Fracturing crack imaging method and system, storage medium and equipment

Abstract

The invention provides a fracturing crack imaging method and system, a storage medium and equipment, and belongs to the field of optical fiber microseismic data processing. According to the method, reflection wave fields related to cracks in DAS microseismic data are utilized, the cracks are imaged through a migration imaging method, and the method specifically comprises the following steps that 1, the DAS microseismic data are obtained; 2, separating direct waves and reflected waves from the DAS microseismic data; step 3, carrying out migration imaging by using the separated wave field; and step 4, outputting a crack imaging result. According to the method, the micro-seismic event does not need to be positioned, and the crack is directly imaged by using the direct wave and reflected wave field information; compared with traditional microseism monitoring, the method can accurately describe the geometrical morphology and orientation of the fracturing crack.

Description

Technical Field

[0001] The present invention belongs to the field of optical fiber microseismic data processing, and in particular relates to a fracturing crack imaging method, system, storage medium and equipment. Background Art

[0002] Microseismic monitoring technology is currently a common technology for evaluating the effect of hydraulic fracturing. Fracturing microseismic monitoring evaluates the effect of hydraulic fracturing by obtaining parameters related to microseismic events, including the excitation time, source location, magnitude and source mechanism of microseismic events; however, there are still challenges in accurately describing the geometry and orientation of fractures and the connectivity between fractures through microseismic positioning alone.

[0003] With the advancement of sensing technology, distributed acoustic sensing technology (DAS) can collect full-well section and high-density fracturing microseismic wave field records during fracturing by laying optical fibers in fracturing wells or adjacent wells. The optical fiber is close to the target reservoir for monitoring, and the microseismic wave field characteristics are richer; through detailed analysis of the wave field, the fracturing transformation effect can be better explained. Therefore, a method for imaging fracturing cracks using DAS microseismic data is continued. Summary of the invention

[0004] The purpose of the present invention is to solve the above-mentioned problems existing in the prior art and to provide a method, system, storage medium and device for imaging fracturing cracks, which do not require the positioning of microseismic events and directly image the cracks using direct wave and reflected wave field information.

[0005] One of the purposes of the present invention is to provide a method for imaging a hydraulic fracture.

[0006] A second object of the present invention is to provide a fracturing crack imaging system.

[0007] A third object of the present invention is to provide a computer-readable storage medium.

[0008] A fourth object of the present invention is to provide a computer device.

[0009] The present invention is achieved through the following technical solutions:

[0010] A first aspect of the present invention provides a method for imaging a hydraulic fracture, which utilizes the reflection wave field associated with the fracture in DAS microseismic data and adopts a migration imaging method to image the fracture.

[0011] A further improvement of the present invention is:

[0012] The method specifically comprises the following steps:

[0013] Step 1, obtaining DAS microseismic data;

[0014] Step 2, separate direct waves and reflected waves from DAS microseismic data;

[0015] Step 3, using the separated wave field to perform migration imaging;

[0016] Step 4: Output the crack imaging results.

[0017] A further improvement of the present invention is:

[0018] In step 1, the DAS microseismic data includes reflection wave field information reflected by the fracture, including reflection P wave or reflection S wave field.

[0019] A further improvement of the present invention is

[0020] The DAS microseismic data acquired in step 1 are multiple.

[0021] A further improvement of the present invention is:

[0022] In step 2, direct waves and reflected waves are separated from the DAS microseismic data, specifically:

[0023] The wave field separation method is used to separate the direct wave and the reflected wave from the DAS microseismic data;

[0024] The wave field separation method is any one of median filtering, mean filtering, FK and the like.

[0025] A further improvement of the present invention is:

[0026] In step 3, the separated wave field is used to perform migration imaging, and the specific operations include:

[0027] (1) Using acoustic logging curves to establish the migration P- and S-wave velocity models;

[0028] (2) The back propagation wave field D(x, t) of the direct wave and the back propagation wave field R(x, t) of the reflected wave are calculated using the back propagation wave field algorithm, where x is the spatial position and t is the time.

[0029] (3) The cross-correlation imaging condition is used for imaging processing. The cross-correlation imaging condition expression is:

[0030]

[0031] Among them, I(x) is the imaging result, D(x, t) is the back-propagation wavefield of the direct wave and R(x, t) is the back-propagation wavefield of the reflected wave.

[0032] A further improvement of the present invention is:

[0033] The crack imaging result is output in step 4, specifically:

[0034] Repeat steps 2 and 3 to perform imaging processing on each DAS microseismic data in turn, and finally superimpose the migration imaging results of multiple DAS microseismic data to obtain the fracture imaging results.

