillance sensors may be geophones, spaced at different locations on the soil, and seismic signals can be generated by a vibrator or other seismic source.

[052] To construct the image of interest of a formation using seismic signals must be known the position of the sensors relative to the source. To do this, get (block 14) measurements of the local geomagnetic field related to seismic sensors. For example, the readings on the compass you can do on a towed spits in the process of marine seismic exploration. In addition, the counts can be done on the towing vessel or in other places. In the case of surface seismic readings on the compass can also be obtained to perform the orientation of the sensors and sources.

[053] As is known, compasses and other similar sensors given magnetic azimuth, but the provisions of the various sensors, sources, etc., necessary to construct the image of the geological environment, is calculated in the system of geographical coordinates such as latitude and d�Lhota. Therefore, the readings on the compass must be translated into a coordinate system. Unfortunately, compasses or similar sensors are sensitive to the local magnetic field declination in the area of intelligence, so that when any local mismatch decreases the accuracy of the reconstructed locations of compasses. To avoid this, measurements of the local geomagnetic field adjusted to account for the declination in the area of intelligence.

[054] the Declination varies over time and over individual plots of land. As noted earlier, this may be especially pronounced in certain areas or under certain conditions. Therefore, measurements of the local geomagnetic field (i.e., the readings on the compass) correct (blocks 16-17) on the basis of temporal and spatial parameters of the declination, which is determined in accordance with the methods discussed in this application. Ultimately, you can map (block 18) these adjusted measurements from the received seismic signals so that you can build a more accurate seismic image.

[055] for Example, to correct for the decline in marine seismic exploration counts on various compasses, obtained with the towed spit to define the locations of the sensors can be corrected in time and the current measurement�of declination in a defined area of interest. As discussed below, this may include the calibration of the declinometer, deployed on a towing vessel, to exclude effects of magnetically hard and magnetically soft iron, to set the current declination can be calculated and used to correct the readings on the compass throughout the towed streamers. Calculate declinations from the local base station can also be used for interpolation of the current declines in the area of intelligence.

[056] for Example, to correct for the decline in land seismic exploration of different readings obtained to determine the locations of the geophones, it is possible to adjust in time and relative dimensions in the current declination in a defined area of interest. As discussed below, this may include the use of measurements of the declinometer for local sensors and interpolated for declination with the local base stations in the vicinity of an exploration.

V. MARINE SEISMIC SYSTEM

[057] With regard to the understanding of the whole process of correction for inducing seismic exploration we now turn to the consideration of the details of the marine seismic system and corrections for declination that you can perform by using it.

[058] Fig. 2A-2C illustrates a marine seismic survey system 20 having a towing vessel 30 is coupled to a number of�about towed braid 60 with sensors 70. The system 20 may be similar to conventional marine seismic system used in a typical water spaces. However, as particularly shown, the system 20 can be used in ice-covered areas with glacial ice, pack ice, ice field, or other obstructions or barriers on the water surface, which can interact with towed components of the marine seismic system. In this particular system icebreaking vessel 20 35 reveals ice cover before the towing vessel 30. In marine seismic systems of various kinds, which in the process of intelligence information on the provisions of the towed CBS is going with the use of measurements of the geomagnetic field, such as the readings on the compass and magnetometer, either way, you can benefit from the correction for declination, as described in this application.

[059] When the towing vessel 30 tows the towed spit 60, with system 45 power supply is driven by the source 90, and seismic recorder in the control system 40 are recorded seismic data received by the sensors 70 on towed streamers 60. Continuing below the waterline of the vessel, the ice skeg 50 holds the point of attachment of the tow ropes 62/92 below the water surface. Cables towed 65 KOs, coupled with seismic registrato�Ohm control system 40, stretched from the vessel 30, and the skeg 50 directs these cables towed 65 KOs under the surface of the water, so that ice does not interact with them and not going around them.

[060] the Seismic source 90 has many elements 91 seismic source, which are typically air guns. The power cable 95 connected to the system 45 power stretched from the vessel 30. The tow rope 92 connects the cable 95 to the ice skeg 50 and facilitates the towing of the source 90 behind the vessel 30.

[061] As further shown in Fig. 2B, Paravani, stabilizers or gate 64 and the spacer 66 can be used to support numerous towed braid 60 behind the towing vessel 30. These Paravani 64 and spacer 66 may also be similar to conventional components used in marine seismic exploration, except that preferably, Paravani 64 was towed below the water surface.

[062] In marine seismic exploration, it is desirable to determine and track the position and be able to control the position of the towed braid 60 to improve the recording and mapping of the received seismic data. The determination of the absolute position can be done using counts (GPS readings) on the signals of global positioning system (GPS) obtained at buckeroomama 60 in the process of exploration.

[063] However, in a marine seismic survey system 20 according to the present disclosure obtaining GPS readings can be difficult, because the system 20 is submerged well below the surface of the water, so that the receivers of the GPS system (GPS receivers) can't work on getting samples. For this reason, in the system 20 includes a deployable device 80 on towed streamers 60 to help determine the absolute position of the towed braid 60, as well as for active position control them. In addition, samples of measurements of the geomagnetic field obtained by various sensors, such as the readings on the compass along the towed braid 60, there may be fluctuations in declination over time and over the exploration area. For this reason, in the system 20 using a method of correction for declination, as described below.

[064] we Now turn to the consideration of deployed or managed devices 80 several types that you can use on towed streamers 60 to obtain GPS readings or position control of the towed braid 60 in the process of exploration.

1. FLOATING DEPLOYABLE DEVICE

[065] Fig. 2C shows a marine seismic survey system 20 having a deployed device 80A of the first type according to the present disclosure. In the process of marine seismic provisions towed braid 60 R�guiraut and control, so the absolute position sensors 70 may be known for proper registration and analysis of data. For example, the coordinates of the tail of the towed spit, defined by the signals of the GPS system, can be used to coordinate the position of each of the sensors 70 on various towed streamers 60, and in the control system 40 these coordinated provisions may be used in recording, analysing and monitoring data. A suitable system for recording, analysis and control is an intelligent recording system from ION Geophysical, which can determine the position of the towed braid 60. In such a system, towed spits 60 can be controlled using control systems towed spits DIGIFIN™ and software for command control ORCA®, which is available from ION Geophysical. (DIGIFIN is a registered trademark of ION Geophysical, Corporation and ORCA is a registered trademark of Concept Systems Holdings Limited).

[066] In the presented exploratory system 20 of the towed spit 60 are moved submerged below the water surface through the use of the skeg 50 and other elements disclosed in this application. Nevertheless, it is still necessary to determine the position of the towed braid 60. To obtain the position taken separately towed spit 60 in the system 20 of figure 2C use� deployed device 80A, which floats at the water surface in the tail of the towed spit 60.

[067] the Deployed device 80A may be columnar buoy type, designed to withstand the impact of ice and debris fields of ice on the surface. Device 80A includes a receiver 82 GPS (GPS receiver) that can obtain the coordinates from the GPS system for the deployed device 80A, when it is towed behind the vessel 30 together with oblique towed 60. To get coordinates from the GPS system can be used conventional methods known in the art, so they are not described in detail in this application. For example, details relating to the determination on the basis of the GPS position of an underwater towed spit 60, can be found in U.S. patent No. 7190634, which is included in this application by reference.

[068] the towing vessel 30 of the towed spit 60 source 90 generates the signal source and the sensors 70 are detected seismic signals. The control device 40 receives the coordinates from the GPS system with a deployed device 80A when using the towed spit 60 and other lines for communication and power to the GPS receiver 82. Then using methods known in the art, in the control system 40 determines the position of the towed spit 60, sensors 70, source and other�their components relative to the vessel 30 and the physical coordinates to scout the area.

[069] Although in a marine seismic survey system 20 is used floating-deployed device 80A of figure 2C, its use is generally possible provided that the surface device 80A is designed to clash with a certain amount of rubble ice fields, fence or the like. Otherwise, the surface device 80A may wipe the ice, be damaged by impact, to move from his seat or lost. Therefore, in some situations, you may be able to use located deployable device 80, as described below.

2. MANAGED a DEPLOYABLE DEVICE

[070] it was Assumed that previous deployed device 80A floating on the surface. You can also use other devices disclosed in the application No. 12/719783 a US patent that is included in this application, and they may have buoys, floating anchor, cable, ropes, etc. note that the marine seismic survey system 20 in figure 2D has deployed device 80D, the immersion depth can be adjusted. In the process of exploration managed the deployed device 80D is towed in the rear of the towed spit 60 below the water surface to avoid collisions with debris fields of ice. To obtain GPS readings, the deployed device 80D has a GPS receiver 82d which can be driven on the surface�rnost by regulating the depth of immersion of the device 80D. Therefore, the deployed device 80D is preferably towed below the surface in line with oblique towed 60 and cause the surface to obtain a GPS receiver counts 82d at the appropriate time.

[071] Fig. 3A-3C shows the previously described, the deployed device 80D in two operating conditions. In the standard state planing of Fig. 3A, the deployed device 80D should be under the water behind the towed spit 60. This position is suitable when the surface waters are debris fields of ice, obstacles, or anything that can damage the deployed device 80D or to disturb him. When the surface is cleared of ice, the deployed device 80D can be lifted to the surface, whereby the GPS receiver 82d can get GPS readings. For adequate mapping of the group towed braid 60 and sensor 70 these GPS readings should be done at periodic intervals so that you can sufficiently track the position of the towed braid 60 and sensor 70.

[072] the Deployed device 80D can be guided vehicle, a device or a hydroplane. For example, in one arrangement, the deployed device 80D can be remotely operated vehicle (ROV) having a propulsion system and managed stabilizers or the like to control�management of the deployed device 80D to achieve the preset position in the water while towing. Alternatively, the deployed device 80D can be towed glider, which moves up or down when using the system buoyancy control, as described in more detail below. As another option, the deployed device 80D can be remotely operated towed vehicle (OAK), devoid of the propulsion system, but have managed stabilizers, as described in more detail below.

[073] According to these principles Fig. 4-5 illustrates embodiments of a deployable device or devices 150A-IN for an open marine seismic system 20. As shown in Fig. 4 and previously noted, the apparatus 150A is attached to the end of the seismic towed spit 60, which provides power supply and connection of apparatus 150A. This may be the cable, the cable 61. Stabilizers 154/156 on the unit 150A can be movable, and the device 150A may have a propulsion system 160, such as a screw. Alternatively stabilizers 154/156 not be movable. Instead, in the apparatus 150A system may be used buoyancy control, as described below. Similarly, the power unit can not be used in the apparatus 150A, and the system 160 on the unit 150A may actually be a brake, which is also described below.

[074] As shown, the apparatus 150A ima�t detector 165, designed for surface detection of obstacles. The detector 165 may include sonar, Profiler ice, light sensor, multi-beam echo sounder, camera, or something similar to review the upper hemisphere and monitoring obstacles (or leads) on the unit 150A. The signals from detector 165 may be integrated in the navigation and/or control system (not shown), such as the Orca system® designed for reception of marine seismic data. Thus, the management system can determine the moments at which the surface above the apparatus 150A ice-free and can generate a signal for lifting apparatus 150A on the surface of the water.

[075] for Example, the detector 165 you can use the sonar to detect when ice is present on the surface. For example, if the ice of a certain thickness is present on the surface, the sonar detector 165 may detect this ice surface, and this information can then be used to determine whether to raise the unit 150A or not. Preferably, the sonar detector 165 can detect thin ice, that is at least a thickness of less than 1 m, although it depends on its characteristics, the device 150A can be protected from most of the surface ice, which can �to risedronate.

[076] According to another example, the detector 165 may be an optical sensor that detects light from the surface, which may indicate the presence or absence of ice. According to these principles the detector 165 may be a digital camera on the towing vessel serves video or images along the towed spit 60. Tail towed braid 60 may be located at a considerable distance from the towing ship and the operators are not able to identify where the towed spit 60 and some ice can be above the apparatus 150A. Consequently, operators may consider the video, or images from the camera 165 and, if you have the lead, to determine whether to raise or not a particular device 150A. In addition, it can be done remotely by actuating devices 150A through signals transmitted from the vessel to the apparatus 150A according to the towed braids 60.

