A microseismic source positioning method, device, equipment and medium

Abstract

The application discloses a microseismic source positioning method, device, equipment and medium, and relates to the field of earthquake monitoring, and comprises the following steps: acquiring initial seismic data, converting the initial seismic data into an envelope signal; determining a reference channel, identifying P-wave peaks and S-wave peaks on the envelope signal of the reference channel to determine a reference P-S separation point; aligning the envelope signal by using a dynamic time warping algorithm to obtain an alignment path; mapping the reference P-S separation point to each seismic channel according to the alignment path to obtain an aligned P-S separation point, and determining a wave phase travel time offset according to the alignment path; based on the aligned P-S separation point, extracting P-wave signals and S-wave signals from the envelope signal respectively to determine a P / S wave double-difference correlation function; constructing a weighted imaging operator based on the P / S wave double-difference correlation function and the wave phase travel time offset, and scanning the weighted imaging operator to determine a microseismic source position in a three-dimensional grid map. The source position can be accurately positioned under the 3D grid.

Description

Technical Field

[0001] This invention relates to the field of earthquake monitoring, and in particular to a method, device, equipment and medium for locating microseismic sources. Background Technology

[0002] In downhole microseismic monitoring, conventional correlation stacking location methods are highly susceptible to multiphase wave interference when processing signals with P-waves and S-waves arriving at similar times. Because P-waves and S-waves are not effectively separated, directly using these waveforms for correlation stacking leads to distortion of the correlation function's peak value, causing energy divergence in the source imaging and ultimately resulting in significant locational errors. Furthermore, existing advanced waveform location methods to avoid polarity reversal and multiphase interference require four-dimensional (4D) grid scanning in both space and time, resulting in extremely high computational costs. This makes them unsuitable for real-time monitoring of microseismic events in engineering operations such as fracturing, and they are highly sensitive to errors in the velocity model. The problem this invention aims to solve is: to design a method that can maintain the high computational efficiency (3D) of correlation stacking while effectively suppressing multiphase wave interference, and still achieve stable and high-precision location of microseismic sources even with low signal-to-noise ratios and errors in the velocity model.

[0003] Currently, the main existing technology is the hybrid correlation superposition method. In this method, the waveforms of the main event and the target event between adjacent detector channels are cross-correlated using double differences. Although this method improves computational efficiency, its processing flow does not explicitly separate P-wave and S-wave signals. When the P-wave and S-wave in the microseismic signal are too close, their superimposed waveforms are substituted into the correlation calculation together, causing the generated correlation function to fail to correctly align any one phase wave, resulting in blurred source imaging and location errors.

[0004] In summary, how to suppress multiphase wave interference and accurately locate it in 3D mesh is an urgent problem to be solved. Summary of the Invention

[0005] In view of this, the purpose of this invention is to provide a method, apparatus, device, and medium for locating microseismic sources, capable of suppressing multiphase wave interference and accurately locating them within a 3D grid. The specific solution is as follows: Firstly, this application provides a method for locating microseismic sources, including: Acquire initial seismic data of microseismic events in the target area, and convert the initial seismic data into envelope signals; wherein, the microseismic events include main events with known source locations and target events to be located; A reference channel is determined from the main event, and P-wave peaks and S-wave peaks are identified on the envelope signal of the reference channel. A reference PS separation point is determined based on the P-wave peaks and S-wave peaks. The envelope signal of the main event is aligned with the envelope signals of each of the target events using a dynamic time warping algorithm to obtain an alignment path. The reference PS separation point is mapped to the seismic trace of each target event according to the alignment path to obtain the aligned PS separation point, and the wave phase travel time offset is determined according to the alignment path. Based on the aligned PS separation point, P-wave signal and S-wave signal are extracted from the envelope signal of the target event, respectively. Based on the P-wave and S-wave signals, determine the P / S-wave double-difference correlation function between the main event and the target event in the target detector pair; Based on the P / S wave double-difference correlation function and the wave phase travel time offset, a weighted imaging operator is constructed. The weighted imaging operator is scanned to determine the grid points in the three-dimensional grid map of the target area that meet the preset operator value maximum condition, which are used as the microseismic source locations of the target event.

[0006] Optionally, acquiring initial seismic data of microseismic events in the target area and converting the initial seismic data into envelope signals includes: The initial seismic data of microseismic events in the target area are denoised and preprocessed to obtain denoised seismic data. The denoised seismic data is subjected to Hilbert transform to obtain the envelope signal.

