Fractured reservoir numerical simulation method, device and equipment and storage medium

Abstract

The invention provides a fractured reservoir numerical simulation method, device and equipment and a storage medium, and relates to the technical field of oil and gas field exploitation. The method comprises the following steps: acquiring oil-gas exploration parameters of a preset area; wherein the oil-gas exploration parameters comprise at least one of reservoir parameters, fracture parameters and fluid parameters; determining a transient correction factor according to the reservoir parameters and the fluid parameters; wherein the transient correction factor represents the transient flow capacity between the underground crack and the underground matrix, and the underground matrix represents the underground geological structure; determining a transient parameter according to the transient correction factor and the oil-gas exploration parameter; wherein the transient parameters represent attributes of oil and gas reservoirs in the preset area at the current moment, and the transient parameters are used for oil and gas output value prediction. According to the method, the accuracy of numerical simulation is improved through the transient correction factor.

Description

Technical Field

[0001] The present application relates to the technical field of oil and gas field exploitation, and in particular to a method, device, equipment and storage medium for numerical simulation of fractured reservoirs. Background Art

[0002] Oil and gas reservoirs are important storage places for oil and gas resources. The development process of oil and gas reservoirs involves complex geological structures and seepage characteristics. The existence of natural and artificial fractures makes the fluid flow process more complicated. Fractures not only affect the flow path of oil and gas, but also largely determine the recovery efficiency of oil and gas.

[0003] With the exploitation of conventional resources, global oil and gas resources are decreasing, and unconventional resources are gradually becoming mainstream. However, compared with conventional reservoirs, most unconventional reservoirs have natural fractures and belong to fractured reservoirs. The existing technology is used to numerically simulate the properties of fractured oil and gas reservoirs, which is inaccurate and has large errors. Therefore, it is urgent to accurately simulate the properties of fractured oil and gas reservoirs. Summary of the invention

[0004] The present application provides a fractured reservoir numerical simulation method, device, equipment and storage medium for accurately numerically simulating the property characteristics of fractured oil and gas reservoirs.

[0005] On the one hand, the present application provides a method for numerical simulation of fractured reservoirs, the method comprising:

[0006] Obtaining oil and gas exploration parameters of a preset area; wherein the oil and gas exploration parameters include at least one of a reservoir parameter, a fracture parameter, and a fluid parameter;

[0007] Determine a transient correction factor according to reservoir parameters and fluid parameters; wherein the transient correction factor represents the transient flow capacity between underground fractures and underground matrix, and the underground matrix represents the underground geological structure;

[0008] According to the transient correction factor and the oil and gas exploration parameters, the transient parameters are determined; wherein the transient parameters characterize the properties of the oil and gas reservoirs in the preset area at the current moment, and the transient parameters are used to predict the oil and gas production value.

[0009] Optionally, the fluid parameters include fluid viscosity, volume coefficient, and fluid matrix relative permeability; the reservoir parameters include matrix permeability and matrix porosity; and the transient correction factor is determined according to the reservoir parameters and the fluid parameters, including:

[0010] A transient correction factor is obtained according to fluid viscosity, volume coefficient, matrix permeability, preset matrix grid length, preset compressibility, fluid matrix relative permeability, matrix porosity, and simulation time; wherein the simulation time represents the length of time from the moment when the oil and gas exploration parameters are obtained to the current moment.

[0011] Optionally, the method further comprises:

[0012] If the simulation time is within the preset time range, a transient correction factor is obtained according to the fluid viscosity, the volume coefficient, the matrix permeability, the preset matrix grid length, the preset compressibility coefficient, the fluid matrix relative permeability, the matrix porosity, and the simulation time;

[0013] If the simulation time is not within the preset time range, the transient correction factor is determined to be a preset value.

[0014] Optionally, the transient parameters are determined according to the transient correction factor and the oil and gas exploration parameters, including:

[0015] According to the reservoir parameters and the fracture parameters, the conductivity between the preset matrix grid and the preset fracture grid is obtained; wherein the matrix grid represents the underground matrix structure, the fracture grid represents the distribution of the underground fractures, and the conductivity represents the characteristics of the underground soil;

[0016] According to the conductivity, transient correction factor, and oil and gas exploration parameters, the transient parameters of the matrix grid and the transient parameters of the fracture grid are obtained.

[0017] Optionally, according to the conductivity, the transient correction factor, and the oil and gas exploration parameters, the transient parameters of the matrix grid and the transient parameters of the fracture grid are obtained, including:

[0018] Obtaining a transient parameter of the matrix grid at a preset historical moment as a first historical parameter; and obtaining a transient parameter of the fracture grid at a preset historical moment as a second historical parameter;

[0019] Obtaining a transient parameter of the matrix grid at the current moment according to the conductivity, the reservoir parameter, the fluid parameter, the transient correction factor, and the first historical parameter; wherein the transient parameter of the matrix grid at the current moment includes at least one of a transient exchange velocity between the matrix grid and the fracture grid, a saturation of the matrix grid, and a pressure of the matrix grid;

[0020] According to the conductivity, the reservoir parameter, the fluid parameter, the fracture parameter, the transient correction factor, and the second historical parameter, a transient parameter of the fracture grid at the current moment is obtained; wherein the transient parameter of the fracture grid at the current moment includes at least one of a fluid exchange rate between the matrix grid and the fracture grid, a saturation of the fracture grid, and a pressure of the fracture grid.

[0021] Optionally, it also includes:

[0022] Acquire well parameters of a preset area, and acquire a preset skin factor and a preset wellbore reservoir coefficient; wherein the well parameters represent the mining information of the wellbore in the preset area, the preset skin factor represents the degree of formation damage in the preset area, and the preset wellbore reservoir coefficient represents the flow of fluid in the wellbore;

[0023] The transient parameters of the wellbore are determined according to the well parameters, oil and gas exploration parameters, the preset skin factor, and the preset wellbore reservoir coefficient; wherein the transient parameters of the wellbore include at least one of the pressure in the wellbore and the exchange rate of the fluid in the wellbore.

[0024] Optionally, the transient parameters of the wellbore are determined according to the well parameters, the oil and gas exploration parameters, the preset skin factor, and the preset wellbore reservoir coefficient, including:

[0025] Obtaining the transient parameters of the wellbore at a preset historical moment as the third historical parameter;

[0026] The transient parameters of the wellbore are determined according to the third historical parameter, the well parameter, the oil and gas exploration parameter, the preset skin factor, and the preset wellbore reservoir coefficient.

[0027] In a second aspect, the present application provides a fracture reservoir numerical simulation device, comprising:

[0028] An acquisition module, used to acquire oil and gas exploration parameters of a preset area; wherein the oil and gas exploration parameters include at least one of a reservoir parameter, a fracture parameter, and a fluid parameter;

[0029] The first determination module is used to determine a transient correction factor according to reservoir parameters and fluid parameters; wherein the transient correction factor represents the transient flow capacity between underground fractures and underground matrix, and the underground matrix represents the underground geological structure;

[0030] The second determination module is used to determine transient parameters according to the transient correction factor and the oil and gas exploration parameters; wherein the transient parameters characterize the properties of the oil and gas reservoirs in the preset area at the current moment, and the transient parameters are used to predict the oil and gas production value.

[0031] According to a third aspect of the present application, an electronic device is provided, including:

[0032] Processor and memory;

[0033] Memory stores computer-executable instructions;

[0034] The processor executes the computer-executable instructions stored in the memory, so that the electronic device executes the method of any one of the first aspects of the invention.

[0035] In a fourth aspect, the present application provides a computer-readable storage medium, in which computer-executable instructions are stored. When the computer-executable instructions are executed by a processor, they are used to implement the invention name method as described in any one of the first aspects.

