200 results about "Fracture propagation" patented technology

The present invention relates to the technical field of oil and natural gas exploitation, and discloses a real-time monitoring and intelligent control system for hydraulic fracturing cracks in oil reservoirs, including: a real-time monitoring module, which is used to collect crack geometric morphology parameters and construction operation parameters in real time during crack expansion; a nonlinear modeling module, which is connected to the real-time monitoring module, and is used to construct a nonlinear dynamic model of crack expansion according to the collected crack expansion parameters and construction operation parameters, and output a predicted value of crack morphology; an optimization control module, which is connected to the nonlinear modeling module, and is used to calculate the optimized construction parameters according to the nonlinear dynamic model, including injection pressure, injection flow rate and viscosity of fracturing fluid. The present invention realizes precise control of crack expansion, intelligent optimization of construction parameters and efficiency improvement through the closed-loop linkage of real-time monitoring, nonlinear modeling, optimization control and feedback execution.

The invention relates to the technical field of oil and gas field development, and discloses an ultra-large type true triaxial hydraulic fracturing fracture evolution path prediction method and system.The prediction method comprises the steps that a coupling geomechanical model integrating microscopic, macroscopic and wellbore flow scales is constructed; initializing the model and performing crack initial expansion simulation; collecting construction data in real time, and dynamically optimizing model parameters through a data assimilation algorithm; performing fracture evolution advanced prediction by using the updated model; and generating an optimization decision based on the prediction result and feeding back to the construction site. According to the method, fusion of a multi-scale physical mechanism and real-time dynamic prediction is realized, and accurate prediction and active control can be performed on crack expansion under the ultra-large true triaxial condition.

The invention relates to the technical field of data acquisition and data analysis, in particular to a hydraulic fracturing test crack propagation monitoring system which comprises a monitoring system and is used for monitoring crack propagation behaviors in the hydraulic fracturing process in real time. Constant or dynamically changing confining pressure and axial pressure are provided; the pore pressure dynamic regulation and control unit is used for accurately controlling the injection pressure, flow and saturation of fracturing fluid and simulating fracture propagation behaviors under different seepage conditions; the multi-physics field sensing monitoring network unit is used for collecting strain, sound wave signals and a surface displacement field in the crack expansion process in real time; full-scale monitoring of rock fracture propagation is realized, an influence mechanism of pore pressure and time effect on fracture evolution is disclosed, an accurate prediction means is provided for shale gas development and deep engineering, and the fracturing effect and engineering safety are remarkably improved.

The invention discloses a method for calculating the migration of a proppant in a horizontal well fracturing crack and the global flow conductivity of the crack, and relates to the field of unconventional oil and gas reservoir yield increase renovation, and the method comprises the following steps: (1) establishing a reservoir geologic model according to on-site logging exploration data; (2) establishing a hydraulic fracturing crack propagation fluid-solid coupling model; (3) establishing a horizontal well fracturing inter-cluster flow distribution model; (4) constructing a propping agent migration liquid-solid two-phase flow model in the hydraulic fracture; (5) solving the fluid-solid coupling model and the proppant migration model through loop iteration, and predicting the concentration distribution of the proppant in the hydraulic fracture; and (6) on the basis of the crack width and the proppant distribution result, calculating the hydraulic fracturing crack global flow conductivity. According to the method, the proppant migration model is solved by adopting a high-order discrete format, dynamic coupling simulation of hydraulic fracture propagation and proppant migration under the mine field scale is realized, the global flow conductivity of the hydraulic fracture is calculated, and reference is provided for evaluation and optimization of unconventional reservoir fracturing transformation.

