Numerical simulation method of three-dimensional borehole acoustic field based on Fork-Join parallel mode

Abstract

The present invention provides a three-dimensional borehole acoustic field numerical simulation method based on the Fork-Join parallel mode, comprising: establishing a three-dimensional formation model according to simulated formation geometry, geological parameter information and borehole measurement environment, combined with dispersion conditions and stability conditions; dividing the three-dimensional formation model into a plurality of sub-regions based on the Fork-Join parallel principle, and calculating the acoustic field in each sub-region simultaneously by using multi-core multi-threading; combining the acoustic fields in each sub-region to obtain the acoustic field of the entire three-dimensional formation model region; using a multi-unit receiver to record the acoustic field at a specified position in the three-dimensional formation model at different times, and obtaining the acoustic field excited by a specific sound source in the well in the wellbore and the formation, wherein, based on the Fork-Join parallel mode, a three-dimensional borehole acoustic field numerical simulation technology suitable for Java language is proposed, which is simple and easy to implement, can effectively utilize the multi-core advantage of a computer, and improve the program running efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of oil and gas exploration, and in particular to a three-dimensional wellbore acoustic field numerical simulation method and device based on a Fork-Join parallel mode. Background Art

[0002] The numerical simulation of borehole acoustic field is an effective tool for the design, development and manufacture of petroleum logging instruments. It is of great significance in optimizing the structure of acoustic logging instruments and understanding the propagation law of waves in complex media. At the same time, it can provide guidance and means for the processing and application of acoustic logging data, and is an important basis for the quantitative analysis of acoustic logging. The numerical simulation methods of borehole acoustic field in complex media mainly include finite difference method, finite element method, pseudo-spectral method, spectral element method, etc. In comparison, the finite difference method has small calculation amount, simple implementation and low memory requirement, and is the most widely used in practice. At present, the finite difference numerical simulation of three-dimensional borehole acoustic field generally adopts parallel computing frameworks such as OpenMP, MPI, and CUDA to improve the running efficiency of the program. However, the above frameworks are difficult to be effectively applied to the parallel transformation of Java serial code. Summary of the invention

[0003] In view of the problems in the prior art, the present invention provides a three-dimensional borehole acoustic field numerical simulation method and device based on the Fork-Join parallel mode, an electronic device and a computer-readable storage medium, which can at least partially solve the problems in the prior art.

[0004] In order to achieve the above object, the present invention adopts the following technical solution:

[0005] In a first aspect, a method for numerically simulating a three-dimensional borehole acoustic field based on a Fork-Join parallel mode is provided, comprising:

[0006] According to the simulated formation geometry, geological parameter information and wellbore measurement environment, a three-dimensional formation model is established in combination with dispersion conditions and stability conditions;

[0007] Based on the Fork-Join parallel principle, the 3D stratigraphic model is divided into multiple sub-areas, and the acoustic field in each sub-area is calculated simultaneously using multi-core and multi-threading.

[0008] The sound fields in each sub-area are combined to obtain the sound field of the entire three-dimensional stratum model area;

[0009] The acoustic field at the designated position in the three-dimensional formation model at different times is recorded by using multi-unit receivers to obtain the acoustic field excited by the specific sound source in the wellbore and formation.

[0010] Furthermore, the calculation of the sound field in each sub-area includes:

[0011] The staggered grid discretization, high-order difference approximation and complex frequency shift perfectly matched layer suppression model boundary reflection are adopted to realize the finite difference calculation of the sound field in each sub-area.

[0012] Furthermore, the staggered grid discretization, high-order difference approximation and complex frequency shift perfectly matched layer suppression model boundary reflection are used to realize the finite difference calculation of the sound field in each sub-area, including:

[0013] Discretize the sub-regions by staggered grids to obtain the corresponding grid model;

[0014] The elastic wave equation in isotropic medium is expressed in first-order stress-velocity form, and the elastic wave equation in first-order stress-velocity form is approximated by high-order difference.

[0015] The velocity component and stress component in the grid model are calculated using the approximated equations, and the calculation results are iterated to obtain the wave field at any time in the sub-area;

[0016] Calculate the attenuation term of the wave equation in the perfectly matched layer region of the sub-region, and subtract the attenuation term from the wave field at any time in the sub-region to obtain the final wave field in the sub-region;

[0017] If the sub-region does not contain a perfectly matched layer region, the corresponding attenuation term is 0.

[0018] Furthermore, the three-dimensional stratigraphic model is divided into multiple sub-areas, including:

[0019] A threshold value is obtained according to the calculation scale of the acoustic field in the three-dimensional stratum model area and the number of cores of the computer processor;

[0020] The three-dimensional stratum model is recursively divided into a plurality of sub-areas according to the threshold.

