96 results about "Fracture process" patented technology

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 provides a hydraulic fracturing fracture net distribution form near-field monitoring method, which comprises the following steps of: arranging a plurality of roof monitoring holes in roadways on two sides of an underground coal mine working surface, installing electromagnetic signal sensors in each roof monitoring hole and on anchor rods of roadway stoping sides, and constructing a full-space monitoring network covering a hydraulic fracturing layer; a data interpretation processing module of the electromagnetic signal time-shifting imaging analysis system comprises a multi-field coupling mathematical model for analyzing and deducing real-time imaging of electromagnetic signals; in the hydraulic fracturing process, an electromagnetic signal sensor is used for monitoring a current field, an electromagnetic field and an ion diffusion field in the rock mass fracture development and expansion process, a monitoring result is substituted into an electromagnetic signal time-shifting imaging analysis system for calculation and feature value extraction, and the fracture net distribution form is deduced through the feature value. According to the invention, the expansion path of the fracturing fluid in the rock stratum can be monitored in real time, the three-dimensional distribution form of the hydraulic fracturing fracture network can be inverted, and a new technical support is provided for the inspection of the hydraulic fracturing pressure relief effect of the underground coal mine.

A method for controlling a fracture height in unconventional oil and gas reservoirs under multi-bedding interference is provided. The method includes: obtaining geological parameters of a target horizontal well, and determining a fracturing fluid and construction parameters based on a production capacity target of the target horizontal well; determining a hydraulic fracturing process of the target horizontal well based on a hydraulic fracturing model for processing the multi-bedding interference, and evaluating the fracture height; comparing the fracture height with an expected control height, if the fracture height is greater than the expected control height, reducing a displacement of the fracturing fluid or a total time of a hydraulic fracturing to update the construction parameters until the fracture height is less than the expected control height; and performing the hydraulic fracturing on the target horizontal well based on updated construction parameters.

The invention relates to the field of electric power installation equipment, in particular to an electric power line phase-to-phase spacer fracture early warning induction device, and solves the problems of low efficiency, time delay and occupation of extra manpower of a traditional inspection means in the prior art. A signal is sent out through the inevitably accompanying physical deformation of a strain sensing optical fiber in the fracture process of the spacer to carry out judgment and early warning, real-time monitoring is achieved, and the labor cost is reduced. The spacer comprises a core rod, wire clamps are arranged at the left end and the right end of the core rod, and a hollow cavity is formed in the core rod in the axis direction; a hollow cavity is formed in the core rod, a spirally distributed strain sensing optical fiber is arranged in the hollow cavity, the strain sensing optical fiber is used for sensing the stress change of the core rod, and one end of the strain sensing optical fiber extends out of the hollow cavity and is connected with a fiber bragg grating demodulator.

The invention discloses a method for predicting the service behavior of an oil and gas pipeline under a stress corrosion cracking condition, and belongs to the field of material performance analysis and prediction. Firstly, based on a convection diffusion equation, a real stress intensity factor of an oil and gas pipeline crack tip is used as an unknown quantity to obtain a stress distribution condition; then, applying boundary conditions and a crack propagation criterion in fracture mechanics, and performing preliminary calculation to obtain crack propagation behavior characteristics of the one-dimensional semi-analytical model; and finally, calibrating and calculating the diffusion coefficient of the material parameter in the one-dimensional semi-analytical model to obtain real full-life service time information of the oil and gas pipeline material. According to the method, the full-life behavior information of stress corrosion cracking can be quickly obtained, and a partial differential equation does not need to be solved; on the basis of fracture mechanics, the mechanism of repeated fracture and reconstruction of the passivation layer in the fracture process can be reproduced; the full-life service time of the oil and gas pipeline can be effectively predicted, and the parameter calibration method can be applied to other conditions and is wide in application range.

