A method, system, storage medium, and apparatus for imaging a fracturing fracture

Abstract

This invention provides a method, system, storage medium, and device for imaging hydraulic fracturing fractures, belonging to the field of fiber optic microseismic data processing. The method utilizes the wavefield of reflected waves associated with fractures in DAS microseismic data and employs migration imaging to image the fractures. Specifically, it includes the following steps: Step 1, acquiring DAS microseismic data; Step 2, separating direct waves and reflected waves from the DAS microseismic data; Step 3, performing migration imaging using the separated wavefields; Step 4, outputting the fracture imaging results. This invention eliminates the need for localizing microseismic events, directly imaging fractures using direct wave and reflected wavefield information. Compared to traditional microseismic monitoring, this invention can accurately describe the geometry and orientation of hydraulic fracturing fractures.

Description

Technical Field

[0001] This invention belongs to the field of fiber optic microseismic data processing, specifically relating to a method, system, storage medium, and device for imaging hydraulic fracturing fractures. Background Technology

[0002] Microseismic monitoring is a commonly used technique for evaluating the effectiveness of hydraulic fracturing. It assesses fracturing effectiveness by acquiring parameters related to microseismic events, including the triggering time, focal location, magnitude, and focal mechanism. However, relying solely on microseismic location still presents challenges in accurately describing the geometry and orientation of fractures, as well as the connectivity between fractures.

[0003] With advancements in sensing technology, Distributed Acoustic Sensing (DAS) can acquire high-density microseismic wavefield records throughout the entire wellbore during the fracturing process by deploying optical fibers in fracturing wells or adjacent wells. Monitoring close to the target reservoir with optical fibers yields richer microseismic wavefield characteristics; detailed analysis of the wavefield allows for a better interpretation of the fracturing effect. Therefore, this study aims to further investigate a method for imaging fracturing fractures using DAS microseismic data. Summary of the Invention

[0004] The purpose of this invention is to solve the problems existing in the prior art and provide a method, system, storage medium and device for imaging hydraulic fracturing fractures, which does not require the location of microseismic events and directly images the fractures using direct wave and reflected wave field information.

[0005] One of the objectives of this invention is to provide a method for imaging hydraulic fracturing cracks.

[0006] The second objective of this invention is to provide a fracturing crack imaging system.

[0007] A third objective of this invention is to provide a computer-readable storage medium.

[0008] The fourth objective of this invention is to provide a computer device.

[0009] This invention is achieved through the following technical solution:

[0010] In a first aspect, the present invention provides a method for imaging hydraulic fracturing fractures, which uses the wave field of reflected waves associated with fractures in DAS microseismic data and employs a migration imaging method to image the fractures.

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

[0012] The method specifically includes the following steps:

[0013] Step 1: Acquire DAS microseismic data;

[0014] Step 2: Separate the direct wave and reflected wave from the DAS microseismic data;

[0015] Step 3: Use the separated wavefield for offset imaging;

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

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

[0018] In step 1, the DAS microseismic data includes reflected wavefield information after reflection through the cracks, including reflected P-wave or reflected S-wave fields.

[0019] A further improvement of the present invention is that

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

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

[0022] Step 2 involves separating direct waves and reflected waves from the DAS microseismic data, specifically as follows:

[0023] Direct waves and reflected waves were separated from DAS microseismic data using a wavefield separation method.

[0024] The wave field separation method can be any one of median filtering, mean filtering, FK filtering, etc.

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

[0026] Step 3 involves using the separated wavefield for migration imaging, specifically including:

[0027] (1) Establish the migration P-wave and S-wave velocity model using acoustic logging curves;

[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 wave field back propagation algorithm, where x is the spatial position and t is the time.

[0029] (3) Imaging processing is performed using cross-correlation imaging conditions. The expression for cross-correlation imaging conditions is:

[0030]

[0031] Where I(x) is the imaging result, and D(x,t) is the back propagation wave field of the direct wave and the back propagation wave field of the reflected wave R(x,t).

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

[0033] The crack imaging results output in step 4 are as follows:

[0034] Repeat steps 2 and 3 to process each DAS microseismic data in turn. Finally, the migration imaging results of multiple DAS microseismic data are superimposed to obtain the crack imaging result.