The invention discloses a geological modeling, crack propagation and fluid-solid coupling production prediction integrated evaluation method, and relates to the field of multiple technologies, and the method comprises the steps: constructing a three-dimensional geological model of a deep shale gas reservoir; according to the construction model, the attribute model, the three-dimensional ground stress model and the rock mechanical parameter model, a hydraulic fracture model is constructed; based on the hydraulic fracture model and the three-dimensional geological model of the deep shale gas reservoir, establishing a fluid-solid coupling productivity simulation mathematical model of the deep shale gas reservoir; according to the fluid-solid coupling productivity simulation mathematical model of the deep shale gas reservoir, the fractured horizontal well yield of the shale gas reservoir is predicted, and a prediction result is comprehensively evaluated and optimized. According to the method, multiple links of geological modeling, fracture propagation simulation, fluid-solid coupling production prediction and the like are integrated, and the geological characteristics of the gas reservoir, the fracture propagation rule and the interaction between fluid flow and solid deformation are comprehensively considered, so that comprehensive evaluation and optimal development of the deep shale gas reservoir are realized.

The invention relates to the technical field of rock mechanics and petroleum and natural gas engineering, and particularly discloses a hydraulic fracture fracturing monitoring system, method and device based on optical fiber monitoring, and the system comprises a hydraulic fracturing simulation platform which is used for applying three-dimensional stress to a hydraulic fracturing test piece so as to simulate a stratum stress environment; the fracturing fluid injection device is used for injecting pre-prepared fracturing fluid into the test piece, so that a crack in the test piece expands; a plurality of strain sensor groups embedded in the test piece in the preparation process of the test piece; the optical fiber sensing demodulation device is used for collecting strain data detected by the plurality of strain sensor groups; and the data processing device is in communication connection with the optical fiber sensing demodulation device and is used for acquiring the strain data and processing the strain data so as to determine real-time state data of crack expansion in the test piece. According to the scheme, the fracture strain can be monitored in real time, and the accuracy and controllability of the hydraulic fracturing process are improved.

Providing a method for assessing the impact of fragile structures on large-scale fracturing in deep thermal reservoirs "Solution: Based on a precise depiction of the fragile structure of the formation and a study of its mechanical properties, the spatial distribution of the structure is determined, well locations and networks are arranged, fracturing zones are selected, and the fracturing suitability of the formation is comprehensively evaluated. Furthermore, a thermal-fluid-solid coupled damage model and a thermal-fluid-solid-chemical coupled damage model are established to study the activation conditions of the original fragile structure surface, and the fluid filtration characteristics of the structure and the maximum discharge volume that can be safely fractured are evaluated. Based on this, triaxial fracturing physical simulations and numerical simulations are carried out to clarify the influence laws of the fragile structure surface on the expansion and seepage flow of fracture cracks, and to clarify the influence mechanism of the fragile structure on large-scale fracturing of the formation under high temperature and pressure conditions."

The invention discloses a high-temperature and high-pressure true triaxial fracturing physical simulation experiment system, which comprises a heating and temperature control module, a loading module, a pump injection module, a sample loading module and a monitoring module, and can meet the test conditions of a high-temperature true triaxial fracturing physical simulation test through organic combination. The heating and temperature control module can be used for heating a sample to reach a formation temperature condition, and the loading module can be used for applying non-uniform ground stress to the sample; the multi-crack expansion pump injection module can be used for performing fracturing physical simulation on the sample, i.e., high-pressure fluid drives crack expansion, and monitoring the pressure and the flow in each crack in the expansion process; the crack propagation monitoring module monitors the fracture, fracture and crack propagation of the sample through acoustic, optical and other monitoring methods. Several main functional modules are organically combined to ensure that the test meets the requirements of physical simulation of high-temperature and high-pressure geological conditions of strata, physical simulation of crack propagation and characterization of crack propagation.

The invention provides an analysis method for multi-cluster fracturing crossing in a horizontal well section of a sand shale reservoir, which comprises the following steps of: based on a boundary element theory, considering three-dimensional fracture stress interference and flow distribution of each cluster, and establishing a full-three-dimensional fracture propagation numerical model of segmented multi-cluster fracturing stress interference and flow distribution of a tight gas horizontal well; coupling the wellbore flow model and the crack propagation numerical model through bottom hole pressure to obtain a coupling model; based on a three-dimensional boundary element theory, aiming at the coupling model, discretizing different fracture forms into rectangular units, and establishing a three-dimensional boundary element stress interference calculation model through a superposition principle; under the condition that geological factors are kept constant, the influence of different construction parameters on crack propagation and layer crossing behaviors is analyzed, a crack layer crossing main control factor is obtained, and the conditions and boundaries of segmented multi-cluster fracturing layer crossing of the sand-mud interbed horizontal well are determined. The method provides a basis for optimization of crack parameters and construction parameters.

