Method and device for inverting formation wave impedance using DAS well seismic data

Abstract

The present invention relates to the technical field of optical fiber sensing and borehole seismic exploration, and an embodiment thereof provides a method and device for inverting formation wave impedance using DAS borehole seismic data. The method for inverting formation wave impedance using DAS borehole seismic data includes: obtaining the first arrival amplitude in a time window after the first arrival time of borehole seismic wave field data; mapping the first arrival amplitude into relative wave impedance; and correcting the relative wave impedance to obtain the inverted wave impedance. The embodiment provided by the present invention can effectively overcome the multi-solution problem of inverting wave impedance using seismic profiles.

Description

Technical Field

[0001] The present invention relates to the technical field of optical fiber sensing and borehole seismic exploration, and in particular to a method for inverting formation wave impedance using DAS borehole seismic data, a device for inverting formation wave impedance using DAS borehole seismic data, a device for inverting formation wave impedance using DAS borehole seismic data, and a corresponding storage medium. Background Art

[0002] DAS (Distributed fiber Acoustic Sensing) technology is being used more and more widely in VSP (Vertical Seismic Profiling) exploration. Compared with conventional geophone acquisition, it has significant advantages such as high-density sampling, high temperature and high pressure resistance, full-well acquisition, and good sub-wave consistency. Fiber optic acoustic sensing technology mainly uses the Rayleigh backscattering generated when the laser pulse propagates in the optical fiber. When the formation around the optical fiber vibrates, the Rayleigh scattering will carry information about the vibration changes of the formation. Through continuous observation of the fiber optic DAS in the well and phase demodulation of this optical signal, the direct seismic wave and reflected wave information of the formation can be obtained.

[0003] DAS technology is more suitable for observing seismic waves in wells. When the optical fiber is permanently laid outside the casing, it can obtain rich formation information due to direct coupling with the formation. How to effectively use the high-density information of fiber-optic acoustic sensor data to invert formation parameters is a difficult point in seismic exploration. Surveys show that at present, the formation velocity and Q value are generally obtained based on the first arrival time of the direct wave. There is currently no method to directly invert the wave impedance using the high-density DAS data direct wave. The existing methods still have many shortcomings in practical applications. How to effectively use the high-density advantage of optical fiber acquisition of seismic data in wells to invert high-precision formation wave impedance is very urgent. Summary of the invention

[0004] The purpose of the embodiment of the present invention is to provide a method and device for inverting formation wave impedance using DAS downhole seismic data. It utilizes the high-density characteristics of optical fiber seismic data acquisition, picks up first arrivals with high precision, and uses the first arrival amplitude information to invert formation wave impedance. The purpose is to invert high-precision formation wave impedance through downhole seismic data acquired by optical fiber in the well, thereby improving the ability to describe reservoir parameters and improving the application effect of seismic exploration. The implementation method provided by the method is also applicable to the formation wave impedance inversion process of downhole seismic data acquired by other methods.

[0005] In order to achieve the above-mentioned purpose, the first aspect of the present invention provides a method for inverting formation wave impedance using DAS in-hole seismic data, the method comprising: obtaining the first arrival amplitude in a time window after the first arrival time of the in-hole seismic wave field data; mapping the first arrival amplitude into relative wave impedance; and correcting the relative wave impedance to obtain the inverted wave impedance.

[0006] Preferably, the method further comprises: for multiple times collected borehole seismic wave field data or different time window lengths of the same borehole seismic wave field data, the following steps can be repeated multiple times to obtain multiple corresponding inversion wave impedances: obtaining the first arrival amplitude in the time window after the first arrival time of the borehole seismic wave field data; mapping the obtained first arrival amplitude to the corresponding relative wave impedance; correcting the relative wave impedance to obtain the corresponding inversion wave impedance; and obtaining the final inversion wave impedance by a statistical method for the obtained multiple inversion wave impedances.

[0007] Preferably, obtaining the first arrival amplitude in a time window after the first arrival time includes: obtaining the seismic wave field data in the well excited by the earthquake source; processing the seismic wave field data in the well, and determining the first arrival time by using the first arrival picking method; extracting the first arrival amplitude A by taking a time window backward from the first arrival time. i , i is the corresponding track number.

