42 results about "Discrete fracture model" patented technology

The invention belongs to the technical field of oil and gas reservoir energy development, and discloses a three-dimensional injection and production well pattern construction method based on a multi-objective algorithm. The problem that the delimited potential area is difficult to effectively use due to the fact that existing potential evaluation is only based on a single index is effectively solved. Comprising the steps that a fault inner core, a fault outer core, a fracture development dense zone and a secondary fracture zone are proposed; carrying out inter-well connectivity analysis on the oil reservoir units by utilizing an oil reservoir engineering method and a numerical simulation streamline method; based on the embedded discrete fracture model, analyzing a remaining oil distribution mode under the control of the nuclear band structure; a multi-parameter comprehensive evaluation system is constructed by combining the remaining oil utilization potential, the displacement power, the flow capacity, the connectivity relation and the reserve abundance; a three-dimensional injection-production well pattern construction technology is formed for an oil reservoir with or without bottom water; based on a multi-objective optimization algorithm, three-dimensional collaborative optimization of the recovery ratio, the well control reserves and the net present value is taken as a core, and a high-efficiency well location deployment technology for different fault zones is constructed.

The invention discloses a complex lithofacies shale oil reservoir multi-scale productivity prediction method and system. The method comprises the following steps: establishing a complex lithofacies shale oil reservoir model with a multi-scale aperture structure; representing the complex lithofacies shale oil reservoir model by adopting a dual-medium model and an embedded discrete fracture model; establishing a complex lithofacies shale oil reservoir seepage model and a numerical solution algorithm considering the starting pressure gradient and the stress sensitive effect, and forming a complex lithofacies shale multi-scale numerical simulation method; the complex lithofacies shale multi-scale numerical simulation method is adopted to carry out complex lithofacies shale oil reservoir seepage numerical simulation, and the shale oil reservoir oil and gas yield is obtained through calculation. According to the method, the seepage simulation and productivity calculation of the complex lithofacies shale oil reservoir can be quickly and accurately realized by establishing the seepage numerical simulation method of the complex lithofacies shale oil reservoir considering the multi-scale aperture characteristics, the starting pressure gradient and the stress sensitive effect.

The invention provides a multiphase multicomponent seepage numerical simulation method based on a discrete fracture model. The method comprises the following steps: step 1, establishing a multi-phase multi-component seepage mathematical model, and solving; step 2, mesh generation of the discrete fracture model; step 3, discretization of a mass conservation equation; step 4, calculating the conductivity between the matrix and the crack; and 5, establishing a nonlinear equation set, and completing solution by adopting an automatic differential technology and a Newton iteration method. According to the method, a complex fracture network is represented through a discrete fracture model, reservoir stress sensitivity and nonlinear seepage characteristics are considered, adsorption and diffusion effects of a surfactant and salt and mechanisms such as capillary pressure, relative permeability curve and osmotic pressure change under the action of the surfactant and the salt are coupled, and a multi-phase multi-component seepage mathematical model is established. According to the method, fracture explicit representation is achieved through a self-adaptive mesh generation method, a finite volume method is adopted for solving, the model is established, and therefore ultra-low permeability-tight oil reservoir development simulation under the influence of a complex fracture network is achieved.

The invention discloses a fractured reservoir acidification method based on a three-dimensional embedded discrete fracture model. The method comprises the following steps: S1, constructing a three-dimensional fractured reservoir physical model containing natural fractures; s2, carrying out structured grid division on the matrix, carrying out unstructured grid division on the crack by utilizing a matrix grid boundary, endowing physical parameters to the physical model, and setting acidification construction time; s3, fluid channeling coefficients between the matrix and the fractures and between the fractures are calculated; s4, based on the characteristics of the three-dimensional embedded discrete fracture model, constructing an acid liquor seepage model and an acid liquor chemical reaction model in the matrix and the fracture, and constructing a pore permeability evolution auxiliary equation of the matrix and the fracture; s5, coupling and solving the model and the equation in the S4; and S6, if the current time step reaches the construction time, obtaining a three-dimensional fractured reservoir acidification numerical simulation result. According to the method, high-precision dynamic coupling simulation of the three-dimensional complex fracture network and the acidification process is realized, and the method has a wide market application prospect.

