A residual moveout correction microseismic positioning method and related device

Abstract

This invention discloses a microseismic location method and related equipment with residual time difference correction. The method includes: acquiring and preprocessing continuously recorded microseismic waveform data; selecting multiple microseismic events for diffraction stacking to obtain multiple location results; calculating travel time to perform dynamic time difference correction on the event waveform records, and stacking the microseismic event gathers to obtain multiple reference gathers; calculating the residual time difference of each trace of multiple microseismic events; arithmetically averaging the multiple residual time differences to obtain the final residual time difference; using the final residual time difference to perform residual time difference correction on all continuously recorded microseismic data, and performing diffraction stacking to obtain the final location result. This invention effectively improves the detection effect and location accuracy of low signal-to-noise ratio microseismic events by using cross-correlation to calculate the residual time difference, correcting the time difference of each data trace, and then performing diffraction stacking for location, thereby enhancing the effectiveness of ground microseismic monitoring.

Description

Technical Field

[0001] This invention relates to the field of microseismic monitoring technology, and in particular to a microseismic location method, system, terminal, and computer-readable storage medium with residual time difference correction. Background Technology

[0002] Precise location of microseismic events is crucial for assessing unconventional oil and gas hydraulic fracturing. Microseismic monitoring primarily employs two observation methods: surface and in-well monitoring. Due to its greater ease of deployment and cost-effectiveness, surface microseismic monitoring is increasingly widely used. The core technology of microseismic monitoring is microseismic location. Conventional microseismic location methods mainly include travel-time inversion methods based on the arrival times of P-waves and S-waves of microseismic events, and waveform-based diffraction stacking location methods. For surface microseismic monitoring, because the location of microseismic events is relatively far from the detector, the received event energy is weak and the signal-to-noise ratio is low. Therefore, traditional arrival-time picking-based location methods are difficult to apply, and waveform-based diffraction stacking location methods are gradually becoming the mainstream.

[0003] For diffraction stacking location methods, the velocity model is one of the most important factors affecting the location results. In practical applications, the velocity model is usually a coarse one-dimensional velocity model obtained from well logging data. Then, if a perforation event occurs, its known origin location can be used to correct the velocity model. Using this velocity model for diffraction stacking location often introduces certain errors, especially for undulating surfaces or situations where there are large lateral variations in near-surface velocity. The location results may be less than ideal, leading to the fracture length and extent given by microseismic monitoring often being larger than the actual values. For surface microseismic monitoring on undulating surfaces, since it is difficult to establish accurate near-surface and underlying strata velocity models, current techniques generally first perform simple elevation correction on the original acquired data before using a one-dimensional velocity model for microseismic location. Due to static correction and velocity model errors, the detection of low signal-to-noise ratio and weak signal events is affected, resulting in high uncertainty and low accuracy in the location results, thus reducing the effectiveness of practical microseismic monitoring.

[0004] Therefore, existing technologies still need to be improved and developed. Summary of the Invention

[0005] The main objective of this invention is to provide a microseismic location method, system, terminal, and computer-readable storage medium with residual time difference correction. This invention aims to solve the problem in the prior art where simple elevation correction is performed on the original acquired data before using a one-dimensional velocity model for microseismic location. Due to static correction and velocity model errors, the detection of low signal-to-noise ratio and weak signal events is affected, resulting in high uncertainty and low accuracy in the location results, which reduces the effectiveness of actual microseismic monitoring.

[0006] To achieve the above objectives, the present invention provides a microseismic location method with residual time difference correction, the microseismic location method with residual time difference correction comprising the following steps:

[0007] Acquire the microseismic continuous recording waveform data collected by the geophones deployed for ground microseismic monitoring in the target work area, and preprocess the microseismic continuous recording waveform data;

[0008] Multiple microseismic events that meet preset requirements are selected from the preprocessed microseismic continuous recording waveform data. The source location grid parameters are determined according to the acquisition and observation system and the target area. Multiple microseismic events are then located by diffraction superposition to obtain multiple location results.

[0009] Based on the theoretically calculated travel time of each of the positioning results, the event waveform records are dynamically corrected for time difference, and the dynamically corrected microseismic event gathers are superimposed to obtain multiple reference gathers;

[0010] By performing cross-correlation calculations on each of the aforementioned reference gathers and the trace records after dynamic correction time difference, the residual time difference of each trace of multiple microseismic events is obtained;

[0011] The final residual time difference corresponding to each detector point position is obtained by arithmetically averaging the multiple residual time differences.

[0012] The remaining time difference is used to correct the remaining time difference of all continuous microseismic data, and the diffraction stacking positioning is performed on the corrected continuous microseismic data to obtain the final positioning result.

[0013] Optionally, in the microseismic location method with residual time difference correction, the preprocessing includes: bad path removal, bandpass filtering, and static elevation correction.