[0008] Preferably, the acquisition of the in-well seismic wave field data excited by the seismic source comprises: using a fiber optic acoustic wave sensing acquisition instrument, laying an optical cable for receiving outside the casing in the well, using an explosive seismic source or an artificial controllable seismic source to excite on the ground or in the well, and acquiring the in-well seismic wave field data.

[0009] Preferably, the method further comprises: performing spherical diffusion compensation on the first-arrival amplitude before mapping the first-arrival amplitude to the relative wave impedance.

[0010] Preferably, the relative wave impedance is corrected to obtain the inverse wave impedance, comprising:

[0011] I DAS =a×I r +b; where I DAS is the inverse wave impedance, I r is the relative wave impedance, a and b are the preset correction coefficients.

[0012] Preferably, the correction coefficients a and b are determined by the following steps: calculating the wave impedance of the corresponding well section through existing logging data; making a cross plot of the wave impedance and the calculated relative wave impedance; and obtaining the correction coefficients a and b through linear fitting.

[0013] In the second aspect of the present invention, there is also provided a device for inverting formation wave impedance using DAS in-well seismic data, the device comprising: an amplitude acquisition module for acquiring the first arrival amplitude in a time window after the first arrival time of the in-well seismic wave field data; an impedance mapping module for mapping the first arrival amplitude into a relative wave impedance; and an impedance correction module for correcting the relative wave impedance to obtain an inverted wave impedance.

[0014] Preferably, the device further comprises: for multiple times collected in-well seismic wave field data or different time window lengths of the same in-well seismic wave field data, the following steps can be repeated multiple times to obtain corresponding multiple inversion wave impedances: obtaining the first arrival amplitude in the time window after the first arrival time of the in-well seismic wave field data; mapping the obtained first arrival amplitude to the corresponding relative wave impedance; correcting the relative wave impedance to obtain the corresponding inversion wave impedance; and obtaining the final inversion wave impedance by a statistical method for the obtained multiple inversion wave impedances.

[0015] Preferably, obtaining the first arrival amplitude in a time window after the first arrival time includes: obtaining the seismic wave field data in the well excited by the earthquake source; processing the seismic wave field data in the well, and determining the first arrival time by using the first arrival picking method; extracting the first arrival amplitude A by taking a time window backward from the first arrival time. i , i is the corresponding track number.

[0016] Preferably, before adopting the first arrival picking method to determine the first arrival time, the device further comprises: adopting a multi-channel velocity filtering algorithm to remove upgoing waves in the seismic wave field data in the well.

[0017] Preferably, after acquiring the first-arrival amplitude obtained by statistics of a time window after the first-arrival time, the method further comprises: performing spherical diffusion compensation on the first-arrival amplitude.

[0018] Preferably, the relative wave impedance is corrected to obtain the inverse wave impedance, comprising:

[0019] I DAS =a×I r +b; where I DAS is the inverse wave impedance, I r is the relative wave impedance, a and b are the preset correction coefficients.

[0020] Preferably, the correction coefficients a and b are determined by the following steps: calculating the wave impedance of the corresponding well section through existing logging data, and making a cross plot of the wave impedance and the calculated relative wave impedance; and obtaining the correction coefficients a and b through linear fitting.

[0021] In the third aspect of the present invention, there is provided a device for inverting formation wave impedance using seismic data in a DAS well, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the aforementioned method for inverting formation wave impedance using seismic data in a DAS well when executing the computer program.

[0022] In a fourth aspect of the present invention, a computer-readable storage medium is provided, wherein instructions are stored in the storage medium, and when the instructions are executed on a computer, the computer executes the aforementioned method of inverting formation wave impedance using seismic data in a DAS well.

[0023] In a fifth aspect of the present invention, a computer program product is provided, comprising a computer program, which, when executed by a processor, implements the aforementioned method of inverting formation wave impedance using seismic data in a DAS well.

[0024] The above technical solution has the following beneficial effects:

[0025] The embodiment of the present invention is a method for first-arrival picking of seismic data collected by high-density optical fiber and counting the amplitude of the first-arrival time window, and obtaining formation wave impedance information through inversion. The method can effectively overcome the multi-solution problem of wave impedance inversion using seismic profiles, significantly improve the accuracy of wave impedance, and achieve a resolution of meters or even higher, thus providing a guarantee for subsequent reservoir interpretation.