The invention discloses a fluid-solid coupling reservoir numerical simulation method considering fracture dynamic evolution, and relates to the technical field of complex oil and gas reservoir development, and the method comprises the steps: considering mass conservation and momentum conservation between a fracture and a matrix, and constructing a fractured reservoir model; building a fracture grid based on the embedded discrete fracture model; in each time step, solving a mass conservation equation and a momentum conservation equation, and updating parameters of a seepage field and a stress field; in each time step, judging whether the crack is opened, expanded or closed; the mass and momentum coupling relation between the newly opened fracture grid and the matrix and other fracture grids is constructed, and the mass and momentum coupling relation between the closed fracture grid and the matrix and other fracture grids is disconnected; and performing loop iteration until the simulation is finished. According to the method, the whole process of crack initiation, expansion and closing can be truly represented, the simulation precision is greatly improved, and technical support is provided for fractured reservoir production prediction and development scheme design.

The invention provides a pressure drive fracture network expansion simulation method based on damage mechanics. The method comprises the steps that 1, a reservoir three-dimensional crustal stress field is constructed through a target block geologic model; 2, obtaining a damage-permeability evolution model through rock core physical model experiment data; 3, the damage-permeability evolution model is embedded into a finite element calculation model in a secondary compiling mode, and a damage field of target well fracturing is calculated; 4, comparing the damage field and the microseismic data when the target well is fractured, and iteratively correcting the correlation coefficient in the permeability evolution model; and 5, seepage-deformation-damage coupling finite element calculation is carried out to obtain the fracture network form of pressure flooding water injection. According to the pressure driving fracture network expansion simulation method based on the damage mechanics, a calculation simulation method for fracture network expansion caused by high-pressure water injection is established, pressure driving fracture network expansion simulation calculation which cannot be processed by a conventional discrete fracture model is achieved, better innovativeness and practicability are achieved, and popularization is facilitated.

The invention discloses a fractured medium SDVA self-diverting acid acidification numerical simulation method. The method comprises the following steps: S1, constructing a physical model; s2, dividing a matrix grid and a crack grid on the basis of the physical model, and endowing basic parameters to the grids; s3, constructing a fractured medium SDVA self-diverting acid acidification numerical model; s4, performing coupling iteration to solve the numerical model established in the step S3; s5, judging whether the wormhole of the current time step breaks through or not: if not, continuing numerical simulation of the next time step, updating the viscosity of the self-diverting acid, and repeating the steps S4-S5; and if so, obtaining a numerical simulation result. According to the method, the embedded discrete fracture model can be adopted to solve the problems of distortion of grid division and complex boundary processing during numerical simulation caused by complex fracture grid form or too many fractures during self-diverting acid acidification simulation of the fractured medium, and the self-diverting acid acidification process of the fractured medium SDVA is accurately simulated; and the method has a certain application prospect on the self-diverting acid acidification process of the fractured medium.

The invention relates to the technical field of unconventional oil gas numerical simulation, and provides a deep shale gas multiphase heat-fluid-solid three-field coupling numerical simulation method and system. The method comprises the steps that reservoir parameters, fracture basic parameters and liquid attribute parameters of a target deep shale gas reservoir area are obtained; the reservoir parameters, the fracture basic parameters and the liquid attribute parameters are imported into the trained deep shale gas multiphase heat-fluid-solid three-field coupling numerical simulation model, and target dynamic simulation information is generated, the deep shale gas multiphase heat-fluid-solid three-field coupling numerical simulation model is obtained through coupling solution according to a seepage field equation, a temperature field equation, a stress field equation and a three-pore medium coupling model. The three-pore medium coupling model is obtained by coupling a single-pore medium model, a dual-medium model, a nonlinear unsteady fluid channeling model and an embedded discrete fracture model. According to the method and the device, an efficient and accurate numerical calculation model can be constructed for highly complex heat-fluid-solid information of the shale gas reservoir, and accurate simulation data can be obtained through calculation.