[0007] Optionally, determining a reference channel from the main event, identifying P-wave peaks and S-wave peaks on the envelope signal of the reference channel, and determining a reference PS break-off point based on the P-wave peaks and S-wave peaks includes: Select a signal channel from the main event that meets a first preset condition as a reference channel; wherein, the first preset condition is the condition that satisfies the highest preset signal quality. P-wave peaks and S-wave peaks are identified on the envelope signal of the reference channel; In the envelope signal between the P-wave peak and the S-wave peak, the time point that satisfies the second preset condition is determined as the reference PS separation point; wherein, the second preset condition is the condition that satisfies the minimum preset amplitude.

[0008] Optionally, the step of aligning the envelope signal of the main event with the envelope signals of each of the target events using a dynamic time warping algorithm to obtain an alignment path includes: The envelope signal of the reference trace selected in the main event is used as the reference sequence, and the envelope signal of each seismic trace in the target event is used as the target sequence. Determine the cumulative cost matrix between the reference sequence and each of the target sequences; The cumulative cost matrix is ​​backtracked to obtain the path between the reference sequence and each of the target sequences that satisfies the preset optimal conditions, which is used as the alignment path.

[0009] Optionally, the step of extracting P-wave and S-wave signals from the envelope signal of the target event based on the aligned PS separation points includes: For the envelope signal of each target event, with the alignment PS separation point as the time boundary, a data segment of a first preset window length is intercepted along the preset time axis before the alignment PS separation point as the P-wave signal, and a data segment of a second preset window length is intercepted along the preset time axis after the alignment PS separation point as the S-wave signal.

[0010] Optionally, the step of constructing a weighted imaging operator based on the P / S wave double-difference correlation function and the wave phase travel time offset includes: Determine the theoretical double-difference travel time for each of the target detector pairs; For each of the target detector pairs, a first factor characterizing the minimization of the travel time residual is constructed by combining the peak lag time of the P / S wave double-difference correlation function, the wave phase travel time offset, and the theoretical double-difference travel time. Based on the peak amplitude of the P / S wave double-difference correlation function, a second factor characterizing the maximization of superposition energy is constructed; The first factor and the second factor are fused to obtain the weighted imaging contribution of the target detector pair; The imaging operator is generated by combining the weighted imaging contributions of each target detector pair.

[0011] Optionally, the step of scanning the weighted imaging operator to determine grid points in the three-dimensional grid map of the target area that satisfy the preset operator value maximum condition, as the location of the microseismic source of the target event, includes: Traverse each grid point in the three-dimensional grid map of the target area and determine the value of the imaging operator corresponding to each grid point; The grid points corresponding to the imaging operator that satisfy the preset maximum value condition are determined as the microseismic source locations of the target event.

[0012] Secondly, this application provides a microseismic source location device, comprising: The signal conversion module is used to acquire initial seismic data of microseismic events in the target area and convert the initial seismic data into an envelope signal; wherein, the microseismic events include main events with known source locations and target events to be located; The separation point determination module is used to determine a reference channel from the main event, identify P-wave peaks and S-wave peaks on the envelope signal of the reference channel, and determine a reference PS separation point based on the P-wave peaks and S-wave peaks. The path acquisition module is used to align the envelope signal of the main event with the envelope signals of each target event using a dynamic time warping algorithm to obtain an aligned path. The separation point alignment module is used to map the reference PS separation point to the seismic traces of each target event according to the alignment path, to obtain the aligned PS separation point, and to determine the wave phase travel time offset according to the alignment path. The signal extraction module is used to extract P-wave signals and S-wave signals from the envelope signal of the target event based on the aligned PS separation point. The function determination module is used to determine the P / S wave double-difference correlation function between the main event and the target event in the target detector pair based on the P-wave signal and the S-wave signal. The location module is used to construct a weighted imaging operator based on the P / S wave double-difference correlation function and the wave phase travel time offset, and scan the weighted imaging operator to determine the grid points in the three-dimensional grid map of the target area that meet the preset operator value maximum condition as the location of the microseismic source of the target event.

[0013] Thirdly, this application provides an electronic device, comprising: Memory, used to store computer programs; A processor is used to execute the computer program to implement the microseismic source location method as described above.

[0014] Fourthly, this application provides a computer-readable storage medium for storing a computer program; wherein, when the computer program is executed by a processor, it implements the microseismic source location method as described above.