[0026] Other features and advantages of the embodiments of the present invention will be described in detail in the subsequent detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The accompanying drawings are used to provide a further understanding of the embodiments of the present invention and constitute a part of the specification. Together with the following specific implementations, they are used to explain the embodiments of the present invention, but do not constitute a limitation on the embodiments of the present invention. In the accompanying drawings:

[0028] Figure 1 The schematic diagram schematically shows the steps of a method for inverting formation wave impedance using seismic data in a DAS well according to an embodiment of the present application;

[0029] Figure 2 A schematic diagram of zero-well source distance DAS-VSP recording according to an embodiment of the present application is schematically shown;

[0030] Figure 3 A schematic diagram schematically shows the inversion wave impedance of the first arrival amplitude according to an embodiment of the present application;

[0031] Figure 4 A schematic diagram schematically shows the wave impedance obtained by well logging according to an embodiment of the present application;

[0032] Figure 5 The schematic diagram of the structure of the device for inverting formation wave impedance from seismic data in a DAS well according to an embodiment of the present application is shown. DETAILED DESCRIPTION

[0033] The specific implementation of the embodiment of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the embodiment of the present invention, and is not used to limit the embodiment of the present invention.

[0034] The acquisition, storage, use, and processing of data in the technical solution of this application comply with the relevant provisions of national laws and regulations.

[0035] Figure 1 The following is a schematic diagram showing the steps of a method for inverting formation wave impedance using seismic data in a DAS well according to an embodiment of the present application. Figure 1 As shown, in one embodiment of the present application, a method for inverting formation wave impedance using seismic data in a DAS well is provided, the method comprising:

[0036] 101. Obtain the first arrival amplitude in a time window after the first arrival time of the seismic wave field data in the well;

[0037] 102. Mapping the first arrival amplitude into relative wave impedance;

[0038] 103. After correcting the relative wave impedance, an inverse wave impedance is obtained.

[0039] In this embodiment, the first arrival time can be picked up by using a variety of computer algorithms for picking up the first arrival time in the prior art. After the first arrival time, a short time window is taken to extract the first arrival amplitude, and the first arrival amplitude can be a root mean square amplitude or an average amplitude. According to the inverse proportional relationship between amplitude and impedance (the larger the impedance, the smaller the amplitude), the first arrival amplitude is mapped to relative wave impedance by taking the inverse. However, the relative wave impedance obtained at this time lacks a direct correlation with the actual wave impedance of the corresponding well section, and cannot reflect the actual size and range of the wave impedance of the specific corresponding well section. Therefore, there is a large error and correction is required. In this embodiment, the relative wave impedance is corrected according to the correction model to obtain the inversion wave impedance, thereby improving the measurement accuracy of the inversion wave impedance.

[0040] Through the above methods, the multi-solution problem of wave impedance inversion using seismic profiles can be effectively overcome, and the accuracy of wave impedance can be significantly improved. The resolution can reach meter level or even higher, providing a guarantee for subsequent reservoir interpretation.

[0041] In some embodiments provided by the present invention, the method further comprises: for multiple acquired borehole seismic wave field data or different time window lengths of the same borehole seismic wave field data, the following steps can be repeated multiple times to obtain multiple corresponding inversion wave impedances: obtaining the first arrival amplitude in the time window after the first arrival time of the borehole seismic wave field data; mapping the acquired first arrival amplitude to the corresponding relative wave impedance; correcting the relative wave impedance to obtain the corresponding inversion wave impedance; and obtaining the final inversion wave impedance by statistical methods for the obtained multiple inversion wave impedances. Each repeated process needs to re-acquire the first arrival time of the borehole seismic wave field data and perform subsequent processing steps according to different borehole seismic wave field data. The different borehole seismic wave field data here include but are not limited to multiple acquired borehole seismic wave field data or different time window lengths of the same borehole seismic wave field data. Each execution of the method will obtain an inversion wave impedance, and the multiple inversion wave impedances obtained by multiple executions will obtain the final inversion wave impedance by statistical methods. The statistical methods here include arithmetic mean method, weighted mean method or median method, etc. Through this implementation, the random error caused by a single inversion wave impedance test can be avoided.