[0014] The bad channel removal is used to remove abnormal data recorded due to detector malfunctions or coupling problems; the bandpass filter is used to reduce noise and improve the signal-to-noise ratio of the data; the elevation static correction is used to improve the continuity of microseismic event waveforms.

[0015] Optionally, the residual time difference correction method for microseismic location, wherein determining the source location grid parameters based on the acquisition and observation system and the target area, and performing diffraction stacking on multiple microseismic events to obtain multiple location results, specifically includes:

[0016] For any microseismic event received by the detector, the theoretical timeout is expressed as:

[0017] τ i j =τ0 j +τ move j +Δτi j (1)

[0018] Where i represents the detector channel number, j represents the microseismic event number, τ0 represents the occurrence time of the microseismic event, and τ move Δτ represents the approximate travel time of seismic wave propagation in a microseismic event, and Δτ represents the remaining time difference.

[0019] If the effect of residual time difference is not considered, the location of microseismic events is calculated by diffraction stacking using the theoretical travel time calculated by the velocity model. The location imaging result is as follows:

[0020]

[0021] Where (x,y,z) represents the spatial grid location of the earthquake source, N represents the total number of records, and A i This represents the event waveform amplitude function after polarity correction of the i-th data channel;

[0022] The location of the position with the maximum energy from the localization imaging results is obtained as follows:

[0023] (x0,y0,z0)=argmax[s(x,y,z,τ0)]; (3)

[0024] Where (x0,y0,z0) represents the source coordinates determined by the microseismic event location.

[0025] Optionally, the microseismic location method with residual time difference correction, wherein the step of performing dynamic time difference correction on the event waveform record based on the theoretically calculated travel time of each location result, and superimposing the dynamically time difference-corrected microseismic event gathers to obtain multiple reference gathers, specifically includes:

[0026] Based on the location results and velocity model calculations, the theoretical travel times for each trace are obtained. After dynamic time difference correction, the arrival times of each trace for the microseismic event are expressed as follows:

[0027] t i j =τ i j -τ move j =τ0 j +Δτ i j (4)

[0028] The arrival times of the stacked gathers after time difference correction are represented as follows:

[0029]

[0030] If the remaining time difference follows a Gaussian distribution, then the second term on the right side of formula (5) tends to zero, and the arrival time of the superimposed reference gather is approximately equal to the earthquake time τ0.

[0031] Optionally, the microseismic location method with residual time difference correction, wherein the step of cross-correlation calculation using each of the reference gathers and the dynamically corrected time difference records to obtain the residual time difference of each trace of multiple microseismic events specifically includes:

[0032] The residual time difference of each channel is obtained by cross-correlation calculation using the superimposed reference gather and the dynamic correction time difference gather, and is expressed as:

[0033] Δτ i j =C[s j (t)*g j i (t)]; (6)

[0034] Where s represents the reference channel, g represents the dynamic time difference correction channel, and C[] represents the cross-correlation calculation.

[0035] Optionally, the microseismic location method with residual time difference correction, wherein the step of arithmetically averaging the multiple residual time differences to obtain the final residual time difference corresponding to each receiver location specifically includes:

[0036] The arithmetic mean of the residual time differences corresponding to all calculated microseismic events is used to obtain the final residual time difference for each trace at the corresponding receiver point, expressed as:

[0037]

[0038] Where M represents the number of selected microseismic events.

[0039] Optionally, in the residual time difference correction microseismic location method, the detector includes a single-component detector.

[0040] Furthermore, to achieve the above objectives, the present invention also provides a microseismic positioning system with residual time difference correction, wherein the microseismic positioning system with residual time difference correction includes:

[0041] The data acquisition module is used to acquire the microseismic continuous recording waveform data collected by the geophones deployed for ground microseismic monitoring in the target work area, and to preprocess the microseismic continuous recording waveform data.

[0042] The overlay positioning module is used to select multiple microseismic events that meet preset requirements from the preprocessed microseismic continuous recording waveform data, determine the source positioning grid parameters according to the acquisition and observation system and the target area, and perform diffraction overlay positioning on the multiple microseismic events to obtain multiple positioning results;

[0043] The correction and overlay module is used to perform dynamic time difference correction on the event waveform record based on the theoretically calculated travel time of each positioning result, and to overlay the dynamic time difference corrected microseismic event gathers to obtain multiple reference gathers;

[0044] The cross-correlation calculation module is used to perform cross-correlation calculations using each of the reference gathers and the trace records after dynamic correction time difference to obtain the remaining time difference of each trace of multiple microseismic events;

[0045] The arithmetic averaging module is used to perform an arithmetic average of the multiple remaining time differences to obtain the final remaining time difference corresponding to each detector point position;

[0046] The calibration and positioning module is used to perform residual time difference correction on all continuous microseismic data using the final residual time difference, and to perform diffraction stacking positioning on the continuous microseismic data after residual time difference correction to obtain the final positioning result.

