Method and device for calculating mass exchange coefficient between bedrock and crack in underground reservoir
By using the Green's function integral method in the embedded discrete fracture model, the problem of deviation in the calculation of conductivity between bedrock and fracture in traditional methods is solved, and higher accuracy seepage simulation is achieved, especially significantly improving the calculation accuracy under anisotropic conditions.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-26
- Publication Date
- 2026-04-10
AI Technical Summary
Traditional fracture description methods cannot accurately consider the direction and shape of fractures, resulting in high difficulty in mesh generation and high degree of freedom in solving complex fracture networks. Furthermore, there are deviations in the calculation of conductivity between bedrock and fractures, especially when the bedrock permeability is anisotropic.
An embedded discrete fracture model is adopted. By dividing the underground reservoir into embedded meshes, the connection pairs between the fracture mesh and the bedrock mesh are determined. The conductivity between the bedrock mesh and the fracture mesh is calculated by integrating the Green's function, and the anisotropic effects of pressure response and permeability are accurately considered.
It significantly improves the calculation accuracy of mass exchange between bedrock and fractures, enhances the physical fidelity of seepage simulation, and, especially under anisotropic conditions, reduces the error in conductivity calculation.
Smart Images
Figure CN121834087A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of fracture type underground reservoir seepage flow simulation, and in particular to a method and device for calculating a mass exchange coefficient between bedrock and fractures in an underground reservoir, an electronic device, and a storage medium. BACKGROUND
[0002] Numerical simulation of seepage flow in fracture type underground reservoirs is crucial for the development and utilization of underground resources such as oil and gas reservoirs, geothermal fluids, and hot dry rock. Traditional fracture description methods include equivalent medium models, dual-porosity medium models, and discrete fracture models. The first two methods do not accurately consider the orientation and shape of fractures, and cannot reflect the anisotropy and discontinuity characteristics of fractures. They are only suitable for underground reservoirs with highly developed fractures and strong bedrock permeability. When the reservoir permeability is dominated by fractures, the simulation accuracy is low. In comparison, the discrete fracture model explicitly describes fractures, which can accurately describe the orientation and shape of fractures and has higher simulation accuracy. However, because the fracture surface is used as a constraint surface in grid partitioning, a large number of unstructured grids are required for the entire calculation area, which makes grid partitioning difficult and increases the degree of freedom in solving, limiting its application in practical engineering. On the other hand, the embedded fracture model is a more advanced fracture description method proposed in recent years. It also accurately considers the orientation and shape of fractures, but the internal bedrock and fracture regions are divided using independent grids, avoiding the use of unstructured grids and improving computational efficiency, thus attracting widespread attention and research.
[0003] In the embedded discrete fracture model, because the bedrock and fractures are independently divided into grids, the mass exchange between the bedrock and fracture grids cannot be directly calculated by the interface flux, but is introduced by adding a source term in the control equation. The calculation method of this source term is the pressure difference between the bedrock and fracture grids multiplied by the corresponding conductivity. Therefore, the accuracy of the conductivity calculation between the bedrock and fractures directly affects the overall accuracy and reliability of the numerical simulation solution. In the classical embedded discrete fracture model, the conductivity between the bedrock and fractures is derived based on the assumption that the pressure distribution within the bedrock is linearly related to the distance from the bedrock to the fracture. However, in actual problems, the pressure gradient is larger near the fracture, and when the bedrock permeability is anisotropic, the pressure gradient along the fracture also affects the mass exchange, making the deviation caused by the classical conductivity calculation method between the bedrock and fractures even larger. SUMMARY
[0004] Therefore, it is necessary to provide a method and device for calculating a mass exchange coefficient between bedrock and fractures in an underground reservoir to solve the problem that the pressure gradient along the fracture affects the mass exchange when the bedrock permeability is anisotropic, making the deviation caused by the classical conductivity calculation method between the bedrock and fractures even larger.
[0005] To solve the above problems, the present application provides a method for calculating the mass exchange coefficient between the bedrock and the fractures in the underground reservoir, comprising: Carrying out embedded grid division on the bedrock region and the fracture region in the underground reservoir, and determining the connection pair between the fracture grid and the bedrock grid; Based on the permeability of the bedrock grid corresponding to the connection pair, determining the Green's function in the principal axis coordinate system of the bedrock grid permeability; Taking the source term coordinate in the Green's function as a variable, integrating the Green's function along the fracture grid belonging to the same connection pair, and determining the pressure response function; Based on the pressure response function, determining the conductivity between the bedrock grid and the fracture grid corresponding to the connection pair.
