VSP observation method and system for multi-scale fracture three-dimensional geological model

Abstract

The present invention provides a VSP observation method and system for a multi-scale fracture three-dimensional geological model. The method comprises: establishing a seismic wave field propagation model according to a preset multi-scale fracture three-dimensional grid forward geological model; solving the seismic wave field propagation model by a finite difference method to obtain wave field values; determining the wave field values ​​corresponding to the detector positions in the seismic wave field propagation model to output three-component seismic data of a vertical seismic profile. The present invention can simulate the propagation process of the seismic wave field in a complex fracture stratum, and finally realize VSP observation.

Description

Technical Field

[0001] The present invention relates to the technical field of exploration seismology, and in particular to a VSP observation method and system for a multi-scale fracture three-dimensional geological model. Background Art

[0002] With the rapid development of the petroleum industry, the objectives of oil and gas exploration have become more and more complex, and more and more exploration work has been carried out on fractured oil and gas reservoirs. Fractures are very important oil and gas migration and storage spaces. They are widely distributed in the strata, and their seismic response characteristics are also very complex. Correctly understanding the development characteristics and fluid content of fractures through seismic response characteristics is of great significance for the exploration of fractured oil and gas reservoirs. Summary of the invention

[0003] One object of the present invention is to provide a multi-scale fracture three-dimensional geological model VSP observation method, simulate the propagation process of seismic wave fields in complex fractured strata, and finally realize VSP observation. Another object of the present invention is to provide a multi-scale fracture three-dimensional geological model VSP observation system. Another object of the present invention is to provide a computer device. Another object of the present invention is to provide a readable medium.

[0004] In order to achieve the above objectives, the present invention discloses, on one hand, a multi-scale fracture three-dimensional geological model VSP observation method, comprising:

[0005] Establish a seismic wave field propagation model based on the preset multi-scale fracture three-dimensional grid forward geological model;

[0006] The seismic wave field propagation model is solved by the finite difference method to obtain the wave field value;

[0007] The wave field value corresponding to the detector position in the seismic wave field propagation model is determined to output the three-component seismic data of the vertical seismic profile.

[0008] Preferably, the method further comprises the step of pre-establishing the seismic wave field propagation model.

[0009] Preferably, the pre-establishing the seismic wave field propagation model specifically includes:

[0010] According to the crack parameters in the work area, the elastic coefficient matrix of small-scale horizontal cracks is calculated using the improved Husdon equivalent crack theory.

[0011] The elastic stiffness matrix of high-angle cracks is calculated based on a technique combining linear sliding theory with finite difference spatial step size;

[0012] The three-dimensional geological model is gridded, and the elastic coefficient matrix and the elastic stiffness matrix are assigned to the gridded three-dimensional geological model to obtain a seismic wave field propagation model.

[0013] Preferably, the gridding of the three-dimensional geological model specifically includes:

[0014] Small-scale cracks in the horizontal direction are considered as background media;

[0015] High-angle or vertical fractures are embedded in the background medium to form a gridded three-dimensional geological model.

[0016] Preferably, solving the seismic wave field propagation model by the finite difference method to obtain the wave field value specifically includes:

[0017] Using the finite difference method, the differential calculation is used to replace the differential operation in the seismic wave field propagation model;

[0018] The seismic wave field propagation model is solved by replacing differential operations to obtain the seismic wave field values ​​under different source excitation conditions.

[0019] The present invention also discloses a multi-scale fracture three-dimensional geological model VSP observation system, comprising:

[0020] A model building module is used to establish a seismic wave field propagation model based on a preset multi-scale fracture three-dimensional grid forward geological model;

[0021] Model solving module, used to solve the seismic wave field propagation model by finite difference method to obtain wave field value;

[0022] The seismic data output module is used to determine the wave field value corresponding to the detector position in the seismic wave field propagation model to output the three-component seismic data of the vertical seismic profile.

[0023] Preferably, it further comprises a model preset module for pre-establishing the seismic wave field propagation model.