[0036] The present application provides a method, device, equipment and storage medium for numerical simulation of fractured reservoirs, and obtains oil and gas exploration parameters of a preset area, wherein the oil and gas exploration parameters include at least one of reservoir parameters, fracture parameters and fluid parameters. According to the reservoir parameters and fluid parameters, a transient correction factor is determined, and the transient correction factor characterizes the transient flow capacity between underground fractures and underground matrix, and the underground matrix characterizes the underground geological structure. The strength of the transient flow capacity between underground fractures and underground matrix is ​​characterized by the transient correction factor, so that the numerical simulation is more accurate. According to the transient correction factor and the oil and gas exploration parameters, a transient parameter is determined, and the transient parameter characterizes the properties of the oil and gas reservoir in the preset area at the current moment, and the transient parameter is used to predict the oil and gas production value. By determining the transient correction factor through the reservoir parameters and the fluid parameters, the transient flow characteristics of the fractures and the vicinity of the fractures are taken into account, and the early transient unstable flow can be accurately obtained, so that the fractured reservoir can be simulated more accurately, so that the oil and gas production value can be more accurately predicted. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0038] Figure 1 A schematic diagram of a flow chart of a numerical simulation method for a fractured reservoir provided in an embodiment of the present application;

[0039] Figure 2 A schematic diagram of the transient correction factor provided in an embodiment of the present application changing with time;

[0040] Figure 3 A schematic diagram of another method for numerical simulation of fractured reservoirs provided in an embodiment of the present application;

[0041] Figure 4 The double logarithmic well test curve image of the bottom hole pressure provided in the embodiment of the present application;

[0042] Figure 5 A schematic diagram of the structure of a fracture reservoir numerical simulation device provided in an embodiment of the present application;

[0043] Figure 6 A schematic diagram of the structure of an electronic device provided in an embodiment of the present application.

[0044] The above drawings have shown clear embodiments of the present application, which will be described in more detail later. These drawings and text descriptions are not intended to limit the scope of the present application in any way, but to illustrate the concept of the present application to those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0045] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The implementations described in the following exemplary embodiments do not represent all implementations consistent with the present application. Instead, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0046] First, the terms involved in this application are explained:

[0047] Crack parameters: various indicators and values ​​that describe crack characteristics.

[0048] Fluid parameters: various physical quantities that describe the properties and behavior of fluids.

[0049] Reservoir parameters: important indicators that describe the characteristics of underground reservoirs.

[0050] Fractured reservoirs refer to oil and gas reservoirs with a large number of natural fractures in the reservoir rock. These fractures can significantly affect the permeability and fluid flow characteristics of the reservoir. Fractured reservoirs are of great significance in oil and gas exploration and development because fractures can provide high permeability channels, allowing oil and gas to flow out of the reservoir more easily.

[0051] In the existing numerical simulation methods of oil and gas reservoirs, fractured reservoirs usually refer to fractured oil and gas reservoirs, which refer to oil and gas reservoirs with a large number of natural or artificial fractures. The existence of natural and artificial fractures makes oil and gas reservoirs highly heterogeneous, and the fluid flow shows obvious nonlinearity and complexity. Therefore, although traditional oil and gas reservoir models such as homogeneous models and dual-medium models can describe the seepage behavior of oil and gas reservoirs to a certain extent, their accuracy and applicability are poor when facing complex fracture networks. At present, the commonly used fracture network simulation methods mainly include discrete fracture models and embedded discrete fracture models. The discrete fracture model requires a large number of unstructured grids and local grid encryption measures to achieve sufficient simulation accuracy, with high computational cost and low computational efficiency. The embedded discrete fracture model divides the matrix and fracture grids separately. Based on the steady-state flow assumption, it is difficult to accurately simulate the early transient flow of multiphase fluids around the fractures. There are large errors in simulating the early transient flow of fractured reservoirs and the numerical values ​​of related parameters (i.e., the property characteristics of fractured oil and gas reservoirs).

[0052] The present application provides a method, device, equipment and storage medium for numerical simulation of fractured reservoirs, comprising: obtaining oil and gas exploration parameters of a preset area; wherein the oil and gas exploration parameters include at least one of reservoir parameters, fracture parameters and fluid parameters; determining a transient correction factor according to the reservoir parameters and the fluid parameters; wherein the transient correction factor represents the transient flow capacity between underground fractures and underground matrix, and the underground matrix represents the underground geological structure; the strength of the transient flow capacity between underground fractures and underground matrix is ​​represented by the transient correction factor, so as to make the numerical simulation more accurate; determining a transient parameter according to the transient correction factor and the oil and gas exploration parameters; wherein the transient parameter represents the properties of the oil and gas reservoir in the preset area at the current moment, and the transient parameter is used to predict the oil and gas production value. The transient correction factor is determined by reservoir parameters and fluid parameters, and the transient flow characteristics of fractures and their vicinity are taken into account. The early transient unstable flow can be accurately obtained, making the transient parameters of the fractured reservoir finally simulated more accurate, thereby enabling a more accurate prediction of oil and gas production value. At the same time, the matrix grid of the structured grid is constructed, and the fracture grid is confirmed based on the matrix grid, thereby reducing the computational cost.

[0053] The technical solution of the present application and how the technical solution of the present application solves the above-mentioned technical problems are described in detail below with specific embodiments. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0054] Figure 1 A numerical simulation method for a fractured reservoir is provided in an embodiment of the present application. Figure 1 As shown, a fracture reservoir numerical simulation method of this embodiment includes:

[0055] S101. Obtain oil and gas exploration parameters of a preset area; wherein the oil and gas exploration parameters include at least one of reservoir parameters, fracture parameters, and fluid parameters.

[0056] The preset area may refer to a specific unconventional reservoir, which may be an unconventional reservoir to be mined or an unconventional reservoir under exploitation. Most unconventional reservoirs have natural fractures and are fractured reservoirs. Fractured oil and gas reservoirs refer to oil and gas reservoirs with a large number of natural fractures or artificial fractures. The presence of natural fractures and artificial fractures makes the oil and gas reservoirs highly heterogeneous, and the fluid flow shows obvious nonlinearity and complexity.

[0057] Reservoir parameters may include reservoir size information, matrix permeability, matrix porosity, etc. Fracture parameters may include artificial fracture position coordinates, natural fracture position coordinates, fracture permeability, fracture porosity, etc. Fluid parameters may include fluid viscosity, fluid density, fluid relative permeability, volume coefficient, etc. Fluid parameters include one or more of water phase fluid parameters, oil phase fluid parameters, and gas phase fluid parameters. When the fluid parameters only include one of the water phase fluid parameters, oil phase fluid parameters, and gas phase fluid parameters, it is a numerical simulation method for a single-phase oil and gas reservoir, and the relevant equations in the embodiment of the present application only include the corresponding single-phase fluid parameters. For example: when the fluid parameters only include the oil phase fluid parameters, the oil phase fluid parameters include oil phase fluid viscosity, oil phase fluid density, oil phase relative permeability, oil phase volume coefficient, etc. Then the relevant equations in the embodiment of the present application only include the oil phase fluid parameters. When the fluid parameters include two or more of the water phase fluid parameters, oil phase fluid parameters, and gas phase fluid parameters, it is a numerical simulation method for a multiphase oil and gas reservoir, and the relevant equations in the embodiment of the present application include the corresponding multiphase fluid parameters. For example, when the fluid parameters include water phase fluid parameters and oil phase fluid parameters, the water phase fluid parameters include water phase fluid viscosity, water phase fluid density, water phase relative permeability, water phase volume coefficient, etc., and the oil phase fluid parameters include oil phase fluid viscosity, oil phase fluid density, oil phase relative permeability, oil phase volume coefficient, etc. Then, the relevant equations in the embodiments of the present application include the water phase fluid parameters and the oil phase fluid parameters.

[0058] By setting the fluid parameters of the water phase, the oil phase fluid parameters, and the gas phase fluid parameters, the numerical simulation of single-phase and multi-phase fluid oil and gas reservoirs can be flexibly controlled; while considering the differences in fluid parameters between different fluids, the numerical simulation results can be made more accurate.

[0059] S102, determining a transient correction factor according to reservoir parameters and fluid parameters; wherein the transient correction factor represents the transient flow capacity between underground fractures and underground matrix, and the underground matrix represents the underground geological structure;

[0060] Among them, according to the relevant theories such as seepage mechanics, there is a situation where the matrix has a stronger ability to flow into the fracture, and this ability gradually weakens with the increase of time. In order to accurately simulate the transient flow between the fracture and the matrix, a transient correction factor is introduced. The introduction of the transient correction factor can make it possible to obtain more accurate property characteristics of the oil and gas reservoir when the matrix has a stronger ability to flow into the fracture.

[0061] According to the reservoir parameters and fluid parameters, the transient correction factor is obtained.

[0062] In this embodiment, the fluid parameters include fluid viscosity, volume coefficient, and fluid matrix relative permeability; the reservoir parameters include matrix permeability and matrix porosity; and the transient correction factor is determined according to the reservoir parameters and the fluid parameters, including:

[0063] A transient correction factor is obtained according to fluid viscosity, volume coefficient, matrix permeability, preset matrix grid length, preset compressibility, fluid matrix relative permeability, matrix porosity, and simulation time; wherein the simulation time represents the length of time from the moment when the oil and gas exploration parameters are obtained to the current moment.

