Ocean drilling well periphery sound velocity imaging method and device based on multi-scale chromatography

Abstract

The invention relates to the technical field of ocean geophysical exploration, and particularly provides an ocean drilling well periphery sound velocity imaging method and device based on multi-scale chromatography, and the method comprises the steps: obtaining acoustic logging information and a well diameter curve; performing speed extraction or slowness extraction on the acoustic logging information, and constructing a well circumference speed model as an initial inversion model in combination with the well diameter curve; carrying out travel time extraction on the acoustic logging information; and performing inversion on the initial inversion model by using a multi-scale tomography method to obtain a well circumference velocity imaging profile. According to the method, the multi-scale tomography method is applied to ocean drilling well circumference speed imaging for the first time, speed disturbance is subjected to rapid inversion through the background speed and the path length, well circumference small-scale speed rapid imaging is achieved, the situation that in a traditional imaging method, the resolution ratio between a sound source and a receiver is low is overcome, and the imaging accuracy is improved. The imaging precision is effectively improved, and a new thought is provided for optimizing the logging technology, improving underground imaging and the like.

Description

Technical Field

[0001] The present application relates to the field of marine geophysical exploration technology, and in particular to a method and device for ocean drilling well perimeter sonic velocity imaging based on multi-scale tomography. Background Art

[0002] Wellbore velocity imaging is one of the important technologies in the fields of oil and gas exploration, underground engineering, geological survey, etc. In oil and gas exploration, wellbore velocity imaging is used to infer the velocity structure of underground strata and help study the distribution characteristics of underground media, thereby providing reliable reference information for drilling, reservoir evaluation and the formulation of oil production plans. The wellbore velocity field reflects the physical properties of the strata and is one of the important parameters of seismic exploration and downhole measurement. Therefore, accurate wellbore velocity imaging can greatly improve the efficiency of underground resource exploration and development.

[0003] Traditional wellbore velocity imaging methods (such as single-scale tomography) often rely on a specified scale and have difficulty in striking a balance between large and small scales. At the same time, in complex geological conditions such as faults or abnormal media, traditional imaging methods may have difficulty effectively distinguishing different velocity structures. In high-resolution imaging, traditional imaging methods have high computational complexity and data processing difficulty, and often require high computing resources.

[0004] At the same time, offshore drilling is expensive. In the existing technology, complex inversion is required to convert travel time disturbances into velocity disturbances, which requires high computing resources, prolongs the computing time, and increases drilling costs. In summary, it is urgent to provide a fast and accurate ocean drilling well perimeter sonic imaging method, device and equipment to evaluate wellbore stability, formation stress and optimize oil and gas production. Summary of the invention

[0005] In view of the problems existing in the prior art, the present application provides a method and device for imaging the acoustic velocity of the wellbore in ocean drilling based on multi-scale tomography, and combines the multi-scale tomography method to perform wellbore velocity imaging. The multi-scale tomography method is known for its stability and high precision in complex geophysical structures, but it is currently mainly used in ground seismic research. The present invention innovatively applies the multi-scale tomography method to the environment around ocean drilling wells. By combining numerical analysis, the effectiveness of this method in imaging inversion is explored, providing valuable reference value for wellbore imaging.

[0006] In a first aspect, the present application provides a method for imaging the acoustic velocity of ocean drilling wells based on multi-scale tomography, comprising: Obtain sonic logging data and wellbore curves; Extracting velocity or slowness from the acoustic logging data, and building a wellbore velocity model in combination with the wellbore curve as an initial inversion model; Extracting travel time from the sonic logging data; The initial inversion model is inverted using a multi-scale tomography method to obtain a wellbore velocity imaging section.

[0007] In a possible implementation, the acoustic logging data includes a slowness curve and a travel time curve.

[0008] In a possible implementation, the inversion of the initial inversion model using a multi-scale tomography method to obtain a wellbore velocity imaging profile includes: Decomposing the initial inversion model into a plurality of sub-models of different scales; Invert multiple sub-models of different scales simultaneously; The inversion results of all sub-models are superimposed to obtain the wellbore velocity imaging profile.

[0009] In one possible implementation, the calculation formula for inverting multiple sub-models of different scales is: , in, Indicates k The velocity perturbation of the sub-model at each scale; Indicates k The background velocity of the sub-model at each scale; Indicates k The ray path length of the sub-model at each scale; J Indicates k The total number of grids in the sub-model of each scale; Indicates k The sub-model of the scale j The first arrival time in the grid; Indicates k The sub-model of the scale j The theory in the grid arrives.