[0024] Preferably, the model preset module is specifically used to calculate the elastic coefficient matrix of small-scale horizontal fractures based on the work area fracture parameters using the improved Husdon equivalent fracture theory; calculate the elastic stiffness matrix of high-angle fractures based on a technique combining linear sliding theory with finite difference space step size; grid the three-dimensional geological model, and assign the elastic coefficient matrix and the elastic stiffness matrix to the gridded three-dimensional geological model to obtain a seismic wave field propagation model.

[0025] Preferably, the model preset module is further used to regard small-scale fractures in the horizontal direction as background media; and embed high-angle or vertical fractures in the background media to form a gridded three-dimensional geological model.

[0026] Preferably, the model solving module is specifically used to use the finite difference method to utilize differential calculation to replace the differential operation in the seismic wave field propagation model; solve the seismic wave field propagation model replaced by differential operation to obtain the seismic wave field values ​​under different source excitation conditions.

[0027] The present invention also discloses a computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor.

[0028] When the processor executes the program, the method described above is implemented.

[0029] The present invention also discloses a computer readable medium having a computer program stored thereon.

[0030] When the program is executed by a processor, the method described above is implemented.

[0031] In order to study the propagation characteristics of seismic wave fields under common source excitation conditions in complex fractured formations and the anisotropic characteristics of fractured oil and gas reservoirs, the present invention combines the fracture medium equivalent theory and the linear sliding fracture theory to achieve rock physics modeling of multi-scale fractured media. Based on the finite difference algorithm, the propagation process of seismic wave fields in complex fractured formations is simulated, and finally VSP observation is achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0033] Figure 1 A flowchart showing a specific embodiment of the multi-scale fracture three-dimensional geological model VSP observation method of the present invention;

[0034] Figure 2 A flowchart showing a specific embodiment S000 of the multi-scale fracture three-dimensional geological model VSP observation method of the present invention;

[0035] Figure 3 A flowchart showing a specific embodiment S030 of the multi-scale fracture three-dimensional geological model VSP observation method of the present invention;

[0036] Figure 4 A flowchart showing a specific embodiment S200 of the multi-scale fracture three-dimensional geological model VSP observation method of the present invention;

[0037] Figure 5A two-dimensional schematic diagram of a fracture medium forward modeling geological model is shown in a specific embodiment of the multi-scale fracture three-dimensional geological model VSP observation method of the present invention;

[0038] Figure 6 A schematic diagram showing a VSP observation system of a specific embodiment of the VSP observation method for a multi-scale fracture three-dimensional geological model of the present invention;

[0039] Figure 7 A schematic diagram showing three-component seismic data under explosive source excitation conditions in a specific embodiment of the VSP observation method for a multi-scale fracture three-dimensional geological model of the present invention;

[0040] Figure 8 A schematic diagram showing three-component seismic data under the condition of a heavy hammer source excitation in a specific embodiment of the VSP observation method for a multi-scale fracture three-dimensional geological model of the present invention;

[0041] Fig. 9 A structural diagram showing a specific embodiment of the multi-scale fracture three-dimensional geological model VSP observation system of the present invention;

[0042] Fig.10 A structural diagram showing a specific embodiment of the multi-scale fracture three-dimensional geological model VSP observation system of the present invention, including a model preset module;

[0043] Fig.11 A schematic diagram showing the structure of a computer device suitable for implementing an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0044] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] The fractures in the strata have multi-scale and multi-angle characteristics, such as small-scale horizontal fractures and large-scale vertical fractures. Existing studies have proposed different equivalent fracture models based on the above situations, such as the Hudson fracture equivalent model (Husdon, 1980) and the linear sliding theory (Schoenberg, 1995).

[0046] As a reproduction of the seismic wave propagation process in underground media, seismic wave numerical simulation is an effective means to study the propagation characteristics of seismic wave fields and the physical parameters of underground media. It can improve the understanding of the propagation characteristics of seismic wave fields and verify the accuracy of physical models. Among the commonly used seismic wave numerical simulation methods, the finite difference method based on the wave equation theory can ensure the dynamic and kinematic characteristics of seismic waves. At the same time, the algorithm has high flexibility, so it is widely used (Virieux, 1984. Igel, 1995. Saenger, 2000).

