Deep heat storage large-scale fracturing construction scheme design method based on weak structure

Abstract

The invention discloses a deep heat storage large-scale fracturing construction scheme design method based on a weak structure, and relates to the technical field of high-temperature geothermal resource exploration and development, and the method comprises the following steps: depicting and characterizing the weak structure of a deep heat storage large-scale fracturing stratum to obtain a comprehensive characterization large model; based on the comprehensive characterization large model, delineation and fracturing performance evaluation are conducted on a weak structural zone of the deep heat storage scale fractured stratum, and a delineated area is obtained; on the basis of the delineated area, the farthest disturbance range and distance of fracturing transformation of the weak structure of the deep heat storage scale fractured stratum are predicted; and determining a well spacing, designing a well location, deploying a well pattern and optimizing a fracturing layer section based on the fracturing property and the predicted farthest disturbance range and distance of thermal storage fracturing transformation, and completing the design of a deep thermal storage large-scale fracturing construction scheme. According to the method, through construction and analysis of the comprehensive characterization large model, the stratum weak structural zone suitable for fracturing can be accurately delineated, the farthest disturbance range and distance of fracturing transformation are predicted, and efficient mining is achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of high-temperature geothermal resource exploration and development, and in particular relates to a design method for a large-scale fracturing construction scheme for deep heat reservoirs based on weak structures. Background Art

[0002] As an important geothermal reservoir, deep heat storage refers to high-temperature rock with a temperature greater than 150℃ and a burial depth greater than 3500m. The exploration and development of deep geothermal resources in my country and the research and development of related core technologies are still in the primary exploration stage. So far, no commercial exploitation has been successfully achieved, and no systematic exploration and development technology methods suitable for my country's geothermal geological conditions have been formed. Although deep geothermal resources have the advantages of large reserves, renewable, and green environmental protection, compared with traditional fossil energy such as oil and natural gas, they are still low-value energy in terms of output. This means that to obtain the same value of thermal energy resources, a larger volume of high-temperature liquid needs to be extracted from the formation, which has higher development costs and technical investment. In other words, under the current conditions, the only way to exploit deep heat storage is to break through the large-scale reservoir fracturing transformation and obtain an ideal larger volume of fracture network structure in order to successfully realize the commercial exploitation of EGS. However, relevant research has not yet made a breakthrough, which has always been the biggest technical problem restricting the large-scale development and utilization of deep geothermal resources in my country. Summary of the invention

[0003] The present invention proposes a design method for a large-scale fracturing construction plan for deep thermal reservoirs based on weak structures, aiming to study the action mechanism of weak structures in large-scale fracturing of deep thermal reservoirs, optimize the weak structure zones of the formation where large-scale fracturing can be implemented, and achieve good results through low-displacement and low-intensity fracturing.

[0004] To achieve the above object, the present invention provides the following solutions:

[0005] A method for designing a large-scale fracturing construction scheme for deep thermal reservoirs based on weak structures is characterized in that the steps include:

[0006] The weak structure of the deep thermal reservoir scale fracturing formation is characterized and represented to obtain a comprehensive characterization large model; the comprehensive characterization large model includes: a deep thermal reservoir porosity and permeability evolution model, a deep thermal reservoir physical property characteristic model, a deep thermal reservoir mechanical property evolution model with temperature, a well reservoir geological model, a site-scale deep thermal reservoir three-dimensional geological model, a multi-scale embedded weak structure geological model and a rock mechanics constitutive model;

[0007] Based on the comprehensive characterization large model, the weak structural zone of the deep thermal reservoir scale fracturing formation is delineated and the fracturing property is evaluated to obtain the delineated area;

[0008] Based on the delineated area, predict the farthest disturbance range and distance of fracturing and reconstruction of weak structures of deep thermal reservoir-scale fracturing formations;

[0009] Based on the farthest disturbance range and distance of fracturing transformation of weak structure of deep thermal reservoir by large-scale fracturing, the well spacing, well location design, well network deployment and optimal fracturing layer section are determined to complete the design of large-scale fracturing construction plan for deep thermal reservoir.

[0010] Preferably, in the comprehensive characterization macromodel,

[0011] The deep thermal reservoir porosity evolution model is used to characterize the distribution of thermal storage properties at laboratory scale;

[0012] The deep heat storage physical property characteristic model is used to characterize the distribution of physical characteristics of laboratory-scale heat storage at high temperatures;

[0013] The model of evolution of deep heat storage mechanical properties with temperature is used to characterize the distribution of deep heat storage mechanical characteristics at laboratory scale under high temperature;

[0014] The well reservoir geological model is used to characterize the distribution characteristics of well reservoir scale heat reservoir;

[0015] The site-scale deep heat reservoir three-dimensional geological model is used to analyze and interpret accurate information on deep heat reservoir scale fracturing formations of different types and scales of heat reservoirs;

[0016] The multi-scale embedded weak structure geological model is used to locate and characterize weak structures of different types and scales;

[0017] The rock mechanics constitutive model is used to characterize the complex weak structural characteristics of deep heat reservoirs.