The invention discloses a fracturing fluid viscosity dynamic regulation and control device and method for a true triaxial hydraulic fracturing experiment, and the method comprises the following steps: (1) starting and detecting whether a true triaxial hydraulic fracturing experiment system operates normally, verifying the accuracy and rationality of a Smith time delay compensation algorithm and adaptive PID control, and applying in-situ stress to a fracturing sample; (2) setting an initial viscosity value, injecting fracturing fluid into the fracturing sample at a constant flow, and synchronously starting an acoustic emission and resistivity signal receiver; (3) the fracturing effect is evaluated according to implementation feedback information such as acoustic emission / resistivity signals and fracturing pressure in the fracturing process, and the fluid mixing proportion is updated to track a new viscosity set value containing time delay compensation; (4) repeating the step (3) until a relatively complex hydraulic fracture structure is formed or the fracture thoroughly penetrates through the fracturing sample; and (5) based on different viscosity change paths set in the step (3), quantitatively analyzing the inhibition or promotion effect of viscosity change on fracture expansion, turning and branches, and realizing the maximization of the fracture network volume of hydraulic fracturing. A double-cylinder injection system capable of adjusting the fluid mixing proportion in real time is introduced, the limitation of traditional static mixing of the fracturing fluid is broken through in combination with a Smith time delay compensation algorithm and self-adaptive PID control, and the complex influence mechanism of dynamic viscosity change of the fracturing fluid on crack propagation and propping agent migration is explored; and the simulation capability and the research depth of the experiment are improved.

The invention provides a dynamic load-oriented brazed diamond bonding strength testing device and method. The dynamic load-oriented brazed diamond bonding strength testing device comprises a base, a test framework, a self-adaptive sample holding unit, a data acquisition unit and a visual auxiliary alignment unit, the self-adaptive sample holding unit realizes stable clamping and angle adjustment of a sample through a rotatable platform, a translation bottom table, a hydraulic clamping cylinder and an angle adjusting piece; the data acquisition unit acquires a shear force-displacement curve by using a fiber bragg grating sensor, and a high-speed camera records a fracture process; and the vision-assisted alignment unit (high-resolution industrial camera) is used for calibrating the positions of the sample and the pressure head. The method comprises the steps of intelligent pre-characterization clamping, variable load dynamic shear testing, in-situ fracture mode judgment, multi-mode effective fracture area measurement and multi-dimensional strength characterization. According to the invention, the sample positioning and clamping stability is improved, the loading interference is reduced, the interface bonding strength is quantitatively and reliably represented under the dynamic load, and the test accuracy and repeatability are guaranteed.

The invention discloses a sleeve deformation simulation experiment system in a deep coal bed gas fracturing process. The sleeve deformation simulation experiment system comprises a test sleeve, a strong-plasticity deep coal rock sample, a sleeve deformation visual monitoring module, a target horizon deformation and crack propagation monitoring module, a fracturing fracture network global monitoring module, a liquid injection module and a ground stress loading module. The sleeve deformation visual monitoring module is used for monitoring the deformation damage condition of the test sleeve; the target horizon deformation and crack propagation monitoring module is used for monitoring surface deformation and crack propagation conditions of the sample; and the fracture network global monitoring module is used for monitoring the fracture expansion scale. According to the system, multi-load application of casing deformation can be achieved, the strong plasticity characteristic of deep coal bed gas is simulated, the fracture expansion scale and the casing deformation amount in the hydraulic fracturing process are accurately monitored, and risk level prediction of the influence of the hydraulic fracture expansion rule on casing deformation is achieved. The invention further discloses a sleeve deformation simulation experiment method in the deep coal bed gas fracturing process.