[0035] The second objective of this invention is to provide a fracturing fracture imaging system, comprising:

[0036] Acquisition unit, used to acquire DAS microseismic data;

[0037] Separation units are used to separate direct waves and reflected waves from DAS microseismic data;

[0038] The offset imaging unit is used to perform offset imaging using the separated wavefield;

[0039] Output unit, used to output crack imaging results.

[0040] A third objective of this invention is to provide a computer-readable storage medium storing at least one computer-executable program, which, when executed by the computer, causes the computer to perform the steps in the fracturing fracture imaging method described above.

[0041] A fourth aspect of the present invention provides a computer device including a memory and a processor, the memory storing a computer program that, when executed by the processor, causes the processor to perform the steps of the fracturing fracture imaging method described above.

[0042] Compared with the prior art, the beneficial effects of the present invention are:

[0043] This invention eliminates the need to locate microseismic events, and directly images cracks using information from direct and reflected wave fields.

[0044] Compared to traditional microseismic monitoring, this invention can accurately describe the geometry and orientation of hydraulic fracturing cracks. Attached Figure Description

[0045] Figure 1 This is a flowchart of the fracturing fracture imaging method provided by the present invention;

[0046] Figure 2 This is a schematic diagram showing the positional relationship between fracturing wells and fiber optic wells;

[0047] Figure 3 It is simulated DAS microseismic wavefield data;

[0048] Figure 4 This is the result of crack imaging. Detailed Implementation

[0049] The present invention will now be described in further detail with reference to the accompanying drawings:

[0050] This invention provides a method for imaging hydraulic fracturing fractures using DAS microseismic data. The method utilizes the wave field of reflected waves associated with the fracture in the DAS microseismic data and employs a migration imaging method to image the fracture.

[0051]

Example 1

[0052] This invention provides a method for imaging hydraulic fracturing fractures, such as... Figure 1 As shown, the method specifically includes:

[0053] Step 1: Acquire DAS microseismic data;

[0054] The DAS microseismic data contains information on reflected wave fields after reflection from cracks, including reflected P-wave or reflected S-wave fields.

[0055] The DAS microseismic data are multiple.

[0056] Step 2: Separate the direct wave and reflected wave from the DAS microseismic data;

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

[0058] The wavefield separation method can be any of the following: median filtering, mean filtering, FK filtering, etc.

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

[0060] Step 3: Use the separated wavefield for offset imaging;

[0061] The specific operations include:

[0062] (1) Establish the migration P-wave and S-wave velocity model using acoustic logging curves;

[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 wave field back propagation algorithm, where x is the spatial position and t is the time.

[0064] Among them, the wavefield backpropagation algorithm can adopt any wavefield backpropagation algorithm in conventional migration imaging methods, such as the Kirchhoff integral method, the one-way wave equation method, and the two-way wave equation method. These are all existing technologies and will not be elaborated here.

[0065] (3) Imaging processing is performed using cross-correlation imaging conditions. The expression for cross-correlation imaging conditions is:

[0066]

[0067] Where I(x) is the imaging result, and D(x,t) is the back propagation wave field of the direct wave and the back propagation wave field of the reflected wave R(x,t).

[0068] Step 4: Output the crack imaging results;

[0069] Repeat steps 2 and 3 to process each DAS microseismic data in turn. Finally, the migration imaging results of multiple DAS microseismic data are superimposed to obtain the crack imaging result.

[0070] This embodiment utilizes the method of the present invention to perform crack imaging on DAS microseismic data. In this embodiment, simulated fiber optic microseismic data is used to verify the method.

[0071] Figure 2 This diagram illustrates the positional relationship between the fractured well and the fiber optic well. It also shows the ray paths of the microseismic source, the fracture, the direct microseismic wave, and the reflected wave.

[0072] Figure 3 The simulated fiber optic microseismic wave field data typically shows stronger S-wave energy in DAS microseismic data. This simulation only simulates direct S-waves and crack-reflected S-waves.

