DAS microseismic focus mechanism inversion method and device, electronic equipment and medium

Abstract

The invention discloses a DAS microseismic focus mechanism inversion method and device, electronic equipment and a medium. The method comprises the following steps: picking up P-wave amplitude, calculating an amplitude correction factor, and correcting the P-wave amplitude; obtaining a P-wave radiation pattern curve according to the corrected P-wave amplitude; and according to the P-wave radiation pattern curve, inverting a fault nodal plane solution. According to the method, the propagation effect of the seismic waves, the radiation pattern of the seismic source and the direction response of the DAS to the P wave are comprehensively considered in the seismic source mechanism inversion process, so that the precision of the DAS micro-seismic seismic source mechanism inversion is improved.

Description

Technical Field

[0001] The present invention relates to the field of microseismic inversion, and more particularly, to a DAS microseismic source mechanism inversion method, device, electronic device and medium. Background Art

[0002] In the field of oil and gas exploitation, the application of microseismic monitoring technology mainly involves collecting microseismic signals generated during hydraulic fracturing to monitor the fracturing process, describe the characteristics of fracturing fractures, and evaluate the fracturing effect. The distributed fiber optic acoustic sensing technology (DAS) is based on the optical time domain reflectometry principle (OTDR). By sending laser pulses to the connected detection optical cable through a high-power laser transmitter, and simultaneously collecting and analyzing the Rayleigh scattered light in the backscattered light, the distributed perception of vibration signals can be realized, which is a new type of fracturing microseismic monitoring technology means.

[0003] Microseismic source mechanism inversion is the main method for studying the occurrence parameters of fracturing fractures. Currently, the commonly used source mechanism inversion methods inversely calculate the source mechanism by using information such as P-wave first motion polarity, P-wave amplitude, and P / S wave amplitude ratio alone or in combination. Among them, when using amplitude information, most only consider the propagation effect of seismic waves and the influence of the source radiation pattern on the P-wave or S-wave amplitude at different receiving points. DAS has obvious directional response characteristics. For P-waves, the amplitude response is the largest when the wave is incident parallel to the fiber axis direction, and the amplitude response is the smallest when the wave is incident perpendicular to the fiber axis.

[0004] Therefore, it is necessary to develop a DAS microseismic source mechanism inversion method, device, electronic device and medium.

[0005] The information disclosed in the background art part of the present invention is only intended to deepen the understanding of the general background art of the present invention, and should not be regarded as an admission or any form of implication that this information constitutes the prior art known to those skilled in the art. Summary of the Invention

[0006] The present invention provides a DAS microseismic source mechanism inversion method, device, electronic device and medium, which comprehensively consider the propagation effect of seismic waves, the radiation pattern of the source, and the directional response of DAS to P-waves during the source mechanism inversion process, thereby improving the accuracy of DAS microseismic source mechanism inversion.

[0007] In a first aspect, an embodiment of the present disclosure provides a DAS microseismic source mechanism inversion method, including:

[0008] Picking up the P-wave amplitude, calculating the amplitude correction factor, and correcting the P-wave amplitude;

[0009] Obtaining the P-wave radiation pattern curve according to the corrected P-wave amplitude;

[0010] Invert the fault plane solution according to the P-wave radiation pattern curve.

[0011] As a specific implementation manner of the embodiment of the present disclosure, picking up the P-wave amplitude includes:

[0012] Intercept the first arrival P-wave phase from the DAS microseismic monitoring record, and extract the maximum absolute amplitude value of the P-wave waveform recorded at each DAS receiving point.

[0013] As a specific implementation manner of the embodiment of the present disclosure, calculating the amplitude correction factor includes:

[0014] Use the ray tracing algorithm to calculate the propagation path of the seismic wave, and calculate the propagation path length and transmission angle of the seismic wave according to the ray tracing result, and then calculate the amplitude correction factor.