[0047] VSP (vertical seismic profiling) technology is different from conventional ground seismic technology. It places detectors in the wellbore and sources on the surface to excite seismic waves, which can provide high-resolution seismic data and accurate velocity models, providing important support for the acquisition, processing and interpretation of conventional ground seismic data (Douglas J, 1986. Balch A, 1991. Gomes F, 2005).

[0048] According to one aspect of the present invention, this embodiment discloses a VSP observation method for a multi-scale fracture three-dimensional geological model. Figure 1 As shown, in this embodiment, the method includes:

[0049] S100: Establishing a seismic wave field propagation model based on a preset multi-scale fracture three-dimensional grid forward geological model.

[0050] S200: Solve the seismic wave field propagation model by finite difference method to obtain wave field values.

[0051] S300: Determine the wave field value corresponding to the detector position in the seismic wave field propagation model to output three-component seismic data of the vertical seismic profile.

[0052] In order to study the propagation characteristics of seismic wave fields under common source excitation conditions in complex fractured formations and the anisotropic characteristics of fractured oil and gas reservoirs, the present invention combines the fracture medium equivalent theory and the linear sliding fracture theory to achieve rock physics modeling of multi-scale fractured media. Based on the finite difference algorithm, the propagation process of seismic wave fields in complex fractured formations is simulated, and finally VSP observation is achieved.

[0053] In a preferred embodiment, the method further comprises a step S000 of pre-establishing the seismic wave field propagation model.

[0054] In a preferred embodiment, Figure 2 As shown, the S000 pre-establishing the seismic wave field propagation model specifically includes:

[0055] S010: Based on the crack parameters in the work area, the elastic coefficient matrix of small-scale horizontal cracks is calculated using the improved Husdon equivalent crack theory.

[0056] S020: Computation of the elastic stiffness matrix of high-angle cracks based on a technique combining linear sliding theory with a finite difference spatial step size.

[0057] S030: gridding the three-dimensional geological model, and assigning the elastic coefficient matrix and the elastic stiffness matrix to the gridded three-dimensional geological model to obtain a seismic wave field propagation model.

[0058] Specifically, in a specific example, the fracture parameters of the work area are obtained through logging data and geological interpretation results, such as fracture density, longitudinal wave and shear wave velocity of the background medium, etc. For small-scale horizontal fractures, the improved Husdon equivalent fracture theory is used to calculate the corresponding elastic coefficient matrix:

[0059]

[0060] Among them, λ and μ are the Lame coefficients of the isotropic background medium, and U 11 , U 33 is the fracture shear stress and tension response, which is related to the fracture density e, aspect ratio and filling material, c 11 、c 22 、c 33 、c 12 、c 13 、c 21 、c 31 、c 23 、c 32 、c 55 、c 66 and c 44 are the variables in the 6×6 elastic coefficient matrix, and the variables in the matrix are c ij , where i and j can be 1, 2, 3, 4, 5 and 6 respectively.

[0061] For large high-angle cracks formed by tectonic action, the corresponding elastic stiffness matrix is ​​calculated based on linear sliding theory combined with finite difference spatial step size:

[0062]

[0063] in:

[0064]

[0065] Among them, the parameters λ and μ are the elastic parameters of the background medium, ΔV and Δα are the volume of a single grid and the volume of the crack in the grid, respectively, and Z N , Z Tare the vertical and tangential flexibility of the crack.

[0066] In a preferred embodiment, Figure 3 As shown, the S030 gridding the three-dimensional geological model may specifically include:

[0067] S031: Small-scale cracks in the horizontal direction are considered as background media.

[0068] S032: Inlay high-angle or vertical fractures into the background medium to form a gridded three-dimensional geological model.

