Method for determining parameters of hydraulic fracturing crack system
SUBSTANCE: method involves excitation of elastic vibrations by a vibration source in a well crossing hydraulic fracturing cracks, recording at receiving points at least in one neighbouring well of resonant vibrations emitted with a hydraulic fracturing crack system at excitation in drilling fluid of elastic vibrations, and determination of parameters of the crack system as per resonant vibrations occurring in the cracks. Excitation of vibrations in the well and their recording is performed before and after hydraulic fracturing. Besides, for each fixed source-receiver pair there formed is a difference seismic record of the records received before and after hydraulic fracturing; signals emitted by the crack system are separated on the difference seismic record, and parameters of cracks are determined as per the above signals.
EFFECT: improving reliable determination of spatial orientation of a hydraulic fracturing crack system and its dimensions.
The invention relates to methods for downhole seismic able to solve problems related to condition monitoring of hydraulic fractures fracturing by studies of seismic vibrations emitted from the cracks.
Hydraulic fracturing is an effective way to intensify the production of hydrocarbons from the drilling of the well by increasing the permeability of the productive formation after the formation of cracks geriatria.
To define the geometry resulting from hydraulic fracturing cracks and their development over time (monitoring) is currently used in various technologies and techniques. The most widely known methods of visualization of fracture, based on the registration of passive acoustic emission (SE). These methods provide an evaluation of the spatial orientation of the crack and its length during fracturing operations.
Seismic monitoring using passive solar cell, currently is developing rapidly in the world (Maxwell, S.C., Urbancic T, 2001; Kuznetsov O.L. and others, 2006). As the most promising in this regard the method based on passive location engaged in the CG-survey of the lower space areal system installed on the surface.
Known technology passive seismic "Seismology of emission centers - SLEC" to listen SE (Forge is s O.L. and others, 2006). This technology from the technology CDP-4D differs based on the use of SCS waves the possibility of continuous and unlimited in time listen to the technological processes in the geological environment. However, a disadvantage of SLEC, and any other technologies passive seismic is a low level signal, emitted directly as the object under study, for example, a crack resulting from hydraulic fracturing, and more small cracks forming in the area of high stresses in the vicinity of the edges of the crack. However, the fracture, causing the AOC operates as a pump, because when disclosed, the fluid is drawn into the cavity of the cracks, and when the collapse is squeezed out of it. From this it follows that the erection and collapse of the cavity of the cracks, which is the elastic system can be carried out more intensively with third-party seismic impact on the crack. This can be done by dipping into the well, across the fracture, the source of pulsed or continuous vibrations. The transfer of energy from a source to a crack that can operate in the mode of radiation will occur directly through the fluid contained in the well.
There is a method of determining parameters of a system of cracks is of idromassage, includes wave (acoustic) the influence of elastic waves in the reservoir through the fluid contained in the well intersecting cracks fracturing (Dyblenko VP and others, 2009). This stimulation leads, according to the authors this way, the initiation of additional fracturing and vibration hydraulic fracturing, resulting in a seismic emission (SE), which serves to register. By registering SE of three-component geophones located on the earth's surface, determine the spatial location of the vertices of the resulting cracks.
The disadvantage of this known method is the need to create large amplitude pressure required to fracture the rock, which occurs when seismic emission. It is essential that seismic emission is associated with the process of destruction and the emergence of new cracks, and not with variations of already existing cracks. In addition, the registration of the SE is on the earth's surface. At high noise level, typical for observations at the earth's surface, to distinguish the seismic signals associated with the AOC is very difficult. In addition, the use of three reception in the presence of a zone of low velocities (ZMS) may be ineffective because of the difficulties of separating the ox is using directivity of the first kind in connection with sub-vertical output rays for waves of different types and classes.
The known method and system for monitoring a fluid-filled areas in the environment based on the boundary waves propagating along the surface (EN 2327154). In this way register resonant vibrations in fluid-filled borehole, crossed by the crack when excited by any source of oscillations, and analyze the lowest resonant frequency of such oscillations. On the lower resonant frequencies determine the size of the crack. This implicitly assumes that the lowest resonant frequency of swasana with resonance oscillations due to boundary waves propagating along zapolnennoi liquid crack. However, the authors do not take into account that low-frequency resonances in the well can occur not only because of boundary waves in the fracture, but also due to the resonances of hydrovane (Stoneley waves propagating along the borehole.
Due to the large depth of wells resonant frequency of oscillation of the fluid in the well associated with hydrovane may be below or close to the lowest frequency resonances associated with the boundary waves in the fracture, and, thus, be interpreted incorrectly.