[0006] In a possible implementation, the step of determining the Green's function in the principal axis coordinate system of the bedrock grid permeability based on the permeability of the bedrock grid corresponding to the connection pair comprises: Based on the value of the permeability in the Cartesian coordinate system, determining the angle between the bedrock grid permeability principal axis and the coordinate axis in the Cartesian coordinate system, and the value of the permeability in the bedrock grid permeability principal axis coordinate system; Based on the coordinate conversion relationship between the bedrock grid permeability principal axis coordinate system and the Cartesian coordinate system, converting the pressure Poisson equation in the Cartesian coordinate system into the pressure Poisson equation in the bedrock grid permeability principal axis coordinate system; Integrating the pressure Poisson equation in the bedrock grid permeability principal axis coordinate system to obtain the Green's function.
[0007] In a possible implementation, the step of determining the conductivity between the bedrock grid and the fracture grid corresponding to the connection pair based on the pressure response function comprises: Carrying out volume integration of the pressure response function in the bedrock grid region and dividing by the bedrock grid volume to obtain the average pressure response of the bedrock grid; Carrying out line integration of the pressure response function along the fracture segment surface and dividing by the fracture segment length to obtain the average pressure response of the fracture segment surface; Based on the average pressure response of the bedrock grid and the average pressure response of the fracture segment surface, obtaining the conductivity between the bedrock grid and the fracture grid corresponding to the connection pair.
[0008] In a possible implementation, the step of obtaining the conductivity between the bedrock grid and the fracture grid corresponding to the connection pair based on the average pressure response of the bedrock grid and the average pressure response of the fracture segment surface comprises: obtaining a pressure difference between the matrix grid and the fracture grid based on the average pressure response of the matrix grid and the average pressure response of the fracture segment surface; obtaining the conductivity based on the volume flow rate from the matrix grid to the fracture grid and the pressure difference.
[0009] In a possible implementation, the method further includes: performing embedded grid division on the matrix region and the fracture region to determine coverage information of the fracture grid on the matrix grid; determining the connection pair based on the coverage information.
[0010] In a possible implementation, the method further includes: obtaining a seepage field of the entire region including the matrix region and the fracture region based on the conductivity and a discrete equation of the embedded discrete fracture model; and evaluating the calculation accuracy of the conductivity based on the seepage field.
[0011] The application further provides a device for calculating a mass exchange coefficient between a matrix and a fracture in a subsurface reservoir, including: a first obtaining module configured to perform embedded grid division on a matrix region and a fracture region in a subsurface reservoir to determine a connection pair between a fracture grid and a matrix grid; a second obtaining module configured to determine a Green's function in a permeability principal coordinate system of the matrix grid based on a permeability of the matrix grid corresponding to the connection pair; a third obtaining module configured to determine a pressure response function by taking a source term coordinate in the Green's function as a variable and integrating the Green's function along the fracture grid belonging to the same connection pair; a fourth obtaining module configured to determine a conductivity between the matrix grid and the fracture grid corresponding to the connection pair based on the pressure response function.
[0012] In a possible implementation, the device further includes: an evaluating module configured to obtain a seepage field of the entire region including the matrix region and the fracture region based on the conductivity and a discrete equation of the embedded discrete fracture model; and evaluate the accuracy of the conductivity based on the seepage field.
[0013] The application further provides an electronic device including a memory and a processor, wherein the memory is configured to store a program; The processor, coupled to the memory, is used to execute the program stored in the memory to implement the steps in the method for calculating the mass exchange coefficient between bedrock and fractures in underground reservoirs as described in any of the above implementations.
[0014] The present invention also provides a computer-readable storage medium for storing a computer-readable program or instruction, which, when executed by a processor, can implement the steps in the method for calculating the mass exchange coefficient between bedrock and fractures in underground reservoirs as described in any of the above implementations.