[077] the Apparatus 150A also has a GPS receiver 152. As shown, the GPS receiver 152 may be located on an upward stabilizer 154, so that the antenna 152 may protrude above the water surface when the apparatus 150A glicerol to the surface to obtain GPS readings. Regardless of the extent to which the GPS receiver 152 is raised above the surface, the GPS readings are taken and transmitted to the system control�managed devices for positioning a towed spit 60 and definition of its position, data were recorded and analysed appropriately.

[078] Since, as noted in this application, continuous GPS readings may not available, the unit 150A may include an inertial navigation system to maintain its direction periodically as determined by GPS readings. In addition, the unit 150A may include declinometer 167, which may be associated cable-a cable end portion of the apparatus 150A to keep it away from any interfering electronics. In the declinometer 167 you can use a three-component magnetometer to determine the declination in the earth's magnetic field, and then the declination can be adjusted relatively to the reference to true North, in the control system devices, it was possible to determine the absolute position of the tail section of the towed spit 60 in the absence of more affluent GPS readings that are typically used for this purpose. Instead of towing declinometer 167 at the end of the towed spit 60 declinometer 167 can be towed directly behind the vessel 30, preferably, usually at a distance of 2.5 of the vessel's length to reduce crosstalk from the magnetic field of the vessel. As will be described later, even more preferably to arrange the declinometer on the vessel 30.

[079] the Apparatus 150A periodically receives GPS readings at the output surface�knosti to receive GPS data through the GPS receiver 152. In this case, when immersed in water previously obtained data the GPS system can be used in the apparatus 150A along with the data of inertial navigation, the readings of the compass and the current data of the inclinometer to determine in real time or near real time position of the towed spit 60 on an ongoing basis until the newly developed GPS-readings.

[080] Fig. 5 shows some of the internal parts and components of the deployed device or apparatus 150V. Apparatus 150V stabilizers 154 is fixed in the apparatus and 150V not used powerplant. Instead, it uses the system buoyancy control, having a volume (for example, the camera 180) in the form of freely filled with water the rear part of the apparatus of 150V. Volume of this chamber 180 can be adjusted if the pumping system 182 or similar so that the buoyancy of the apparatus 150V could be varied in a controlled manner.

[081] To change the angle of pitch and roll of the device 150V mass 170 can be moved in the axial direction along the length of the apparatus 150V or rotate around the axis. Preferably, the weight 170 was a real battery used for the electronic components of the device, which include servo motors and other motor to move the mass of 170.

[082] In contrast to the GPS receptor�ku of Fig. 4, the GPS receiver 152, shown in Fig. 5, is located on the end of a long rod or mast 153. This rod 153 may continue upward at an angle relative to the apparatus 150V, so that the GPS receiver 152 may protrude from the water when the machine is 150V glicerol near the surface. As a variant of the mast 153 may be made rotatable in the base 155 of the provisions on stream in line with the device 150V to the position with a deviation up. When the machine 150V periodically appears on the surface to obtain GPS data, mast 153 on this basis, 155 can rotate the GPS receiver 152 of the water.

[083] In General, the apparatus 150V may have elements similar to the elements used in the apparatus and the drifting profilers, which in oceanic conditions measured deep-water currents, temperature, etc. As such, the apparatus 150V has a chassis (not shown), restraint system 180 variable buoyancy, weight 170 and section 190 of electronics. Isopenicillin frame 157 corresponding to the density of sea water, can be installed in sections on the chassis. Then frame 157 and chassis can be installed in a fiberglass housing 151 having stabilizers 154 and a streamlined shape. The mast 153 GPS receiver 152 can be joined with section 190 of electronics and you can continue from the main body 151.

[084] As was revealed when officially registered application�, these and other managed deployable device 80 can be used in the rear of the towed spit 60 (and other places). When the device 80 in the tail-end are presented to the surface to obtain GPS readings for determining the positions of towed streamers.

3. SYSTEM WITH MANAGED DEPLOYABLE DEVICES

[085] As noted earlier, managed a deployable device 80 can be used in the rear of the towed braid 60 for regulating provisions towed braid 60. As also previously noted, the device 80 may include remotely operated towed vehicles (OAK), in which there is no propulsion system, but have managed stabilizers. Figure 6A shows a side view of the marine seismic survey system 20 having a remotely operated towed vehicle (OAK) 200 as a managed device in the tail of the towed spit 60. Remotely operated towed apparatus 200 is towed on the end of the towed spit 60 below the surface of the water. This remotely operated towed apparatus 200 also has a GPS receiver 212, which may obtain GPS readings after bringing remote controlled towed apparatus 200 to the surface.

[086] Fig. 6B shows a plan view of marine seismic sistemy, having a remotely operated towed apparatus 200 at many places towed braid 60. In this system, the head of the remotely operated towed apparatus 200A towed towed before scythes 60, and the tail of the remotely operated towed apparatus 200V towed at the ends of the towing CBS 60. Head remotely operated towed apparatus 200A is attached via the tow ropes cables 62 and 65 towed KOs coming out of the skeg vessel 50. Optional additional intermediate remotely operated towed apparatus (not shown) can be deployed in intermediate locations along the towed braid 60.

[087] To perform work in three dimensions (even in two dimensions or four dimensions) each head of remotely operated towed apparatus 200A individually tows the towed spit 60. Towing ropes and cables 62/65 towing KOs connect remotely operated towed apparatus 200A with skeg vessel 50. In the process of exploration the position and depth of each remotely operated towed apparatus 200A-b can be adjusted to maintain proper location of the group towed braid 60 during seismic surveys. In addition, the regulation of the depth of immersion allows you to delete stalks�the venue towed braid 60 with any medium floes on the surface.

[088] When using remotely operated towed apparatus 200A-IN on head and tail locations along towed braid 60 could facilitate the production and selection towed braid 60. For example, being independent from each other, individual remotely operated towed apparatus 200A-b may send the towed spit 60 down under other towed spit 60 and can bring her up to the surface through the middle of the group towed braid 60 on potentially free from ice the area behind the vessel 30. After that towed spit 60 can be chosen at the ship 30 and thus it is possible to avoid contact with other towed spits and 60 tow rope 62. This allows operators to issue and choose the towed spit 60 individually and even allows you to repair the towed spit 60 at a time when other towed spit 60 remain in the water. When using a single remotely operated towed apparatus 200 in the tail of the towed spit 60, as in the system of Fig. 6A, the issue and the choice can be made similarly.

[089] Fig. 7A-7B shows in greater detail a remotely operated towed vehicle (OAK) 200 according to one embodiment of the. In General, this is a remote operated towed apparatus 200 is a device of the hybrid type including � elements of remotely operated vehicles, Autonomous underwater vehicles and gliders. One suitable example of a remotely operated towed apparatus 200 is towed undulator TRIAXUS, which can be obtained from the MacArtney Underwater Technology Group.

[090] For towing remotely operated towed apparatus 200 towing cable (not shown) having power wires and communication lines, connected to the front edge 49 of the Central underwater wing 227. As shown, a remote operated towed apparatus 200 has four tubular member 210 connected in front of hydrofoils 220/225 and rear flaps 230. Underwater wings 220/225 and flaps 230 have a wing profile. Central underwater wings 225 connect leading underwater wings 220 and horizontal support wing scuba 227 in the front of the remotely operated towed apparatus 200. These Central underwater wings 225 contribute to the retention of remotely operated towed apparatus 200 is aligned on a roll. Tail flaps 230 is made manageable, the upper and lower flaps 230A-TO regulate the pitch angle, and the right and left flaps 230C-D regulate the yaw rate.

[091] the Four actuator or motor (not shown) installed in each of the tubular members 210, move these flaps 230A-D to control the pitch angle and R�Scania remotely operated towed apparatus 200, when it is towed. Tubular elements 210 have compartments 212 for placing the various components in addition to engines, gearboxes and encoders flaps 230A-D. for Example, in these compartments 212 may be a GPS receiver, inertial navigation system, a depth sensor, the sensor pitch, roll sensor, a heading sensor, etc., which are described below.

[092] When towing a horizontal flaps 230A-TO create upward and downward force to move the remotely operated towed apparatus 200 vertically, whereas the vertical flaps 230C-D create directed right and left forces to move the remotely operated towed apparatus 200 horizontally (transversely). Usually remotely operated towed apparatus 200 is towed in a neutral position, wherein the flap 230 is periodically adjusted to maintain remotely operated towed apparatus 200 in a position in which it is located. In some situations, such as lifting, require a more active movement of the flaps, especially when connected with oblique towed. For braking remotely operated towed apparatus 200 can use some of the methods described earlier. In addition or alternatively, the flaps 230 can�archiving inward or outward to increase the drag of remotely operated towed apparatus, when it is towed.

[093] In Fig. 8 schematically shows the elements of the management system 300 designed control managed devices (e.g., remotely operated towed apparatus 200) and determining their provisions when towing a marine seismic system according to the present disclosure. Ship components 305 on the vessel 30 includes main control system 310, which has a primary GPS receiver 320 for receiving the GPS readings. As before, this control system 310 may be a control system devices, such as Orca®, which is available from ION Geophysical. Control system 310 is interfaced (or combined) with a control unit 330, which controls various devices (e.g., remotely operated towed apparatus) used in towed streamers in the group, and monitors them. An example of a suitable control unit 330 for remotely operated towed apparatus 200 of Fig. 7A-7B is a surface unit that is used for remotely operated towed apparatus TRIAXUS.

[094] Connected by lines 332 communication and the power control unit 330 is coupled to the local controller 350 of the managed device 340, such as, for example, remotely operated towed apparatus 200 of Fig. 7A-7B or some other controlled device, RA�covered in this application. The controller 350 transmits the sensor data from the sensors 360 device to the control unit 330. After agreeing to navigation instructions from the navigation information in the main control system 310, the control unit 330 sends them back to the controller 350, which accordingly actuates the motors 370 different stabilizers. Implementing managed navigation apparatus 340 may include a real-time control and pre-programmed trajectory.

[095] the Controller 350 is connected with built-in sensors 360 devices and engines with 370 flaps. Built-in sensors 360 to control the device 340 includes a depth sensor, the sensor pitch, roll sensor and a heading sensor. The immersion depth can be measured by the pressure sensor, whereas the pitch angle and the roll can be measured by two-component inclinometers. The or yaw rate can be measured when using an induction compass, and you can also use the altimeter.

[096] In addition to the built-in sensors 360 controller 350 may be connected to position sensors which control motors and flaps, tracking the position of these flaps with data transmission on the feedback channel to the control unit 330. All these built-in sensors (i.e., pitch, roll, heading, and position of the motor shaft) to provide�Ecevit feedback to the control system 310, to control the flaps for the direction of the managed apparatus 340 and retaining it from yawing.

[097] In addition to these sensors, the controller 350 on the managed device 340 is connected to a GPS receiver 380. As noted earlier, when the managed apparatus 340 is provided to a surface, the antenna of the GPS receiver 380 may extend to the water surface to obtain GPS readings. Should still expect that such counts will be made periodically. In all likelihood, when used in ice-covered or clogged waters of the managed device 340 can be continuously towed under the rubble ice fields for hours or even days before you can re-raise to the surface to obtain GPS readings. For this reason, the managed apparatus 340 also has the device 390 inertial navigation systems (ins) used to determine the relative position or location of the managed device 340 in the intervals between the direct GPS readings received from a GPS receiver 380.