[0064] Among them, fluid viscosity, volume coefficient, matrix permeability, preset matrix grid length, preset compressibility, fluid matrix relative permeability, and matrix porosity are all obtained in advance and input into the electronic device. They can be obtained by manual measurement or from existing data. A transient correction parameter formula can be set, and then the fluid viscosity, volume coefficient, matrix permeability, preset matrix grid length, preset compressibility, fluid matrix relative permeability, and matrix porosity are input into the transient correction parameter formula to obtain transient correction parameters. The simulation time is obtained and updated in real time.

[0065] Fluid viscosity is a physical quantity that describes the internal friction resistance of a fluid. Viscosity reflects the ability of a fluid to resist deformation during flow. It includes: aqueous fluid viscosity, oil phase fluid viscosity, and gas phase fluid viscosity.

[0066] Volume coefficient is a physical quantity used to describe the volume change of a substance under different conditions; volume coefficients include: water phase volume coefficient, oil phase volume coefficient, and gas phase volume coefficient.

[0067] Matrix permeability is an important parameter that describes the flow capacity of fluid in porous media (such as rocks, soils or other materials), and reflects the permeability and flow resistance of fluid in porous media.

[0068] Fluid matrix relative permeability refers to the ratio of the magnetization degree of a material in a magnetic field to its magnetization degree in a vacuum. It is a dimensionless physical quantity used to describe the material's ability to respond to a magnetic field. Fluid matrix relative permeability includes: relative permeability of the oil phase, relative permeability of the water phase, and relative permeability of the gas phase.

[0069] The preset compressibility factor is a dimensionless physical quantity used to describe the degree of deviation of the actual gas from the ideal gas behavior. It is of great significance in thermodynamics and fluid mechanics.

[0070] Matrix porosity refers to the ratio of the pore volume of the matrix part to the total volume in porous media such as rock or soil.

[0071] The transient correction factor is calculated by comprehensively considering fluid viscosity, volume coefficient, matrix permeability, preset matrix grid length, preset compressibility, fluid matrix relative permeability, matrix porosity and simulation time. By considering multiple parameters, the transient correction factor can be made more accurate.

[0072] In this embodiment, the method further includes:

[0073] If the simulation time is within the preset time range, a transient correction factor is obtained according to the fluid viscosity, the volume coefficient, the matrix permeability, the preset matrix grid length, the preset compressibility coefficient, the fluid matrix relative permeability, the matrix porosity, and the simulation time;

[0074] If the simulation time is not within the preset time range, the transient correction factor is determined to be a preset value.

[0075] Among them, a time range is set in advance. After the simulation time is obtained, it is determined whether the simulation time is within the preset time range. If so, the transient correction factor can be calculated according to the fluid viscosity, volume coefficient, matrix permeability, preset matrix grid length, preset compression coefficient, fluid matrix relative permeability, matrix porosity, and simulation time; if not, the transient correction factor is determined to be a fixed preset value, for example, the preset value can be 1.

[0076] Figure 2 is a schematic diagram of the transient correction factor changing with time. Figure 2 As shown, the preset time range can be 10 2 The transient correction factor gradually decreases with the increase of time (i.e., dimensionless time) until it reaches the preset value and remains unchanged; according to relevant theories such as seepage mechanics, in the early stage of simulation (i.e., the simulation time is within the preset time range), the ability of the matrix to flow into the crack is stronger, which can be manifested as the conductivity between the matrix and the crack grid (i.e., the transient correction factor) changes with the simulation time; as the simulation time gradually increases, the ability of the matrix to flow into the crack becomes smaller, and the conductivity between the matrix and the crack grid gradually decreases; until the flow between the matrix and the crack is already in a stable state (i.e., the simulation time is not within the preset range), the transient correction factor is 1.

[0077] Transient correction factor T f satisfy:

[0078]

[0079] Among them, T f is the transient correction factor, k m is the matrix permeability, subscript o represents the oil phase; subscript w represents the water phase; subscript g represents the gas phase; μ is the fluid viscosity; B is the volume coefficient; k ro is the relative permeability of the water phase; k rw Relative permeability of oil phase; k rg is the relative permeability of the gas phase; t is the simulation time; a m is half the length of the matrix grid; is the matrix porosity; C t is the comprehensive compression factor.

[0080] Optionally, the fluid parameters of the corresponding phase can be retained according to the fluid parameters of the actual phase, thereby obtaining a transient correction factor, wherein the fluid parameters of the corresponding phase include the volume coefficient of the corresponding phase, the relative permeability of the corresponding phase, and the fluid viscosity of the corresponding phase. For example, if only the fluid parameters of the oil phase are included, then the transient correction factor T f satisfy:

[0081]

[0082] By calculating the transient correction factor using detailed parameters within the preset time range, and using the preset value outside the preset time range, it conforms to the actual situation; at the beginning, the ability of the matrix to flow into the crack is stronger, and as time goes by, this ability gradually weakens until it has almost no effect; by setting the transient correction factor, the transient parameters obtained at the beginning of the numerical simulation can be made more accurate.

[0083] S103, determining transient parameters according to the transient correction factor and the oil and gas exploration parameters; wherein the transient parameters represent the properties of the oil and gas reservoirs in the preset area at the current moment, and the transient parameters are used to predict the oil and gas production value.

[0084] Exemplarily, after the transient correction factor is obtained, the transient parameter can be calculated according to the transient correction factor, as well as oil and gas exploration parameters such as reservoir parameters, fracture parameters, and fluid parameters. The transient parameter can characterize the properties of the oil and gas reservoir in the preset area at the current moment, for example, the fluid exchange rate between the matrix and the fracture of the oil and gas reservoir, the pressure of the matrix, the saturation of the fluid in the matrix, the pressure of the fracture, the saturation of each fluid in the fracture, the pressure of the wellbore, and the fluid exchange rate in the well. Subsequent exploitation can predict the oil and gas production value based on the transient parameters. The calculation formula of the transient parameter can be set in advance, and the transient correction factor and the oil and gas exploration parameter can be substituted into the preset calculation formula to automatically obtain the transient parameter.

[0085] In this embodiment, the transient parameters are determined according to the transient correction factor and the oil and gas exploration parameters, including:

[0086] According to the reservoir parameters and the fracture parameters, the conductivity between the preset matrix grid and the preset fracture grid is obtained; wherein the matrix grid represents the underground matrix structure, the fracture grid represents the distribution of the underground fractures, and the conductivity represents the characteristics of the underground soil;

[0087] According to the conductivity, transient correction factor, and oil and gas exploration parameters, the transient parameters of the matrix grid and the transient parameters of the fracture grid are obtained.

[0088] The reservoir parameters and fracture parameters are substituted into the preset conductivity calculation formula to obtain the conductivity. Then, according to the conductivity, transient correction factor, and oil and gas exploration parameters, the transient parameters and the transient parameters of the fracture grid can be calculated.

[0089] The transient parameters include: transient parameters of matrix grid, transient parameters of fracture grid, and transient parameters of well; the transient parameters of matrix include: saturation of matrix grid at the current moment, pressure of matrix grid at the current moment, and fluid exchange rate between matrix grid and fracture grid; the transient parameters of fluid include: saturation of fluid grid at the current moment, pressure of fluid grid at the current moment, and fluid exchange rate between matrix grid and fracture grid; the transient parameters of well include: pressure of well at the current moment, and fluid exchange rate of well.

[0090] According to the reservoir parameters and fracture parameters, the size of the structured hexahedral grid (cube or cuboid) is determined to generate a matrix grid; according to the fracture parameters, a fracture physical model is constructed; the intersection relationship between the fracture physical model and the matrix grid is obtained; according to the intersection relationship, the fracture grid is obtained. The fracture physical model refers to a model that simulates the length, width, inclination and spatial distribution of the fracture after treating the fracture as a discrete geometric entity.

[0091] After obtaining the fracture grid and matrix grid, if the embedded discrete fracture model is used, the matrix-grid conductivity calculation formula is:

[0092]

[0093] Wherein, the superscript nnc represents non-adjacent connection pairs; T is the conductivity between non-adjacent connection pairs; k f is the fracture permeability, k m is the permeability of the matrix; A f is the contact area; x n is the normal distance to the fracture surface; v is the volume of the matrix grid.

