Three-dimensional complex salt-containing cave geological modeling and seismic wave field numerical simulation method and device

Abstract

The application discloses a three-dimensional complex salt cavern geology modeling and seismic wave field numerical simulation method and device, relates to the technical field of seismic exploration, and accurately approaches and depicts irregular salt cavern shapes by using slice stacking technology, contour smoothing and combining a high-precision linear interpolation method, and establishes salt cavern models (including a three-dimensional salt cavern P-wave velocity model, a three-dimensional salt cavern S-wave velocity model, a three-dimensional salt cavern density model, a three-dimensional salt cavern P-wave absorption factor model and a three-dimensional salt cavern S-wave absorption factor model) that are more in line with the actual situation of the salt cavern. Furthermore, the finely constructed salt cavern model is embedded in a complex and real geological background model (a three-dimensional background stratum P-wave velocity model, a three-dimensional background stratum S-wave velocity model, a three-dimensional background stratum density model, a three-dimensional background stratum P-wave absorption factor model and a three-dimensional background stratum S-wave absorption factor model), so that a more similar simulation of an actual underground geological structure is realized.

Description

Technical Field

[0001] This application relates to the field of seismic exploration technology, and in particular to a method and apparatus for three-dimensional geological modeling of complex salt caverns and numerical simulation of seismic wave fields. Background Technology

[0002] Numerical simulation of seismic wavefields is an indispensable foundation for seismic data processing and interpretation, providing a theoretical basis for these processes. The establishment of a geological model is the starting point for numerical simulation. Currently, two-dimensional geological modeling technology is relatively mature, and a large number of powerful modeling software programs exist. However, there are many shortcomings in the establishment of three-dimensional models, making it difficult to create a satisfactory three-dimensional model that closely approximates the ideal geological body. Summary of the Invention

[0003] The purpose of this application is to provide a method and apparatus for three-dimensional complex salt cavern geological modeling and seismic wave field numerical simulation, which can more realistically simulate the actual underground geological structure of complex salt cavern geology.

[0004] To achieve the above objectives, this application provides the following solution:

[0005] Firstly, this application provides a three-dimensional geological modeling method for complex salt caverns, including:

[0006] Geological parameters of salt cavern geology are obtained; the geological parameters include the P-wave velocity, S-wave velocity, density, P-wave absorption factor, and S-wave absorption factor of each stratum, and the P-wave velocity, S-wave velocity, density, P-wave absorption factor, and S-wave absorption factor of the salt cavern.

[0007] A three-dimensional background P-wave velocity model is established based on the P-wave velocity of each stratum.

[0008] A three-dimensional longitudinal wave velocity model of salt caves was established based on the longitudinal wave velocity of salt caves, slice stacking technique, and linear interpolation method.

[0009] The three-dimensional salt cavern P-wave velocity model is embedded into the three-dimensional background strata P-wave velocity model to obtain a complete P-wave velocity model of the salt cavern-bearing geology.

[0010] Based on the complete P-wave velocity model of salt cavern geology, complete S-wave velocity model, complete density model, complete P-wave absorption factor model and complete S-wave absorption factor model of salt cavern geology are established.

[0011] A three-dimensional complex salt cave geological model is derived based on the complete P-wave velocity model, complete S-wave velocity model, complete density model, complete P-wave absorption factor model, and complete S-wave absorption factor model of salt cave geology.

[0012] Secondly, this application provides a numerical simulation method for seismic wavefields based on a three-dimensional complex salt cavern geological model, the numerical simulation method for seismic wavefields comprising:

[0013] A three-dimensional complex salt cave geological model is invoked; the three-dimensional complex salt cave geological model is constructed based on the aforementioned three-dimensional complex salt cave geological modeling method;

[0014] Finite difference numerical simulation was performed on a three-dimensional complex salt cave geological model to obtain seismic records and wavefield snapshots. During the finite difference numerical simulation, the three-dimensional complex salt cave geological model was divided into multiple grid domains by cutting it in the x, y, and z directions after meshing. Each grid domain was subjected to finite difference numerical simulation by a processor.

[0015] Thirdly, this application provides a three-dimensional complex salt cave geological modeling device, comprising:

[0016] The parameter acquisition module is used to acquire geological parameters of the salt cavern geology; the geological parameters include the formation P-wave velocity, formation S-wave velocity, formation density, formation P-wave absorption factor, formation S-wave absorption factor, and salt cavern P-wave velocity, salt cavern S-wave velocity, salt cavern density, salt cavern P-wave absorption factor, and salt cavern S-wave absorption factor of each stratum.

[0017] The background formation P-wave velocity model construction module is used to build a three-dimensional background formation P-wave velocity model based on the formation P-wave velocity of each stratum.

[0018] The salt cave P-wave velocity model construction module is used to build a three-dimensional salt cave P-wave velocity model based on the salt cave P-wave velocity, slice stacking technique, and linear interpolation method.

[0019] A complete P-wave velocity model construction module is used to embed the three-dimensional salt cave P-wave velocity model into the three-dimensional background strata P-wave velocity model to obtain a complete P-wave velocity model of the salt cave geological formation.

[0020] The parameter modification module is used to establish complete shear wave velocity models, complete density models, complete P-wave absorption factor models, and complete shear wave absorption factor models for salt cavern geology based on the complete P-wave velocity model of the salt cavern geology.