[098] In General, the device 390 inertial navigation systems you can use components known in the art, such as the processor, accelerometers and gyroscopes, and use methods of reckoning the way for the continuous determination of position, orientation, direction and speed at�rassimov apparatus 340. Thus, depending on the duration of the read path of the managed apparatus 340 drift error inherent in the measurement of acceleration and angular rate device 390 inertial navigation systems, more and more increasing. In accordance with this navigation should preferably be corrected with periodic GPS readings. Even under uncertainty, which is a part of nautical miles (mile=1853,25 m) per hour for the position and a few tenths of a degree per hour in orientation, the error determining unit 390 inertial navigation systems can be significant if the managed device 340 remains below the surface for an extended period of time. The following review describes a feedback loop that can be used for the correction calculation performed by the device 390 inertial navigation system.

4. The CONTROL CIRCUIT

[099] Fig. 9 shows an example of the navigation circuit 400 feedback, intended to determine the position of the controlled apparatus (for example, 340; Fig. 8), such as remotely operated towed apparatus, and correction of this situation. In accordance with the contour of the first 400 in a managed device 340 receives (block 402) direct the GPS readout when using a GPS receiver 380. Doing this at a time when� plot above managed apparatus 340 is free from debris fields of ice, and other obstacles. After the managed device 340 is again immersed, the device 390 inertial navigation system and control system 310 begin to determine (block 404) the position of the controlled device 340 when towing. This is done by using the methods of notation of the source location or binding on the basis of the GPS reference and measure the direction, speed and time to calculate the position of the controlled device 340, reaching forward from the original location.

[100] unfortunately, inertial navigation of this species is not accurate, and the drift error accumulates over time. Under the condition that the drift error is low enough that inertial navigation can continue. At some point of time, the management system 310 determines (block 406), does not exceed the drift error of a certain margin, which depends on the implementation. If not exceed, the management system 310 may continue the reckoning (block 404) the way up until the drift surface will not be very large.

[101] After the drift error becomes large (due to a sustained period number of ways, a high speed of intelligence, to a large extent the intelligence or their combination), the management system 310 makes an attempt to correct the error when re sply�AI on the surface of the controlled device 340 by obtaining a new GPS reference which is determined by the position of the device 340, or by integrating the number of paths the device inertial navigation system using feedback from the navigation system of the vessel. Accordingly, the management system 310 determines based on the data entered manually, or data from sensors (sonar, ice profilometer, depth gauge, etc.) on the managed device 340 if (decision 408) device 340 to rise to the surface to get (block 402) different GPS reference for determining the device's location to repeat the process.

[102] If the managed device 340 may not float to the surface, the control system 310 receives (block 410) GPS reference when using the onboard GPS receiver 380 on the ship. This GPS reference given the location of the towing vessel 30. In addition, the system 310 receives (block 412) the data from the different being afloat devices (for example, a managed device 340 coupled to the spit, sensors, etc.). You can use this data to determine the relative position of the controlled device 340.

[103] for Example, in Fig. 10 illustrates a marine seismic system 20 having towed spit 60 cable compasses or sensors 70 located therein, to determine the shape of the towed spit. In this case, to define�ing use GPS-count (x) from ship components 305, known location (Y1-Y5) sensors, known location (Y6) of the managed machine along the towed spit 60 and various compass courses from cable compasses 70 or the like. As shown, data from sensors 70 and the managed device 340 on the towed spit 60 (including each of its provisions (Y) on the towed spit, compass courses, adjusted in accordance with the declination, etc.) can be used to assess the position of points on the towed spit 60 and receiving the forms of the towed spit. In combination with the vessel's GPS-count (X) when using on-Board GPS receiver of the number of ship components 305 all these data can be combined with location data from the device inertial navigation system (390; Fig. 8) for correcting the drift error and the information about the absolute position relative to the location of the towed spit 60 and sensor 70 in the coordinates of the GPS system or similar.

[104] in addition, acoustic methods of location determination may be combined with the GPS readout when using on-Board GPS receiver of the number of ship components 305 to correct the drift error of the instrument inertial navigation systems and more information about absolute position. For example, in Fig. 11 shows various configurations of the acoustic foam�related systems for the implementation of acoustic crosstalk in the system 20. This acoustic crosstalk can be used for determining the positions of towed streamers.

[105] in addition, a short baseline can be obtained when using a transducer on the vessel 30 for irradiation of acoustic acoustic pulse sensor on the managed device 340 in the direction towards the rear end of the towed spit 60 to determine the position of the vehicle. In addition, long base line can be obtained by using one or more other converters on the seabed (at least two Converter required for a system with a long base line) for irradiation of acoustic pulse sensor on the managed device 340 to determine its position. Finally, even the control samples from the sensors of the controlled apparatus 340 and displacement, with respect to which instructions are sent to the managed device 340 marine components 305 (that is, the control unit 330), can be combined with onboard GPS reading (X) to determine the absolute position of the controlled apparatus 340. You can use these or other methods available in the art.

[106] Regardless of how the position of the device inertial navigation system is combined with feedback from other navigation components, ship components 305 is adjusted objectified�by the dead reckoning path (relative) position of the controlled apparatus (see block 414 in Fig. 9), so the system can continue using the appliance 390 inertial navigation systems with less drift error. The whole process of dead reckoning path and correcting the drift error may continue so long as the managed apparatus 340 remains submerged below the surface. Over time, if conditions permit, the managed device 340 will be sent to the surface for receiving (block 402 in Fig. 9) direct the GPS reference again to bind the location of the device. This new GPS-count will provide a new starting point, which can then be used in the dead reckoning path and correction until the managed device 340 remains immersed with further exploration.

C. CORRECTION FOR the DECLINE IN MARINE SEISMIC EXPLORATION

[107] As noted earlier, information about the position of the towed braid 60 during seismic surveys can be obtained when using one or more compasses, acoustic measurements or the like for determining positions of towed braid 60 and the provisions in relation to each other. Although treatment is done to the cable compasses, the ideas of the present disclosure can be used for the correction of any device for measuring the geomagnetic field, for example, for correction of magnetic exchange device relative to true �Eber. Measurement of provisions you can perform when using the tools or sensors installed on the towed streamers 60, and a measurement at standard sea exploration with a closed course or in the exploration in water with ice and with an open course. Eventually, when the Maritime exploration of any kind can benefit from the techniques disclosed in this application.

[108] As noted previously, the instant measurement of the declination useful for correcting determined magnetically locations towed braid 60 which receive cable compasses or the like. This correction is especially useful in higher latitudes, because of the large magnetic variation may occur at high latitudes due to atmospheric discharges. Finally, as discussed earlier, the ice in the water prevents the use of tail buoys and restricts the reception of the GPS readings at the end of the towed braid 60 so that the correction for declination can improve accuracy.

[109] As noted above, one way of obtaining the necessary GPS samples in the tail of the towed spit 60 includes the use of floating or tethered buoys (e.g., 82 in Fig. 2A) or involves moving a managed device to the surface to obtain GPS readings when possible (Fig. 2D, 3A-3B, 4, 5 and AV). In this case, the dead reckoning path or inertial navigation can be used to monitor the provisions of the towed braid 60 between periodic GPS readings, as it was described when referring to Fig. 7A-7B, 8 and 9. Of these calculations can be based on the testimony of the declinometer in the managed device in the tail of the towed spit 60, as was previously described when referring to Fig. 2B and 4.

[110] When using the declinometer is possible to correct the readings on cable compasses used to determine the location of the towed braid 60. When towing a declinometer behind the vessel 30, for example in the tail of the towed spit or in a managed device on the towed spit 60, declinometer is at a distance from the vessel 30. In this position of the declinometer can exclude the problems associated with the magnetic field of the vessel. Instead of towing the declinometer at the end of the towed spit 60, declinometer can be towed directly behind the vessel 30, usually at a distance greater than 2.5 times the length of the vessel, to reduce the influence of the magnetic field of the vessel.

[111] In the declinometer is preferable to use a vector magnetometer to measure the directional components of the magnetic field of the earth relative to the spatial orientation of the magnetometers. When towing a declinometer on boxi�creating 60 or spit behind the vessel 30, the magnetometer is moved, so that may require continuous correction of the spatial orientation of the magnetometer using inertial measurements, etc. This is especially true when the magnetometer in the declinometer is a strapdown three-component magnetometer, unlike scalar magnetometer, which measures only the total field.

[112] However, in most situations any induced from vessel 30 magnetism in comparison with the rapid movement of such towed magnetometer may not have negative side effects, so towing declinometer behind the vessel 30 is less than desirable. For these reasons, the towing vessel 30 may have a system for measuring the declination installed on it. However, when the system of measurement of the declination on the vessel 30 is necessary to compensate for the effects of magnetically hard and magnetically soft iron, created by the vessel 30. In the examination which follows, outlines the details of the calibration and use of the system for measuring the declination on the vessel 30 in marine seismic exploration. And in this case, the exploration may be conducted or may be conducted in waters with ice or obstacles, which receive continuous GPS readings on towed streamers 60 is difficult or impossible.

[113] Fig. 12A-12B schematically shows� control system 500 for the vessel 30, the towing of the towed spit 60. Although in Fig. 12A shows the ship 30 coupled to the skeg 50 one towed spit 60, but, as shown in Fig. 12B, it is possible to use more towed braid 60. Each of the towed spit 60 has a certain amount of magnetic exchange devices or cable compasses 65 located along its length, designed to identify and adjusting the position of the towed spit during towing. When using the system 520 measurement of the declination control system 500 receives the readings of the declination on the vessel 30, and adjusts the spatial and time readouts cable compasses 65 on the basis of readings of the declination. In addition, in the control system 500 can use the components of the control system devices, such as Orca®, which is available from ION Geophysical, and you can use similar components previously described, for adjusting the provisions of the towed braid 60.

[114] the Control system 500 has a control unit 510, which regulates and monitors various towed spit 60 in the group, as well as other sensors. It should be clear, although it is not shown in detail, the control unit 510 can be used components known in the art, such as processors, storage devices, storage device, the program�mnoe software, user interfaces, etc.

[115] for Example, to regulate towed braid 60, the control unit 510 is coupled with towed vehicles, managed devices, stabilizers, blades and other components (not shown) designed to control the towed braid 60 and the direction, as disclosed in this application and used in the art. To monitor the situation and determine the declination control unit 510 is coupled with cable compasses 65 on towed streamers 60 and paired with magnetometer 550, block 560 inertial measurements and course device 570 that operates according to the signals of the GPS system (course a GPS device), system 520 measurement of the declination on the vessel 30. Course GPS unit 570 receives the GPS readings on the towing vessel 30 and the magnetometer 550 receives three directional magnetic components and can be fluxgate magnetometer, strapdown magnetometer or similar. It is preferable that exchange GPS device 570 had two GPS receiver (not shown) for receiving the GPS readings and the computation of geodesics, the bearing in accordance with methods known and used in the art.

[116] Block 560 inertial measurement gets three directional components of the motion of the vessel. For example, block 560 may have a sensor pitch, d�tcic roll and heading sensor. The pitch angle and the roll can be measured by two-component inclinometers. The yaw rate can be measured when using an induction compass, but other devices can also be used.

[117] To facilitate the review used different orientations refer to Fig. 12C-12D, which shows the geomagnetic coordinate system and the coordinate system of the vessel. Fig. 12C schematically shows the elements of the geomagnetic field for a point in space. Elements include North component Xe, East component Yeand vertical component Ze. Based on these components it is possible to obtain the horizontal component H of tension full of tension F, the angle I is the inclination and the declination angle D (measured clockwise from true North to the horizontal component).

[118] Fig. 12D schematically shows the coordinate system of the vessel with angles of spatial position, measured relative to true North and the horizontal plane. As usual, the inertial coordinate system of the vessel has an x-component Xs(measured positively in the direction from the bow of the vessel), the y component of Ys(measured positively in the direction from the right side) and z-component of Zs(measured positively down the keel). When the ship moves, it mo�em to have other angles of spatial position in its own coordinate system to geographic coordinates. The rate is measured around the vertical axis (Zs), while the roll is measured around the longitudinal axis (Xs). The pitch angle is measured around the transverse axis (Ys).