The invention discloses a multi-factor coupling action slope dangerous rock mass instability starting speed determination method which comprises the following steps: establishing a dangerous rock mass generalization mechanical model, simplifying a dangerous rock mass main control structural plane into two parts, namely a through section and a non-through main control structural plane, and controlling dangerous rock mass instability damage by a rock mass corresponding to the dangerous rock mass main control structural plane; carrying out stress analysis on the dangerous rock mass and the locking section rock mass based on the external load effect and the generalized mechanical model of the dangerous rock mass; the external load effect comprises horizontal and vertical earthquake force, frost heaving force, fracture water pressure or excess pore water pressure; determining elastic strain energy released by potential energy reduction in crack propagation of the main control structural plane of the dangerous rock mass based on a multi-factor coupling effect; and on the basis of the assumption that elastic strain energy released by reduction of potential energy in crack propagation of the main control structural plane of the dangerous rock mass is instantaneously released and converted into kinetic energy of dangerous rock mass movement, the instability starting speed of slope dangerous rock mass severe movement under the multi-factor coupling effect is determined. The invention further discloses a system, electronic equipment and a computer readable storage medium.

A method involves propagating hydraulic fractures in a reservoir. Such method includes creating a low pressure region in an attractor well. The attractor well is proximate to an area in which hydraulic fractures are desired. The method also includes initiating a hydraulic fracturing operation at a treatment well. The hydraulic fracturing operation is initiated so that a fracture network created by the hydraulic fracturing operation is drawn to propagate toward the low pressure region of the attractor well.

The invention discloses an early warning method, system and terminal based on a fault instability evaluation model, and the method comprises the steps: obtaining crack data collected by a plurality of sensors, carrying out the crack propagation analysis of a rock according to the crack data, and obtaining the comprehensive crack multi-modal data; inputting the fracture multi-modal data into a fault instability evaluation model, and coupling the fracture multi-modal data by the fault instability evaluation model to generate predicted fracture parameters; and when the predicted crack parameter reaches a target early warning threshold, matching a corresponding early warning level according to the predicted crack parameter to obtain a target early warning level, and taking a corresponding response measure according to the target early warning level. According to sensor data, cracks are analyzed, multi-modal data are generated, the instability risk is evaluated, the early warning level is matched, corresponding response measures are taken, fracturing related parameters are rapidly adjusted, valuable data resources are provided, and potential risks such as resource consumption or geological disaster aggravation caused by excessive fracturing are avoided.

The invention provides a numerical simulation method and system based on rock mass fracture extension and seepage coupling, and belongs to the field of rock mechanics. Rock is regarded as a set composed of particles and mechanical contact between the particles, and a triangulation network is constructed based on the circle center of each particle; according to the geometrical characteristics of the triangulation network, a seepage pipeline network containing the interior and the periphery is built, and network nodes and boundary nodes are determined; calculating the permeability coefficient according to the particle positions on the two sides of the pipeline, and forming a penetrating seepage channel and fracture network by taking the pipeline which is not 0 and penetrates through and is connected with boundary nodes as a passage pipeline; and constructing a flow conservation equation set based on network nodes, solving pore pressure by using a Jacobian iteration method, calculating fracture pressure, and applying the fracture pressure to the model to realize coupling of a stress field and a seepage field. According to the method, the advantages of particle discrete elements in calculation of rock mass fracture extension and the advantages of a pipeline network method in calculation of fracture seepage are fully exerted, and accurate simulation of rock mass fracture initiation extension, seepage channel recognition and seepage field calculation is achieved.