[0094] If the embedded discrete fracture model is used, the matrix-grid conductivity calculation formula is:

[0095]

[0096] Among them, A f⊥ is the area of ​​the crack projected onto the matrix grid surface; is the distance from the center of the projected matrix grid to the center of the crack, k m is the permeability of the projected matrix grid, k f is the fracture permeability; the subscript p represents the parameter under projection.

[0097] The advantages of this setting are: by comprehensively considering reservoir parameters, fracture parameters, conductivity, and transient correction factors, the structure of the underground matrix and fractures and their interactions can be described more accurately; transient parameters can reflect the dynamic changes of the reservoir in different time periods; and by comprehensively considering multiple parameters, the uncertainty of the model can be reduced and the reliability of the simulation results can be improved.

[0098] In this embodiment, the transient parameters of the matrix grid and the transient parameters of the fracture grid are obtained according to the conductivity, the transient correction factor, and the oil and gas exploration parameters, including:

[0099] Obtaining a transient parameter of the matrix grid at a preset historical moment as a first historical parameter; and obtaining a transient parameter of the fracture grid at a preset historical moment as a second historical parameter;

[0100] Obtaining a transient parameter of the matrix grid at the current moment according to the conductivity, the reservoir parameter, the fluid parameter, the transient correction factor, and the first historical parameter; wherein the transient parameter of the matrix grid at the current moment includes at least one of a transient exchange velocity between the matrix grid and the fracture grid, a saturation of the matrix grid, and a pressure of the matrix grid;

[0101] According to the conductivity, the reservoir parameter, the fluid parameter, the fracture parameter, the transient correction factor, and the second historical parameter, a transient parameter of the fracture grid at the current moment is obtained; wherein the transient parameter of the fracture grid at the current moment includes at least one of a fluid exchange rate between the matrix grid and the fracture grid, a saturation of the fracture grid, and a pressure of the fracture grid.

[0102] Among them, the first historical parameter and the second historical parameter are both known parameters, which are parameters obtained at a certain time in the past; the calculation formula for calculating the transient parameters of the matrix grid can be pre-set as the first formula, and the calculation formula for calculating the transient parameters of the fracture grid can be pre-set as the second formula. Substitute the conductivity, reservoir parameters, fluid parameters, transient correction factor, and the first historical parameter into the first formula to automatically obtain the transient parameters of the matrix grid. Substitute the conductivity, reservoir parameters, fluid parameters, fracture parameters, transient correction factor, and the second historical parameter into the second formula to automatically obtain the transient parameters of the fracture grid.

[0103] The preset historical moment can be the previous moment; a time period can also be set, for example, if each time period is one hour, then the preset historical moment is the previous hour; if each time period is one day, then the preset historical moment is the previous day.

[0104] When the first historical parameter is the saturation, pressure, and fluid exchange rate of the matrix grid at the previous moment (n); according to the conductivity, reservoir parameters, fluid parameters, transient correction factor, and the saturation, pressure, and fluid exchange rate of the matrix grid at the previous moment (n), the solution at the next moment is obtained to obtain the saturation, pressure, and flow rate (i.e., fluid exchange rate) of the matrix grid at the current moment (n+1).

[0105] The transient parameters of the matrix grid at the current moment can be obtained as follows:

[0106]

[0107] Wherein, the subscript α represents any one of the oil phase, water phase or gas phase, and one phase corresponds to one equation. If only one of the oil phase, water phase or gas phase is included, then there is only one equation for the corresponding phase; if at least two of the oil phase, water phase or gas phase are included, then there are multiple equations corresponding to all phases, that is, there are as many corresponding equations as there are phases; S is the saturation of the fluid; φ m is the porosity of the matrix; △t is the time difference between the current time step and the previous time step; is the Darcy velocity; V is the grid volume; is the fluid exchange rate between the fracture and the matrix; R is the residual value; ρ is the density of the fluid; q is the fluid exchange velocity.

[0108] When the second historical parameter is the saturation, pressure, and fluid exchange rate of the fracture grid at the previous moment (n); according to the conductivity, reservoir parameters, fluid parameters, fracture parameters, transient correction factor, and the saturation, pressure, and fluid exchange rate of the matrix grid at the previous moment (n), the saturation, pressure, and flow rate between grids (i.e., fluid exchange rate) and other parameters of the fracture grid at the current moment (n+1) are obtained.

[0109] Among them, the transient parameters of the crack grid at the current moment can be obtained as:

[0110]

[0111] Wherein, the subscript α represents any one of the oil phase, water phase or gas phase, and one phase corresponds to one equation. If only one of the oil phase, water phase or gas phase is included, then there is only one equation for the corresponding phase; if at least two of the oil phase, water phase or gas phase are included, then there are multiple equations corresponding to all phases, that is, there are as many corresponding equations as there are phases; S is the saturation of the fluid; φf is the porosity of the fracture; △t is the time difference between the current time step and the previous time step; is the Darcy velocity; V is the grid volume; is the fluid exchange rate between the fracture and the matrix; R is the residual value; ρ is the density of the fluid; q is the fluid exchange velocity.

[0112] This setting can enhance the stability and reliability of the model; by comprehensively considering multiple parameters, it can reduce the uncertainty of the model and improve the reliability of the simulation results; at the same time, the fractures and matrix are gridded and structured grids are used to avoid complex grid division. It has strong applicability and can be applied to a large number of fractures and fracture intersections to support the numerical simulation of complex reservoirs (i.e., discrete reservoirs with multiple fractures).

[0113] In this embodiment, it also includes:

[0114] Acquire well parameters of a preset area, and acquire a preset skin factor and a preset wellbore reservoir coefficient; wherein the well parameters represent the mining information of the wellbore in the preset area, the preset skin factor represents the degree of formation damage in the preset area, and the preset wellbore reservoir coefficient represents the flow of fluid in the wellbore;

[0115] The transient parameters of the wellbore are determined according to the well parameters, oil and gas exploration parameters, the preset skin factor, and the preset wellbore reservoir coefficient; wherein the transient parameters of the wellbore include at least one of the pressure in the wellbore and the exchange rate of the fluid in the wellbore.

[0116] Among them, well parameters, oil and gas exploration parameters, preset skin factors, and preset wellbore reservoir coefficients are acquired in advance, and can be acquired manually or from existing data.

[0117] The preset skin factor represents the degree of formation damage near the well, which is equivalent to adding an additional resistance to the fluid flow; the preset skin factor s usually ranges from -3 to 20, and is generally between 0 and 1; the preset wellbore reservoir coefficient represents that due to the large volume of the wellbore, when the well is just opened, the fluid stored in the wellbore begins to flow first, resulting in a smaller early pressure drop, which represents the early transient flow characteristics of the well; the wellbore reservoir coefficient C usually ranges from 0 to 10 or more, and is generally also between 0 and 1.

[0118] Well parameters include: the proportion of a certain fluid in the well, the daily production of the well (i.e. the fluid exchange rate of the well); when the fluid exchange rate of the well is square meters per day, the fluid exchange rate of the well can be regarded as the daily production of the well.

[0119] The advantages of this setting are: the additional resistance of the matrix in and near the fracture is taken into account through the wellbore reservoir coefficient C and the preset skin factor s; the early transient flow characteristics are accurately simulated, and the early transient flow characteristics under the influence of the wellbore reservoir effect and the additional additional resistance of the matrix in the fracture and near the wellbore are established, which can enhance the stability and reliability of the model; by comprehensively considering multiple parameters, the uncertainty of the model can be reduced and the reliability of well prediction can be improved.

[0120] In this embodiment, the transient parameters of the wellbore are determined according to the well parameters, oil and gas exploration parameters, the preset skin factor, and the preset wellbore reservoir coefficient, including:

[0121] Obtaining the transient parameters of the wellbore at a preset historical moment as the third historical parameter;

[0122] The transient parameters of the wellbore are determined according to the third historical parameter, the well parameter, the oil and gas exploration parameter, the preset skin factor, and the preset wellbore reservoir coefficient.

[0123] Among them, the third historical parameters are all known parameters, which are transient parameters of the well obtained at a certain time in the past; the calculation formula for calculating the transient parameters of the wellbore can be pre-set, which is the third formula. Then, the third historical parameters, well parameters, oil and gas exploration parameters, preset skin factors, and preset wellbore reservoir coefficients are substituted into the third formula to automatically obtain the transient parameters of the wellbore.

[0124] The third historical parameter may be the wellbore pressure at a previous moment, or the fluid exchange rate in the wellbore (ie, the daily production of the well).