[0015] In summary, this application first acquires initial seismic data of microseismic events in the target area and converts the initial seismic data into envelope signals. The microseismic events include main events with known source locations and target events to be located. Reference traces are determined from the main events, and P-wave and S-wave peaks are identified on the envelope signals of the reference traces. Reference PS separation points are determined based on the P-wave and S-wave peaks. Using a dynamic time warping algorithm, the envelope signals of the main events are aligned with the envelope signals of each target event to obtain an alignment path. The reference PS separation points are then mapped to the seismic traces of each target event based on the alignment path. After alignment, the PS separation point is determined, and the wave phase travel time offset is determined based on the alignment path. Based on the aligned PS separation point, P-wave and S-wave signals are extracted from the envelope signal of the target event. According to the P-wave and S-wave signals, the P / S wave double-difference correlation function between the main event and the target event in the target detector pair is determined. Based on the P / S wave double-difference correlation function and the wave phase travel time offset, a weighted imaging operator is constructed. The weighted imaging operator is scanned to determine the grid points in the three-dimensional grid map of the target area that satisfy the preset operator value maximum condition, which are used as the microseismic source locations of the target event. As can be seen from the above, this application first obtains the initial seismic data of microseismic events in the target area and converts it into an envelope signal, which includes the main event with a known source location and the target event to be located. A reference trace is determined from the main event, and the P-wave and S-wave peaks are identified on the envelope signal as reference PS separation points. Next, the envelope signals of the master event and each target event are aligned using a dynamic time warping algorithm to obtain the alignment path. Based on this, the reference separation point is mapped to the seismic trace of the target event, obtaining the aligned PS separation point and wave phase travel time offset. Then, based on the separation point, P-wave and S-wave signals are extracted from the target event envelope, and the double-difference correlation function of P / S waves between the master event and the target event in the geophone pair is calculated. Finally, a weighted imaging operator is constructed by combining the double-difference correlation function and the travel time offset. The grid point corresponding to the maximum value of the operator is scanned in the three-dimensional grid, which is the location of the microseismic source of the target event. In this way, by introducing a phase wave separation technique based on DTW (Dynamic Time Warping), the P-wave and S-wave waveforms are no longer crudely mixed for correlation calculation, thus eliminating the correlation function distortion caused by different wave phases competing for the optimal alignment time. At the same time, due to the introduction of travel time consistency weighting, the real source grid points will receive an exponentially enhanced weight, resulting in a perfect single-peak concentration of imaging energy. Furthermore, envelope features were employed for regular path searching, rendering the original waveform immune to polarity reversal and high-frequency noise. Additionally, a double-difference time-difference strategy for the main event was used, significantly reducing the systematic errors of the underground real velocity model through difference subtraction. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0017] Figure 1 This is a flowchart of a microseismic source location method disclosed in this application; Figure 2 This is a flowchart of a specific microseismic source location method disclosed in this application; Figure 3 This is a schematic diagram of the structure of a microseismic source location device disclosed in this application; Figure 4 This is a structural diagram of an electronic device disclosed in this application. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] Currently, the existing technology mainly uses the hybrid correlation superposition method, which utilizes the waveforms of the main event and the target event between adjacent detector channels to perform double-difference cross-correlation. Although this method improves computational efficiency, its processing flow does not explicitly separate P-wave and S-wave signals. When the P-wave and S-wave in the microseismic signal are too close, their superimposed waveforms are substituted into the correlation calculation together, causing the generated correlation function to fail to correctly align any one phase wave, resulting in blurred source imaging and positioning errors. To solve the above technical problems, this application discloses a microseismic source positioning method, device, equipment, and medium that can suppress multiphase wave interference and accurately locate the source in a 3D grid.

[0020] See Figure 1 As shown, this embodiment of the invention discloses a method for locating microseismic sources, including: Step S11: Obtain initial seismic data of microseismic events in the target area and convert the initial seismic data into an envelope signal; wherein, the microseismic events include main events with known source locations and target events to be located.

[0021] In this embodiment, the initial seismic data of microseismic events in the target area are preprocessed with denoising to obtain denoised seismic data. The denoised seismic data is then subjected to a Hilbert transform to obtain the envelope signal. Specifically, the initial seismic data of microseismic events acquired in the target area are first preprocessed with denoising to eliminate or suppress environmental noise, instrument noise, and interference from non-target events in the original data, thereby obtaining denoised seismic data with a relatively high signal-to-noise ratio. Subsequently, the denoised seismic data is used as input and subjected to a Hilbert transform, which converts the real signal into an analytic signal and extracts the complex modulus reflecting the signal energy envelope, ultimately obtaining an envelope signal that characterizes the change in microseismic signal amplitude over time.

[0022] Step S12: Determine a reference channel from the main event, identify P-wave peaks and S-wave peaks on the envelope signal of the reference channel, and determine the reference PS separation point based on the P-wave peaks and S-wave peaks.