The closest technical solution (prototype) can be considered as a method and system for performing interwell studies which allow to record the seismic waves that occur when the fracture, caused by stimulation in the well, the injection of fluid into the well and other reasons, resulting in the destruction of rocks with the formation of these cracks (EN 2439621). Check microseismic oscillations of one or more multi-component sensors allows to determine the location of the fracture, as well as to judge the pressure fluctuations in the well, the geometry of the crack growth and the main direction of the stress in the layer.
The main disadvantage of the prototype is to register directly the total signal generated by the interference of the exciting signal emitted immersed in the well source, and the resonant vibrations emitted encountered in this system of hydraulic fractures. To highlight the pure resonant vibrations of this total signal is very difficult to determine the system parameters cracks on such aggregate fluctuations.
The purpose of the invention is to enhance reliability of determining the spatial orientation system of fractures and its size.
This objective is achieved in that in the method of determining parameters of a system of fractures, including the excitation of elastic waves by the vibration source in the borehole intersecting cracks fracturing, registered in points of reception of at least one neighboring squag is not resonant oscillations, emitted by a system of hydraulic fractures at excitation in the drilling fluid elastic waves, and determining the parameters of a system of cracks arising in the cracks of the resonant oscillations, excitation of oscillations in the borehole and their registration is carried out before and after fracturing. For each fixed pair of source-receiver differential form of the seismic record from records obtained before and after fracturing, differential seismoscopes emit signals emitted by a system of fractures, and these signals are judged on the parameters of the cracks. Unlike method (EN 2327254), not analyzed resonance oscillations of a fluid in the borehole that intersects the crack, and analyzes the amplitude of seismo-acoustic waves radiated by a crack in the external elastic medium under the action of the pressure source in the borehole, which it crosses, and registered in another well At this resonant frequency seismic vibrations of the emitter in the form of a system of fractures found by continuous excitation of oscillations of a fluid in a borehole in a wide range of seismic frequencies. The lower boundary of the operating frequency range of continuous oscillations excited in the liquid, take obviously less than the expected resonance frequency of the system of fractures, and its upper border, take the information, than the resonant frequency. About the size of the cracks are judged by the resonant frequencies emitted by a system of fractures. In one embodiment of the invention, the seismic vibrations emitted by a system of fractures, recorded in the wells located in different directions from a borehole intersecting cracks fracturing, and by kinematic and dynamic parameters of the registered signals are judged on parameters of a system of cracks. In another variant of the invention, the vibrations emitted by a system of fractures, register not only one of the neighboring wells, but at the point of reception located in the surface area.
The essence of the invention consists in the following.
The excitation of elastic waves in a fluid contained in the well, crossing the crack leads to the formation of intense hydrowalk affecting heterogeneity, traversed by the wellbore. Most contrast inhomogeneities are cracks fracturing, formed as a result of hydraulic fracturing. Single cracks, forming a system of closely spaced cracks, able to radiate oscillations under the influence of hydrowalk-excited vibration source, immersed in the contained in the well fluid. If fluctuations excite the source, located the hole directly in the interval, contained within the system cracks, fluctuations directly cracks occur synchronously with the excitation of oscillations of the source that triggers the acoustic emission crack. Thus the mode of excitation of oscillations of a system of hydraulic fractures from a passive enters the active mode, in which the intensity of acoustic radiation of hydraulic fracture increases. Triple check the signal in the neighboring wells, and not on the earth's surface, allows a more reliable determination of the spatial orientation system of cracks and its dimensions. The system of fractures that have a finite size and elastic properties, characterized by its inherent resonant frequency formed by the partial frequency of each of the cracks, which is included in the system of cracks. Account a priori information about the elastic properties of the rocks composing the productive horizon, and fluids contained in the cracks, allows registered resonant frequencies to judge the size of the system cracks (or one of the predominant cracks). The source of vibrations, exciting the oscillation of the crack (or cracks) as a whole, by itself radiates into the surrounding prostranstvo seismic vibrations regardless of the existence of hydraulic fractures. Therefore, by registering in other wells variations of this source before and after the formation of the deposits of hydraulic fracture you can remove fluctuations connected directly with the source of seismic records, leaving the differential records only fluctuations associated with fractures. Simultaneous registration of vibrations emitted by hydraulic fracture in wells and in surface area allows to achieve sverhsummarny effect unlike registering vibrations either in the well or in the near-surface zone. The fact that in the borehole signal is logged in the least distorted form and can be used in the subsequent processing of data downhole and surface observations. However, land registration fluctuations in the number of reception points, sufficient for solving inverse problems, to ensure is usually easier than by registering oscillations in the well to low-channel probes VSP.
The method is as follows.
In the fluid in the borehole, in which the conduct hydraulic fracturing, immerse the seismic wave source, registered, at least one of the neighboring wells, using a three-component probe VSP. Excitation and registration of fluctuations in doing so, to implement hydraulic fracturing and after him. After the formation of cracks through hydraulic fracturing each of cracks becomes a source of oscillations that are excited by exposure to hydrovane, in sbordoni source, immersed in the liquid contained in the same well.