[0021] In a second aspect, a three-dimensional borehole acoustic field numerical simulation device based on a Fork-Join parallel mode is provided, comprising:

[0022] Modeling module, which establishes a three-dimensional formation model based on simulated formation geometry, geological parameter information and wellbore measurement environment, combined with dispersion conditions and stability conditions;

[0023] The parallel acoustic field calculation module divides the 3D stratigraphic model into multiple sub-areas based on the Fork-Join parallel principle, and uses multi-core and multi-threading to simultaneously calculate the acoustic field in each sub-area.

[0024] The sound field combination module combines the sound fields in each sub-area to obtain the sound field of the entire three-dimensional stratum model area;

[0025] The acoustic field result output module uses a multi-unit receiver to record the acoustic field at a specified position in the three-dimensional formation model at different times, and obtains the acoustic field excited by a specific sound source in the wellbore and formation.

[0026] Furthermore, the parallel sound field calculation module includes:

[0027] The finite difference calculation unit adopts staggered grid discretization, high-order difference approximation and complex frequency shift perfectly matched layer suppression model boundary reflection to realize the finite difference calculation of the sound field in each sub-area.

[0028] Furthermore, the finite difference calculation unit includes:

[0029] Staggered grid discretization sub-units, staggered grid discretization of sub-regions to obtain the corresponding grid model;

[0030] The equation approximation subunit expresses the elastic wave equation in isotropic media in the first-order stress-velocity form and approximates the elastic wave equation in the first-order stress-velocity form by using high-order differences;

[0031] The wave field preliminary calculation subunit calculates the velocity component and stress component in the grid model using the approximated equations, and iterates the calculation results to obtain the wave field at any time in the sub-area;

[0032] The wave field attenuation subunit calculates the attenuation term of the wave equation in the perfectly matched layer region of the sub-region, and subtracts the attenuation term from the wave field at any time in the sub-region to obtain the final wave field in the sub-region;

[0033] If the sub-region does not contain a perfectly matched layer region, the corresponding attenuation term is 0.

[0034] Furthermore, the parallel sound field calculation module includes:

[0035] A threshold value acquisition unit obtains a threshold value according to the calculation scale of the acoustic field in the three-dimensional stratum model area and the number of cores of the computer processor;

[0036] The region division unit divides the three-dimensional stratigraphic model into a plurality of sub-regions in a recursive manner according to the threshold value.

[0037] In a third aspect, an electronic device is provided, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the steps of the above-mentioned method for numerical simulation of three-dimensional borehole acoustic field based on Fork-Join parallel mode are implemented.

[0038] In a fourth aspect, a computer-readable storage medium is provided, on which a computer program is stored, and when the computer program is executed by a processor, the steps of the above-mentioned three-dimensional borehole acoustic field numerical simulation method based on the Fork-Join parallel mode are implemented.

[0039] The invention provides a three-dimensional borehole acoustic field numerical simulation method based on the Fork-Join parallel mode, comprising: establishing a three-dimensional formation model according to simulated formation geometry, geological parameter information and borehole measurement environment, combined with dispersion conditions and stability conditions; dividing the three-dimensional formation model into a plurality of sub-regions based on the Fork-Join parallel principle, and calculating the acoustic field in each sub-region simultaneously by using multi-core multi-threading; combining the acoustic fields in each sub-region to obtain the acoustic field of the entire three-dimensional formation model region; and using a multi-unit receiver to record the acoustic field at a specified position in the three-dimensional formation model at different times, so as to obtain the acoustic field excited by a specific sound source in the well in the wellbore and the formation. Based on the Fork-Join parallel mode, a three-dimensional borehole acoustic field numerical simulation technology suitable for Java language is proposed, which is simple and easy to implement, can effectively utilize the advantages of computer multi-cores, improve program operation efficiency, and provide a powerful tool for three-dimensional borehole acoustic field elastic wave numerical simulation.

[0040] In addition, for the numerical simulation problem of three-dimensional borehole acoustic field in Java language, staggered grid discretization, high-order difference approximation and complex frequency shift perfectly matched layer suppression model boundary reflection are adopted to realize the accurate simulation of three-dimensional elastic wave equation in rectangular coordinate system.

