Surface shallow well microseismic monitoring event identification technology, device, equipment and medium

Abstract

The present application provides a kind of ground shallow well microseismic monitoring event identification technology, device, equipment and medium.The identification method includes: based on the three-dimensional space scanning horizontal direction and depth direction of S wave, the event energy superposition value of each grid point at each time is obtained, and the multi-channel superposition value S (t) is calculated;The maximum value of the event energy superposition value of each grid point in space at each time is obtained, and the maximum value of the multi-channel superposition value S (t) of each point at each time is updated as M (t);The envelope B (t) of M (t) is calculated by Hilbert transform, and the maximum value of M (t) greater than B (t) in fixed time window is detected as the event in the time window.The present application establishes the microseismic judgment criterion of three-dimensional space P-S wave multi-channel superposition according to the ground shallow well microseismic monitoring mode and the three-component recording characteristics, realizes the automatic detection of microseismic event based on event similarity method, the operation speed is fast, the efficiency is high, and the microseismic event can be detected automatically and quickly.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of petroleum geophysical exploration, and particularly relates to an event identification technology based on a three-dimensional P-S wave joint ground shallow well microseismic monitoring observation mode. BACKGROUND

[0002] In recent years, microseismic monitoring has gradually become a crucial part of shale gas development, and also plays an increasingly important role in active fault research. Microseismic monitoring technology is an important means for evaluating the effect of fracturing of unconventional oil and gas wells such as shale gas. With large-scale development of unconventional resources such as shale gas, the demand for hydraulic fracturing microseismic monitoring technology and production dynamic monitoring will increase. Microseismic monitoring in shale gas development is generally divided into ground monitoring and well monitoring technology. Well monitoring technology has been relatively mature, but the number of monitoring wells, spatial distribution and the number of geophones are very limited, so its lateral resolution is low, and the monitoring cost is also high. Therefore, the current developed ground monitoring and well monitoring mode microseismic monitoring technology has problems such as high construction cost and many limited conditions for observation wells. In order to meet the needs of large-scale development of unconventional oil and gas resources such as shale gas, it is necessary to carry out research on low-cost ground shallow well microseismic monitoring technology and application.

[0003] The ground shallow well microseismic monitoring technology uses sparse layout of acquisition stations and shallow well buried geophones for monitoring. Compared with the ground line microseismic method, the signal attenuation is reduced, the environmental noise is small, and the cost is low; compared with the well microseismic monitoring method, the restriction condition is less, and the observation range is wide.

[0004] From the data structure, the ground shallow well microseismic monitoring method is a combination of ground microseismic monitoring and well microseismic monitoring. It uses a three-component geophone mode in the well, a multi-well mode on the ground, and is a full wave field recording in a three-dimensional observation system. Therefore, the format of the ground shallow well microseismic monitoring data is different from the previous two microseismic monitoring methods, and the existing microseismic monitoring signal identification method cannot meet the needs of the ground shallow well microseismic monitoring method.

[0005] Therefore, there is an urgent need in the art for a ground shallow well microseismic monitoring event identification technology. SUMMARY

[0006] In order to overcome the problems existing in the prior art, the present application provides an event identification technology based on three-dimensional P-S wave joint detection, which realizes automatic detection of ground shallow well microseismic monitoring events.

[0007] According to one aspect of the present application, a three-dimensional P-S wave joint ground shallow well microseismic monitoring event identification method is provided, comprising:

[0008] The S-wave-based three-dimensional space scanning horizontal direction and depth direction are used to obtain the event energy superposition value of each grid point at each time, and a multi-channel superposition value S(t) is calculated;

[0009] The maximum value of the event energy superposition value of each grid point at each time in the space is obtained, and the maximum value of the multi-channel superposition value S(t) of each point at each time is updated as M(t);

[0010] The Hilbert transform of M(t) is performed to calculate the envelope of M(t) as B(t),

[0011] The value of M(t) greater than the maximum value of B(t) in a fixed time window is taken as the detected event in the time window.

[0012] Further, the multi-channel superposition envelope characteristic function is used to calculate the multi-channel superposition value S(t) by using the characteristics of three-dimensional space multi-component recording of a shallow well on the ground:

[0013]

[0014] is the number of channels, is the first is the first is the time shift of the first is the time shift of the first is the time of the S-wave from the spatial point of the source to each shallow well geophone.