Unlike the wave field observed prior to hydraulic fracturing, in neighboring wells will be recorded also waves emitted by the hydraulic fracture. Changing the frequency of the oscillations excited in the liquid source, in one of the neighboring wells by registering vibrations emitted by a system of hydraulic fractures, determine the resonant frequency characteristic of the cracks as Autonomous sources of fluctuations. The resonant frequency is determined by the maximum amplitude spectra of seismic wave fields, registered in the neighboring wells, related to the amplitude spectrum of the pressure registered in the borehole with a hydraulic fracture in a certain frequency range. Generated then the range of frequencies emitted by a source of continuous oscillations having a wave (acoustic) effect on crack, take such that this range is obviously contained resonant frequency inherent in the system of cracks. Thus, the radiation system of cracks will be much more intense than in the passive SE. For each fixed pair of source-receiver register vibrations to hydraulic fracturing and after him. Subtract entries from one another will get rid of the waves, not associated with a system of hydraulic fractures, enabling the t to simplify the selection of waves, excited directly by the cracks in the wave exposed to vibrations emitted by a source located in a liquid.
As sources of fluctuations in the proposed method can be used gidrodinamicheskie generators type GDV-20, GDV-30, and jet pumps. As the immersion of vibro-exciter can be used hydraulic vibrator of a known type (Turpening et al., 2000). The quality of contact of each of the devices of the probe VSP with the borehole wall must be sufficiently high to prevent parasitic oscillations of the instrument housing at the contact. This is achieved through the use of downhole devices, shoes, rigidly attached to the housing of each device (Schechtman GA, Kasimov ANO, Redekop, VA, 2012).
The selection of the signals emitted by the hydraulic fracture is through the application of standard processing procedures contained in the packets destined for the processing and interpretation of records VSP. Determination of interval velocities of propagation of longitudinal and transverse waves, and the use of data on the densities obtained in the gamma-gamma logging, will most clearly relate to the parameters of the oscillations emitted by the cracks, with the size of the fractures and their orientation in space.
Check signals generated by what resinae fracturing, in neighboring wells allows us to estimate the parameters of these signals in the least biased way. Reliable information about the parameters of these signals can be used when processing the records surface geophones recording acoustic emission simultaneously with the registration of these signals, the probes VSP (for example, when deconvolution entries received within the environment and on the earth's surface). Thus, one of the variants of the present invention is a modification in which the SE is registered wells and surface area. A significant difference of this modification from the prototype is that the elastic vibrations of the cracks formed by the src register not only on the earth's surface, but also within the environment. While the number of reception points take more than the determined parameters of hydraulic fractures. The concept of "surface" area implies in this case the upper part of the section (high frequency resolution). Immersing the geophones in shallow wells located in the high frequency resolution, it is possible to get rid of surface wave interference and microseisms, preventing selection of useful signals at the processing stage due to the limited instantaneous dynamic range of the seismic record in serial seismic acquisition equipment.
Here is an example of the model studies nocence of vibration parameters, emitted by the hydraulic fracture. This example shows the feasibility of the invention is in part the possibility of estimating the size of the crack parameters emitted by her hesitation.
On the technology itself create hydraulic fractures are filled with fluid, which is a waveguide, which can propagate acoustic energy. The main part of the energy of the acoustic field in a hydraulic fracture tolerated main symmetric fashion - wave Krauklis (Krauklis PV, 1962). In the long wavelength limit in respect of crack opening δ (δω/cf<<1) wave number wave Krauklis kKr(ω) is given by the following expression (Krauklis PV, 1962; derov were A.V., Maximov G.A., 2008)
Here ρfand cfthe indicated density and speed of sound in the liquid filling the hydraulic fracture, and through ρscsclrespectively, the density and speed of transverse and longitudinal waves in an elastic medium.
For a simple evaluation of the frequency of the resonance wave Krauklis in a hydraulic fracture can be considered the crack of disk shape with radius R, For cracks other form of assessment can also be performed, but it is significantly more difficult. The condition of radial resonance for disk cracks is:
The basis of the resultant resonance n=1 corresponds to the resonant frequency f=ω/2π
Assuming further that the characteristic aspect ratio for fractures is of the order of δ/R~10-3÷10-4for typical values of the elastic parameters of the medium, we get the following estimate:
Table 1 shows the estimation of the resonance frequency for cracks with characteristic radii and aspect ratios.