[0041] In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are specifically cited below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the prior art descriptions. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. In the drawings:

[0043] Figure 1 is a schematic diagram of the architecture between the server S1 and the client device B1 in an embodiment of the present invention;

[0044] Figure 2 Schematic diagram of the process of the three-dimensional borehole acoustic field numerical simulation method based on the Fork-Join parallel mode in the embodiment of the present invention Figure 1 ;

[0045] Figure 3The specific steps of implementing the finite difference calculation of the sound field in each sub-region by using staggered grid discretization, high-order difference approximation and complex frequency shift perfectly matched layer suppression model boundary reflection in the embodiment of the present invention are shown;

[0046] Figure 4 The specific steps of dividing the three-dimensional stratum model into multiple sub-areas in the embodiment of the present invention are shown;

[0047] Figure 5 The wellbore acoustic field on the XOZ section at different times of the dipole acoustic source in the well in the embodiment of the present invention is shown;

[0048] Figure 6 A schematic diagram of a staggered grid in an embodiment of the present invention is shown;

[0049] Figure 7 The Fork-Join parallel mode execution principle in the embodiment of the present invention is shown;

[0050] Figure 8 The finite difference parallel computing framework based on the Fork-Join parallel mode in the embodiment of the present invention is shown;

[0051] Fig. 9 It is a structural block diagram of a three-dimensional wellbore acoustic field numerical simulation device based on the Fork-Join parallel mode in an embodiment of the present invention;

[0052] Fig.10 4 is a structural diagram of an electronic device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0053] In order to enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of this application.

[0054] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0055] It should be noted that the terms "including" and "having" and any variations thereof in the specification and claims of the present application and the above-mentioned drawings are intended to cover non-exclusive inclusions. For example, a process, method, system, product or apparatus comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or apparatuses.

[0056] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0057] The existing finite difference numerical simulation framework of three-dimensional borehole acoustic field is difficult to be effectively applied to the parallel transformation of Java serial code.

[0058] In the embodiment of the present invention, based on the Fork-Join parallel mode, a three-dimensional borehole acoustic field numerical simulation technology suitable for Java language is proposed. The technology is simple and easy to implement, can effectively utilize the advantages of computer multi-core, improve program operation efficiency, and provide a powerful tool for the three-dimensional borehole acoustic field elastic wave numerical simulation.

[0059] In view of this, the present application provides a three-dimensional borehole acoustic field numerical simulation device based on the Fork-Join parallel mode, which can be a server S1, see Figure 1 , the server S1 can be connected to at least one client device B1 in communication, the client device B1 can send the simulated formation geometry, geological parameter information and borehole measurement environment to the server S1, and the server S1 can receive the simulated formation geometry, geological parameter information and borehole measurement environment online. The server S1 can pre-process the obtained simulated formation geometry, geological parameter information and borehole measurement environment online or offline, and establish a three-dimensional formation model based on the simulated formation geometry, geological parameter information and borehole measurement environment, combined with dispersion conditions and stability conditions; based on the Fork-Join parallel principle, the three-dimensional formation model is divided into multiple sub-areas, and the sound field in each sub-area is calculated simultaneously using multi-core multi-threading; the sound field in each sub-area is combined to obtain the sound field of the entire three-dimensional formation model area; the sound field at a specified position in the three-dimensional formation model at different times is recorded using a multi-unit receiver to obtain the sound field excited by a specific sound source in the wellbore and the formation. Then, the server S1 can send the sound field online to the client device B1. The client device B1 can receive the sound field online.

[0060] Based on the above content, the client device B1 may have a display interface, so that the user can view the sound field sent by the server S1 according to the interface.

[0061] It is understandable that the client device B1 may include a smart phone, a tablet electronic device, a network set-top box, a portable computer, a desktop computer, a personal digital assistant (PDA), a vehicle-mounted device, a smart wearable device, etc. Among them, the smart wearable device may include smart glasses, a smart watch, a smart bracelet, etc.

[0062] In practical applications, the part of the numerical simulation of the three-dimensional borehole acoustic field based on the Fork-Join parallel mode can be executed on the server S1 side as described above, that is, Figure 1 The architecture shown can also be that all operations are completed in the client device B1, and the client device B1 can be directly connected to the database server S2 for communication. The specific selection can be based on the processing power of the client device B1 and the limitations of the user's usage scenario. This application is not limited to this. If all operations are completed in the client device B1, the client device B1 can also include a processor for performing specific processing of the numerical simulation of the three-dimensional borehole acoustic field based on the Fork-Join parallel mode.

[0063] The server and the client device may communicate using any suitable network protocol, including network protocols that have not yet been developed on the filing date of this application. The network protocol may include, for example, TCP / IP protocol, UDP / IP protocol, HTTP protocol, HTTPS protocol, etc. Of course, the network protocol may also include, for example, RPC protocol (Remote Procedure Call Protocol) and REST protocol (Representational State Transfer) used on top of the above protocols.