This invention presents a projection embedded discrete fracture model integrating a TPFA and MFD hybrid approach, creating a pEDFM framework for various anisotropic two-phase flow situations. It specifies the distribution of extra pressure freedoms on matrix grids for MFD implementation, maintains f-f connections in TPFA through a standard pEDFM workflow, and introduces a low-conductivity fracture treatment for MFD. It also outlines the derivation of numerical flux calculation formulas for effective m-m and m-f connections. The mixed TPFA-MFD design applies to numerical flux estimation across both K-orthogonal and non-K-orthogonal grids, enhancing computational efficiency and facilitating the spatial discretization of continuity equations for matrix and fracture grids under anisotropic permeability conditions. A global equation system is formulated based on the continuity of effective connections, with time discretization via the implicit backward Euler method and pressure and water saturation distributions determined by a Newton-Raphson based nonlinear solver.

The invention belongs to the technical field of oil-gas exploration and development, and particularly relates to an induced dynamic fracture numerical characterization method based on dynamic embedded discrete fractures. A dynamic embedded discrete fracture-based induced dynamic fracture numerical characterization method is characterized by comprising the following steps: determining an initial position for inducing the growth and extension of a dynamic fracture, and generating a dynamic embedded discrete fracture sheet for describing the growth and extension or closing process of the dynamic fracture at the moment by moment according to a time sequence by taking the initial position as a starting point; space splicing is achieved on the common boundary of the adjacent dynamic embedded discrete fracture pieces, the fracture is kept continuous as a whole, and then a dynamic embedded discrete fracture model covering and inducing the whole life cycle of the dynamic fracture is formed. Effective simulation of the water injection induced dynamic fracture growth extension and closing process in the energy storage and permeability enhancement injection process of the ultra-low permeability reservoir is achieved, and therefore effective technical guidance is provided for implementation of an energy storage and permeability enhancement technology mine field of the ultra-low permeability reservoir.

The present invention discloses a method for rapidly simulating the productivity of unconventional oil and gas reservoirs based on EDFM. Based on the embedded discrete fracture model and combined with the differential method, after dividing each hydraulic fracture into several micro-elements, the number of hydraulic fracture micro-elements in each matrix grid is divided according to the actual matrix grid size, and parameters such as the length of the hydraulic fracture and the average orthogonal distance in the grid are further calculated, so as to calculate the volume coefficient when crossflow occurs between the hydraulic fracture grid and the matrix grid. By coupling the continuous medium model, the deficiencies of the traditional embedded discrete fracture model are overcome. The embedded discrete fracture model is used to characterize hydraulic fractures, and the continuous medium model is used to characterize natural micro-fractures. The obtained model can accurately characterize various types of fractures in the reservoir, and the calculation results of the numerical model obtained in this way are more reasonable and reliable. The method of the present invention helps to study the seepage law in the formation of complex hydraulic fracture networks.

The invention discloses a sea-land transition phase shale gas productivity evaluation method based on p-EDFM, and the method comprises the steps: carrying out the layering processing of a matrix grid according to the longitudinal heterogeneity of sea-land transition phase shale, and introducing physical property parameters and corresponding apparent permeability models for different rocks. Dimension reduction processing is carried out on a fracture surface according to parameters of an artificial fracture, pressure exchange between grids is represented by utilizing a fluid channeling coefficient, flow exchange between different grids is further calculated, and then output of each lithology can be obtained through a horizon tracking mode. The combination of the multi-continuous medium model and the embedded discrete fracture model respectively overcomes the defects of the self model, and can better reflect the heterogeneous formation characteristics of microfractures widely distributed in the shale gas reservoir, large-scale artificial fractures and transition-phase shale gas reservoirs. The method provided by the invention not only can be used for evaluating the productivity of the sea-land transition phase shale gas, but also can be popularized and used for calculating the productivity of unconventional oil and gas reservoirs, and has a relatively high application value.