[0047] Furthermore, to achieve the above objectives, the present invention also provides a terminal, wherein the terminal includes: a memory, a processor, and a residual time difference correction microseismic location program stored in the memory and executable on the processor, wherein when the residual time difference correction microseismic location program is executed by the processor, it implements the steps of the residual time difference correction microseismic location method as described above.

[0048] Furthermore, to achieve the above objectives, the present invention also provides a computer-readable storage medium, wherein the computer-readable storage medium stores a residual time difference correction microseismic location program, which, when executed by a processor, implements the steps of the residual time difference correction microseismic location method as described above.

[0049] In this invention, continuous microseismic waveform data collected by geophones deployed for ground microseismic monitoring in the target work area is acquired and preprocessed. Multiple microseismic events meeting preset requirements are selected from the preprocessed continuous microseismic waveform data. Source location grid parameters are determined based on the acquisition and observation system and the target area. Multiple microseismic events are then located using diffraction stacking to obtain multiple location results. The event waveform records are dynamically corrected for time difference based on the theoretically calculated travel time of each location result. The dynamically corrected microseismic event gathers are then stacked to obtain multiple reference gathers. Cross-correlation calculations are performed between each reference gather and each dynamically corrected gather to obtain the remaining time difference for each gather of the multiple microseismic events. The arithmetic mean of the multiple remaining time differences is used to obtain the final remaining time difference corresponding to each geophone location. The final remaining time difference is used to correct the remaining time difference of all continuous microseismic data. The continuously recorded microseismic data after remaining time difference correction is then located using diffraction stacking to obtain the final location result. This invention uses cross-correlation to calculate the remaining time difference of a small number of high signal-to-noise ratio events, then performs time difference correction on each data point before diffraction stacking for positioning. This can effectively solve the influence of static correction and velocity model errors, and can effectively improve the detection effect and positioning accuracy of low signal-to-noise ratio microseismic events, thereby enhancing the effectiveness of ground microseismic monitoring. Attached Figure Description

[0050] Figure 1 This is a flowchart of a preferred embodiment of the microseismic location method with residual time difference correction of the present invention;

[0051] Figure 2 This is a schematic diagram of a typical high signal-to-noise ratio microseismic event in a preferred embodiment of the microseismic location method with residual time difference correction of the present invention;

[0052] Figure 3 This is a schematic diagram of a microseismic event dynamic time difference correction gather in a preferred embodiment of the microseismic location method with residual time difference correction of the present invention;

[0053] Figure 4 This is a schematic diagram of a reference gather superimposed with dynamic time difference correction for microseismic location in a preferred embodiment of the residual time difference correction microseismic location method of the present invention;

[0054] Figure 5 This is a schematic diagram of the residual time difference distribution of detector points in a preferred embodiment of the microseismic location method with residual time difference correction of the present invention;

[0055] Figure 6 This is a schematic diagram of a microseismic event after residual time difference correction in a preferred embodiment of the microseismic location method with residual time difference correction of the present invention;

[0056] Figure 7This is a schematic diagram of the conventional typical event microseismic location imaging results of a preferred embodiment of the residual time difference correction microseismic location system of the present invention;

[0057] Figure 8 This is a schematic diagram of the microseismic positioning imaging results after residual time difference correction, which is a preferred embodiment of the microseismic positioning system with residual time difference correction of the present invention.

[0058] Figure 9 This is a schematic diagram of the positioning result after residual time difference correction relative to the theoretical arrival time of a preferred embodiment of the microseismic positioning system with residual time difference correction of the present invention.

[0059] Figure 10 This is a schematic diagram of the conventional microseismic migration stacking positioning results of a preferred embodiment of the microseismic positioning system with residual time difference correction of the present invention;

[0060] Figure 11 This is a schematic diagram of the microseismic migration stacking positioning result after applying residual time difference correction in a preferred embodiment of the microseismic positioning system with residual time difference correction of the present invention;

[0061] Figure 12 This is a schematic diagram of a preferred embodiment of the microseismic positioning system with residual time difference correction of the present invention;

[0062] Figure 13 This is a schematic diagram of the operating environment of a preferred embodiment of the terminal of the present invention. Detailed Implementation

[0063] To make the objectives, technical solutions, and advantages of this invention clearer and more explicit, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0064] To address the issue of low positioning accuracy caused by undulating terrain and velocity modeling in existing ground microseismic positioning technologies, this invention proposes a microseismic positioning method that uses dynamic time difference correction gathers of microseismic events for residual time difference correction. This method calculates the residual time difference using cross-correlation of a small number of high signal-to-noise ratio events, then corrects the time difference for each data source before performing diffraction stacking for positioning. This method can effectively solve the influence of static correction and velocity model errors, thereby improving the detection effect and positioning accuracy of low signal-to-noise ratio microseismic events and enhancing the effectiveness of ground microseismic monitoring.