[119] Tied to the movement of the ship magnetometer 550, which may be a ternary strapdown magnetometer measures the geomagnetic field according to the spatial orientation of the vessel. Consequently, measurements of the magnetometer should be done not rotated for proper binding to the absolute coordinate system (i.e., to the true North, latitude, longitude, etc.) by using methods known in the art.

[120] Fig. 13 shows a General block diagram of the sequence of actions during seismic surveys 600 using declination, defined on the vessel 30 from the control system 500 of Fig. 12A-12B. To conduct seismic exploration, operators primarily calibrated (block 602) an onboard system 520 measurement of the declination on the vessel 30. As described below, during the calibration process in the control system 500 has the ability to take into account magnetic effects of the vessel 30 in obtaining magnetometer readings, etc.

[121] After calibration operators begin (block 604) seismic exploration. As noted earlier, intelligence includes towing towing vessel 30 of one or more of Buxi�creating CBS 60 in the group behind the vessel 30 for representing the region of interest. The source signals are reflected by the characteristics of the reservoir, and acoustic sensors on towed streamers 60 receive seismic signals for analysis. To combine all the data and ultimately construct the image of a region of interest of the seismic signals should be correlated with information about the location of the sensors on the towed spit 60, and a time of reception of signals in the process of exploration. You can use many of the known methods is designed to provide marine seismic exploration.

[122] As is usually done during marine seismic exploration, the control unit 510 receives (block 606) reports compasses with cable compasses towed 65 KOs and receives (block 608) the GPS readings from one or more GPS receivers. For example, different cable compasses 65 on towed streamers 60 get readings on the compass at the points along the towed braid 60 and the GPS receiver 570 on the towing vessel 30 receives the GPS position of the vessel counts. Subject to availability GPS receivers (not shown) on the tail buoys or other managed devices coupled to the towed streamers 60, can also get the GPS readings, although, as discussed previously, this may occur periodically.

[123] Then counts with cable compasses 65 correct (block 610) for the impact of the current decline, and et� readings may be taken into account when using methods of calibration and calculations, described in more detail below. Briefly, the original readings on the compass from compasses towed 65 KOs usually store without correction for the influence of the current declination, defined on the vessel 30. To perform this correction, the control unit 510 determines the difference of the first geodetic rate obtained when using the data system with GPS course GPS unit 570, the second geodetic rate obtained when using the data of three-component magnetometer 550. Based on this, the control unit 510 calculates the magnetic declination. In addition, the control unit 510 applies to magnetic declination compensation for the effect of motion of the block 560 three-component inertial measurements. Then the magnetic declination can be applied to the initial readings on the compass from compasses 65, and the resulting data can be saved as adjusted readings on the compass in the base 542 of the data system.

[124] When using the navigation software and renown layout towed braid 60, separation of sensors and readings on the compass, the results of determination of cross-connections, etc., the control unit 510 may be adjusted (block 612) the position of the towed braid 60, when it is desirable for intelligence. Then all of the relevant provisions of the towed KOs, the acoustic samples�ski sensors towed braid 60, the readings on the compass, GPS readings, inclination, etc. can be stored in the database 542 data for subsequent processing and analysis, which is usual for marine seismic exploration, so you can build an image area of interest.

[125] With this General review of seismic exploration in which the declination is determined by the system 520 measurement of the declination on the vessel 30, now, consideration will be given to the characteristics of the calibration system 520 measurement of the declination of the ship, to be able to identify and use the declination correction of the samples on the compasses on towed streamers 60.

1. The CALIBRATION METHODS

[126] To determine the exact magnetic declination control unit 510 on the towing vessel 30 must be completed in different stages of calibration. With a single calibration control block 510 calibrates the effects of magnetically hard and magnetically soft iron, while identifying three-dimensional effects of magnetically hard and magnetically soft iron steel towing vessel 30 according to the indications of the different data devices 550, 560 and 570 on the vessel 30.

[127] to do this, the control unit 510 calibrates the induced magnetization to compensate for the influence of the induced magnetic forces caused by the orientation of the ship in the earth's magnetic field. When this calibration is used to�ivaya deviations of Fourier series. In addition, control unit 510 performs the binding interpolated internal field received from remote base stations or observatories, for accurate estimation of magnetic declination at the place of calibration. In this case, control unit 510 uses data from base stations located at some distance from the place of calibration. Each of these calibration steps are described in detail below.

A. CALIBRATION PROCESSES

[128] the calibration of the effects of magnetically hard and magnetically soft iron of the towing vessel 30 control unit 510 based on the known characteristics of the earth's magnetic field and ferromagnetism steel vessel 30. As you know, the earth's geomagnetic field has a value, the inclination relative to the horizontal and declination with respect to true North. These field components can be decomposed into geometric components of Mx, Myand Mzthat can be obtained by the magnetometer 550 system. These components correspond to the typical coordinate system or the rule counts for magnetometers. This rule counts often known as the North-East-vertical and the X axis points to the North horizontally, the Y axis points East of horizontally and the Z axis points down vertically.

[129] the total magnetic field (B) land in a particular place presented�splash zones is the sum of three physical components: the main field (B m) in the earth's core, cortical fields (Inwith) near the surface of the earth's crust and most variable atmospheric field (Bd). These three fields (BmBcand Bdtake into account in the calibration of the declinometer.

[130] the magnetic field Vector (In) the earth has components defined in a geodetic coordinate system. As mentioned earlier when referring to figs. 12C, the geodetic coordinate system has an x-component Xe(measured positively to the North), the y component of Ye(measured positively to the East) and z-component of Ze(measured positively down to the center of the earth). Main field (Bm) represents the largest component of the total magnetic field (B), containing about 98%, and it can be predicted with the help of several models. Some typical models include the international geomagnetic reference field (MAGP), the world magnetic model (AMM), an enhanced magnetic model (UMM) and the global geomagnetic model (SGM) British geological survey (BGS). One or more of these models used in the calibration procedure described below.

[131] for its part, the cortical field (Inwithmay become known only when the local magnetic studies, which in most cases is not carried out. This can be overcome by calibration at the IU�e deep water, to minimizewith. Changeable atmospheric field (Bd) can be estimated by interpolated data provided by magnetic observatories, assigned to the studied region. Such observatories are strategically located around the world and their data can be used for the evaluation of atmospheric volatile field (Bd) interest in the region.

[132] Ferromagnetism are two types of interest in the calibration system 500. First iron design of the towing vessel 30, which is in the earth's magnetic field, so that the vessel 30 to register residual or permanent magnetism during the physical design process. This ferromagnetism is a so-called magnetism magnetic solid iron and is permanently associated with the vessel 30, even when its orientation is changed. Thus, when the magnetometer 550 receives the samples, the magnetism of magnetic solid iron that is associated with the vessel 30, is constantly added to the output signal for each axis of the magnetometer 550.

[133] of interest ferromagnetism of the second type is the induced magnetism created by the interaction of the magnetic field of the earth and iron vessel 30. This induced magnetism is a so-called magnetism magnetic soft iron, and he izmenaet� (fluctuates), when the vessel 30 changes the orientation in the earth's magnetic field. The calculation of the effects of magnetic soft iron is more time consuming than the computation of the effects of magnetic solid iron, and includes the definition of the angle (Phi), which is horizontal counts Mx/Mymagnetometer is rotated horizontally. The calculation also includes the determination of the ratio (R) of the major axis to minor axis in a horizontal rejected samples Mx/Mythe magnetometer. When used together, the angle (Phi) and relations (R) compensate for induced magnetism (magnetic soft iron) in the horizontal plane. Specific equations to identify the angle, the magnitude of the major axis, matrix, rotation, and scale factor of major axis is known in the art and for the sake of brevity will not again be formulated in detail in this application.

[134] the Ferromagnetism of both these types of acts in horizontal planes (Mx, My) and vertical plane (Mz). Therefore, to determine the adjustment parameters in the calibration process, it is preferable to compensate for magnetism magnetically hard and magnetically soft iron in horizontal and vertical planes.

B. BLOCK DIAGRAM of the SEQUENCE of ACTIONS

[135] In the block diagram of the sequence of actions from Fig. 14 shows p�the process 630 calibration which can be implemented as a software or something like that in the programmable processor control unit, disclosed in this application. In the process 630 calibration determine the azimuth of the measurement system 520 declination relative to magnetic North. To do this, the process 630 use the rotated offset components of the observed magnetic field, obtained with the help of samples (Mx, Myand Mz) magnetometer when the vessel 30 is set to the calibration route. Then the magnetic azimuth from that of the observed magnetic field is compared with the azimuth, the resulting exchange rate of the GPS device/the unit the inertial measurement 570/560, with respect to true North, which gives the declination for correction of various readings on the compass on towed streamers 60.

[136] First, the operators perform (block 632) gauge the passage of a vessel 30 for the calibration system 520 of measurement deviation. In this case the ship goes on a circular route, so that the ship's course runs over all azimuths, while the azimuth is the angle in the horizontal plane, measured clockwise from the bearing of the North. For the vessel 30 can be used two routes 620/625 shown in Fig. 15A-15B. When the vessel 30 is in route 620/625, control system 510 registers (block 634) calibration data, including the course according to Kursova� GPS/inertial unit of measurement, the pitch angle and the roll unit 560 inertial measurements; three counts Mx, Myand Mzwith the magnetometer 550; GPS readings of latitude and longitude from the GPS receiver 570; and time stamps for all preceding data. Then the calibration data is stored (block 636) for processing, described in detail below, to obtain the parameters for the correction of future samples.

[137] For the calibration of the control unit 510 rotates (block 638) magnetometer raw data horizontally using the received data of GPS/inertial unit of measurement. After this is done, various calculations are performed to find the calibration parameters that can be used to correct the readings on the compass and seismic data on the basis of changes of the declination, which is manifested in the process of seismic exploration. As part of this calculation, the control unit 510 determines the calibration parameters for the effect of magnetically hard and magnetically soft iron in a vertical orientation (block 640) and in the horizontal orientation (block 642).

[138] with regard to the computed calibration parameters, control unit 510 also performs calculations that can compensate for (block 644) atmospheric variations in the earth's magnetic field. As explained in more detail later, this can be done when �ispolzovanie location data from around the observatories. Finally, after completing the calibration, the control unit 510 may be used (block 646), the calibration parameters in the registration and data processing compasses towed KOs, with changes in the declination, when you run or analyze the results of the seismic survey.

C. the FIRST STAGE of CALIBRATION

[139] With regard to the understanding of the overall process 630 calibration described above, consideration now will be turned to Fig. 16A, where the first stage 650 of calibration are shown in more detail. (Stages stage 650 may be implemented as software or the like in the programmable processor control unit, disclosed in this application.) As previously noted, after the passage of the vessel 30 on the route (620/625 in Fig. 15A-15B) and receive counts for all azimuths, the control unit 510 first turns (block 652) the original data (Mx, My, Mz) magnetometer magnetometer with 550 horizontal when using the pitch angle and roll received at block 560 inertial measurements. To do this, the rotation will be applied to the magnetometer data for removal of the roll (i.e., roll angle between the axis X and the horizontal line) and the other turn is used to remove pitch (i.e., pitch angle between the X axis and horizontal). Thus the rotation of the local horizontal x-y plane is aligned to e�alonday the horizontal X-Y plane and can use a rotation matrix and calculations, known in the art.

[140] After that, control unit 510 determines (block 654) rotated vertical component of Mzas a function of the azimuth according to the GPS/inertial unit of measurement when using the deflection curve of the fourth order for the Fourier series and least squares method. The selection of this curve are vertical parameters of magnetically soft iron (9 coefficients) to compensate for the effects of magnetic soft iron in a vertical plane.

