143 results about "Complex fracture" patented technology

The present invention belongs to the technical field of fracture network optimization in oilfield exploitation. Specifically disclosed are a method and system for optimizing complex fracture networks in shale reservoirs. The method comprises: S1, on the basis of geological-engineering bimodal data fusion, constructing a three-dimensional digital twin of heterogeneous reservoirs; S2, synchronously calculating the interactions among fluid flow, rock fracturing and proppant transport during a hydraulic fracturing process; and S3, automatically and iteratively optimizing a combination of fracturing operation parameters. By means of constructing a closed-loop system consisting of geological modeling, multi-field coupling simulation, intelligent optimization and dynamic correction, efficient design and real-time optimization of complex fracture networks in shale reservoirs are realized.

The invention discloses a shale oil and gas horizontal well layer-crossing expansion fracturing method and application. The fracturing method comprises a pre-fracturing step and a fracture forming step. The displacement of fracturing fluid used in the pre-fracturing step is gradually increased, and the displacement increasing amplitude is gradually increased; the fracture forming step comprises a four-stage reinforced temporary plugging construction step, and variable displacement temporary plugging construction is adopted when temporary plugging balls are delivered for temporary plugging construction. According to the fracturing method, the space-time form of fracture expansion is reasonably regulated and controlled, fracture diversion and reservoir matrix serious damage caused by too high viscosity of fracturing fluid are avoided while the fracture height completely penetrates through a target small layer, the problems that the fracture is excessively expanded in a non-target layer, centralized transformation and repeated transformation are conducted near a shaft and the like are solved, and the fracturing efficiency is improved. The fracture length is greatly increased, the size and the drainage area are effectively transformed, and the fracturing targets of promoting generation of complex fractures and improving the yield and the efficiency through layer-penetrating body expansion are achieved.

The invention provides a shale reservoir fracture prediction method and system based on three-dimensional full-waveform inversion and a medium, and relates to the technical field of data analysis, and the method comprises the steps: arranging a multi-channel seismic exploration instrument in a shale reservoir region, and collecting full-waveform seismic data, including longitudinal waves, transverse waves and reflected waves; performing three-dimensional full-waveform inversion based on the logging data, the geological structure map and the full-waveform seismic data to generate a shale reservoir attribute model; a multi-scale inversion strategy is constructed, fracture sensitivity analysis and fracture form dynamic prediction are carried out, and reservoir fracture distribution characteristics and reservoir fracture form characteristics are obtained; discrete fracture point connection and fracture network reconstruction are carried out, a reservoir three-dimensional fracture network model is constructed, and fracture prediction visualization display is carried out. The technical problems that in the prior art, only inference based on limited data can be provided, comprehensive capture of a complex fracture network is lacked, distribution and form of fractures cannot be comprehensively and accurately described, and reservoir analysis and mining decisions are affected are solved.

The invention provides a shale gas reservoir pressure fracture network expansion numerical simulation method, which comprises the following steps of: performing multi-layer coring scanning on a shale gas reservoir, and constructing a three-dimensional digital core model; constructing digital core flow numerical simulation by adopting a lattice Boltzmann method to obtain flow physical parameters; constructing digital rock core strain simulation by adopting a finite element method to obtain rock mechanical parameters; establishing a shale gas reservoir complex fracture network expansion mathematical model by considering a fluid-solid coupling effect, and constructing a numerical solution algorithm by combining a finite element method and a finite volume method; constructing a quantitative characterization method for the shape of the fracture network after pressing, and evaluating the size and complexity of the transformed fracture network; the method fills the gap of fracturing simulation technology research, and has the characteristics of high calculation precision, short calculation period and low cost.

The invention discloses a fractured medium equivalent permeability full-tensor calculation method based on EDFM, and the method comprises the following steps: S1, generating a random fracture, and constructing a fractured medium physical model; s2, dividing a matrix grid and a crack grid based on EDFM, and endowing basic parameters to the grids; s3, constructing a fractured medium seepage model based on EDFM; s4, solving pressure distribution in the whole computational domain by adopting a three-class boundary condition loading mode; s5, calculating pressure gradient and flow velocity distribution, and calculating average pressure gradient and average flow velocity in the whole computational domain; and S6, calculating an equivalent permeability full tensor matrix, and carrying out symmetric processing on the equivalent permeability full tensor matrix to obtain a calculation result. According to the method, the problems of low calculation efficiency and high calculation cost caused by complex fracture grid form or too many fractures in the fractured medium can be solved, the calculated equivalent permeability full tensor can well represent heterogeneity and anisotropy of the fractured medium, and technical support is provided for development of the fractured medium.