The invention discloses a method, a device and equipment for determining fracturing parameters. The method comprises the following steps: acquiring historical geological physical property data, historical engineering data and historical production data of a historical reservoir; constructing a crack propagation model, and determining crack form data and geological change information of the historical reservoir based on the crack propagation model, the historical geological physical property data and the historical engineering data; taking historical geological physical property data, historical engineering data, historical production data, geological change information and fracture form data of the historical reservoir as training data, and training to obtain an oil and gas productivity calculation model; and constructing a multi-target optimization model based on the oil and gas productivity calculation model, a preset cost calculation model and the target geological physical property parameters of the target reservoir, and performing optimization solution on the multi-target optimization model to obtain fracturing construction parameters of the target reservoir. By means of the method, more accurate and reliable fracturing construction parameters can be obtained, and fine design of fracturing well completion parameters is achieved.

The invention relates to the technical field of geothermal development, and discloses a multi-source information fusion deep fracture network description and three-dimensional reconstruction method, which comprises the following steps: S1, carrying out fusion analysis on surface dominant fractures and deep hidden fractures; s2, determining a rock fracture mechanism by using a laboratory method; s3, fracture parameters are obtained after engineering fracturing; s4, establishing a multi-field coupled fracture expansion model to describe a deep reservoir fracture network; and S5, carrying out model verification. According to the invention, by integrating geological data of different scales and types, the integrity and accuracy of fracture network description are improved. And a rock fracture mechanism is researched, and the accuracy of fracture network formation is determined from the aspect of mechanical causes. In addition, three-dimensional visualization of the crack network is realized, and visual crack network structure representation is provided. The method provided by the invention is simple, the depicting precision is improved by a comprehensive method, and the cost can be reduced.

The invention provides a hydraulic fracturing crack propagation simulation method and device and electronic equipment, and the method comprises the steps: obtaining the ground stress field distribution of each fracturing section through a geomechanical model according to the geological parameters, logging interpretation and rock mechanics experiment data of a target area fracturing section; utilizing an induced stress field model to simulate induced stress distribution of each fracturing section; obtaining comprehensive crustal stress field distribution according to the crustal stress field distribution and the induced stress distribution; the theoretical crack initiation pressure of each perforation cluster of each fracturing section is calculated according to the comprehensive crustal stress field distribution by means of a perforation cluster crack pressure model, perforation cluster crack initiation data of each fracturing section are determined according to the theoretical crack initiation pressure and the actual crack pressure, and the perforation cluster crack initiation data comprise the perforation cluster crack initiation state and the perforation cluster crack initiation number; and utilizing the multi-cluster crack propagation model to obtain a crack propagation trajectory simulation result according to perforation cluster crack initiation data and an actual pump injection program. According to the method and the device, hydraulic fracture expansion of segmented multi-cluster fracturing can be accurately simulated.

The invention relates to the technical field of oil field reservoir research, in particular to a fracturing fracture imaging physical simulation method and system combined with non-uniform contact electrodes, and the method comprises the steps: carrying out the resistance modal detection at the current time step through a low-frequency excitation signal in the fracture propagation simulation process, and obtaining a corresponding electric signal; obtaining a conductive fluid distribution result of the rock core fracturing test piece at the current time step by using the conductive fluid distribution inversion model; and fitting and comparing the electric field distribution result of the current time step with the conductive fluid distribution result of the current time step, and outputting the fracture parameters and the conductive fluid distribution result of the rock core fracturing test piece at the current time step based on the fitting and comparison result. According to the method, the electrical property change caused by the natural fracture and the fluid contained in the natural fracture is directly sensed in situ, the electrical signal is acquired, the response delay is reduced, the conductive fluid distribution inversion model is constructed by combining prior knowledge and deep learning, and the precision and reliability of conductive fluid distribution inversion are effectively improved.