The invention relates to the technical field of rock mass mechanical analysis, and discloses a shale bedding mechanical property inversion method, equipment and a medium. The method comprises the following steps: acquiring a mechanical signal and a generated electric signal when a target shale is fractured under external applied force; dividing the shale fracture process into a plurality of time intervals according to a plurality of characteristic events in the electric signals and a bedding geometric model of the shale, and enabling each time interval to correspond to an expansion stage of a shale crack in one bedding interval; according to the equivalent path length of the crack in each bedding interval and the time difference between the adjacent characteristic events, determining the expansion speed of the crack in each bedding interval; according to the mechanical signals and a bedding geometric model, determining the stress intensity of each bedding interval of the shale in the fracture process; according to the stress intensity and the expansion speed, the equivalent fracture energy and fracture toughness of each bedding section of the shale in the fracture process are determined through the energy balance relation of the bedding sections in the fracture process, and therefore the shale bedding mechanical properties are inverted.

The application discloses a kind of coal rock nonlinear fracture propagation length quantitative determination method based on multiple parameters, comprising: preparation of coal rock sample containing notch;Spray black and white speckle on the surface of sample, install acoustic emission sensor, clip type extensometer and displacement sensor;Carry out three-point bending peak after cycle loading and unloading fracture experiment, record load, crack opening, force point displacement, acoustic emission waveform and DIC image;Through COD-P and LPD-P curve calculation mechanics flexibility, back calculation to solve stress constraint crack length;From acoustic emission positioning, obtain the spatial distribution histogram of breakage dissipation energy, combined with DIC horizontal displacement gradient threshold cloud picture, determine equivalent crack tip and length;Further calculate coal rock fracture process zone length, and intuitively show nonlinear fracture propagation path.The application provides a kind of crack dynamic change quantitative determination method based on mechanics flexibility-displacement gradient-energy dissipation distribution multiple physical parameters, reduce the influence of human subjective consciousness, and the measurement result is accurate and reliable.

The invention relates to two-way integrated hydraulic fracturing equipment and a using method, and belongs to the technical field of coal mine roof cutting. The system comprises a first drill rod, a second drill rod, sealing devices and a kerf fracturing device, the first drill rod and the second drill rod are hollow rods, one end of the first drill rod and one end of the second drill rod are connected through the kerf fracturing device, and the sealing devices are arranged at the other end of the first drill rod and the other end of the second drill rod respectively; the sealing devices adopt hole packers, the two hole packers are connected through a sealing pipeline, and the sealing pipeline sequentially penetrates through the first drill rod, the kerf fracturing device and the second drill rod. The problems that in the prior art, drill hole joint cutting is discontinuous, joint cutting and fracturing procedures are separated, and a hole sealing area is inaccurate are solved, the overall hydraulic fracturing effect of drill holes is improved, the failure rate in the equipment operation process is reduced, and the effects of sequential joint cutting and segmented fracturing in the drill holes are achieved.

The invention discloses an abrasive water jet rock breaking simulation method based on a DEM-CFD coupling method. Establishing an EBPM bonded rock mass discrete element model through a discrete element DEM, and calibrating mesoscopic parameters through a virtual mechanical test; simulating a water-abrasive two-phase flow through fluid dynamics CFD, and adopting a Gidaspow drag force model; the DEM-CFD bidirectional interface realizes real-time coupling; carrying out post-treatment to extract an erosion morphology and a crack network; the method can effectively simulate the rock mass fracture process and the large deformation behavior in the water jet rock breaking process and reveal rock mass damage evolution from the microscopic scale, and can be widely applied to research of water jet assisted rock breaking in the fields of civil engineering, mining, petroleum energy, marine resources and the like.

The invention provides a natural fracture acid fracturing process parameter optimization method and device, equipment and a medium, and the optimization method comprises the steps: obtaining geological and engineering data of a target block, carrying out the fitting of the geological and engineering data to obtain a natural fracture fitting model, determining the natural fracture fitting parameters according to the natural fracture fitting model, and carrying out the acid fracturing process parameter optimization of the target block. Further establishing a pressure drop characteristic parameter model and a natural fracture characteristic parameter model by using actually measured pressure data, and further establishing a productivity prediction model; and according to the productivity prediction model and the natural fracture fitting model, optimizing the acid fracturing process parameters of the natural fractures. According to the method, the condition of natural fractures encountered by underground hydraulic fractures is innovatively and dynamically judged according to the wellhead pressure change rule in the multi-stage alternate acid fracturing process, parameters can be dynamically adjusted on this basis to achieve dynamic optimization of a pump injection program, and a basis is provided for whether the natural fractures are transformed or not in real time in the construction process; and a new thought and a new method are provided for acid fracturing parameter design and optimization.