[0015] The beneficial effects of this invention are as follows: The method for calculating the mass exchange coefficient between bedrock and fractures in underground reservoirs provided by this invention no longer uses the classical method with large errors to calculate conductivity. Instead, it uses an accurate analytical solution of the Green's function to replace the simplified linear pressure distribution relationship for calculating conductivity. Utilizing the Green's function's inherent inclusion of nonlinear pressure distribution characteristics, the calculation accuracy for simulating isotropic / anisotropic bedrock-fracture flow exchange is significantly improved. By operating in the principal axis coordinate system, the influence of matrix permeability anisotropy can be accurately characterized. Through the integration process, the geometric morphology (length, orientation) of fractures and their relative positional relationship with the matrix mesh are accurately considered. This fundamentally improves the physical fidelity of transient flow and anisotropic descriptions, significantly enhancing the calculation accuracy of mass exchange between bedrock and fractures in embedded discrete fracture model seepage simulations. Attached Figure Description
[0016] Figure 1 A flowchart illustrating an embodiment of the method for calculating the mass exchange coefficient between bedrock and fractures in underground reservoirs provided by the present invention. Figure 2 Mesh partitioning diagram of the embedded discrete crack model provided by this invention; Figure 3 This is a schematic diagram of crack coordinates and computational region mesh division in Case 1 and Case 2 provided by the present invention; Figure 4 This is a schematic diagram of crack coordinates and computational region mesh division in Case 1 and Case 2 provided by the present invention; Figure 5 A schematic diagram illustrating the relative error distribution between the Green's integral method and the classical calculation method provided by this invention; Figure 6 A schematic diagram comparing the pressure profiles of the numerical solution and the reference solution of the Green's integral method in Case 2 provided by the present invention; Figure 7 A schematic diagram of the relative error distribution between the Green's integral method and the classical calculation method in Case 2 provided by the present invention; Figure 8A schematic diagram of an embodiment of the mass exchange coefficient calculation device between bedrock and fractures in underground reservoirs provided by the present invention; Figure 9 A schematic diagram of the structure of an embodiment of the electronic device provided by the present invention. Detailed Implementation
[0017] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.
[0018] The purpose of this invention is to improve the calculation accuracy of mass exchange between bedrock and fractures in seepage simulation of embedded discrete fracture models. It provides a new method for calculating the conductivity between bedrock and fractures based on Green's integral function (hereinafter referred to as Green's integral method), which is implemented as follows.
[0019] like Figure 1 As shown, a specific embodiment of the present invention discloses a method for calculating the mass exchange coefficient between bedrock and fractures in an underground reservoir, including steps S101, S102, S103 and S104.
[0020] Step S101 involves embedding meshes into the bedrock and fracture regions of the underground reservoir and determining the connection pairs between the fracture meshes and the bedrock meshes. Step S102 determines the Green's element function in the principal axis coordinate system of bedrock grid permeability based on the permeability of the bedrock grid corresponding to the connection pair; Step S103: Using the source term coordinates in the Green's function as variables, integrate the Green's function along the crack mesh belonging to the same connection pair to determine the pressure response function; Step S104 determines the conductivity between the bedrock grid and the fracture grid corresponding to the connection pair based on the pressure response function.
[0021] During implementation, embedded meshes are used to divide the bedrock and fracture regions in the underground reservoir to determine the connection pairs between the fracture mesh and the bedrock mesh.
[0022] In this step, during embedded mesh generation, the bedrock and fracture regions use independent meshes. For example, in a two-dimensional simulation, the bedrock region uses a rectangular structured mesh, while the fracture region uses a one-dimensional mesh. The mesh faces are located at the intersections of the fracture lines and the bedrock mesh. Figure 2 As shown.
[0023] In one possible implementation, step S101 may include: Embedded meshes are generated for the bedrock region and the fracture region to determine the coverage information of the fracture mesh on the bedrock mesh. Based on the coverage information, the connection pair is determined.
[0024] In this step, by combining the acquired physical properties and geometric information of the bedrock and fractures in the underground reservoir, the overlay information of the fracture mesh on the bedrock mesh is further obtained, and the connection pairs between the fracture mesh and the bedrock mesh are determined accordingly, for example... Figure 2 The connection pairs in the local region shown are m3 and f1, m2 and f2, m5 and f3, m8 and f4, and m7 and f5.
[0025] It should be noted that the physical properties of bedrock and fractures include permeability, fluid viscosity, and fracture pore size, while geometric information includes the position and orientation of the fracture relative to the bedrock.