The invention provides a stratified reservoir lamination fracture high-crossing evaluation method and device, and relates to the technical field of oil-gas exploration, and the method comprises the steps: carrying out the combined analysis of a geomechanical model based on a target position of a research area, a first fracture propagation analysis result and a second fracture propagation analysis result, and obtaining a first fracture propagation analysis result and a second fracture propagation analysis result; determining conditions of crack induced bedding opening and crossing expansion under different reservoir and interlayer stress differences and interlayer thicknesses, and drawing a crack height crossing evaluation chart corresponding to the target position by taking the reservoir and interlayer stress differences and the interlayer thicknesses as two-dimensional coordinate axes; and performing layer crossing evaluation before fracturing construction of the to-be-built production block by using the seam height layer crossing evaluation chart. According to the method, the fracture height crossing evaluation chart is determined by combining the formation mechanical characterization, the fracture propagation physical simulation experiment and the multi-cluster fracturing fracture propagation numerical simulation experiment in the horizontal well, then the crossing evaluation of the to-be-built production block is carried out, and the post-fracturing production capacity, the overall production effect of the reservoir and the overall development benefit of the stratified reservoir are improved.

The embodiment of the invention provides a double-sweet-spot prediction method and prediction device for a geological reservoir, and the method comprises the steps: obtaining a plurality of to-be-analyzed regions according to the three-dimensional distribution information of a double-sweet-spot index of a target reservoir, and obtaining a fracturing crack propagation simulation result corresponding to the to-be-analyzed regions; based on an established three-dimensional geologic model of a target reservoir, according to distribution information of a water-bearing stratum and distribution information of a thin interlayer in the three-dimensional geologic model of the target reservoir, according to a fracturing fracture extension simulation result corresponding to a to-be-analyzed area, after it is determined that fracturing fractures in the to-be-analyzed area do not communicate with the water-bearing stratum and can penetrate through the thin interlayer, the fracturing fractures in the to-be-analyzed area are determined to be communicated with the water-bearing stratum. Marking the to-be-analyzed area as a double-dessert area; and traversing the plurality of to-be-analyzed areas of the target reservoir to obtain all double-sweet-spot areas so as to complete double-sweet-spot prediction of the target reservoir. According to the method, the distribution information of the complicated geological structures of the aquifer and the thin interlayer and the crack propagation characteristics are considered at the same time, so that the prediction precision of the double-dessert area is improved, and the economy of reservoir development is improved.

The invention provides a shale oil reservoir fracturing process monitoring method, device and system, and belongs to the field of shale oil development. The method comprises the steps that original stratum physical property parameters and stress parameters of a target reservoir are obtained, and an initial reservoir model is constructed through numerical simulation; performing CT scanning and core pore three-dimensional reconstruction on the core obtained by the first coring to obtain an initial core pore network model; applying the monitored fracturing construction process to the initial reservoir model to obtain a dynamic construction reservoir model; after fracturing construction is finished, CT scanning and three-dimensional reconstruction of core pores are carried out on the core obtained through second-time coring, and a fractured core pore network model is obtained; through the model, the process of fracturing transformation on the target reservoir is visually displayed. And the shale reservoir fracturing crack propagation characteristic rule is obtained on the spatial scale, the influence of the production process on the fracturing crack is monitored for a long time on the time scale, and the production dynamic rule is predicted more accurately.

The invention relates to the technical field of well site fracturing, and discloses an intelligent fracturing method and system for precise fracture forming, and the method comprises the steps: collecting underground multi-dimensional monitoring data in real time; dynamically constructing and correcting a three-dimensional crack expansion model by using the monitoring data, and outputting a prediction path containing crack geometric parameters; based on the prediction path and the real-time downhole pressure deviation, a control instruction is generated through an optimization algorithm; and the control instruction is executed, the sliding sleeve valve element is driven to move, the flow of fracturing fluid is adjusted, and accurate formation of cracks is controlled. According to the method, by fusing underground multi-dimensional monitoring data and dynamically correcting the three-dimensional crack propagation model, prediction deviation caused by single data dimension and static model solidification in a traditional method is overcome, prediction errors of the crack length and the steering angle are reduced, accurate prediction and control of the crack propagation path are achieved, and the method is suitable for large-scale popularization and application. And the geological targeting property of fracturing construction is obviously improved.