[0035] A second object of the present invention is to provide a fracturing crack imaging system, comprising:

[0036] An acquisition unit, used for acquiring DAS microseismic data;

[0037] A separation unit, used to separate direct waves and reflected waves from DAS microseismic data;

[0038] A migration imaging unit, used for performing migration imaging using the separated wave field;

[0039] The output unit is used to output the crack imaging results.

[0040] A third object of the present invention is to provide a computer-readable storage medium, wherein the computer-readable storage medium stores at least one computer-executable program, and when the at least one program is executed by the computer, the computer executes the steps in the fracturing crack imaging method as described above.

[0041] A fourth aspect of the present invention provides a computer device, comprising a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the steps of the fracturing crack imaging method as described above.

[0042] Compared with the prior art, the present invention has the following beneficial effects:

[0043] The present invention does not need to locate the microseismic events, and directly images the cracks using the direct wave and reflected wave field information.

[0044] Compared with traditional microseismic monitoring, the present invention can accurately describe the geometry and orientation of hydraulic fractures. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 is a flow chart of the fracturing crack imaging method provided by the present invention;

[0046] Figure 2 It is a schematic diagram of the positional relationship between the fracturing well and the optical fiber well;

[0047] Figure 3 It is the simulated DAS microseismic wave field data;

[0048] Figure 4 It is the crack imaging result. DETAILED DESCRIPTION

[0049] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0050] The present invention provides a method for imaging fracturing cracks using DAS microseismic data, which uses a reflection wave field associated with the cracks in the DAS microseismic data and adopts a migration imaging method to image the cracks.

[0051] [Example 1]

[0052] The embodiment of the present invention provides a method for imaging a fracturing crack. Figure 1 As shown, the method specifically includes:

[0053] Step 1, obtaining DAS microseismic data;

[0054] The DAS microseismic data contains reflection wave field information reflected by the fracture, including reflection P wave or reflection S wave field.

[0055] The DAS microseismic data are multiple.

[0056] Step 2, separate direct waves and reflected waves from DAS microseismic data;

[0057] Specifically, the wave field separation method is used to separate the direct wave and the reflected wave from the DAS microseismic data.

[0058] The wave field separation method may be any wave field separation filtering method such as median filtering, mean filtering, FK, etc.

[0059] Among them, median filtering, mean filtering, and FK are all existing technologies and will not be described in detail here.

[0060] Step 3, using the separated wave field to perform migration imaging;

[0061] Specific operations include:

[0062] (1) Using acoustic logging curves to establish the migration P- and S-wave velocity models;

[0063] (2) The back propagation wave field D(x, t) of the direct wave and the back propagation wave field R(x, t) of the reflected wave are calculated using the back propagation wave field algorithm, where x is the spatial position and t is the time.

[0064] Among them, the wave field back propagation algorithm can adopt any wave field back propagation algorithm such as Kirchhoff integration method, one-way wave equation method, two-way wave equation method in conventional migration imaging method, which are all existing technologies and will not be described in detail here.

[0065] (3) The cross-correlation imaging condition is used for imaging processing. The cross-correlation imaging condition expression is:

[0066]

[0067] Among them, I(x) is the imaging result, D(x, t) is the back-propagation wavefield of the direct wave and R(x, t) is the back-propagation wavefield of the reflected wave.

[0068] Step 4, output the crack imaging results;

[0069] Repeat steps 2 and 3 to perform imaging processing on each DAS microseismic data in turn, and finally superimpose the migration imaging results of multiple DAS microseismic data to obtain the fracture imaging results.

[0070] This embodiment uses the DAS microseismic data of the method of the present invention to perform fracture imaging. In this embodiment, simulated optical fiber microseismic data is used to verify the method.

[0071] Figure 2 It is a schematic diagram of the positional relationship between the fracturing well and the optical fiber well. The figure also illustrates the microseismic source, cracks, and the ray paths of the microseismic direct wave and reflected wave.

[0072] Figure 3 This is the simulated fiber optic microseismic wave field data. Usually, the S-wave energy in DAS microseismic data is relatively stronger. Only the direct S-wave and the fracture reflected S-wave are simulated in this simulation data.

[0073] Figure 4 The imaging result is consistent with the actual crack position (the simulated real crack position is the horizontal crack at the vertical coordinate of 500m). The model test shows the effectiveness of the crack imaging method of the present invention.