The invention discloses a generative adversarial fracture network expansion simulation system and a method thereof. The system constructs a digital twinborn model of crack propagation based on a generative adversarial network. The generator adopts a 3D convolutional neural network structure and inputs geomechanical parameter tensors to generate a three-dimensional fracture network form; a discriminator is introduced into a physical constraint module, a fracture mechanical equation is embedded into a discrimination process to serve as a regularization item, and it is ensured that a generated crack meets mechanical rationality. In the training process, a crack fractal dimension evaluation algorithm is developed, the Hausdorff fractal dimension of the generated crack network is calculated, and the Hausdorff fractal dimension is compared with the real crack network fractal dimension to serve as constraint loss. In the application of shale oil horizontal well fracturing design, the matching degree of the fracture network generated by the system and the microseism monitoring result reaches about 89%, and the distribution optimization efficiency of the proppant in the complex fracture network is improved by about 3 times.

The invention discloses a coal seam induced fracturing method. A hydraulic fracturing fluid comprises a basic aqueous phase system and induced functional particles dispersed in the basic aqueous phase system. The prepared hydraulic fracturing fluid is injected into a target stratum at the set displacement and pressure, and an initial main fracture is formed in a reservoir by means of the fluid pressure; in the process, the functional particles in the fracturing fluid enter the crack tip and the potential branch position along with the fluid and are uniformly distributed in a crack channel; along with migration of the fracturing fluid in the stratum, the inducible functional particles act under different triggering conditions, so that the fracture system is evolved into a multi-direction and multi-branch fracture network from a single main fracture, and the transformation volume and the reservoir permeability are increased. Expansion or reaction can be triggered in the fracture, so that stress concentration is generated locally, secondary fracture formation is induced, a complex fracture network is constructed, and reservoir permeability is improved.

A hydraulic pulse-type soluble segmented acid fracturing slide sleeve and a pulse acid fracturing construction method. The slide sleeve comprises a slide sleeve outer cylinder (1) and a rotary valve assembly, and flow-passing holes (101) are formed on the slide sleeve outer cylinder (1); the rotary valve assembly comprises a valve core (2) and a valve ball (13), and the valve ball (13) can block a passage (203); a flow guide channel (206) and flow splitting channels (207) are formed between the outer wall of the valve core (2) and the inner wall of the slide sleeve outer cylinder (1); the slide sleeve outer cylinder (1) has a first position and a second position in the axial direction; when the valve core (2) is located at the first position, the outer wall of the valve core (2) blocks the flow-passing holes (101); an acid fracturing working fluid flowing through the flow guide channel (206) can push the valve core (2) to move from the first position to the second position along the slide sleeve outer cylinder (1), and push the valve core (2) to continuously rotate at the second position, so that the flow splitting channels (207) are alternately communicated with the flow-passing holes (101), the acid fracturing working fluid is discharged from the flow-passing holes as hydraulic pulses, hydraulic pulses with a proper frequency can be excited at the bottom of a well, energy attenuation is reduced, and the formation of a complex fracture network is promoted in a stratum.

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 provides a fracture detection method based on gridding and a DBSCAN clustering algorithm. The fracture detection method comprises the steps of obtaining post-stack seismic data as input data of a subsequent calculation step; carrying out fracture sensitive attribute calculation on the post-stack seismic data; clustering analysis is carried out on fracture detection attributes through a DBSCAN algorithm so as to realize automatic tracking of fracture detection results, on this basis, through gridding processing, a reasonable threshold value is set for tracked fracture data according to geometric topology information such as an inclination angle, an inclination angle and a length in combination with prior geological knowledge, cleaning of the fracture detection results is realized, and the fracture detection results are cleared. And finally, a fracture detection data body with high precision and high signal-to-noise ratio is obtained. The method is suitable for the seismic data processing field with a complex fracture system and a low seismic data signal-to-noise ratio. Compared with the prior art, the method has the advantages that the finally obtained fracture detection result is high in signal-to-noise ratio, high in resolution, obvious in linear feature, good in continuity, high in interpretability and better in conformity with geological knowledge of a work area.