The invention relates to a buried hill gas storage effective gas storage space evaluation method, and belongs to the technical field of oil-gas exploration. The method comprises the following specific steps: acquiring fracture development parameters; determining the type of a storage space; reservoir logging response characteristics are determined; extracting buried hill cracks; establishing a bedrock geologic model and a bedrock buried hill discrete fracture model of the target area; and importing the results into a gas storage simulation model in the form of data flow, extracting effective gas storage spaces of a substrate and a crack of the buried hill gas storage, and determining a final buried hill building effective gas storage space. Through research on the method for calculating the reservoir space of the buried hill oil and gas reservoir rebuilt gas storage, the problem of invalid reservoir space calculation is deducted, the calculation accuracy is improved, and theoretical support is provided for calculation of the buried hill reservoir building capacity and later injection and production well position deployment.

The present application provides a shale gas complex fracture network characteristic parameter intelligent inversion method and system, the method adopts embedded discrete fracture model to establish the complex fracture network shale gas fracturing productivity model of shale reservoir; after determining the parameter value space to be inverted, the basic calculation examples are obtained based on random sampling, and parameter sensitivity analysis is carried out; the intelligent agent model is used to train the machine learning model with the basic calculation examples as the training samples, and the fracturing productivity prediction model is formed; the target example parameters meeting the error condition are optimized by using the set objective function based on the calculation results of the fracturing productivity prediction model; and then the target example parameters are brought into the complex fracture network shale gas fracturing productivity model to invert the target fracture network characteristic parameter results. The scheme can overcome the problems of time and cost consumption and limited applicability of the prior art, and can realize fast and reliable fitting by combining reservoir numerical simulation, intelligent machine learning model and optimization algorithm, and improve the shale gas complex fracture network characteristic parameter inversion efficiency.

The invention provides a shale oil multi-well crosstalk diagnosis and optimization method based on EDFM and oil-water two-phase coupling, and belongs to the technical field of unconventional oil and gas development. According to the method, an embedded discrete fracture model (EDFM) is utilized to construct a multi-well platform physical model comprising a horizontal shaft, discrete hydraulic fracture networks and a shale matrix, the model is coupled with an oil-water two-phase flow conservation equation, fluid compressibility and fracture pressure sensitivity, and a non-adjacent connection conductivity operator between adjacent well fracture networks is innovatively introduced; the characterization module is used for characterizing a fracturing crosstalk path; and by simulating a double logarithmic pressure drop derivative curve in a multi-well soaking period, identifying pressure balance abnormity caused by adjacent well crosstalk. The defect that a traditional grid encryption technology is large in calculation amount and cannot process complex intersecting cracks is overcome, the position and the flow conductivity of the crosstalk cracks can be accurately recognized, and a scientific basis is provided for evaluating the platform well scale, optimizing the well spacing and the channeling prevention technology.

This invention discloses a method for determining the gas well penetration rate and pressure drop plot through proppant volume conservation numerical simulation, comprising: establishing a gas well numerical model of structural layers and dividing the development sub-layers; acquiring gas saturation and average adsorbed gas content data for each development sub-layer, and establishing three-dimensional models of free gas saturation and adsorbed gas saturation respectively; performing inversion to obtain artificial fracturing parameters; establishing an embedded discrete fracture model; dividing the embedded discrete fracture model into zones; acquiring stress-sensitive data and relative permeability data, and establishing stress-sensitive and relative permeability models; acquiring diffusion coefficient, reservoir temperature and pressure basic parameters, establishing embedded discrete fracture numerical models of fractures at different heights, and using the embedded discrete fracture numerical models to determine the fracture height range; establishing embedded discrete fracture numerical models under different penetration rate conditions, and generating a plot of the relationship between gas well penetration rate and pressure drop through numerical simulation calculation.

The present invention discloses a method for calculating the production of coalbed methane fracturing wells based on embedded flow exchange, belonging to the technical field of geological resource exploration and development, and comprising the following steps: establishing a coalbed methane seepage control equation, using an embedded discrete fracture model to characterize a multi-scale fracture system, and solving the pressure distribution based on the finite volume method; establishing a heterogeneous distribution of coalbed permeability based on the Gaussian distribution, and introducing a multiple seepage mechanism function to characterize the evolution law of coalbed permeability; establishing a coalbed cleat / fracture system based on the Fisher distribution function, considering the evolution of the dynamic fracture width, and combining with the cubic law to establish a self-supporting fracture permeability evolution model; after completing the multi-scale seepage solution of the coalbed methane fracturing well, establishing a basic productivity equation for the coalbed methane fracturing well, discretizing and summing the equation on an orthogonal grid, and substituting the global pressure solution into the productivity equation to obtain the productivity of the coalbed methane fracturing well. The present invention improves the calculation efficiency and accuracy of the productivity of coalbed methane fracturing wells.