[0064] Figure 2 Schematic diagram of the process of the three-dimensional borehole acoustic field numerical simulation method based on the Fork-Join parallel mode in the embodiment of the present invention Figure 1 ;like Figure 2 As shown, the three-dimensional borehole acoustic field numerical simulation method based on the Fork-Join parallel mode may include the following contents:

[0065] Step S100: establishing a three-dimensional formation model according to simulated formation geometry, geological parameter information and wellbore measurement environment, combined with dispersion conditions and stability conditions;

[0066] Among them, dispersion conditions and stability conditions are the basic conditions in the finite difference simulation process of wave equations. The essence of three-dimensional stratigraphic modeling is to divide the space area using cubic grids of specified size, and then assign the attributes of each grid point according to the simulated geological information (set the density of grid points, longitudinal and transverse wave velocities). In the finite difference simulation calculation of wave equations, the wave field at a point in space is calculated according to the attributes of the corresponding grid points.

[0067] For example, let the density of the formation model be ρ and the P-wave velocity be V P , the shear wave velocity is V S The radius of the wellbore is a, and the fluid is filled with a density of ρ. f , the longitudinal wave velocity is V f , the shear wave velocity is 0; the number of grids in the X, Y and Z directions of the model is N respectively x 、N y 、N z , the spatial sampling steps are Δx, Δy, Δz respectively; the time sampling step is Δt. Among them, the spatial sampling step and time sampling step of the model must meet the corresponding dispersion conditions and stability conditions:

[0068]

[0069] In the above formula, v max and v min is the maximum and minimum velocity in the formation model; a m is the differential coefficient used; n is half of the spatial order; f max The highest frequency covered by the sound source.

[0070] Step S200: Based on the Fork-Join parallel principle, the three-dimensional stratum model is divided into a plurality of sub-regions, and the acoustic field in each sub-region is calculated simultaneously by using multi-core multi-threading;

[0071] Among them, the execution principle of the Fork-Join parallel framework is as follows Figure 7 As shown in the figure, the original task Task0 is recursively divided into several different subtasks (Task0-1-1, ..., Task0-NN) according to the threshold size of the subtask scale. The multi-core and multi-threaded computer is used to calculate each subtask at the same time. When a subtask in a thread is completed ahead of schedule, the current thread will automatically "steal" the unfinished task from other threads for calculation instead of being idle and waiting, thereby making full use of the multi-core advantage of the computer to effectively improve the calculation efficiency. When all subtasks are calculated, the results of each subtask are combined to get the final result of the original task.

[0072] Step S300: combining the sound fields in each sub-area to obtain the sound field of the entire three-dimensional stratum model area;

[0073] Among them, the acoustic field at a certain moment is divided into two parts: velocity field and stress field for calculation. When calculating the velocity field and stress field of the entire model area at a certain moment, the order of solving different positions in the space does not affect the final result. Therefore, in the actual calculation process, the entire space area can be divided into several sub-areas according to the threshold of the number of sub-areas grids, such as Figure 8 As shown, by calculating the velocity field and stress field of each sub-area in parallel and then combining the final results, the sound field of the entire space at a certain moment can be obtained.

[0074] Step S400: Using a multi-unit receiver to record the acoustic field at a specified position in the three-dimensional formation model at different times, and obtain the acoustic field excited by a specific sound source in the wellbore and the formation.

[0075] Among them, the sound field output recorded by the multi-unit receiver at different times can be used to obtain the sound field generated by the specific sound source in the wellbore and formation at different times, such as Figure 5 shown.

[0076] The embodiment of the present invention provides a three-dimensional borehole acoustic field numerical simulation method based on the Fork-Join parallel mode. Based on the Fork-Join parallel mode, a three-dimensional borehole acoustic field numerical simulation technology suitable for Java language is proposed. The method is simple and easy to implement, can effectively utilize the advantages of computer multi-core, improve program operation efficiency, and provide a powerful tool for the three-dimensional borehole acoustic field elastic wave numerical simulation.

[0077] In an optional embodiment, calculating the sound field in each sub-region specifically includes: using staggered grid discretization, high-order difference approximation and complex frequency shift perfectly matched layer suppression model boundary reflection to achieve finite difference calculation of the sound field in each sub-region.