|Evaluation of the resonant frequency waves Krauklis for cracks of different sizes|
|R=1 m||R=3 m||R=10 m||R=50 m|
|δ/R=10-2||50 Hz||20 Hz||5 Hz||1 Hz|
|δ/R=10-3||20 Hz||6 Hz||2 Hz||0.4 Hz|
|δ/R=10-4||5 Hz||1.7 Hz||0.5 Hz||0.1 Hz|
Because the resonant castaline bulk longitudinal waves in an elastic medium significantly (by two orders of magnitude) exceeds the geometric size of the crack, in the distant wave zone r>>cl/f (at distances > 2 km for frequencies above 5 Hz) radiation crack at these frequencies will be mostly exclusive character, the amplitude of which can be estimated by the variance of the total volume of fluid V(t), filling the crack. The effective potential of a point source of longitudinal waves can be written in the form
Formula (5) allows us to estimate the amplitude of the longitudinal waves emitted by hydraulic fracture, because the change of volume of the liquid can easily control when it flows into the well.
In the near field wave zone r≤≤cl/f (at distances less than 1 km for frequencies below 5 Hz) radiation cracks will be anisotropic, which allows the use of this anisotropy when registering seismic fields in nearby wells to determine the orientation of cracks fracturing.
The positive effect in the present invention is achieved mainly through a transition from the Desk of passive acoustic emission fractures to register active acoustic radiation of fractures provided by wave action on cracked vibration source, immersed in the hole, crossing the crack, and also due to the fact that the registration of oscillation is carried out before and after hydrolaser the VA. The formation of Delta records from records obtained before and after fracturing greatly suppress the wave-interference is not associated with the radiation of the resonance oscillations directly cracks. Registration vibrations emitted by hydraulic fracture in adjacent wells, where the noise level is significantly lower, allowing more reliably to distinguish the signals generated by the hydraulic fracture and the kinematic and dynamic parameters of these signals to judge the size and spatial position of the cracks. The combination of downhole and surface observations allows to increase the signal-to-interference in the processing of land data by using the reference signals, which are possible to use resonant oscillations registered in the borehole in a more pure form than in the near-surface zone
The proposed method does not follow the current level of technology, and the combination of its essential features is different from the essential features of the known methods for determining system parameters of fractures.
The use of the present invention will significantly improve the efficiency of hydrocarbon production by more reliable estimates of the effects of increasing the permeability of the productive layers provided through gidron is sriva layer.
SOURCES of INFORMATION
1. The Underhill U.B., Line ST., Herez D., Fayard A. Method and system for performing interwell studies // Patent RF №243962], published on 10.01.2012
2. Derov were A.V., Maximov G.A. Excitation of hydrowalk in the borehole traversed by the final crack size under the action of external seismic waves // seismic Technology. 2008, V.4, p.60-63.
3. Dyblenko V.P., Kuznetsov O.L., Chirkin I.A., Rogacki GV, Ushakov US, Sharifullin RA Way of development of deposits of minerals extracted through wells // Patent RF №2357073 published 27.05.2009.
4. Krauklis PV ON some low-frequency fluctuations of the liquid layer in an elastic medium. "Prikl 1962, T, No. 6, s-1115.
5. Kuznetsov O.L., Chirkin I.A., Firsov Century Seismic monitoring as a tool to enhance the efficiency of oil field development // technology of fuel and energy, June 2006.
6. Segal, A., M. Thiercelin, K., Besson Method and system for monitoring a fluid-filled areas in the environment based on the boundary waves propagating along their surfaces// Patent RF №2327154 published 20.06.2008
7. Shechtman GA, Kasimov ANO, Redekop VA Downhole seismic device: RF Patent №2444030, 2012.
8. Maxwell, S.C., T.I. Urbancic The role of passive microseismic in the instrumented oil field // The Leading Edge. June 2001.
9. R. Turpening, Krasovec, M., Paulsson Century, Haldorsen, J., Greaves, R., Coates R. Imaging with reverse vertical seismic profiles using a downhle hydraulic axial vibrator // SEG 2000 Expanded Abstracts.
1. The method of determining parameters of a system of fractures, including the excitation of elastic waves by the vibration source in the borehole intersecting cracks fracturing, registered in points of reception of at least one neighboring wells resonant vibrations emitted by a system of hydraulic fractures at excitation in the drilling fluid elastic waves, and determining the parameters of a system of cracks arising in the cracks of the resonant oscillations, characterized in that, to increase the unambiguous determination of the system parameters of the fractures, the excitation of vibrations in the borehole and their registration is carried out before and after fracturing, for each fixed pair of source-receiver form a differential seismic the entry from the entries received before and after fracturing, differential seismoscopes emit signals emitted by a system of fractures, and these signals are judged on the parameters of the cracks.
2. The method according to claim 1, characterized in that the resonant frequency of the system hydraulic fractures is determined by the maximum intensity excited by a system of cracks oscillations by changing the frequency in the borehole fluctuations within the lower range excited by continuous vibrations to the upper limit.