[141] Fig. 17 graphically illustrates the step of determining a rotated vertical component of Mzas a function of azimuth on the basis of the GPS readings/readings unit inertial measurement when using the deflection curve of the fourth order for the Fourier series and least squares method. In this case, the initial vertical component of Mzshown as line 680, and rotated vertical component of the Mzshown as line 682. Found curve is rotated to the vertical component of the Mzshown as line 684, in this case rotated vertical component of the Mz(nanotesla) depicted on the chart as a function of the azimuth according to the unit the inertial measurement unit 560 inertial measurements. As a result of performing these steps in the process 630 receive calibration parameters to compensate hover�steering magnetism (effects of magnetic soft iron) vertically due to the vessel 30. Vertical parameters of magnetically soft iron get through the nine coefficients of the Fourier series for line 684 best match.

[142] turning Now to Fig. 16A, where the control unit 510 carries out (blocks of 665 656) iteration within a few steps after finding the vertical parameters of magnetically soft iron, in order to determine the parameters to compensate for residual magnetism (effects of magnetic solid iron) vertically.

[143] Along with the iteration within the sequence, vertical correction coefficients Mz0adjand for each data point in the calibration of the circle, cross the vessel 30 during the process is (block 656) solution for Mz0=Fourier (function of azimuth) minus the correction factor Mz0adjand is a division of Mz0for cos(pitch angle)∗cos(roll). (When computing Mz0adjrepresents the value of residual magnetization vertical that minimizes the standard deviation (SO) of the horizontal ellipse (Mhin nanotesla. During this operation essentially turn the vertical component of Mz0azimuth relative to the orientation of the vessel. In addition, the absolute value of the turning of the vertical component of Mzazimuth is reduced due to overnutrition M z0. With decreasing Mzchange the rotated components of Mxand My. Therefore, the control unit 510 rotates (block 658) magnetometer data (the source component of Mxoriginal component of Mymodified downward component of Mz) horizontally when using the pitch angle and roll from block 560 inertial measurements.

[144] the Horizontal components of Mxand Mymagnetometer form a horizontal field components. When plotting Mxin the horizontal plane as a function of Myhorizontal component of the observed magnetic field is characterized by an ellipse. During calibration of the horizontal component should be circular if it is not distorted by the effects of magnetically soft and magnetically hard iron from the vessel 30. However, since the magnetometer data are skewed horizontal component of the observed magnetic field changes and moves, rotates, and an elliptical shape is observed when building in a horizontal plane graph Mxand My. When understanding how the ellipse Mhthe horizontal field is distorted relative to the ideal circular shape, various parameters describing the effects of magnetically soft and magnetically hard iron from the vessel 30 can be identified by �tsteam magnetometer in the horizontal plane.

[145] After the rotation (block 658) magnetometer data control block 510 using the least squares method simultaneously determines (block 660) the parameters of the ellipse Mhthe horizontal field. The implementation of this involves finding two displacements (X0and Y0) angle (Phi) orientation and relationship (R) the major and minor axes of the ellipse Mhin accordance with which distorts the ideal form in the case of obtaining magnetometer readings from the real magnetometer.

[146] Move X0represents the displacement in the X direction of the horizontal field, and moving the Y0represents the displacement in the Y direction of the horizontal field. These two displacements (X0and Y0) compensate for residual magnetism (magnetic solid iron) horizontally. Essentially, these displacements (X0and Y0) shows what shifts applied to the ellipse Mhhorizontal field after correction for the influence of pitch and roll to compensate for the shift in the horizontal plane effects of magnetic solid iron. The angle (Phi) is the angular orientation of the ellipse Mhhorizontal field horizontally, and the ratio (R) is the ratio of the major and minor axes of the ellipse Mhthe horizontal field. When used together, the angle (Phi) and relations (R) implement�makes compensation of the induced magnetism (magnetic soft iron) in the horizontal plane.

[147] Then, during the process by moving and rounding ellipse of Mhhorizontal field, i.e., find (block 642), under what parameters the ellipse Mhthe horizontal field is conformal perfect circular shape, if the magnetometer data are not distorted by the effects of magnetically soft and magnetically hard iron. In this case, in the calibration process are iteratively the parameters, which determine the distortion due to the influence of magnetically hard and magnetically soft iron, magnetometer data, by selecting a value of the correction factor Mz0adjthat minimizes the standard deviation (so) of the horizontal field (Mhfrom an ideal.

[148] In particular, during the process define move (X0and Y0), according to which the ellipse of Mhthe horizontal field is shifted to (0, 0) in the horizontal plane Mx/My. During the process also determine the angle (Phi), which is rotated ellipse Mhhorizontal field, so that during the process can be found the ratio (R) of the major and minor axes, are necessary in order to make a circular ellipse by increasing the minor axis. Then after you determine the relationship in the process, ellipse Mhthe horizontal field can be rotated back to a certain angle (the EU�ü, Phi) for recovery orientation.

[149] At this point the iterative process of Fig. 16A, the control unit 510 calculates (block 664) standard deviation for all data points based on the settings that were used in the current iteration of the solution. In particular, for all data points the controller 510 calculates the standard deviation (SO) of the ellipse Mhthe horizontal field as the square root of (Mx2+My2). Then, the control unit 510 selects (block 665) correction factor Mz0adjthat minimizes the standard deviation (SO) of the ellipse Mhthe horizontal field from the ideal circular shape. This value of the correction factor Mz0adjassociated with specific parameters from among the displacements (X0, Y0), angle (Phi) of rotation, and relations (R) axes. In addition, there are nine coefficients of the Fourier series for the vertical component of the Mz. Then if necessary the process is repeated until the calculation (block 666) optimized value of the declination at the location.

[150] In Fig. 18 graphically illustrates these stages. The initial horizontal counts Mx, Mythe magnetometer is shown by the ellipse 690 horizontal field, and the data about the pitch and roll from block 560 inertial measurements is shown by the circle 692. If there is no distortion,�izontally counts M x, Mythe magnetometer when 360° is represented by the circle in the horizontal plane Mx/Mycentered about (0, 0). Of course, under the influence of an external magnetic field, as a result of the effects of magnetically hard and magnetically soft iron counts Mx, Mymagnetometer 550 will be distorted and deviates from the ideal. In General, the effects of magnetic solid iron cause the shift of samples Mx, Myfrom the center (0, 0). Therefore the original samples Mx, Mythe magnetometer is shown as an ellipse 690, shifted from the center. For its part, the effects of magnetic soft iron lead to deformation perfect circumference of samples Mx, Myto a more elliptical shape. Therefore the original samples Mx, Mythe magnetometer is shown by the ellipse 690. Of course, both effects can occur simultaneously, leading to distortions both result counts Mx, Myin the ellipse.

[151] When the calibration calculation data source (690) magnetometer is rotated horizontally, using the data (692) about the pitch and roll from block 560 inertial measurements. To do this, the steps use the move tool to shift ellipse (690) of the original magnetometer data to (0, 0) in the horizontal plane Mx/Myand to rotate the ellipse (690) on the angle (Phi). In addition�about, at these stages increase the minor axis b of the ellipse (690) in accordance with a specific ratio (R) (thus rounded ellipse) and turn the ellipse (690) back angle (Phi). Finally, on the steps of the method of least squares determines that is represented by a circle (696). Standard deviation (SO), described previously, in this case represented by the difference between circles (694 and 696).

D. the SECOND STAGE of the CALIBRATION PROCESS

[152] the First stage 650 calibration from Fig. 16A is sufficient to determine the azimuth relative to magnetic North. However, in the first stage 650 not carry out the compensation of the atmospheric magnetic variation Bdof the earth. To carry out its perform the second stage of calibration is shown in Fig. 16B, which interpolate the data of the magnetic Observatory, using the binding of the internal field to the evaluation of the declination during calibration. Stages stage 650 can be implemented as software or something like that in the programmable processor control unit, disclosed in this application.

[153] In this case, the control unit 510 receives (block 670) data of three-component magnetometer on the day of calibration from one or more regional magnetic observatories. In this case, when using the magnetic model (for example, the enhanced magnetic model (UMM) or similar�base) predicted declination from observatories (670) become known. For the location of calibration or area of exploration during this process can have multiple observatories (670) associated with the location of the calibration.

[154] the control unit 510 subtracts (block 672) computed declination (668) interpolated from Observatory declinations (670). Fig. 16C schematically shows a vessel 30 in the area of intelligence regarding Observatory stations 670. For example, in each of the observatories (670) may be obtained from the temporal sequence of the Delta-declensions, where Delta represents a decline observed at the Observatory (670) declination minus the predicted declination today. By the weighting processing, based on the distance from the calibration (i.e., from vessel 30) to observatories (670) and is based on the relative intensities of the horizontal magnetic fields during the process of calibration is interpolated (block 674) the temporal sequence of Delta inducement for the location of the calibration.

[155] In Fig. 19 graphically illustrates these stages. Curves Delta-declination for the four observatories are represented by lines 6951-4. When performing weighting based on the distance from the calibration vessel 30) to observatories (670) and is based on the relative intensities of the horizontal magnetic fields, during the process interpolates the temporary posledovatel�of Delta inducement for the location of the calibration, which is represented by line 697.

[156] Then in the second stage of calibration from Fig. 16B is interpolated Delta-declination (668) is added to the predicted decline from the model to obtain a time sequence of declination at the place of calibration. Declination as a function of time and magnetic azimuth of the vessel 30, the above calculated, then subtracted (block 672) from Observatory time sequence to obtain corrections for the effect of declination as a function of azimuth. This amendment is determined (block 674) as a function of the magnetic azimuth deflection curve of the fourth order Fourier series (also called the deflection curve) by using the method of least squares. The result is to obtain the nine coefficients of the Fourier series for the correction for the influence of the declination, which is compensated by atmospheric variation of the declination at the time and place of calibration.

[157] Finally, after the calibration of the calculation control unit 510 sends (block 676), various parameters of declination for use in the processing of data collected in the process of exploration. Options include:

- the parameters of magnetically soft iron, that is, 9 the coefficients of the Fourier series for the vertical component of the Mzthat is offset by the induced magnetism (magnetic soft iron) vertically;

- options �Agnano-solid iron that is, the correction factor Mz0adjthat in combination with the Fourier series for the vertical component of the Mz(above) forms a component of Mz0to compensate for residual magnetism (magnetic solid iron) vertically;

matrix displacement X0to move in the X direction of the horizontal field;

matrix displacement Y0to move in the Y direction of the horizontal field, which together with X0compensated residual magnetism (magnetic solid iron) horizontal;

- the angle (Phi) orientation, which is an ellipse Mhhorizontal field magnetometer data has horizontally;

- the ratio (R) of the major and minor axes of that ellipse has Mhhorizontal field and it together with the angle (Phi) compensates for the induced magnetism (magnetic soft iron) horizontal; and

nine of the coefficients of the Fourier series for the correction for the influence of the declination (also called deflection curve), which is compensated by atmospheric variation of the declination at the time and place of calibration.

2. The SEQUENCE of ACTIONS WHEN PROCESSING

[158] In the presence of calibration parameters, the control unit 510 may then process the data on the decline in the vessel 30 to adjust the readings on the compass for the current decline. Fig. 20 shows a block diagram�sequence of actions in this treatment, which is used in many stages from previously outlined. As before, the processing may be implemented as software or something like that in the programmable processor control unit, disclosed in this application. In this case, when processing the previously received parameters declination defined in the calibration process, are used to find the exact magnetic declination for cable compasses and sensors and for presenting the navigation control system components.

[159] First, the control unit 510 calculates (block 702) MzFthe original azimuth Mz, Mz0adj, angle of pitch, roll, and nine Fourier coefficients for vertical parameters of magnetically soft iron and rotates (block 704) Mx, My, MzFhorizontally with regard to pitch and roll. Block 510 moves (block 706) horizontal components of Mx/My(that is, the ellipse of Mhhorizontal margins) to (0, 0) with transformation X0and Y0and rounds (block 708), the ellipse Mhhorizontal field based on the previously defined angle (Phi) and relations (R). Then, the control unit 510 calculates (block 710), the magnetic azimuth of Mxand Myand calculates (block 712) magnetic declination azimuth and the rate determined using GPS/inertial unit of measurement.