The invention relates to a geological fracture recognition method based on multi-source geophysical data and a computer system, and solves the problem of high-precision recognition of tiny fractures and complex fracture zones. The method comprises the following steps: acquiring gravitational field model data, full-tensor gravity gradient data and aeromagnetic data of a target area, and carrying out gridding processing, pole conversion processing and edge expansion preprocessing on the data; performing boundary identification calculation on the preprocessed data by adopting a traditional physical field multi-derivative algorithm to generate a first group of boundary information A; carrying out boundary recognition calculation on the preprocessed data by adopting a gravity and full-tensor gravity gradient combined derivative algorithm (an enhanced total horizontal gradient derivative algorithm, a combined derivative algorithm and a combined oblique derivative algorithm) to generate a second group of boundary information B, and carrying out boundary recognition calculation on the preprocessed data by adopting an image edge detection algorithm to generate a second group of boundary information B; generating a third group of boundary information C; and carrying out weighted fusion on the three groups of boundary information to obtain a final fracture identification result.

The invention relates to the technical field of oil and gas reservoir development and geological modeling, and discloses a multi-scale factor constraint-based tectonic network fracture modeling method, which comprises the following steps of: synthesizing a Riemannian metric tensor field on the basis of earthquake, logging and geomechanics data, and defining non-Euclidean distance cost of a fracture expanded in an anisotropic medium; initial seed points are screened according to the elastic strain energy density, and initial growth potential energy in a limited range is distributed; solving the eikonal equation by using an anisotropic fast marching algorithm to carry out wavefront competitive growth, and dividing a grid region into generalized Voronoi units; identifying a wavefront contact interface, and extracting gradient features to judge a fusion or truncation type so as to establish fracture topological connection; and finally, tracking a geodesic line path along an anti-gradient direction to generate a three-dimensional discrete fracture network. According to the method, macro and micro constraints are unified through Riemannian geometry, clear physical significance is given to the fracture by utilizing an energy mechanism, and automatic and accurate construction of the complex fracture network topology structure is realized.

The invention discloses a tight gas reservoir rock compressibility evaluation method and system, computer equipment and a medium, and relates to the technical field of petroleum and natural gas development. The method comprises the following steps: testing to obtain rock sample parameters of a target reservoir rock sample; on the basis of the rock sample parameters of the target reservoir rock sample, the rock natural fracture crushing degree is obtained through calculation; based on the rock sample parameters of the target reservoir rock sample, obtaining the potential of reservoir transformation to form a fracture network; and according to the natural fracture crushing degree of the rock and the potential of forming a fracture network through reservoir transformation, calculating to obtain a rock compressibility index which is used for evaluating the rock compressibility. The rock compressibility is dynamically evaluated by comprehensively considering the natural fracture crushing degree and whether the potential of forming a complex fracture network through reservoir transformation can obtain high productivity or not, and technical support is provided for tight oil and gas exploration and development.

The invention belongs to the technical field of rock physics and geophysics, and discloses a complex fracture anisotropic elastic parameter characterization method and system.The method comprises the steps that an outcrop picture of a fracture-karst geologic body is processed, a complex fracture model is obtained, and the fracture density and the fracture direction of the complex fracture model are calculated; a new Biot consolidation equation is constructed; designing an oscillation relaxation experiment; the complex fracture model is simulated, corresponding boundary conditions are given, and stress and strain fields of the complex fracture model are obtained through calculation; establishing a damage function, and substituting the stress and strain field of the complex crack model to solve the damage function to obtain elastic parameters of the complex crack model corresponding to a single frequency; different frequencies are given to realize calculation of anisotropic elastic parameters of the complex fracture. According to the invention, anisotropic elastic characterization of the complex crack rock can be realized more effectively; according to the method, the restrictive problem of conventional rock physical equivalent modeling and conventional numerical simulation estimation of the elastic parameters is effectively solved.

The invention provides an oil reservoir production optimization method considering a complex fracture network. The oil reservoir production optimization method considering the complex fracture network comprises the steps that 1, an oil reservoir is divided into two areas according to the development scale of fractures in the oil reservoir; step 2, respectively establishing a single pipeline model and a dual-medium model for the divided areas, and solving the models by dividing grids on the pipeline; 3, performing historical fitting on the observation value and the simulation value by means of a set multi-smooth data assimilation algorithm to obtain an optimized model; and step 4, optimizing the injection-production quantity of each well by using the optimized model and taking the economic net present value of the oil reservoir as a target function. The oil reservoir production optimization method considering the complex fracture network has excellent performance in the aspect of improving the crude oil recovery efficiency, and a remarkable optimization effect is achieved. The method can effectively deal with the complex fracture network existing in the oil reservoir, improve the production efficiency and improve the economic benefit of the oil field to the maximum extent.