[0069] Specifically, the three-dimensional geological model can be gridded. For small-scale fractures in the horizontal direction, they are regarded as background media. The corresponding elastic coefficient matrix is ​​calculated using the improved Husdon fracture equivalent theory and assigned to the grid representing the background medium. For high-angle or vertical fractures, they are embedded in the equivalent background medium composed of horizontal fractures. The elastic coefficients calculated using the linear sliding related theory are assigned to the corresponding grid to restore their discrete distribution state. This rock physics modeling method takes into account the development of fractures at the same time, which is closer to the actual situation than a single method.

[0070] In a preferred embodiment, Figure 4 As shown, the step S200 of solving the seismic wave field propagation model by the finite difference method to obtain the wave field value may specifically include:

[0071] S210: Using the finite difference method, differential calculation is used to replace the differential operation in the seismic wave field propagation model.

[0072] S220: Solving the seismic wave field propagation model replaced by differential operation to obtain seismic wave field values ​​under different earthquake source excitation conditions.

[0073] Specifically, based on the elastic wave dynamics theory, the seismic wave propagation equations under two initial excitation conditions: explosive source and heavy hammer source.

[0074] First, the oscillating force generated near the earthquake source when the earthquake source is excited is numerically simulated using a function related to time and space to accurately reproduce the force conditions of the medium near the earthquake source, as follows:

[0075] f=Φ(x,y,z,t)=A×r(t)×g(x,x s ) (4)

[0076] Where A is a scalar indicating the intensity of the source when it is excited, r(t) represents the wavelet of the source, and the standard Ricker wavelet is used in the present invention, g(x,x s) represents the Gaussian function related to the distance from the earthquake source. Through the above discretization processing, the spherical disturbance formed in the three-dimensional space when the earthquake source is excited can be expressed as a force density source, with the unit of N / m 3 , so as to achieve the purpose of numerical discrete processing of earthquake sources.

[0077]

[0078] Where F is the main frequency of the wavelet, the starting time of the wavelet is t0=1 / F, and t is the time.

[0079]

[0080] Where X is the current analysis position, s is the center position of the earthquake source, and h is the spatial radius of the Gaussian function. The Gaussian function has a filtering effect. For an appropriate value of h, the numerical dispersion of the seismic wave field forward modeling can be reduced. According to the stress-displacement and stress-strain relationship, the propagation equation of the seismic wave field excited by the explosive earthquake source is as follows:

[0081]

[0082] Where V x ,V y ,V z are the velocity components in the x, y, and z directions respectively, σ xx ,σ yy ,σ zz are the principal stresses in the x, y, and z directions, τ yz ,τ xz ,τ xy are the three shear stress components, ρ is the density of the medium, and Φ is Φ(x, y, z, t).

[0083]

[0084]

[0085]

[0086]

[0087]

[0088]

[0089] Among them, c ij (i, j = 1, ..., 6) is the elastic stiffness coefficient shown in formula (1).

[0090] The propagation equations of the seismic wave field excited by the heavy hammer source are as follows:

[0091]

[0092]

[0093]

[0094]

[0095]

[0096]

[0097]

[0098] Using the finite difference method, the differential calculation of the physical quantity of two adjacent points in space is used instead of the differential operation to obtain the derivative of the physical quantity at the center point.

[0099]

[0100] In the formula, and denote the derivatives of velocity and stress, σ i and σ i+1 represents the stress at two adjacent points, v i and v i+1 Indicates the speed between two adjacent points.

[0101] Solve the seismic wave field values ​​under different source excitation conditions.

[0102] Finally, according to the requirements of the VSP observation system, in the gridded three-dimensional forward geological model, according to the requirements of the detector setting position in the observation system, the seismic wave field values ​​within the recording time period are extracted on the grid at the corresponding position of the three-dimensional forward geological model and output in the commonly used seismic data format.

[0103] The present invention is further described below through a specific example. Step 1: Model the small-scale cracks in the horizontal direction using the improved Husdon crack equivalent model and calculate the corresponding elastic stiffness matrix; use the linear sliding correlation theory to establish the elastic stiffness matrix of high-angle or vertical cracks. The specific model parameters of the embodiment shown in the present invention are shown in Table 1.