[0065] The microseismic location method with residual time difference correction described in the preferred embodiment of the present invention, such as... Figure 1 As shown, the microseismic location method with residual time difference correction includes the following steps:

[0066] Step S100: Obtain the microseismic continuous recording waveform data collected by the detectors deployed for ground microseismic monitoring in the target work area, and preprocess the microseismic continuous recording waveform data.

[0067] The preprocessing includes: bad channel removal, bandpass filtering, and elevation static correction; bad channel removal is used to remove abnormal data recorded due to detector malfunctions or coupling problems; bandpass filtering is used to reduce noise and improve the signal-to-noise ratio of the data; and elevation static correction is used to improve the continuity of microseismic event waveforms.

[0068] Specifically, the continuous waveform data of microseismic events collected by geophones deployed for ground microseismic monitoring in the target work area is acquired. The microseismic waveform data undergoes preprocessing such as bad channel removal, bandpass filtering, and static elevation correction. Due to faults in the geophones themselves or coupling problems, some geophones record data with anomalies, requiring editing and removal. Since microseismic events typically have a certain effective frequency band, bandpass filtering can be used to improve the signal-to-noise ratio. Because the geophones deployed on the ground have different elevations, static elevation correction can be performed to improve the continuity of the microseismic event waveforms.

[0069] Step S200: Select multiple microseismic events that meet preset requirements from the preprocessed microseismic continuous recording waveform data, determine the source location grid parameters according to the acquisition and observation system and the target area, and perform diffraction superposition positioning on the multiple microseismic events to obtain multiple positioning results.

[0070] Specifically, several microseismic events with relatively high signal-to-noise ratios and relatively strong energy (preset requirements) are selected from the preprocessed data. Based on the acquisition and observation system and the target area, the source location grid parameters are determined, and the selected microseismic events are located by diffraction stacking to obtain the corresponding location results.

[0071] For any microseismic event received by the detector, its theoretical value can be approximately expressed as:

[0072] τ i j =τ0 j +τ move j +Δτ i j (1)

[0073] Where i represents the detector channel number, j represents the microseismic event number, τ0 represents the occurrence time of the microseismic event, and τ move Δτ represents the approximate travel time of seismic wave propagation in a microseismic event, and Δτ represents the remaining time difference.

[0074] If the effect of residual time difference is not considered, the location of this microseismic event can be expressed as follows: (The result of diffraction stacking based on the theoretical travel time calculated using the velocity model can be represented as follows:)

[0075]

[0076] Where (x,y,z) represents the spatial grid location of the seismic source, τ0 represents the time of occurrence of the microseismic event, N represents the total number of records, and A i This represents the amplitude function of the event waveform after polarity correction of the i-th data channel.

[0077] The location of the position with the maximum energy obtained from the above positioning imaging results can be represented as follows:

[0078] (x0,y0,z0)=argmax[s(x,y,z,τ0)]; (3)

[0079] Where (x0,y0,z0) represents the source coordinates determined by the microseismic event location.

[0080] Step S300: Perform dynamic time difference correction on the event waveform record based on the theoretically calculated travel time of each positioning result, and stack the dynamic time difference corrected microseismic event gathers to obtain multiple reference gathers.

[0081] Specifically, the event waveform records are dynamically corrected for time difference using the theoretically calculated travel times corresponding to the above-mentioned microseismic event location results, and the microseismic event gathers after dynamic time difference correction are superimposed to obtain the corresponding reference gathers.

[0082] Based on the location results and velocity model, the theoretical travel time of each trace can be calculated. Therefore, the arrival time of each trace of the microseismic event after dynamic time difference correction is expressed as follows:

[0083] t i j =τ i j -τ move j =τ0 j +Δτ i j (4)

[0084] The arrival times of the stacked gathers after time difference correction are represented as follows:

[0085]

[0086] If the remaining time difference follows a Gaussian distribution, then the second term on the right side of formula (5) tends to zero, and the arrival time of the superimposed reference gather is approximately equal to the earthquake time τ0.

[0087] Step S400: Perform cross-correlation calculations using each of the reference gathers and the trace records after dynamic time difference correction to obtain the residual time difference of each trace for multiple microseismic events, such as... Figure 5 As shown.

[0088] Specifically, the residual time difference of each channel is obtained by cross-correlation calculation using the superimposed reference gather and the dynamic correction time difference gather, which can be expressed as:

[0089] Δτ i j =C[s j (t)*g j i (t)]; (6)

[0090] Where s represents the reference channel, g represents the dynamic time difference correction channel, and C[] represents the cross-correlation calculation.

[0091] Step S500: The arithmetic mean of the multiple remaining time differences is used to obtain the final remaining time difference corresponding to each detector point position.

[0092] Specifically, the arithmetic mean of the residual time differences corresponding to all calculated microseismic events is used to obtain the final residual time difference for each trace at the corresponding receiver point, expressed as:

[0093]

[0094] Where M represents the number of selected microseismic events.

[0095] Step S600: Use the remaining time difference calculated above to perform remaining time difference correction on all continuous microseismic data, and perform diffraction stacking positioning on the corrected continuous microseismic data to obtain the positioning result.