[0010] In one possible implementation, k The ray path length of the submodel at each scale The calculation formula is: , in, J Indicates k The total number of grids in the sub-model of each scale; I Indicates k In the sub-model of the scale j The total number of sound rays in a grid; Indicates k In the sub-model of the scale j In the gridi The path length of a sound wave ray.

[0011] In a possible implementation, the calculation formula for superimposing the inversion results of all sub-models is: , in, represents the velocity disturbance; K Indicates the total number of sub-models; represents the weighting factor; Indicates k The velocity perturbation of the sub-model at each scale.

[0012] In one possible implementation, the weighting factor The calculation formula is: , in, K Indicates the total number of submodels.

[0013] In a second aspect, the present application provides an ocean drilling well perimeter sonic velocity imaging device based on multi-scale tomography, comprising: Well logging data acquisition module, used to obtain acoustic well logging data and well diameter curve; A model building module, used for extracting velocity or slowness from the acoustic logging data, and building a wellbore velocity model in combination with the wellbore curve as an initial inversion model; A travel time extraction module, used for extracting travel time from the acoustic logging data; An inversion module, used to invert the initial inversion model using a multi-scale tomography method to obtain a wellbore velocity imaging profile; The inversion module comprises: A model decomposition module, used for decomposing the initial inversion model into a plurality of sub-models of different scales; Sub-model inversion module, used to invert multiple sub-models of different scales simultaneously; The inversion stacking module is used to stack the inversion results of all sub-models to obtain the wellbore velocity imaging profile.

[0014] In a third aspect, an embodiment of the present application provides an electronic device, including: processor; Memory; And a computer program, wherein the computer program is stored in the memory, and the computer program includes instructions, and when the instructions are executed by the processor, the electronic device executes any one of the methods described in the first aspect.

[0015] In a fourth aspect, an embodiment of the present application provides a computer-readable storage medium, wherein the computer-readable storage medium includes a stored program, wherein when the program is running, the device where the computer-readable storage medium is located is controlled to execute any one of the methods described in the first aspect.

[0016] Based on the above invention content, compared with the prior art, the present invention applies the multi-scale tomography method to the imaging of sound velocity around ocean drilling wells for the first time, uses the background velocity and path length to quickly invert the velocity disturbance, and realizes the rapid imaging of small-scale velocity anomalies around the well (such as perforations, cracks, fluid pockets, and cement bonding defects outside the casing), which overcomes the low resolution between the sound source and the receiver in traditional imaging methods. It does not require complex inversion, direct calculation, high real-time performance, and effectively improves the imaging accuracy, providing a new idea for optimizing logging technology and improving underground imaging. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0018] Figure 1 A schematic diagram of a flow chart of a method for imaging the perimeter sound velocity of an ocean drilling well based on multi-scale tomography provided in an embodiment of the present application; Figure 2 This is a diagram showing the effect of processing and interpreting the field logging data of the perforated wellbore using the ocean drilling well perimeter sound velocity imaging method based on multi-scale tomography provided in an embodiment of the present application; Figure 3 A structural block diagram of a multi-scale tomography-based ocean drilling well perimeter sound velocity imaging device provided in an embodiment of the present application; Figure 4 A schematic diagram of the structure of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0019] In order to better understand the technical solution of the present application, the embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0020] It should be clear that the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0021] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a", "said" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0022] It should be understood that the term "and / or" used in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0023] In view of the defects of low accuracy and slow speed of existing wellbore velocity imaging methods, the present invention proposes a method and device for ocean drilling wellbore sonic velocity imaging based on multi-scale tomography, and analyzes the velocity profile before and after perforation as an example to prove the reliability of the method. Borehole diameter information can be obtained through other logging methods, which provides constraints on the wellbore conditions during the sonic velocity inversion process, so that the inversion process focuses mainly on the velocity imaging outside the wellbore. Numerical simulation and field experimental results show that the ocean drilling wellbore sonic velocity imaging method based on multi-scale tomography disclosed in the present invention has high accuracy in matching penetration depth, and has application potential in the fields of unconventional oil and gas, hydrogen, geothermal energy development and carbon dioxide storage.

[0024] See also Figure 1 , is a flow chart of a method for imaging the perimeter sound velocity of an ocean drilling well based on multi-scale tomography provided in an embodiment of the present application. Figure 1 As shown, it mainly includes the following steps.