[0104] Table 1 Physical properties of the model in the example

[0105]

[0106] The second layer of horizontal small-scale cracks has the following parameters: crack density is 0.05, aspect ratio is 0.001, and filling material is fluid. The crack parameter Z of discretely distributed high-angle or vertical cracks N =Z T =5.6×10 -10 m / pa, the proportion of cracks to grid space is 0.25. According to the method of the present invention, the elastic coefficient matrix of the crack medium is calculated as follows:

[0107] Among them, the elastic coefficients of small-scale cracks in the horizontal direction are shown in Table 2.

[0108] Table 2 Elastic coefficients of small-scale fracture media in horizontal direction

[0109]

[0110]

[0111] The elastic coefficients of discrete cracks at high angles or in the vertical direction are shown in Table 3.

[0112] Table 3 Elastic coefficients of medium with high angle or vertical discrete fractures

[0113]

[0114] Step 2: The small-scale fracture medium in the horizontal direction is used as the background medium of the fractured stratum. The high-angle or vertical fractures are discretely embedded in the background medium composed of the small-scale fractures in the horizontal direction in the form of vertical fractures. Figure 5 The fracture medium forward model is shown in Figure 2. In the second layer of the model schematic, the gray part represents the equivalent background medium composed of small-scale fracture media in the horizontal direction, and the elastic properties are shown in Table 2. The discrete distribution in the vertical direction is high-angle or vertical fractures, and the elastic properties are shown in Table 3.

[0115] Step 3: According to the requirements of the forward algorithm calculation, determine the relevant parameters of the numerical calculation of the seismic wave field, such as time, space step, wavelet main frequency, initial conditions (source) and absorbing boundary conditions, etc. In this embodiment, numerical simulations of seismic wave fields excited by explosive source and heavy hammer source were performed in the multi-scale fracture forward model.

[0116] Step 4: According to the requirements of the VSP observation system, determine the grid of corresponding location points of the detector in the forward model. Figure 6As shown, at least one of the two observation systems of OFFSET VSP and WALK-AWAY VSP can be used. According to the relative spatial position of the source and the detector in the observation system, the seismic wave field values ​​within the recording time period are stored at the corresponding grid points in the gridded three-dimensional forward model in the format of conventional seismic data, so as to obtain the seismic records in the VSP observation system, which is helpful for studying the relationship between the characteristics of the seismic wave field and the physical parameters of the medium. The three-component seismic data under the condition of explosive source excitation and the three-component seismic data under the condition of heavy hammer source excitation are shown as follows: Figure 7 and Figure 8 shown.

[0117] Based on the same principle, this embodiment also discloses a multi-scale fracture three-dimensional geological model VSP observation system. Fig. 9 As shown, in this embodiment, the system includes a model building module 11, a model solving module 12 and a seismic data output module 13.

[0118] Among them, the model building module 11 is used to establish a seismic wave field propagation model according to a preset multi-scale fracture three-dimensional grid forward geological model.

[0119] The model solving module 12 is used to solve the seismic wave field propagation model by the finite difference method to obtain the wave field value.

[0120] The seismic data output module 13 is used to determine the wave field value corresponding to the detector position in the seismic wave field propagation model to output the three-component seismic data of the vertical seismic profile.

[0121] In a preferred embodiment, Fig.10 As shown, the system further comprises a model preset module 10. The model preset module 10 is used to pre-establish the seismic wave field propagation model.

[0122] In a preferred embodiment, the model preset module 10 is specifically used to calculate the elastic coefficient matrix of small-scale horizontal fractures based on the work area fracture parameters using the improved Husdon equivalent fracture theory; calculate the elastic stiffness matrix of high-angle fractures based on a technique combining linear sliding theory with finite difference spatial step size; grid the three-dimensional geological model, and assign the elastic coefficient matrix and the elastic stiffness matrix to the gridded three-dimensional geological model to obtain a seismic wave field propagation model.

[0123] In a preferred embodiment, the model preset module 10 is further used to regard small-scale fractures in the horizontal direction as background media; and embed high-angle or vertical fractures in the background media to form a gridded three-dimensional geological model.