[0026] The purpose of this invention is to solve for the conductivity of each connection pair: (1) In the formula, The volumetric flow rate from the bedrock grid to the fracture grid; It is the pressure difference between the bedrock grid and the fracture grid; The conductivity of the connection pair; It is a bedrock grid. It is a cracked mesh.
[0027] For a connection pair of a fracture grid and a bedrock grid, the direction of the principal axis of bedrock permeability is determined based on the permeability of the bedrock grid. Coordinate transformation is then performed to obtain the pressure Poisson equation and Green's function in the coordinate system of the principal axis of permeability of the bedrock grid.
[0028] In one possible implementation, step S102 may include: Based on the permeability value in the Cartesian coordinate system, determine the angle between the principal axis of permeability of the bedrock grid and the coordinate axis in the Cartesian coordinate system, as well as the value of permeability in the principal axis coordinate system of the bedrock grid. Based on the coordinate transformation relationship between the principal axis coordinate system of the bedrock grid permeability and the Cartesian coordinate system, the pressure Poisson equation in the Cartesian coordinate system is transformed into the pressure Poisson equation in the principal axis coordinate system of the bedrock grid permeability. The Green's function is obtained by integrating the pressure Poisson equation in the principal coordinate system of the bedrock grid permeability.
[0029] To make the formula more concise and clear, the following explanation uses a two-dimensional fractured reservoir flow simulation as an example. This method is also applicable to three-dimensional fractured reservoir simulation.
[0030] During implementation, it is considered that there is anisotropic permeability tensor in the corresponding bedrock grid of the connection pair, which has the following relationship with the permeability in the principal axis direction: (2) In the formula, For penetration rate; subscript and Values in the original coordinate system (i.e., Cartesian coordinate system); subscript and This represents the value of permeability in the principal axis coordinate system; for Axis-directed bedrock grid permeability principal axis ( The angle between the axes is positive when counterclockwise.
[0031] The pressure Poisson equation in the original coordinate system is: (3) In the formula, Bedrock pressure; For source terms; This refers to the fluid dynamic viscosity.
[0032] Coordinate transformation relationship between the principal axis coordinate system of bedrock grid permeability and the Cartesian coordinate system. Substitute into equation (3) and introduce and Stretch the permeability principal axis coordinate system, and From this, we can obtain the pressure Poisson equation in the principal axis coordinate system of bedrock grid permeability: (4) Integrating formula (4) indefinitely yields the Green's function. for: (5) Its physical meaning is the source term coordinate ( The unit source term at ) (i.e. )right Pressure fluctuations generated at the location.
[0033] Using the source term coordinates in the Green's function as variables, the Green's function obtained in the above steps is integrated along the crack mesh belonging to the same connection pair to obtain the pressure response function. Its physical meaning is the pressure influence of the mass exchange between the crack segment covered by the bedrock mesh and the bedrock along the line on a certain point in the bedrock region.
[0034] Assumption Source terms arising from fracture grids located on the same connectivity pair and from mass exchange between fractures and bedrock. The pressure response function is obtained by integrating the Green's function from the above steps along the crack segment, which is uniformly distributed along the crack segment. for: (6) In the formula, Represents the crack segment; the integral variable is and ; This represents the function obtained after the Green's element line integral. The physical meaning of this expression is the pressure effect on a point in the bedrock region caused by the mass exchange between the fracture segment covered by the bedrock mesh and the bedrock along the line. Assume the fracture segment is a straight line, and its coordinates satisfy the expression... (in, and Let these be two constants describing the distribution of crack segments. Therefore, the analytical expression for the Green's element line integral function is: (7) In the formula, and Let be the integral endpoint value of the crack segment. Equations (6) and (7) show that the pressure response function is in spatial coordinates. The function.
[0035] In one possible implementation, step S104 may include: The pressure response function is integrally divided by the bedrock grid volume in the bedrock grid region to obtain the average pressure response of the bedrock grid. The average pressure response of the crack segment surface is obtained by integrating the pressure response function along the crack segment surface and dividing it by the crack segment length. Based on the average pressure response of the bedrock grid and the average pressure response of the fracture segment surface, the conductivity between the bedrock grid and the fracture grid corresponding to the connection pair is obtained.