[0015] As a specific implementation manner of the embodiment of the present disclosure, the amplitude correction factor is:

[0016]

[0017] where F is the amplitude correction factor, n is the number of velocity layers, l i is the propagation path length of the seismic wave in the i-th layer of the medium, T pp (α i ) is the transmission coefficient corresponding to the transmission angle α in the i-th layer of the medium i when, R(α 1 ) is the amplitude response factor of the optical fiber when the P-wave is incident at an angle α perpendicular to the optical fiber 1 angle.

[0018] As a specific implementation manner of the embodiment of the present disclosure, obtaining the P-wave radiation pattern curve according to the corrected P-wave amplitude includes:

[0019] Calculate the relative relationship according to the corrected P-wave amplitude received by each geophone, and obtain the P-wave radiation pattern curve.

[0020] As a specific implementation manner of the embodiment of the present disclosure, inverting the fault plane solution according to the P-wave radiation pattern curve includes:

[0021] Take the P-wave radiation pattern curve as the input, and use the grid search method to perform a full-space search on the spatial parameters of the fault, calculate the objective function, and thus obtain the corresponding fault plane solution.

[0022] As a specific implementation manner of the embodiment of the present disclosure, the spatial parameters include the azimuth angle dip angle δ, and slip angle λ.

[0023] As a specific implementation manner of the embodiment of the present disclosure, the objective function is the correlation coefficient between the P-wave radiation pattern curve and the theoretical P-wave radiation pattern curve:

[0024]

[0025] where n is the number of observation channels, that is, the number of fiber optic DAS sensing points; x i and y i are respectively the picked and theoretical P-wave amplitude magnitudes corresponding to the i-th channel; and are respectively the average values of the picked and theoretical P-wave amplitude magnitudes.

[0026] In a second aspect, the embodiment of the present disclosure further provides a DAS microseismic source mechanism inversion device, including:

[0027] A correction module that picks up the P-wave amplitude, calculates the amplitude correction factor, and corrects the P-wave amplitude;

[0028] A calculation module that obtains the P-wave radiation pattern curve according to the corrected P-wave amplitude;

[0029] An inversion module that inversely solves the fault plane solution according to the P-wave radiation pattern curve.

[0030] As a specific implementation manner of the embodiment of the present disclosure, picking up the P-wave amplitude includes;

[0031] Intercepting the first arrival P-wave phase from the DAS microseismic monitoring record and extracting the maximum absolute amplitude value of the P-wave waveform recorded at each DAS receiving point.

[0032] As a specific implementation manner of the embodiment of the present disclosure, calculating the amplitude correction factor includes:

[0033] Using the ray tracing algorithm to calculate the propagation path of the seismic wave, and calculating the propagation path length and transmission angle of the seismic wave according to the ray tracing result, and then calculating the amplitude correction factor.

[0034] As a specific implementation manner of the embodiment of the present disclosure, the amplitude correction factor is:

[0035]

[0036] where F is the amplitude correction factor, n is the number of velocity layers, l i is the propagation path length of the seismic wave in the i-th layer of medium, T pp (α i ) is the transmission coefficient corresponding to the transmission angle α i in the i-th layer of medium, and R(α 1 ) is the P-wave along the direction perpendicular to the optical fiber at an angle α1 Amplitude response factor of optical fiber at angular incidence.

[0037] As a specific implementation manner of an embodiment of the present disclosure, obtaining the P-wave radiation pattern curve according to the corrected P-wave amplitude includes:

[0038] Calculating the relative relationship according to the corrected P-wave amplitude received by each geophone, and obtaining the P-wave radiation pattern curve.

[0039] As a specific implementation manner of an embodiment of the present disclosure, inverting the fault plane solution according to the P-wave radiation pattern curve includes:

[0040] Taking the P-wave radiation pattern curve as the input, using the method of grid search to perform a full-space search on the spatial parameters of the fault, and calculating the objective function, so as to obtain the corresponding fault plane solution.

[0041] As a specific implementation manner of an embodiment of the present disclosure, the spatial parameters include azimuth dip angle δ, and slip angle λ.