[0021] The module for constructing complex salt cave geological models is used to derive three-dimensional complex salt cave geological models based on complete P-wave velocity models, complete S-wave velocity models, complete density models, complete P-wave absorption factor models, and complete S-wave absorption factor models of salt cave geology.

[0022] Fourthly, this application provides a computer device, including: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the above-described three-dimensional complex salt cave geological modeling method or the above-described seismic wave field numerical simulation method.

[0023] Fifthly, this application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the above-described three-dimensional complex salt cave geological modeling method or the above-described seismic wave field numerical simulation method.

[0024] Sixthly, this application provides a computer program product, including a computer program that, when executed by a processor, implements the above-described three-dimensional complex salt cave geological modeling method or the above-described seismic wave field numerical simulation method.

[0025] According to the specific embodiments provided in this application, the following technical effects are disclosed:

[0026] This application provides a method and apparatus for three-dimensional complex salt cavern geological modeling and seismic wavefield numerical simulation. It employs slicing and stacking techniques, contour smoothing, and high-precision linear interpolation to accurately approximate and depict irregular salt cavern shapes, establishing salt cavern models that more closely resemble real-world conditions (including a three-dimensional salt cavern P-wave velocity model, a three-dimensional salt cavern S-wave velocity model, a three-dimensional salt cavern density model, a three-dimensional salt cavern P-wave absorption factor model, and a three-dimensional salt cavern S-wave absorption factor model). Furthermore, the meticulously constructed salt cavern model is embedded into a complex and realistic geological background model (a three-dimensional background stratum P-wave velocity model, a three-dimensional background stratum S-wave velocity model, a three-dimensional background stratum density model, a three-dimensional background stratum P-wave absorption factor model, and a three-dimensional background stratum S-wave absorption factor model), thereby achieving a more similar simulation of actual underground geological structures. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is an application environment diagram of a three-dimensional complex salt cave geological modeling method in one embodiment of this application;

[0029] Figure 2 A flowchart illustrating a three-dimensional complex salt cave geological modeling method provided in an embodiment of this application;

[0030] Figure 3 A schematic diagram of a three-dimensional longitudinal wave velocity model (indexed as distance) provided in an embodiment of this application;

[0031] Figure 4 A schematic diagram of the xy section (indexed as mesh index) of a three-dimensional longitudinal wave velocity model provided in an embodiment of this application;

[0032] Figure 5 A schematic diagram of the functional modules of a three-dimensional complex salt cave geological modeling device provided in an embodiment of this application;

[0033] Figure 6 A flowchart illustrating a numerical simulation method for seismic wavefields based on a three-dimensional complex salt cavern geological model, provided as an embodiment of this application;

[0034] Figure 7 A schematic diagram of the intermediate channel seismic record of a horizontal surface receiving array provided in an embodiment of this application;

[0035] Figure 8 A schematic diagram of receiving seismic records in a well according to an embodiment of this application;

[0036] Figure 9 This is a schematic diagram of a wave field snapshot at the location of a salt cave provided in an embodiment of this application;

[0037] Figure 10 This is a schematic diagram of the structure of a computer device provided in an embodiment of this application. Detailed Implementation

[0038] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0039] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0040] The three-dimensional complex salt cave geological modeling method provided in this application embodiment can be applied to, for example... Figure 1The application environment shown is as follows. The terminal communicates with the server via a network. The data storage system stores the data that the server needs to process. The data storage system can be set up independently, integrated into the server, or placed in the cloud or on another server. The terminal can send the collected geological parameters of the salt cavern geology to the server. After receiving the geological parameters, the server establishes a three-dimensional background stratigraphic P-wave velocity model based on the P-wave velocity of each stratum; it also establishes a three-dimensional salt cave P-wave velocity model based on the salt cavern P-wave velocity, slice stacking technology, and linear interpolation method; the three-dimensional salt cavern P-wave velocity model is embedded into the three-dimensional background stratigraphic P-wave velocity model to obtain a complete P-wave velocity model of the salt cavern geology; based on the complete P-wave velocity model of the salt cavern geology, a complete shear wave velocity model, a complete density model, a complete P-wave absorption factor model, and a complete shear wave absorption factor model of the salt cavern geology are established; based on the complete P-wave velocity model, complete shear wave velocity model, complete density model, complete P-wave absorption factor model, and complete shear wave absorption factor model of the salt cavern geology, a three-dimensional complex salt cavern geological model is obtained. The server can then feed back the obtained three-dimensional complex salt cavern geological model to the terminal. In addition, in some embodiments, the three-dimensional complex salt cave geological modeling method can also be implemented by a server or a terminal alone. For example, the terminal can directly perform three-dimensional complex salt cave geological modeling based on the geological parameters of the salt cave geology, or the server can obtain the geological parameters of the salt cave geology from the data storage system and perform three-dimensional complex salt cave geological modeling.

[0041] The terminal can be, but is not limited to, various desktop computers, laptops, smartphones, tablets, IoT devices, and portable wearable devices. The server can be a standalone server or a server cluster composed of multiple servers, or it can be a cloud server.

