Microseismic source positioning method, device, medium, equipment and positioning system

Abstract

The application discloses a microseismic source positioning method, device, medium, equipment and positioning system. The method comprises the following steps: obtaining microseismic records, P-wave travel time and S-wave travel time obtained by detecting microseismic signals of a target monitoring area by a plurality of detectors; superimposing the microseismic records by the P-wave travel time or the S-wave travel time to obtain a waveform scanning imaging profile; analyzing the P-wave travel time and the S-wave travel time to obtain P-wave first arrival time and S-wave first arrival time; obtaining a time matching scanning imaging profile by using the P-wave travel time, the S-wave travel time, the P-wave first arrival time and the S-wave first arrival time; multiplying the waveform scanning imaging profile and the time matching scanning imaging profile to obtain a final imaging profile; picking up a position point of a maximum imaging value of the final imaging profile to obtain a position of a microseismic source point of the target monitoring area. The application can improve the accuracy of microseismic source positioning.

Description

Technical Field

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

[0002] Microseismic source location is an important technology in hydraulic fracturing monitoring. By locating the rupture source, the hydraulic fracturing process, especially the fracture development morphology, can be monitored, and the monitoring results can be used to further guide hydraulic fracturing operations.

[0003] Current microseismic location methods mainly include first-arrival inversion and waveform scanning. First-arrival inversion relies on the accuracy of first-arrival picking; however, in recent years, due to increased reservoir depth and significant energy attenuation after propagation through the formation, the low signal-to-noise ratio (SNR) of seismic signals has become more prominent, making it difficult for first-arrival inversion to address this issue and resulting in low location accuracy. Waveform scanning primarily utilizes waveform information for microseismic source location, but its accuracy in locating microseismic sources along depth is not high. Summary of the Invention

[0004] The technical problem to be solved by the present invention is that the localization accuracy of microseismic sources is low in the prior art.

[0005] To address the aforementioned technical problems, this invention provides a method, apparatus, medium, equipment, and positioning system for locating microseismic sources.

[0006] A method for locating microseismic sources includes:

[0007] The microseismic records, P-wave travel times, and S-wave travel times were obtained from the microseismic signals of the target monitoring area detected by multiple geophones.

[0008] By superimposing the microseismic records with the P-wave travel time or the S-wave travel time, a waveform scanning imaging profile is obtained.

[0009] Based on the P-wave travel time and the S-wave travel time, the initial arrival times of the P-wave and the S-wave are obtained through analysis.

[0010] By utilizing the travel time of the longitudinal wave, the travel time of the transverse wave, and the time difference between the arrival time of the longitudinal wave and the arrival time of the transverse wave, a time-matched scanning imaging profile is obtained.

[0011] The final imaging profile is obtained by multiplying the waveform scanning imaging profile with the time-matched scanning imaging profile.

[0012] By picking the location point of the maximum imaging value of the final imaging profile, the location of the microseismic source point in the target monitoring area is obtained.

[0013] Optionally, the waveform scanning imaging profile includes one of a P-wave scanning imaging profile formed by P-wave scanning imaging values ​​and a shear wave scanning imaging profile formed by shear wave scanning imaging values; obtaining the waveform scanning imaging profile by superimposing the microseismic records using the P-wave travel time or the shear wave travel time includes:

[0014] or

[0015]

[0016] in, The longitudinal wave scanning imaging value of the monitoring point (x, y, z) in the target monitoring area, where M is the number of detectors, N is the number of sampling points within the time window, and C is the value of the target monitoring area. m For the microseismic record of detector m, t n The time corresponding to the nth sampling point The longitudinal wave travel time from the monitoring point (x,y,z) to the detector m; The transverse wave scan imaging value of the monitoring point (x, y, z) in the target monitoring area. The transverse wave travel time from the monitoring point (x,y,z) to the detector m.

[0017] Optionally, the step of analyzing the initial arrival times of the P-wave and the S-wave based on the P-wave travel time and the S-wave travel time includes:

[0018] The P-wave superposition value of the superposition channel is calculated based on the P-wave travel time.

[0019] The shear wave superposition value of the superposition channel is calculated based on the shear wave travel time.

[0020] The arrival times of the P-wave and the S-wave are obtained by the energy ratio method based on the P-wave superposition value and the S-wave superposition value, respectively.

[0021] Optionally, the step of calculating the P-wave stacking value of the stacking channel based on the P-wave travel time includes:

[0022]

[0023] The calculation of the shear wave superposition value of the superposition channel based on the shear wave travel time includes:

[0024]

[0025] in, The summation value of the longitudinal waves at n sampling points is given by M, where M is the number of detectors and C is the summation value of the longitudinal waves at n sampling points. m For the microseismic record of detector m, t n The time corresponding to the nth sampling point For the longitudinal wave travel time from the monitoring point (xo, yo, zo) in the target monitoring area to the detector m, The longitudinal wave travel time from the monitoring point (xo, yo, zo) in the target monitoring area to the detector r; The superposition values ​​of the shear waves at sampling points n are used for superposition. For the shear wave travel time from the monitoring point (xo, yo, zo) in the target monitoring area to the detector m, The transverse wave travel time from the monitoring point (xo, yo, zo) in the target monitoring area to the detector r;

[0026] Where (xo, yo, zo) is the center point of the target monitoring area; detector r is the detector directly above the target monitoring area.

[0027] Optionally, obtaining the first arrival times of the P-wave and the S-wave respectively using the energy ratio method based on the P-wave superposition value and the S-wave superposition value includes:

[0028] Based on the P-wave superposition value and the S-wave superposition value, multiple P-wave superposition energy ratios and multiple S-wave superposition energy ratios are calculated using the long-short time window energy ratio method.

[0029] Pick the maximum value among the P-wave superposition energy ratios, and obtain the initial arrival time of the P-wave based on the time corresponding to the maximum value among the P-wave superposition energy ratios;

[0030] Pick the maximum value among the superimposed energy ratios of the shear waves, and obtain the initial arrival time of the shear waves based on the time corresponding to the maximum value among the superimposed energy ratios of the shear waves.

