31 results about "Discrete fracture model" patented technology

The invention discloses a shale gas reservoir fluid-solid coupling multi-scale numerical simulation method. The method comprises the following steps: obtaining spatial distribution and physical property parameters of organic matters and inorganic matters, constructing a physical model of a micro-scale shale matrix, solving a micro-scale seepage auxiliary equation and a mechanical auxiliary equation, and calculating equivalent seepage and mechanical parameters of the shale matrix core scale; acquiring a natural fracture distribution situation, constructing a rock core scale physical model containing a shale matrix and natural fractures, solving a seepage auxiliary equation and a mechanical auxiliary equation of the rock core scale, and calculating equivalent seepage and mechanical parameters of a shale gas reservoir macro-scale; on the basis, simulating a hydraulic fracture by adopting an embedded discrete fracture model, and establishing a shale gas reservoir macroscopic fluid-solid coupling model; and finally, based on the structured grid, solving the shale gas reservoir fluid-solid coupling model by adopting a mixed numerical discretization method combining simulated finite difference and extended finite elements so as to realize shale gas reservoir fluid-solid coupling numerical simulation with high simulation precision and small calculated amount.

The invention provides an embedded discrete fracture model-based fractured well modeling and simulation method. The method includes: dividing a bed rock system orthogonal coarse meshes, and extracting coarse mesh nodes and fracture information; dividing the system into a bed rock system and a fracture system, and establishing a flow mathematical model for the bed rock system and the fracture system each; establishing a corresponding embedded discrete fracture net model; establishing a bed rock system numerical calculation format based on a simulation finite difference method; analyzing the numerical calculation format of fractures in bed rocks in three different embedded manners; establishing a numerical calculation format of an embedded discrete fracture net system based on a control volume finite difference method; and serving the fracture system as a source term of the bed rock system, and establishing an embedded discrete fracture flow mathematical model by coupling the fracture system and the bed rock system. The embedded discrete fracture model-based fractured well modeling and simulation method can avoid a complicated unstructured mesh generation process, and improve the accuracy and the high efficiency of a fractured well fracture description and simulation method.

The invention discloses an oil-water two-phase non-Darcy seepage numerical simulation method based on a discrete fracture model, and the method comprises the steps: determining an oil-water two-phaseseepage mode, and selecting a low-speed non-Darcy seepage model in a fracture system; selecting a low-speed nonlinear seepage model in the matrix for characterization; establishing continuity equations of an oil phase and a water phase respectively according to the law of conservation of mass; discretizing the continuity equation, and establishing a numerical simulation model; correcting the numerical simulation model by using an embedded discrete fracture model, adding a variety of non-adjacent link information, and establishing a nonlinear equation system; solving the nonlinear equation system to obtain oil-water two-phase pressure and saturation parameters; establishing a water-oil displacement model under a complex fracture condition, performing numerical simulation, and analyzing output characteristics of an injection well and an oil production well. The problem that an existing commercial numerical simulation method cannot simulate two-phase low-speed non-darcy flow in a matrix is solved, and the method has obvious advantages in the aspects of calculation precision and calculation efficiency.

The invention discloses an integrated simulation method coupling the hydraulic fracturing, flowback and production processes of a shale gas reservoir. The method comprises the steps of first, settinga fracture potential expanding path on the basis of stratum natural fracture distribution, and the magnitude and the direction of ground stress; second, dividing a space into unstructured grids by adopting triangular units with all the potential fractures as the grid boundaries; third, using a gas-water two-phase discrete fracture model based on the unstructured grids to calculate the pressure onand the saturation of fractures and substrate grids in the fracturing, flowback and production processes; fourth, simulating the fracture expanding process; fifth, judging the intersection action of the fractures when one fracturing fracture expands forwards and meets one natural fracture; and sixth, simulating the flowback and production processes after the fracturing expanding process simulationis finished. According to the integrated simulation method coupling the hydraulic fracturing, flowback and production processes of the shale gas reservoir, the discrete fracture model and dynamic fractures are used in combination, flow of two phases including fracturing fluid and shale gas in the stratum is taken into consideration, and it is implemented that the shale gas reservoir hydraulic fracturing flowback production process is integrally simulated.