[0025] Step S1, obtaining acoustic logging data and wellbore curves.

[0026] The acoustic logging data include slowness curves, travel time curves, etc.

[0027] The travel time curve is obtained by using the shortest path method of Fermat's principle.

[0028] Step S2, extracting velocity or slowness from the acoustic logging data, and building a wellbore velocity model in combination with the wellbore curve as an initial inversion model.

[0029] Step S3, extracting travel time from the acoustic logging data.

[0030] Step S4, invert the initial inversion model using a multi-scale tomography method to obtain a wellbore velocity imaging profile. Specifically: Step S41, decomposing the initial inversion model into a plurality of sub-models of different scales.

[0031] Step S42, inverting multiple sub-models of different scales simultaneously.

[0032] The inversion calculation formula is: , in, Indicates k The velocity perturbation of the sub-model at each scale; Indicates k The background speed of the sub-model of the scale, in the embodiment of the present application From k The average ray velocity of the sub-model of each scale; Indicates k The ray path length of the sub-model at each scale; J Indicates k The total number of grids in the sub-model of each scale; Indicates k The sub-model of the scale j The first arrival time in the grid is Indicates k The sub-model of the scale j The theoretical arrival time in the grid. This application is to pass the background speed With path length Combined with the inversion of velocity disturbance, rapid imaging of small-scale velocity anomalies around the well (such as perforations, cracks, fluid pockets, and cement bonding defects outside the casing) can be achieved without complex inversion, direct calculation, and high real-time performance.

[0033] No. k The ray path length of the submodel at each scale The calculation formula is: , in, J Indicates k The total number of grids in the sub-model of each scale; I Indicates k In the sub-model of the scale j The total number of sound rays in a grid; Indicates k In the sub-model of the scale j In the grid i The path length of a sound wave ray.

[0034] Step S23, superimposing the inversion results of all sub-models to obtain a wellbore velocity imaging profile.

[0035] The calculation formula for superimposing the inversion results of all sub-models is: , in, represents the velocity disturbance; K Indicates the total number of sub-models; represents the weighting factor; Indicates k The velocity perturbation of the sub-model at each scale.

[0036] Weighting Factor The calculation formula is: , in, K Indicates the total number of submodels.

[0037] Taking the field logging data of the perforated wellbore as an example, the method disclosed in the embodiment of the present application is used to perform wellbore perimeter acoustic velocity imaging to prove the reliability of the method described in the present application.

[0038] See also Figure 2 , which is a diagram showing the effect of processing and interpreting the field logging data of the perforated wellbore using the ocean drilling well peripheral sound velocity imaging method based on multi-scale tomography provided in an embodiment of the present application. Figure 2 The figure shows the logging data of a perforated wellbore with a depth of 20 meters, and the perforation depth varies from X148.5 to X158.5 (10 meters). Panels 1 and 2 show the gamma ray (GR) and slowness curves before and after perforation, respectively. The slowness curves before and after perforation in Panel 2 are almost overlapped, the slowness curve before perforation is black, and the slowness curve after perforation is red, which indicates that the perforation effect is mainly limited to the vicinity of the wellbore, and the change in far-field properties is small. Panel 3 shows the P-wave travel time curve using 8 receivers, from which it can be seen that there is a significant delay after perforation of the target layer.

[0039] The acoustic logging data before and after perforation are used as the initial inversion model, and the initial inversion model includes 385 grids in the depth direction and 131 grids in the radial direction, with grid sizes of 0.0508m and 0.01m, respectively. The ocean drilling well perimeter sonic velocity imaging method based on multi-scale tomography provided in the embodiment of the present application is used for inversion, and the model is divided into 131 sub-models to facilitate fine-scale analysis of velocity changes. Panels 4 and 5 show the velocity profiles before and after perforation, respectively. The standard deviations of the initial inversion model were 18.53µs and 18.32µs, respectively, which were reduced to 1.32µs and 1.63µs, respectively, after iteration. The overall velocity changes are not large, but the velocity changes in specific depth intervals are obvious, which reflects the low-scale changes in the properties of the formation after perforation. Panel 6 shows the velocity changes in specific depth intervals before and after perforation. It can be seen from Panel 6 that the perforation spacing is significantly reduced, especially at X150, X151, X152, X155.8 and X157 meters, among which the impact at X157 meters is the greatest. The estimated penetration depth is about 17 cm, but due to the limited receiver, the actual depth may be greater. This shows the ability of the method proposed in the embodiment of the present application to solve the velocity changes caused by perforation.