[0023] In this embodiment, a signal channel satisfying a first preset condition is selected from the main event as a reference channel; wherein, the first preset condition is satisfying the condition of the highest preset signal quality; P-wave peaks and S-wave peaks are identified on the envelope signal of the reference channel; in the envelope signal between the P-wave peak and the S-wave peak, a time point satisfying a second preset condition is determined as the reference PS separation point; wherein, the second preset condition is satisfying the condition of the minimum preset amplitude. Specifically, from the multiple signal channels contained in a perforation with known coordinates or a high signal-to-noise ratio main event, the channel with the highest quality is selected as the reference channel. This means that after comparing the signal-to-noise ratio, waveform consistency, and other indicators that reflect data quality of each channel signal, the channel with the best performance is selected for subsequent analysis. Next, on the envelope signal of the reference channel, the peak positions corresponding to the P-wave and S-wave in the microseismic event, i.e., the P-wave peak and the S-wave peak, are identified respectively, thereby determining the significant energy peak points of the two waves on the time axis. Within the envelope signal range between the clearly defined P-wave peak and S-wave peak, since the transition noise between the two peaks is mainly low amplitude, the time point with the smallest envelope amplitude between the two peaks is defined as the reference PS separation point, which serves as the key dividing moment for distinguishing the energy of P-waves and S-waves.

[0024] Step S13: Using the dynamic time warping algorithm, align the envelope signal of the main event with the envelope signals of each target event to obtain the alignment path.

[0025] In this embodiment, the envelope signal of the reference trace selected in the main event is used as the reference sequence, and the envelope signal of each seismic trace in the target event is used as the target sequence. A cumulative cost matrix is ​​determined between the reference sequence and each target sequence. The cumulative cost matrix is ​​backtracked to obtain the path between the reference sequence and each target sequence that satisfies a preset optimal condition, which is then used as the alignment path. Specifically, the Dynamic Time Warping (DTW) algorithm is applied in the envelope domain to calculate the reference sequence. With target sequence Cumulative cost matrix : ; The optimal matching path, i.e. the alignment path w, is obtained by backtracking the matrix D.

[0026] Step S14: Map the reference PS separation point to the seismic traces of each target event according to the alignment path to obtain the aligned PS separation point, and determine the wave phase travel time offset according to the alignment path.

[0027] In this embodiment, using the established alignment path, the reference PS separation point is sequentially projected or mapped onto the seismic traces corresponding to each target event, thereby obtaining a corresponding aligned PS separation point in the seismic trace of each target event. Simultaneously, based on the same alignment path, by comparing the arrival times of the same wave phase on the reference trace and the seismic traces of each target event, the wave phase travel time offset can be further calculated, i.e., the quantitative deviation of each target event relative to the reference event in the propagation time of P-waves or S-waves.

[0028] Step S15: Based on the aligned PS separation point, extract the P-wave signal and S-wave signal from the envelope signal of the target event, respectively.

[0029] In this embodiment, for the envelope signal of each target event, using the aligned PS separation point as the time boundary, a data segment of a first preset window length is extracted along a preset time axis before the aligned PS separation point as the P-wave signal, and a data segment of a second preset window length is extracted along the preset time axis after the aligned PS separation point as the S-wave signal. Specifically, the aligned PS separation point of each channel... Based on this, waveforms are extracted using a fixed-length time window, for example, the P-wave window length is [missing information]. The S-wave window length is The extracted P-wave window is S-wave window is .

[0030] Step S16: Determine the P / S wave double-difference correlation function between the main event and the target event in the target detector pair based on the P-wave signal and the S-wave signal.

[0031] In this embodiment, after extracting the pure P-wave and S-wave, the P / S-wave isolation double-difference correlation function between detectors i and j in the main event and the target event is calculated respectively. : ; in, It is either a P wave or an S wave; This is the double-difference delay time.

[0032] Step S17: Based on the P / S wave double difference correlation function and the wave phase travel time offset, construct a weighted imaging operator, scan the weighted imaging operator, and determine the grid points in the three-dimensional grid map of the target area that meet the preset operator value maximum condition as the microseismic source location of the target event.

[0033] In this embodiment, the theoretical double-difference travel time of each target detector pair is determined. For each target detector pair, a first factor characterizing the minimization of travel time residuals is constructed by combining the peak lag time of the P / S wave double-difference correlation function, the wave phase travel time offset, and the theoretical double-difference travel time. Based on the peak amplitude of the P / S wave double-difference correlation function, a second factor characterizing the maximization of superposition energy is constructed. The first factor and the second factor are fused to obtain the weighted imaging contribution of the target detector pair. The imaging operator is generated by combining the weighted imaging contributions of each target detector pair. Specifically, by combining the minimization of travel time residuals and the maximization of superposition energy, a method for constructing a method for three-dimensional grid points is developed. Unified probability density weighted operator : ; in, It is a related function The lag time corresponding to the attainment of the maximum value; It is a related function The maximum amplitude; It is the theoretical double-difference travel time from the grid point to the detector pair; It is the observation travel time separation offset obtained through the DTW step; These are the standard deviations of travel time and energy, respectively.