[0042] In one exemplary embodiment, such as Figure 2 As shown, a method for modeling complex three-dimensional salt cavern geology is provided. This method is executed by a computer device, specifically by a terminal or server alone, or by both a terminal and a server. In this embodiment, the method is applied to... Figure 1 Taking the server in the example, the explanation includes the following steps 101 to 106. Wherein:

[0043] Step 101: Obtain the geological parameters of the salt cavern geology.

[0044] To simulate seismic waves, reasonable geological parameters should be set according to the simulation requirements. Reasonable means that the parameter settings conform to geological and physical principles. Specific geological parameters include: the P-wave velocity, S-wave velocity, density, P-wave absorption factor, and S-wave absorption factor of each stratum, and the P-wave velocity, S-wave velocity, density, P-wave absorption factor, and S-wave absorption factor of salt caverns.

[0045] Step 102: Establish a three-dimensional background stratum P-wave velocity model based on the P-wave velocity of each stratum.

[0046] Step 103: Establish a three-dimensional salt cave longitudinal wave velocity model based on the salt cave longitudinal wave velocity, slice stacking technique, and linear interpolation method.

[0047] Step 104: Embed the three-dimensional salt cavern P-wave velocity model into the three-dimensional background strata P-wave velocity model to obtain a complete P-wave velocity model of the salt cavern-bearing geology. For example... Figure 3 As shown, this is the complete three-dimensional P-wave velocity model. Figure 4 As shown, an xy section of a three-dimensional P-wave velocity model is captured. This model simulates a situation where salt caverns are present in a complex stratum. Compared to 2-dimensional and 2.5-dimensional cases, this three-dimensional P-wave velocity model is closer to the actual distribution of underground structures.

[0048] In MATLAB, the irregular three-dimensional salt cave P-wave velocity model established in step 103 is embedded into the three-dimensional background strata P-wave velocity model established in step 102 using the assignment method to obtain a complete P-wave velocity model. The assignment method replaces a portion of the three-dimensional matrix of the background strata P-wave velocity model with the three-dimensional matrix of the salt cave P-wave velocity model.

[0049] Step 105: Based on the complete P-wave velocity model of the salt cavern geology, establish the complete S-wave velocity model, complete density model, complete P-wave absorption factor model, and complete S-wave absorption factor model of the salt cavern geology.

[0050] Step 106: Based on the complete P-wave velocity model, complete S-wave velocity model, complete density model, complete P-wave absorption factor model, and complete S-wave absorption factor model of the salt cavern geology, a three-dimensional complex salt cavern geological model is derived.

[0051] By implementing steps 101 to 106 above, the modeling method of this application approximates the irregular shape of salt caves by combining slice accumulation, contour smoothing and trilinear interpolation. Then, the irregular salt caves are embedded in a relatively complex geological background model to simulate the actual underground geological structure.

[0052] In another exemplary embodiment of this application, step 102, establishing a three-dimensional background P-wave velocity model based on the P-wave velocities of each stratum, specifically includes:

[0053] (1) Using seismic velocity modeling software, an uneven two-dimensional layered P-wave velocity model containing faults was established based on the P-wave velocity of each stratum.

[0054] A two-dimensional layered P-wave velocity model containing faults was created using the professional seismic velocity modeling software Tesseral2D and saved as a text document.

[0055] (2) The uneven two-dimensional layered P-wave velocity model containing faults is converted into a three-dimensional background stratum P-wave velocity model.

[0056] Use MATLAB code to convert the specially formatted (txt) data from the Tesseral2D output document into a two-dimensional matrix in MATLAB. Then, use MATLAB to copy and tile the two-dimensional matrix to convert it into a three-dimensional matrix, thus obtaining a three-dimensional background P-wave velocity model.

[0057] In another exemplary embodiment of this application, step 103, establishing a three-dimensional salt cave longitudinal wave velocity model based on the salt cave longitudinal wave velocity, slice stacking technique, and linear interpolation method, specifically includes:

[0058] (1) Select slices of different geometric shapes according to the irregular shape of the salt cave.

[0059] (2) Based on the irregular shape of the salt cave, slices of different geometric shapes are superimposed, and a preliminary salt cave longitudinal wave velocity model is constructed using the salt cave longitudinal wave velocity as an index.

[0060] Using a slice overlay technique, where slices can be of various shapes, such as circles or polygons, these individual slices are combined through written code to obtain the approximate shape of the salt cave model.

[0061] Geological P-wave velocity modeling uses P-wave velocity as an index for direct modeling, so shape modeling is completed simultaneously with velocity modeling. P-wave velocity modeling and shape modeling are performed concurrently.

[0062] (3) The contour edges of the preliminary salt cave longitudinal wave velocity model are smoothed to obtain the smoothed salt cave longitudinal wave velocity model.

[0063] The outline edge of the initially established salt cave longitudinal wave velocity model has strong unevenness. A smoothing function is used to smooth the outline edge of the salt cave longitudinal wave velocity model, making the salt cave closer to the real shape.

[0064] (4) The smoothed salt cave longitudinal wave velocity model is interpolated using the trilinear interpolation method to obtain the required three-dimensional salt cave longitudinal wave velocity model.

[0065] The purpose of trilinear interpolation is to adjust the size of the P-wave velocity model as needed.