[0040] In order to further illustrate the reliability of the processing results of the method proposed in the embodiment of the present application, Panel 7 shows the average time delay before and after perforation (the area on the left side of the dotted line in Panel 7, from left to right) and the perforation penetration depth estimated based on the time delay (the area on the right side of the dotted line in Panel 7, from right to left). It can be seen from Panel 7 that the maximum perforation depth is 19 cm, which is very consistent with the inversion result of the method proposed in the embodiment of the present application, confirming the reliability of the method proposed in the embodiment of the present application. However, it is worth noting that the deviation between the depth estimation area and the actual perforation area is about 1.5 meters, and this deviation is mainly caused by the effect of the size of the transceiver equipment on the time delay. Although the depth deviation is relatively small, it reminds technicians in this field to carefully consider the design parameters of the instrument when evaluating the perforation area.

[0041] Corresponding to the above-mentioned embodiments, the present application also provides an ocean drilling well perimeter sonic velocity imaging device based on multi-scale tomography.

[0042] See also Figure 3 , is a structural block diagram of an ocean drilling well perimeter sonic velocity imaging device based on multi-scale tomography provided in an embodiment of the present application. Figure 3 As shown, it mainly includes the following modules.

[0043] Well logging data acquisition module, used to obtain acoustic well logging data and well diameter curve; A model building module, used for extracting velocity or slowness from the acoustic logging data, and building a wellbore velocity model in combination with the wellbore curve as an initial inversion model; A travel time extraction module, used for extracting travel time from the acoustic logging data; The inversion module is used to invert the initial inversion model using a multi-scale tomography method to obtain a wellbore velocity imaging section.

[0044] The inversion module further comprises: The model decomposition module is used to decompose the initial inversion model into a plurality of sub-models of different scales.

[0045] The sub-model inversion module is used to invert multiple sub-models of different scales simultaneously.

[0046] The inversion stacking module is used to stack the inversion results of all sub-models to obtain the wellbore velocity imaging profile.

[0047] It should be pointed out that the specific contents involved in the embodiments of the present application can be found in the description of the above method embodiments, and for the sake of brevity, they will not be repeated here.

[0048] Corresponding to the above embodiment, an embodiment of the present application further provides an electronic device.

[0049] See also Figure 4 , is a schematic diagram of the structure of an electronic device provided in an embodiment of the present application. Figure 4 As shown, the electronic device 400 may include: a processor 401, a memory 402 and a communication unit 403. These components communicate via one or more buses. Those skilled in the art will appreciate that the electronic device structure shown in the figure does not limit the embodiments of the present application, and it may be a bus structure or a star structure, and may include more or fewer components than shown in the figure, or combine certain components, or arrange components differently.

[0050] The communication unit 403 is used to establish a communication channel so that the electronic device can communicate with other devices.

[0051] The processor 401 is the control center of the electronic device. It uses various interfaces and lines to connect various parts of the entire electronic device. It runs or executes software programs and / or modules stored in the memory 402, and calls data stored in the memory to perform various functions of the electronic device and / or process data. The processor can be composed of an integrated circuit (IC), for example, it can be composed of a single packaged IC, or it can be composed of multiple packaged ICs with the same or different functions. For example, the processor 401 can include only a central processing unit (CPU). In the embodiment of the present application, the CPU can be a single computing core or multiple computing cores.

[0052] The memory 402 is used to store the execution instructions of the processor 401. The memory 402 can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic memory, flash memory, magnetic disk or optical disk.

[0053] When the execution instructions in the memory 402 are executed by the processor 401 , the electronic device 400 is enabled to execute part or all of the steps in the above method embodiment.

[0054] Corresponding to the above embodiment, the embodiment of the present application further provides a computer-readable storage medium, wherein the computer-readable storage medium may store a program, wherein when the program is running, the device where the computer-readable storage medium is located may be controlled to execute some or all of the steps in the above method embodiment. In a specific implementation, the computer-readable storage medium may be a magnetic disk, an optical disk, a read-only memory (ROM) or a random access memory (RAM).

[0055] Corresponding to the above-mentioned embodiment, the embodiment of the present application further provides a computer program product, which includes executable instructions. When the executable instructions are executed on a computer, the computer executes some or all of the steps in the above-mentioned method embodiment.