[0074] [Example 2]

[0075] An embodiment of the present invention provides a fracturing crack imaging system, comprising:

[0076] An acquisition unit, used for acquiring DAS microseismic data;

[0077] The DAS microseismic data contains reflection wave field information reflected by the fracture, including reflection P wave or reflection S wave field.

[0078] The DAS microseismic data are multiple.

[0079] The separation unit is used to separate the direct wave and the reflected wave from the DAS microseismic data. Specifically, the following operations are performed:

[0080] The wavefield separation method is used to separate the direct wave and the reflected wave from the DAS microseismic data.

[0081] The wave field separation method may be any wave field separation filtering method such as median filtering, mean filtering, FK, etc.

[0082] Among them, median filtering, mean filtering, and FK are all existing technologies and will not be described in detail here.

[0083] The migration imaging unit is used to perform migration imaging using the separated wave field, and specifically performs the following operations:

[0084] (1) Using acoustic logging curves to establish the migration P- and S-wave velocity models;

[0085] (2) The back propagation wave field D(x, t) of the direct wave and the back propagation wave field R(x, t) of the reflected wave are calculated using the back propagation wave field algorithm, where x is the spatial position and t is the time.

[0086] Among them, the wave field back propagation algorithm can adopt any wave field back propagation algorithm such as Kirchhoff integration method, one-way wave equation method, two-way wave equation method in conventional migration imaging method, which are all existing technologies and will not be described in detail here.

[0087] (3) The cross-correlation imaging condition is used for imaging processing. The cross-correlation imaging condition expression is:

[0088]

[0089] Among them, I(x) is the imaging result, D(x, t) is the back-propagation wavefield of the direct wave and R(x, t) is the back-propagation wavefield of the reflected wave.

[0090] The output unit is used to output the crack imaging results, and specifically performs the following operations:

[0091] Repeat steps 2 and 3 to perform imaging processing on each DAS microseismic data in turn, and finally superimpose the migration imaging results of multiple DAS microseismic data to obtain the fracture imaging results.

[0092] [Example 3]

[0093] An embodiment of the present invention provides a computer-readable storage medium, wherein the computer-readable storage medium stores at least one program executable by a computer, and when the at least one program is executed by the computer, the computer performs the following steps:

[0094] Step 1, obtaining DAS microseismic data;

[0095] The DAS microseismic data contains reflection wave field information reflected by the fracture, including reflection P wave or reflection S wave field.

[0096] The DAS microseismic data are multiple.

[0097] Step 2, separate direct waves and reflected waves from DAS microseismic data;

[0098] Specifically, the wave field separation method is used to separate the direct wave and the reflected wave from the DAS microseismic data.

[0099] The wave field separation method may be any wave field separation filtering method such as median filtering, mean filtering, FK, etc.

[0100] Among them, median filtering, mean filtering, and FK are all existing technologies and will not be described in detail here.

[0101] Step 3, using the separated wave field to perform migration imaging;

[0102] Specific operations include:

[0103] (1) Using acoustic logging curves to establish the migration P- and S-wave velocity models;

[0104] (2) The back propagation wave field D(x, t) of the direct wave and the back propagation wave field R(x, t) of the reflected wave are calculated using the back propagation wave field algorithm, where x is the spatial position and t is the time.

[0105] Among them, the wave field back propagation algorithm can adopt any wave field back propagation algorithm such as Kirchhoff integration method, one-way wave equation method, two-way wave equation method in conventional migration imaging method, which are all existing technologies and will not be described in detail here.

[0106] (3) The cross-correlation imaging condition is used for imaging processing. The cross-correlation imaging condition expression is:

[0107]

[0108] Among them, I(x) is the imaging result, D(x, t) is the back-propagation wavefield of the direct wave and R(x, t) is the back-propagation wavefield of the reflected wave.

[0109] Step 4, output the crack imaging results;

[0110] Repeat steps 2 and 3 to perform imaging processing on each DAS microseismic data in turn, and finally superimpose the migration imaging results of multiple DAS microseismic data to obtain the fracture imaging results.

[0111] [Example 4]

[0112] An embodiment of the present invention provides a computer device, including a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the following steps:

[0113] Step 1, obtaining DAS microseismic data;

[0114] The DAS microseismic data contains reflection wave field information reflected by the fracture, including reflection P wave or reflection S wave field.

[0115] The DAS microseismic data are multiple.

[0116] Step 2, separate direct waves and reflected waves from DAS microseismic data;

[0117] Specifically, the wave field separation method is used to separate the direct wave and the reflected wave from the DAS microseismic data.