[0125] The fluid exchange rate of the wellbore at the current moment satisfies:

[0126]

[0127] Wherein, the subscript α represents any one of the oil phase, water phase or gas phase, and one phase corresponds to one equation. If only one of the oil phase, water phase or gas phase is included, then there is only one equation for the corresponding phase; if at least two of the oil phase, water phase or gas phase are included, then there are multiple equations corresponding to all phases, that is, there are as many corresponding equations as there are phases; w f is the crack opening; k f is the fracture permeability; k rα is the relative permeability of a phase; L is the length of the fracture grid, m; W is the height of the fracture grid, m; r w is the wellbore radius; p e is the pressure of the grid where the well is located; p wfis the bottom hole pressure; the superscript n+1 indicates the n+1 moment; s is the skin factor, which represents the degree of formation damage near the well, which is equivalent to adding an additional resistance to the fluid flow; h is the reservoir thickness; μ is the fluid viscosity; C is the wellbore storage coefficient. Due to the large volume of the wellbore, when the well is just opened, the fluid stored in the wellbore begins to flow first, resulting in a smaller pressure drop in the early stage; Q is the production of the well, in cubic meters per day (i.e. m 3 / day); q is the fluid exchange rate; the unit is cubic meter per day (i.e. m 3 / day); α It is the proportion of a certain phase in the fluid in the well.

[0128] The advantages of this setting are: it can enhance the stability and reliability of the model; by comprehensively considering multiple parameters, it can reduce the uncertainty of the model and improve the reliability of the acquisition of wellbore instantaneous parameters.

[0129] The present application provides a method for numerical simulation of fractured reservoirs. The method characterizes the transient flow capacity between underground fractures and underground matrix through a transient correction factor, so that the transient flow between early fractures and the matrix can be accurately simulated, thereby improving the numerical value of the fractured reservoir value (the numerical value of the fractured reservoir value may refer to the transient parameter) simulation accuracy.

[0130] Figure 3 A schematic diagram of another method for numerical simulation of fractured reservoirs provided in an embodiment of the present application. Figure 3 As shown, the method can be performed by an electronic device or other electronic devices, and this embodiment is not particularly limited here. Figure 3 As shown, the method includes:

[0131] S301, establishing a physical model, wherein the physical model includes: a well physical model, a fracture physical model and a reservoir physical model.

[0132] The model assumes that: the pressure and temperature at each point are the same under initial conditions; the fluid flow follows Darcy's law; the effect of temperature on fluid flow is ignored; the fluid only flows into the wellbore through artificial fractures; and the reservoir boundary is a closed boundary or a constant pressure boundary.

[0133] The method to establish the physical model is:

[0134] Input reservoir parameters and establish a reservoir physical model, wherein the reservoir parameters include: reservoir size information, matrix permeability, and matrix porosity.

[0135] Input fracture parameters and establish a fracture physical model, wherein the fracture parameters include: position coordinates of artificial fractures and natural fractures, fracture permeability, and fracture porosity.

[0136] Input fracture parameters and establish a well physical model, wherein the well parameters include: well coordinates.

[0137] S302, establishing a matrix grid and a fracture grid, and obtaining the conductivity of the matrix-fracture grid.

[0138] The method of establishing the matrix grid and the fracture grid is as follows:

[0139] According to the parameters such as reservoir size and fracture position coordinates, the size of the structured hexahedral grid (cube or cuboid) is determined to generate the matrix grid. Then, the fracture grid is divided according to the intersection relationship between the fracture and the matrix grid.

[0140] After establishing the matrix grid and the fracture grid, select one of the embedded discrete fracture models or the projection-based embedded discrete fracture model to calculate the conductivity information of the grid:

[0141] If an embedded discrete fracture model is used, the conductivity between grids that are adjacent in the numerical model but not adjacent in the computational domain is calculated by constructing non-adjacent connection (NNC) pairs, and the fractures are coupled with the matrix system to simulate the discrete fracture reservoir. The conductivity calculation formula for matrix-fracture non-adjacent connection pairs is:

[0142]

[0143] Wherein, the superscript nnc represents non-adjacent connection pairs; T is the conductivity between non-adjacent connection pairs; k f is the fracture permeability, k m is the permeability of the matrix; A f is the contact area; x n is the normal distance to the fracture surface; v is the volume of the matrix grid.

[0144] If the embedded discrete fracture model for projection is adopted, the matrix and fracture system are coupled. This model improves the embedded discrete fracture model, projects the fracture onto the three faces of the matrix grid on one side of the fracture, and adds a type of non-adjacent connection between the adjacent matrix grid where the projection face is located and the fracture. The conductivity calculation formula of the added additional connection is:

[0145]

[0146] Among them, A f⊥ is the area of ​​the crack projected onto the matrix grid surface; is the distance from the center of the projected matrix grid to the center of the crack, k m is the permeability of the projected matrix grid, k f is the fracture permeability; the subscript p represents the parameter under projection.

[0147] Among them, Af⊥ is the area of ​​the crack projected onto the matrix grid surface; is the distance from the center of the projected matrix grid to the center of the crack, k m is the permeability of the projected matrix grid, k f is the fracture permeability.

[0148] S303, establishing a mathematical model, wherein the mathematical model includes: a matrix flow equation, a fracture flow equation, and a well equation.

[0149] The matrix flow equation is:

[0150]

[0151] Wherein, the subscript α represents any one of the oil phase, water phase or gas phase, and one phase corresponds to one equation. If only one of the oil phase, water phase or gas phase is included, there is only one equation for the corresponding phase; if at least two of the oil phase, water phase or gas phase are included, there are multiple equations corresponding to all phases, that is, there are as many corresponding equations as there are phases; the subscript m represents the matrix; k m is the permeability of the matrix; k rα is the relative permeability of a phase (i.e., any one of the water phase, oil phase, and gas phase); φ m is the porosity of the matrix; ρ is the density of the fluid; S is the saturation of the fluid; is the Darcy velocity; p is the pressure; g is the gravitational acceleration; q is the fluid exchange rate; μ is the fluid viscosity; V is the grid volume; 24 and 86.4 are unit conversion factors, Is a mathematical operation symbol; q αm is the source and sink term of the matrix grid, representing the flow rate of a phase from the matrix grid to other matrix grids or from other matrix grids into the matrix grid; q αm，f is the flow velocity of a phase from the matrix grid to the fracture grid; z is the height coordinate of the center point of the grid, and t is the time.

[0152] The fracture flow equation is:

[0153]

[0154] Wherein, the subscript α represents any one of the oil phase, water phase or gas phase, and one phase corresponds to one equation. If only one of the oil phase, water phase or gas phase is included, there is only one equation for the corresponding phase; if at least two of the oil phase, water phase or gas phase are included, there are multiple equations corresponding to all phases, that is, there are as many corresponding equations as there are phases; the subscript m represents the matrix; k f is the permeability of the fracture; k rα is the relative permeability of a phase (i.e., any one of the water phase, oil phase, and gas phase); φ fis the porosity of the fracture; ρ is the density of the fluid; S is the saturation of the fluid; is the Darcy velocity; p is the pressure; g is the gravitational acceleration; q is the fluid exchange rate; μ is the fluid viscosity; V is the grid volume; 24 and 86.4 are unit conversion factors, Is a mathematical operation symbol; f 1 is the crack grid 1; f 2 is the crack grid 2; q αf，m is the flow rate of a phase from the fracture grid to the matrix grid; is the flow rate of a phase from fracture grid 1 to fracture grid 2.

[0155] The well equation is:

[0156]

[0157] Q=q o +q w +q g ;

[0158]

[0159] Wherein, the subscript α represents any one of the oil phase, water phase or gas phase, and one phase corresponds to one equation. If only one of the oil phase, water phase or gas phase is included, then there is only one equation for the corresponding phase; if at least two of the oil phase, water phase or gas phase are included, then there are multiple equations corresponding to all phases, that is, there are as many corresponding equations as there are phases; w f is the crack opening; k f is the fracture permeability; k rα is the relative permeability of a phase; L is the length of the fracture grid, m; W is the height of the fracture grid, m; r w is the wellbore radius; p e is the pressure of the grid where the well is located; p wf is the bottom hole pressure; the superscript n+1 indicates the n+1 moment; s is the skin factor, which represents the degree of formation damage near the well, which is equivalent to adding an additional resistance to the fluid flow; h is the reservoir thickness; μ is the fluid viscosity; C is the wellbore storage coefficient. Due to the large volume of the wellbore, when the well is just opened, the fluid stored in the wellbore begins to flow first, resulting in a smaller pressure drop in the early stage; Q is the production of the well, in cubic meters per day (i.e. m 3 / day); q is the fluid exchange rate; the unit is cubic meter per day (i.e. m 3 / day); α is the proportion of a certain phase in the fluid in the well, and t is the time.