[0096] Finally, the remaining time difference is used to correct the remaining time difference of all microseismic data, and diffraction stacking is performed on the corrected continuous microseismic data to obtain the detection and location results of microseismic events.

[0097] To further illustrate the process of the residual time difference correction microseismic location method of the present invention, an example is given below: The microseismic continuous recording waveform data is actual data acquired by surface microseismic monitoring for coalbed methane hydraulic fracturing. The acquisition and observation system adopts a near-linear grid distribution, and 758 single-component geophones are arranged on the surface near the wellhead. A one-dimensional velocity model is obtained based on the well logging data.

[0098] The microseismic continuous recording waveform data was preprocessed according to step S100. Bad trace removal was performed using inter-trace energy distribution and differences, bandpass filtering was performed using the effective frequency band of microseismic events, and static elevation correction was performed using near-surface velocity and receiver elevation distribution.

[0099] Following step S200, nine microseismic events with a signal-to-noise ratio (SNR) of 1 second in length were selected for diffraction stacking and localization. Typical high SNR microseismic events include, for example... Figure 2 As shown, the source imaging grid parameters set according to the acquisition and observation system and the target area are: X direction -500 to 1000 meters, Y direction -500 to 1000 meters, Z direction 500 to 1500 meters, and the grid interval in all three directions is 10 meters.

[0100] Following step S300, the theoretical travel time is calculated using the positioning results from step S200 to perform dynamic time difference correction on microseismic events. The corrected microseismic event gathers are as follows: Figure 3 As shown, the corrected microseismic events are basically flattened, but small disturbances (residual time difference) still exist. The reference gather is obtained by stacking the corrected gathers, as shown below. Figure 4 As shown.

[0101] Following step S400, the residual time difference of each trace is calculated by cross-correlation between the reference gather and the dynamically corrected time difference gather. The arithmetic mean of the residual time differences obtained from the nine selected high signal-to-noise ratio microseismic events is then used to obtain the final residual time difference distribution for each receiver point, as shown below. Figure 5 As shown.

[0102] Following step S600, the residual time difference obtained above is used to correct the residual time difference of the preprocessed continuous data, resulting in corrected data. Typical microseismic events after correction are shown below. Figure 6 As shown, with Figure 2 The comparison shows that the continuity of the waveform is significantly improved, indicating the rationality and accuracy of the remaining time difference calculation.

[0103] The data after remaining time difference correction is then subjected to diffraction superposition positioning again. Figure 7 These are microseismic localization imaging results for typical events. Figure 8 The results of microseismic positioning imaging after applying the residual time difference correction of this invention show that the energy is more focused. Figure 9 The theoretical arrival time (black line) calculated using the positioning results of this invention is further demonstrated. It can be seen that it matches the actual arrival time of the microseismic event waveform very well, proving the effectiveness of the method of this invention. Figure 10 This presents the microseismic event localization results obtained using conventional diffraction stacking of continuous data. Figure 11The results of microseismic event localization with residual time difference correction applied according to the present invention are shown. The comparison shows that the microseismic events are more concentrated and the spatiotemporal distribution is more reasonable.

[0104] The present invention has the following advantages:

[0105] (1) This invention improves the waveform consistency of microseismic events by using the gathers after dynamic correction of microseismic events to perform residual time difference correction, which can effectively improve the detection and location capabilities of weak events.

[0106] (2) The residual time difference correction applied by the present invention can effectively improve the positioning accuracy of microseismic events. The present invention can reduce the dependence of diffraction superposition positioning on the accuracy of velocity model and effectively improve the application effect of ground microseismic monitoring technology under complex near-surface conditions such as undulating surface.

[0107] Furthermore, such as Figure 12 As shown, based on the above-mentioned microseismic location method with residual time difference correction, the present invention also provides a microseismic location system with residual time difference correction, wherein the microseismic location system with residual time difference correction includes:

[0108] Data acquisition module 51 is used to acquire microseismic continuous recording waveform data collected by the geophones deployed for ground microseismic monitoring in the target work area, and to preprocess the microseismic continuous recording waveform data.

[0109] The superposition and positioning module 52 is used to select multiple microseismic events that meet preset requirements from the preprocessed microseismic continuous recording waveform data, determine the source positioning grid parameters according to the acquisition and observation system and the target area, and perform diffraction superposition positioning on the multiple microseismic events to obtain multiple positioning results.

[0110] The correction and overlay module 53 is used to perform dynamic time difference correction on the event waveform record based on the theoretically calculated travel time of each positioning result, and to overlay the dynamic time difference corrected microseismic event gathers to obtain multiple reference gathers;

[0111] The cross-correlation calculation module 54 is used to perform cross-correlation calculations using each of the reference gathers and the trace records after dynamic correction time difference to obtain the remaining time difference of each trace of multiple microseismic events;

[0112] Arithmetic averaging module 55 is used to perform an arithmetic average of the multiple remaining time differences to obtain the final remaining time difference corresponding to each detector point position;

[0113] The calibration and positioning module 56 is used to perform residual time difference correction on all continuous microseismic data using the final residual time difference, and to perform diffraction stacking positioning on the continuous microseismic data after residual time difference correction to obtain the final positioning result.