[0034] Next, the grid points in the three-dimensional grid map of the target area are traversed to determine the value of the imaging operator corresponding to each grid point. The grid point corresponding to the imaging operator that satisfies the preset maximum value condition is determined as the location of the microseismic source of the target event. Specifically, each grid point in the pre-established three-dimensional grid map of the target area is traversed one by one. At each grid point, the specific value of the imaging operator corresponding to that grid point is calculated based on the extracted P-wave and S-wave signals and parameters such as wave phase travel time offset. After completing the scanning calculation of all grid points, the imaging operator values ​​corresponding to all grid points are compared, and the value with the largest value is selected. The location of the grid point corresponding to the maximum value is determined as the spatial location of the microseismic source in the target event.

[0035] As described above, this embodiment first acquires initial seismic data of microseismic events in the target area and converts it into envelope signals, which include main events with known source locations and target events to be located. Reference traces are determined from the main events, and the P-wave and S-wave peaks on the envelope signals are identified as reference PS separation points. Next, a dynamic time warping algorithm is used to align the envelope signals of the main events and each target event, obtaining an alignment path. Based on this, the reference separation points are mapped to the seismic traces of the target events, obtaining the aligned PS separation points and wave phase travel time offsets. Then, based on the separation points, P-wave and S-wave signals are extracted from the target event envelopes, and the P / S wave double-difference correlation function between the main event and the target event in the geophone pair is calculated. Finally, a weighted imaging operator is constructed by combining the double-difference correlation function and the travel time offset. The grid point corresponding to the maximum value of the operator is scanned in a three-dimensional grid, which is the location of the microseismic source of the target event. In this way, by introducing DTW-based phase-wave separation technology, P-wave and S-wave waveforms are no longer crudely mixed for correlation calculations, thus eliminating correlation function distortion caused by different wave phases competing for optimal alignment time. Simultaneously, due to the introduction of travel-time consistency weighting, the true source grid points receive exponentially enhanced weights, resulting in a perfect single-peak concentration of imaging energy. Furthermore, envelope features are used for regular path searching, immunizing against polarity reversal and high-frequency noise in the original waveform. Moreover, a double-difference travel-time difference strategy for the main event is employed, greatly offsetting the systematic errors of the subsurface velocity model during differential subtraction.

[0036] Based on the previous embodiment, this application discloses a method for locating microseismic sources, which can suppress multiphase wave interference and accurately locate sources in a 3D grid. Next, in scenarios such as microseismic monitoring in mining operations, for example... Figure 2 The microseismic source location method shown is explained in detail.

[0037] First, initial seismic data of microseismic events within the mining area are acquired. This data is typically obtained through continuous recordings by multiple geophones deployed in arrays on the surface or underground. It includes perforation signals or a precisely located main event, as well as target events whose source locations are yet to be determined. The raw seismic trace data of all events are then converted into envelope signals using a Hilbert transform to highlight the energy envelope shape of the wave train and suppress high-frequency oscillation noise in the original waveform.

[0038] Next, the channel with the best signal quality from the main event is selected as the reference channel, and the peaks of the P wave and S wave are identified on its envelope signal respectively. Then, the reference PS separation point between the two is determined, which is the time boundary between the energy decay of the P wave and the start of the S wave.

[0039] Subsequently, a dynamic time warping algorithm is used to align the envelope signals of the main event and each target event, resulting in an alignment path that reflects the time mapping relationship between the two. Using this alignment path, the reference PS separation point is mapped onto the seismic traces of each target event, obtaining the aligned PS separation point. At the same time, the travel time offset of the P-wave or S-wave between the main event and the target events is calculated based on the same path.

[0040] Then, using the aligned PS separation point as the boundary, data segments of a specified window length are extracted from the envelope signal of the target event, forward and backward respectively, as the P-wave and S-wave signals of that event. Subsequently, using the extracted P-wave and S-wave signals, the P / S-wave double-difference correlation function between the main event and the target event between each pair of detectors is calculated.

[0041] Finally, based on the double-difference correlation function and the previously obtained wave phase travel time offset, a weighted imaging operator is constructed, and the three-dimensional grid map of the target area is scanned point by point. The grid point with the largest imaging operator value is determined as the source location of the target microseismic event, thereby achieving high-precision source location.