[0160] S304, respectively solving the matrix flow equation, the fracture flow equation, and the well equation to obtain the instantaneous parameters of the fracture grid at the current moment, the instantaneous parameters of the matrix grid at the current moment, and the instantaneous parameters of the well at the current moment, wherein the instantaneous parameters of the fracture grid include the flow velocity of a certain phase flowing from the fracture to the matrix grid, the saturation of the fracture grid, and the pressure of the fracture grid; the instantaneous parameters of the fracture grid include: the flow velocity of a certain phase flowing from the matrix grid to the fracture grid, the saturation of the matrix grid, and the pressure of the matrix grid; the instantaneous parameters of the well include: the pressure of the well.

[0161] Among them, based on the principle of automatic differentiation, the finite volume method is used to discretely solve the mathematical model. The divergence operator (div) and gradient operator (grad) programs are written in Matlab to simplify the solution process. According to the saturation and pressure of the matrix grid at the previous moment (n), the saturation, pressure, flow rate between grids and other parameters at the current moment (n+1) are solved. Therefore, the solution formula for the matrix flow equation is:

[0162]

[0163] Among them, the subscript α represents any one of the oil phase, water phase or gas phase, and one phase corresponds to one equation. If only one of the oil phase, water phase or gas phase is included, there is only one equation for the corresponding phase. If at least two of the oil phase, water phase or gas phase are included, there are multiple equations corresponding to all phases; that is, there are as many corresponding equations as there are phases; S is the saturation of the fluid; φ m is the porosity of the matrix; △t is the time difference between the current time step and the previous time step; is the Darcy velocity; V is the grid volume; is the fluid exchange rate between the fracture and the matrix; R is the residual value; ρ is the density of the fluid; q is the fluid exchange velocity.

[0164] Among them, the Darcy velocity in the solution formula of the matrix flow equation is obtained The formula is:

[0165]

[0166] Wherein, the subscript α represents any one of the oil phase, water phase or gas phase, and one phase corresponds to one equation. If only one of the oil phase, water phase or gas phase is included, then there is only one equation for the corresponding phase; if at least two of the oil phase, water phase or gas phase are included, then there are multiple equations corresponding to all phases; that is, there are as many corresponding equations as there are phases; is the Darcy velocity; k m is the permeability of the matrix; k rα is the relative permeability of a phase (i.e., any one of the water phase, oil phase, and gas phase); μ is the fluid viscosity; T ijis the conductivity between grid i and grid j; p is the fluid density; p is the pressure; z is the height coordinate of the center point of the grid;

[0167] The solution formula for the fracture flow equation is:

[0168]

[0169] Among them, the subscript α represents any one of the oil phase, water phase or gas phase, and one phase corresponds to one equation. If only one of the oil phase, water phase or gas phase is included, there is only one equation for the corresponding phase. If at least two of the oil phase, water phase or gas phase are included, there are multiple equations corresponding to all phases; that is, there are as many corresponding equations as there are phases; S is the saturation of the fluid; φ f is the porosity of the fracture; △t is the time difference between the current time step and the previous time step; is the Darcy velocity; V is the grid volume; is the fluid exchange rate; R is the residual value; ρ is the density of the fluid; q is the fluid exchange speed.

[0170] Among them, the Darcy velocity in the solution formula of the fracture flow equation is obtained The formula is:

[0171]

[0172] Wherein, the subscript α represents any one of the oil phase, water phase or gas phase, and one phase corresponds to one equation. If only one of the oil phase, water phase or gas phase is included, then there is only one equation for the corresponding phase; if at least two of the oil phase, water phase or gas phase are included, then there are multiple equations corresponding to all phases; that is, there are as many corresponding equations as there are phases; is the Darcy velocity, T ij is the conductivity between grid i and grid j; ρ is the fluid density; p is the pressure; T ij is the conductivity between grid i and grid j; the subscript N represents the number of non-adjacent connections nnc; z is the height coordinate of the center point of the grid.

[0173] Among them, the formula for solving the fracture flow equation and the formula for solving the fracture flow equation are Fluid exchange rates between fractures and matrix in existing computational embedded discrete fracture models and projection-based embedded discrete fracture models for:

[0174]

[0175] This method assumes that the flow between the matrix and the fracture is already in a stable state, so the conductivity T between the matrix and the fracture grid is nncIt does not change with time and is a constant. However, according to relevant theories such as seepage mechanics, in the early stage of simulation, the ability of the matrix to flow into the crack is stronger, and this ability gradually weakens as time goes by. In order to accurately simulate the transient flow between the early cracks and the matrix, the present invention modifies the formula by the correction factor Tf:

[0176]

[0177] Wherein, the subscript α represents any one of the oil phase, water phase or gas phase, and one corresponds to one equation. If only one of the oil phase, water phase or gas phase is included, there is only one equation for the corresponding phase; if at least two of the oil phase, water phase or gas phase are included, there are multiple equations corresponding to all phases; that is, there are as many corresponding equations as there are phases; the subscript N represents the number of non-adjacent connections nnc; T f is the correction factor; T nnc is the conductivity; ρ is the fluid density; p is the pressure; g is the gravitational acceleration; μ is the fluid viscosity; the subscript N represents the number of non-adjacent connections nnc; z is the height coordinate of the center point of the grid.

[0178] In the early stage of the simulation, the ability of the matrix to flow into the cracks is stronger. As time goes by, this ability gradually weakens. Based on the theory of seepage mechanics, the present invention promotes the relationship between the conductivity T and time, that is, the correction factor T f , correction factor T f The acquisition method is:

[0179]

[0180] Among them, T f is the transient correction factor, k m is the matrix permeability, subscript o represents the oil phase; subscript w represents the water phase; subscript g represents the gas phase; μ is the fluid viscosity; B is the volume coefficient; k ro is the relative permeability of the water phase; k rw Relative permeability of oil phase; k rg is the relative permeability of the gas phase; t is the simulation time; a m is half the length of the matrix grid; is the matrix porosity; C t is the comprehensive compression coefficient; the fluid parameters of the corresponding phase can be retained according to the fluid parameters of the actual phase to obtain the transient correction factor, and the fluid parameters include the volume coefficient of the corresponding phase, the relative permeability of the corresponding phase, and the fluid viscosity of the corresponding phase.

[0181] In order to accurately simulate the transient unstable flow of the early wellbore, the present invention establishes a discrete form of the well equation, and obtains the saturation of each phase and the well pressure at the current moment through the discrete form of the well equation, the saturation of each phase and the well pressure at the previous moment:

[0182]

[0183] Wherein, the subscript α represents any one of the oil phase, water phase or gas phase, and one phase corresponds to one equation. If only one of the oil phase, water phase or gas phase is included, then there is only one equation for the corresponding phase; if at least two of the oil phase, water phase or gas phase are included, then there are multiple equations corresponding to all phases; that is, there are as many corresponding equations as there are phases; w f is the crack opening; k f is the fracture permeability; k rα is the relative permeability of a phase; L is the length of the fracture grid; W is the height of the fracture grid; r w is the wellbore radius; p e is the pressure of the grid where the well is located; p wf is the bottom hole pressure; the superscript n+1 indicates the n+1 moment; s is the skin factor; it represents the degree of formation damage near the well, which is equivalent to adding an additional resistance to the fluid flow, a decimal; h is the reservoir thickness; C is the wellbore storage coefficient. Due to the large volume of the wellbore, when the well is just opened, the fluid stored in the wellbore begins to flow first, resulting in a smaller pressure drop in the early stage; the wellbore storage coefficient C, due to the large volume of the wellbore, when the well is just opened, the fluid stored in the wellbore begins to flow first, resulting in a smaller pressure drop in the early stage; Q is the production of the well, in cubic meters per day (i.e. m 3 / day); α is the proportion of a certain phase in the fluid in the well, a decimal; t is time.

[0184] S305, obtaining the time at each moment and the pressure of the well corresponding to each moment, making the time and pressure dimensionless, and drawing a double logarithmic well test curve image of the bottom hole pressure.

[0185] The double logarithmic well test curve of bottom hole pressure is as follows: Figure 4 As shown, the double logarithmic curve can more clearly reflect the transient flow characteristics of the bottom hole, wherein the solid line represents the double logarithmic graph of the bottom hole pressure and time of the present application; by comparing the double logarithmic curve obtained in the present application with the reference solution, the accuracy of the results obtained by numerical simulation using the method of the present application can be verified.