The application provides a compact dolomite reservoir composite acid fracturing process parameter evaluation system and method, which comprises a simulated fracture device, an acid injection device and a circulating water injection device. The acid injection device comprises an acid storage container, an acid injection pipeline and an acid discharge pipeline. The acid injection pipeline is connected to the acid storage container and the acid injection liquid inlet hole of the simulated fracture device at both ends. The acid discharge pipeline is connected to the acid injection liquid outlet hole of the simulated fracture device. The circulating water injection device comprises a water storage container, a water inlet pipeline and a circulating water discharge pipeline. The water inlet pipeline is connected to the water storage container and the water injection liquid inlet hole of the simulated fracture device at both ends. The circulating water discharge pipeline is connected to the water injection liquid outlet hole of the simulated fracture device and the water storage container at both ends. The application adopts reverse thinking to evaluate the composite acid fracturing process parameters such as the preflush / acid viscosity ratio, the pump injection displacement and the alternating series by taking the fractal dimension, the acid volume, the flow conductivity and the acid fluid loss as the targets, and is more specific and systematic.

The invention provides a multiphase dielectric material microstructure three-dimensional fracture whole process simulation method based on space-time sequence prediction. The method comprises the following steps: S1, acquiring sample data; s2, constructing and training a deep learning model network; and S3, model verification: inputting historical surface crack information of the composite material into the trained generative network to obtain a subsequent fracture damage process of the composite material, applying Wasserstein distance quantification, comparing forms between fracture surfaces, and judging whether the performance of the model is good or bad. According to the method, the fracture surface in the entity can be predicted according to the historical apparent cracks of the composite material under the condition that component distribution information of the composite material is not needed; a network model is trained completely from the perspective of observation data, and it can be theoretically achieved that a prediction result is almost consistent with a result observed in an experiment; the calculation efficiency is high, and the calculation duration can be shortened from weeks to seconds; pixel-level modeling can be realized; the fracture process in the material can be predicted according to the apparent cracks of the material.

This invention belongs to the field of fracture characterization and reservoir hydraulic fracturing simulation technology. It discloses a method and related equipment for characterizing natural fractures and simulating reservoir damage evolution using a phase-field model. By distinguishing primary and secondary natural fractures based on a discrete fracture network and constructing a model, it achieves accurate characterization of the different sizes and spatial heterogeneity of primary / secondary natural fractures in the model. Natural fractures are characterized as mechanically weak surfaces with differentiated parameters. Hydraulic fractures can capture and interact with natural fractures. Combining a phase-field damage model and a rock mechanics constitutive model, it can accurately simulate key behaviors such as activation and deflection during natural fracture propagation without pre-setting fracture paths, avoiding numerical instability and low computational efficiency. Through dynamic coupling analysis of the entire fluid-solid-damage process, it takes into account the influence of multiple factors such as geostress and fluid pressure, improving the accuracy of phase-field simulation, reducing simulation distortion, providing reliable support for fracturing design optimization, helping to improve reservoir stimulation effects and production benefits, and ensuring the smooth implementation of fracturing processes.