[0124] In a preferred embodiment, the model solving module 12 is specifically used to use the finite difference method to replace the differential operation in the seismic wave field propagation model with differential calculation; solve the seismic wave field propagation model replaced with differential operation to obtain the seismic wave field values ​​under different source excitation conditions.

[0125] Since the principle of solving the problem by this system is similar to that of the above method, the implementation of this system can refer to the implementation of the method and will not be repeated here.

[0126] The systems, 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 a computer device, and specifically, the computer 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.

[0127] In a typical example, the computer 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 method executed by the client as described above is implemented; or, when the processor executes the program, the method executed by the server as described above is implemented.

[0128] Reference below Fig.11 , which shows a schematic diagram of the structure of a computer device 600 suitable for implementing an embodiment of the present application.

[0129] like Fig.11 As shown, the computer 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 part 608 to a random access memory (RAM) 603. In the RAM 603, various programs and data required for the operation of the system 600 are also stored. The CPU 601, the ROM 602, and the RAM 603 are connected to each other via a bus 604. An input / output (I / O) interface 605 is also connected to the bus 604.

[0130] 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 feedback device (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.

[0131] 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 program product, which includes a computer program tangibly contained on a machine-readable medium, and the computer program includes program code for executing the method shown in the flowchart. In such an embodiment, the computer program can be downloaded and installed from a network through the communication part 609, and / or installed from the removable medium 611.

[0132] 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.

[0133] 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.

[0134] 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.

[0135] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0136] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0137] 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.

[0138] 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.

[0139] 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.

[0140] 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.

[0141] 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 multi-scale fracture three-dimensional geological model VSP observation method, characterized in that: include: Establish a seismic wave field propagation model based on the preset multi-scale fracture three-dimensional grid forward geological model; The seismic wave field propagation model is solved by the finite difference method to obtain the wave field value; Determine the wave field value corresponding to the detector position in the seismic wave field propagation model to output the three-component seismic data of the vertical seismic profile; Further comprising the step of pre-establishing the seismic wave field propagation model; The pre-establishing of the seismic wave field propagation model specifically includes: According to the crack parameters in the work area, the elastic coefficient matrix of small-scale horizontal cracks is calculated using the improved Husdon equivalent crack theory. The elastic stiffness matrix of high-angle cracks is calculated based on a technique combining linear sliding theory with finite difference spatial step size; The three-dimensional geological model is gridded, and the elastic coefficient matrix and the elastic stiffness matrix are assigned to the three-dimensional geological model after the gridding process to obtain a seismic wave field propagation model; The method of solving the seismic wave field propagation model by the finite difference method to obtain the wave field value specifically includes: Using the finite difference method, the differential calculation is used to replace the differential operation in the seismic wave field propagation model; Solve the seismic wave field propagation model replaced by differential operation to obtain the seismic wave field values ​​under different source excitation conditions; where: First, the disturbance force generated near the earthquake source when the earthquake source is excited is numerically simulated using a function related to time and space to accurately reproduce the stress conditions of the medium near the earthquake source, as follows: Φ(x,y,z,t)=A×r(t)×g(X,X s ) Among them, Φ(x,y,z,t) is the stress condition of the medium near the earthquake source; A is a scalar indicating the intensity of the earthquake source, r(t) is the sub-wave of the earthquake source, g(X,X s ) represents the Gaussian function related to the distance from the earthquake source; Where F is the main frequency of the sub-wave, the starting time of the sub-wave is t0 = 1 / F, and t is the time; Where X is the current analysis position, X s is the center position of the earthquake source, and h is the spatial radius of the Gaussian function. According to the stress-displacement and stress-strain relationship, the propagation equation of the seismic wave field excited by the explosive earthquake source is as follows: Where V x , V y , V z are the velocity components in the x, y, and z directions, σ xx , σ yy , σ zz are the principal stresses in the x, y, and z directions, τ yz , τ xz , τ xy are the three shear stress components, ρ is the density of the medium, and Φ is Φ(x, y, z, t); Among them, c ij (i,j=1,…,6) is the elastic stiffness coefficient; The propagation equations of the seismic wave field excited by the heavy hammer source are as follows: Using the finite difference method, the differential calculation of the physical quantity of two adjacent points in space is used instead of the differential operation to obtain the derivative of the physical quantity at the central point: In the formula, and denote the derivatives of velocity and stress, σ i and σ i+1 represents the stress at two adjacent points, v i and v i+1 Indicates the speed between two adjacent points.