[0042] See Figure 3 As shown, an embodiment of the present invention discloses a microseismic source location device, comprising: The signal conversion module 11 is used to acquire initial seismic data of microseismic events in the target area and convert the initial seismic data into an envelope signal; wherein, the microseismic events include main events with known source locations and target events to be located; The separation point determination module 12 is used to determine a reference channel from the main event, identify P-wave peaks and S-wave peaks on the envelope signal of the reference channel, and determine a reference PS separation point based on the P-wave peaks and S-wave peaks. The path acquisition module 13 is used to align the envelope signal of the main event with the envelope signals of each of the target events using a dynamic time warping algorithm to obtain an aligned path. The separation point alignment module 14 is used to map the reference PS separation point to the seismic traces of each target event according to the alignment path, to obtain the aligned PS separation point, and to determine the wave phase travel time offset according to the alignment path. Signal extraction module 15 is used to extract P-wave signal and S-wave signal respectively from the envelope signal of the target event based on the aligned PS separation point; The function determination module 16 is used to determine the P / S wave double difference correlation function between the main event and the target event in the target detector pair based on the P wave signal and the S wave signal. The location module 17 is used to construct a weighted imaging operator based on the P / S wave double difference correlation function and the wave phase travel time offset, and scan the weighted imaging operator to determine the grid point in the three-dimensional grid map of the target area that satisfies the preset operator value maximum condition as the location of the microseismic source of the target event.

[0043] As described above, this application first acquires initial seismic data of microseismic events in the target area and converts it into envelope signals, which include main events with known source locations and target events to be located. Reference traces are determined from the main events, and the P-wave and S-wave peaks on the envelope signals are identified as reference PS separation points. Next, a dynamic time warping algorithm is used to align the envelope signals of the main events and each target event, obtaining an alignment path. Based on this, the reference separation points are mapped to the seismic traces of the target events, obtaining the aligned PS separation points and wave phase travel time offsets. Then, based on the separation points, P-wave and S-wave signals are extracted from the target event envelopes, and the P / S wave double-difference correlation function between the main event and the target event in the geophone pair is calculated. Finally, a weighted imaging operator is constructed by combining the double-difference correlation function and the travel time offset. The grid point corresponding to the maximum value of the operator is scanned in a three-dimensional grid, which is the location of the microseismic source of the target event. In this way, by introducing DTW-based phase-wave separation technology, P-wave and S-wave waveforms are no longer crudely mixed for correlation calculations, thus eliminating correlation function distortion caused by different wave phases competing for optimal alignment time. Simultaneously, due to the introduction of travel-time consistency weighting, the true source grid points receive exponentially enhanced weights, resulting in a perfect single-peak concentration of imaging energy. Furthermore, envelope features are used for regular path searching, immunizing against polarity reversal and high-frequency noise in the original waveform. Moreover, a double-difference travel-time difference strategy for the main event is employed, greatly offsetting the systematic errors of the subsurface velocity model during differential subtraction.

[0044] In some specific embodiments, the signal conversion module 11 may specifically include: The data denoising unit is used to perform denoising preprocessing on the initial seismic data of microseismic events in the target area to obtain denoised seismic data; The signal acquisition unit is used to perform Hilbert transform on the denoised seismic data to obtain the envelope signal.

[0045] In some specific implementations, the separation point determination module 12 may specifically include: The reference channel selection unit is used to select a signal channel from the main event that meets a first preset condition as a reference channel; wherein, the first preset condition is to meet the condition of the highest preset signal quality. A peak identification unit is used to identify P-wave peaks and S-wave peaks on the envelope signal of the reference channel; The separation point determination unit is used to determine, in the envelope signal between the P-wave peak and the S-wave peak, a time point that satisfies a second preset condition as the reference PS separation point; wherein, the second preset condition is to satisfy the condition of minimum preset amplitude.

[0046] In some specific implementations, the path acquisition module 13 may specifically include: The sequence acquisition unit is used to take the envelope signal of the reference trace selected in the main event as the reference sequence and the envelope signal of each seismic trace in the target event as the target sequence. A matrix determination unit is used to determine the cumulative cost matrix between the reference sequence and each of the target sequences; The path acquisition unit is used to backtrack the cumulative cost matrix to obtain the path between the reference sequence and each of the target sequences that satisfies the preset optimal conditions, and use it as the alignment path.

[0047] In some specific embodiments, the signal extraction module 15 may specifically include: The signal interception unit is used to intercept the envelope signal of each of the target events, taking the aligned PS separation point as the time boundary, intercepting a data segment of a first preset window length before the aligned PS separation point along a preset time axis as the P-wave signal, and intercepting a data segment of a second preset window length after the aligned PS separation point along the preset time axis as the S-wave signal.