[0114] Furthermore, such as Figure 13 As shown, based on the microseismic location method and system with residual time difference correction described above, the present invention also provides a terminal, which includes a processor 10, a memory 20 and a display 30. Figure 13 Only some of the terminal components are shown; however, it should be understood that it is not required to implement all of the components shown, and more or fewer components may be implemented instead.

[0115] In some embodiments, the memory 20 may be an internal storage unit of the terminal, such as a hard disk or memory. In other embodiments, the memory 20 may be an external storage device of the terminal, such as a plug-in hard disk, smart media card (SMC), secure digital card (SD), flash card, etc., equipped on the terminal. Further, the memory 20 may include both internal and external storage devices. The memory 20 is used to store application software and various types of data installed on the terminal, such as the program code installed on the terminal. The memory 20 can also be used to temporarily store data that has been output or will be output. In one embodiment, the memory 20 stores a residual time difference correction (RTD) microseismic location program 40, which can be executed by the processor 10 to implement the RTD correction microseismic location method of this application.

[0116] In some embodiments, the processor 10 may be a central processing unit (CPU), a microprocessor, or other data processing chip, used to run program code stored in the memory 20 or process data, such as executing the microseismic location method with residual time difference correction.

[0117] In some embodiments, the display 30 may be an LED display, a liquid crystal display, a touch-sensitive liquid crystal display, or an OLED (Organic Light-Emitting Diode) touchscreen. The display 30 is used to display information on the terminal and to display a visual user interface. The components 10-30 of the terminal communicate with each other via a system bus.

[0118] In one embodiment, when the processor 10 executes the microseismic location program 40 for residual time difference correction in the memory 20, the following steps are performed:

[0119] Acquire the microseismic continuous recording waveform data collected by the geophones deployed for ground microseismic monitoring in the target work area, and preprocess the microseismic continuous recording waveform data;

[0120] Multiple microseismic events that meet preset requirements are selected from the preprocessed microseismic continuous recording waveform data. The source location grid parameters are determined according to the acquisition and observation system and the target area. Multiple microseismic events are then located by diffraction superposition to obtain multiple location results.

[0121] Based on the theoretically calculated travel time of each of the positioning results, the event waveform records are dynamically corrected for time difference, and the dynamically corrected microseismic event gathers are superimposed to obtain multiple reference gathers;

[0122] By performing cross-correlation calculations on each of the aforementioned reference gathers and the trace records after dynamic correction time difference, the residual time difference of each trace of multiple microseismic events is obtained;

[0123] The final residual time difference corresponding to each detector point position is obtained by arithmetically averaging the multiple residual time differences.

[0124] The remaining time difference is used to correct the remaining time difference of all continuous microseismic data, and the diffraction stacking positioning is performed on the corrected continuous microseismic data to obtain the final positioning result.

[0125] The preprocessing includes: bad sector removal, bandpass filtering, and static elevation correction;

[0126] The bad channel removal is used to remove abnormal data recorded due to detector malfunctions or coupling problems; the bandpass filter is used to reduce noise and improve the signal-to-noise ratio of the data; the elevation static correction is used to improve the continuity of microseismic event waveforms.

[0127] Specifically, the step of determining the source location grid parameters based on the acquisition and observation system and the target area, and performing diffraction stacking on multiple microseismic events to obtain multiple location results, includes:

[0128] For any microseismic event received by the detector, the theoretical timeout is expressed as:

[0129] τ i j =τ0 j +τ move j +Δτ i j (1)

[0130] Where i represents the detector channel number, j represents the microseismic event number, τ0 represents the occurrence time of the microseismic event, and τ move Δτ represents the approximate travel time of seismic wave propagation in a microseismic event, and Δτ represents the remaining time difference.

[0131] If the effect of residual time difference is not considered, the location of microseismic events is calculated by diffraction stacking using the theoretical travel time calculated by the velocity model. The location imaging result is as follows:

[0132]

[0133] Where (x,y,z) represents the spatial grid location of the earthquake source, N represents the total number of records, and A i This represents the event waveform amplitude function after polarity correction of the i-th data channel;

[0134] The location of the position with the maximum energy from the localization imaging results is obtained as follows:

[0135] (x0,y0,z0)=argmax[s(x,y,z,τ0)]; (3)

[0136] Where (x0,y0,z0) represents the source coordinates determined by the microseismic event location.