[0031] Optionally, the step of calculating multiple P-wave superposition energy ratios and multiple S-wave superposition energy ratios using the long-short time window energy ratio method based on the P-wave superposition value and the S-wave superposition value respectively includes:

[0032]

[0033]

[0034] in, Let N be the P-wave superposition energy ratio at the nth sampling point. S N represents the number of sampling points in the short time window. L The number of sampling points for the long time window. This represents the superposition value of the longitudinal waves at n sampling points;

[0035] The sum of the shear wave superposition energy at the nth sampling point is given. This represents the superposition value of the transverse wave at n sampling points.

[0036] Optionally, the time-matched scanning imaging profile is an imaging profile formed by time-matched imaging values; obtaining the time-matched scanning imaging profile using the P-wave travel time, the S-wave travel time, and the time difference between the P-wave arrival time and the S-wave arrival time includes:

[0037] Based on the travel time of the longitudinal wave, the travel time of the transverse wave, the time difference between the arrival time of the longitudinal wave and the arrival time of the transverse wave, calculate the time-matched imaging values ​​of each point vertically above the center point of the target monitoring area;

[0038] Based on the time-matched imaging values ​​of each point vertically upward from the center point of the target monitoring area, the time-matched imaging values ​​of the remaining points within the target monitoring area are monitored.

[0039] Optionally, the step of calculating the time-matched imaging values ​​of each point vertically above the center point of the target monitoring area based on the travel time of the P-wave, the travel time of the S-wave, and the time difference between the arrival times of the P-wave and the S-wave includes:

[0040]

[0041] in, The time-matched imaging values ​​of the monitoring points (xo, yo, z) in the target monitoring area are used. The initial arrival time of the longitudinal wave is... The initial arrival time of the transverse wave is... For the longitudinal wave traveling from (xo, yo, z) to detector r, For the transverse wave travel time from (xo, yo, z) to detector r;

[0042] Where (xo, yo, z) is the point vertically above the center point of the target monitoring area, and detector r is the detector directly above the target monitoring area.

[0043] Optionally, monitoring the time-matched imaging values ​​of other points within the target monitoring area based on the time-matched imaging values ​​of each point vertically above the center point of the target monitoring area includes:

[0044]

[0045] Where, x min Let x represent the minimum value of x. max Represents the maximum value of x, y min Let y represent the minimum value of y. max This represents the maximum value of y.

[0046] A microseismic source location device, comprising:

[0047] The information acquisition module is used to acquire microseismic records, P-wave travel times, and S-wave travel times obtained from the microseismic signals detected by multiple detectors in the target monitoring area.

[0048] The first imaging module is used to superimpose the microseismic record by the P-wave travel time or the S-wave travel time to obtain a waveform scanning imaging profile.

[0049] The time analysis module is used to analyze and obtain the initial arrival time of the P-wave and the initial arrival time of the S-wave based on the P-wave travel time and the S-wave travel time.

[0050] The second imaging module is used to obtain a time-matched scanning imaging profile by utilizing the travel time of the longitudinal wave, the travel time of the transverse wave, and the time difference between the arrival time of the longitudinal wave and the arrival time of the transverse wave.

[0051] The imaging processing module is used to multiply the waveform scanning imaging profile with the time-matched scanning imaging profile to obtain the final imaging profile;

[0052] The seismic source location module is used to pick up the location point of the maximum imaging value of the final imaging profile, and obtain the location of the microseismic source point in the target monitoring area.

[0053] A computer-readable storage medium having a computer program stored thereon, the computer program performing the following steps when executed by a processor:

[0054] The microseismic records, P-wave travel times, and S-wave travel times were obtained from the microseismic signals of the target monitoring area detected by multiple geophones.

[0055] By superimposing the microseismic records with the P-wave travel time or the S-wave travel time, a waveform scanning imaging profile is obtained.

[0056] Based on the P-wave travel time and the S-wave travel time, the initial arrival times of the P-wave and the S-wave are obtained through analysis.

[0057] By utilizing the travel time of the longitudinal wave, the travel time of the transverse wave, and the time difference between the arrival time of the longitudinal wave and the arrival time of the transverse wave, a time-matched scanning imaging profile is obtained.

[0058] The final imaging profile is obtained by multiplying the waveform scanning imaging profile with the time-matched scanning imaging profile.

[0059] By picking the location point of the maximum imaging value of the final imaging profile, the location of the microseismic source point in the target monitoring area is obtained.

[0060] A positioning device includes a memory and a processor, the memory storing a computer program, and the processor executing the computer program to perform the following steps:

[0061] The microseismic records, P-wave travel times, and S-wave travel times were obtained from the microseismic signals of the target monitoring area detected by multiple geophones.

[0062] By superimposing the microseismic records with the P-wave travel time or the S-wave travel time, a waveform scanning imaging profile is obtained.

[0063] Based on the P-wave travel time and the S-wave travel time, the initial arrival times of the P-wave and the S-wave are obtained through analysis.

[0064] By utilizing the travel time of the longitudinal wave, the travel time of the transverse wave, and the time difference between the arrival time of the longitudinal wave and the arrival time of the transverse wave, a time-matched scanning imaging profile is obtained.

[0065] The final imaging profile is obtained by multiplying the waveform scanning imaging profile with the time-matched scanning imaging profile.

[0066] By picking the location point of the maximum imaging value of the final imaging profile, the location of the microseismic source point in the target monitoring area is obtained.

[0067] A positioning system includes a detector and the aforementioned positioning device, wherein the detector is connected to the positioning device.