[0015] Further, the X component and the Y component are subjected to polarization analysis to separate the P-wave and S-wave wave fields;

[0016] For the spatial point of the possible source, the times of the P-wave and S-wave from the spatial point to each shallow well geophone are calculated.

[0017] Further, the recognition method further includes determining whether the detected event is a valid event.

[0018] Further, the position of the detected event is corrected for each monitoring channel, the corrected each monitoring channel and the adjacent channel are subjected to coherent superposition to obtain A(t), and the coherent analysis is performed on the value of M(t); the coherence coefficient is obtained

[0019] ,

[0020] In the formula, denotes the coherence coefficient of A(t) and M(t) at frequency f, and denote the power spectral density of A(t) and M(t), respectively, denotes the cross-spectral density of A(t) and M(t);

[0021] If signal =1, and M(t) is completely coherent, reflecting the similarity between signals, then it is an effective event; signal =0, and M(t) is not coherent, and is judged as an invalid event.

[0022] Further, the fixed time window is greater than the maximum time difference of S wave and P wave.

[0023] Further, the corresponding time at which the value of M(t) is greater than the maximum value of B(t) is the occurrence time of the event.

[0024] According to another aspect of the present application, there is provided a device for identifying events in shallow well microseismic monitoring on the ground based on three-dimensional longitudinal and transverse wave combination, comprising:

[0025] A calculation unit calculates the event energy superposition value of each grid point at each time based on three-dimensional spatial scanning of S wave in horizontal direction and depth direction, and calculates multi-channel superposition value S(t);

[0026] An updating unit calculates the maximum value of the event energy superposition value of each grid point at each time in space, and updates the maximum value of multi-channel superposition value S(t) of each point at each time as M(t);

[0027] An identification unit performs Hilbert transform on M(t), calculates the envelope of M(t) as B(t), and takes the value of M(t) greater than the maximum value of B(t) in a fixed time window as the detected event in the time window.

[0028] According to another aspect of the present application, there is provided an electronic device, comprising:

[0029] A memory storing executable instructions;

[0030] A processor running the executable instructions in the memory to implement the event identification method based on three-dimensional longitudinal and transverse wave combination.

[0031] According to another aspect of the present application, there is provided a computer readable storage medium storing a computer program, which is executed by a processor to implement the event identification method based on three-dimensional longitudinal and transverse wave combination.

[0032] The event identification technology based on three-dimensional spatial longitudinal and transverse wave combination detection of the present application has the following characteristics:

[0033] a) On the basis of the characteristics of P / S waves received by the three-component detector string in the three-dimensional space record: the energy of S waves is dominant in the record to establish the criterion based on the joint detection of S&P.

[0034] b) The principle of combining the corrected S wave set and the detection of the coherence analysis of the trace can quickly detect and eliminate invalid events based on the similarity principle.

[0035] c) Without manual screening and picking, the calculation efficiency is improved. BRIEF DESCRIPTION OF DRAWINGS

[0036] The above and other objects, features and advantages of the present disclosure will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings, in which like reference characters refer to like parts throughout the figures, and wherein:

[0037] Figure 1 The flow chart of the event recognition method based on the three-dimensional longitudinal and transverse wave joint ground shallow well microseismic monitoring of the present application.

[0038] Figure 2 The schematic diagram of the planar observation system for the ground shallow well microseismic monitoring according to the embodiment of the present application.

[0039] Figure 3 The schematic diagram of the simulated ground shallow well microseismic monitoring record under the observation system according to the embodiment of the present application.

[0040] Figure 4 The schematic diagram of the microseismic event recognized by the recognition algorithm according to the embodiment of the present application. DETAILED DESCRIPTION

[0041] The preferred embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the preferred embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to make the present disclosure more thorough and complete, and to fully convey the scope of the present disclosure to those skilled in the art.

[0042] The present application establishes the microseismic judgment criterion of three-dimensional space longitudinal and transverse wave multi-channel superposition according to the ground shallow well microseismic monitoring mode and the characteristics of three-component record, realizes the automatic detection of microseismic events based on the event similarity method, and has fast operation speed and high efficiency, which can quickly and automatically detect microseismic events.