This invention relates to the field of connecting rod processing technology, specifically to a fracture device and method for connecting rods in large machinery. The device includes a laser marking machine worktable, a fracture device worktable, and a connecting rod. A laser marking machine and a laser marking feeder are mounted on the upper end of the laser marking machine worktable. A fracture device is mounted on the upper end of the fracture device worktable. The laser marking feeder and the fracture device are used for positioning the connecting rod. The laser marking feeder includes a small-end positioning pin and a large-end positioning pin. The small-end positioning pin is used for positioning the small end of the connecting rod, and the large-end positioning pin is used for positioning the large end of the connecting rod. The fracture device includes a small-end positioning component and a fracture block. The small-end positioning component is used for positioning the small end of the connecting rod, and the fracture block is used for limiting the fracture of the large end of the connecting rod. Compared to existing sawing processes for connecting rods in large machinery, the laser marking fracture process of this invention simplifies the processing flow and improves the performance of the connecting rod.

The application provides a kind of transmission wire ice ridge radial fracture strength testing device and method, it is related to transmission line icing test technical field.The application is through integration ice ridge growth module, ice ridge clamping mechanism and thrust exertion and detection system, constitutes a closed technical scheme for ice ridge test.The application first drops water to transmission wire under low temperature environment, to simulate the natural growth forming process of ice ridge, so that the test is closer to real working condition;Ice ridge clamping mechanism clamps ice ridge by jaw assembly;Thrust exertion and detection system exerts controllable thrust to jaw assembly and records the thrust value of ice ridge in real time, ensures the accurate collection of thrust data, realizes the quantitative evaluation of mechanical properties in the fracture process of ice ridge.

The invention discloses an intelligent fracturing system and method. The system comprises a carrying platform, a navigation device I, a fracturing device, a sensing device, an intelligent control system, a navigation device II, a moving device, a working arm and a pipeline switch controller. The method comprises the following steps: 1) arranging a drill hole in a top plate of a to-be-worked area, and placing a fracturing system; (2) a path is autonomously planned through an intelligent control system and a navigation device II, and a moving device is controlled to move to the position near the area to be fractured; (3) the intelligent control system controls the working arm to move to a to-be-fractured area, fracturing is conducted through a fracturing device, and cracks are generated; (4) real-time data in the fracturing process are monitored through a sensing device, and after the fracture state is stable, the intelligent control system controls the working arm to retract back to the carrying platform; and 5) returning to the step 2) until all fracturing operations in the to-be-worked area are completed. The fracturing precision and the resource utilization rate are remarkably improved, and an intrinsically safe, green and efficient intelligent solution is provided for safe and efficient mining of deep coal.

The invention discloses a hydrogen-induced cracking molecular dynamics-cohesion cross-scale simulation method which comprises the following steps: constructing a geometric model reflecting an actual material microstructure on the basis of multi-scale structure characteristics such as grain size, grain boundary angle and the like obtained by metallographic observation and electron back scattering diffraction test; simulating a fracture process of a microscopic interface under different hydrogen concentrations through a molecular dynamics method, obtaining traction-separation data, and calibrating core parameters of the cohesion model; embedding the parameters into a polycrystalline finite element model constructed based on a Thiessen polygon to realize parameter transmission and coupling calculation from a micro scale to a micro scale; the cohesion unit accurately describes hydrogen-induced grain boundary damage and crack propagation behaviors. According to the method, through multi-scale correlation modeling and direct parameter calibration, the reliability and prediction precision of the model are remarkably improved, and a theoretical basis and an engineering applicable tool are provided for hydrogen embrittlement resistance design and service life evaluation of a hydrogen equipment material.

An improved system for well boring and related hydraulic fracturing processes, which typically includes a sleeve that may be formed with some composite material to provide a stable and consistent low-friction surface, which surface may potentially improve the seating and uniform breaking of slip segments in a fracking plug application. The system may be formed, in part, by a filament winding process.

This invention belongs to the field of gas extraction technology, and particularly relates to a method for efficient gas extraction through long-distance mining-induced pressure relief and pre-fracturing collaboration. This invention divides and calculates the "three zones" formed by mining-induced pressure relief, identifies the collaboration between mining-induced pressure relief and pre-fracturing in conjunction with the hydraulic fracturing fracture propagation law, optimizes the design of horizontal well locations and depths, determines the fracturing process and optimizes perforation fracturing parameters, and uses microseismic fracture monitoring and evaluation technology for real-time monitoring of hydraulic fracturing during the fracturing process. By combining the "three zones" generated by mining-induced pressure relief with segmented horizontal well fracturing, regional pressure relief is achieved, resulting in the effect of "extracting multiple layers from one layer."