[0056] In the embodiments of the present application, "at least one" refers to one or more, and "plurality" refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent the existence of A alone, the existence of A and B at the same time, and the existence of B alone. Among them, A and B can be singular or plural. The character " / " generally indicates that the previous and subsequent associated objects are in an "or" relationship. "At least one of the following" and similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b and c can be represented by: a, b, c, ab, ac, bc, or abc, where a, b, c can be single or multiple.

[0057] Those of ordinary skill in the art will appreciate that the various units and algorithm steps described in the embodiments disclosed herein can be implemented in a combination of electronic hardware, computer software, and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0058] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0059] In several embodiments provided in the present application, if any function is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application is essentially or the part that contributes to the prior art or the part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM), random access memory (RAM), disk or optical disk, etc., various media that can store program codes.

[0060] The above is only a specific implementation of the present application. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. The protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A method for imaging the acoustic velocity of ocean drilling wells based on multi-scale tomography, characterized in that: include: Obtain sonic logging data and wellbore curves; Extracting velocity or slowness from the acoustic logging data, and building a wellbore velocity model in combination with the wellbore curve as an initial inversion model; Extracting travel time from the sonic logging data; The initial inversion model is inverted using a multi-scale tomography method to obtain a wellbore velocity imaging section.

2. The method for imaging the acoustic velocity of ocean drilling wells based on multi-scale tomography according to claim 1, characterized in that: The sonic logging data include a slowness curve and a travel time curve.

3. The method for imaging the acoustic velocity of ocean drilling wells based on multi-scale tomography according to claim 1, characterized in that: The method of inverting the initial inversion model by using a multi-scale tomography method to obtain a wellbore velocity imaging profile includes: Decomposing the initial inversion model into a plurality of sub-models of different scales; Invert multiple sub-models of different scales simultaneously; The inversion results of all sub-models are superimposed to obtain the wellbore velocity imaging profile.

4. The method for imaging the acoustic velocity of ocean drilling wells based on multi-scale tomography according to claim 3, characterized in that: The calculation formula for inversion of multiple sub-models of different scales is: ， in, Indicates k The velocity perturbation of the sub-model at each scale; Indicates k The background velocity of the sub-model at each scale; Indicates k The ray path length of the sub-model at each scale; J Indicates k The total number of grids in the sub-model of each scale; Indicates k The sub-model of the scale j The first arrival time in the grid; Indicates k The sub-model of the scale j The theory in the grid arrives.

5. The method for imaging the acoustic velocity of ocean drilling wells based on multi-scale tomography according to claim 4, characterized in that: No. k The ray path length of the sub-model at each scale The calculation formula is: ， in, J Indicates k The total number of grids in the sub-model of each scale; I Indicates k In the sub-model of the scale j The total number of sound rays in a grid; Indicates k In the sub-model of the scale j In the grid i The path length of a sound wave ray.

6. The method for imaging the acoustic velocity of ocean drilling wells based on multi-scale tomography according to claim 3, characterized in that: The calculation formula for superimposing the inversion results of all sub-models is: ， in, represents the velocity disturbance; K Indicates the total number of sub-models; represents the weighting factor; Indicates k The velocity perturbation of the sub-model at each scale.

7. The method for imaging the acoustic velocity of ocean drilling wells based on multi-scale tomography according to claim 6, characterized in that: Weighting Factor The calculation formula is: ， in, K Indicates the total number of submodels.

8. An ocean drilling well perimeter sonic velocity imaging device based on multi-scale tomography, characterized in that: include: Well logging data acquisition module, used to obtain acoustic well logging data and well diameter curve; A model building module, used for extracting velocity or slowness from the acoustic logging data, and building a wellbore velocity model in combination with the wellbore curve as an initial inversion model; A travel time extraction module, used for extracting travel time from the acoustic logging data; An inversion module, used to invert the initial inversion model using a multi-scale tomography method to obtain a wellbore velocity imaging profile; The inversion module comprises: A model decomposition module, used for decomposing the initial inversion model into a plurality of sub-models of different scales; Sub-model inversion module, used to invert multiple sub-models of different scales simultaneously; The inversion stacking module is used to stack the inversion results of all sub-models to obtain the wellbore velocity imaging profile.

9. An electronic device, characterized in that: include: processor; Memory; And a computer program, wherein the computer program is stored in the memory, and the computer program includes instructions, and when the instructions are executed by the processor, the electronic device executes the method according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium includes a stored program, wherein when the program is executed, the device where the computer-readable storage medium is located is controlled to execute the method according to any one of claims 1 to 7.

Images