3. The method according to claim 1, characterized in that the seismic vibrations, radiation is aimie system of fractures, recorded in the wells located in different directions from a borehole intersecting cracks fracturing, and by kinematic and dynamic parameters of the registered signals are judged on parameters of a system of cracks.
4. The method according to claim 1, characterized in that additionally at the time of registering oscillations in adjacent borehole record fluctuations at the point of reception located in the near-surface zone.
SUBSTANCE: group of inventions includes a method of extracting hydrocarbons from a subsurface region, a method of transforming seismic data paths and a method of determining a near-surface earth model of elastic shear wave propagation velocity based on the seismic data path. The invention employs seismic data, recorded preferably with a plurality of sources and receivers and a two-stage inversion technique. First, variations in surface-wave signals are decomposed (303) into surface-consistent transfer functions, preferably for each source, each receiver and each small region (301) of the surface. The transfer functions for each region are then inverted (308) to determine soil properties or near-surface properties (such as the shear modulus) as a function of depth. The method can solve for the complex multi-mode nature of the surface waves for media with vertical and lateral changes in properties.
EFFECT: avoiding errors and limits in resolution for traditional methods from misidentification of ground roll modes or from assuming laterally uniform soil properties, obtaining elastic soil properties, obtaining elastic properties as a function of depth from surface or depth profile of properties.
22 cl, 15 dwg
FIELD: oil and gas industry.
SUBSTANCE: seismic measurements are carried out by means of a CDP method on the surface area perspective in oil-and-gas-bearing respect. Processing and structural interpretation of seismic data is performed, thus obtaining structural maps of target reflecting horizons. Based on structural maps, additional build-up of two-dimensional networks of target reflecting horizons is performed. As per the received two-dimensional networks of target reflecting horizons and using a trend analysis method, build-up of two-dimensional networks a regional component is performed for each reflecting horizon. A local component is calculated. For cells of the two-dimensional network of the local component the prepared structures are localised for each target reflecting horizon at simultaneous fulfilment of two conditions: first - when the local component is larger than zero, and second - when a zero contour is closed. A sum of local component is defined for all the target reflecting horizons. With that, the local structure is considered to have been prepared for all the target reflecting horizons when the value of sum of local component is larger than zero. For allocated localised structures for each reflecting horizon there calculated is local structure amplitude and local structure surface area. Priority of readiness degree of the structure prepared for prospecting and exploratory oil and gas drilling is determined as per the value of amplitude and surface area of local structure, and namely: the higher the above local structure values, the higher the perspective of prospecting and exploratory oil and gas drilling.
EFFECT: improving geological informativity of geophysical surveys, localisation and ranging of prepared structures as to the perspective at preparation for prospecting and exploratory drilling.
FIELD: radio engineering, communication.
SUBSTANCE: disclosed is a method of detecting voids in the upper section of the earth's crust, involving measurement and detection of acoustic emission on the profile in the 0.01-500 Hz frequency range, with distance between measurement points in accordance with survey scale. Profiling is performed based on natural acoustic noise. Acoustic emission is detected at each point for at least 1 minute; acoustic emission spectra are calculated in 3-10 s in multiple time intervals; the average dominant experimental spectrum Se(f) and the mean-square deviation (σs) of the average from the three-second spectra are found. The theoretical shape of the desired objects is set and theoretical spectra S0(f) thereof are calculated. Resonance frequencies fm are determined from the function Se(f); curves of intensity of the spectral function Se at resonance frequencies fm (m=1, 2, 3) are plotted. Probable boundaries of desired objects on the profile are determined from intensity anomalies indicated by intensity of the spectral function S(fm) on the profile exceeding its average value by +Kσ, and gradients of the function S(fm). Preliminary dimensions and shape of said objects are determined from said boundaries and the given shape. Theoretical spectra are calculated, compared with experimental spectra; the most similar theoretical spectrum is found from the mean-square difference which does not exceed +Kσs (K=1-3) and the selected theoretical spectrum is identified with voids of a given shape and size.
EFFECT: detecting voids without breaching the integrity of the earth's surface.
SUBSTANCE: method involves performing geologic and seismic survey, as well as remote optical gas analysis using remote lidar. During gas analysis, a spectral image of the set of chemical components in the surface layer of the atmosphere is formed. Spatial selection of the spectral image of the area on given tracer substances is performed. The detected gas components are compared with the composition of the reference mixture of hydrocarbon components which corresponds to the geographical position of the area and the deposit. The area is mapped with spatial differentiation on the relief of the obtained spectral image of the probed area. The spectral image of the region of the authentic hydrocarbon deposit is selected on the map. A family of points with the measured concentration of heavy hydrocarbons is determined.
EFFECT: high accuracy of searching for hydrocarbons, low cost of search operations.
