Method of seismic survey and electrical survey data complex interpretation when searching for offshore hydrocarbon deposits
FIELD: data processing.
SUBSTANCE: invention relates to geophysics and can be useful in complex seismic data interpretation and electrical survey during search for offshore hydrocarbon deposits. Proposed method uses each time obtained results as zero approximation. At that, seismic survey plays main role in contour mappings, and electrical prospecting is in use of hydrocarbon deposit presence direct indicators. Seismic survey should be preferred in contour and horizon-oriented mappings, and hydrocarbons presence direct indicators are in electrical survey results. This requirement is included into disclosed method. Invention can be most efficiently used when searching for offshore hydrocarbon deposits during joint search by seismic survey and electric survey on same areas and/or profiles.
EFFECT: higher accuracy of obtained data by using relationship between two methods, expressed in addition of one method results with other, and obtaining not conflicting each other results.
SUBSTANCE: pulse electromagnetic field is excited in a medium in a sequential counterwise manner from two sides in respect to a probing zone. The following is measured: spatial differences of electric field potentials at the round profile of the generator-pickup cable streamer movement at its one-way movement along the profile and simultaneously at the pair sections of the profile which are symmetric in respect to the diameter passing through the centre of the generator line. The measurements are carried out by two measuring tripoles built-in in the streamer so that in the course of its circular movement the tripole centres are set at the profile in a diametrically opposite symmetric manner in respect to the generator line centre. Measurements at every pair exploration section are carried out firstly by one of the tripoles of the pair at one direction of the probing field and is repeated by the other tripole of the pair when it is in the same section but at the opposite field direction. One-sided and double-sided DNE-parameters are calculated on the basis of the potential difference measurements. Time sections of electrophysical parameters are drawn by the linear profiles formed by the combination of the probing results, at sequential round profiles, along and/or across the area of the object being explored.
EFFECT: higher productivity, efficiency and reliability of electric exploration works.
4 cl, 3 dwg
FIELD: physics; geophysics.
SUBSTANCE: invention relates to geophysics and can be used in prospecting for oil and natural gas deposits. Disclosed is an electromagnetic array configured for use in an underground borehole. The array includes a plurality of axially spaced electromagnets and is configured to generate a magnetic field pattern having at least first and second pairs of magnetically opposing poles. Passive ranging measurements of the induced magnetic field may be advantageously utilised, for example, to survey and guide continued drilling of a twin well. The electromagnetic array may also be used in active ranging. An array of permanent magnets providing a similar magnetic field pattern may also be used in active ranging.
EFFECT: high accuracy of survey data.
3 cl, 15 dwg
SUBSTANCE: invention is related to marine electromagnetic survey. Essence: six horizontal components of an electric field are used for this method. These electric field components are provided by three-pin ground electrodes of four poles connected in pairs. One of the pins of three-pin ground electrodes and pins of the other three three-pin ground electrodes form in pairs six horizontal components of electric field. Simultaneously data are recorded on change of electromagnetic field in time.
EFFECT: provision of effective recording of electric field at angle of less than 22,5 degrees in direction of activation notwithstanding orientation of the detecting station, guarantee of effective communications between source of activation field and paired pole intended to record electric field, relaxation in requirements to orientation of the detecting station and direction of movement and position for the source of activation field during data acquisition, excluding losses of electromagnetic data.
9 cl, 2 dwg
FIELD: measurement equipment.
SUBSTANCE: pickup includes an electromagnetic assembly for detection of a magnetic field, which is arranged on a pendulum. The latter is placed in a housing and suspended to its wall on a hinge. The housing wall opposite from the hinge has a shape of a semi-sphere and corresponds as to size to a spherical surface of the pendulum.
EFFECT: providing constancy of distance between the housing and the pendulum when the pendulum performs movements and lamination between them of shock-absorbing liquid.
16 cl, 3 dwg
FIELD: physics; geophysics.