The invention discloses a numerical simulation method suitable for valley width deformation of a high arch dam. The method comprises the following steps of firstly, the stratum information of a dam area is acquired, the landform and rock stratum distribution information is determined, and a geometric model of the dam area is established; secondly, an embedded discrete fracture model is establishedfor a discontinuous structural surface, and mesh generation is conducted on the geometric model by adopting orthogonal meshes; then piecewise linear fitting is conducted on the water storage processline, and the dynamic application process of the water load is determined; correcting the physical and mechanical parameters of the weak structural surface on the basis of considering the degradationeffect of water on the rock mass material; and finally, joint solution of embedded discrete cracks and an extended finite element model is carried out on the water storage process, and simulation of valley width deformation of the high arch dam in the water storage period is achieved. The method is advantaged in that the forms of the fault and the dislocation zone do not need to be considered during mesh generation, so complexity during mesh generation is greatly reduced; and secondly, generation of valley deformation of the high arch dam in the water storage period can be effectively simulated from the perspective of structural surface deformation.

The invention belongs to the field of petroleum engineering, and particularly relates to a fracturing fracture parameter inversion method based on production dynamic automatic history fitting. The method includes the steps that step one, an embedded discrete fracture model is applied to the subdivision of a reservoir, and flow between a transmissibility coupling fracture and a matrix is calculated; step two, a three-dimensional earthquake monitoring model is established, and reservoir changes are simulated; step three, a complex fracture network generation method is established according to afracture form and a discrete fracture inversion algorithm; and step four, a discrete network deterministic inversion algorithm is constructed. According to the fracturing fracture parameter inversionmethod based on the production dynamic automatic history fitting, compared with the prior art, a complex fracturing fracture network is regarded as a discrete fracture network composed of a pluralityof small fracture sections, a three-dimensional monitoring technology is utilized, the discrete network deterministic inversion algorithm is combined for inverting a fracture network form, and the fine fracturing fracture form is described, so that the fracturing effect is evaluated more accurately, and a reference is provided for subsequent development of an oil field.

The invention relates to a flow simulation method suitable for shale gas reservoir thermal exploitation, which comprises the following steps: establishing a gas reservoir geometric model according to the development scale of a shale gas reservoir mine field, the fracture distribution condition after hydraulic fracturing, the size of a reservoir transformation area obtained through microseism and the microfracture distribution; describing an artificial fracture through a discrete fracture model; establishing a shale gas reservoir dual-medium fractured horizontal well seepage field model based on the reservoir transformation area and the reservoir non-transformation area; taking the artificial fracture as a constant-temperature heat source, and establishing a shale gas reservoir thermal field model; and coupling the seepage field model and the thermal field model, subdividing the geometric model based on a Delaunay triangular mesh, and further solving the geometric model to realize numerical simulation of thermal development of the complex fractured shale gas reservoir. According to the invention, the segmented pressure horizontal well thermal development model of the composite gas reservoir of the shale gas reservoir is established, and guidance is provided for shale gas reservoir thermal exploitation potential evaluation and future mine field development.

The invention discloses an unconventional oil and gas reservoir horizontal well fracturing fracture net expansion and production dynamic coupling method, and belongs to the technical field of oil and gas reservoir development. The method comprises the following steps: establishing an unconventional oil and gas reservoir fractured horizontal well complex fracture network model based on a fractured fracture propagation theory; constructing a three-dimensional and three-phase seepage mathematical model of the fractured horizontal well in combination with the embedded discrete fracture model; and establishing a fully implicit numerical calculation model by using a finite difference method and a three-dimensional orthogonal cubic grid, performing iterative solution, and accurately predicting the production dynamic characteristics of the unconventional oil and gas reservoir fractured horizontal well . According to the method, the defect that a traditional fracture network expansion model and a production dynamic prediction model are mutually independent is overcome, and unconventional oil and gas reservoir horizontal well fracture network expansion and production dynamic integrated simulation prediction is achieved by combining the fracture expansion model and the production dynamic prediction model.