[0042] As a specific implementation manner of an embodiment of the present disclosure, the objective function is the correlation coefficient between the P-wave radiation pattern curve and the theoretical P-wave radiation pattern curve:

[0043]

[0044] where n is the number of observation channels, that is, the number of optical fiber DAS sensing points; x i and y i are respectively the picked and theoretical P-wave amplitude magnitudes corresponding to the i-th channel; and are respectively the average values of the picked and theoretical P-wave amplitude magnitudes.

[0045] In a third aspect, an embodiment of the present disclosure further provides an electronic device, and the electronic device includes:

[0046] A memory storing executable instructions;

[0047] A processor, and the processor runs the executable instructions in the memory to implement the DAS microseismic source mechanism inversion method.

[0048] In a fourth aspect, an embodiment of the present disclosure further provides a computer-readable storage medium, and the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the DAS microseismic source mechanism inversion method is implemented.

[0049] The beneficial effects are as follows:

[0050] In view of the directional response characteristics of the fiber optic DAS, when constructing the amplitude correction factor, in addition to considering the amplitude changes caused by the geometric spreading effect during the propagation of seismic waves and the AVO effect of layered strata, the amplitude response changes when seismic waves are incident at different angles to the optical fiber are also considered. Accordingly, the amplitude differences caused by different source radiation patterns can be more accurately restored, so as to obtain a DAS microseismic source mechanism inversion result with higher accuracy.

[0051] The method and device of the present invention have other characteristics and advantages, which will be obvious from the accompanying drawings incorporated herein and the subsequent detailed description, or will be detailed in the accompanying drawings incorporated herein and the subsequent detailed description. These accompanying drawings and detailed description are jointly used to explain the specific principles of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] By describing the exemplary embodiments of the present invention in more detail in conjunction with the accompanying drawings, the above and other objects, features and advantages of the present invention will become more obvious. Among them, in the exemplary embodiments of the present invention, the same reference numerals generally represent the same components.

[0053] Figure 1 The flowchart showing the steps of the DAS microseismic source mechanism inversion method according to an embodiment of the present invention.

[0054] Figure 2 The schematic diagram showing the ray path and transmission angle of seismic wave propagation according to an embodiment of the present invention.

[0055] Figure 3 The schematic diagram showing the fault spatial orientation parameters according to an embodiment of the present invention.

[0056] Figure 4 The schematic diagram showing the DAS microseismic synthetic seismogram according to an embodiment of the present invention.

[0057] Figure 5 The schematic diagram showing the comparison of the P-wave amplitude in the synthetic seismogram and the P-wave amplitude corresponding to the inverted source mechanism according to an embodiment of the present invention.

[0058] Figure 6 The block diagram showing a DAS microseismic source mechanism inversion device according to an embodiment of the present invention.

[0059] DESCRIPTION OF REFERENCE NUMERALS:

[0060] 201, correction module; 202, calculation module; 203, inversion module. DETAILED DESCRIPTION

[0061] The preferred embodiments of the present invention will be described in more detail below. Although the preferred embodiments of the present invention are described below, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein.

[0062] To facilitate the understanding of the solutions and effects of the embodiments of the present invention, six specific application examples are given below. Those skilled in the art should understand that these examples are only for facilitating the understanding of the present invention, and any specific details are not intended to limit the present invention in any way.

[0063] Example 1

[0064] Figure 1 The flowchart showing the steps of the DAS microseismic source mechanism inversion method according to an embodiment of the present invention is shown.

[0065] As Figure 1 shown, the DAS microseismic source mechanism inversion method includes: Step 101, picking up the P-wave amplitude, calculating the amplitude correction factor, and correcting the P-wave amplitude; Step 102, obtaining the P-wave radiation pattern curve according to the corrected P-wave amplitude; Step 103, inverting the fault plane solution according to the P-wave radiation pattern curve.

[0066] In one example, picking up the P-wave amplitude includes;

[0067] Intercepting the first arrival P-wave phase from the DAS microseismic monitoring record and extracting the maximum absolute amplitude value of the P-wave waveform recorded at each DAS receiving point.

[0068] In one example, calculating the amplitude correction factor includes:

[0069] Using the ray tracing algorithm to calculate the propagation path of the seismic wave, and calculating the propagation path length and transmission angle of the seismic wave according to the ray tracing result, and then calculating the amplitude correction factor.