[0068] By superimposing microseismic records based on P-wave or S-wave travel times to obtain waveform scanning imaging profiles, the imaging effect of microseismic signals can be improved. This method has low requirements for the signal-to-noise ratio of microseismic signals. By obtaining time scanning imaging profiles based on the time difference between the first arrival times of P-waves and S-waves, as well as the travel times of P-waves and S-waves, the information of P-waves and S-waves can be fully utilized, which can improve the positioning accuracy of microseismic sources in the depth direction. Therefore, the overall positioning accuracy of microseismic sources can be improved. Attached Figure Description

[0069] The scope of this disclosure can be better understood by reading the following detailed description of exemplary embodiments in conjunction with the accompanying drawings. The accompanying drawings are:

[0070] Figure 1 This is a flowchart illustrating a microseismic source location method in one embodiment;

[0071] Figure 2 This is a structural block diagram of a microseismic source location device in one embodiment;

[0072] Figure 3 The image shows a medium-intensity surface shallow well microseismic signal from Example 1.

[0073] Figure 4 This is a cross-sectional view of longitudinal wave scanning imaging in Application Example 1;

[0074] Figure 5 This is a cross-sectional view of shear wave scanning imaging in Application Example 1;

[0075] Figure 6 This is a cross-sectional view of time-matched scanning imaging in Application Example 1;

[0076] Figure 7 To obtain the final imaging profile under P-wave and S-wave constraints by multiplying the P-wave scanning imaging profile and the time-matched scanning imaging profile in Example 1.

[0077] Figure 8 To obtain the final imaging profile under P-wave and S-wave constraints by multiplying the transverse wave scanning imaging profile from Example 1 and the time-matched scanning imaging profile.

[0078] Figure 9 The microseismic signal diagram of a shallow well with weak ground in Example 2;

[0079] Figure 10 This is a longitudinal wave scanning imaging profile from Example 2.

[0080] Figure 11 This is a cross-sectional view of the shear wave scanning imaging in Application Example 2;

[0081] Figure 12 This is a cross-sectional view of time-matched scanning imaging in Example 2.

[0082] Figure 13 To obtain the final imaging profile under P-wave and S-wave constraints by multiplying the P-wave scanning imaging profile and the time-matched scanning imaging profile in Example 2.

[0083] Figure 14 The final imaging profile under longitudinal and transverse wave constraints is obtained by multiplying the transverse wave scanning imaging profile in Example 2 with the time-matched scanning imaging profile. Detailed Implementation

[0084] To make the objectives, technical solutions, and advantages of the present invention clearer, the implementation method of the present invention will be described in detail below with reference to the accompanying drawings and embodiments, so that the process of how the present invention uses technical means to solve technical problems and achieve technical effects can be fully understood and implemented accordingly.

[0085] Microseismic source location methods originate from natural earthquake location methods, the earliest being the classic Gieger method (1912), which picks up the first arrival of seismic signals and then locates the earthquake source through an inversion iterative method based on constructing an objective function. Subsequently, Douglas (1967) proposed the Joint Epicenter Determination (JED) method, which reduces the impact of velocity model errors on source location through multi-event localization. Later, domestic and international experts and scholars (Dewey, 1972; Wang Chunyong et al., 1993; Spence, 1980; Zhou Shiyong et al., 1999) improved upon the JED method, forming relative location algorithms. All of the above methods can be classified as first-arrival inversion location methods, which depend on the accuracy of the first arrival picking of seismic waves.

[0086] In recent years, due to the increased depth of fractured reservoirs, the energy of seismic sources has attenuated significantly after propagating through the strata, resulting in a more prominent problem of low signal-to-noise ratio in seismic signals. Wang Weibao et al. (2012) proposed a ground microseismic emission tomography (SET) localization algorithm, which uses travel time information to perform migration and multichannel correlation processing on ground microseismic signals, reducing the impact of noise on microseismic localization. Gajewski et al. (2005, 2007) located microseismic sources by performing reverse-time backward extension wavefield on microseismic records. Saenger (2010) performed reverse-time localization of microseismic events using the acoustic wave equation. Sava (2008, 2011) reduced the crosstalk problem in the reverse-time backward extension wavefield by using interferometric imaging conditions. Wang Chenlong et al. (2013) and Li Zhenchun et al. (2014) conducted a joint ground-rail reverse-time localization study of microseismic events. The above method can be classified as a waveform scanning method, which mainly uses waveform information to locate microseismic sources. However, it is difficult to combine P-wave and S-wave information during the location process, resulting in low accuracy in locating the depth direction of microseismic sources.

[0087] In summary, current microseismic location methods mainly include first-arrival inversion and waveform scanning. First-arrival inversion methods are less able to address the poor signal-to-noise ratio of seismic signals, while waveform scanning methods cannot fully utilize P-wave and S-wave information. Both methods are difficult to accurately locate weak microseismic signals in three dimensions.

[0088] Based on this, the present invention provides a solution that can improve the accuracy of microseismic source location.

[0089] Example 1

[0090] like Figure 1 As shown, a method for locating microseismic sources is provided, including the following steps:

[0091] S110: Obtain microseismic records, P-wave travel times, and S-wave travel times from microseismic signals detected by multiple geophones in the target monitoring area.

[0092] The target monitoring area is the region where microseismic sources need to be detected. It can be located in shallow wells and may include multiple monitoring points; that is, the target monitoring area can be the area of ​​shallow wells. Geophones are placed on the ground above the shallow wells. The P-wave travel time refers to the P-wave travel time from the source point to the geophone, and the S-wave travel time refers to the S-wave travel time from the source point to the geophone.

[0093] S120: Microseismic records are superimposed using either P-wave or S-wave travel time to obtain waveform scanning imaging profiles.

[0094] Specifically, waveform scanning imaging profiles can be obtained by superimposing microseismic records during P-wave travel or by superimposing microseismic records during S-wave travel.

[0095] S130: Based on the travel time of the P-wave and the travel time of the S-wave, the arrival times of the P-wave and the S-wave are obtained through analysis.

[0096] S140: Time-matched scanning imaging profiles are obtained by utilizing the travel time of the P-wave, the travel time of the S-wave, and the time difference between the arrival times of the P-wave and the S-wave.