[0137] Specifically, the step of performing dynamic time difference correction on the event waveform records based on the theoretically calculated travel time of each positioning result, and then stacking the dynamically corrected microseismic event gathers to obtain multiple reference gathers, includes:

[0138] Based on the location results and velocity model calculations, the theoretical travel times for each trace are obtained. After dynamic time difference correction, the arrival times of each trace for the microseismic event are expressed as follows:

[0139] t i j =τ i j -τ move j =τ0 j +Δτ i j (4)

[0140] The arrival times of the stacked gathers after time difference correction are represented as follows:

[0141]

[0142] If the remaining time difference follows a Gaussian distribution, then the second term on the right side of formula (5) tends to zero, and the arrival time of the superimposed reference gather is approximately equal to the earthquake time τ0.

[0143] Specifically, the step of performing cross-correlation calculations between each of the reference gathers and the trace records after dynamic correction to obtain the residual time difference of each trace of multiple microseismic events includes:

[0144] The residual time difference of each channel is obtained by cross-correlation calculation using the superimposed reference gather and the dynamic correction time difference gather, and is expressed as:

[0145] Δτ i j =C[s j (t)*g j i (t)]; (6)

[0146] Where s represents the reference channel, g represents the dynamic time difference correction channel, and C[] represents the cross-correlation calculation.

[0147] Specifically, the step of arithmetically averaging the multiple remaining time differences to obtain the final remaining time difference corresponding to each receiver location includes:

[0148] The arithmetic mean of the residual time differences corresponding to all calculated microseismic events is used to obtain the final residual time difference for each trace at the corresponding receiver point, expressed as:

[0149]

[0150] Where M represents the number of selected microseismic events.

[0151] The detector includes a single-component detector.

[0152] The present invention also provides a computer-readable storage medium, wherein the computer-readable storage medium stores a residual time difference correction (RTD) microseismic location program, which, when executed by a processor, implements the steps of the RTD-corrected microseismic location method as described above.

[0153] In summary, this invention provides a microseismic location method and related equipment with residual time difference correction. The method includes: acquiring continuously recorded microseismic waveform data collected by geophones deployed for ground microseismic monitoring in the target work area; preprocessing the continuously recorded microseismic waveform data; selecting multiple microseismic events that meet preset requirements from the preprocessed continuously recorded microseismic waveform data; determining source location grid parameters based on the acquisition and observation system and the target area; performing diffraction superposition location on the multiple microseismic events to obtain multiple location results; and performing theoretical calculations based on each location result. The invention employs a method of dynamic time difference correction for event waveform records during travel. The time difference-corrected microseismic event gathers are then stacked to obtain multiple reference gathers. Cross-correlation calculations are performed between each reference gather and the time difference-corrected gathers to obtain the residual time difference for each gather of the multiple microseismic events. The arithmetic mean of these residual time differences yields the final residual time difference for each receiver location. This final residual time difference is then used to correct the residual time difference for all continuous microseismic data. Finally, diffraction stacking is performed on the corrected continuous microseismic data to obtain the final location result. This invention utilizes cross-correlation calculations for residual time differences for a small number of high signal-to-noise ratio events, followed by time difference correction for each gather before diffraction stacking for location. This effectively addresses the impact of static correction and velocity model errors, significantly improving the detection and location accuracy of low signal-to-noise ratio microseismic events and enhancing the effectiveness of ground-based microseismic monitoring.

[0154] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or terminal that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or terminal. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or terminal that includes that element.

[0155] Of course, those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware (such as a processor, controller, etc.). The program can be stored in a computer-readable storage medium, and when executed, it can include the processes described in the above method embodiments. The computer-readable storage medium can be a memory, magnetic disk, optical disk, etc.

[0156] It should be understood that the application of the present invention is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A microseismic location method with residual time difference correction, characterized in that, The microseismic location method with residual time difference correction includes: Acquire the microseismic continuous recording waveform data collected by the geophones deployed for ground microseismic monitoring in the target work area, and preprocess the microseismic continuous recording waveform data; Multiple microseismic events that meet preset requirements are selected from the preprocessed microseismic continuous recording waveform data. The source location grid parameters are determined according to the acquisition and observation system and the target area. Multiple microseismic events are then located by diffraction superposition to obtain multiple location results. Based on the theoretically calculated travel time of each of the positioning results, the event waveform records are dynamically corrected for time difference, and the dynamically corrected microseismic event gathers are superimposed to obtain multiple reference gathers; By performing cross-correlation calculations on each of the aforementioned reference gathers and the trace records after dynamic correction time difference, the residual time difference of each trace of multiple microseismic events is obtained; The final residual time difference corresponding to each detector point position is obtained by arithmetically averaging the multiple residual time differences. The remaining time difference is used to correct the remaining time difference of all continuous microseismic data, and the diffraction stacking positioning is performed on the corrected continuous microseismic data to obtain the final positioning result.

2. The microseismic location method with residual time difference correction according to claim 1, characterized in that, The preprocessing includes: bad sector removal, bandpass filtering, and static elevation correction; The bad channel removal is used to remove abnormal data recorded due to detector malfunctions or coupling problems; the bandpass filter is used to reduce noise and improve the signal-to-noise ratio of the data; and the elevation static correction is used to improve the continuity of microseismic event waveforms.