[0036] During implementation, the pressure response function in the above steps is integrally divided by the bedrock grid volume in the bedrock grid region to obtain the average pressure response of the bedrock grid; the pressure response function is integrally divided by the fracture length along the fracture segment surface to obtain the average pressure response of the fracture segment surface. Integrating equation (6) by volume over the bedrock grid region and dividing by the bedrock grid volume yields the average pressure response of the bedrock grid: (8) In the formula, It is the average pressure response in the bedrock grid region; This represents the volume of the bedrock grid region.
[0037] Assume the diameter of the fracture mesh in the permeability principal axis coordinate system is Then the expression for the surface of the crack segment is: Integrating equation (6) along the surface of the crack segment and dividing by the crack segment length yields the average pressure response at the surface of the crack segment: (9) In the formula, It is the average pressure response on the surface of the crack segment.
[0038] In one possible implementation, the above steps, based on the average pressure response of the bedrock grid and the average pressure response of the fracture segment surface, determine the conductivity between the bedrock grid and the fracture grid corresponding to the connection pair, including: The pressure difference between the bedrock grid and the fracture grid is obtained based on the average pressure response of the bedrock grid and the average pressure response of the fracture segment surface. The conductivity is obtained based on the volumetric flow rate from the bedrock grid to the fracture grid and the pressure difference.
[0039] During implementation, based on the average pressure response of the bedrock mesh and fracture surface in the above steps, the conductivity between the bedrock and fracture of the connection pair is calculated, specifically: The pressure difference between the bedrock grid and the fracture grid is obtained based on the average pressure response of the bedrock grid and the average pressure response of the fracture segment surface. : The volumetric flow rate between the bedrock mesh and the fracture mesh is... : Substituting these two terms into equation (1) will eliminate the source term. And the conductivity between the bedrock and the fracture was obtained: (10) For each connection pair, the above calculation method can be used to obtain the conductivity of all connection pairs between the bedrock mesh and the fracture mesh.
[0040] In one possible implementation, the above method may further include: Based on the conductivity and the discrete equations of the embedded discrete fracture model, the seepage field of the entire region, including the bedrock region and the fracture region, is obtained. The accuracy of the conductivity calculation is evaluated based on the seepage field.
[0041] During implementation, the conductivity between the bedrock mesh and the fracture mesh of each connection pair is calculated and substituted into the discrete equation of the embedded discrete fracture model to solve the seepage field of the entire region, including the bedrock region and the fracture region.
[0042] For each connection pair, repeat the above steps to calculate the conductivity between the bedrock mesh and the fracture mesh, and substitute it into the governing equations of the embedded discrete fracture model. For example, in a two-dimensional steady-state simulation, it would be: (11) In the formula, For crack pressure; The permeability within the crack; The crack axis; The volumetric flow rate generated by the intersection of cracks is then substituted into the equation to obtain the seepage field for the entire region. It is worth noting that the conductivity calculation is part of the pre-processing stage of the simulation and only needs to be performed once before the simulation begins.
[0043] The calculated seepage field is compared with the seepage field obtained by the classical method for calculating the conductivity between bedrock and fractures. The relative errors of the two methods are statistically analyzed to evaluate the calculation accuracy of the calculation method provided by this invention.
[0044] Taking the following two-dimensional fractured reservoir as an example, it is shown that the method for calculating the conductivity between bedrock and fractures proposed in this invention has higher accuracy than the classical calculation method.
[0045] Case 1: The calculation area is 10m × 10m, and the crack permeability is... D, the bedrock permeability is isotropic, with a value of 1D, the fluid viscosity. The crack diameter is 1 cm, and the coordinates of the crack location are as follows: Figure 3 As shown, the bedrock region is divided using a 50×50 grid. A full-scale solution with a 1000×1000 grid is used as the reference solution. Numerical solutions are obtained using both the Green's integral method described in this invention and the classical method for calculating the conductivity between bedrock and fractures. The relative errors of the two methods are then statistically analyzed. The expression for the classical method for calculating the conductivity between bedrock and fractures is: (12) In the formula, is the unit vector of the vertical crack; The equivalent distance between the crack and the bedrock in the bedrock grid is expressed as follows: , Figure 4 A comparison is given between the pressure profile calculated using the Green's integral method of this invention and the reference solution. Figure 5 The relative error distributions of two conductivity calculation methods are presented. The left figure shows the Green's integral method, and the right figure shows the classical calculation method. It can be seen that the region with the largest relative error in the Green's integral method of this invention is smaller. Table 1 lists the maximum and average relative errors in the calculation regions, showing that the Green's integral method of this invention has significantly smaller errors than the classical calculation method.