[0078] Specifically, see Figure 3 , including the following:

[0079] Step S1: discretize the sub-region into staggered grids to obtain the corresponding grid model;

[0080] Specifically, in the staggered grid discretization process, the stress component and the velocity component are defined on different grids to better couple the stress and velocity, such as Figure 6 As shown. The grid where the solid circle is located in the figure is an integer grid, and the grid where the hollow circle is located is a half grid. The Lame coefficient λ, μ and density ρ of the medium are assigned to the integer grid nodes. The density ρ and Lame coefficient λ at the non-integer grid point are obtained by the arithmetic average of the values ​​of the surrounding grid points, and the Lame coefficient μ at the non-integer grid point is obtained by the harmonic average of the values ​​of the surrounding grid points, as shown in the following formula:

[0081]

[0082] Step S2: Expressing the elastic wave equation in the isotropic medium in a first-order stress-velocity form, and approximating the elastic wave equation in the first-order stress-velocity form by using a high-order difference;

[0083] Specifically, the elastic wave equation in isotropic media is expressed in the form of first-order stress-velocity, as shown below:

[0084]

[0085]

[0086] In the formula, v x 、v y and v z are the vibration velocities of the particle in the X, Y and Z directions respectively; σ xx , σ yy and σ zz are the normal stresses in the X, Y and Z directions respectively; σ xy , σ yz and σ xz is the shear stress; ρ is the medium density; λ and μ are the Lame coefficients of the medium.

[0087] The Lame coefficients λ and μ at the spatial grid points can be obtained from the formation density ρ and the formation P-wave velocity V at the corresponding grid points. P , formation shear wave velocity V S Calculated.

[0088] In addition, the first-order velocity-stress elastic wave equation is approximated by using high-order differences. The approximate format of any 2N-order staggered grid difference can be written as:

[0089]

[0090] In the above formula, the difference coefficient a m It can be obtained by the following formula:

[0091]

[0092] In the present invention, the time difference is selected as the second order, and the space difference is selected as the high order. The differential form of equation 3 and equation 4 can be written as:

[0093]

[0094]

[0095] Step S3: using the approximated equations to calculate the velocity component and the stress component in the grid model, and iterating the calculation results to obtain the wave field at any time in the sub-area;

[0096] Specifically, in the finite difference simulation process, the velocity component of the wave field at a certain moment in the network model is first calculated according to Formula 7, and then the corresponding stress component in the network model is calculated according to Formula 8. Since the difference format in the above formula is explicit, the wave field at any moment in the formation model can be directly obtained by the iterative method.

[0097] Step S4: calculating the attenuation term of the wave equation in the perfectly matched layer region of the sub-region, and subtracting the attenuation term from the wave field at any moment in the sub-region to obtain the final wave field in the sub-region;

[0098] If the sub-region does not include a perfectly matched layer region, the corresponding attenuation term is 0.

[0099] Specifically, a complex frequency shift perfect matching layer is used to attenuate the wave field in the matching layer region, thereby reducing the interference of false reflections on the model boundary. The attenuation factor in the matching layer is shown in the following formula:

[0100]

[0101] In the above formula, L is the thickness of the perfectly matched layer; N d is the binomial order, usually 2; V P is the longitudinal wave velocity of the medium; R is the ideal boundary reflection coefficient; f0 is the main frequency of the sound source; x, y and z are the distances from the grid point in the matching layer to the interface between the matching layer and the main area in the X, Y and Z directions respectively; d x d y and d z are the real attenuation factors in the X, Y and Z directions respectively, d0 is the real attenuation factor at the outermost grid of the matching layer; α x , α y and α z are the complex frequency shift factors in the X, Y and Z directions respectively, α0 is the complex frequency shift factor of the innermost grid of the matching layer; κ x , κ y and κ z are the evanescent wave suppression factors in the X, Y and Z directions respectively, and κ0 is the evanescent wave suppression factor of the outermost grid of the matching layer. Among them, the real attenuation factor d, the complex frequency shift factor α, and the evanescent wave suppression factor κ are all well-known parameters in the complex frequency shift perfect matching layer method.

[0102] When actually calculating the sound field at a certain moment, the initial difference calculation is first performed on the wave equations in the main area and the perfect matching layer area, and then the attenuation term of the wave equation in the perfect matching layer area is calculated. The initial result of the difference calculation in the perfect matching layer area is subtracted from the attenuation term to obtain the wave field in the main area and the perfect matching layer area at that moment.

[0103] In an alternative embodiment, see Figure 4 , the three-dimensional stratigraphic model is divided into multiple sub-areas including:

[0104] Step S10: obtaining a threshold value according to the calculation scale of the acoustic field in the three-dimensional stratum model area and the number of cores of the computer processor;

[0105] Specifically, according to the actual size of the model, set an appropriate sub-region division threshold to divide the entire model area. In order to facilitate sub-region division, the values ​​of the three-dimensional space are stored in a one-dimensional array, and the total number of regional grids N = N x ·N y ·N z , then the sub-region grid number threshold θ can be set as:

[0106]

[0107] Where N is the computing scale of the total task, that is, the total number of regional grids; β is the number of cores of the computer processor, which generally refers to the number of logical cores of the CPU.