SUBSTANCE: according to the disclosed method, observation lines during land seismic survey have to be given on straight sections of the projection of a curvilinear well bore on the day surface.
EFFECT: high accuracy of determining the structural form of geological objects and longer tracking thereof during combined interpretation of well and land seismic survey data.
SUBSTANCE: group of inventions discloses an apparatus, system and method for seismic investigation of an underground structure by displaying seismic image data, which involves calculating, based on a set of wide azimuth data, a set of discrete data associated with an image function at a point of the seismic image. The set of discrete data can be transformed into a continuous curvilinear three-dimensional surface. The displayed set of data can be projected on a continuous flat surface. The projected data can be displayed in form of a flat disc. A plurality of continuous flat surfaces, each representing a single point of the image, can be collected to form a three-dimensional body which is a seismogram of points of the image. The three-dimensional body can be displayed.
EFFECT: high accuracy of geophysical detection during survey and extraction of oil and gas.
25 cl, 9 dwg
SUBSTANCE: seismic exploration system includes a seismic vibrator capable of exciting signals of different spectral composition with a system for generating control signals and a system for controlling the excited probing signals, a seismic station capable of correlating vibration records and converting the vibration records to impulse seismograms with a system for generating correlation signals and a system for determining parameters of control signals and means of communication between the seismic station (seismic vibrator) and the seismic vibrator (seismic station). The output of the system for controlling excited probing signals is connected through the means of communication between the seismic vibrator and the seismic station to the input of the system for generating correlation signals. The output of the system for determining parameters of control signals is connected through the means of communication between the seismic station and the seismic vibrator to the input of the system for generating control signals.
EFFECT: high accuracy and information value of seismic exploration.
SUBSTANCE: in the investigated territory, spatial distribution of flux density of total seismic energy characterising background intensity of its seismic activity is determined. At least one electromagnetic pulse emitter is placed on the investigated territory. The earth's crust on the investigated territory is exposed to electromagnetic pulses. Spatial distribution of flux density of total seismic energy during exposure is determined. A region preparing for an earthquake is selected. The rate of seismotectonic deformation of the selected region during exposure of the earth's crust is determined. Total seismotectonic deformation of the selected region is determined. The magnitude of the predicted earthquake is calculated.
EFFECT: high reliability of prediction.
SUBSTANCE: device includes: a hollow housing rigidly mounted in the bottom recess of an underwater floating vehicle, the top part of said housing having an axial hole for passage of a piston rod for cleaning the implosive chamber. The chamber is formed by an axial hole in the housing, a casing rigidly mounted in the bottom part of the housing and a bottom cover rigidly mounted in the bottom part of the casing. Windows of the chamber are made in the bottom part of the housing. The cleaning piston is composite. Its top part is rigidly mounted and tightly connected to a rod. The bottom part of the piston is mounted by a hollow sliding piece which is sealed with respect to the inner hole of the top part of the piston, the sliding piece being limited in back and forth movement by an inner shoulder in the hole of the top part of the piston. A spring-loaded clamp is rigidly attached to the bottom part of the piston inside a through-hole with possibility of interaction with a support on an axial cavity in a head which is freely mounted in the bottom part of the chamber. The axial hole of the housing, where the piston moves freely, has two rows of drainage radial holes linking it with the surrounding space: a top row at the top end of the hole, a bottom row above the windows themselves. The implosive chamber is covered at the bottom by a blind bottom with a check valve which allows liquid into the surrounding space, and has four longitudinal windows in the top part. The chamber is covered on its entire length by a reflector which forms a passage annular section whose area is not less than the cross-sectional area of the piston. The reflector is rigidly attached to a depression on the housing above the windows. The movable connection of the cleaning piston and the housing is sealed. The top part of the rod is rigidly attached to the bottom bearing of a long toggle link which is turned through a flexible coupling by a gear motor. A head is freely mounted inside the chamber under the cleaning piston with a large radial gap. The windows of the chamber are in an open position when all parts of the piston are in uppermost position.
EFFECT: achieving a continuous process of transmitting seismic pulses with the required frequency in the immediate vicinity of the bottom during underwater seismic profiling.
FIELD: measurement equipment.
SUBSTANCE: device comprises serially connected a sensitive element (2), a sensor of sensitive element displacement (3), a band amplifier (4) and a demodulator (5) connected to an analogue input (6) of the device. A generator (7) is connected to the sensor of sensitive element displacement (3) and the demodulator (5). The sensitive element (2) is connected to the environment and the medium inside a body (1). The device comprises serially connected an ADC (8), a microprocessor (9) with a digital port (10), a DAC (11), a switch (12), a summator (13), an amplifier (14) and a converter (15) of an electric signal into mechanical oscillations connected with the sensitive element. A filter (16) is connected to the demodulator (5) and the summator (13). The inlet of the ADC (8) is connected to the demodulator (5), and the switch (12) with the control input is connected to the microprocessor (9).