[0046] Table 1: Relative Error in Case 1
[0047] Case 2: The bedrock permeability is anisotropic, with a value of Other parameters are the same as in Case 1. Figure 6 A comparison is given between the pressure profile calculated using the Green's integral method of this invention and the reference solution. Figure 7 The relative error distributions of the two methods are shown. The left figure represents the Green's integral method, and the right figure represents the classical calculation method. Table 2 shows the relative errors of the two methods. It can be seen that the Green's integral method in this invention has higher accuracy than the classical calculation method.
[0048] Table 2: Relative Error in Case 2
[0049] Compared to existing technologies, the method for calculating the mass exchange coefficient between bedrock and fractures in underground reservoirs provided in this embodiment no longer uses the classical method with large errors to calculate conductivity. Instead, it uses an accurate analytical solution of the Green's function to replace the simplified linear pressure distribution relationship for calculating conductivity. Utilizing the Green's function's inherent inclusion of nonlinear pressure distribution characteristics, the calculation accuracy for simulating isotropic / anisotropic bedrock-fracture flow exchange is significantly improved. By operating in the principal axis coordinate system, the influence of matrix permeability anisotropy can be accurately characterized. Through the integration process, the geometry (length, orientation) of fractures and their relative positional relationship with the matrix mesh are precisely considered. This fundamentally improves the physical fidelity of transient flow and anisotropic descriptions, significantly enhancing the calculation accuracy of mass exchange between bedrock and fractures in embedded discrete fracture model seepage simulations.
[0050] like Figure 8 As shown, the present invention also provides a device 80 for calculating the mass exchange coefficient between bedrock and fractures in underground reservoirs, comprising: The first acquisition module 801 is used to perform embedded mesh division on the bedrock region and fracture region in the underground reservoir, and determine the connection pairs between the fracture mesh and the bedrock mesh. The second acquisition module 802 is used to determine the Green's element function in the principal axis coordinate system of bedrock grid permeability based on the permeability of the bedrock grid corresponding to the connection pair. The third acquisition module 803 is used to integrate the Green's function along the crack mesh belonging to the same connection pair, using the source term coordinates in the Green's function as variables, to determine the pressure response function; The fourth acquisition module 804 is used to determine the conductivity between the bedrock grid and the fracture grid corresponding to the connection pair based on the pressure response function.
[0051] In one possible implementation, the above-mentioned apparatus may further include: Evaluation module 805 is used to obtain the seepage field of the entire region, including the bedrock region and the fracture region, based on the conductivity and the discrete equations of the embedded discrete fracture model; and, The accuracy of the conductivity is evaluated based on the seepage field.
[0052] Compared to existing technologies, the mass exchange coefficient calculation device for bedrock and fractures in underground reservoirs provided by this invention no longer uses the classical method with large errors to calculate conductivity. Instead, it uses an accurate analytical solution of the Green's function to replace the simplified linear pressure distribution relationship for calculating conductivity. Utilizing the Green's function's inherent inclusion of nonlinear pressure distribution characteristics, the calculation accuracy for simulating isotropic / anisotropic bedrock-fracture flow exchange is significantly improved. By operating in the principal axis coordinate system, the influence of matrix permeability anisotropy can be accurately characterized. Through the integration process, the geometry (length, orientation) of fractures and their relative positional relationship with the matrix mesh are precisely considered. This fundamentally improves the physical fidelity of transient flow and anisotropic descriptions, significantly enhancing the calculation accuracy of bedrock-fracture mass exchange in embedded discrete fracture model seepage simulations.
[0053] like Figure 9 As shown, the present invention also provides an electronic device. This electronic device 90 includes a processor 910, a memory 920, and a display 930. Figure 9 Only some components of the electronic device 90 are shown, but it should be understood that it is not required to implement all of the components shown, and more or fewer components may be implemented instead.
[0054] In some embodiments, processor 910 may be a central processing unit (CPU), microprocessor, or other data processing chip, used to run program code stored in memory 920 or process data, such as the method for calculating the mass exchange coefficient between bedrock and fractures in underground reservoirs in this invention.