[0108] Step S20: Divide the three-dimensional stratum model into a plurality of sub-areas in a recursive manner according to the threshold.

[0109] Among them, the sub-region division method can be set. The present invention adopts a binary division method, that is, when the number of grids in a certain area is greater than the division threshold of the number of grids in the sub-region, it is divided into two equal parts. If the number of grids in the divided area is still greater than the threshold of the number of grids in the sub-region, it is further divided into two equal parts until the final number of grids in the sub-region is less than or equal to the threshold of the number of grids in the sub-region;

[0110] In addition, it is worth mentioning that when calculating, it is necessary to create an algorithm implementation class for the velocity field, named VelocityCalculation. This class needs to inherit the java.util.concurrent.RecursiveAction class and implement the compute() method in the RecursiveAction class. In this method, the specific calculation of the velocity field at a certain moment is completed. In the compute() method, the fork() function in the RecursiveAction class is first called to divide the entire model area into sub-areas according to the above-mentioned binary method, and then different CPU processor cores are used to simultaneously calculate the velocity field in each sub-area according to the above-mentioned method. After the velocity field in each sub-area is calculated, the join() method in the RecursiveAction class is called in the compute() method. The calculation results of the velocity field in all sub-areas can be combined to obtain the velocity field of the entire calculation area at a certain moment.

[0111] In addition, create an algorithm implementation class for the stress field and name it StressCalculation. This class needs to inherit the java.util.concurrent.RecursiveAction class and implement the compute() method in the RecursiveAction class. In this method, the specific calculation of the stress field at a certain moment is completed. First, in the compute() method, call the fork() function in the RecursiveAction class to divide the entire model area into sub-areas according to the above-mentioned binary method, and then use different CPU processor cores to simultaneously calculate the stress field in each sub-area according to the above-mentioned method. After the stress field in each sub-area is calculated, call the join() method in RecursiveAction in the compute() method, and combine the calculation results of the stress field in all sub-areas to obtain the stress field of the entire calculation area at a certain moment.

[0112] Based on the same inventive concept, the embodiment of the present application also provides a three-dimensional wellbore acoustic field numerical simulation device based on the Fork-Join parallel mode, which can be used to implement the method described in the above embodiment, as described in the following embodiment. Since the principle of solving the problem by the three-dimensional wellbore acoustic field numerical simulation device based on the Fork-Join parallel mode is similar to the above method, the implementation of the three-dimensional wellbore acoustic field numerical simulation device based on the Fork-Join parallel mode can refer to the implementation of the above method, and the repeated parts will not be repeated. As used below, the term "unit" or "module" can be a combination of software and / or hardware that implements a predetermined function. Although the device described in the following embodiments is preferably implemented in software, the implementation of hardware, or a combination of software and hardware, is also possible and conceived.

[0113] Fig. 9 It is the structural framework of the three-dimensional borehole acoustic field numerical simulation device based on the Fork-Join parallel mode in the embodiment of the present invention. Figure 1 .like Fig. 9 As shown, the Fork-Join-based three-dimensional borehole acoustic field numerical simulation device specifically includes: a modeling module 10, a parallel acoustic field calculation module 20, an acoustic field combination module 30 and an acoustic field result output module 40.

[0114] The modeling module 10 establishes a three-dimensional formation model according to the simulated formation geometry, geological parameter information and wellbore measurement environment, combined with dispersion conditions and stability conditions;

[0115] The parallel sound field calculation module 20 divides the three-dimensional stratum model into multiple sub-areas based on the Fork-Join parallel principle, and uses multi-core multi-threading to simultaneously calculate the sound field in each sub-area;

[0116] The sound field combination module 30 combines the sound fields in each sub-area to obtain the sound field of the entire three-dimensional formation model area;

[0117] The acoustic field result output module 40 uses a multi-unit receiver to record the acoustic field at a specified position in the three-dimensional formation model at different times, and obtains the acoustic field excited by a specific sound source in the wellbore and the formation.

[0118] The embodiment of the present invention provides a three-dimensional borehole acoustic field numerical simulation device based on the Fork-Join parallel mode. Based on the Fork-Join parallel mode, a three-dimensional borehole acoustic field numerical simulation technology suitable for Java language is proposed. The technology is simple and easy to implement, can effectively utilize the advantages of computer multi-core, improve program operation efficiency, and provide a powerful tool for the three-dimensional borehole acoustic field elastic wave numerical simulation.

[0119] In an optional embodiment, the parallel sound field calculation module includes: a finite difference calculation unit, which uses staggered grid discretization, high-order difference approximation and complex frequency shift perfectly matched layer suppression model boundary reflection to achieve finite difference calculation of the sound field in each sub-area.