The invention relates to an oil reservoir flow full-coupling pressure and production integrated numerical simulation method. The method sequentially comprises the following steps: (1) building a structured reservoir grid and a crack initial unit; (2) calculating the half length of the artificial fracture, the width distribution of the artificial fracture, the pressure distribution of fluid in the artificial fracture, the pressure distribution of a matrix oil phase and the saturation distribution of a matrix liquid phase in the fracturing process; (3) calculating reservoir pressure distribution and reservoir water saturation distribution in the oil well flowback-production process; and (4) calculating the productivity of the oil well. According to the invention, the structured grid and the embedded discrete fracture model are adopted, the structured grid can be beneficial to processing of the oil reservoir boundary problem, and the embedded discrete fracture model has the advantages of being simple in grid division, rapid in calculation, easy to process complex fractures and the like. The invention is used for simulating fracturing, flowback and production processes of oil reservoir development, and oil well production dynamics closer to actual conditions are obtained through integrated combination, so that fracturing construction and production system design are guided.

The invention provides an inclined fracture mesh generation method based on an embedded discrete fracture model, which belongs to the technical field of oil reservoir simulation and comprises the following steps of: establishing a matrix mesh system, acquiring a fracture surface boundary and a projection surface of the matrix mesh system on each coordinate axis plane, inverting the projection of the matrix mesh penetrated by the fracture surface on each projection surface to obtain a matrix mesh penetrated by the fracture surface, dividing a fracture surface by using the boundary of the matrixmesh to obtain a preliminary fracture mesh, and taking the fracture surface boundary as a constraint condition, initially retaining the part of the initial fracture mesh within the fracture boundaryand obtaining the final fracture mesh. According to the method, the embedded discrete fracture model is used for generating any polygonal fracture surface in the stratum, particularly, the inclined fracture meshes can be generated, and the seepage law in the stratum with complex fracture distribution can be studied.

The invention provides an in-crack temporary plugging diversion fracturing simulation method and equipment. The method comprises the following steps: constructing a discrete fracture model based on a discrete element method; combining the fluid flow equation and the rock mass deformation equation based on a weak coupling method, performing discrete and iterative processing on the fluid flow equation to obtain in-crack fluid pressure, and inputting the in-crack fluid pressure into the rock mass deformation equation to obtain crack width; acquiring stress borne by the virtual spring based on the crack width, judging whether the virtual spring is fractured or not according to the stress borne by the virtual spring and the maximum stress of the virtual spring, and if yes, expanding the crack; a dominant expansion path of fluid is obtained based on fracture expansion, a temporary plugging unit is arranged on the dominant expansion path, and simulation of in-fracture temporary plugging diversion fracturing is achieved. The influence of different reservoir parameters, natural fracture distribution and mechanical parameters, temporary plugging parameters and the like on fracture expansion behaviors can be quantitatively studied, and a basis is provided for in-fracture temporary plugging diversion fracture simulation and design optimization.

The invention provides a novel method for characterizing a complex fracture system of a deep shale gas reservoir, which comprises the following steps of: dividing a single well into a natural fracture single well, an artificial fracture single well and a natural fracture and artificial fracture coupled single well according to fracture information of the single well, generating a fracture network model diagram of the single well by adopting a Monte Carlo method in combination with a discrete fracture model, based on the permeability of a fractured low-hole shale reservoir, a single well is divided into an inner area and an outer area by adopting a radial composite model, a dual-hole medium model and a discrete fracture model are combined according to the continuity and heterogeneity of reservoir fractures, and a natural fracture, an artificial fracture and a complex fracture system with the natural fracture and the artificial fracture coupled are subjected to a single-well separation method. And carrying out characterization. The characterization method for the single well complex fracture system is formed, reservoir parameters and fracture parameters can be accurately inverted, the reliability of fracture characterization is improved, and efficient exploration and development are effectively supported.