[0043] The present disclosure proposes a three-dimensional longitudinal and transverse wave joint ground shallow well microseismic monitoring event recognition method, which comprises:

[0044] Based on the three-dimensional spatial scanning of S-wave in the horizontal and depth directions, the event energy superposition value at each point and time is obtained, and the multichannel superposition value S(t) is calculated.

[0045] Find the maximum value of the event energy superposition value at each point and time, and update the maximum value of the multi-channel superposition value S(t) at each time to M(t);

[0046] Perform a Hilbert transform on M(t) and calculate the envelope of M(t) as B(t). The maximum value of M(t) that is greater than B(t) within a fixed time window is taken as the event within the time window.

[0047] For surface shallow well microseismic monitoring, the number of shallow wells distributed in a plane is relatively small, each well records three components, resulting in a limited total number of channels monitored; the microseismic signals are weak, with weak P-wave energy and strong S-wave energy, making it difficult to pick up the first arrival wave. This paper adopts an energy-based approach to highlight the identifiability of the timing signals of microseismic events. Automatic event detection is performed on synthesized stacked channels, resulting in a relatively high signal-to-noise ratio.

[0048] Specifically, taking advantage of the characteristics of multi-component three-dimensional spatial records from shallow surface wells, a multi-channel superimposed envelope characteristic function is used as the judgment criterion:

[0049]

[0050] It is the Tao, For the first One detector; No. The time shift of a detector. Given a known seismic source, the time shift can be calculated.

[0051] Specifically, based on the characteristics of P / S waves received by a three-component detector string: the S-wave polarization direction is perpendicular to the propagation direction, while the P-wave polarization direction is consistent with the propagation direction; the S-wave is mainly polarized in a near-horizontal direction, while the P-wave is polarized in a near-vertical direction; the energy of the S-wave dominates in local recordings; the polarization directions of the P-wave and S-wave are orthogonal; the travel time of the same P / S wave arriving at the detector string is consistent; and the time difference between P / S waves from the same source is finite. A criterion based on joint S&P detection is established.

[0052] Next, the X and Y components are separated into P-wave and S-wave waves through polarization analysis; for a given spatial point of possible seismic source, the time of P and S waves to each shallow well detector is calculated.

[0053] Specifically, the event energy stack value of each point at each time is calculated based on the three-dimensional space scanning horizontal direction and depth direction of S wave by using the way of seismic source scanning energy stack. The maximum value of the event energy stack value of each point at each time is calculated by scanning one seismic source value, calculating the multi-channel stack value S(t), and updating the maximum value of S(t) at each time as M(t) to form a multi-channel stack monitoring channel and record the initial position of the maximum energy value at each time. M(t) stores the maximum value of the energy scanning stack in the three-dimensional space at each time.

[0054] Next, the Hilbert transform of M(t) is performed to calculate the envelope B(t) of M(t). The convolution of the function M(t) and is calculated by the formula:

[0055] .

[0056] In a fixed time window (greater than the maximum time difference of S wave and P wave), the value of M(t) greater than the maximum value of B(t) is regarded as an event in the detection window, and the corresponding time is the earthquake time of the event.

[0057] Preferably, the position of the detected event is corrected in each monitoring channel, the corrected each monitoring channel is coherently stacked with the adjacent to form A(t), and the coherence coefficient :

[0058]

[0059] In the formula, represents the coherence coefficient of A(t) and M(t) at frequency f, and respectively represent the power spectral density of A(t) and M(t), represents the cross-spectral density of A(t) and M(t);

[0060] If the signal =1, and M(t) are completely coherent, which reflects the similarity between signals, and it is an effective event; if the signal =0, and M(t) are incoherent, which is judged as an invalid event.

[0061] In order to understand the scheme and effect of the embodiments of the present application, a specific application example is given below. Those skilled in the art should understand that the example is only for the purpose of understanding the present application, and any specific details are not intended to limit the present application in any way.