[0120] In a further embodiment, the finite difference calculation unit includes: a staggered grid discretization subunit, an equation approximation subunit, a wave field preliminary calculation subunit and a wave field attenuation subunit.

[0121] Staggered grid discretization sub-units, staggered grid discretization of sub-regions to obtain the corresponding grid model;

[0122] The equation approximation subunit expresses the elastic wave equation in isotropic media in the first-order stress-velocity form and approximates the elastic wave equation in the first-order stress-velocity form by using high-order differences;

[0123] A wave field preliminary calculation subunit calculates the velocity component and the stress component in the grid model using the approximated equations, and iterates the calculation results to obtain the wave field at any time in the sub-area;

[0124] A wave field attenuation subunit calculates the attenuation term of the wave equation in the perfectly matched layer region of the sub-region, and subtracts the attenuation term from the wave field at any time in the sub-region to obtain a final wave field in the sub-region;

[0125] If the sub-region does not include a perfectly matched layer region, the corresponding attenuation term is 0.

[0126] In an optional embodiment, the parallel sound field calculation module includes: a threshold acquisition unit and a region division unit.

[0127] A threshold value acquisition unit, which obtains a threshold value according to the calculation scale of the acoustic field in the three-dimensional stratum model area and the number of cores of the computer processor;

[0128] The region division unit divides the three-dimensional stratum model into a plurality of sub-regions in a recursive manner according to the threshold.

[0129] The devices, modules or units described in the above embodiments may be implemented by computer chips or entities, or by products with certain functions. A typical implementation device is an electronic device, and the electronic device may be, for example, a personal computer, a laptop computer, a cellular phone, a camera phone, a smart phone, a personal digital assistant, a media player, a navigation device, an email device, a game console, a tablet computer, a wearable device, or a combination of any of these devices.

[0130] In a typical example, the electronic device specifically includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, the steps of the above-mentioned three-dimensional borehole acoustic field numerical simulation method based on the Fork-Join parallel mode are implemented.

[0131] Reference below Fig.10 , which shows a schematic structural diagram of an electronic device 600 suitable for implementing an embodiment of the present application.

[0132] like Fig.10As shown, electronic device 600 includes a central processing unit (CPU) 601, which can perform various appropriate operations and processes according to a program stored in a read-only memory (ROM) 602 or a program loaded from a storage portion 608 into a random access memory (RAM) 603. In RAM 603, various programs and data required for the operation of system 600 are also stored. CPU 601, ROM 602, and RAM 603 are connected to each other via a bus 604. An input / output (I / O) interface 605 is also connected to bus 604.

[0133] The following components are connected to the I / O interface 605: an input section 606 including a keyboard, a mouse, etc.; an output section 607 including a cathode ray tube (CRT), a liquid crystal display (LCD), etc., and a speaker, etc.; a storage section 608 including a hard disk, etc.; and a communication section 609 including a network interface card such as a LAN card, a modem, etc. The communication section 609 performs communication processing via a network such as the Internet. A drive 610 is also connected to the I / O interface 605 as needed. A removable medium 611, such as a magnetic disk, an optical disk, a magneto-optical disk, a semiconductor memory, etc., is installed on the drive 610 as needed, so that a computer program read therefrom is installed as needed as the storage section 608.

[0134] In particular, according to an embodiment of the present invention, the process described above with reference to the flowchart can be implemented as a computer software program. For example, an embodiment of the present invention includes a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the above-mentioned method for numerical simulation of three-dimensional borehole acoustic field based on Fork-Join parallel mode.

[0135] In such an embodiment, the computer program may be downloaded and installed from a network via the communication section 609 , and / or installed from the removable medium 611 .

[0136] Computer readable media include permanent and non-permanent, removable and non-removable media that 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.

[0137] For the convenience of description, the above device is described in various units according to their functions. Of course, when implementing the present application, the functions of each unit can be implemented in the same or multiple software and / or hardware.

[0138] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks 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 produce 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.

[0139] 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 One or more processes and / or boxes Figure 1 A function specified in one or more boxes.

[0140] 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 in the computer or other programmable device. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0141] 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.

[0142] 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 on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0143] The present application may be described in the general context of computer-executable instructions executed by a computer, such as program modules. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform specific tasks or implement specific abstract data types. The present application may also be practiced in distributed computing environments where tasks are performed by remote processing devices connected through a communication network. In a distributed computing environment, program modules may be located in local and remote computer storage media, including storage devices.

[0144] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0145] The above is only an embodiment of the present application and is 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 in the scope of the claims of the present application.