The invention relates to a self-adaptive local mesh encryption method based on embedded discrete fractures, which comprises the following steps: aiming at a complex fracture system formed by horizontal well fracturing, establishing a two-dimensional tight reservoir physical model, carrying out initial mesh division, and adopting an EDFM method, two sets of independent mesh systems are adopted for the fractures and a matrix; determining a self-adaptive local grid encryption area; the method comprises the following steps: establishing a self-adaptive local grid encryption criterion based on crack distribution characteristics and physical flow rules, and automatically identifying a key region needing grid encryption: realizing a multi-stage grid encryption strategy, and establishing a tree-shaped hierarchical structure to manage a multi-stage encryption grid system; calculating a connectivity index CI after grid encryption; calculating conductivity, and constructing a conductivity matrix; and solving the pressure and the yield to realize fixed-production pressure solving and fixed-pressure production solving. According to the method, the depiction capability of the embedded discrete fracture model on the flow characteristics near the fracture is improved, and the yield change condition of the fractured reservoir is accurately predicted.

This invention discloses a p-EDFM-based method for evaluating the productivity of marine-continental transitional shale gas. Addressing the vertical heterogeneity of marine-continental transitional shale, the matrix grid is layered, and physical property parameters and corresponding apparent permeability models for different rocks are introduced. The fracture surface is dimensionality-reduced based on artificial fracture parameters, and the crossflow coefficient is used to characterize the pressure exchange between grids. Further calculations of flow exchange between different grids are performed, and the productivity of each lithology can be obtained through stratigraphic tracing. The combination of a multiple continuous medium model and an embedded discrete fracture model overcomes the shortcomings of their respective models, better reflecting the widely distributed microfractures, large-scale artificial fractures, and heterogeneous stratigraphic characteristics of transitional shale gas reservoirs. In addition to evaluating the productivity of marine-continental transitional shale gas, the method proposed in this invention can also be extended to the productivity calculation of unconventional oil and gas reservoirs, demonstrating significant application value.

The stratum heat insulation barrier simulation method based on the projection type embedded discrete fracture model comprises the steps that a physical model of a well drilling area is constructed, the physical model is divided into a matrix grid and a barrier grid according to preset grid parameters, and the barrier grid is arranged in the matrix grid in an embedded mode; determining projection information of the barrier grid in the matrix grid according to different grid connection relations between the barrier grid and the matrix grid; determining geometric factors and geometric heat conductivity coefficients of the barrier grids according to the projection information; and inputting the geometric factor and the geometric heat conductivity coefficient into a preset model to obtain a heat transfer simulation result of the barrier grid. According to the scheme provided by the invention, mass transfer or heat transfer of the matrix grid and the barrier grid is accurately captured according to the geometric position and shape, so that a more accurate simulation result is provided, meanwhile, division of an unstructured grid is avoided, the complexity of equation discretization is reduced, and the calculation efficiency is greatly enhanced.

Reservoir simulation is performed by constructing an embedded discrete fracture model (EDFM) having matrix grid cells (180a) and extra continuum grid cells in the simulation grid. The EDFM is integrated into a multi-porosity-multi-permeability (MPMP) framework of a parallel reservoir simulator. Each fracture polygon of the fractures (181c) in the reservoir is divided into a set of fracture cells for calculating matrix-fracture connections (183b) and fracture-fracture connections (183b), which are all neighbor connections between grid cells that are face or edge neighbors. These neighbor connections may be intra-continuum connections or inter-continua connections that are stored in the matrix grid cells (180a) and / or fracture grid cells in the integrated EDFM / MPMP framework. The reservoir simulation is performed by the parallel reservoir simulator based on the cell connectivity data in the integrated EDFM / MPMP framework to facilitate well production of the reservoir.