2. The multi-scale fracture three-dimensional geological model VSP observation method according to claim 1 is characterized in that: The gridding of the three-dimensional geological model specifically includes: Small-scale cracks in the horizontal direction are considered as background media; High-angle or vertical fractures are embedded in the background medium to form a gridded three-dimensional geological model.

3. A multi-scale fracture three-dimensional geological model VSP observation system, characterized in that: include: A model building module is used to establish a seismic wave field propagation model based on a preset multi-scale fracture three-dimensional grid forward geological model; Model solving module, used to solve the seismic wave field propagation model by finite difference method to obtain wave field value; A seismic data output module, used to determine the wave field value corresponding to the detector position in the seismic wave field propagation model to output three-component seismic data of the vertical seismic profile; It further comprises a model preset module for pre-establishing the seismic wave field propagation model; The model preset module is specifically used to calculate the elastic coefficient matrix of small-scale horizontal cracks based on the crack parameters of the work area using the improved Husdon equivalent crack theory; and calculate the elastic stiffness matrix of high-angle cracks based on the technology combining linear sliding theory with finite difference space step size; The three-dimensional geological model is gridded, and the elastic coefficient matrix and the elastic stiffness matrix are assigned to the three-dimensional geological model after the gridding process to obtain a seismic wave field propagation model; Wherein, the model solving module is specifically used for: Using the finite difference method, the differential calculation is used to replace the differential operation in the seismic wave field propagation model; Solve the seismic wave field propagation model replaced by differential operation to obtain the seismic wave field values ​​under different source excitation conditions; where: First, the disturbance force generated near the earthquake source when the earthquake source is excited is numerically simulated using a function related to time and space to accurately reproduce the stress conditions of the medium near the earthquake source, as follows: Φ(x,y,z,t)=A×r(t)×g(X,X s ) Among them, Φ(x,y,z,t) is the stress condition of the medium near the earthquake source; A is a scalar indicating the intensity of the earthquake source, r(t) is the sub-wave of the earthquake source, g(X,X s ) represents the Gaussian function related to the distance from the earthquake source; Where F is the main frequency of the sub-wave, the starting time of the sub-wave is t0 = 1 / F, and t is the time; Where X is the current analysis position, X s is the center position of the earthquake source, and h is the spatial radius of the Gaussian function. According to the stress-displacement and stress-strain relationship, the propagation equation of the seismic wave field excited by the explosive earthquake source is as follows: Where V x ,V y ,V z are the velocity components in the x, y, and z directions respectively, σ xx ,σ yy ,σ zz are the principal stresses in the x, y, and z directions, τ yz ,τ xz ,τ xy are the three shear stress components, ρ is the density of the medium, and Φ is Φ(x, y, z, t); Among them, c ij (i,j=1,…,6) is the elastic stiffness coefficient; The propagation equations of the seismic wave field excited by the heavy hammer source are as follows: Using the finite difference method, the differential calculation of the physical quantity of two adjacent points in space is used instead of the differential operation to obtain the derivative of the physical quantity at the central point: In the formula, and denote the derivatives of velocity and stress, σ i and σ i+1 represents the stress at two adjacent points, v i and v i+1 Indicates the speed between two adjacent points.

4. The multi-scale fracture three-dimensional geological model VSP observation system according to claim 3 is characterized in that: The model preset module is further used to regard small-scale fractures in the horizontal direction as background media; and embed high-angle or vertical fractures in the background media to form a gridded three-dimensional geological model.

5. A computer 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 method according to any one of claims 1 to 2 is implemented.

6. A computer readable medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the method according to any one of claims 1 to 2 is implemented.

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