EFFECT: increased accuracy of measurement.
2 cl, 2 dwg
SUBSTANCE: disclosed is a method of determining properties of a permeable formation, which involves creating three mathematical models of propagation of a low-frequency pressure pulse: in a well, in a formation and in a single well and formation system. The third model is used to determine the frequency range in which the coefficient of reflection of the low-frequency pressure pulse from the formation is sensitive to a formation property. At least one low-frequency pressure pulse is generated in the well and the resultant well response is detected by at least one sensor of a liquid parameter, measured in response to the low-frequency pressure pulse. By analysing response, reflection of the pressure pulse from the formation is detected in the well response; data obtained by simulation are compared with data obtained by detecting well response, and formation parameters in the third model are adjusted so that data obtained by simulation match data obtained by detection. Formation properties are defined as parameters which provide matching.
EFFECT: high accuracy of analysis data obtained during various well operations without stopping said operations.
16 cl, 10 dwg
SUBSTANCE: disclosed is a well seismic survey method which involves detecting seismic vibrations at receiving points lying in a fixed depth interval, exciting vibrations from excitation points lying in different azimuths from the projection on the earth's surface of the centre of the depth interval at distances from the projections that are comparable with the depth interval. Excitation and detection of vibrations is carried out before and after hydraulic fracturing in the depth interval. Detection of vibrations after hydraulic fracturing is carried out with a probe with tool determination of spatial orientation of seismic receivers contained therein. Vibration excitation points are installed on a circle, the centre of which is the projection of the centre of the depth interval on the earth's surface. Configuration of non-uniformity is determined from the azimuthal change in kinematic and dynamic seismic parameters determined in the depth interval before and after hydraulic fracturing.
EFFECT: high accuracy of determining the extent of a fractured zone lying in the vicinity of the investigated depth interval.
3 cl, 1 dwg
SUBSTANCE: disclosed is a rod-shaped piezoceramic acoustic pressure radiator with a one-sided beam pattern, having a housing made of steel in form of a pipe, an activating element consisting of a plurality of piezoceramic discs placed on a tension rod which is mounted in the housing, a radiating element with a truncated cylindrical shape, a damper placed at the end of the tension rod and rigidly attached to the housing and with one end of the activating element. The piezoceramic discs of the activating element are placed on an insulating layer which is deposited on the tension rod, and are merged in at least three sections. One end radiating end is inclined to the axis of the housing at an angle ranging from 90° to 15° to form a truncated cylinder. The piezoceramic acoustic pressure radiator has a reflecting element made of steel, which has the shape of a truncated cylinder, placed in the housing, one of end of which faces the activating element, and is inclined to the axis of the housing at an angle ranging from 15° to 75°. The invention also discloses a device and a method for full-waveform logging.
EFFECT: high accuracy of probing analysed objects.
11 cl, 18 dwg
FIELD: oil and gas industry.
SUBSTANCE: system includes a ground part in the form of a ground-mounted unit of a telemetric system of an electric-centrifugal pump installation and a well part including signal transfer medium of a combined communication channel, a submersible unit of the telemetric system of the electric centrifugal pump installation, an interface unit, receiving and independent transmitting and control modules and a measuring loop. The latter includes several measuring probes arranged one after another and parallel connected via a cable communication line connected to the independent transmitting and control module. The receiving module together with the interface unit and the submersible unit of the telemetric system is attached to the base of the submersible electric motor of the electric centrifugal pump installation. Information from the measuring loop is received with the independent module. Communication between independent and receiving modules is performed by means of a wireless acoustic channel. Then, measuring information is transmitted through the submersible unit via the combined communication channel to the ground-mounted unit of the telemetric system.
EFFECT: improving reliability of the data transfer system owing to preventing cable damage situations of the measuring loop and improving the efficiency of the monitoring process owing to decreasing complexity of lowering and lifting operations at erection and removal and excluding cases of tubing seizure with a geophysical cable.
SUBSTANCE: disclosed method involves drilling at least one observation well in the vicinity of a producing well which connects the storage with the surface. At least one seismic receiver which is in acoustic contact with rocks surrounding the observation well is placed in the observation well. Hydrocarbon pressure in the underground storage is periodically reduced and increased. The seismic receiver detects seismo-acoustic signals at successive steps of reducing and increasing pressure. The longest of the durations of the first half-waves of signals detected at the pressure reduction section and durations of the first half-waves of all signals at the pressure raising section are determined. The onset of cracks near the boundary of the storage, which are capable of destroying the storage, is determined from the onset of at least one seismo-acoustic signal. The destruction of the array of rocks around the storage is indicated by the duration of the first half-wave of such a seismo-acoustic signal at the pressure raising step being shorter than the longest of the durations of the first half-waves of signals detected at the pressure reduction step.