The invention relates to a method and a device for calculating a mass exchange coefficient between bedrock and a fracture in an underground reservoir, and belongs to the technical field of seepage simulation of fracture type underground reservoirs. The method for calculating the mass exchange coefficient between the bedrock and the fracture in the underground reservoir comprises the following steps: performing embedded grid division on a bedrock region and a fracture region in the underground reservoir, and determining a connection pair between a fracture grid and a bedrock grid; based on the permeability of the bedrock grid corresponding to the connection pair, determining a Green element function under a bedrock grid permeability main axis coordinate system; source item coordinates in the Green element function are used as variables, integration is conducted on the Green element function along the fracture grids belonging to the same connection pair, and a pressure response function is determined; and based on the pressure response function, determining the conductivity between the bedrock grid and the fracture grid corresponding to the connection pair. According to the method, the calculation precision of mass exchange between the bedrock and the fracture in seepage simulation of the embedded discrete fracture model can be remarkably improved.

The application discloses a kind of deep fracture reservoir thermal flow coupling numerical simulation method and system based on mixed fracture model, and relates to fractured reservoir numerical simulation technical field.The method constructs three types of grid systems of large-scale fracture, natural fracture and matrix in the same calculation domain, respectively using embedded discrete fracture model and double-pore double-permeability model to be coupled representation.Through establishing four types of grid connection relationship, flow and thermal conductivity are calculated differentially, especially introducing improved Vermeulen function to carry out non-steady-state dynamic correction to the exchange between natural fracture and matrix.Based on finite volume method, fully implicit residual equation set is established and solved, and multi-field simulation results are output.The application considers the representation accuracy and calculation efficiency of multi-scale medium under the premise of not multi-level profiling of matrix, and can provide technical support for deep oil and gas reservoir injection-production development and geothermal field efficient exploitation.

The invention provides a method and a system for evaluating a single-section well test based on a discrete fracture network technology. The method comprises the following steps: classifying fractures according to morphological characteristics of a fracture network; constructing a corresponding single-section well test interpretation model and a single-section well test mathematical model based on crack classification by using a discrete crack network technology; respectively inputting the well testing key parameters of each crack classification into a single-section well testing mathematical model, and drawing a single-section double logarithmic well testing curve of each crack classification based on a solving result; and analyzing the single-section double logarithmic well testing curve to obtain an evaluation conclusion of single-section well testing. According to the method, a discrete fracture model (DFN) is adopted for coupling matrix-fracture seepage, and the actual fracturing effect of the deep shale gas well and the complex degree of the fracture network are considered, so that the seepage characteristics of the complex fracture network are accurately represented; the influence of key parameters such as reservoirs and cracks on well test interpretation results is determined by establishing a single-section well test mathematical model, and the accuracy and reliability of well test fracturing effect evaluation under different crack classifications are improved.

Reservoir simulation is performed by constructing an embedded discrete fracture model (EDFM) having matrix grid cells and extra continuum grid cells in the simulation grid. The EDFM is integrated into a multi-porosity-multi-permeability (MPMP) framework of a parallel reservoir simulator. Each fracture polygon of the fractures in the reservoir is divided into a set of fracture cells for calculating matrix-fracture connections and fracture-fracture connections, which are all neighbor connections between grid cells that are face or edge neighbors. These neighbor connections may be intra-continuum connections or inter-continua connections that are stored in the matrix grid cells and / or fracture grid cells in the integrated EDFM / MPMP framework. The reservoir simulation is performed by the parallel reservoir simulator based on the cell connectivity data in the integrated EDFM / MPMP framework to facilitate well production of the reservoir.

Methods and systems for determining pore-volume of a fracture in a core plug. The method includes developing a grid block model constrained by fracture porosity estimated from a mechanical laboratory test, aperture calculation, and discrete fracture model validation. The method further includes determining the natural fracture porosity and pore volume from the equivalent medium for natural fractures, determining oil or gas reserves by calculating the fracture pore volume, and determining fracture porosity measurement from a test to calibrate 3D fracture models. The method also includes determining fracture porosity from a mechanical test, analyzing borehole image logs, developing a geomechanical model and fracture drivers, performing fracture model predictions, validating and calibrating the model, and determining fracture pore-volume of the core plug.