[0097] The time difference between the arrival times of the longitudinal wave and the transverse wave is the difference between the arrival times of the longitudinal wave and the transverse wave, for example, the value of the arrival time of the longitudinal wave minus the arrival time of the transverse wave.

[0098] S150: Multiply the waveform scanning imaging profile with the time-matched scanning imaging profile to obtain the final imaging profile.

[0099] Multiplying the waveform scanning imaging profile with the time-matched scanning imaging profile can be done by multiplying the imaging values ​​of each position point of the waveform scanning imaging profile with the imaging values ​​of the corresponding position points of the time-matched scanning imaging profile to obtain the imaging values ​​of each position point of the final imaging profile.

[0100] S160: Pick the location of the maximum imaging value of the final imaging profile to obtain the location of the microseismic source point in the target monitoring area.

[0101] The aforementioned microseismic source location method obtains waveform scanning imaging profiles by superimposing microseismic records based on P-wave travel time or S-wave travel time, thereby improving the imaging effect of microseismic signals. It has low requirements for the signal-to-noise ratio of microseismic signals. By obtaining time scanning imaging profiles based on the time difference between the first arrival times of P-waves and S-waves, as well as the P-wave and S-wave travel times, it makes full use of P-wave and S-wave information, which can improve the positioning accuracy in the depth direction of microseismic sources. Therefore, it can improve the overall positioning accuracy of microseismic sources.

[0102] The above-mentioned microseismic source location method can still achieve accurate three-dimensional location of microseismic sources under weak microseismic signal conditions. Compared with the first arrival inversion location method, it has lower requirements for the signal-to-noise ratio of microseismic signals. Compared with the waveform scanning method, it makes full use of P-wave and S-wave information and improves the location accuracy of microseismic sources in the depth direction.

[0103] Optionally, the waveform scanning imaging profile includes one of a P-wave scanning imaging profile formed by P-wave scanning imaging values ​​and a shear wave scanning imaging profile formed by shear wave scanning imaging values. Specifically, the P-wave scanning imaging profile is a waveform scanning imaging profile obtained by stacking microseismic records during P-wave travel; the shear wave scanning imaging profile is a waveform scanning imaging profile obtained by stacking microseismic records during shear wave travel.

[0104] Step S120 includes:

[0105] or

[0106]

[0107] in, The P-wave scanning imaging values ​​at monitoring points (x, y, z) within the target monitoring area, where M is the number of detectors, N is the number of sampling points within the time window, and C... m For the microseismic record of detector m, t n The time corresponding to the nth sampling point The longitudinal wave travel time from the monitoring point (x,y,z) to the detector m; The transverse wave scan imaging values ​​of the monitoring point (x, y, z) in the target monitoring area. The transverse wave travel time from the monitoring point (x,y,z) to the detector m.

[0108] By stacking the microseismic records using P-wave travel time, P-wave scanning imaging values ​​at each point are obtained, and a P-wave scanning imaging profile is formed by scanning all points in the monitoring area. Similarly, by stacking the microseismic records using S-wave travel time, S-wave scanning imaging values ​​at each point are obtained, and a S-wave scanning imaging profile is formed by scanning all points in the monitoring area.

[0109] Optionally, step S130 includes steps (a1) to (a3).

[0110] Step (a1): Calculate the P-wave stacking value of the stacking channel based on the P-wave travel time.

[0111] Specifically, the microseismic records are corrected using P-wave travel time to form a stacking trace.

[0112] Step (a2): Calculate the shear wave superposition value of the superposition channel based on the shear wave travel time.

[0113] Specifically, shear wave travel time is used to correct microseismic records to form stack traces.

[0114] Step (a3): Based on the superposition values ​​of the P-wave and the S-wave, the arrival times of the P-wave and the S-wave are obtained by the energy ratio method.

[0115] Specifically, the arrival time of the P-wave is obtained by the energy ratio method based on the P-wave superposition value; the arrival time of the S-wave is obtained by the energy ratio method based on the S-wave superposition value.

[0116] Optionally, step (a1) includes:

[0117]

[0118] Step (a2) includes:

[0119]

[0120] in, The summation value of the longitudinal waves at n sampling points is given by M, where M is the number of detectors and C is the summation value of the longitudinal waves at n sampling points. m For the microseismic record of detector m, t n The time corresponding to the nth sampling point When the longitudinal wave travels from the monitoring point (xo, yo, zo) in the target monitoring area to the detector m, The longitudinal wave travel time from the monitoring point (xo, yo, zo) in the target monitoring area to the detector r; The superposition values ​​of the shear waves at sampling points n are used for superposition. When the transverse wave travels from the monitoring point (xo, yo, zo) in the target monitoring area to the detector m, The transverse wave travel time from the monitoring point (xo, yo, zo) in the target monitoring area to the detector r. Here, (xo, yo, zo) is the center point of the target monitoring area; detector r is the detector directly above the target monitoring area. Specifically, "directly above" means above the center point.

[0121] Optionally, step (a3) ​​includes steps (a31) to (a33).

[0122] Step (a31): Based on the P-wave superposition value and the S-wave superposition value, calculate multiple P-wave superposition energy ratios and multiple S-wave superposition energy ratios using the long-short time window energy ratio method.

[0123] Specifically, based on the P-wave superposition values, multiple P-wave superposition energy ratios are calculated using the long-short time window energy ratio method; based on the S-wave superposition values, multiple S-wave superposition energy ratios are calculated using the long-short time window energy ratio method.

[0124] Step (a32): Pick the maximum value in the P-wave superposition energy ratio, and obtain the initial arrival time of the P-wave based on the time corresponding to the maximum value in the P-wave superposition energy ratio.

[0125] For example, the moment of initial arrival of the longitudinal wave. = Record the initial time + the maximum value of the P-wave superposition energy ratio nP * sampling interval.