SUBSTANCE: invention relates to geophysics and is intended for predicting earthquakes from change in the stress pattern in rocks in the area of the presumed centre based on anomalies of variation of the geomagnetic field. The method comprises measuring magnetic field variations at two stations - base station and working station; performing magnetotelluric sounding at the base station and the area of the second station; based on the results, selecting places for installing the second station according to the intensity of geoelectric properties of the section with the first (base) station, for example according to maximum correlation of magnetotelluric sounding graphs; detecting variations of the geomagnetic field at both stations (δT1 and δT2); calculating the difference in variations (Δ12(t)=δT1(t)-δT2(t); selecting variation anomalies, e.g. exceeding the difference Δ12≥kσΔ, where k=1,…,3, σΔ is the mean-square value excluding anomalous values, from which intensity of geodynamic processes are determined at the second station.
EFFECT: high reliability.
FIELD: physics; geophysics.
SUBSTANCE: invention relates to electrical survey by induction profiling and can be used when studying the structure of the top part of a geological section during search-mapping geoelectric survey. The method comprises using an electromagnetic field sensor and a receiving magnetic sensor aligned with the axis thereof, mounted such that in the detected signal, the contributions of the primary field of the source and the normal secondary field excited in the geoelectric section under investigation are close to zero, and the measured component of the magnetic field characterises an anomalous effect in the secondary field from the investigated inhomogeneity of the section. Profiling is carried out via horizontal shift relative to the Earth's surface of the electromagnetic field source and the receiving magnetic sensor mounted on the axis of a transmitter loop along a profile parallel to the axis of the sensor and passing across the range of the presumed conducting geologic formations with continuous or discrete detection of the anomalous component of the magnetic field. The presence and location of the geoelectric inhomogeneity is determined from the distribution thereof.
EFFECT: high information content and noise-immunity of measurements, reduced labour input of electrical survey.
FIELD: oil and gas industry.
SUBSTANCE: aeromagnetic, ground magnetic or hydromagnetic surveys of an oil-and-gas bearing area are performed. Abnormalities of a local component of a residual magnetic field are detected. Closed negative abnormalities are detected. Configuration and density of isolines of negative closed abnormalities of the local component of the residual magnetic field is assessed. Angles of inclination lines of the abnormal magnetic field are determined as per profiles passing through the closed isolines of the negative component of the local magnetic field.
EFFECT: improving search efficiency of hydrocarbon deposits.
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.
FIELD: physics, navigation.
SUBSTANCE: disclosed is a method for magnetic navigation on geomagnetic sections. In the method, navigation is carried out not by comparing the observed field with a reference field, but by correlation of constructed geomagnetic sections on said fields. Anomalies created by objects lying higher than the level of the earth's surface or the sea floor are considered interference and do not take part in the navigation process. Also, anomalies lying deeper than a given level and without a clear shape are also excluded.
EFFECT: high reliability of navigation.
FIELD: physics; control.
SUBSTANCE: disclosed is a method of monitoring variations of the Earth's magnetic field. The method comprises measuring magnetic field strength, generating a controlled compensating magnetic field whose direction is opposite that of the measured field, recording the value of the compensating field during full compensation at setup time. During the next measurements, the stored value is subtracted from the measured field and the difference is interpreted the variation of the magnetic field. The method further includes generating a stable gradient magnetic field, measuring the value of the gradient at setup time and, during the next measurements, correcting the transfer characteristic of the measuring device based on the results of change in the gradient of the magnetic field compared with the value obtained at the setup time.
EFFECT: improved objectivity of monitoring the Earth's magnetic field.
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
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
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.
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.
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.
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.
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.
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: measuring instrumentation.
SUBSTANCE: light emitting device (LED or laser) is placed into environment for temperature measurement. Wavelength λ of light emitting device is measured, and Δλ difference between measured wavelength and known emission wavelength λ0 of the same device at initial temperature T0 is determined. Ambient temperature is calculated by the formula
EFFECT: simplified method of ambient temperature measurement.