The present invention relates to a method for simulating the flow of CO2 flooding in a fractured reservoir, and particularly to a method for simulating the flow of CO2 flooding in a fractured reservoir using neural network technology. The method comprises the following steps: conducting a survey on the target reservoir, collecting reservoir geological parameters and fracture geometric parameters, and establishing a geometric model of the fractured reservoir; establishing a flash calculation model based on a neural network; establishing an embedded discrete fracture model to describe fractures; establishing a component model to describe the process of CO2 flooding; combining the flash calculation model based on the neural network model with the component model, and considering the embedded discrete fracture model, establishing a flow model for CO2 flooding in the fractured reservoir and performing numerical solution. The method of the present invention can utilize the advantages of the neural network to perform flash calculation quickly and stably, improve the convergence speed of the calculation, and accurately describe the influence of fractures on CO2 flooding.

The present application discloses a fluid-solid coupling numerical simulation method and device based on an embedded discrete fracture model. The reservoir matrix is ​​divided by structured grids, and a discrete fracture model is embedded to construct a geological grid for oil and gas reservoirs. A transfer function is established, and the porous media fluid seepage control equation is formulated accordingly. The equation is solved at each time node to obtain the pore pressure field, and the equivalent pore pressure field is obtained by weighted average as the boundary condition of the solid mechanics control equation. The geological grid model of the oil and gas reservoir is expanded, and the solid mechanics control equation is constructed by combining the fracture-rock constitutive model, the effective stress principle and the stress equilibrium equation. The finite element method and the Newton-Raphson method are used to solve and simulate rock deformation. Based on the constitutive relationship of the composite material, the matrix and fracture seepage properties are updated, and the interaction between the seepage field and the stress field is considered through iterative coupling to achieve multi-field coupling simulation. The problem that the existing methods cannot be applied to real oil and gas reservoirs is solved.

The embodiment of the invention provides a fracture model building method and system based on multi-stage crustal stress parameters, and belongs to the technical field of oil and gas exploration and development. The method comprises the following steps: executing target stratum structure recovery simulation based on geological detection data, and constructing an initial oil and gas reservoir framework body geological model; performing iterative simulation of the discrete fracture model of each stage to obtain a multi-stage discrete fracture initial model; constructing a target function between the multi-stage discrete crack initial model and the crack distribution data of the current target layer; calling a multi-objective function optimizer to execute objective function optimization, and obtaining a final multi-stage discrete fracture model based on an optimization result; and crack attribute parameter models are generated by stages based on the simulation result and the final multi-stage discrete crack model, fusion calculation of the crack attribute parameter models generated by the stages is executed, and a multi-stage stress superposition crack model is obtained. According to the scheme, the spatial distribution states of the cracks in different geological periods can be accurately represented, and a more accurate geological model is constructed.

The invention discloses a fractured reservoir SDVA self-diverting acid two-phase acidification numerical simulation method. The method comprises the following steps: S1, constructing a fractured reservoir SDVA self-diverting acid two-phase acidification numerical simulation physical model; s2, performing matrix grid and fracture grid division on the physical model, and endowing the model with physical parameters; s3, constructing a fractured reservoir SDVA self-diverting acid two-phase acidification numerical simulation model based on the embedded discrete fracture model; s4, the fractured reservoir SDVA self-diverting acid two-phase acidification numerical simulation model of the current time step is solved through coupling iteration, and physical property parameters are updated; s5, judging whether the wormhole of the current time step breaks through or not: if not, continuing numerical simulation of the next time step, updating the model parameters, and repeating the steps S4-S5; and if so, obtaining a fractured reservoir SDVA self-diverting acid two-phase acidification numerical simulation result. According to the method, the two-phase acidification process of the SDVA self-diverting acid of the fractured reservoir can be accurately simulated, and the method has important theoretical and practical significance on acidification development of the fractured reservoir.