[0070] In one example, the amplitude correction factor is:

[0071]

[0072] where F is the amplitude correction factor, n is the number of velocity layers, l i is the propagation path length of the seismic wave in the i-th layer of the medium, T pp (α i ) is the transmission coefficient corresponding to the transmission angle α i in the i-th layer of the medium, and R(α 1 ) is the amplitude response factor of the optical fiber when the P-wave is incident at an angle α 1 with respect to the direction perpendicular to the optical fiber.

[0073] In one example, obtaining the P-wave radiation pattern curve based on the corrected P-wave amplitude includes:

[0074] Calculating the relative relationship based on the corrected P-wave amplitude received by each geophone, and obtaining the P-wave radiation pattern curve.

[0075] In one example, inverting the fault plane solution based on the P-wave radiation pattern curve includes:

[0076] Taking the P-wave radiation pattern curve as the input, using the grid search method to perform a full-space search on the spatial parameters of the fault, calculating the objective function, and thus obtaining the corresponding fault plane solution.

[0077] In one example, the spatial parameters include the azimuth angle dip angle δ, and slip angle λ.

[0078] In one example, the objective function is the correlation coefficient between the P-wave radiation pattern curve and the theoretical P-wave radiation pattern curve:

[0079]

[0080] where n is the number of observation channels, that is, the number of fiber optic DAS sensing points; x i and y i are respectively the picked and theoretical P-wave amplitude magnitudes corresponding to the i-th channel; and are respectively the average values of the picked and theoretical P-wave amplitude magnitudes.

[0081] Specifically, the present invention is a method for inverting the microseismic source mechanism using the P-wave amplitude information in the microseismic data collected by DAS. Using the formation velocity model obtained from conventional seismic data or well logging records, combined with the microseismic event location results, the amplitude correction factor is calculated through ray tracing to eliminate the influence of seismic wave propagation effects and DAS direction responses on the first arrival P-wave amplitude. Using the grid search inversion method, by calculating the residual between the actual radiation pattern and the theoretical radiation pattern, the fault plane solution can be inverted.

[0082] Intercept the first arrival P-wave phase from the DAS microseismic monitoring record, and extract the maximum absolute amplitude value of the P-wave waveform recorded at each DAS receiving point.

[0083] Figure 2 Shows a schematic diagram of the seismic wave propagation ray path and transmission angle according to an embodiment of the present invention.

[0084] Affected by the geometric spreading effect and the AVO effect of layered formations during the propagation of seismic waves, as well as the DAS response characteristics when P-waves are incident along different directions, the amplitude of the P-waves radiated when the fracturing cracks rupture and received by DAS after propagating through the formation does not truly reflect the relative magnitude of the source energy. To accurately recover the P-wave radiation pattern of the source, it is necessary to correct the amplitude of the P-waves recorded by DAS. Based on the location results obtained from the previous location processing and the horizontal layered velocity model obtained from the acoustic travel-time logging data, the ray-tracing algorithm is used to calculate the propagation path of the seismic waves, as shown in Figure 2 shown. Calculate the propagation path length l of the seismic waves according to the ray-tracing results 1 , l 2 , l 3 , the transmission angle α 1 , α 2 , α 3 . The calculation formula for the amplitude correction factor is:

[0085]

[0086] where F is the amplitude correction factor, n is the number of velocity layers, l i is the propagation path length of the seismic waves in the i-th layer medium, T pp (α i ) is the transmission coefficient corresponding to the transmission angle α i in the i-th layer medium, and the transmission coefficient can be calculated through the Zoeppritz equation or its approximate formula. R(α 1 ) is the amplitude response factor of the optical fiber when the P-wave is incident at an angle α 1 with respect to the direction perpendicular to the optical fiber.

[0087] The P-wave radiation pattern represents the relative relationship of the amplitudes of the P-waves received by each geophone under a specific source mechanism solution. Calculate the relative relationship based on the corrected amplitudes of the P-waves received by each geophone to obtain the P-wave radiation pattern curve.