The invention provides a method for underground water coupling simulation in a multi-scale fracture matrix system and a device thereof. The method comprises the following steps: acquiring statistical data of multi-scale fractures of a rock mass in a to-be-simulated area; generating a multi-scale fracture system based on the statistical data of the multi-scale fractures; respectively converting the small-scale discrete fracture model, the medium-scale discrete fracture model and the large-scale discrete fracture model in the multi-scale fracture system to obtain a multi-scale fracture matrix continuous medium model; and simulating water flow migration and solute migration of the rock mass through a multi-scale fracture matrix continuous medium model to obtain a water head distribution simulation diagram and a concentration distribution simulation diagram of the rock mass. By means of the method and the device, cracks of various scales in the rock mass can be simulated, the accuracy of rock mass water flow migration and solute migration simulation can be improved, and then the real state of underground water in the rock mass can be simulated more accurately.

The invention relates to a fractured reservoir CO2 oil displacement flow simulation method, in particular to a fractured reservoir CO2 oil displacement flow simulation method utilizing a neural network technology. The method comprises the following steps that a target oil reservoir is surveyed, oil reservoir geological parameters and fracture geometric parameters are collected, and a fractured oil reservoir geometric model is established; establishing a flash calculation model based on a neural network; establishing an embedded discrete crack model to describe the crack; establishing a component model to describe the CO2 oil displacement process; and combining the flash calculation model based on the neural network model with the component model, considering an embedded discrete fracture model, establishing a fractured reservoir CO2 oil displacement flow model, and performing numerical solution. According to the method, flash evaporation calculation can be rapidly and stably carried out by utilizing the advantages of the neural network, the convergence speed of calculation is improved, and meanwhile, the influence of cracks on CO2 oil displacement is accurately described.

The invention discloses a method and system for analyzing production induced stress before refracturing of a shale gas reservoir, and the method comprises the steps: building an apparent permeability model to consider complex gas flow behaviors under a multi-scale pore structure, building an embedded discrete fracture model, and coupling the flow of matrix-fracture and fracture-fracture systems; on the basis, a shale gas reservoir multi-scale flow-solid coupling horizontal well seepage model is established, and a fully implicit finite volume method is adopted for solving, so that the solving precision and efficiency are guaranteed. Therefore, the method accords with complex fracture distribution and a multi-scale flow mechanism, can truly reflect a rule of in-situ stress field change before refracturing, is used for simulating expansion of secondary hydraulic fractures, and is suitable for natural fracture development and low-porosity and low-permeability shale gas reservoirs.

The invention discloses a crack network-containing hot dry rock heat collection performance simulation method, equipment and a medium. The method comprises the following steps: establishing a hot dry rock matrix system and crack network system coupling model; establishing a flow control equation of a hot dry rock matrix system and a flow control equation of a fracture network system according to S1; establishing a heat exchange control equation of a hot dry rock matrix system and a heat exchange control equation of a fracture network system according to S1; and solving the flow control equation and the heat conduction control equation established in the S2 and the S3 through numerical discretization and coupling. By establishing an embedded discrete fracture model, a hot dry rock matrix system and a fracture network system are coupled, a dynamic model of fluid flow and heat exchange between systems is established, and the defects that an existing hot dry rock heat collection rule simulation method is limited by random natural fracture distribution and low in calculation efficiency are overcome. According to the method, a more advanced whole system flow and heat exchange model is established, and the model calculation efficiency and the engineering application scale are improved based on a discontinuous-fully implicit numerical solution method.