[0066] In another exemplary embodiment of this application, a complete shear wave velocity model, a complete density model, a complete P-wave absorption factor model, and a complete shear wave absorption factor model are established in MATLAB using the established complete P-wave velocity model. Specifically, conditional statements and assignment statements are used to modify the P-wave velocity values ​​in the P-wave velocity model to the other geological parameter values ​​set in step 101, and the three-dimensional matrix representing the model is stored as a binary file. Therefore, step 105, establishing the complete shear wave velocity model, complete density model, complete P-wave absorption factor model, and complete shear wave absorption factor model of the salt cavern geology based on the complete P-wave velocity model of the salt cavern geology, specifically includes:

[0067] (1) Replace the formation P-wave velocity and salt cave P-wave velocity in the complete P-wave velocity model with the formation S-wave velocity and salt cave S-wave velocity, respectively, to obtain the complete S-wave velocity model of salt cave geology.

[0068] (2) Replace the formation P-wave velocity and salt cave P-wave velocity in the complete P-wave velocity model with formation density and salt cave density respectively to obtain the complete density model of salt cave geology.

[0069] (3) Replace the formation P-wave velocity and salt cave P-wave velocity in the complete P-wave velocity model with the formation P-wave absorption factor and the salt cave P-wave absorption factor, respectively, to obtain the complete P-wave absorption factor model of salt cave geology.

[0070] (4) Replace the formation P-wave velocity and salt cave P-wave velocity in the complete P-wave velocity model with the formation S-wave absorption factor and the salt cave S-wave absorption factor, respectively, to obtain the complete S-wave absorption factor model of salt cave geology.

[0071] As another optional implementation, in step 105, establishing a complete shear wave velocity model, a complete density model, a complete P-wave absorption factor model, and a complete shear wave absorption factor model for the salt cavern geology can adopt the construction process of the complete P-wave velocity model. Specifically:

[0072] (1) Based on the shear wave velocity, density, P-wave absorption factor and shear wave absorption factor of each stratum, three-dimensional background shear wave velocity model, three-dimensional background stratum density model, three-dimensional background stratum P-wave absorption factor model and three-dimensional background stratum shear wave absorption factor model are established respectively.

[0073] (2) Based on the shear wave velocity, density, longitudinal wave absorption factor and shear wave absorption factor of the salt cave, three-dimensional salt cave shear wave velocity model, three-dimensional salt cave density model, three-dimensional salt cave longitudinal wave absorption factor model and three-dimensional salt cave shear wave absorption factor model are established by applying slice stacking technology and linear interpolation method respectively.

[0074] Based on the smoothed salt cave longitudinal wave velocity model described above, the salt cave transverse wave velocity, salt cave density, salt cave longitudinal wave absorption factor, and salt cave transverse wave absorption factor can be interpolated using linear interpolation.

[0075] (3) The three-dimensional salt cave shear wave velocity model is embedded into the three-dimensional background stratum shear wave velocity model to obtain a complete shear wave velocity model; the three-dimensional salt cave density model is embedded into the three-dimensional background stratum density model to obtain a complete density model; the three-dimensional salt cave P-wave absorption factor model is embedded into the three-dimensional background stratum P-wave absorption factor model to obtain a complete P-wave absorption factor model; the three-dimensional salt cave shear wave absorption factor model is embedded into the three-dimensional background stratum shear wave absorption factor model to obtain a complete shear wave absorption factor model.

[0076] This application ingeniously employs slice accumulation technology, combined with various high-precision interpolation methods, to accurately approximate and depict the irregular shape of salt caverns. Subsequently, this meticulously constructed salt cavern model is embedded into a complex and realistic geological background model, thereby achieving a more similar simulation of actual underground geological structures. Furthermore, seismic wave numerical simulations were performed on this model using finite difference numerical simulations to verify its application effectiveness in seismic exploration.

[0077] Based on the same inventive concept, this application also provides a three-dimensional complex salt cave geological modeling device for implementing the three-dimensional complex salt cave geological modeling method described above. The solution provided by this device is similar to the solution described in the above method. Therefore, the specific limitations of one or more embodiments of the three-dimensional complex salt cave geological modeling device provided below can be found in the limitations of the three-dimensional complex salt cave geological modeling method described above, and will not be repeated here.

[0078] In one exemplary embodiment, such as Figure 5 As shown, a three-dimensional complex salt cave geological modeling device is provided, comprising:

[0079] The parameter acquisition module M1 is used to acquire geological parameters of the salt cavern geology; the geological parameters include the formation P-wave velocity, formation S-wave velocity, formation density, formation P-wave absorption factor, formation S-wave absorption factor of each stratum, and salt cavern P-wave velocity, salt cavern S-wave velocity, salt cavern density, salt cavern P-wave absorption factor, and salt cavern S-wave absorption factor of each salt cavern.

[0080] The background stratum P-wave velocity model construction module M2 is used to build a three-dimensional background stratum P-wave velocity model based on the P-wave velocity of each stratum.

[0081] The salt cave P-wave velocity model building module M3 is used to build a three-dimensional salt cave P-wave velocity model based on the salt cave P-wave velocity, slice stacking technique, and linear interpolation method.

[0082] The complete P-wave velocity model construction module M4 is used to embed the three-dimensional salt cave P-wave velocity model into the three-dimensional background strata P-wave velocity model to obtain a complete P-wave velocity model of the salt cave geological formation.