[0088] Figure 3 shows a schematic diagram of the fault spatial orientation parameters according to an embodiment of the present invention.

[0089] Taking the P-wave radiation pattern curve as the input, using the grid search method, as shown in Figure 3 shown, perform a full-space search for the three spatial parameters of the fault, the azimuth angle dip angle δ, and slip angle λ, calculate the objective function, and thus obtain the corresponding fault plane solution (fault plane and auxiliary plane). The objective function is the correlation coefficient between the picked P-wave radiation pattern curve and the theoretical P-wave radiation pattern curve:

[0090]

[0091] where n is the number of observation channels, i.e., the number of fiber optic DAS sensing points; x i and y i are respectively the picked and theoretical P-wave amplitude magnitudes corresponding to the i-th channel; and are respectively the average values of the picked and theoretical P-wave amplitude magnitudes. The solution corresponding to the maximum correlation coefficient is selected as the inversion result output. When performing microseismic source mechanism inversion using P-wave amplitude information, considering the factor of inconsistent fiber optic responses caused by different P-wave incident angles at different receiving points, a higher-precision source mechanism inversion result can be obtained.

[0092] Example 2

[0093] The present invention also provides a DAS microseismic source mechanism inversion device, including:

[0094] A calibration module that picks up the P-wave amplitude, calculates the amplitude correction factor, and corrects the P-wave amplitude;

[0095] A calculation module that obtains the P-wave radiation pattern curve based on the corrected P-wave amplitude;

[0096] An inversion module that inversely calculates the fault plane solution based on the P-wave radiation pattern curve.

[0097] In one example, picking up the P-wave amplitude includes;

[0098] Intercepting the first arrival P-wave phase from the DAS microseismic monitoring record and extracting the maximum absolute amplitude value of the P-wave waveform recorded at each DAS receiving point.

[0099] In one example, calculating the amplitude correction factor includes:

[0100] Using the ray tracing algorithm to calculate the propagation path of the seismic wave, and calculating the propagation path length and transmission angle of the seismic wave based on the ray tracing result, and then calculating the amplitude correction factor.

[0101] In one example, the amplitude correction factor is:

[0102]

[0103] where F is the amplitude correction factor, n is the number of velocity layers, l i is the propagation path length of the seismic wave in the i-th layer of the medium, T pp (α i ) is the transmission coefficient corresponding to the transmission angle α i in the i-th layer of the medium, and R(α 1 ) is the amplitude response factor of the fiber optic when the P-wave is incident at an angle α 1 with respect to the direction perpendicular to the fiber optic.

[0104] In one example, obtaining the P-wave radiation pattern curve based on the corrected P-wave amplitude includes:

[0105] Calculating the relative relationship based on the corrected P-wave amplitude received by each geophone, and obtaining the P-wave radiation pattern curve.

[0106] In one example, inverting the fault plane solution based on the P-wave radiation pattern curve includes:

[0107] Taking the P-wave radiation pattern curve as the input, using the grid search method to perform a full-space search on the spatial parameters of the fault, calculating the objective function, and thus obtaining the corresponding fault plane solution.

[0108] In one example, the spatial parameters include the azimuth angle dip angle δ, and slip angle λ.

[0109] In one example, the objective function is the correlation coefficient between the P-wave radiation pattern curve and the theoretical P-wave radiation pattern curve:

[0110]

[0111] where n is the number of observation channels, i.e., the number of fiber optic DAS sensing points; x i and y i are respectively the picked and theoretical P-wave amplitude magnitudes corresponding to the i-th channel; and are respectively the average values of the picked and theoretical P-wave amplitude magnitudes.

[0112] Specifically, the present invention is a method for inverting the microseismic source mechanism by using the P-wave amplitude information in the microseismic data collected by DAS. Using the formation velocity model obtained from conventional seismic data or well logging records, combined with the microseismic event location results, the amplitude correction factor is calculated through the ray tracing method to eliminate the influence of the seismic wave propagation effect and the DAS direction response on the first arrival P-wave amplitude. Using the grid search inversion method, the fault plane solution can be inverted by calculating the residual between the actual radiation pattern and the theoretical radiation pattern.