The application discloses a hydrogen-induced cracking molecular dynamics-cohesion cross-scale simulation method, comprising the following steps: constructing a geometric model reflecting the actual microstructure of a material based on the multi-scale structure characteristics such as grain size and grain boundary angle obtained through metallographic observation and electron backscatter diffraction experiments; simulating the fracture process of a micro-interface under different hydrogen concentrations through a molecular dynamics method, obtaining traction-separation data, and calibrating the core parameters of a cohesion model; embedding the above parameters into a polycrystalline finite element model constructed based on a tessellation polygon, realizing parameter transmission and coupled calculation from a micro-scale to a meso-scale; and accurately describing hydrogen-induced grain boundary damage and crack propagation behavior through a cohesion element. The method significantly improves the reliability and prediction accuracy of the model through multi-scale correlation modeling and direct parameter calibration, and provides a theoretical basis and an engineering applicable tool for hydrogen-induced cracking resistance design and life assessment of equipment materials.

The application discloses a method and device for simulating the influence of fracturing construction on ground stress, which comprises the following steps: obtaining the design parameters and perforation parameters of a fracturing well; establishing a hydraulic pressure joint expansion model according to the design parameters of the fracturing well; establishing a numerical model of the influence of fracturing construction on a stratum according to the hydraulic pressure joint expansion model and the perforation parameters; and determining the ground stress variation law of the stratum around the fracturing well according to the numerical model of the influence of fracturing construction on the stratum. The method has the beneficial effects that the hydraulic pressure joint expansion model is established according to the design parameters of the fracturing well, the numerical model of the influence of fracturing construction on the stratum is established in combination with the perforation parameters, the ground stress variation law of the stratum around the fracturing well is determined according to the numerical model of the influence of fracturing construction on the stratum, and thus the ground stress variation law of the stratum around the fracturing well in the fracturing process can be obtained, which provides technical support for revealing the mechanism of the drilling interference caused by fracturing, and enriching and perfecting the related theory.

The invention provides a solid fracture calculation method and device based on smoothed particle dynamics. The method comprises the following steps: establishing a smoothed particle dynamics calculation model, setting conditions, and obtaining a stress state between particles; and when the stress state between any particle pair meets the judgment basis, judging that the particle pair is broken and breaking the link bond. And calculating the midpoint position of the fracture particle pair and setting the midpoint position as a base point, and establishing a failure surface by taking the connecting line direction of the two fracture particles as a normal direction. And on the basis of a preset smooth kernel function, in the fracture particle influence domain, according to the position relationship between the particles and the fracture surfaces, dividing the particles in the domain into a fracture surface same-side set and a fracture surface different-side set, keeping same-side links, and disconnecting different-side links. And repeating the steps until the calculation of the fracture process of the solid structure is completed. According to the method, stable construction of the failure surface is realized, the influence of real-time position disturbance is avoided, and the simulation precision and the applicability of the algorithm are improved by controlling the link keys in the complete influence domain in a regional manner.

The application provides a water injection well pressure analysis method considering the influence of fracture induced by pressure drive water injection, which comprises the following steps: step 1, establishing a water injection well pressure analysis model considering the influence of fracture induced by pressure drive water injection; step 2, solving the water injection well pressure analysis model considering the influence of fracture induced by pressure drive water injection; step 3, obtaining a water injection well double logarithmic pressure analysis curve through analysis, and judging different flow stages of the reservoir in the fracturing process according to the curve; and step 4, analyzing the bottom hole pressure response characteristics of the pressure drive water injection well, and applying the characteristics to an actual well to verify the accuracy of the established model. The water injection well pressure analysis method considering the influence of fracture induced by pressure drive water injection establishes a water injection well pressure analysis model considering the dynamic expansion of the fracture, has certain technical difficulty, and can determine the flow stage of fluid in the reservoir at different production moments.