[0126] Step (a33): Pick the maximum value in the superposition energy ratio of the transverse waves, and obtain the initial arrival time of the transverse waves based on the time corresponding to the maximum value in the superposition energy ratio of the transverse waves.

[0127] For example, the initial arrival time of the shear wave = the initial recording time + the maximum value of the shear wave superposition energy ratio * sampling interval.

[0128] In practical applications, the corresponding long and short time window energy ratio curves can be obtained through the long and short time window energy ratio method. The first arrival times of the P-wave and S-wave can be obtained by picking the maximum value time in the corresponding long and short time window energy ratio curves.

[0129] Optionally, step (a31) includes:

[0130]

[0131]

[0132] in, Let N be the P-wave superposition energy ratio at the nth sampling point. S N represents the number of sampling points in the short time window. L The number of sampling points for the long time window. This represents the superposition value of the longitudinal waves at n sampling points; The sum of the shear wave superposition energy at the nth sampling point is given. This represents the superposition value of the transverse wave at n sampling points.

[0133] Optionally, the time-matched scanning imaging profile is an imaging profile formed by time-matched imaging values. Step S140 includes steps (b1) to (b2).

[0134] Step (b1): Calculate the time-matched imaging values ​​of each point vertically above the center point of the target monitoring area based on the travel time of the P-wave, the travel time of the S-wave, the time difference between the arrival times of the P-wave and the S-wave.

[0135] Step (b2): Based on the time-matched imaging values ​​of each point vertically above the center point of the target monitoring area, monitor the time-matched imaging values ​​of the remaining points within the target monitoring area.

[0136] Further, step (b1) includes:

[0137]

[0138] in, For the time-matched imaging values ​​of the monitoring points (xo, yo, z) in the target monitoring area, The moment of initial arrival of the longitudinal wave, The moment of initial arrival of the transverse wave. For the longitudinal wave traveling from (xo, yo, z) to detector r, Let (xo, yo, z) be the transverse wave travel time from detector r to detector r; where (xo, yo, z) is the point vertically above the center point of the target monitoring area, and detector r is the detector directly above the target monitoring area.

[0139] Further, step (b2) includes:

[0140]

[0141] Where, x min Let x represent the minimum value of x. max Represents the maximum value of x, y min Let y represent the minimum value of y. max This represents the maximum value of y; The time-matched imaging values ​​of the monitoring points (x, y, z) in the target monitoring area.

[0142] Optionally, taking the waveform scanning imaging profile as the longitudinal wave scanning imaging profile as an example, the imaging formula for the final imaging profile in step S150 is as follows:

[0143]

[0144] Among them, S x,y,z The image value of the final imaging profile of the monitoring point (x,y,z).

[0145] It is understandable that if the waveform scanning imaging profile is a shear wave scanning imaging profile, then the imaging formula for the final imaging profile is as follows:

[0146]

[0147] Optionally, step S160 includes: selecting the imaging value of the final imaging profile of a point within the target monitoring area as the starting point, and recording the position of the selected point; sequentially comparing the imaging values ​​of other points within the target monitoring area with the imaging value of the starting point; if the imaging value of the starting point is smaller, then selecting a point with an imaging value greater than the starting point as the new starting point, and updating the imaging value and position of the starting point; if the imaging value of the starting point is larger, then comparing the next point. This process continues until all points have been compared, and the maximum value among the imaging values ​​of the final imaging profile is selected, with the location of the maximum value being the location of the microseismic source point.

[0148] It should be understood that, although Figure 1 The steps in the flowchart are shown sequentially as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order in which these steps are executed, and they can be performed in other orders. Figure 1 At least some of the steps in the process may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but may be executed at different times. The execution order of these steps or stages is not necessarily sequential, but may be executed in turn or alternately with other steps or at least some of the steps or stages in other steps.

[0149] Example 2

[0150] like Figure 2 As shown, a microseismic source location device is provided, including an information acquisition module 210, a first imaging module 220, a time analysis module 230, a second imaging module 240, an imaging processing module 250, and a source location module 260.

[0151] The information acquisition module 210 is used to acquire microseismic records, P-wave travel times, and S-wave travel times obtained from the microseismic signals of the target monitoring area detected by multiple detectors.

[0152] The first imaging module 220 is used to superimpose the microseismic record by means of the P-wave travel time or the S-wave travel time to obtain a waveform scanning imaging profile.

[0153] The time analysis module 230 is used to analyze and obtain the initial arrival time of the P-wave and the initial arrival time of the S-wave based on the P-wave travel time and the S-wave travel time.

[0154] The second imaging module 240 is used to obtain a time-matched scanning imaging profile by utilizing the travel time of the longitudinal wave, the travel time of the transverse wave, and the time difference between the arrival time of the longitudinal wave and the arrival time of the transverse wave.

[0155] The imaging processing module 250 is used to multiply the waveform scanning imaging profile with the time-matched scanning imaging profile to obtain the final imaging profile.

[0156] The seismic source location module 260 is used to pick up the location point of the maximum imaging value of the final imaging profile, and obtain the location of the microseismic source point of the target monitoring area.

[0157] The aforementioned microseismic source location device obtains waveform scanning imaging profiles by superimposing microseismic records based on P-wave travel time or S-wave travel time, thereby improving the imaging effect of microseismic signals. It has low requirements for the signal-to-noise ratio of microseismic signals. By obtaining time scanning imaging profiles based on the time difference between the first arrival times of P-waves and S-waves, as well as the P-wave and S-wave travel times, it makes full use of P-wave and S-wave information, which can improve the positioning accuracy in the depth direction of microseismic sources. Therefore, it can improve the overall positioning accuracy of microseismic sources.

[0158] Optionally, the waveform scanning imaging profile includes one of a P-wave scanning imaging profile formed by P-wave scanning imaging values ​​and a shear wave scanning imaging profile formed by shear wave scanning imaging values. Specifically, the P-wave scanning imaging profile is a waveform scanning imaging profile obtained by stacking microseismic records during P-wave travel; the shear wave scanning imaging profile is a waveform scanning imaging profile obtained by stacking microseismic records during shear wave travel.