[0113] Intercept the first arrival P-wave phase from the DAS microseismic monitoring record, and extract the maximum absolute amplitude value of the P-wave waveform recorded at each DAS receiving point.

[0114] Affected by the geometric spreading effect and the AVO effect of layered strata during the propagation of seismic waves, as well as the DAS response characteristics when P-waves are incident in different directions, the amplitude of the P-waves radiated when the fracturing cracks rupture and received by DAS after propagating through the strata cannot truly reflect the relative magnitude of the source energy. To accurately restore the P-wave radiation pattern of the source, it is necessary to correct the amplitude of the P-waves recorded by DAS. Based on the location results obtained from the previous location processing and the horizontal layered velocity model obtained from the acoustic travel-time logging data, the ray-tracing algorithm is used to calculate the propagation path of the seismic waves, as Figure 2 shown. Calculate the propagation path length l of the seismic wave according to the ray-tracing result 1 , l 2 , l 3 , the transmission angle α 1 , α 2 , α 3 . The calculation formula for the amplitude correction factor is:

[0115]

[0116] where F is the amplitude correction factor, n is the number of velocity layers, l i is the propagation path length of the seismic wave in the i-th layer of the medium, T pp (α i ) is the transmission coefficient corresponding to the transmission angle α i in the i-th layer of the medium, and the transmission coefficient can be calculated by the Zoeppritz equation or its approximate formula. R(α 1 ) is the amplitude response factor of the optical fiber when the P-wave is incident at an angle α 1 with respect to the direction perpendicular to the optical fiber.

[0117] The P-wave radiation pattern represents the relative relationship of the amplitudes of the P-waves received by each geophone under a specific source mechanism solution. Calculate the relative relationship based on the corrected P-wave amplitudes received by each geophone to obtain the P-wave radiation pattern curve.

[0118] Taking the P-wave radiation pattern curve as the input, using the grid search method, as Figure 3 shown, perform a full-space search for the three spatial parameters of the fault, the azimuth dip angle δ, and slip angle λ, calculate the objective function, and thus obtain the corresponding fault plane solution (fault plane and auxiliary plane). The objective function is the correlation coefficient between the picked P-wave radiation pattern curve and the theoretical P-wave radiation pattern curve:

[0119]

[0120] where n is the number of observation channels, that is, the number of optical fiber DAS sensing points; x i and y iThe picked and theoretical P-wave amplitude magnitudes corresponding to the i-th trace, respectively; and are the average values of the picked and theoretical P-wave amplitude magnitudes, respectively. The solution corresponding to the maximum correlation coefficient is selected as the inversion result for output. When performing microseismic source mechanism inversion using P-wave amplitude information, considering the factor of inconsistent fiber optic responses caused by different P-wave incident angles at different receiving points, a higher-precision source mechanism inversion result can be obtained.

[0121] Example 3

[0122] Figure 4 Fig. shows a schematic diagram of a DAS microseismic synthetic record according to an embodiment of the present invention.

[0123] Figure 5 Fig. shows a schematic diagram of the comparison between the P-wave amplitude in the synthetic record and the P-wave amplitude corresponding to the inverted source mechanism according to an embodiment of the present invention.

[0124] Set the occurrence parameters of the fracturing crack to be: δ = 0°, λ = 90°, and the synthetic DAS microseismic record is as Figure 4 shown. The P-wave phase is intercepted from the synthetic record, and the source mechanism solution of this DAS microseismic event is inverted using the method proposed by the present invention. The inverted δ = 0.10°, λ = 90.28°. Figure 5 Fig. shows the comparison between the magnitude of the P-wave amplitude extracted from the synthesis and the theoretical P-wave amplitude corresponding to the inversion result. It can be seen that there is a good agreement between the two, indicating that the method of the present invention is an effective and high-precision DAS microseismic source mechanism inversion method.

[0125] Example 4

[0126] Figure 6 Fig. shows a block diagram of a DAS microseismic source mechanism inversion device according to an embodiment of the present invention.