[0062] Example 1

[0063] This embodiment selects a fractured well as an example to test the identification method of the present application; a grid-shaped ground shallow well microseismic monitoring observation system is designed (such as Figure 2 ) The forward source record is shown in FIG. 1. The ground shallow well microseismic processing is performed, and the event identification method is selected as the event identification method in this paper. The identified microseismic events are shown in FIG. 2. There are only 3 channels on the right side of the figure, and there are two energy superposition prominent waveform characteristics, which are P wave and S wave of a microseismic event. The first energy is P wave, and the second is S wave. Whether it is an effective event is determined by the S wave. Figure 3 Figure 4 Therefore, it is verified that the event identification method of the present application can quickly and effectively detect effective microseismic events, and has certain feasibility. In addition, in the multi-well long-term monitoring and development area stage, this ground shallow well microseismic monitoring method and identification technology has certain advantages.

[0064]

[0065] Example 2

[0066] The embodiment provides a ground shallow well microseismic monitoring event identification device based on three-dimensional P-S wave combination, which comprises:

[0067] A calculation unit is used for calculating the event energy superposition value of each grid point at each time based on the three-dimensional space scanning horizontal direction and depth direction of the S wave, and calculating the multi-channel superposition value S(t);

[0068] An updating unit is used for calculating the maximum value of the event energy superposition value of each grid point at each time in the space, and updating the maximum value of the multi-channel superposition value S(t) of each point at each time as M(t);

[0069] An identification unit is used for performing Hilbert transform on M(t), calculating the envelope B(t) of M(t), and regarding the value of M(t) greater than the maximum value of B(t) in a fixed time window as the detected event in the time window.

[0070] The calculation unit, the updating unit and the identification unit are sequentially connected in communication. The calculation unit sends the calculated multi-channel superposition value S(t) to the updating unit, and the identification unit performs operation based on M(t) obtained by the updating unit, and finally identifies the microseismic event.

[0071] Preferably, the ground shallow well microseismic monitoring event identification device of the present application can further comprise a monitoring unit for monitoring whether the detected event is an effective event. Specifically, the monitoring unit corrects the position of the detected event on each monitoring channel, performs coherent superposition on the corrected each monitoring channel and adjacent channels, performs coherent analysis on the M(t) value, and determines whether it is an effective event or an ineffective event. ​​

[0072] Example 3

[0073] The embodiment provides an electronic device, including a memory storing executable instructions; and a processor running the executable instructions in the memory to implement the three-dimensional longitudinal and transverse wave combined ground shallow well microseismic monitoring event identification method.

[0074] The electronic device according to the embodiment of the present disclosure includes a memory and a processor.

[0075] The memory is configured to store non-transitory computer-readable instructions. Specifically, the memory can include one or more computer program products, which can include various forms of computer-readable storage media, such as volatile memory and / or non-volatile memory. The volatile memory may, for example, include random access memory (RAM), cache memory, and / or the like. The non-volatile memory may, for example, include read-only memory (ROM), hard disk, flash memory, and / or the like.

[0076] The processor can be a central processing unit (CPU) or other forms of processing units having data processing and / or instruction execution capabilities, and can control other components in the electronic device to perform desired functions. In one embodiment of the present disclosure, the processor is configured to run the computer-readable instructions stored in the memory.

[0077] Those skilled in the art should understand that, in order to solve the technical problem of how to obtain a good user experience effect, the embodiment can also include well-known structures such as a communication bus, an interface, and the like, which should also be included in the protection scope of the present disclosure.

[0078] The detailed description of the embodiment can refer to the corresponding description in the foregoing embodiments, which will not be repeated here.

[0079] Example 4

[0080] The embodiment provides a computer-readable storage medium storing a computer program, the computer program being executed by a processor to implement the three-dimensional longitudinal and transverse wave combined ground shallow well microseismic monitoring event identification method.

[0081] The computer-readable storage medium according to the embodiment of the present disclosure stores non-transitory computer-readable instructions. When the non-transitory computer-readable instructions are run by a processor, all or part of the steps of the method according to the embodiments of the present disclosure are executed.

[0082] The above computer-readable storage medium includes, but is not limited to, an optical storage medium (e.g., a CD-ROM and a DVD), a magneto-optical storage medium (e.g., an MO), a magnetic storage medium (e.g., a magnetic tape or a magnetic hard disk), a medium having a built-in rewritable nonvolatile memory (e.g., a memory card), and a medium having a built-in ROM (e.g., a ROM cartridge).

[0083] Those skilled in the art will understand that the above description of the embodiments of the present application is given for the purpose of exemplifying the advantageous effects of the embodiments of the present application and is not intended to limit the embodiments of the present application to any of the examples given.