3. The microseismic location method with residual time difference correction according to claim 1, characterized in that, The process of determining the source location grid parameters based on the acquisition and observation system and the target area, and performing diffraction stacking on multiple microseismic events to obtain multiple location results specifically includes: For any microseismic event received by the detector, the theoretical timeout is expressed as: t i j =τ0 j +t move j +Δt i j (1) Where i represents the detector channel number, j represents the microseismic event number, τ0 represents the occurrence time of the microseismic event, and τ move Δτ represents the approximate travel time of seismic wave propagation in a microseismic event, and Δτ represents the remaining time difference. If the effect of residual time difference is not considered, the location of microseismic events is calculated by diffraction stacking using the theoretical travel time calculated by the velocity model. The location imaging result is as follows: Where (x,y,z) represents the spatial grid location of the earthquake source, N represents the total number of records, and A i This represents the event waveform amplitude function after polarity correction of the i-th data channel; The location of the position with the maximum energy from the localization imaging results is obtained as follows: (x0,y0,z0)=argmax[s(x,y,z,τ0)]; (3) Where (x0,y0,z0) represents the source coordinates determined by the microseismic event location.

4. The microseismic location method with residual time difference correction according to claim 3, characterized in that, The process involves performing dynamic time-difference correction on the event waveform records based on the theoretically calculated travel time of each positioning result, and then stacking the dynamically time-difference corrected microseismic event gathers to obtain multiple reference gathers. Specifically, this includes: Based on the location results and velocity model calculations, the theoretical travel times for each trace are obtained. After dynamic time difference correction, the arrival times of each trace for the microseismic event are expressed as follows: t i j =t i j -t move j =τ0 j +Δt i j (4) The arrival times of the stacked gathers after time difference correction are represented as follows: If the remaining time difference follows a Gaussian distribution, then the second term on the right side of formula (5) tends to zero, and the arrival time of the superimposed reference gather is approximately equal to the earthquake time τ0.

5. The microseismic location method with residual time difference correction according to claim 4, characterized in that, The step of cross-correlation calculation using each of the reference gathers and the trace records after dynamic correction to obtain the residual time difference of each trace of multiple microseismic events specifically includes: The residual time difference of each channel is obtained by cross-correlation calculation using the superimposed reference gather and the dynamic correction time difference gather, and is expressed as: Δτ i j =C[s j (t)*g j i (t)]; (6) Where s represents the reference channel, g represents the dynamic time difference correction channel, and C[] represents the cross-correlation calculation.

6. The microseismic location method with residual time difference correction according to claim 5, characterized in that, The step of arithmetically averaging the multiple remaining time differences to obtain the final remaining time difference corresponding to each receiver location specifically includes: The arithmetic mean of the residual time differences corresponding to all calculated microseismic events is used to obtain the final residual time difference for each trace at the corresponding receiver point, expressed as: Where M represents the number of selected microseismic events.

7. The microseismic location method with residual time difference correction according to any one of claims 1-6, characterized in that, The detector includes a single-component detector.

8. A microseismic positioning system with residual time difference correction, characterized in that, The residual time difference corrected microseismic location system includes: The data acquisition module is used to acquire the microseismic continuous recording waveform data collected by the geophones deployed for ground microseismic monitoring in the target work area, and to preprocess the microseismic continuous recording waveform data. The overlay positioning module is used to select multiple microseismic events that meet preset requirements from the preprocessed microseismic continuous recording waveform data, determine the source positioning grid parameters according to the acquisition and observation system and the target area, and perform diffraction overlay positioning on the multiple microseismic events to obtain multiple positioning results; The correction and overlay module is used to perform dynamic time difference correction on the event waveform record based on the theoretically calculated travel time of each positioning result, and to overlay the dynamic time difference corrected microseismic event gathers to obtain multiple reference gathers; The cross-correlation calculation module is used to perform cross-correlation calculations using each of the reference gathers and the trace records after dynamic correction time difference to obtain the remaining time difference of each trace of multiple microseismic events; The arithmetic averaging module is used to perform an arithmetic average of the multiple remaining time differences to obtain the final remaining time difference corresponding to each detector point position; The calibration and positioning module is used to perform residual time difference correction on all continuous microseismic data using the final residual time difference, and to perform diffraction stacking positioning on the continuous microseismic data after residual time difference correction to obtain the final positioning result.

9. A terminal, characterized in that, The terminal includes: a memory, a processor, and a residual time difference correction (RTD) microseismic location program stored in the memory and executable on the processor. When the RTD microseismic location program is executed by the processor, it implements the steps of the RTD microseismic location method as described in any one of claims 1-7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a residual time difference correction (RTD) microseismic location program, which, when executed by a processor, implements the steps of the RTD-corrected microseismic location method as described in any one of claims 1-7.

Images