[0127] As Figure 6 shown, the DAS microseismic source mechanism inversion device includes:

[0128] A calibration module 201 that picks up the P-wave amplitude, calculates the amplitude calibration factor, and calibrates the P-wave amplitude;

[0129] A calculation module 202 that obtains the P-wave radiation pattern curve based on the calibrated P-wave amplitude;

[0130] An inversion module 203 that inverses the fault plane solution based on the P-wave radiation pattern curve.

[0131] As an alternative, the picked P-wave amplitude includes;

[0132] Intercept the first arrival P-wave phase from the DAS microseismic monitoring record, and extract the maximum absolute amplitude value of the P-wave waveform recorded at each DAS receiving point.

[0133] As an alternative, calculating the amplitude correction factor includes:

[0134] Use the ray tracing algorithm to calculate the propagation path of the seismic wave, and calculate the propagation path length and transmission angle of the seismic wave according to the ray tracing results, and then calculate the amplitude correction factor.

[0135] As an alternative, the amplitude correction factor is:

[0136]

[0137] where F is the amplitude correction factor, n is the number of velocity layers, l i is the propagation path length of the seismic wave in the i-th layer of the medium, T pp (α i ) is the transmission coefficient corresponding to the transmission angle α in the i-th layer of the medium i when, R(α 1 ) is the amplitude response factor of the optical fiber when the P-wave is incident at an angle α perpendicular to the optical fiber 1 angle.

[0138] As an alternative, obtaining the P-wave radiation pattern curve based on the corrected P-wave amplitude includes:

[0139] Calculate the relative relationship based on the corrected P-wave amplitude received by each geophone, and obtain the P-wave radiation pattern curve.

[0140] As an alternative, inversing the fault plane solution based on the P-wave radiation pattern curve includes:

[0141] Use the P-wave radiation pattern curve as the input, and adopt the grid search method to perform a full-space search on the spatial parameters of the fault, calculate the objective function, and thus obtain the corresponding fault plane solution.

[0142] As an alternative, the spatial parameters include the azimuth angle dip angle δ, and slip angle λ.

[0143] As an alternative, the objective function is the correlation coefficient between the P-wave radiation pattern curve and the theoretical P-wave radiation pattern curve:

[0144]

[0145] where n is the number of observation channels, that is, the number of optical fiber DAS sensing points; x i and y iare the picked and theoretical P-wave amplitude magnitudes corresponding to the i-th trace, respectively; and are the average values of the picked and theoretical P-wave amplitude magnitudes, respectively.

[0146] Example 5

[0147] The present disclosure provides an electronic device, which includes: a memory storing executable instructions; and a processor that runs the executable instructions in the memory to implement the above DAS microseismic source mechanism inversion method.

[0148] The electronic device according to an embodiment of the present disclosure includes a memory and a processor.

[0149] The memory is used to store non-transitory computer-readable instructions. Specifically, the memory may include one or more computer program products, and the computer program products may include various forms of computer-readable storage media, such as volatile memory and / or non-volatile memory. The volatile memory may include, for example, random access memory (RAM) and / or cache memory, etc. The non-volatile memory may include, for example, read-only memory (ROM), hard disk, flash memory, etc.

[0150] The processor may be a central processing unit (CPU) or other forms of processing units having data processing capabilities and / or instruction execution capabilities, and may control other components in the electronic device to perform desired functions. In an embodiment of the present disclosure, the processor is used to run the computer-readable instructions stored in the memory.

[0151] Those skilled in the art should understand that, in order to solve the technical problem of how to obtain a good user experience effect, this embodiment may also include well-known structures such as communication buses and interfaces, and these well-known structures should also be included in the protection scope of the present disclosure.

[0152] For a detailed description of this embodiment, reference may be made to the corresponding descriptions in the foregoing embodiments, and details will not be repeated here.

[0153] Example 6

[0154] The embodiment of the present disclosure provides a computer-readable storage medium, which stores a computer program, and when the computer program is executed by a processor, the DAS microseismic source mechanism inversion method described above is implemented.