[160] To finish� the second part of the process and to take into account magnetic barometric changes B d, control unit 510 calculates (block 714) Delta-declination magnetic azimuth and nine Fourier coefficients to correct for the influence of atmospheric changes. Finally, the control unit 510 adjusts (block 716) magnetic declination based Delta-declination and presents the results to the navigation system to control a towed spits and 60 for registration, enabling subsequent processing of the adjusted counts on cable compasses, described in detail in this application.

D. CORRECTION FOR DECLINE IN LAND SEISMIC EXPLORATION

[161] As disclosed in this application, the declension can be used in marine seismic exploration and particularly in the exploration, when it is impractical to attach the tail buoys to the ends of the cables towed KOs, for example, in areas covered by ice, in areas of intensive navigation and for applications in which the cable is towed too deeply immersed, so that in practice it would be possible to attach the tail buoy (in the case of the geometry of deep-towing, oblique geometry of the cable, etc.). However, the declension can be used in other situations. In the General case of an open system can be used for marine seismic exploration, a time when a compass or other magnetic sensors of course requires additional accuracy even if you may not be an obstacle for logistics tail buoy, to get GPS readings on closed course. In addition, an open system can be used for marine seismic exploration when exploration intersects a wide area and thus is expected to change in magnetic variation or ambient conditions indicate the fluctuations of the declination.

[162] Instead of marine applications system declination can also be used in multi-component ground-based exploration, when the main orientation sensor is a compass or other magnetic directional sensor, and sometimes can be used when the earth's magnetic field is in a state of extreme changes in space or in time (for example, on the Arctic latitudes during solar storms). Therefore, an open system can be used for the data acquisition for real-time measurements of magnetic declination in a given area. In addition, an open system can be used for land and marine seismic exploration with regard to any magnetic exchange device for correcting for the influence of true North and can be used to compensate for the magnetic effects of marine or land-based device, such as a steel platform, vessel, machine or something like that. In one example, a ship, a land vehicle may have m�gitomer, navigation device and a controller, similar to that disclosed above for naval intelligence, although used for surface exploration.

[163] as another example in Fig. 21 schematically shows a plan view of a system 800 terrestrial seismic exploration, having a source 810, a plurality of sensors 820 and a Central controller 830. As spaced sensors 820 arranged in a matrix designed to extract geophysical information can be used three-component sensors for receiving energy in three dimensions, known as seismic wave in three dimensions, and they may include accelerometers, geophones speed or something like that. When using a seismic source 810 transmits acoustic energy into the ground, and sensors 820 are taking energy after reflection and refraction at the boundaries of underground structures. The Central controller 830 receives seismic and processes information so that you can receive information in the form of images.

[164] As shown, various isogonal line of the declination of the geomagnetic field can pass through the area of intelligence. These isogonal lines is usually expressed in degrees in the correction of the readings on the compass for the influence of true North. The degree isogonal lines change throughout places and also changed in time�Yeni. Therefore, measurements of the geomagnetic field from compasses or the like, associated with each of the sensors 820 may have errors due to fluctuations of the declination. For this reason, in the system 800 uses the methods disclosed in this application are intended for receipt of the declination in time and space for different sensor locations so that appropriate measurements of the geomagnetic field can be adjusted and corrected measurements may provide more correlated information to construct the image.

[165] As was also shown a decline in the sensors 820 may be defined in accordance with the interpolation from one or more remote base stations S1 to S2, so that spatial and temporal correction for the influence of declination can be calculated for different locations of the sensors when using the reference to the place, described in detail earlier. In addition or alternatively declination on the sensors 820 can be calculated individually using the system of declension and methods disclosed in this application, so that individual geomagnetic readings at different locations of the sensors can be corrected for the influence of the declination in real time.

[166] the Methods of the present disclosure can be implemented in digital electronic� schemes or in computer hardware, firmware, software, or in combinations of them. Installation for the practical application of the disclosed methods can be implemented as a computer program product, really contained in computer-readable memory device and intended for execution by a programmable processor; and the steps of the disclosed methods may be performed by a programmable processor executing a program of instructions to implement the functions of the disclosed methods by executing operations on input data and generating output data. Suitable processors include, for example, microprocessors General and special purpose. Typically, the processor accepts commands and data from a permanent storage device and/or online storage device, including magnetic disks such as internal hard disks and removable disks; magneto-optical disks; and optical disks. The memory device is really suitable for holding computer program instructions and data include all forms of nonvolatile memory, including, for example, semiconductor memory devices such as programmable read only memory, electrically erasable programmable read only memory and flash memory; mA�netic disks, such as internal hard disks and removable disks; magneto-optical disks; and CD-ROMs, read-only. Any device mentioned above can be supplemented with a specialized integrated circuit (SIS), or included in it.

[167] the above description of preferred and other embodiments is not assumed setting limits or limits the extent or scope of the concepts of the invention proposed by the applicant. The ideas of the present disclosure can be used in two -, three-and four-dimensional seismic surveys in water with ice or obstacles, as well as in conventional marine seismic and geological conditions. Although the use described for the sea, the correction magnetic declination for true North, disclosed in this application can be used in land and marine seismic exploration. In addition, aspects and methods discussed in conjunction with one particular variant of implementation, the implementation or the arrangement disclosed in this application can be used or combined with aspects and methods described in other embodiments disclosed in this application. In return for the disclosure of the concepts of the invention contained in this application, the applicant wishes to have all patent rights afforded by the appended claims of the invention. So pre�relies, that the attached formula of the invention includes all modifications and changes that fall in the scope of the following claims or equivalents.

1. Method of seismic exploration, comprising stages on which:
to calibrate the declinometer on the vessel in the area of intelligence;
receive one or more seismic signals with one or more seismic sensors in the area of exploration by towing one or more seismic sensors during a seismic survey with the help of the ship;
receive one or more dimensions of the local geomagnetic field related to one or more seismic sensors during a seismic survey;
measure the temporal and spatial parameters of the declination with the use of calibrated declinometer during the seismic survey;
adjusting one or more dimensions of the local geomagnetic field based on the settings of the declination; and
compare one or more of the adjusted measurements of the geomagnetic field with one or more seismic signals.

2. Method of seismic exploration, comprising stages on which:
receive one or more seismic signals with one or more seismic sensors in the area of exploration by towing comme� or more seismic sensors during a seismic survey with the vessel;
receive one or more dimensions of the local geomagnetic field related to one or more seismic sensors during a seismic survey;
measure the temporal and spatial parameters by measuring the declination declination on the vessel: a time during seismic surveys and compensate the influence of the parameters of the hard and soft iron of the ship for the vertical and horizontal planes in the geomagnetic field;
adjusting one or more dimensions of the local geomagnetic field based on the settings of the declination; and
compare one or more of the adjusted measurements of the geomagnetic field with one or more seismic signals.

3. A method according to claim 1 or 2, wherein the measurement of temporal and spatial parameters of the declination includes obtaining one or more baseline measurements of the geomagnetic field from one or more locations of base stations and the interpolation of temporal and spatial parameters of the declination on the basis of them.

4. A method according to claim 3, wherein one or more locations of base stations spatially separated from one or more measurements of the local geomagnetic field and in which one or more basic measurements of the geomagnetic field are continued in time.

5. FPIC�according to claim b 1 or 2, wherein the receiving one or more seismic signals with one or more seismic sensors includes towing at least one towed spit, having one or more seismic sensors behind a vessel.

6. A method according to claim 1 or 2, wherein the measurement of temporal and spatial parameters of the declination includes obtaining measurements on the basis of global positioning system on the vessel, and determining a geodetic bearing of the vessel on the basis of them.

7. A method according to claim 5, wherein the obtaining one or more measurements of the geomagnetic field related to one or more seismic sensors includes obtaining one or more samples on the compasses on at least one towed spit.

8. A method according to claim 1, wherein the measurement of temporal and spatial parameters of the declination contains the measurement of the declination on the Board at the time in the process of seismic exploration.

9. A method according to claim 1, wherein the measurement of the declination of the ship contains the calibration of the declinometer on the vessel by passing the calibration of the route with the declinometer in the area of intelligence.

10. A method according to claim 2, wherein the measurement of the declination of the ship contains the calibration of the declinometer on the vessel by passing the calibration of the route with the declinometer in the area of intelligence.

11. Method �about p. 9 or 10, in which the calibration of the declinometer on the vessel contains the replenishment calibration of one or more predicted declinations for the area of intelligence, interpolated into one or more base stations.

12. A method according to claim 9 or 10, in which the calibration of the declinometer on the vessel contains:
the passage of the vessel route in the geomagnetic field;
obtaining a plurality of magnetometer measurements when a route;
the receipt of multiple exchange measurements during the passage of the route;
the calculation of the declination in the geomagnetic field by using the magnetometer measurements and directional measurements;
the compensation effects of magnetically soft and magnetically hard iron of the vessel by simultaneous determination of the parameters of the soft and hard iron by calculation by the method of least squares; and
correction computed declination on the basis of parameters of magnetically soft and magnetically hard iron.

13. A method according to claim 8, in which the measurement of the declination on the vessel contains a compensation of at least one effect of an iron vessel to one or more dimensions of the local geomagnetic field.

14. A method according to claim 13, in which compensation includes compensation parameters magnetically soft and magnetically hard iron vessel for the vertical and horizontal planes in geomagic�Ohm field.

15. A method according to claim 2 or 14, in which the compensation parameters of magnetically soft and magnetically hard iron vessel for the vertical and horizontal planes in the geomagnetic field contains:
simultaneous determination of the parameters of the magnetically soft and magnetically hard iron by calculation of least-squares.

16. A method according to claim 1 or 2, further comprising:
at least periodic monitoring absolute position of at least one towed spit; and
match one or more of the adjusted measurements of the geomagnetic field with an absolute position.

17. A method according to claim 16, wherein at least periodic monitoring absolute position of at least one towed spit contains periodic conversion device to at least one towed spit to the surface, and
obtaining information about the absolute position of at least one towed spit when bringing it to the surface.

18. A method according to claim 17, wherein the tracking of the absolute position of at least one towed spit contains:
getting information about the relative position of the at least one towed spit when towing it below the surface of the water; and
the determination of the absolute position of at least one towed spit when you use�provided information about the relative position and periodically received information about the absolute position.

19. A programmable storage device having program commands stored in it, to encourage the programmable control device to perform a method of monitoring ice hazards to the target marine structure according to claim 1 or 2.

20. Installation for recording seismic data that contains:
at least one seismic sensor for measuring one or more seismic signals in the exploration area during the seismic survey;
at least one geomagnetic directional device associated with at least one seismic sensor to perform one or more measurements of the local geomagnetic field during the seismic survey;
declinometer, located on the vessel for measurement during the seismic survey;
a controller functionally associated with at least one seismic sensor, at least one geomagnetic exchange device and the declinometer, wherein the controller is arranged to:
calibration of the declinometer on the vessel in the area of intelligence;
determine temporal and spatial parameters of the declination from measurements made using a calibrated declinometer;
adjust one or more local measurements of the geomagnetic field based on the settings of the declination; and
with�the abandonment of one or more of the adjusted measurements of the geomagnetic field with one or more seismic signals.

21. Installation for recording seismic data that contains:
at least one seismic sensor for measuring one or more seismic signals in the exploration area during the seismic survey;
at least one geomagnetic directional device associated with at least one seismic sensor to perform one or more measurements of the local geomagnetic field during the seismic survey;
declinometer, located on the vessel for measurement over time during the seismic survey;
a controller functionally associated with at least one seismic sensor, at least one geomagnetic exchange device and the declinometer, wherein the controller is arranged to:
determine temporal and spatial parameters of the declination of the measurements made using the declinometer;
compensate the effect of the parameters of the soft and hard iron vessel for the vertical and horizontal planes in the geomagnetic field;
adjust one or more local measurements of the geomagnetic field based on the settings of the declination and of the parameters of the hard and soft iron of the ship; and
mapping one or more of the adjusted measurements of the geomagnetic field with one or more seismic �ignorami.