[0084] The above has described the embodiments of the present application, and the above description is exemplary and is not exhaustive and is not limited to the disclosed embodiments. Many modifications and changes are obvious to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A three-dimensional longitudinal and transverse wave combined-based ground shallow well microseismic monitoring event identification method, characterized in that, The method comprises the following steps: Based on the three-dimensional space scanning of S waves in the horizontal direction and the depth direction, the event energy stack value of each grid point at each time is calculated, and the multi-channel stack value S(t) is calculated; The maximum value of the event energy stack value of each grid point at each time in the space is calculated, and the maximum value of the multi-channel stack value S(t) of each point at each time is updated as M(t); The Hilbert transform of M(t) is performed, the envelope of M(t) is calculated as B(t), and the maximum value of M(t) greater than B(t) in a fixed time window is detected as the event in the time window; The corresponding time of the maximum value of M(t) greater than B(t) is the occurrence time of the event; The method further comprises determining whether the detected event is a valid event; In which the position of the detected event is corrected for each monitoring channel, the corrected values of each monitoring channel are coherently superimposed with the adjacent channels to A(t), and coherently analyzed with the M(t) values to obtain the coherence coefficient : wherein denotes the coherence coefficient of A(t) and M(t) at frequency f, and denotes the power spectral density of A(t) and M(t), respectively, denotes the cross-spectral density of A(t) and M(t). If signal = 1, and M(t) are completely coherent, reflecting the similarity between signals, it is an effective event; signal = 0, and M(t) are not coherent, and it is judged as an ineffective event; The fixed time window is greater than the maximum time difference between S waves and P waves.

2. The method according to claim 1, wherein, The multi-channel stack envelope characteristic function is used to calculate the multi-channel stack value S(t) by using the characteristics of three-dimensional space multi-component recording of shallow wells on the ground: is the number of traces, is the number of the first trace, is the number of the first geophone, is the number of the first geophone, is the time shift of the first geophone, is the time of S-wave arrival at each shallow well geophone from the source spatial point.

3. The method according to claim 2, wherein, The wave field of P waves and S waves is separated by polarization analysis of the X component and the Y component; For the spatial point of the possible source, the time of P waves and S waves reaching each shallow well detector is calculated.

4. A device for identifying events in shallow well microseismic monitoring on the ground based on three-dimensional longitudinal and transverse wave combination, characterized in that, The method comprises the following steps: A calculation unit calculates the event energy stack value of each grid point at each time based on the three-dimensional space scanning of S waves in the horizontal direction and the depth direction, and calculates the multi-channel stack value S(t); An updating unit calculates the maximum value of the event energy stack value of each grid point at each time in the space, and updates the maximum value of the multi-channel stack value S(t) of each point at each time as M(t); An identification unit performs the Hilbert transform of M(t), calculates the envelope of M(t) as B(t), and detects the maximum value of M(t) greater than B(t) in a fixed time window as the detected event in the time window; The corresponding time of the maximum value of M(t) greater than B(t) is the occurrence time of the event; The method further comprises determining whether the detected event is a valid event; In which the position of the detected event is corrected for each monitoring channel, the corrected values of each monitoring channel are coherently superimposed with the adjacent channels to A(t), and coherently analyzed with the M(t) values to obtain the coherence coefficient : wherein denotes the coherence coefficient of A(t) and M(t) at frequency f, and denotes the power spectral density of A(t) and M(t), respectively, denotes the cross spectral density of A(t) and M(t). If signal = 1, and M(t) are completely coherent, reflecting the similarity between signals, it is an effective event; signal = 0, and M(t) are not coherent, and it is judged as an ineffective event; The fixed time window is greater than the maximum time difference between S waves and P waves.

5. An electronic device, comprising: The electronic device comprises: A memory storing executable instructions; A processor running the executable instructions in the memory to implement the three-dimensional longitudinal and transverse wave joint-based ground shallow well microseismic monitoring event identification method in any one of claims 1-3.

6. A computer-readable storage medium, characterized in that, The computer readable storage medium stores a computer program, which is executed by a processor to implement the three-dimensional longitudinal and transverse wave joint-based ground shallow well microseismic monitoring event identification method in any one of claims 1-3.

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