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 bed gas crossing fracturing demonstration and optimization method, which comprises the following steps: acquiring an underground rock core, carrying out mechanical and physical property parameter tests on a coal bed and an interlayer, and constructing a longitudinal multi-thin interbed geologic model based on a full-three-dimensional structured grid, including mechanical characteristics and stress characteristics of each thin layer; the positions of perforation points are changed, a segmented clustering scheme is completed, and the longitudinal layer penetrating effect of cracks is simulated; the fracturing construction parameters are optimized with the longitudinal crossing effect as a target, and the fracturing construction parameters comprise the displacement, the sand adding amount, the number of single-cluster holes, the gap distance and the number of intra-segment clusters; simulating the overall fracture form and fracture parameters through a full-three-dimensional fracture propagation simulation platform; micro-seismic testing is carried out to monitor the fracture crossing effect, and the effectiveness of fracture crossing fracturing construction parameters is demonstrated. According to the embodiment of the invention, aiming at a thin interbed type coal bed gas reservoir, horizontal well crack longitudinal crossing fracturing construction parameters are optimized, the coal bed gas yield is improved, and higher economic benefits are obtained.

The invention relates to a true triaxial fracturing test magnetofluid monitoring system and method, and belongs to the field of coal bed gas exploration and development. The system comprises a magnetic fluid mixing device, an injection device, a 4 * 4 magnetic induction sensor array, a data acquisition device, a high-pressure water pump device and a true triaxial experiment device. The method comprises the following steps: mixing magnetic fluid and adjusting viscosity; injecting a test piece; applying three-dimensional stress; monitoring magnetic field change in real time; millimeter-level positioning and three-dimensional visualization of crack expansion are achieved through magnetofluid dynamic response and data collected by a magnetic induction sensor array in combination with differential analysis, edge detection and a finite element inversion algorithm, and the magnetofluid recovery rate is larger than 95%. The method solves the problems that traditional monitoring is low in precision and poor in real-time performance, and is suitable for dynamic analysis of coal bed gas and shale gas fracturing cracks.

The invention belongs to the technical field of petroleum development fracturing, and relates to a thin interbed shale oil seam height crossing evaluation method and system, and the method comprises the steps: S1, constructing a longitudinal continuous multi-small-layer geomechanical model at different dessert positions; s2, on the basis of a geomechanical model, different thin interbed characteristic fracturing physical simulation experiments are constructed; s3, based on a geomechanical model, constructing different thin interbed characteristic crack propagation numerical simulation experiments; and S4, combining a physical simulation experiment with a numerical simulation experiment, and constructing a thin interbed shale oil seam high crossing evaluation chart according to the stress difference of different reservoir interlayers and the thickness of the interlayers. The system comprises a first construction module, a second construction module, a third construction module and a fourth construction module. According to the method, the artificial fracture propagation rule under different lithologic sequence, mechanical parameters and interlayer interface characteristics is determined, and the local fracture height evaluation chart is established, so that the optimization of the fracturing scheme is guided in a targeted manner, and the integral reconstruction effect of the dessert is improved.

The embodiment of the invention provides a fracturing staged clustering method and device for a horizontal well. The method comprises the steps that well periphery natural fracture distribution data and well logging interpretation data of a target horizontal well are obtained; according to the well periphery natural fracture distribution data and the well logging interpretation data, performing preliminary segmentation on a well periphery reservoir of the target horizontal well to obtain different types of reservoirs; horizontal well clustering fracturing crack propagation models are constructed for the different types of reservoirs respectively; performing fracture propagation simulation according to the horizontal well clustering fracturing fracture propagation model to obtain a fracturing fracture form; determining single-section perforation cluster parameters of different types of reservoirs according to the fracturing fracture form; and according to the single-section perforation cluster parameters and the well logging interpretation data, the specific section position and the perforation cluster position of the target horizontal well are determined. According to the method, the unconventional oil and gas reservoir fracturing transformation effect can be improved.