The invention provides a femoral trochanter fracture type classification method. The method comprises the following steps: preprocessing an image data set; performing feature extraction on the image data by using an SIFT algorithm; performing feature extraction on the image data by using a DenseNet model; fusing the key point features and the deep features; and classifying the fused features. The method has the beneficial effects that the SIFT algorithm is combined with the DenseNet deep learning model, SIFT focuses on extracting local features in the image and has strong rotation and zoom invariance, and DenseNet captures more complex global features through dense connection characteristics, so that the overall structure and context information of the image are understood; according to the weighted fusion strategy, the model can dynamically adjust the weights of different features according to data characteristics and training stages, the adaptability of the model to different types of fracture features is enhanced, the model can make more accurate classification judgment through reasonable combination of local and global features no matter simple fracture or complex fracture, and the classification accuracy is improved. And the generalization ability of the model is improved.

The invention discloses a design method capable of giving consideration to both toughening and crack path controllability for a brittle material, and belongs to the technical field of fracture mechanics and artificial intelligence crossing, and the method comprises the steps: employing an input coding method based on space-response double-domain fusion to carry out feature extraction; introducing a channel attention mechanism to perform weighted fusion on the extracted double-domain features, and generating prediction results for different key tasks; evaluating the reliability of a prediction result by adopting a phase field verification and closed-loop adaptive optimization mode, and carrying out iterative training and optimization on the neural network; and taking the optimized neural network as a fitness evaluation function of double-target genetic optimization, and performing multi-target optimization on defect generation parameters. According to the invention, through fusion of the spatial domain and the response domain, geometric morphology and dynamic response characteristics are cooperatively extracted, and the prediction precision of complex fracture behaviors is improved; through non-dominated sorting multi-objective optimization under physical constraints, a high-toughness and path-controllable optimal solution is output, and brittle materials are pushed to cross an active controllable fracture design.

The invention discloses a complex fractured rock mass physical reconstruction method based on deep learning, and belongs to the technical field of rock mass sample preparation. The method comprises the following steps: S1, quantifying rock mass characteristics by adopting a mechanical property target value and a fracture structure feature vector, and establishing a database; s2, constructing a multi-task deep neural network model based on an attention mechanism, and training the model; s3, determining the mechanical property and the fracture structure of a rock sample needing to be prepared, and acquiring corresponding 3D printing process parameters by adopting the trained attention mechanism-based multi-task deep neural network model; and according to the obtained 3D printing process parameters, a rock sample with required mechanical properties and fracture structures is prepared by adopting a 3D printing method. According to the method, mechanical property similarity and fracture structure fidelity are balanced, the high structural consistency of the prepared sample and the primary rock mass is ensured, the preparation process is repeatable, and a reliable sample is provided for a rock mechanical test.

The application discloses a kind of acquisition methods, devices, media and electronic equipment of complex fracture conductivity, and its method includes: (A) extracting the specific form of complex fracture formed in stratum by hydraulic fracturing, calculating the average filling concentration of proppant in complex fracture;(B) complex fracture is divided into multiple simple straight fracture units, and the closure stress suffered by each fracture unit in stratum is calculated;(C) carry out simple straight fracture conductivity experiment, obtain the change curve of fracture conductivity with closure stress, and the relationship between fracture conductivity and closure stress is fitted;(D) the fracture conductivity corresponding to each fracture unit is calculated;(E) the fracture conductivity of each fracture unit is used to calculate the conductivity of the whole complex fracture.The application principle is reliable, simple to operate, and has strong practicability, can more accurately obtain the conductivity of complex fracture formed by hydraulic fracturing, and then provide effective guidance for hydraulic fracturing construction effect evaluation.

The invention provides a method and system for calculating the topological connectivity of a two-dimensional discrete fracture network containing n-type nodes, and the method comprises the steps: carrying out the binarization processing of an original fracture image of a rock surface, and generating a fracture binary image; extracting each crack region from the crack binary image based on connected domain analysis; extracting an outer contour pixel point set and a central axis point set of any crack region; an intersection point cluster is extracted from the central axis point set, and an effective extension point, located on the central axis, of each intersection point is obtained; determining the node type of each intersection point according to the number of the effective extension points of each intersection point; and calculating connectivity parameters of any crack region according to the node type of each intersection point of any crack region. Through the method, the node types in the two-dimensional discrete fracture network can be automatically identified, accurate quantization of connectivity is realized in combination with graph theory parameters, and the analysis precision and efficiency of the complex fracture network are remarkably improved.