[0083] The parameter modification module M5 is used to establish complete shear wave velocity models, complete density models, complete P-wave absorption factor models, and complete shear wave absorption factor models for salt cavern geology based on the complete P-wave velocity model of the salt cavern geology.

[0084] The Complex Salt Cavern Geological Model Construction Module M6 is used to derive a three-dimensional complex salt cavern geological model based on the complete P-wave velocity model, complete S-wave velocity model, complete density model, complete P-wave absorption factor model, and complete S-wave absorption factor model of the salt cavern geology.

[0085] In another exemplary embodiment of this application, mature methods for numerical simulation of seismic wavefields include the finite difference method, the spectral element method, and the finite element method. The finite difference method has advantages such as fast computation speed and strong applicability to near and far wavefields and complex boundaries, and is therefore widely used in two-dimensional seismic wavefield numerical simulation. With the continuous improvement of computer performance, the finite difference method has also been applied to three-dimensional seismic wavefield numerical simulation. However, due to the enormous computational load of three-dimensional numerical simulation, the computational efficiency for simulating large models remains unsatisfactory. In recent years, GPU parallelism and other methods have been commonly used to improve computational efficiency. For low-velocity bodies within complex models, the numerical simulation results often show weak signals. Solving the problems of computational efficiency and signal reception is of great significance for the numerical simulation of seismic wavefields. Therefore, this application proposes a seismic wavefield numerical simulation method based on a three-dimensional complex salt cavern geological model, comprising:

[0086] Step 201: Call the three-dimensional complex salt cave geological model; the three-dimensional complex salt cave geological model is constructed based on the aforementioned three-dimensional complex salt cave geological modeling method.

[0087] Step 202: Perform finite difference numerical simulation on the 3D complex salt cavern geological model to obtain seismic records and wavefield snapshots. During the finite difference numerical simulation, the meshed 3D complex salt cavern geological model is divided into multiple mesh domains along the x, y, and z directions. Each mesh domain is processed by a processor to perform the finite difference numerical simulation. The final 3D model remains 3D after the meshing is completed.

[0088] The following is a more complete and detailed flowchart of the numerical simulation method for seismic wavefields in viscoelastic media, with each step implemented using a program compiled in C language. Figure 6 As shown.

[0089] The first step is to import the three-dimensional complex salt cave geological model.

[0090] The binary files of the five models (complete P-wave velocity model, complete S-wave velocity model, complete density model, complete P-wave absorption factor model, and complete S-wave absorption factor model) generated by the above modeling method are read into the C language code.

[0091] The second step is to generate the seismic source and determine its location.

[0092] When generating the seismic source, this application uses the Ricker wavelet as the wavelet signal to write a source function; other wavelets can also be used. The Ricker wavelet signal is:

[0093] r(τ)=(1-2τ 2 )exp(-τ 2 )

[0094]

[0095] Where r(τ) is the wavelet signal, t is time, and f c For the center frequency, t d This is a time delay.

[0096] The third step is to set up a receiving array to solve the aforementioned signal reception problem.

[0097] In order to obtain better numerical simulation results, a method of coordinated reception above and below ground is adopted. A plane geophone array is set up on the surface, and geophones are arranged in the well to receive seismic wave transmission and reflection information from the side.

[0098] The fourth step is to verify the input parameters and check whether the source location generated in the second step and the detector location set in the third step match the model read in the sixth step.

[0099] In this context, "matching" means that the position of the detector cannot exceed the size of the model.

[0100] Input parameters refer to the aforementioned geological parameters. Verification is necessary because the input parameters cannot violate physical principles. For example, if the shear wave velocity in a complex 3D salt cavern geological model is 0, the simulation will fail because viscoelastic waves cannot be simulated in pure fluid. If the parameters do not conform to physical principles, the numerical simulation process will fail.

[0101] Step 5: Grid division.

[0102] Grid generation specifically includes:

[0103] Sub-step 1: Discretize and mesh the imported 3D complex salt cave geological model. The mesh size is NX×NY×NZ, where NX is the total number of mesh points in the x-direction, NY is the total number of mesh points in the y-direction, NZ is the total number of mesh points in the z-direction, the spatial step size in the x-direction is DX, the spatial step size in the y-direction is DY, and the spatial step size in the z-direction is DZ.

[0104] Sub-step 2: Divide the 3D mesh to improve computational efficiency. Specifically, cut the entire 3D mesh model in the x, y, and z directions to make the entire model into nx×ny×nz mesh domains, where nx is the number of processors in the x direction, ny is the number of processors in the y direction, and nz is the number of processors in the z direction. The total number of processors occupied is nx×ny×nz, and the size of nx, ny, and nz can be adjusted according to the performance of the computing device.

[0105] This step can accelerate computational efficiency and solve the aforementioned computational efficiency problem. The parallel method in this application is MPI parallelism. The difference between MPI parallelism and GPU parallelism can be understood as follows: MPI parallelism uses the CPU, while GPU parallelism is based on the GPU (the core component of a graphics card, a processor designed specifically for parallel computing).

[0106] Step 6: Algorithm stability verification, i.e., numerical simulation stability check. If the grid and time step settings are unreasonable, the numerical simulation process will become unstable, causing the calculation to stop. Ensuring algorithm stability requires the following conditions:

[0107]

[0108] Where dh is the spatial step size; dh is the maximum value among DX, DY, and DZ in the fifth step; V s,min It is the minimum transverse wave velocity; f max It is twice the center frequency; n is a parameter related to the finite difference order.