[0186] Among them, time is made causeless:

[0187]

[0188] Where t is the simulation time; t Dis dimensionless time; k m is the permeability of the matrix; is the porosity of the matrix; C t is the comprehensive compression coefficient; X f is the half length of the crack; μ is the fluid viscosity; 3.6 is the unit conversion factor.

[0189] The bottom hole pressure is transformed into:

[0190]

[0191] Where t is the simulation time; p D is dimensionless pressure; k m is the permeability of the matrix; p i is the initial pressure; q is the fluid exchange rate; μ is the fluid viscosity; h is the reservoir thickness; 1.842 is the unit conversion factor.

[0192] Another numerical simulation method for fractured reservoirs provided in the present application utilizes an established discrete fractured reservoir transient numerical simulation method to simulate the effects of multiphase flow and water injection wells, thereby improving the applicability of the model; the simulation has high accuracy and meets the accuracy requirements of numerical simulation of oil and gas reservoirs; a structured grid is used to avoid complex grid division, and the applicability is strong, and the method can be applied to a large number of fractures and situations where fractures intersect; the numerical model requires a small number of grids and has high computational efficiency, which can greatly save computing costs; complex situations such as multiphase flow, natural fractures and faults can be considered, and the method can be applied to unconventional oil and gas reservoirs, thereby improving the accuracy of numerical simulation of fractured reservoirs.

[0193] Figure 5 The schematic diagram of the structure of a fracture reservoir numerical simulation device provided in the embodiment of the present application. The device of this embodiment can be in the form of software and / or hardware. Figure 5 As shown, a fracture reservoir numerical simulation device 50 provided in an embodiment of the present application includes: an acquisition module 501, a first determination module 502, and a second determination module 503:

[0194] The acquisition module 501 is used to acquire oil and gas exploration parameters of a preset area; wherein the oil and gas exploration parameters include at least one of a reservoir parameter, a fracture parameter, and a fluid parameter;

[0195] The first determination module 502 is used to determine a transient correction factor according to reservoir parameters and fluid parameters; wherein the transient correction factor represents the transient flow capacity between underground fractures and underground matrix, and the underground matrix represents the underground geological structure;

[0196] The second determination module 503 is used to determine transient parameters according to the transient correction factor and the oil and gas exploration parameters; wherein the transient parameters represent the properties of the oil and gas reservoirs in the preset area at the current moment, and the transient parameters are used to predict the oil and gas production value.

[0197] In a possible implementation, the first determining module 502 is used to:

[0198] A transient correction factor is obtained according to fluid viscosity, volume coefficient, matrix permeability, preset matrix grid length, preset compressibility, fluid matrix relative permeability, matrix porosity, and simulation time; wherein the simulation time represents the length of time from the moment when the oil and gas exploration parameters are obtained to the current moment.

[0199] In a possible implementation, the first determining module 502 is used to:

[0200] If the simulation time is within the preset time range, a transient correction factor is obtained according to the fluid viscosity, the volume coefficient, the matrix permeability, the preset matrix grid length, the preset compressibility coefficient, the fluid matrix relative permeability, the matrix porosity, and the simulation time;

[0201] If the simulation time is not within the preset time range, the transient correction factor is determined to be a preset value.

[0202] In a possible implementation, the second determining module 503 is used to:

[0203] According to the reservoir parameters and the fracture parameters, the conductivity between the preset matrix grid and the preset fracture grid is obtained; wherein the matrix grid represents the underground matrix structure, the fracture grid represents the distribution of the underground fractures, and the conductivity represents the characteristics of the underground soil;

[0204] According to the conductivity, transient correction factor, and oil and gas exploration parameters, the transient parameters of the matrix grid and the transient parameters of the fracture grid are obtained.

[0205] In a possible implementation, the second determining module 503 is used to:

[0206] Obtaining a transient parameter of the matrix grid at a preset historical moment as a first historical parameter; and obtaining a transient parameter of the fracture grid at a preset historical moment as a second historical parameter;

[0207] Obtaining a transient parameter of the matrix grid at the current moment according to the conductivity, the reservoir parameter, the fluid parameter, the transient correction factor, and the first historical parameter; wherein the transient parameter of the matrix grid at the current moment includes at least one of a transient exchange velocity between the matrix grid and the fracture grid, a saturation of the matrix grid, and a pressure of the matrix grid;

[0208] According to the conductivity, the reservoir parameter, the fluid parameter, the fracture parameter, the transient correction factor, and the second historical parameter, a transient parameter of the fracture grid at the current moment is obtained; wherein the transient parameter of the fracture grid at the current moment includes at least one of a fluid exchange rate between the matrix grid and the fracture grid, a saturation of the fracture grid, and a pressure of the fracture grid.

[0209] In a possible implementation, the second determining module 503 is used to:

[0210] Acquire well parameters of a preset area, and acquire a preset skin factor and a preset wellbore reservoir coefficient; wherein the well parameters represent the mining information of the wellbore in the preset area, the preset skin factor represents the degree of formation damage in the preset area, and the preset wellbore reservoir coefficient represents the flow of fluid in the wellbore;

[0211] The transient parameters of the wellbore are determined according to the well parameters, oil and gas exploration parameters, the preset skin factor, and the preset wellbore reservoir coefficient; wherein the transient parameters of the wellbore include at least one of the pressure in the wellbore and the exchange rate of the fluid in the wellbore.

[0212] In a possible implementation, the second determination module 503 is used to: obtain a transient parameter of the wellbore at a preset historical moment as a third historical parameter;

[0213] The transient parameters of the wellbore are determined according to the third historical parameter, the well parameter, the oil and gas exploration parameter, the preset skin factor, and the preset wellbore reservoir coefficient.

[0214] Figure 6 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present application. Figure 6 As shown, the electronic device 60 includes:

[0215] The electronic device 60 may include a processor 601 with one or more processing cores, a memory 602 with one or more computer-readable storage media, a communication component 603 and other components. The processor 601 , the memory 602 and the communication component 603 are connected via a bus 604 .

[0216] In a specific implementation process, at least one processor 601 executes the computer execution instructions stored in the memory 602, so that at least one processor 601 executes the above-mentioned method for numerical simulation of fractured reservoirs.

[0217] In the above Figure 6In the illustrated embodiment, it should be understood that the processor may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), etc. A general-purpose processor may be a microprocessor or any conventional processor. The steps of the method disclosed in the invention may be directly implemented as being executed by a hardware processor, or may be executed by a combination of hardware and software modules in the processor.

[0218] The memory may include a high-speed memory (Random Access Memory, RAM), and may also include a non-volatile memory (Non-volatile Memory, NVM), such as at least one disk memory.

[0219] The bus may be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, etc. The bus may be divided into an address bus, a data bus, a control bus, etc. For ease of representation, the bus in the drawings of the present application is not limited to only one bus or one type of bus.

[0220] In some embodiments, a computer program product is also proposed, including a computer program or instructions, which implement the steps in any of the above-mentioned fractured reservoir numerical simulation methods when executed by a processor.

[0221] The specific implementation of the above operations can be found in the previous embodiments, which will not be described in detail here.

[0222] A person of ordinary skill in the art will appreciate that all or part of the steps in the various methods of the above embodiments may be completed by instructions, or by controlling related hardware through instructions. The instructions may be stored in a computer-readable storage medium and loaded and executed by a processor.

[0223] To this end, an embodiment of the present application provides a computer-readable storage medium, in which a plurality of instructions are stored. The instructions can be loaded by a processor to execute the steps in any one of the fractured reservoir numerical simulation methods provided in the embodiments of the present application.

[0224] The storage medium may include: a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, etc.

[0225] According to one aspect of the present application, a computer program product or a computer program is provided. The computer program product or the computer program comprises computer instructions stored in a computer-readable storage medium.

[0226] Since the instructions stored in the storage medium can execute the steps in a method for numerical simulation of fractured reservoirs provided in an embodiment of the present application, the beneficial effects that can be achieved by any method for numerical simulation of fractured reservoirs provided in an embodiment of the present application can be achieved. For details, please refer to the previous embodiments and will not be repeated here.

[0227] It should be noted that, for the aforementioned method embodiments, for the sake of simplicity, they are all expressed as a series of action combinations, but those skilled in the art should be aware that the present application is not limited by the described order of actions, because according to the present application, certain steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in the specification are all optional embodiments, and the actions and modules involved are not necessarily required by the present application.