[0073] Figure 4 The image shows crack imaging results, which match the actual crack location (the simulated real crack location is a horizontal crack at a vertical coordinate of 500m). Model testing demonstrates the effectiveness of the crack imaging method of this invention.

[0074]

Example 2

[0075] This invention provides a fracturing fracture imaging system, comprising:

[0076] Acquisition unit, used to acquire DAS microseismic data;

[0077] The DAS microseismic data contains information on reflected wave fields after reflection from cracks, including reflected P-wave or reflected S-wave fields.

[0078] The DAS microseismic data are multiple.

[0079] The separation unit is used to separate direct waves and reflected waves from DAS microseismic data, and specifically performs the following operations:

[0080] The wavefield separation method was used to separate direct waves and reflected waves from DAS microseismic data.

[0081] The wavefield separation method can be any of the following: median filtering, mean filtering, FK filtering, etc.

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

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

[0084] (1) Establish the migration P-wave and S-wave velocity model using acoustic logging curves;

[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 wave field back propagation algorithm, where x is the spatial position and t is the time.

[0086] Among them, the wavefield backpropagation algorithm can adopt any wavefield backpropagation algorithm in conventional migration imaging methods, such as the Kirchhoff integral method, the one-way wave equation method, and the two-way wave equation method. These are all existing technologies and will not be elaborated here.

[0087] (3) Imaging processing is performed using cross-correlation imaging conditions. The expression for cross-correlation imaging conditions is:

[0088]

[0089] Where I(x) is the imaging result, and D(x,t) is the back propagation wave field of the direct wave and the back propagation wave field of the reflected wave R(x,t).

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

[0091] Repeat steps 2 and 3 to process each DAS microseismic data in turn. Finally, the migration imaging results of multiple DAS microseismic data are superimposed to obtain the crack imaging result.

[0092]

Example 3

[0093] This invention provides a computer-readable storage medium storing at least one computer-executable program, which, when executed by the computer, causes the computer to perform the following steps:

[0094] Step 1: Acquire DAS microseismic data;

[0095] The DAS microseismic data contains information on reflected wave fields after reflection from cracks, including reflected P-wave or reflected S-wave fields.

[0096] The DAS microseismic data are multiple.

[0097] Step 2: Separate the direct wave and reflected wave from the DAS microseismic data;

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

[0099] The wavefield separation method can be any of the following: median filtering, mean filtering, FK filtering, etc.

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

[0101] Step 3: Use the separated wavefield for offset imaging;

[0102] The specific operations include:

[0103] (1) Establish the migration P-wave and S-wave velocity model using acoustic logging curves;

[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 wave field back propagation algorithm, where x is the spatial position and t is the time.

[0105] Among them, the wavefield backpropagation algorithm can adopt any wavefield backpropagation algorithm in conventional migration imaging methods, such as the Kirchhoff integral method, the one-way wave equation method, and the two-way wave equation method. These are all existing technologies and will not be elaborated here.

[0106] (3) Imaging processing is performed using cross-correlation imaging conditions. The expression for cross-correlation imaging conditions is:

[0107]

[0108] Where I(x) is the imaging result, and D(x,t) is the back propagation wave field of the direct wave and the back propagation wave field of the reflected wave R(x,t).

[0109] Step 4: Output the crack imaging results;

[0110] Repeat steps 2 and 3 to process each DAS microseismic data in turn. Finally, the migration imaging results of multiple DAS microseismic data are superimposed to obtain the crack imaging result.

[0111]

Example 4

[0112] This invention provides a computer device, including a memory and a processor. The memory stores a computer program, and when the computer program is executed by the processor, the processor performs the following steps:

[0113] Step 1: Acquire DAS microseismic data;

[0114] The DAS microseismic data contains information on reflected wave fields after reflection from cracks, including reflected P-wave or reflected S-wave fields.

[0115] The DAS microseismic data are multiple.

[0116] Step 2: Separate the direct wave and reflected wave from the DAS microseismic data;

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

[0118] The wavefield separation method can be any of the following: median filtering, mean filtering, FK filtering, etc.