EFFECT: high reliability of predicting destruction of an array of rocks holding an underground storage of hydrocarbons.
FIELD: oil and gas industry.
SUBSTANCE: control device of drilling parameters during drilling of an underground formation includes a drilling element; at least one acoustic signal transfer and receiving sensor in a well; downhole control device and downhole electronic device. Electronic device is provided with a processor and memory. Acoustic signals are transferred and received in the well. Received acoustic signals are processed to obtain at least one characteristic including formation movability. Fluid parameters are determined on the basis of variation of at least one characteristic. Parameter determination results are given and the decision on the well arrangement is taken based on certain parameters.
EFFECT: improving deposit development efficiency.
21 cl, 5 dwg, 2 tbl
FIELD: oil and gas industry.
SUBSTANCE: acoustic method of detection of fluid behind-casing flows location in well includes lowering and lifting of well noise signal receiver in well. During lifting curves of noise signal intensity changes are recorded, then the signal is processed using secondary equipment. Noise signal well receiver is lifted with constant certain speed V1. The receiver has highly-directional characteristic of direction, orthogonal to well axis. Output signal is processed by extraction from recorded noise signal of characteristics of receiver passing relative to location of fluid behind-the-casing flow for this speed V1.
EFFECT: simplifying implementation and improving method reliability.
5 cl, 3 dwg
SUBSTANCE: disclosed is a method of determining geometric characteristics of hydraulic fracture cracks, which involves use of natural lithological reflectors lying under artificial hydraulic fracture cracks. The method involves optimisation of the arrangement of seismic sources and receivers in accordance with the location of reflectors and the investigation zone. Through differential measurement of the tintage of the transverse wave and splitting of the transverse wave, which is achieved by subtracting the seismic signal before fracture and during fracture, the obtained seismic signal of the artificial hydraulic fracture crack can be efficiently converted to useful information on the size and shape of the crack.
EFFECT: high accuracy of determining geometric characteristics of cracks.
7 cl, 1 dwg
FIELD: oil and gas industry.
SUBSTANCE: monitoring method of axial load on bit at turbine drilling of the well equipped with drill pump, delivery line, drilling hose, gooseneck, swivel, drill column, turbo-drill, bit, with ground rejection filter additionally arranged in delivery line of drill pump, acoustically rotating rejection filter rigidly attached through shaft of turbo-drill to turbo-drill and bit, hydrophone with measuring equipment between swivel with gooseneck and drilling hose. It includes drill pump for supply of flushing fluid via drill column to turbo-drill, via delivery line, via drill column from drill pump to turbine blades of turbo-drill and brings into rotation of shaft turbo-drill rigidly connected to the bit. At that, frequency band in the spectrum generated with drill pump, ground rejection filter arranged in delivery line is converted; broad-band acoustic spectrum with constant amplitude is generated with turbine blades; broad-band acoustic spectrum is generated with impacts of teeth of roller cutters against mine rock, with varying amplitude dependent on the bit load; frequency band is converted as per amplitude from total acoustic spectrum consisting of spectra generated with turbine blades and impacts of teeth of roller cutters against mine rock to the range of low frequencies by means of amplitude-pulse modulation with acoustic rotating rejection filter arranged on turbo-drill shaft; at the same time, monitoring of the changing bit load is performed through hydrophone connected to measuring equipment as per varying amplitude of acoustic waves converted by means of amplitude-pulse modulation of low frequency range with acoustic rotation rejection filter.
EFFECT: improving monitoring reliability of bit axial load at turbine drilling.
1 ex, 10 dwg
FIELD: oil and gas industry.
SUBSTANCE: method involves process of formation hydraulic fracturing in well including recording of microseismic activity generated during hydraulic fracturing process. Also low-frequency waves of pressure (tube waves) are generated near well. Tube waves reflected from hydraulic fracturing are recorded on-line and location of microseismic events and reflection of tube waves from hydraulic fracturing is analysed.
EFFECT: increasing accuracy of determination of initial stage of splitting and accompanying phenomena during formation hydraulic fracturing.
7 cl, 8 dwg
FIELD: well drilling, possible use for controlling number of revolutions of shaft of turbo-drill via acoustic communication channel.
SUBSTANCE: system contains face indicator of information signals, made in form of modulator shaft with through aperture, positioned in circular Helmholtz resonator with possible combination of their apertures and connected through sleeve to shaft of turbo-drill, which additionally acts as acoustic face emitter, receiver of acoustic signal, amplifier and decoding block. Helmholtz resonator is mounted with possible change of area of apertures combined with modulator-shaft to provide for absorption of energy of acoustic signal at different frequencies.
EFFECT: increased resistance to interference and precision of information transfer.
4 dwg, 1 ex