22. Apparatus according to claim 20 or 21, in which to determine the temporal and spatial parameters of the declination the controller is configured to receive one or more basic measurements of the geomagnetic field from one or more locations of base stations and the interpolation of temporal and spatial parameters of the declination on the basis of them.

23. Apparatus according to claim 20 or 21, in which to determine the temporal and spatial parameters of the declination the controller is configured to obtain measurements on the basis of global positioning system on the vessel, and determining a geodetic bearing of the vessel on the basis of them.

24. Apparatus according to claim 20 or 21, in which to determine the temporal and spatial parameters of the declination the controller is configured to measure the declination on the Board at the time in the process of seismic exploration.

25. Apparatus according to claim 20, in which to determine the temporal and spatial parameters of the declination the controller is configured to perform measurement using the declinometer with the passage of the calibration route with the declinometer in the area of intelligence.

26. Apparatus according to claim 21, in which the measuring vessel with the help of the declinometer on the vessel, wherein the controller is configured to calibrate the declinometer on the vessel by means of passing calibrate�owocnego route with the declinometer in the area of intelligence.

27. Apparatus according to claim 25 or 26, in which to calibrate the declinometer on Board the controller is configured to replenish the calibration of one or more predicted declinations for the area of intelligence, interpolated into one or more base stations.

28. Apparatus according to claim 25 or 26, in which to calibrate the declinometer on Board controller arranged to:
obtaining a plurality of magnetometer measurements during the passage of the route in the geomagnetic field with the ship;
the receipt of multiple exchange measurements during the passage of the route;
the calculation of the declination in the geomagnetic field by using the magnetometer measurements and directional measurements;
the compensation of the effects of hard and soft iron of the ship by simultaneous determination of the parameters of the soft and hard iron by calculation by the method of least squares; and
correction computed declination based on the parameters of the soft and hard iron.

29. Apparatus according to claim 24, in which to measure the declination on Board the controller is configured to compensate the impact of at least one of the parameters of the hard and soft iron of the ship for one or more measurements of the local geomagnetic field.

30. Apparatus according to claim 29, in which to compensate the controller is configured to compensate the options soft & TV�jogo iron vessel for the vertical and horizontal planes in the geomagnetic field.

31. Apparatus according to claim 29, in which compensation for the parameters of the soft and hard iron vessel for the vertical and horizontal planes in the geomagnetic field, the controller is configured for the simultaneous determination of the parameters of the soft and hard iron by calculation by the method of least squares.



 

Same patents:

FIELD: physics; geophysics.

SUBSTANCE: invention relates to geophysics and can be used in seismic exploration to detect oil and gas deposits. The invention discloses a method and an apparatus for marine seismic survey using one or more movable marine seismic vibrators. The sweeping function for the vibrator is based on the criterion of allowable degradation and is a nonlinear function which performs frequency sweeping from top downwards. The obtained data can be used directly without cleaning or can be easily cleaned.

EFFECT: high accuracy of survey data.

21 cl, 11 dwg

FIELD: physics, geophysics.

SUBSTANCE: invention relates to geophysics and can be used for sea seismic works. Claimed are seismic streamer and related method of evaluation of the shape of seismic streamer controlled in transverse direction. This seismic streamer is divided into several adjacent sections of seismic streamer by control devices in transverse direction. Heading transducers arranged fore and aft of every section generate the data on heading. Every section is simulated as a rectangular fore and curved fore section. Section shape is evaluated in compliance with this model from the data on heading towards the section.

EFFECT: higher precision of trial data owing to precision of seismic streamer shape evaluation.

19 cl, 2 dwg

FIELD: physics.

SUBSTANCE: disclosed is a small-size bottom seismic module, connected by a hydroacoustic link to a control station and consisting of a sealed housing, a hydrophysical module, a device for detecting geophysical signals, which includes a bottom seismometer, information storage means, a spatial orientation sensor, a radio buoy, a ballast, a ballast release, a release timer, a flash beacon, a radio beacon, an external communication socket and a power supply. The sealed housing has the shape of a hemisphere which is linked to the base of the sealed housing which is in the form of a plate, on the upper diameter of which there are mechanical elements of the ballast release, which are in the form of straps which are linked to the ballast, tightly adjoining the base of the sealed housing on its lower diameter. The means of communicating with the control station are in the form of a single-relay hydroacoustic link. The spatial orientation sensor consists of an electronic 3D compass, three accelerometers and three angular velocity measuring devices, rigidly linked to the bottom seismometer, and the bottom seismometer is in the form of a wideband molecular-electronic sensor.

EFFECT: high reliability of detected seismic signals.

3 dwg

FIELD: physics.

SUBSTANCE: acoustic signal is emitted toward sea bottom. Signal of sound reradiation from water column is received. Gas flares are isolated from receive signal. Gas flare inclination is used to evaluate the stream velocity profile and direction. Density of gas flare sources on sea bottom and methane flow direction in water for every flare are calculated. Obtained data allows the determination of methane concentration in water column in the area of methane discharge.

EFFECT: higher efficiency and accuracy of evaluation.

1 dwg

FIELD: instrumentation.

SUBSTANCE: offered invention relates to measuring equipment and can be used for development and manufacture of oceanological multichannel information and measuring complexes and development of new measuring oceanological channels. The hydrological-optical-chemical complex contains a unit of hydrophysical measuring channels, a central controller, the first and second modems of the electric communication line, a conducting rope with electric and fibre-optical communication lines, a rotating electric transition, an electric winch, an operator workstation, a unit of optical measuring channels, and a unit of normalising controllers is added to it, and each hydrophysical measuring channel through the corresponding normalising controller is connected to the central controller, besides, the first and second multiport optical modems and the rotating optical transition are added, and each optical measuring channel is connected to the corresponding input of the first multiport optical modem connected through the fibre-optic communication line of the conducting rope to the rotating optical transition connected to the second multiport optical modem connected to the operator workstation. The information from the measuring channels of the hydrophysical module is processed by the normalising controllers, and in compact way by the central controller through the multiport modem is transferred to the onboard device of the probe, and also in creation of conditions for development, manufacture, laboratory and natural studies of new optical measuring channels for identification and registration of quantity of a mineral suspended matter and the weighed organic substance in sea water, integration of currently existing measuring oceanologic channels, creation of the combined channel of the electric and fibre-optical communication line between submersible and onboard devices.

EFFECT: integration in a single hydrological-optical-chemical complex of all available measuring channels of oceanological parameters.

1 dwg

FIELD: radio engineering, communication.

SUBSTANCE: invention relates to hydroacoustic equipment and to the creation of deployment-retrieval devices (DRD) of flexible extended trailing antennas (FETA) on submarines and on surface ships. The invention proposes a DRD structure in which the deployment of the antenna to the stream in case some part of the antenna is wound on a winch, and its other part is arranged in a tubular storage unit, is provided by the creation of excess pressure in the tubular storage unit by means of a centrifugal pump, a sealing device on the end face of the tubular storage unit, which is close to the winch, is made in the form of a cylindrical module of the same inner diameter as the tubular storage unit, which is rigidly and tightly attached to it, and the suction pipeline of the centrifugal pump is made of two branch pipes, one of which is directed outboard and the other one is tightly attached to the inner volume of the tubular storage unit with an additional conical flange coaxial to the tubular storage unit and installed near its fore end face between the conical flange connected to the pressure pipeline and the sealing device of the fore end face of the tubular storage unit, the conical flange of the pressure pipeline is oriented with its constriction to the aft part of the tubular storage unit, and the conical flange of the suction pipeline is oriented with its constriction to the fore part.

EFFECT: increasing the safety of deployment and retrieval of flexible extended trailing antennas, some part of which is wound on a winch of deployment and retrieval devices, and some part is located in the tubular storage unit, without its damages or stops.

1 dwg

FIELD: measurement equipment.

SUBSTANCE: invention relates to devices for measurement of geophysical parameters in bottom area of seas and oceans. Substance: seismic module comprises a tight body (1), inside of which there is a hard disk drive (5), a unit (7) of a hydroacoustic communication channel, a ballast (2) breaker (8), a timer (9) of the breaker (8) of ballast (2), a flashing beacon (10), a joint (11) of external communication, a source of power supply (12), a hydrophysical module (13), a radio beacon (14), a seismic sensor (15), a unit (20) of spatial orientation. Besides, the unit (20) of spatial orientation comprises an electronic 3D compass, three accelerometers and three meters of angular speeds rigidly coupled with the seismic sensor (15). The seismic detector (15) is made in the form of a wideband molecular-electronic sensor. The tight body (1) is made in the form of a hemisphere with a base in the form of a plate, along the upper diameter of which there are mechanical elements of the ballast (2) breaker (8) installed. Mechanical elements of the ballast (2) breaker (8) are made in the form of slings (3), which are coupled to ballast (2) and tightly adjoin the base of the tight body (1) along its lower diameter. The hydroacoustic communication channel for connection of the seismic module with the dispatching station is made as single-relay.

EFFECT: increased validity of recorded data.

3 dwg

FIELD: transport.

SUBSTANCE: invention relates to ship building, particularly, to surface scientific and research vessels. Scientific and research icebreaking vessel is proposed for carrying out 3D seismic technology exploration irrespectively to ice conditions which vessel has a hull where seismic equipment is located, as well as a shaft for bay cable laying. To move source of acoustic waves untethered unmanned submersible is used which bases on a vessel and is dropped and lifted via separate vertical shaft using running - pulling tool.

EFFECT: improved operational performance of scientific and research vessel for seismic exploration.

3 cl, 1 dwg

FIELD: physics; geophysics.

SUBSTANCE: invention relates to geophysics and can be used in marine seismic prospecting. Disclosed is an underwater seismic recording system for reducing noise in seismic signals caused by reflected ghost waves or movement through the water. The system comprises two motion sensors. One sensor has a first response and sensitivity to noise caused by movement of the platform, as well as to acoustic waves. The second sensor has a different structure, which insulates the sensor from acoustic waves such that the response is primarily associated with noise caused by movement. Output data of the responses of the two sensors are combined to eliminate the effect of the noise caused by movement. Upon further combination with a hydrophone signal, noise caused by reflected ghost waves is reduced.

EFFECT: high accuracy of prospecting data.

14 cl, 19 dwg

FIELD: physics.

SUBSTANCE: disclosed is a method for marine seismic survey using one or more marine seismic vibrators. The vibrator sweep function is based on a quality requirement, which may be a final image quality requirement or an environmental requirement. The sweep function may be nonlinear and the energy spectrum may not match the energy spectrum of an airgun.

EFFECT: high accuracy and reliability of survey data.

24 cl, 7 dwg

FIELD: measurement equipment.