In a metal plate molding limit determination method according to the present invention: a surface of a test piece 101 is molded while being sequentially images, and a strain on the surface of the test piece 101, which is generated from the start of molding to a point at which fracture occurs, as well as three-dimensional coordinates of the surface of the test piece 101, are measured to construct a database (S10); an evaluation point string is set along a fracture orthogonal direction that is orthogonal to a fractured section 103 generated in the test piece 101, and strain or three-dimensional coordinates in the evaluation point string are extracted from the database (S20); and a fracture orthogonal direction gradient of the strain or the three-dimensional coordinates in the evaluation point string is calculated, and a molding limit is determined (S30).

The application discloses a test method for studying the connection mechanism of hydraulic fractures and high-angle shear type fractures, and belongs to the technical field of indoor test of rock mass hydraulic fracturing. The test method for studying the connection mechanism of hydraulic fractures and high-angle shear type fractures preforms a through fracture at the side of a sample close to the top, performs high-temperature thermal shock treatment on the inner side of the through fracture, thereby forming a gradient damage zone, and processes a perforation upward in the middle of the bottom surface of the sample; the treated sample is placed in an experimental device, and a plurality of acoustic emission probes are pasted on the surface of the sample; a surrounding pressure and an axial pressure are sequentially applied by using a staged loading mode, then high-pressure water fracturing is continuously carried out in the perforation at a constant rate, and the fracture pressure and the corresponding flow rate are recorded when the sample is broken; the hydraulic fracturing process is analyzed according to the flow-pressure curve obtained by the test and the information collected by the acoustic emission probes, and the connection law of the hydraulic fracturing fractures and the through fractures is obtained by combining the CT three-dimensional reconstruction technology after the test.

The application discloses a fracturing method for improving sanding strength of high-stress shale reservoirs. The steps are: collecting reservoir parameters, simulating and optimizing fracturing process parameters; setting the upper limit pressure value of the fracturing unit in steps; pretreating the reservoir by injecting acid liquid with large displacement; creating a fracture by injecting preflush slickwater; injecting slickwater carrying small-diameter ultra-low-density proppant; switching to small-diameter conventional-density proppant; repeating the two rounds of sand switching to probe the optimal sand-liquid ratio at different stages; switching to mixed sanding of different-density proppant carrying small and medium-diameter combined proppant; switching to medium-diameter ultra-low-density proppant for sealing; performing fracturing fluid displacement operation to complete single-stage construction; and repeating the above steps. The method has the advantages of improving the fracturing reconstruction effect of high-stress reservoirs, avoiding the economic loss caused by long operation time and easy damage of the fracturing unit under long-time high-pressure pumping due to low sanding efficiency, greatly improving the sanding efficiency, reducing the material cost and construction cost, and achieving the purpose of cost reduction and benefit increase.

The application discloses a kind of (C 20 H 20 P)2MnBr4 In material stress visualization and fracture prediction application, belongs to stress visualization and fracture prediction technical field.It includes the following steps: (1) preparation sensing workpiece: liquid (C 20 H 20 P)2MnBr4 Plastic into the three-dimensional entity consistent with target workpiece geometry;(2) load and collect light signal: under the condition of preset load, load is applied to the sensing workpiece, and the dynamic light image sequence generated under the action of load is synchronously collected;(3) analysis light signal and mapping mechanics behavior.The application realizes the direct physical visualization of stress and fracture process: the application is converted into intuitive, global, real-time optical image by (C 20 H 20 P)2MnBr4 Emission characteristics, abstract simulation calculation cloud picture and discrete measurement data.Stress concentration, crack initiation and expansion and other key mechanical behavior "at a glance", greatly reduce the analysis threshold and interpretation difficulty.