[0042] In some embodiments provided by the present invention, obtaining the first arrival amplitude in the time window after the first arrival time includes: obtaining the well seismic wave field data excited by the earthquake source; for example: using a fiber optic acoustic wave sensor acquisition instrument, laying an optical cable outside the casing in the well for receiving, using an explosive source or an artificial controllable source to excite on the ground or in the well, and acquiring the well seismic wave field data. The selected parameters can be: laying an optical cable outside the casing in the well to 2620 meters for receiving, selecting an excitation point 60 meters near the wellhead, etc. The well seismic wave field data acquired is as follows: Figure 2 shown. Figure 2 The schematic diagram of zero-well source distance DAS-VSP recording according to an embodiment of the present application is schematically shown.

[0043] The collected in-well seismic wave field data is processed, and the first arrival time is determined by using the first arrival picking method; the first arrival picking method of this embodiment includes the maximum energy method, the long-short time window ratio method, the cross-correlation method, the phase tracking method, etc. Those skilled in the art can select one or use a combination of multiple methods according to the actual scenario.

[0044] Take a time window backward from the first arrival time to extract the first arrival amplitude A i , i is the corresponding track number, and its value is a natural number such as 1, 2, ... Through the above implementation method, the first arrival amplitudes of all observation points can be obtained.

[0045] In order to obtain a more accurate first arrival time, this embodiment pre-processes the collected well seismic wave field data before using the first arrival picking method to determine the first arrival time. This embodiment uses a multi-channel velocity filtering algorithm to remove the upgoing waves in the seismic wave. The filtering algorithm here includes methods such as median filtering or mean filtering.

[0046] In order to obtain a more accurate first-arrival amplitude, this embodiment performs preprocessing before mapping the first-arrival amplitude to relative wave impedance. This embodiment performs spherical diffusion compensation on the first-arrival amplitude Ai obtained by statistics to eliminate the influence of amplitude change caused by spherical diffusion. Reasonable spherical diffusion compensation is one of the important factors in relative amplitude maintenance processing. By setting the spherical diffusion compensation factor of the horizontal interface reflection wave at any given offset in a continuous medium whose wave velocity increases linearly with depth, spherical diffusion compensation of the first-arrival amplitude can be achieved.

[0047] In some embodiments provided by the present invention, the relative wave impedance is corrected to obtain the inverse wave impedance, comprising: DAS =a×I r +b; where I DAS is the inverse wave impedance, I r is the relative wave impedance, and the correction coefficients a and b are preset parameters. This embodiment provides a first-order linear compensation method. That is, the relative wave impedance is corrected by a first-order linear function to obtain the inverse wave impedance. The obtained inverse wave impedance is as follows: Figure 3 As shown, Figure 3 The schematic diagram of the inversion wave impedance of the first arrival amplitude according to the embodiment of the present application is schematically shown. By setting reasonable correction coefficients a and b, the obtained inversion wave impedance can more accurately reflect the actual geological conditions, thereby improving the accuracy of the wave impedance.

[0048] In some embodiments provided by the present invention, the correction coefficients a and b are determined by the following steps: calculating the wave impedance of the corresponding well section by using the existing logging data, and obtaining the data such as Figure 4 shown. Figure 4 The schematic diagram of the wave impedance obtained by logging according to the embodiment of the present application is schematically shown. The wave impedance and the calculated relative wave impedance are made into an intersection diagram. The intersection diagram method refers to a graphical interpretation technique for analyzing the correlation between multiple parameters. It intersects two types of data on a plane graph, and the linear relationship between the two and the corresponding parameter values ​​can be obtained based on the double-parameter linear fitting of the intersection diagram. In this embodiment, the correction coefficients a and b are obtained based on the linear fitting between the wave impedance obtained by logging and the calculated relative wave impedance. Linear regression can be used here to obtain the actual values ​​of the correction coefficients a and b. The correction coefficients a and b are represented in the coordinate system as follows: a is the slope of the linear correction, and b is the intercept of the linear correction.

[0049] In some optional embodiments provided by the present invention, the method for inverting formation wave impedance using seismic data in a DAS well comprises the following steps:

[0050] 1) Using the fiber optic acoustic wave sensor acquisition instrument, the optical cable is laid outside the casing in the well to 2620 meters for receiving. The excitation point is selected 60 meters near the wellhead, and the artificial controllable seismic source is used to excite on the ground or in the well to collect the seismic wave field data in the well.

[0051] 2) The collected data obtained in step 1) is used to obtain high-precision first arrival time information using the maximum energy method first arrival picking method.

[0052] 3) Use median filtering or mean filtering to remove the upgoing waves and eliminate the interference effect of the upgoing waves.