The invention relates to a phase change clay fracture performance and failure characteristic test device, a prefabricated crack soil beam test piece, a servo motor, a sensor and a camera unit are arranged on a three-point / four-point bending moment loading frame, and the servo motor and the sensor are connected with a data acquisition unit. The invention also relates to a phase change clay fracture performance and failure characteristic test method. According to the invention, the compressive fracture process of the phase-change clay can be truly simulated, the fracture performance and damage characteristics of the phase-change clay in various complex fracture modes (including I-type, II-type and I-II-type fracture modes) can be accurately and reliably measured, and a premise can be provided for research of the fracture characteristics of the phase-change clay and analysis of core wall fracture damage and hydraulic fracture problems.

The invention discloses a calculation method of a rock mass fracture network seepage field containing a complex fracture form, and relates to the field of geotechnical engineering. The method comprises the following steps: for each node in a rock mass fracture network, determining a source-sink item at the node based on the flow of a plurality of fracture units connected with the node; substituting the source sink item at the node and the equivalent permeability coefficient matrix into an overall matrix equation of fracture network seepage for solving to obtain a pressure head value of the node; the overall matrix equation is obtained by assembling unit seepage matrix equations of all nodes in the rock mass fracture network; in the construction process of the fracture seepage unit equation, the influence of the on-way resistance coefficient on the equivalent seepage flow velocity of the fracture in the complex wall surface form and the influence of the local resistance coefficient on the equivalent seepage flow velocity of the fracture in the complex wall surface form are considered; and determining the pressure head values of all nodes in the rock mass fracture network as a rock mass fracture network seepage field. The method can improve the calculation precision of the fracture network seepage field.

The invention discloses a method and a device for predicting the productivity of a directional fracturing horizontal well of a complex fracture network shale gas reservoir. The method comprises the following steps: respectively establishing corresponding relations between shale gas viscosity, a compression factor, a compression coefficient and reservoir permeability and reservoir pressure; on the basis of the matrix grid model, hydraulic fractures are embedded by adopting a determined modeling method, and natural fractures are embedded by adopting a random modeling method; according to the fact that shale gas follows the Langmuir adsorption law in a matrix and follows the Darcy flow law in a crack, mass conservation equations of the matrix and the crack are established respectively; flow relations between adjacent matrix grids, between fracture grids, between matrixes and fracture grids and between crossed fracture grids are established respectively, and a matrix equation set of the horizontal well is obtained in combination with a Peaeman well equation; and solving to obtain the productivity data of the horizontal well. According to the method, reasonable productivity prediction can be carried out on the shale gas reservoir directional fracturing horizontal well under the constraint of the complex fracture network.

The invention discloses a multi-channel injection system and method for an ultra-large rock core hydraulic fracturing experiment. The system comprises a three-dimensional injection array module, a modular injection panel, a variable impedance regulation and control unit, a dual-medium consistency injection module and a fluid-solid coupling compensation control unit. The method comprises the following steps: constructing a three-dimensional matrix type injection network, preparing sand-carrying fluid with uniform concentration, configuring initial fluid impedance to realize multi-channel flow matching, starting synchronous injection, monitoring pressure and stress signals in real time, and dynamically adjusting the impedance of each channel to compensate the heterogeneity of the rock core. And finally, a uniform and stable volumetric pressure field is formed and maintained in the ultra-large rock core, and meanwhile, the concentration deviation of the sand-carrying fluid between the channels is controlled within a preset threshold value. The technical problems that a pressure field in a large-scale rock core is not uniform, proppant conveying is not stable and multi-channel interference is not stable are solved, and the method is suitable for complex crack expansion and proppant laying mechanism research.