[0159] The first imaging module 220 obtains the longitudinal wave scanning imaging value according to the following formula:

[0160]

[0161] Alternatively, the transverse wave scanning imaging values ​​can be obtained using the following formula:

[0162]

[0163] in, The P-wave scanning imaging values ​​at monitoring points (x, y, z) within the target monitoring area, where M is the number of detectors, N is the number of sampling points within the time window, and C... m For the microseismic record of detector m, t n The time corresponding to the nth sampling point The longitudinal wave travel time from the monitoring point (x,y,z) to the detector m; The transverse wave scan imaging values ​​of the monitoring point (x, y, z) in the target monitoring area. The transverse wave travel time from the monitoring point (x,y,z) to the detector m.

[0164] Optionally, the time analysis module 230 is used to calculate the P-wave superposition value of the superposition channel based on the P-wave travel time; calculate the S-wave superposition value of the superposition channel based on the S-wave travel time; and obtain the P-wave first arrival time and the S-wave first arrival time respectively by means of the energy ratio method based on the P-wave superposition value and the S-wave superposition value.

[0165] Optionally, the time analysis module 230 calculates the P-wave superposition value of the superposition channel according to the following formula:

[0166]

[0167] The timing analysis module 230 calculates the shear wave superposition value of the superposition channel according to the following formula:

[0168]

[0169] in, The summation value of the longitudinal waves at n sampling points is given by M, where M is the number of detectors and C is the summation value of the longitudinal waves at n sampling points. m For the microseismic record of detector m, t n The time corresponding to the nth sampling point When the longitudinal wave travels from the monitoring point (xo, yo, zo) in the target monitoring area to the detector m, The longitudinal wave travel time from the monitoring point (xo, yo, zo) in the target monitoring area to the detector r; The superposition values ​​of the shear waves at sampling points n are used for superposition. When the transverse wave travels from the monitoring point (xo, yo, zo) in the target monitoring area to the detector m, The transverse wave travel time from the monitoring point (xo, yo, zo) in the target monitoring area to the detector r;

[0170] Where (xo, yo, zo) is the center point of the target monitoring area; detector r is the detector directly above the target monitoring area.

[0171] Optionally, the time analysis module 230 obtains the arrival times of the P-wave and the S-wave respectively using the energy ratio method based on the P-wave superposition value and the S-wave superposition value, including: calculating multiple P-wave superposition energy ratios and multiple S-wave superposition energy ratios using the long-short time window energy ratio method based on the P-wave superposition value and the S-wave superposition value respectively; picking the maximum value among the P-wave superposition energy ratios, and obtaining the arrival time of the P-wave based on the time corresponding to the maximum value among the P-wave superposition energy ratios; picking the maximum value among the S-wave superposition energy ratios, and obtaining the arrival time of the S-wave based on the time corresponding to the maximum value among the S-wave superposition energy ratios.

[0172] Optionally, the time analysis module 230 calculates the P-wave superposition energy ratio and the S-wave superposition energy ratio according to the following formula:

[0173]

[0174]

[0175] in, Let N be the P-wave superposition energy ratio at the nth sampling point. S N represents the number of sampling points in the short time window. L The number of sampling points for the long time window. This represents the superposition value of the longitudinal waves at n sampling points; The sum of the shear wave superposition energy at the nth sampling point is given. This represents the superposition value of the transverse wave at n sampling points.

[0176] Optionally, the time-matched scanning imaging profile is an imaging profile formed by time-matched imaging values. The second imaging module 240 is used to: calculate the time-matched imaging values ​​of each point in the vertical direction of the center point of the target monitoring area based on the P-wave travel time, the S-wave travel time, and the time difference between the P-wave arrival time and the S-wave arrival time; and monitor the time-matched imaging values ​​of the remaining points in the target monitoring area based on the time-matched imaging values ​​of each point in the vertical direction of the center point of the target monitoring area.

[0177] Furthermore, the second imaging module 240 calculates the time-matched imaging values ​​of each point vertically above the center point of the target monitoring area according to the following formula:

[0178]

[0179] in, For the time-matched imaging values ​​of the monitoring points (xo, yo, z) in the target monitoring area, The moment of initial arrival of the longitudinal wave, The moment of initial arrival of the transverse wave. For the longitudinal wave traveling from (xo, yo, z) to detector r, Let (xo, yo, z) be the transverse wave travel time from detector r to detector r; where (xo, yo, z) is the point vertically above the center point of the target monitoring area, and detector r is the detector directly above the target monitoring area.

[0180] Furthermore, the second imaging module 240 obtains the time-matched imaging values ​​of the remaining points within the target monitoring area according to the following formula:

[0181]

[0182] Where, x min Let x represent the minimum value of x. max Represents the maximum value of x, y min Let y represent the minimum value of y. max This represents the maximum value of y; The time-matched imaging values ​​of the monitoring points (x, y, z) in the target monitoring area.

[0183] Optionally, taking the waveform scanning imaging profile as the longitudinal wave scanning imaging profile as an example, the imaging formula for the final imaging profile is as follows:

[0184]

[0185] Among them, S x,y,z The image value of the final imaging profile of the monitoring point (x,y,z).

[0186] It is understandable that if the waveform scanning imaging profile is a shear wave scanning imaging profile, then the imaging formula for the final imaging profile is as follows:

[0187]

[0188] Optionally, the seismic source location module 260 selects the imaging value of the final imaging profile of a point within the target monitoring area as the starting point and records the location of the selected point. It then sequentially compares the imaging values ​​of other points within the target monitoring area with the imaging value of the starting point. If the imaging value of the starting point is smaller, a point with a larger imaging value is selected as the new starting point, and the imaging value and location of the starting point are updated. If the imaging value of the starting point is larger, the next point is compared. This process continues until all points have been compared, and the maximum value in the final imaging profile is selected. The location of this maximum value is the location of the microseismic source point.