Claims

1. A three-dimensional borehole acoustic field numerical simulation method based on Fork-Join parallel mode, characterized in that: include: According to the simulated formation geometry, geological parameter information and wellbore measurement environment, a three-dimensional formation model is established in combination with dispersion conditions and stability conditions; Based on the Fork-Join parallel principle, the three-dimensional stratum model is divided into multiple sub-areas, and the acoustic field in each sub-area is calculated simultaneously by multi-core multi-threading; The sound fields in each sub-area are combined to obtain the sound field of the entire three-dimensional stratum model area; Using multi-unit receivers to record the acoustic field at a specified position in a three-dimensional formation model at different times, the acoustic field excited by a specific sound source in the wellbore and formation is obtained; The calculating the sound field in each sub-area includes: The staggered grid discretization, high-order difference approximation and complex frequency shift perfectly matched layer suppression model boundary reflection are used to achieve finite difference calculation of the sound field in each sub-area. The method adopts staggered grid discretization, high-order difference approximation and complex frequency shift perfect matching layer suppression model boundary reflection to realize finite difference calculation of the sound field in each sub-area, including: Discretize the sub-regions by staggered grids to obtain the corresponding grid model; The elastic wave equation in isotropic medium is expressed in first-order stress-velocity form, and the elastic wave equation in first-order stress-velocity form is approximated by high-order difference. Calculating the velocity component and the stress component in the grid model using the approximated equations, and iterating the calculation results to obtain the wave field at any time in the sub-area; Calculating the attenuation term of the wave equation in the perfectly matched layer region of the sub-region, and subtracting the attenuation term from the wave field at any time in the sub-region to obtain the final wave field in the sub-region; If the sub-region does not include a perfectly matched layer region, the corresponding attenuation term is 0.

2. The three-dimensional borehole acoustic field numerical simulation method based on the Fork-Join parallel mode according to claim 1 is characterized in that: The three-dimensional stratigraphic model is divided into a plurality of sub-areas, including: Obtaining a threshold value according to the calculation scale of the acoustic field in the three-dimensional stratum model area and the number of cores of a computer processor; The three-dimensional stratum model is recursively divided into a plurality of sub-areas according to the threshold.

3. A three-dimensional borehole acoustic field numerical simulation device based on Fork-Join parallel mode, characterized in that: include: Modeling module, which establishes a three-dimensional formation model based on simulated formation geometry, geological parameter information and wellbore measurement environment, combined with dispersion conditions and stability conditions; A parallel acoustic field calculation module, based on the Fork-Join parallel principle, divides the three-dimensional stratum model into multiple sub-areas, and uses multi-core multi-threading to simultaneously calculate the acoustic field in each sub-area; The sound field combination module combines the sound fields in each sub-area to obtain the sound field of the entire three-dimensional stratum model area; The acoustic field result output module uses a multi-unit receiver to record the acoustic field at a specified position in the three-dimensional formation model at different times, and obtains the acoustic field excited by a specific sound source in the wellbore and formation; The parallel sound field calculation module comprises: The finite difference calculation unit uses staggered grid discretization, high-order difference approximation and complex frequency shift perfectly matched layer suppression model boundary reflection to achieve finite difference calculation of the sound field in each sub-area; The finite difference calculation unit comprises: Staggered grid discretization sub-units, staggered grid discretization of sub-regions to obtain the corresponding grid model; The equation approximation subunit expresses the elastic wave equation in isotropic media in the first-order stress-velocity form and approximates the elastic wave equation in the first-order stress-velocity form by using high-order differences; A wave field preliminary calculation subunit calculates the velocity component and the stress component in the grid model using the approximated equations, and iterates the calculation results to obtain the wave field at any time in the sub-area; A wave field attenuation subunit calculates the attenuation term of the wave equation in the perfectly matched layer region of the sub-region, and subtracts the attenuation term from the wave field at any time in the sub-region to obtain a final wave field in the sub-region; If the sub-region does not include a perfectly matched layer region, the corresponding attenuation term is 0.

4. The three-dimensional borehole acoustic field numerical simulation device based on the Fork-Join parallel mode according to claim 3 is characterized in that: The parallel sound field calculation module comprises: A threshold value acquisition unit, which obtains a threshold value according to the calculation scale of the acoustic field in the three-dimensional stratum model area and the number of cores of the computer processor; The region division unit divides the three-dimensional stratum model into a plurality of sub-regions in a recursive manner according to the threshold.

5. An electronic device 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 program, the steps of the three-dimensional borehole acoustic field numerical simulation method based on the Fork-Join parallel mode described in any one of claims 1 to 2 are implemented.

6. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the three-dimensional borehole acoustic field numerical simulation method based on the Fork-Join parallel mode described in any one of claims 1 to 2 are implemented.

Images