[0055] In some embodiments, processor 910 may be a single server or a group of servers. The server group may be centralized or distributed. In some embodiments, processor 910 may be local or remote. In some embodiments, processor 910 may be implemented on a cloud platform. In one embodiment, the cloud platform may include a private cloud, public cloud, hybrid cloud, community cloud, distributed cloud, internal cloud, multi-cloud, etc., or any combination thereof.
[0056] In some embodiments, memory 920 may be an internal storage unit of an electronic device, such as a hard disk or memory of the electronic device 90. In other embodiments, memory 920 may also be an external storage device of the electronic device 90, such as a plug-in hard disk, smart media card (SMC), secure digital (SD) card, flash card, etc., provided on the electronic device 90.
[0057] Furthermore, the memory 920 may include both internal storage units and external storage devices of the electronic device 90. The memory 920 is used to store application software and various types of data installed on the electronic device 90.
[0058] In some embodiments, display 930 may be an LED display, a liquid crystal display, a touch-sensitive liquid crystal display, or an OLED (Organic Light Emitting Diode) touchscreen. Display 930 is used to display information from electronic device 90 and to display a visual user interface. Components 910 to 930 of electronic device 90 communicate with each other via a system bus.
[0059] In one embodiment, when the processor 910 executes the program for calculating the mass exchange coefficient between bedrock and fractures in the underground reservoir stored in the memory 920, the following steps can be implemented: Embedded meshes were created for the bedrock and fracture regions in the underground reservoir, and the connection pairs between the fracture mesh and the bedrock mesh were determined. Based on the permeability of the bedrock grid corresponding to the connection pair, determine the Green's element function in the principal axis coordinate system of bedrock grid permeability; Using the source term coordinates in the Green's function as variables, the Green's function is integrated along the crack mesh belonging to the same connection pair to determine the pressure response function; Based on the pressure response function, the conductivity between the bedrock grid and the fracture grid corresponding to the connection pair is determined.
[0060] It should be understood that when the processor 910 executes the program for calculating the mass exchange coefficient between bedrock and fractures in the underground reservoir stored in the memory 920, in addition to the functions mentioned above, it can also perform other functions, as detailed in the description of the corresponding method embodiments above.
[0061] Furthermore, the embodiments of the present invention do not specifically limit the type of electronic device 90 mentioned. Electronic device 90 can be a mobile phone, tablet computer, personal digital assistant (PDA), wearable device, laptop computer, or other portable electronic device. Exemplary embodiments of portable electronic devices include, but are not limited to, portable electronic devices running iOS, Android, Microsoft, or other operating systems. The aforementioned portable electronic device can also be other portable electronic devices, such as a laptop computer with a touch-sensitive surface (e.g., a touch panel). It should also be understood that in some other embodiments of the present invention, electronic device 90 may not be a portable electronic device, but rather a desktop computer with a touch-sensitive surface (e.g., a touch panel).
[0062] Accordingly, this application also provides a computer-readable storage medium for storing a computer-readable program or instruction. When the program or instruction is executed by a processor, it can implement the steps or functions of the data method provided in the above-described method embodiments.
[0063] Those skilled in the art will understand that all or part of the processes of the methods described in the above embodiments can be implemented by a computer program instructing related hardware, and the computer program can be stored in a computer-readable storage medium. The computer-readable storage medium may be a disk, optical disk, read-only memory, or random access memory, etc.
[0064] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.
Claims
1. A method for calculating a mass exchange coefficient between a matrix and a fracture in a subterranean reservoir, characterized in that, The method comprises the following steps: performing embedded grid division on the matrix region and the fracture region in the underground reservoir to determine a connection pair between the fracture grid and the matrix grid; determining a Green's function in a principal axis coordinate system of the matrix grid permeability based on the permeability of the matrix grid corresponding to the connection pair; taking the source term coordinate in the Green's function as a variable, integrating the Green's function along the fracture grid belonging to the same connection pair to determine a pressure response function; determining the conductivity between the matrix grid and the fracture grid corresponding to the connection pair based on the pressure response function.