The invention relates to the technical field of hydraulic fracturing numerical simulation, aims at solving the problem that in the prior art, shale reservoir multi-scale natural fractures are difficult to simulate, and provides a shale reservoir multi-scale fracture numerical simulation method, a computer device, a readable storage medium and a program product. The method comprises the following steps: S1, preparing a standard shale core; s2, acquiring natural fracture distribution information of the standard shale core; s3, generating a natural fracture unit based on the obtained natural fracture distribution information; s4, generating a rock matrix unit; s5, embedding a global cohesion unit; based on the distribution information of the multi-scale natural fractures, random expansion numerical simulation of the multi-scale fractures of the shale reservoir is achieved through the cohesion unit, the technical problem that the multi-scale natural fractures of the shale reservoir are difficult to simulate is solved, the multi-scale natural fractures in the shale reservoir can be effectively activated, and the expansion form of the hydraulic fracture can be accurately predicted; the method can be used for supporting hydraulic fracturing reservoir transformation and fracturing construction optimization and adjustment.

The invention discloses a hot dry rock hydraulic fracture numerical simulation method based on a continuous-discontinuous unit method, and the method comprises the steps: firstly building a solid stress field calculation model, a fluid field calculation model and a temperature field calculation model, and determining that the fracture criterion of hot dry rock meets the maximum tensile stress criterion and the Mohr-Coulomb criterion; then, according to the actual condition of the hot dry rock, a hydraulic fracturing model of the natural fracture development hot dry rock geothermal reservoir is established; and finally, combining the established fracturing model with the calculation models to carry out iterative solution, judging whether the hydraulic fracturing model generates a new crack or not by utilizing fracture accurate measurement in the solution calculation process, and carrying out model crack updating until the hot dry rock crack propagation numerical simulation process is completed. According to the method, on the premise of considering the influence conditions of thermal stress and natural fractures, numerical simulation is conducted on deep hot dry rock hydraulic fracture extension, the simulation precision is high through test verification, and therefore data support is provided for follow-up hot dry rock geothermal reservoir fracturing construction parameter optimization.

The invention discloses an experimental device and method for positioning and artificially manufacturing fractures in a borehole and expanding the fractures. The experimental device comprises a tubular column carrier unit, and a positioning anchoring system, a mechanical fracture forming pretreatment system, a thermal shock fracturing system and a control terminal which are integrated on the tubular column carrier unit. The positioning anchoring system is used for detecting the well wall and locking the target depth and direction; the mechanical crack-making pretreatment system is used for cutting at the locking position to form an initial physical gap; the thermal shock fracturing system presets a thermal stress field through a heating assembly, and utilizes a cold shock assembly to spray low-temperature fluid to generate transient temperature difference stress to induce cracks to crack from notches and expand. And the control terminal controls the action time sequence of each system. According to the method, through the mode of mechanical drilling and thermal coupling, fixed-point and directional accurate fracture forming in a borehole is achieved, the generated fracture shape is close to that of a natural fracture, and the problems that a traditional method is inaccurate in positioning, uncontrollable in shape and large in damage to the whole sample are solved.

The invention provides a stratified reservoir fracturing crack propagation simulation method, which comprises the following steps of: firstly, performing discrete processing on a model corresponding to a stratified reservoir according to a preset polyhedral block to obtain at least one discrete matrix unit, and secondly, determining at least one attribute model corresponding to the at least one discrete matrix unit, according to the at least one attribute model, fluid-solid coupling solution is carried out on the at least one discrete matrix unit, fracture information between adjacent discrete matrix units, fluid pressure distribution between the adjacent discrete matrix units and stress states of the adjacent discrete matrix units are determined, and then the strata characterization parameters of the reservoir stratum are combined to determine the strata characterization parameters of the reservoir stratum. And crack fracture information of stratified reservoir fracturing is determined. According to the technical scheme, on the basis of the stratified reservoir fracturing fracture form and the influence mechanism thereof, the fracture information of stratified reservoir fracturing is determined, and a basis is provided for improving stratified reservoir transformation benefits.