10 results about "Discrete fracture model" patented technology

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 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 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.

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 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.

The present application belongs to the technical field of oil and gas reservoir energy development, and discloses a kind of stereoscopic injection-production well pattern construction method based on multi-objective algorithm.Effectively solve the problem that the existing potential evaluation is only based on single index, which makes it difficult to effectively use the potential area divided.The method includes: proposing fault inner core, fault outer core, fracture development dense belt and secondary fracture belt;using reservoir engineering method and numerical simulation streamline method, analyzing interwell connectivity of reservoir unit;based on embedded discrete fracture model, analyzing remaining oil distribution pattern under the control of core belt structure;combining remaining oil producing potential, displacement power, flow capacity, connectivity and reserve abundance, constructing multi-parameter comprehensive evaluation system;for oil reservoirs with or without bottom water, forming stereoscopic injection-production well pattern construction technology;based on multi-objective optimization algorithm, taking three-dimensional collaborative optimization of recovery efficiency, well-controlled reserves and net present value as the core, constructing efficient well location deployment technology in different fracture zones.

The application discloses a shale gas supercritical carbon dioxide fracturing and production integrated simulation method and belongs to the fracturing technical field of petroleum engineering. The method comprises the following steps: S1, setting a fracture potential path based on natural fractures and in-situ stress, generating a fracture grid from the fracture potential path, and performing value assignment on the fracture grid; S2, simulating fracture deformation and fracture expansion by adopting a plane three-dimensional displacement discontinuity method, combining an embedded discrete fracture model and a component model to represent matrix-fracture fluid exchange, and performing supercritical carbon dioxide fracturing simulation through iterative coupling; and S3, performing production simulation with a pressure field and component distribution after fracturing simulation as initial conditions according to the opening of the fractures after fracturing simulation and the permeability calculated from the opening. The application can more accurately realize supercritical carbon dioxide fracturing and production integrated simulation, can provide technical support for tracking the migration path of carbon dioxide in the fracturing-well killing-production whole cycle and evaluating the feasibility of carbon dioxide storage after fracturing.