[0053] 4) Take a short time window downward from the first arrival time to extract the first arrival amplitude A i , i is the corresponding channel number. Here the time window length is 30ms, and the amplitude is the root mean square amplitude.

[0054] 5) The amplitude A obtained by statistics i Perform spherical diffusion compensation to eliminate the influence of amplitude change caused by spherical diffusion. The relative wave impedance I is obtained by taking the inverse calculation. r .

[0055] 6) Calculate the wave impedance Imp of the corresponding well section through the existing logging data and compare it with the calculated relative wave impedance I r Make a cross plot and get the correction coefficients a and b by fitting. Here a is the slope of the linear correction and b is the intercept of the linear correction.

[0056] 7) After linear correction of the statistical first arrival amplitude Ai, the inversion wave impedance I is obtained DAS The correction formula is as follows: DAS =a×I r +b.

[0057] 8) To increase the accuracy of the inversion results, the above steps can be repeated, and the inversion wave impedance I obtained each time can be DAS Perform arithmetic averaging or take the median as the final inversion wave impedance.

[0058] Through the above implementation methods, the multi-solution problem of wave impedance inversion using seismic profiles can be effectively overcome, the accuracy and resolution of wave impedance can be significantly improved, and a guarantee can be provided for subsequent reservoir interpretation.

[0059] Based on the same inventive concept, an embodiment of the present invention further provides a device for inverting formation wave impedance using seismic data in a DAS well. Figure 5The following is a schematic diagram showing the implementation steps of a device for inverting formation wave impedance using DAS well seismic data according to an embodiment of the present application. Figure 5 As shown, the device includes: an amplitude acquisition module, which is used to obtain the first arrival amplitude in a time window after the first arrival time of the seismic wave field data in the well; an impedance mapping module, which is used to map the first arrival amplitude into a relative wave impedance; and an impedance correction module, which is used to correct the relative wave impedance to obtain an inversion wave impedance.

[0060] In some optional embodiments, the device also includes: for multiple times collected in-well seismic wave field data or different time window lengths of the same in-well seismic wave field data, the following steps can be repeated multiple times to obtain corresponding multiple inversion wave impedances: obtaining the first arrival amplitude in the time window after the first arrival time of the in-well seismic wave field data; mapping the obtained first arrival amplitude to the corresponding relative wave impedance; correcting the relative wave impedance to obtain the corresponding inversion wave impedance, and obtaining the final inversion wave impedance through a statistical method for the obtained multiple inversion wave impedances.

[0061] In some optional embodiments, obtaining the first arrival amplitude in a time window after the first arrival time includes: obtaining the seismic wave field data in the well excited by the earthquake source; determining the first arrival time using the first arrival picking method; and extracting the first arrival amplitude in a time window backward from the first arrival time.

[0062] In some optional embodiments, before determining the first arrival time by using the first arrival picking method, the device further comprises: using a multi-channel velocity filtering algorithm to remove upgoing waves in the seismic wave field data in the well.

[0063] In some optional embodiments, the device further comprises: performing spherical diffusion compensation on the first-arrival amplitude before mapping the first-arrival amplitude to relative wave impedance.

[0064] In some optional implementations, the relative wave impedance is corrected to obtain the inverse wave impedance, comprising: DAS =a×I r +b; where I DAS is the inverse wave impedance, I r is the relative wave impedance, and the correction coefficients a and b are preset parameters.

[0065] In some optional embodiments, the correction coefficients a and b are determined by the following steps: calculating the wave impedance of the corresponding well section through existing logging data, and making a cross-plot of the wave impedance and the calculated relative wave impedance; and obtaining the correction coefficients a and b through linear fitting.

[0066] Those skilled in the art will understand that Figure 5The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0067] The specific definition of each implementation step in the above-mentioned device for inverting formation wave impedance using DAS well seismic data can be referred to the definition of the method for inverting formation wave impedance using DAS well seismic data above, and will not be repeated here. Its beneficial effects can also be inferred based on the applicability of the above-mentioned method for inverting formation wave impedance using DAS well seismic data.

[0068] An embodiment of the present application provides a device, which includes a processor, a memory, and a program stored in the memory and executable on the processor. When the processor executes the program, the steps of a method for inverting formation wave impedance using seismic data in a DAS well are implemented.

[0069] The present application also provides a computer program product, which, when executed on a data processing device, is suitable for executing a program that initializes the steps of the method for inverting formation wave impedance using seismic data in a DAS well.