[0109]

[0110] Where DT is the time step; v p-maxis the maximum P-wave velocity; h is a parameter related to the finite difference operator and type.

[0111] The numerical simulation process can only proceed normally when DT and dh satisfy the above formula; otherwise, it will directly cause the algorithm program to crash.

[0112] Step 7: Set boundary conditions in the three-dimensional complex salt cave geological model.

[0113] The surface is set as a free surface, and only horizontal particle velocities are used when updating stress components on the free surface. The four sides and bottom of the model mesh are absorbing boundaries. The absorbing boundary conditions use PML (Perfectly Matched Layers). Generally, setting the boundary thickness L to 20 meshes is sufficient to achieve good absorption of seismic waves. If no absorbing boundary is set, seismic waves will produce strong reflections at the boundary, affecting the simulation results. The specific form of the damping function involved in the absorbing boundary is as follows:

[0114]

[0115] Where c is the damping function, V pml It is the longitudinal wave velocity within the medium, α = 10. -4 L is the thickness of the absorbing boundary layer.

[0116] The attenuation factor involved in the absorption boundary is:

[0117]

[0118] Where dx(x), dy(y), and dz(z) are attenuation factors. The wave needs to be absorbed when it propagates to the boundary, otherwise false reflections will occur at the interface. Therefore, the signal is absorbed by attenuation factors in three directions; x is the grid point position in the x direction; y is the grid point position in the y direction; and z is the grid point position in the z direction. This is an adjustment coefficient used to adjust the intensity of boundary absorption.

[0119] Step 8: After completing steps 1 through 7 above, perform high-order finite difference numerical simulation.

[0120] Sub-step 1: The numerical simulation in this application is based on the stress-strain equation of viscoelastic media:

[0121] When i = j

[0122] When i≠j

[0123] Where, r ij For memory variables, the following relationship exists:

[0124] When i≠j

[0125] When i = j

[0126] Momentum conservation equation:

[0127]

[0128] Among them, (i, j, k = x, y, z), σ ij Let x be the ij-th stress tensor. ij Let ν be the coordinate in the direction of ij. k x k The velocity and coordinate in the k-direction are respectively, τ σ ν is the relaxation coefficient. i x i f i These represent the velocity, coordinate, and external force in the i-direction, respectively; ρ is the density; τ p It is twice the reciprocal of the longitudinal wave absorption factor; τ s It is twice the reciprocal of the transverse wave absorption factor; M and μ are parameters used to limit the phase velocities of the P and S waves at the center frequency of the seismic source.

[0129] Sub-step 2: Discretize the above equations, approximating the time differential with a second-order central difference and the spatial differential with a fourth-order staggered central difference. Introduce the fourth-order staggered difference:

[0130]

[0131] Where i is the grid point position, h is the grid spacing, and the difference is... and Approximate the equation f(x) in and The derivative at point [x]. This describes a mathematical approximation method that replaces the differentiation in sub-step 1 with finite differences. f(x) is the equation that needs to be differentiated, and this finite difference method is used to solve for the partial derivative with respect to sub-step 1.

[0132] The partial derivative in the time domain is approximately:

[0133]

[0134] In the formula, i, j, k, n are discrete representations of x, y, z, t, where x, y, z, t represent spatial location and time.

[0135] The two formulas for calculating partial derivatives in sub-step 2 are mathematically referred to as operators, which are a way to calculate partial derivatives. The partial derivatives in sub-step 1 are calculated by these two operators. Therefore, substituting the operators in sub-step 2 into the equations of sub-step 1 yields the detailed finite difference equations.

[0136] Sub-step 3: Based on the finite difference equation, perform parallel numerical simulation according to the aforementioned grid domain division to obtain simulation data, and generate seismic records and wavefield snapshots for each grid domain.

[0137] Sub-step 4: Merge the wave field snapshots of each grid domain.

[0138] This application provides a method for three-dimensional geological modeling of complex salt caverns and its seismic wavefield numerical simulation. This method cleverly utilizes slice accumulation technology and combines it with various high-precision interpolation methods to accurately approximate and depict the irregular shapes of salt caverns. Subsequently, this meticulously constructed salt cavern model is embedded into a complex and realistic geological background model, thereby achieving a more similar simulation of actual underground geological structures. In the seismic data reception stage, an advanced method of combined surface and downhole acquisition is employed. This method significantly improves the quality of seismic data, ensuring the acquisition of more accurate and comprehensive underground information. Furthermore, some effective methods are incorporated into certain steps of the numerical simulation, such as improving computational efficiency through parallel processing and using more sophisticated boundary absorbing methods. Figure 7 To Figure 3 The seismic records received at the Earth's surface after numerical simulation using a three-dimensional P-wave velocity model. Figure 8 To Figure 3 The seismic records received in the well after numerical simulation of the three-dimensional P-wave velocity model are obtained through the joint receiving method between the well and the surface, which makes the information more complete and facilitates subsequent inversion. Figure 9 To Figure 3 A snapshot of the wave field at the salt cave location when the seismic wave propagates in numerical simulation using a three-dimensional P-wave velocity model shows that the seismic wave can propagate normally in this model.