[0048] In some specific embodiments, the location positioning module 17 may specifically include: The time determination unit is used to determine the theoretical double-difference time of each of the target detector pairs; The first factor construction unit is used to construct a first factor characterizing the minimization of travel time residuals for each of the target detector pairs by combining the peak lag time of the P / S wave double-difference correlation function, the wave phase travel time offset, and the theoretical double-difference travel time. The second factor construction unit is used to construct a second factor characterizing the maximization of superposition energy based on the peak amplitude of the P / S wave double-difference correlation function. An imaging contribution acquisition unit is used to fuse the first factor and the second factor to obtain the weighted imaging contribution of the target detector pair. The operator generation unit is used to synthesize the weighted imaging contributions of each of the target detector pairs to generate the imaging operator.

[0049] In some specific embodiments, the location positioning module 17 may specifically include: A numerical determination unit is used to traverse each grid point in the three-dimensional grid map of the target area and determine the numerical value of the imaging operator corresponding to each grid point. The location determination unit is used to determine the grid points corresponding to the imaging operator that meet the preset maximum value condition as the microseismic source location of the target event.

[0050] Furthermore, embodiments of this application also disclose an electronic device, Figure 4 This is a structural diagram of an electronic device 20 according to an exemplary embodiment. The content of the diagram should not be construed as limiting the scope of this application. Specifically, the electronic device 20 may include: at least one processor 21, at least one memory 22, a power supply 23, a communication interface 24, an input / output interface 25, and a communication bus 26. The memory 22 stores a computer program, which is loaded and executed by the processor 21 to implement the relevant steps in the microseismic source location method disclosed in any of the foregoing embodiments. Furthermore, the electronic device 20 in this embodiment may specifically be an electronic computer.

[0051] In this embodiment, the power supply 23 is used to provide operating voltage for each hardware device on the electronic device 20; the communication interface 24 can create a data transmission channel between the electronic device 20 and external devices, and the communication protocol it follows can be any communication protocol applicable to the technical solution of this application, and is not specifically limited here; the input / output interface 25 is used to acquire external input data or output data to the outside world, and its specific interface type can be selected according to specific application needs, and is not specifically limited here.

[0052] In addition, the memory 22, as a carrier for resource storage, can be a read-only memory, random access memory, disk, or optical disk, etc. The resources stored thereon can include an operating system 221, computer programs 222, etc., and the storage method can be temporary storage or permanent storage.

[0053] The operating system 221 is used to manage and control the various hardware devices on the electronic device 20 and the computer program 222, which may be Windows Server, Netware, Unix, Linux, etc. In addition to including a computer program capable of performing a microseismic source location method executed by the electronic device 20 as disclosed in any of the foregoing embodiments, the computer program 222 may further include computer programs capable of performing other specific tasks.

[0054] Furthermore, this application also discloses a computer-readable storage medium for storing a computer program; wherein, when the computer program is executed by a processor, it implements the aforementioned microseismic source location method. Specific steps of this method can be found in the corresponding content disclosed in the foregoing embodiments, and will not be repeated here.

[0055] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to in the method section.

[0056] Those skilled in the art will further recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0057] The steps of the methods or algorithms described in conjunction with the embodiments disclosed herein can be implemented directly by hardware, a software module executed by a processor, or a combination of both. The software module can be located in random access memory (RAM), main memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the art.

[0058] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus 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 apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0059] The technical solutions provided in this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A method for locating microseismic sources, characterized in that, include: Acquire initial seismic data of microseismic events in the target area, and convert the initial seismic data into envelope signals; wherein, the microseismic events include main events with known source locations and target events to be located; A reference channel is determined from the main event, and P-wave peaks and S-wave peaks are identified on the envelope signal of the reference channel. A reference PS separation point is determined based on the P-wave peaks and S-wave peaks. The envelope signal of the main event is aligned with the envelope signals of each of the target events using a dynamic time warping algorithm to obtain an alignment path. The reference PS separation point is mapped to the seismic trace of each target event according to the alignment path to obtain the aligned PS separation point, and the wave phase travel time offset is determined according to the alignment path. Based on the aligned PS separation point, P-wave signal and S-wave signal are extracted from the envelope signal of the target event, respectively. Based on the P-wave and S-wave signals, determine the P / S-wave double-difference correlation function between the main event and the target event in the target detector pair; Based on the P / S wave double-difference correlation function and the wave phase travel time offset, a weighted imaging operator is constructed. The weighted imaging operator is scanned to determine the grid points in the three-dimensional grid map of the target area that meet the preset operator value maximum condition, which are used as the microseismic source locations of the target event.