[0189] Specific limitations regarding the microseismic source location device can be found in the limitations of the microseismic source location method described above, and will not be repeated here. Each module in the aforementioned microseismic source location device can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in hardware or independently of the processor in the location device, or stored in software in the memory of the location device, so that the processor can call and execute the operations corresponding to each module. It should be noted that the module division in this embodiment is illustrative and only represents a logical functional division; other division methods may be used in actual implementation.

[0190] Example 3

[0191] A computer-readable storage medium is provided on which a computer program is stored, which, when executed by a processor, implements the steps of the methods in the above embodiments.

[0192] The aforementioned computer-readable storage medium, by storing a computer program capable of implementing the methods of the above embodiments, can similarly improve the accuracy of microseismic source location.

[0193] Example 4

[0194] A positioning device is provided, including a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the steps of the methods in the above embodiments.

[0195] The positioning device described above, by implementing the steps of the methods in the above embodiments, similarly achieves high accuracy in locating microseismic sources.

[0196] Example 5

[0197] A positioning system is provided, including a detector and the positioning device in the above embodiments, wherein the detector is connected to the positioning device.

[0198] The aforementioned positioning system, due to the use of the aforementioned positioning equipment, similarly achieves high accuracy in locating microseismic sources.

[0199] To better illustrate the effects of the present invention, the following description is provided in conjunction with practical application examples:

[0200] Application Example 1

[0201] The microseismic source location method of this invention is applied to perform scanning and location of medium-intensity surface shallow well microseismic signals, such as... Figure 3 The image shows a medium-intensity surface shallow well microseismic signal. Figure 4 The image shows a longitudinal wave scanning imaging profile obtained by superimposing waveforms during longitudinal wave travel. Figure 5 The image shows a transverse wave scanning imaging profile obtained by superimposing waveforms during transverse wave travel.

[0202] By utilizing the time difference between the arrival times of the P-wave and the S-wave, as well as the travel times of the P-wave and the S-wave, a time-matched scanning imaging profile is obtained, such as... Figure 6 As shown. Figure 7 The image shows the final imaging profile under P-wave and S-wave constraints obtained by multiplying the P-wave scanning imaging profile and the time-matched scanning imaging profile. Figure 8 The image shows the final imaging profile under P-wave and S-wave constraints obtained by multiplying the shear wave scanning imaging profile and the time-matched scanning imaging profile.

[0203] It can be seen that the positioning accuracy of the final imaging profile constrained by P-wave and S-wave time difference in the depth direction is significantly better than that of the imaging profile obtained by simple P-wave or S-wave scanning.

[0204] Application Example 2

[0205] The microseismic source location method of this invention is applied to perform scanning and location of weak surface shallow well microseismic signals, such as... Figure 9 The image shows a weak surface shallow well microseismic signal. Figure 10 The image shows a longitudinal wave scanning imaging profile obtained by superimposing waveforms during longitudinal wave travel. Figure 11 The image shows a transverse wave scanning imaging profile obtained by superimposing waveforms during transverse wave travel.

[0206] By utilizing the time difference between the arrival times of the P-wave and the S-wave, as well as the travel times of the P-wave and the S-wave, a time-matched scanning imaging profile is obtained, such as... Figure 12 As shown. Figure 13 The image shows the final imaging profile under P-wave and S-wave constraints obtained by multiplying the P-wave scanning imaging profile and the time-matched scanning imaging profile. Figure 14The image shows the final imaging profile under P-wave and S-wave constraints obtained by multiplying the shear wave scanning imaging profile and the time-matched scanning imaging profile.

[0207] Similarly, the positioning accuracy of the final imaging profile constrained by P-wave and S-wave time difference in the depth direction is significantly better than that of the imaging profile obtained by simple P-wave or S-wave scanning.

[0208] In summary, this invention can still achieve accurate three-dimensional positioning of microseismic sources under weak microseismic signal conditions. Compared with the first arrival inversion method, it has lower requirements for the signal-to-noise ratio of microseismic signals. Compared with the waveform scanning method, it makes full use of P-wave and S-wave information, thereby improving the positioning accuracy of microseismic sources in the depth direction.

[0209] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the methods described above. Any references to memory, storage, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, or optical storage, etc. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc.

[0210] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0211] While the embodiments disclosed in this invention are as described above, the content is merely for the purpose of facilitating understanding of the invention and is not intended to limit the invention. Any person skilled in the art to which this invention pertains may make any modifications and changes in form and detail of the implementation without departing from the spirit and scope disclosed herein; however, the scope of protection of this invention shall still be determined by the scope defined in the appended claims.

Claims

1. A method for locating microseismic sources, characterized in that, include: The microseismic records, P-wave travel times, and S-wave travel times were obtained from the microseismic signals of the target monitoring area detected by multiple geophones. By superimposing the microseismic records with the P-wave travel time or the S-wave travel time, a waveform scanning imaging profile is obtained. Based on the P-wave travel time and the S-wave travel time, the initial arrival times of the P-wave and the S-wave are obtained through analysis. A time-matched scanning imaging profile is obtained using the travel time of the P-wave, the travel time of the S-wave, and the time difference between the arrival times of the P-wave and the S-wave. The time-matched scanning imaging profile is an imaging profile formed by time-matched imaging values. Obtaining the time-matched scanning imaging profile using the travel time of the P-wave, the travel time of the S-wave, and the time difference between the arrival times of the P-wave and the S-wave includes: calculating the time-matched imaging values ​​of each point vertically above the center point of the target monitoring area based on the travel time of the P-wave, the travel time of the S-wave, and the time difference between the arrival times of the P-wave and the S-wave; and monitoring the time-matched imaging values ​​of the remaining points within the target monitoring area based on the time-matched imaging values ​​of each point vertically above the center point of the target monitoring area. The final imaging profile is obtained by multiplying the waveform scanning imaging profile with the time-matched scanning imaging profile. By picking the location point of the maximum imaging value of the final imaging profile, the location of the microseismic source point in the target monitoring area is obtained.