[0155] The computer-readable storage medium according to an embodiment of the present disclosure stores non-transitory computer-readable instructions. When the non-transitory computer-readable instructions are run by a processor, all or part of the steps of the methods of the foregoing embodiments of the present disclosure are executed.

[0156] The above computer-readable storage media include, but are not limited to: optical storage media (e.g., CD-ROMs and DVDs), magneto-optical storage media (e.g., MOs), magnetic storage media (e.g., magnetic tapes or removable hard disks), media with built-in rewritable non-volatile memories (e.g., memory cards), and media with built-in ROMs (e.g., ROM cartridges).

[0157] Those skilled in the art should understand that the purpose of the above description of the embodiments of the present invention is only to exemplarily illustrate the beneficial effects of the embodiments of the present invention, and is not intended to limit the embodiments of the present invention to any of the examples given.

[0158] The various embodiments of the present invention have been described above. The above description is exemplary and not exhaustive, and is also not limited to the disclosed embodiments. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A DAS microseismic source mechanism inversion method, characterized in that, it includes: Pick up the P-wave amplitude, calculate the amplitude correction factor, and correct the P-wave amplitude; Obtain the P-wave radiation pattern curve according to the corrected P-wave amplitude; Invert the fault plane solution according to the P-wave radiation pattern curve.

2. The DAS microseismic source mechanism inversion method according to claim 1, wherein, Picking up the P-wave amplitude includes; Intercept the first arrival P-wave phase from the DAS microseismic monitoring record, and extract the maximum absolute amplitude value of the P-wave waveform recorded at each DAS receiving point.

3. The DAS microseismic source mechanism inversion method according to claim 1, wherein, Calculating the amplitude correction factor includes: Using the ray tracing algorithm to calculate the propagation path of the seismic wave, and calculating the propagation path length and transmission angle of the seismic wave according to the ray tracing result, and then calculating the amplitude correction factor.

4. The DAS microseismic source mechanism inversion method according to claim 3, wherein, The amplitude correction factor is: where F is the amplitude correction factor, n is the number of velocity layers, l i is the propagation path length of the seismic wave in the i-th layer of the medium, T pp (α i ) is the transmission coefficient corresponding to the transmission angle α i at the i-th layer of the medium, and R(α 1 ) is the amplitude response factor of the optical fiber when the P-wave is incident at an angle α 1 perpendicular to the optical fiber.

5. The DAS microseismic source mechanism inversion method according to claim 1, wherein, Obtaining the P-wave radiation pattern curve according to the corrected P-wave amplitude includes: Calculating the relative relationship according to the corrected P-wave amplitude received by each geophone, and obtaining the P-wave radiation pattern curve.

6. The DAS microseismic source mechanism inversion method according to claim 1, wherein, Inverting the fault plane solution according to the P-wave radiation pattern curve includes: Taking the P-wave radiation pattern curve as the input, using the grid search method to perform a full-space search on the spatial parameters of the fault, calculating the objective function, and thus obtaining the corresponding fault plane solution.

7. The DAS microseismic source mechanism inversion method according to claim 6, wherein, The objective function is the correlation coefficient between the P-wave radiation pattern curve and the theoretical P-wave radiation pattern curve: where n is the number of observation channels, i.e., the number of fiber optic DAS sensing points; x i and y i are respectively the picked and theoretical P-wave amplitude magnitudes corresponding to the i-th channel; and are respectively the average values of the picked and theoretical P-wave amplitude magnitudes.

8. A DAS microseismic source mechanism inversion device, characterized in that, it includes: A correction module that picks up the P-wave amplitude, calculates the amplitude correction factor, and corrects the P-wave amplitude; A calculation module that obtains the P-wave radiation pattern curve according to the corrected P-wave amplitude; An inversion module that inverts the fault plane solution according to the P-wave radiation pattern curve.

9. An electronic device, characterized in that, the electronic device includes: A memory that stores executable instructions; A processor that runs the executable instructions in the memory to implement the DAS microseismic source mechanism inversion method according to any one of claims 1-7.

10. A computer-readable storage medium, characterized in that, the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, it implements the DAS microseismic source mechanism inversion method according to any one of claims 1-7.

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