[0118] The wave field separation method may be any wave field separation filtering method such as median filtering, mean filtering, FK, etc.

[0119] Among them, median filtering, mean filtering, and FK are all existing technologies and will not be described in detail here.

[0120] Step 3, using the separated wave field to perform migration imaging;

[0121] Specific operations include:

[0122] (1) Using acoustic logging curves to establish the migration P- and S-wave velocity models;

[0123] (2) The back propagation wave field D(x, t) of the direct wave and the back propagation wave field R(x, t) of the reflected wave are calculated using the back propagation wave field algorithm, where x is the spatial position and t is the time.

[0124] Among them, the wave field back propagation algorithm can adopt any wave field back propagation algorithm such as Kirchhoff integration method, one-way wave equation method, two-way wave equation method in conventional migration imaging method, which are all existing technologies and will not be described in detail here.

[0125] (3) The cross-correlation imaging condition is used for imaging processing. The cross-correlation imaging condition expression is:

[0126]

[0127] Among them, I(x) is the imaging result, D(x, t) is the back-propagation wavefield of the direct wave and R(x, t) is the back-propagation wavefield of the reflected wave.

[0128] Step 4, output the crack imaging results;

[0129] Repeat steps 2 and 3 to perform imaging processing on each DAS microseismic data in turn, and finally superimpose the migration imaging results of multiple DAS microseismic data to obtain the fracture imaging results.

[0130] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the program can be stored in a non-volatile computer-readable storage medium. When the program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. As an illustration and not limitation, RAM is available in many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0131] The above technical solution is only one implementation mode of the present invention. For those skilled in the art, it is easy to make various types of improvements or modifications based on the principles disclosed in the present invention, and it is not limited to the technical solution described in the above specific embodiments of the present invention. Therefore, the above description is only preferred and does not have a restrictive meaning.

Claims

1. A method for imaging a hydraulic fracture, characterized in that: The fractures are imaged using the migration imaging method using the reflection wave field associated with the fractures in the DAS microseismic data.

2. The method for imaging a hydraulic fracture according to claim 1, characterized in that: The method specifically comprises the following steps: Step 1, obtaining DAS microseismic data; Step 2, separate direct waves and reflected waves from DAS microseismic data; Step 3, using the separated wave field to perform migration imaging; Step 4: Output the crack imaging results.

3. The method for imaging a hydraulic fracture according to claim 2, characterized in that: In step 1, the DAS microseismic data includes reflection wave field information reflected by the fracture, including reflection P wave or reflection S wave field.

4. The method for imaging a hydraulic fracture according to claim 3, characterized in that: The DAS microseismic data acquired in step 1 are multiple.

5. The method for imaging a hydraulic fracture according to claim 2, characterized in that: In step 2, direct waves and reflected waves are separated from the DAS microseismic data, specifically: The wave field separation method is used to separate the direct wave and the reflected wave from the DAS microseismic data; The wave field separation method is any one of median filtering, mean filtering, FK and the like.

6. The method for imaging a hydraulic fracture according to claim 2, characterized in that: In step 3, the separated wave field is used to perform migration imaging, and the specific operations include: (1) Using acoustic logging curves to establish the migration P- and S-wave velocity models; (2) The back propagation wave field D(x, t) of the direct wave and the back propagation wave field R(x, t) of the reflected wave are calculated using the back propagation wave field algorithm, where x is the spatial position and t is the time. (3) The cross-correlation imaging condition is used for imaging processing. The cross-correlation imaging condition expression is: Among them, I(x) is the imaging result, D(x, t) is the reverse propagation wave field of the direct wave, and R(x, t) is the reverse propagation wave field of the reflected wave.

7. The method for imaging a hydraulic fracture according to claim 2, characterized in that: The crack imaging result is output in step 4, specifically: Repeat steps 2 and 3 to perform imaging processing on each DAS microseismic data in turn, and finally superimpose the migration imaging results of multiple DAS microseismic data to obtain the fracture imaging results.

8. A fracturing crack imaging system, characterized in that: include: An acquisition unit, used for acquiring DAS microseismic data; A separation unit, used to separate direct waves and reflected waves from DAS microseismic data; A migration imaging unit, used for performing migration imaging using the separated wave field; The output unit is used to output the crack imaging results.

9. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores at least one computer-executable program, and when the at least one program is executed by the computer, the computer executes the steps in the fracturing crack imaging method according to any one of claims 1 to 7.

10. A computer device, characterized in that: The method comprises a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the steps of the fracturing crack imaging method according to any one of claims 1 to 7.

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