[0070] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.

[0071] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0072] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0073] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0074] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0075] The memory may include non-permanent memory in a computer-readable medium, random access memory (RAM) and / or non-volatile memory in the form of read-only memory (ROM) or flash RAM. The memory is an example of a computer-readable medium.

[0076] Computer readable media include permanent and non-permanent, removable and non-removable media, and can be implemented by any method or technology to store information. Information can be computer readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, compact disk read-only memory (CD-ROM), digital versatile disk (DVD) or other optical storage, magnetic cassettes, magnetic tape magnetic disk storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device. As defined herein, computer readable media does not include temporary computer readable media (transitory media), such as modulated data signals and carrier waves.

[0077] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0078] The above are only embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included within the scope of the claims of the present application.

Claims

1. A method for inverting formation wave impedance using DAS well seismic data, characterized in that: The method comprises: A multi-channel velocity filtering algorithm is used to remove upgoing waves from the seismic wave field data in the well; Obtaining the first arrival amplitude in a time window after the first arrival time of the seismic wave field data in the well; the seismic wave field data in the well comes from a fiber optic acoustic wave sensing acquisition instrument; Performing spherical diffusion compensation on the first arrival amplitude; Mapping the first arrival amplitude into a relative wave impedance; After correcting the relative wave impedance, the inverse wave impedance is obtained, including: DAS =a×I r +b; Among them, I DAS is the inverse wave impedance, I r is the relative wave impedance, a and b are the correction coefficients.

2. The method according to claim 1, characterized in that The method further comprises: for multiple acquisitions of well seismic wave field data or different time window lengths of the same well seismic wave field data, the following steps may be repeated multiple times to obtain multiple corresponding inversion wave impedances: obtaining the first arrival amplitude in the time window after the first arrival time of the well seismic wave field data; mapping the obtained first arrival amplitude to the corresponding relative wave impedance; and correcting the relative wave impedance to obtain the corresponding inversion wave impedance; The final inversion wave impedance is obtained by using a statistical method for the obtained multiple inversion wave impedances.

3. The method according to claim 1, characterized in that Obtain the first arrival amplitude in the time window after the first arrival time of the seismic wave field data in the well, including: Acquire the seismic wave field data in the well excited by the earthquake source; Processing the seismic wave field data in the well, and determining the first arrival time by using a first arrival picking method; The first arrival amplitude is extracted by taking a time window backward from the first arrival time.

4. The method according to claim 3, characterized in that: The method of obtaining the seismic wave field data in the well excited by the seismic source comprises: using a fiber optic acoustic wave sensor acquisition instrument, laying an optical cable outside the casing in the well for receiving, using an explosive seismic source or an artificial controllable seismic source to excite on the ground or in the well, and acquiring the seismic wave field data in the well.

5. The method according to claim 1, characterized in that The correction coefficients a and b are determined by the following steps: Calculate the wave impedance of the corresponding well section through the existing logging data; Making a cross plot of the wave impedance and the calculated relative wave impedance; The correction coefficients a and b are obtained by linear fitting.

6. A device for inverting formation wave impedance using DAS well seismic data, characterized in that: The device comprises: An upgoing wave filtering module is used to remove upgoing waves from the seismic wave field data in the well using a multi-channel velocity filtering algorithm; An amplitude acquisition module is used to acquire the first arrival amplitude of the seismic wave field data in the well in a time window after the first arrival time; the seismic wave field data in the well comes from the optical fiber acoustic wave sensor acquisition instrument; A compensation processing module, used for performing spherical diffusion compensation on the first arrival amplitude; An impedance mapping module, used for mapping the first arrival amplitude into a relative wave impedance; An impedance correction module, used to correct the relative wave impedance to obtain an inverse wave impedance, comprising: DAS =a×I r +b; where I DAS is the inverse wave impedance, I r is the relative wave impedance, a and b are the correction coefficients.

7. A device for inverting formation wave impedance using DAS well seismic data, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the method for inverting formation wave impedance using DAS well seismic data according to any one of claims 1 to 5 is implemented.

8. A computer-readable storage medium, characterized in that: The storage medium stores instructions, which, when executed on a computer, enable the computer to execute the method of inverting formation wave impedance using seismic data in a DAS well as described in any one of claims 1 to 5.

Images