SUBSTANCE: electromagnetic waves are radiated and the signals reflected from boundaries of interface of layers of the probed medium then the results of measurements are processed. The structural maps of a dome, and also temporary seismic sections of the reflected boundaries of the top part of the sedimentary cover are pre constructed, the materials of geophysical surveys of wells, core materials are studied. The lines of profiles are marked on the surface taking into account the structural maps of the dome and temporary seismic sections of the reflected boundaries of the top part of the sedimentary cover. Lines of profiles are drawn in mutually perpendicular directions through the drilled wells with passing outside the dome contour no less than by 500 m. The coordinates of extreme and critical points of lines of profiles are added into the database. The possible external disturbance are considered, the necessary corrections of coordinates of lines of profiles are added. The lines of profiles are located, the altitude and coordinate points of study are determined. Test studies are conducted in one line of profiles. The duration of record of the reflected wave of measurement of set of the electromagnetic signals registered in a reception point during the pre-set time after the radiation of electromagnetic wave as exceeding a double transit time of an electromagnetic wave to the deepest object of studies is assigned experimentally. On the basis of data on depths and supposed or in advance known values speeds of propagation of electromagnetic waves in the medium received during the analysis of geophysical surveys and core materials the fixed time during which the receiver receives the reflected signals is selected. The sampling step is selected sufficient for the detailed description of the electromagnetic reflected signal in a quantity from 10 to 20 points for the central frequency period. During field observations the radiation of electromagnetic waves from the 10 MW transmitter and reception of the reflected signal is performed consistently by three antennas at three frequencies: 50 MHz, 25 MHz and 10 MHz in the linear and logarithmic modes of record and registration with a step 4-6 m. The impulse received at the highest frequency is considered as reflecting the detailed nature of studies and high resolution, and at the lowest frequency - as the maximum depth of sounding. In the linear mode of impulse registration the reflected signal of the lower part of the section is separated and digitised. In the logarithmic mode the registration of "desensitisation" of high amplitude of a signal and amplification of low amplitude record of the top part of the section is performed. As a result of processing of field materials the temporary sections are constructed on which the wave picture displays the features of the geological structure and composition of rocks. By change of properties of dielectric permeability the boundaries of the interface of layers and the diffracting objects in the fields of electromagnetic waves pre-determined by an axis of phase synchronism of the reflected waves are separated. For visualisation the separation of the return reflection field from the set of the obtained data using the frequency and spatial filtration is used. The summation-subtraction function for radargrams, recorded in the linear and logarithmic modes by means of which the detailed partition of the lower part of a radarogram is achieved. For lithologic- stratigraphical binding of boundaries of the reflected waves the correction of high-speed characteristics of electromagnetic impulse and materials of geophysical surveys of wells and coring data is performed. From this the regularities in nature and distribution of an electromagnetic signal are identified. The objects with weak and transitional reflecting characteristics are separated. The search indicator of the deposit boundary on the temporary section is a reduction of time of passing of the boundary of the separated oil layer and increase of the signal amplitude with respect to indications out of the deposit. The maps of time electromagnetic impulse reflections are constructed, on the basis of which the stratigraphical surfaces of the reflecting horizons of the top part of the sedimentary cover are mapped. By changes of amplitude and sign of electromagnetic signal in various mediums over a deposit, at transition and outside the deposit the maps of oil saturated depths are constructed.

EFFECT: forecasting of deposits of superviscous oils.

11 dwg

FIELD: physics.

SUBSTANCE: method includes regional gravitational and magnetic survey, as well as magnetotelluric sounding of the territory. Zones characterised by local positive anomalies of gravitational and magnetic fields, as well as local fall of electroconductive layer under the trap-rock are identified as inflow channels of magmatic substance in plain view.

EFFECT: accurate mapping of inflow channels of magmatic substance into trap-rocks.

FIELD: physics; geophysics.

SUBSTANCE: invention relates to geophysics and can be used to measure geophysical and hydrophysical parameters in near the bottoms of seas and oceans. The underwater observatory (1) comprises a seismometer consisting of seismic and seismoacoustic modules, a hydrophysical module, a magnetic field sensor, a hydrochemical measurement unit, a methane detector, a pressure sensor, a spatial orientation sensor, a nuclear magnetic resonance sensor, side-looking sonar, connected to a recording and control unit, as well as means of communicating with shipborne equipment, a ballast and a ballast opening switch. The underwater observatory (1) is in the form of a vertically profiling module placed on a moving line (2) between an upper buoy (3) and a lower buoy (4). The moving line (9) is tied through an anchored unit (5) to the ballast (6), and a supporting unit (7), mounted on a sea terminal (8) is connected to a windlass (10), mounted on the sea terminal (8).

EFFECT: broader functional capabilities and high reliability during operation.

2 dwg

FIELD: oil and gas industry.

SUBSTANCE: multifrequency-phase sounding method includes an impact by an electric field and a seismic wave on oil and gas deposits (OGD), in result the electric polarisation and movement of oil and gas fluid particles is initiated in a reservoir rock thus forming an electromagnetic field (OGD-response) adequate to the above impact. Parameters of the OGD-response are measured and recorded; the above parameters reflect the changes in phase-frequency characteristics of the seismic wave spectrum when the wave passes through OGD thus enabling the recording of the OGD availability and determination of their characteristics.

EFFECT: improved efficiency and probability of the proved detection of oil and gas deposits.

12 cl, 21 dwg

FIELD: physics.

SUBSTANCE: anchored profiling underwater observatory is linked with a control station and consists of: a subsurface buoy anchored by a steel buoy line which serves as the moving line for the profiling carrier, having a set of measuring sensors, a central microcontroller unit, an electric drive, and which moves on the moving line; a system for digital communication via a contactless inductive tap-in on the moving line, a surface buoy-guidepost with modems for transmission of data and telemetric information via a radio link, a hydroacoustic opening switch of the anchor ballast. On the moving line, over the hydroacoustic opening switch of the anchor ballast, there is a lower spherical buoy, having a modem for a hydroacoustic link inside it, an electric drive linked to a telescopic device, at the end of which a seismometer is mounted. The profiling carrier further includes sensors for determining content of hydrocarbons, carbon dioxide, alpha-, beta- and gamma-radioactivity.

EFFECT: improved operating conditions, broader functional capabilities of the underwater observatory.

2 dwg

FIELD: physics, acoustics.

SUBSTANCE: invention relates to marine geophysics and can be used to prospect for gas hydrates at the bottom of water bodies. An acoustic emission sensor is placed on the shore in a fault area. Daily changes in elastic vibrations of the acoustic emission are recorded. The time of maximum tidal forces in the operating area is determined from the energy of the elastic vibrations. The activation time of the fault area and the "calm" time are determined. Pulses of the magnetic component of the electromagnetic field are detected on the water surface during the activation period of the fault. Anomalies of the electromagnetic field pulses are determined. Samples are collected at the centre of each anomaly or group of identical anomalies. The samples are analysed for the presence and content of the useful component. The boundaries of the deposit are determined from the contours of the anomaly or groups of anomalies in which anomalous content of gas hydrates was detected.

EFFECT: easier prospecting for gas hydrate deposits.

FIELD: physics.

SUBSTANCE: method includes successive operations for acquiring and preparing data by a common-depth-point method, seismic logging, vertical seismic profiling, acoustic logging, gamma-ray density logging and verifying the quality of said data, and obtaining reference values of interval velocities; obtaining an initial hodograph and calculating a synthetic seismogram; performing quality control and inputting a constant time adjustment for landing on the upper reference horizon of the lithologic and stratigraphic system; recalculating the synthetic seismogram and performing quality control again; calculating and inputting an adjustment for landing on the lower reference horizon of the lithologic and stratigraphic system; recalculating the synthetic seismogram and performing quality control; transferring the point of the obtained hodograph to the nearest acoustically weak boundaries; recalculating the synthetic seismogram, followed by quality control and obtaining an apriori hodograph.

EFFECT: high reliability and accuracy of alignment of horizons of a time section and geologic marks of a well.

11 cl, 2 dwg

FIELD: physics, geophysics.

SUBSTANCE: invention relates to field of geophysics and can be used for determination of structural features, lithology and type of fluid saturation of reservoirs. According to the offered method the time-space and/or spatial - frequency data of electromagnetic measurements are obtained with the subsequent reconstruction of volume distribution of conductance of geological model of medium. Then the interval aggregate longitudinal electrical conductance of medium are calculated, the identification in the medium of reservoir beds with abnormal aggregate longitudinal electrical conductance is performed, the positions of axial surfaces of reservoir beds are determined, the thickness of reservoir beds corresponding to positions of axial surfaces is determined, the resistivity is determined using the value of interval aggregate longitudinal conductance of the film inside the bed for each point of measurements. The initial geo-electric model of medium is verified and disagreements are corrected. The variations of interval values of resistivity are determined. In the zone band of sharp decrease of specific resistance the coefficient of porosity of selected layers is determined, using which the capacity of reservoir bed, and also the nature of saturating fluid on the basis of interval resistivity ρp and petrophysical or statistical data are determined.

EFFECT: improvement of accuracy of the prospecting data.

5 cl, 8 dwg, 1 tbl

FIELD: physics.

SUBSTANCE: method includes constructing a "zero" depth model for potential ore-bearing areas based on a database of physical properties of rocks making up the model section, and materials of small-scale gravitational and magnetic exploration. The "zero" depth model is in the form of depth sections on which all detected bodies are assigned corresponding intervals of variation of density and magnetic characteristics. The depth model is interactively selected by solving a series of inverse problems. When selecting the depth mode, the shape of separate model bodies and physical parameters thereof (density and magnetisation) are varied until the calculated gravitational and magnetic fields almost match the observed fields. The obtained non-uniform distribution of rock density and magnetisation is interpreted using reference genetic models of the ore-magnetic systems, with construction of geologic-geophysical profiles. On -geophysical profiles with a sharp change or displacement of isolines of the density and magnetisation fields, large faults and regions of low-density nonmagnetic rocks are selected as residual sources of cotectic granites (sources of fluids, ore substances and energy), and off-shoots therefrom are delineated as the predicted ore deposit zones.

EFFECT: predicting a blind ore body associated with granitoids with high reliability.

8 dwg

FIELD: physics; geophysics.

SUBSTANCE: group of inventions relates to geophysics and can be used in field studies for different purposes. Each of the systems includes gravitational acceleration sensors (1-1 - 1-3) on three components, magnetic field sensors (2-1 - 2-3) on three components, ground seismic vibration sensors (3-1 - 3-3) on three components, a unit (15) for determining coordinates of the system and accurate time, and a control, processing and recording unit (11) connected to all said devices. The control, processing and recording unit (11) has a function for measuring gravitational acceleration parameters and magnetic field parameters synchronously with measurement of seismic vibration parameters. The gravitational acceleration sensors (1-1 - 1-3), magnetic field sensors (2-1 - 2-3) and ground seismic vibration sensors (3-1 - 3-3) are placed in a sensor unit (4), which also includes a temperature sensor (21). All sensors in the sensor unit (4), except the temperature sensor (21) are placed in a space whose geometric parameters are comparable with the sum of geometric dimensions of said sensors. In one version, the system includes a controllable heater (22) which maintains temperature in the sensor unit (4) using a signal coming from the temperature sensor (21). In another version, the temperature sensor (21) is connected to the control, processing and recording unit (11), which has a function for correcting measured parameters according to temperature changes in the sensor unit (4).

EFFECT: high accuracy of determining physical characteristics of investigated rock in a measurement space, smaller dimensions of the systems.

12 cl, 4 dwg

FIELD: oil and gas industry.

SUBSTANCE: method includes performing three-dimensional seismic prospecting operations, drilling wells with taking of core, electric, radioactive, acoustic and seismic logging, testing of wells. On basis of drilling data and geophysical well research standard modeling seismic and well spectral-time images of oil-productive deposits and their spectral-time attributes are determined. On basis of data of surface three-dimensional seismic prospecting in area of wells standard experimental spectral-time images of oil and gas productive porous collectors and their volumetric spectral seismic attributes are determined on basis of use of spectral-time analysis of seismic prospecting data in goal range of recording and numeric estimation of its results. Following mutual correlation of values of hydraulic conductivity and capacity is performed on basis of drilling geophysical well research data with standard modeling seismic, well time-spectral attributes and volumetric spectral time attributes on basis of seismic prospecting data from area of wells. Optimal volumetric spectral seismic attributes are selected with greatest mutual correlation coefficients. Regression dependencies of optimal spectral seismic attribute are built, or same for complex attribute, with values of hydraulic conductivity and oil and gas productive porous collectors capacity according to drilling and geophysical well research data. Along all tracks of seismic time cube spectral-time analysis is performed and its numeric spectral-time parameterization on basis of optimal volumetric spectral seismic attribute, or complex attribute, with construction of attribute cubes and their following recalculation according to regression dependencies to hydraulic conductivity cubes and capacity cubes.

EFFECT: higher reliability, higher precision.

Up!