2. The method according to claim 1, characterized in that, The waveform scanning imaging profile includes one of a P-wave scanning imaging profile formed by P-wave scanning imaging values ​​and a shear wave scanning imaging profile formed by shear wave scanning imaging values; obtaining the waveform scanning imaging profile by superimposing the microseismic records through the P-wave travel time or the shear wave travel time includes: or in, For the monitoring points of the target monitoring area Longitudinal wave scanning imaging values, The number of detectors The number of sampling points within the time window. For detector Microseismic records, For the first The time corresponding to each sampling point For monitoring points to detector During longitudinal wave travel; For the monitoring points of the target monitoring area Shear wave scanning imaging values, For monitoring points to detector During transverse wave travel.

3. The method according to claim 1, characterized in that, The analysis of the initial arrival times of the P-wave and the S-wave based on the P-wave travel time and the S-wave travel time includes: The P-wave superposition value of the superposition channel is calculated based on the P-wave travel time. The shear wave superposition value of the superposition channel is calculated based on the shear wave travel time. The arrival times of the P-wave and the S-wave are obtained by the energy ratio method based on the P-wave superposition value and the S-wave superposition value, respectively.

4. The method according to claim 3, characterized in that, The calculation of the P-wave stacking value of the stacking channel based on the P-wave travel time includes: The calculation of the shear wave superposition value of the superposition channel based on the shear wave travel time includes: in, For superimposed paths The longitudinal wave superposition value at the sampling point, The number of detectors For detector Microseismic records, For the first The time corresponding to each sampling point For the monitoring points of the target monitoring area to detector During longitudinal wave travel, For the monitoring points of the target monitoring area to detector During longitudinal wave travel; For superimposed paths Shear wave superposition value at sampling point For the monitoring points of the target monitoring area to detector During transverse wave travel, For the monitoring points of the target monitoring area to detector When traveling in transverse waves; in, The center point of the target monitoring area; detector The detector is located directly above the target monitoring area.

5. The method according to claim 3, characterized in that, The step of obtaining the first arrival times of the P-wave and the S-wave respectively using the energy ratio method based on the P-wave superposition value and the S-wave superposition value includes: Based on the P-wave superposition value and the S-wave superposition value, multiple P-wave superposition energy ratios and multiple S-wave superposition energy ratios are calculated using the long-short time window energy ratio method. Pick the maximum value among the P-wave superposition energy ratios, and obtain the initial arrival time of the P-wave based on the time corresponding to the maximum value among the P-wave superposition energy ratios; Pick the maximum value among the superimposed energy ratios of the shear waves, and obtain the initial arrival time of the shear waves based on the time corresponding to the maximum value among the superimposed energy ratios of the shear waves.

6. The method according to claim 5, characterized in that, The calculation of multiple P-wave superposition energy ratios and multiple S-wave superposition energy ratios using the long-short time window energy ratio method, based on the P-wave superposition value and the S-wave superposition value respectively, includes: in, For the first The ratio of the superimposed P-wave energy at each sampling point The number of sampling points in the short time window. The number of sampling points for the long time window. For superimposed paths The longitudinal wave superposition value at the sampling point; For the first The ratio of superimposed shear wave energy at each sampling point For superimposed paths The superposition value of the transverse waves at the sampling point.

7. The method according to claim 6, characterized in that, The step of calculating the time-matched imaging values ​​of each point vertically above the center point of the target monitoring area based on the travel time of the P-wave, the travel time of the S-wave, and the time difference between the arrival times of the P-wave and the S-wave includes: in, For the monitoring points of the target monitoring area Time-matched imaging values, The initial arrival time of the longitudinal wave is... The initial arrival time of the transverse wave is... for to detector During longitudinal wave travel, for to detector When traveling in transverse waves; in, The detector is the point perpendicular to the center of the target monitoring area. The detector is located directly above the target monitoring area.

8. The method according to claim 7, characterized in that, The monitoring of time-matched imaging values ​​of other points within the target monitoring area based on the time-matched imaging values ​​of each point vertically from the center point of the target monitoring area includes: in, express The minimum value, express The maximum value, express The minimum value, express The maximum value.

9. A microseismic source location device, characterized in that, include: The information acquisition module is used to acquire microseismic records, P-wave travel times, and S-wave travel times obtained from the microseismic signals detected by multiple detectors in the target monitoring area. The first imaging module is used to superimpose the microseismic record by the P-wave travel time or the S-wave travel time to obtain a waveform scanning imaging profile. The time analysis module is used to analyze and obtain the initial arrival time of the P-wave and the initial arrival time of the S-wave based on the P-wave travel time and the S-wave travel time. The second imaging module is used to obtain a time-matched scanning imaging profile by utilizing the travel time of the longitudinal wave, the travel time of the transverse wave, and the time difference between the arrival time of the longitudinal wave and the arrival time of the transverse wave. The imaging processing module is used to multiply the waveform scanning imaging profile with the time-matched scanning imaging profile to obtain the final imaging profile; The seismic source location module is used to pick up the location point of the maximum imaging value of the final imaging profile, and obtain the location of the microseismic source point in the target monitoring area; The time-matched scanning imaging profile is an imaging profile formed by time-matched imaging values; the second imaging module is used to: calculate the time-matched imaging values ​​of each point in the vertical direction of the center point of the target monitoring area based on the travel time of the longitudinal wave, the travel time of the transverse wave, the time difference between the arrival time of the longitudinal wave and the arrival time of the transverse wave; and monitor the time-matched imaging values ​​of the remaining points in the target monitoring area based on the time-matched imaging values ​​of each point in the vertical direction of the center point of the target monitoring area.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 8.

11. A positioning device, comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the method according to any one of claims 1 to 8.

12. A positioning system, characterized in that, It includes a detector and the positioning device of claim 11, wherein the detector is connected to the positioning device.

Images