[0139] This application also provides an application scenario in which the aforementioned three-dimensional complex salt cave geological modeling method and seismic wavefield numerical simulation method are applied. Specifically, the three-dimensional complex salt cave geological modeling method and seismic wavefield numerical simulation method provided in this embodiment can be applied in a seismic wavefield numerical simulation scenario. This scenario includes a parameter acquisition stage for acquiring relevant geological parameters; a modeling stage for constructing a three-dimensional complex salt cave geological model; and a numerical simulation stage for performing seismic wavefield numerical simulation based on the three-dimensional complex salt cave geological model. In this embodiment, the three-dimensional complex salt cave geological modeling method belongs to the modeling stage, and the seismic wavefield numerical simulation method belongs to the numerical simulation stage.

[0140] In one exemplary embodiment, a computer device is provided, which may be a server or a terminal, and its internal structure diagram may be as follows. Figure 10 As shown, this computer device includes a processor, memory, input / output (I / O) interfaces, and a communication interface. The processor, memory, and I / O interfaces are connected via a system bus, and the communication interface is also connected to the system bus via the I / O interfaces. The processor provides computational and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system, computer programs, and a database. The internal memory provides the environment for the operating system and computer programs stored in the non-volatile storage media. The database stores relevant data from the three-dimensional complex salt cave geological modeling process and relevant data from the seismic wavefield numerical simulation process. The I / O interfaces are used for information exchange between the processor and external devices. The communication interface is used for communication with external terminals via a network connection. When the computer program is executed by the processor, it implements a three-dimensional complex salt cave geological modeling method or a seismic wavefield numerical simulation method based on a three-dimensional complex salt cave geological model.

[0141] Those skilled in the art will understand that Figure 10 The structures shown are merely block diagrams of some structures related to the present application and do not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than shown in the figures, or combine certain components, or have different component arrangements. In an exemplary embodiment, a computer device is provided, including a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the steps in the above-described method embodiments.

[0142] In one exemplary embodiment, a computer-readable storage medium is provided storing a computer program that, when executed by a processor, implements the steps in the above-described method embodiments.

[0143] In one exemplary embodiment, a computer program product is provided, including a computer program that, when executed by a processor, implements the steps in the above-described method embodiments.

[0144] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, data stored, data displayed, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of the relevant data must comply with relevant regulations.

[0145] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM).

[0146] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0147] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. Furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A method for three-dimensional geological modeling of complex salt caverns, characterized in that, The three-dimensional complex salt cavern geological modeling method comprises the following steps: obtaining geological parameters of the salt cavern geological formation; the geological parameters comprise formation P-wave velocity, formation S-wave velocity, formation density, formation P-wave absorption factor, formation S-wave absorption factor, and salt cavern P-wave velocity, salt cavern S-wave velocity, salt cavern density, salt cavern P-wave absorption factor, and salt cavern S-wave absorption factor in the salt cavern; establishing a three-dimensional background formation P-wave velocity model according to the formation P-wave velocity of each formation; establishing a three-dimensional salt cavern P-wave velocity model according to the salt cavern P-wave velocity in the salt cavern, slice stacking technology, and linear interpolation method; embedding the three-dimensional salt cavern P-wave velocity model into the three-dimensional background formation P-wave velocity model to obtain a complete P-wave velocity model of the salt cavern geological formation; establishing a complete S-wave velocity model, a complete density model, a complete P-wave absorption factor model, and a complete S-wave absorption factor model of the salt cavern geological formation according to the complete P-wave velocity model of the salt cavern geological formation; obtaining a three-dimensional complex salt cavern geological model according to the complete P-wave velocity model, the complete S-wave velocity model, the complete density model, the complete P-wave absorption factor model, and the complete S-wave absorption factor model of the salt cavern geological formation; wherein the complete S-wave velocity model, the complete density model, the complete P-wave absorption factor model, and the complete S-wave absorption factor model of the salt cavern geological formation are established according to the complete P-wave velocity model of the salt cavern geological formation, and specifically comprise the following steps: replacing the formation P-wave velocity and the salt cavern P-wave velocity in the complete P-wave velocity model with formation S-wave velocity and salt cavern S-wave velocity respectively to obtain the complete S-wave velocity model of the salt cavern geological formation; replacing the formation P-wave velocity and the salt cavern P-wave velocity in the complete P-wave velocity model with formation density and salt cavern density respectively to obtain the complete density model of the salt cavern geological formation; replacing the formation P-wave velocity and the salt cavern P-wave velocity in the complete P-wave velocity model with formation P-wave absorption factor and salt cavern P-wave absorption factor respectively to obtain the complete P-wave absorption factor model of the salt cavern geological formation; replacing the formation P-wave velocity and the salt cavern P-wave velocity in the complete P-wave velocity model with formation S-wave absorption factor and salt cavern S-wave absorption factor respectively to obtain the complete S-wave absorption factor model of the salt cavern geological formation.

2. The method of claim 1, wherein, The three-dimensional background formation P-wave velocity model is established according to the formation P-wave velocity of each formation, and specifically comprises the following steps: using a seismic velocity model modeling software to establish a two-dimensional uneven layered P-wave velocity model containing faults according to the formation P-wave velocity of each formation; converting the two-dimensional uneven layered P-wave velocity model containing faults into the three-dimensional background formation P-wave velocity model.