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

[0120] Step 3: Use the separated wavefield for offset imaging;

[0121] The specific operations include:

[0122] (1) Establish the migration P-wave and S-wave velocity model using acoustic logging curves;

[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 wave field back propagation algorithm, where x is the spatial position and t is the time.

[0124] Among them, the wavefield backpropagation algorithm can adopt any wavefield backpropagation algorithm in conventional migration imaging methods, such as the Kirchhoff integral method, the one-way wave equation method, and the two-way wave equation method. These are all existing technologies and will not be elaborated here.

[0125] (3) Imaging processing is performed using cross-correlation imaging conditions. The expression for cross-correlation imaging conditions is:

[0126]

[0127] Where I(x) is the imaging result, and D(x,t) is the back propagation wave field of the direct wave and the back propagation wave field of the reflected wave R(x,t).

[0128] Step 4: Output the crack imaging results;

[0129] Repeat steps 2 and 3 to process each DAS microseismic data in turn. Finally, the migration imaging results of multiple DAS microseismic data are superimposed to obtain the crack imaging result.

[0130] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments described above. Any references to memory, storage, databases, or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), dual data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), RAMbus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and RAMbus dynamic RAM (RDRAM), etc.

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

Claims

1. A method of imaging a hydraulic fracture, the method comprising: Using the wave field of reflected waves associated with cracks in DAS microseismic data, the cracks were imaged using migration imaging methods; The method specifically includes the following steps: Step 1: Acquire DAS microseismic data; Step 2: Separate the direct wave and reflected wave from the DAS microseismic data; Step 3: Perform migration imaging using the separated wavefield. Specific operations include: (1) Establish the migration P-wave and S-wave velocity model using acoustic logging curves; (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 wave field back propagation algorithm, where x is the spatial position and t is the time. (3) Imaging processing is performed using cross-correlation imaging conditions. The expression for cross-correlation imaging conditions is: Where I(x) is the imaging result, D(x,t) is the back propagation wave field of the direct wave, and R(x,t) is the back propagation wave field of the reflected wave; Step 4: Output the crack imaging results.

2. The method of imaging a fracturing fracture of claim 1, wherein, In step 1, the DAS microseismic data includes reflected wavefield information after reflection through the cracks, including reflected P-wave or reflected S-wave fields.

3. The fracturing fracture imaging method according to claim 2, characterized in that, The DAS microseismic data obtained in step 1 are multiple.

4. The fracturing fracture imaging method according to claim 1, characterized in that, Step 2 involves separating direct waves and reflected waves from the DAS microseismic data, specifically as follows: Direct waves and reflected waves were separated from DAS microseismic data using a wavefield separation method. The wave field separation method can be any one of median filtering, mean filtering, or FK filtering.

5. The fracturing fracture imaging method according to claim 1, characterized in that, The crack imaging results output in step 4 are as follows: Repeat steps 2 and 3 to process each DAS microseismic data in turn. Finally, the migration imaging results of multiple DAS microseismic data are superimposed to obtain the crack imaging result.

6. A fracturing fracture imaging system, characterized in that, include: Acquisition unit, used to acquire DAS microseismic data; Separation units are used to separate direct waves and reflected waves from DAS microseismic data; The migration imaging unit is used to perform migration imaging using the separated backpropagation wavefields of the direct wave and the reflected wave; specifically, it performs the following operations: (1) Establish the migration P-wave and S-wave velocity model using acoustic logging curves; (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 wave field back propagation algorithm, where x is the spatial position and t is the time. (3) Imaging processing is performed using cross-correlation imaging conditions. The expression for cross-correlation imaging conditions is: Where I(x) is the imaging result, D(x,t) is the back propagation wave field of the direct wave, and R(x,t) is the back propagation wave field of the reflected wave; Output unit, used to output crack imaging results.

7. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores at least one computer-executable program, which, when executed by the computer, causes the computer to perform the action claimed in claim 1.

5. The steps in the fracturing fracture imaging method described in any one of the claims.

8. A computer device, characterized in that, It includes a memory and a processor, the memory storing a computer program that, when executed by the processor, causes the processor to perform as claimed in claim 1.

5. The steps of the fracturing fracture imaging method described in any one of the claims.

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