[0228] It should be further noted that, although the various steps in the flowchart are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence in the order indicated by the arrows. Unless there is a clear description in this article, the execution of these steps is not strictly limited in order, and these steps can be executed in other orders. Moreover, at least a portion of the steps in the flowchart may include multiple sub-steps or multiple stages, and these sub-steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these sub-steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a portion of the sub-steps or stages of other steps.

[0229] It should be understood that the above-mentioned device embodiments are only illustrative, and the device of the present application can also be implemented in other ways. For example, the division of units / modules in the above-mentioned embodiments is only a logical function division, and there may be other division methods in actual implementation. For example, multiple units, modules or components can be combined, or can be integrated into another system, or some features can be ignored or not executed.

[0230] In addition, unless otherwise specified, each functional unit / module in each embodiment of the present application may be integrated into one unit / module, each unit / module may exist physically separately, or two or more units / modules may be integrated together. The above-mentioned integrated unit / module may be implemented in the form of hardware or in the form of a software program module.

[0231] If the integrated unit / module is implemented in the form of hardware, the hardware may be a digital circuit, an analog circuit, etc. The physical implementation of the hardware structure includes but is not limited to transistors, memristors, etc. If not specifically stated, the processor may be any appropriate hardware processor, such as a CPU, a GPU, an FPGA, a DSP, an ASIC, etc. If not specifically stated, the storage unit may be any appropriate magnetic storage medium or magneto-optical storage medium, such as a resistive random access memory RRAM (Resistive Random Access Memory), a dynamic random access memory DRAM (Dynamic Random Access Memory), a static random access memory SRAM (Static Random-Access Memory), an enhanced dynamic random access memory EDRAM (Enhanced Dynamic Random Access Memory), a high-bandwidth memory HBM (High-Bandwidth Memory), a hybrid memory cube HMC (Hybrid Memory Cube), etc.

[0232] If the integrated unit / module is implemented in the form of a software program module and sold or used as an independent product, it can be stored in a computer-readable memory. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art or all or part of the technical solution, can be embodied in the form of a software product, which is stored in a memory and includes several instructions for a computer device (which can be a personal computer, a server or a network device, etc.) to perform all or part of the steps of the various embodiments of the present application. The aforementioned memory includes: U disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), mobile hard disk, disk or optical disk and other media that can store program codes.

[0233] In the above embodiments, the description of each embodiment has its own emphasis. For parts not described in detail in a certain embodiment, please refer to the relevant description of other embodiments. The technical features of the above embodiments can be combined arbitrarily. In order to make the description concise, all possible combinations of the technical features in the above embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0234] Those skilled in the art will readily appreciate other embodiments of the present application after considering the specification and practicing the invention disclosed herein. The present application is intended to cover any modification, use or adaptation of the present application, which follows the general principles of the present application and includes common knowledge or customary techniques in the art that are not disclosed in the present application. The specification and examples are intended to be exemplary only, and the true scope and spirit of the present application are indicated by the following claims.

[0235] It should be understood that the present application is not limited to the precise structures that have been described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present application is limited only by the appended claims.

Claims

1. A method for numerical simulation of fractured reservoirs, characterized in that: Used in electronic equipment, including: Acquiring oil and gas exploration parameters of a preset area; wherein the oil and gas exploration parameters include at least one of a reservoir parameter, a fracture parameter, and a fluid parameter; Determine a transient correction factor according to the reservoir parameters and the fluid parameters; wherein the transient correction factor represents the transient flow capacity between the underground fracture and the underground matrix, and the underground matrix represents the underground geological structure; According to the transient correction factor and the oil and gas exploration parameter, a transient parameter is determined; wherein the transient parameter represents the property of the oil and gas reservoir in the preset area at the current moment, and the transient parameter is used to predict the oil and gas production value.

2. The method according to claim 1, characterized in that The fluid parameters include fluid viscosity, volume coefficient, and fluid matrix relative permeability; The reservoir parameters include matrix permeability and matrix porosity; Determining the transient correction factor according to the reservoir parameter and the fluid parameter includes: The transient correction factor is obtained according to the fluid viscosity, the volume coefficient, the matrix permeability, the preset matrix grid length, the preset compressibility coefficient, the fluid matrix relative permeability, the matrix porosity, and the simulation time; wherein the simulation time represents the length of time from the moment when the oil and gas exploration parameters are obtained to the current moment.

3. The method according to claim 2, characterized in that The method further comprises: If the simulation time is within a preset time range, the transient correction factor is obtained according to the fluid viscosity, the volume coefficient, the matrix permeability, a preset matrix grid length, a preset compressibility coefficient, the fluid matrix relative permeability, the matrix porosity, and the simulation time; If the simulation time is not within the preset time range, the transient correction factor is determined to be a preset value.

4. The method according to any one of claims 1 to 3, characterized in that Determining the transient parameter according to the transient correction factor and the oil and gas exploration parameter includes: According to the reservoir parameters and the fracture parameters, the conductivity between the preset matrix grid and the preset fracture grid is obtained; wherein the matrix grid represents the underground matrix structure, the fracture grid represents the distribution of underground fractures, and the conductivity represents the characteristics of underground soil; According to the conductivity, the transient correction factor, and the oil and gas exploration parameter, the transient parameters of the matrix grid and the transient parameters of the fracture grid are obtained.

5. The method according to claim 4, characterized in that The step of obtaining the transient parameters of the matrix grid and the transient parameters of the fracture grid according to the conductivity, the transient correction factor, and the oil and gas exploration parameter comprises: Obtaining a transient parameter of the matrix grid at a preset historical moment as a first historical parameter; and obtaining a transient parameter of the fracture grid at a preset historical moment as a second historical parameter; Obtaining a transient parameter of the matrix grid at the current moment according to the conductivity, the reservoir parameter, the fluid parameter, the transient correction factor, and the first historical parameter; wherein the transient parameter of the matrix grid at the current moment includes at least one of a transient exchange velocity between the matrix grid and the fracture grid, a saturation of the matrix grid, and a pressure of the matrix grid; According to the conductivity, the reservoir parameter, the fluid parameter, the fracture parameter, the transient correction factor, and the second historical parameter, a transient parameter of the fracture grid at the current moment is obtained; wherein the transient parameter of the fracture grid at the current moment includes at least one of a fluid exchange rate between the matrix grid and the fracture grid, a saturation of the fracture grid, and a pressure of the fracture grid.

6. The method according to claim 1, characterized in that Also includes: Acquire well parameters of a preset area, and acquire a preset skin factor and a preset wellbore reservoir coefficient; wherein the well parameters represent the mining information of the wellbore in the preset area, the preset skin factor represents the degree of formation damage in the preset area, and the preset wellbore reservoir coefficient represents the flow of fluid in the wellbore; The transient parameters of the wellbore are determined according to the well parameters, the oil and gas exploration parameters, the preset skin factor, and the preset wellbore reservoir coefficient; wherein the transient parameters of the wellbore include at least one of the pressure in the wellbore and the exchange rate of the fluid in the wellbore.

7. The method according to claim 6, characterized in that Determining the transient parameters of the wellbore according to the well parameters, the oil and gas exploration parameters, the preset skin factor, and the preset wellbore reservoir coefficient includes: Obtaining a transient parameter of the wellbore at a preset historical moment as a third historical parameter; The transient parameters of the wellbore are determined according to the third historical parameter, the well parameter, the oil and gas exploration parameter, the preset skin factor, and the preset wellbore reservoir coefficient.

8. A numerical simulation device for fractured reservoirs, characterized in that: include: An acquisition module, used to acquire oil and gas exploration parameters of a preset area; wherein the oil and gas exploration parameters include at least one of reservoir parameters, fracture parameters, and fluid parameters; A first determination module is used to determine a transient correction factor according to the reservoir parameters and the fluid parameters; wherein the transient correction factor represents the transient flow capacity between the underground fracture and the underground matrix, and the underground matrix represents the underground geological structure; The second determination module is used to determine the transient parameters according to the transient correction factor and the oil and gas exploration parameters; wherein the transient parameters represent the properties of the oil and gas reservoirs in the preset area at the current moment, and the transient parameters are used to predict the oil and gas production value.

9. An electronic device, comprising: Processor and memory; The memory stores computer-executable instructions; The processor executes the computer-executable instructions stored in the memory, so that the electronic device performs the fractured reservoir numerical simulation method according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer-executable instructions, and when the computer-executable instructions are executed by a processor, they are used to implement the method for numerical simulation of fractured reservoirs according to any one of claims 1 to 7.

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