3. The method of claim 1, wherein, The three-dimensional salt cavern P-wave velocity model is established according to the salt cavern P-wave velocity in the salt cavern, slice stacking technology, and linear interpolation method, and specifically comprises the following steps: selecting different geometric shapes of slices according to the irregular shape of the salt cavern; stacking the slices of different geometric shapes according to the irregular shape of the salt cavern, and constructing a preliminary salt cavern P-wave velocity model with the salt cavern P-wave velocity as an index; smoothing the contour edges of the preliminary salt cavern P-wave velocity model to obtain a smoothed salt cavern P-wave velocity model; The three-dimensional salt cavern P-wave velocity model of the required size is obtained by using the trilinear interpolation method to interpolate the smoothed salt cavern P-wave velocity model.

4. A method for numerical simulation of seismic wave field based on a three-dimensional complex salt-containing cave geological model, characterized in that, The seismic wave field numerical simulation method comprises: calling a three-dimensional complex salt cavern containing geological model; the three-dimensional complex salt cavern containing geological model is constructed based on the three-dimensional complex salt cavern containing geological modeling method according to any one of claims 1 to 3; performing finite difference numerical simulation on the three-dimensional complex salt cavern containing geological model to obtain seismic records and wave field snapshots; when performing the finite difference numerical simulation, the three-dimensional complex salt cavern containing geological model after the grid division is cut in the x direction, the y direction and the z direction to divide the entire three-dimensional model into a plurality of grid domains; each grid domain is executed by a processor to perform the finite difference numerical simulation.

5. A device for three-dimensional complex salt cavern geologic modeling, characterized in that, The three-dimensional complex salt cavern containing geological modeling device comprises: a parameter acquisition module configured to acquire geological parameters of the salt cavern containing geological formation; the geological parameters comprise formation P-wave velocity, formation S-wave velocity, formation density, formation P-wave absorption factor, formation S-wave absorption factor of each formation, and salt cavern P-wave velocity, salt cavern S-wave velocity, salt cavern density, salt cavern P-wave absorption factor, and salt cavern S-wave absorption factor in the salt cavern; a background formation P-wave velocity model construction module configured to establish a three-dimensional background formation P-wave velocity model according to the formation P-wave velocity of each formation; a salt cavern P-wave velocity model construction module configured to establish a three-dimensional salt cavern P-wave velocity model according to the salt cavern P-wave velocity in the salt cavern, the slice stacking technology and the linear interpolation method; a complete P-wave velocity model construction module configured to embed the three-dimensional salt cavern P-wave velocity model into the three-dimensional background formation P-wave velocity model to obtain a complete P-wave velocity model of the salt cavern containing geological formation; a parameter modification module configured to establish a complete S-wave velocity model, a complete density model, a complete P-wave absorption factor model and a complete S-wave absorption factor model of the salt cavern containing geological formation according to the complete P-wave velocity model of the salt cavern containing geological formation; wherein the complete S-wave velocity model, the complete density model, the complete P-wave absorption factor model and the complete S-wave absorption factor model of the salt cavern containing geological formation are established according to the complete P-wave velocity model of the salt cavern containing geological formation, and specifically include: replacing the formation P-wave velocity and the salt cavern P-wave velocity in the complete P-wave velocity model with the formation S-wave velocity and the salt cavern S-wave velocity respectively to obtain the complete S-wave velocity model of the salt cavern containing geological formation; replacing the formation P-wave velocity and the salt cavern P-wave velocity in the complete P-wave velocity model with the formation density and the salt cavern density respectively to obtain the complete density model of the salt cavern containing geological formation; replacing the formation P-wave velocity and the salt cavern P-wave velocity in the complete P-wave velocity model with the formation P-wave absorption factor and the salt cavern P-wave absorption factor respectively to obtain the complete P-wave absorption factor model of the salt cavern containing geological formation; replacing the formation P-wave velocity and the salt cavern P-wave velocity in the complete P-wave velocity model with the formation S-wave absorption factor and the salt cavern S-wave absorption factor respectively to obtain the complete S-wave absorption factor model of the salt cavern containing geological formation; The complex salt cavern geology model construction module is used to derive a three-dimensional complex salt cavern geology model according to a complete P-wave velocity model, a complete S-wave velocity model, a complete density model, a complete P-wave absorption factor model and a complete S-wave absorption factor model of the salt cavern geology.

6. A computer device comprising: The memory, the processor and the computer program stored in the memory and executable on the processor, characterized in that the processor executes the computer program to implement the three-dimensional complex salt cavern geology modeling method of any one of claims 1-3 or the seismic wave field numerical simulation method of claim 4.

7. A computer-readable storage medium having stored thereon a computer program, characterized in that The computer program is executed by the processor to implement the three-dimensional complex salt cavern geology modeling method of any one of claims 1-3 or the seismic wave field numerical simulation method of claim 4.

8. A computer program product comprising a computer program, characterized in that, The computer program is executed by the processor to implement the three-dimensional complex salt cavern geology modeling method of any one of claims 1-3 or the seismic wave field numerical simulation method of claim 4. The computer program is executed by the processor to implement the three-dimensional complex salt cavern geology modeling method of any one of claims 1-3 or the seismic wave field numerical simulation method of claim 4.

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