2. The method for calculating the mass exchange coefficient between the matrix and the fractures in a subterranean reservoir according to claim 1, characterized in that, The step of determining the Green's function in the principal axis coordinate system of the matrix grid permeability based on the permeability of the matrix grid corresponding to the connection pair comprises the following steps: determining the angle between the matrix grid permeability principal axis and the coordinate axis in the Cartesian coordinate system and the value of the permeability in the principal axis coordinate system of the matrix grid permeability based on the value of the permeability in the Cartesian coordinate system; converting the pressure Poisson equation in the Cartesian coordinate system into the pressure Poisson equation in the principal axis coordinate system of the matrix grid permeability based on the coordinate conversion relationship between the principal axis coordinate system of the matrix grid permeability and the Cartesian coordinate system; integrating the pressure Poisson equation in the principal axis coordinate system of the matrix grid permeability to obtain the Green's function.
3. The method for calculating a mass exchange coefficient between a matrix and a fracture in a subsurface reservoir according to claim 1, characterized in that, The step of determining the conductivity between the matrix grid and the fracture grid corresponding to the connection pair based on the pressure response function comprises the following steps: performing volume integration on the pressure response function in the matrix grid region and dividing the volume integration result by the volume of the matrix grid to obtain the average pressure response of the matrix grid; performing line integration on the pressure response function along the fracture segment surface and dividing the line integration result by the length of the fracture segment to obtain the average pressure response of the fracture segment surface; obtaining the conductivity between the matrix grid and the fracture grid corresponding to the connection pair based on the average pressure response of the matrix grid and the average pressure response of the fracture segment surface.
4. The method for calculating a mass exchange coefficient between a matrix and a fracture in a subsurface reservoir according to claim 3, characterized in that, The step of obtaining the conductivity between the matrix grid and the fracture grid corresponding to the connection pair based on the average pressure response of the matrix grid and the average pressure response of the fracture segment surface comprises the following steps: obtaining the pressure difference between the matrix grid and the fracture grid based on the average pressure response of the matrix grid and the average pressure response of the fracture segment surface; obtaining the conductivity based on the volume flow rate of the matrix grid flowing to the fracture grid and the pressure difference.
5. The method for calculating a mass exchange coefficient between a matrix and a fracture in a subsurface reservoir according to claim 1, characterized in that, The step of performing embedded grid division on the matrix region and the fracture region in the underground reservoir to determine a connection pair between the fracture grid and the matrix grid comprises the following steps: performing embedded grid division on the matrix region and the fracture region to determine the coverage information of the fracture grid on the matrix grid; determining the connection pair based on the coverage information.
6. The method for calculating the mass exchange coefficient between matrix and fractures in a subterranean reservoir according to any one of claims 1 to 5, characterized in that, The method further comprises the following steps: obtaining the seepage field of the entire region including the matrix region and the fracture region based on the conductivity and the discrete equation of the embedded discrete fracture model; evaluating the calculation accuracy of the conductivity based on the seepage field.
7. A device for calculating the mass exchange coefficient between bedrock and fractures in an underground reservoir, characterized in that, The method comprises the following steps: a first obtaining module is configured to perform embedded grid division on the matrix region and the fracture region in the underground reservoir to determine a connection pair between the fracture grid and the matrix grid; The second obtaining module is configured to determine a Green's function in a principal axis coordinate system of a matrix grid permeability based on the matrix grid permeability corresponding to the connection pair; The third obtaining module is configured to determine a pressure response function by integrating the Green's function along the crack grid belonging to the same connection pair with the source term coordinate in the Green's function as a variable; The fourth obtaining module is configured to determine the conductivity between the matrix grid and the crack grid corresponding to the connection pair based on the pressure response function.
8. The apparatus according to claim 7, wherein The device further comprises: The evaluation module is configured to obtain a seepage field of the entire region including the matrix region and the crack region based on the conductivity and a discrete equation of the embedded discrete crack model; and The accuracy of the conductivity is evaluated based on the seepage field.
9. An electronic device, comprising: The device comprises: The memory is configured to store a program; The processor is coupled to the memory and is configured to execute the program stored in the memory to implement the steps of the method for calculating the mass exchange coefficient between the matrix and the crack in the underground reservoir according to any one of claims 1 to 6.
10. A computer-readable storage medium, characterized in that, The device is configured to store a computer-readable program or instruction, and the program or instruction is executed by the processor to implement the steps of the method for calculating the mass exchange coefficient between the matrix and the crack in the underground reservoir according to any one of claims 1 to 6.