2. The microseismic source location method according to claim 1, characterized in that, The process of acquiring initial seismic data of microseismic events in the target area and converting the initial seismic data into envelope signals includes: The initial seismic data of microseismic events in the target area are denoised and preprocessed to obtain denoised seismic data. The denoised seismic data is subjected to Hilbert transform to obtain the envelope signal.

3. The microseismic source location method according to claim 1, characterized in that, The step of determining a reference channel from the main event, identifying P-wave and S-wave peaks on the envelope signal of the reference channel, and determining a reference PS break-off point based on the P-wave and S-wave peaks includes: Select a signal channel from the main event that meets a first preset condition as a reference channel; wherein, the first preset condition is the condition that satisfies the highest preset signal quality. P-wave peaks and S-wave peaks are identified on the envelope signal of the reference channel; In the envelope signal between the P-wave peak and the S-wave peak, the time point that satisfies the second preset condition is determined as the reference PS separation point; wherein, the second preset condition is the condition that satisfies the minimum preset amplitude.

4. The microseismic source location method according to claim 1, characterized in that, The step of aligning the envelope signal of the main event with the envelope signals of each of the target events using a dynamic time warping algorithm to obtain an alignment path includes: The envelope signal of the reference trace selected in the main event is used as the reference sequence, and the envelope signal of each seismic trace in the target event is used as the target sequence. Determine the cumulative cost matrix between the reference sequence and each of the target sequences; The cumulative cost matrix is ​​backtracked to obtain the path between the reference sequence and each of the target sequences that satisfies the preset optimal conditions, which is used as the alignment path.

5. The microseismic source location method according to claim 1, characterized in that, The step of extracting P-wave and S-wave signals from the envelope signal of the target event based on the aligned PS separation points includes: For the envelope signal of each target event, with the alignment PS separation point as the time boundary, a data segment of a first preset window length is intercepted along the preset time axis before the alignment PS separation point as the P-wave signal, and a data segment of a second preset window length is intercepted along the preset time axis after the alignment PS separation point as the S-wave signal.

6. The microseismic source location method according to claim 1, characterized in that, The construction of a weighted imaging operator based on the P / S wave double-difference correlation function and the wave phase travel time offset includes: Determine the theoretical double-difference travel time for each of the target detector pairs; For each of the target detector pairs, a first factor characterizing the minimization of the travel time residual is constructed by combining the peak lag time of the P / S wave double-difference correlation function, the wave phase travel time offset, and the theoretical double-difference travel time. Based on the peak amplitude of the P / S wave double-difference correlation function, a second factor characterizing the maximization of superposition energy is constructed; The first factor and the second factor are fused to obtain the weighted imaging contribution of the target detector pair; The imaging operator is generated by combining the weighted imaging contributions of each target detector pair.

7. The microseismic source location method according to claim 1, characterized in that, The step of scanning the weighted imaging operator to determine the grid points in the three-dimensional grid map of the target area that satisfy the preset operator value maximum condition, as the location of the microseismic source of the target event, includes: Traverse each grid point in the three-dimensional grid map of the target area and determine the value of the imaging operator corresponding to each grid point; The grid points corresponding to the imaging operator that satisfy the preset maximum value condition are determined as the microseismic source locations of the target event.

8. A microseismic source location device, characterized in that, include: The signal conversion module is used to acquire initial seismic data of microseismic events in the target area and convert the initial seismic data into an envelope signal; wherein, the microseismic events include main events with known source locations and target events to be located; The separation point determination module is used to determine a reference channel from the main event, identify P-wave peaks and S-wave peaks on the envelope signal of the reference channel, and determine a reference PS separation point based on the P-wave peaks and S-wave peaks. The path acquisition module is used to align the envelope signal of the main event with the envelope signals of each target event using a dynamic time warping algorithm to obtain an aligned path. The separation point alignment module is used to map the reference PS separation point to the seismic traces of each target event according to the alignment path, to obtain the aligned PS separation point, and to determine the wave phase travel time offset according to the alignment path. The signal extraction module is used to extract P-wave signals and S-wave signals from the envelope signal of the target event based on the aligned PS separation point. The function determination module is used to determine the P / S wave double-difference correlation function between the main event and the target event in the target detector pair based on the P-wave signal and the S-wave signal. The location module is used to construct a weighted imaging operator based on the P / S wave double-difference correlation function and the wave phase travel time offset, and scan the weighted imaging operator to determine the grid points in the three-dimensional grid map of the target area that meet the preset operator value maximum condition as the location of the microseismic source of the target event.

9. An electronic device, characterized in that, include: Memory, used to store computer programs; A processor for executing the computer program to implement the microseismic source location method as described in any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, Used to store computer programs; wherein, when the computer programs are executed by a processor, they implement the microseismic source location method as described in any one of claims 1 to 7.

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