The invention discloses a magneto-rheological effect-based deep coal seam waterless fracturing yield increasing device and method.The magneto-rheological effect-based deep coal seam waterless fracturing yield increasing device comprises a fluid magnetization pretreatment tank, a directional fracture forming assembly, a monitoring assembly and a control terminal, and the directional fracture forming assembly comprises a proppant storage tank, a fluid mixing tank, a main pipeline, a plurality of magnetic field generators, a plurality of nozzles and a temporary plugging ball injector; the fluid mixing tank is connected with the fluid magnetization pretreatment tank and the proppant storage tank, the main pipeline comprises a longitudinal section pipeline connected with the fluid mixing tank and a horizontal section pipeline connected with the gas storage tank, the spray head is inserted into the side wall of the horizontal section pipeline, and the magnetic field generator is arranged in the horizontal section pipeline; the monitoring assembly comprises a magneto-dependent sensor and a micro-seismic monitor, the magneto-dependent sensor is arranged on the outer wall of the horizontal casing pipe, and the micro-seismic monitor is arranged in the horizontal casing pipe; the control terminal is electrically connected with the temporary blocking ball injector, the magnetic field generator and the monitoring assembly; in this way, the rock breaking efficiency is improved, water is not needed, a high-diversion complex fracture network system is formed, and it is ensured that fracture expansion is accurate and controllable.

The present invention provides a method and apparatus for numerically discretizing complex fractures in shale reservoir fracturing. The method comprises loading an original numerical simulation background matrix grid and fracture polygons, parsing the fracture polygons, recording the fracture polygon coordinates, removing duplicate points from the fracture polygon coordinates, and characterizing the fracture polygons as a topologically consistent geometric structure based on the fracture polygon coordinates without duplicate points. Based on the topologically consistent geometric structure, the method calculates the fracture polygons intercepted by the background matrix grid when each fracture polygon is embedded in the background matrix grid. Connected fracture polygons within the background matrix grid are identified and grouped, and the conductivity between the background matrix grid and connected fracture polygons, and between connected fracture polygons and connected fracture polygons, is calculated. When calculating the conductivity parameters of embedded fractures, the method merges and divides fractures based on their connectivity, thereby improving the accuracy and efficiency of the calculation of non-connected fractures within the background grid.

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 discloses a nuclear fuel particle fracture analogue simulation method based on a fracture phase field method, belongs to the technical field of nuclear fuel particle fracture simulation, and aims to solve the problems that the research efficiency is low and the application range of a numerical model is limited when a traditional method is used for a complex fracture condition. The method comprises the steps of building a phase field model, inputting material attribute parameters, setting boundary conditions of nuclear fuel particles, adding irreversibility constraints into an evolution equation of the phase field model, setting differentiated analogue simulation step lengths and outputting simulation results. Spatial distribution of phase field variables is used as characterization of a damaged area and a crack form, and real-time tracking of a crack tip position and an expansion path is not needed; for scenes such as multi-particle intersection cracks, branch cracks and irregular cracks which are difficult to process by a traditional method, accurate simulation can be realized only through phase field variable evolution without adjusting a grid or a calculation model.

The invention relates to the technical field of oil and gas exploitation, and particularly discloses an unconventional fracturing complex fracture network expansion simulation method based on uncertainty modeling, and the method comprises the steps: calculating the half length of a fracture based on perforation reservoir parameters obtained through logging and other methods in combination with an analytical fracture expansion simulation method; carrying out complex fracture network simulation by taking the fractal probability as a constraint and combining with a fracture growth algorithm with fractal probability random distribution characteristics to obtain reservoir complex fracture network form distribution; and finally, fracturing construction monitoring pump pressure fitting is performed based on an intelligent algorithm, the volume and form of the complex fracture network are inversely corrected, and real-time expansion simulation of the complex fracture network in the fracturing process is realized. According to the method, the complex branch fracture form can be depicted more finely, meanwhile, the calculation speed is high, and real-time simulation of the complex fracture net form in the fracturing process can be achieved; the method achieves the efficient and accurate simulation of the fracture form under the condition that the crustal stress of the reservoir is not clearly known, and provides an effective technical means for the fracturing construction design of the unconventional reservoir.

The invention discloses a sand adding pump injection parameter optimization design method and device. The method comprises the following steps: simulating a complex fracture form to obtain a digital fracture model; based on the digital crack model, simulating the laying forms of the propping agent under a plurality of different conditions contained in the orthogonal experimental simulation scheme to obtain corresponding laying concentrations; the plurality of different conditions are a plurality of different sand adding parameter and pump injection parameter combinations; according to the laying concentrations under the multiple different conditions and the corrected flow conductivity calculation model, flow conductivity values under the multiple different conditions are calculated respectively; inputting the distribution results of the flow conductivity values under the plurality of different conditions into a productivity prediction model, and predicting the yields in a preset time period under the plurality of different conditions; and determining a combination of the sand adding parameter and the pump injection parameter corresponding to the highest yield as an optimization design result. The invention provides a reasonable sand adding pump injection optimization design method, and effective guidance is provided for proppant pump injection scheme design of complex cracks.