[0018] Preferably, the delineation method includes: using the comprehensive characterization large model to analyze heat reservoir parameters, studying nonlinear evaluation methods for deep heat reservoirs, evaluating the quality and weakness of heat reservoirs, and completing the delineation of weak structural zones of deep heat reservoir-scale fracturing formations.

[0019] Preferably, the method for evaluating fracturability includes: establishing a mechanical brittleness index model that reflects the characteristics of the entire process of rock deformation and destruction, analyzing the brittleness, activation conditions and expansion methods of the weak structure of the thermal reservoir, and obtaining the fracturability of the weak structure of the deep thermal reservoir-scale fracturing formation based on the rock brittleness, development characteristics of the weak structure and the distribution of ground stress.

[0020] Preferably, based on the comprehensive characterization large model and combined with triaxial fracturing experiments, the farthest disturbance range and distance of thermal reservoir fracturing transformation are predicted.

[0021] The present invention also provides a deep thermal reservoir large-scale fracturing construction scheme design system based on weak structure, the system is used to implement the above method, including: a construction module, a delineation module, a prediction module and a design module;

[0022] The construction module is used to characterize and characterize the weak structure of the deep thermal reservoir scale fractured formation to obtain a comprehensive characterization large model;

[0023] The delineation module is used to delineate and evaluate the fracturing properties of the weak structural zone of the deep thermal reservoir scale fracturing formation based on the comprehensive characterization large model to obtain the delineated area;

[0024] The prediction module is used to predict the farthest disturbance range and distance of the fracturing transformation of the weak structure of the deep thermal reservoir scale fracturing formation based on the delineated area;

[0025] The design module is used to determine the well spacing, design the well location, deploy the well network and optimize the fracturing layer section based on the farthest disturbance range and distance of the fracturing transformation of the weak structure of the deep thermal reservoir large-scale fracturing formation, and complete the design of the deep thermal reservoir large-scale fracturing construction plan.

[0026] Preferably, the comprehensive characterization large model includes: a deep heat reservoir porosity evolution model, a deep heat reservoir physical property characteristic model, a deep heat reservoir mechanical property evolution model with temperature, a well reservoir geological model, a site-scale deep heat reservoir three-dimensional geological model, a multi-scale embedded weak structure geological model and a rock mechanics constitutive model;

[0027] The deep thermal reservoir porosity evolution model is used to characterize the distribution of thermal storage properties at laboratory scale;

[0028] The deep heat storage physical property characteristic model is used to characterize the distribution of physical characteristics of laboratory-scale heat storage at high temperatures;

[0029] The model of evolution of deep heat storage mechanical properties with temperature is used to characterize the distribution of deep heat storage mechanical characteristics at laboratory scale under high temperature;

[0030] The well reservoir geological model is used to characterize the distribution characteristics of well reservoir scale heat reservoir;

[0031] The site-scale deep heat reservoir three-dimensional geological model is used to analyze and interpret accurate information on deep heat reservoir scale fracturing formations of different types and scales of heat reservoirs;

[0032] The multi-scale embedded weak structure geological model is used to locate and characterize weak structures of different types and scales;

[0033] The rock mechanics constitutive model is used to characterize the complex weak structural characteristics of deep heat reservoirs.

[0034] The beneficial effects of the present invention are:

[0035] Through the construction and analysis of a comprehensive characterization large model, the present invention can accurately delineate the weak structural zones of the formation suitable for fracturing, predict the maximum disturbance range and distance of fracturing transformation, thereby optimizing the well site design, well network deployment and selection of fracturing layers, and achieving efficient mining under low-displacement and low-intensity fracturing conditions, significantly improving the development efficiency and safety of deep thermal storage resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solution of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0037] Figure 1 A schematic diagram of a multi-scale embedded weak structure geological model according to an embodiment of the present invention;

[0038] Figure 2 Schematic diagram of the correlation model between the geophysical field and the mechanical characteristics of the geothermal reservoir according to an embodiment of the present invention. DETAILED DESCRIPTION

[0039] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0040] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0041] Embodiment 1

[0042] The method for designing a large-scale fracturing construction scheme for deep thermal reservoirs based on weak structures in this embodiment includes the following steps:

[0043] S1. Characterize and characterize the weak structure of deep thermal reservoir-scale fracturing formations to obtain a comprehensive characterization model.

[0044] Specifically, this embodiment simulates the weak structure of deep thermal reservoir scale fracturing formation (hereinafter referred to as weak structure) in the laboratory, and then characterizes and represents it. Among them, the comprehensive characterization model includes: deep thermal reservoir porosity evolution model, deep thermal reservoir physical property characteristic model, deep thermal reservoir mechanical property evolution model with temperature, well reservoir geological model, multi-scale embedded weak structure geological model and rock mechanics constitutive model.

[0045] Specifically, through high-energy CT real-time scanning and triaxial experiments, a three-dimensional reconstruction technology is used to build a visualization numerical model of deep heat storage, combined with high-temperature and high-pressure servo permeability experiments, the visualization numerical model is optimized, and a deep heat storage porosity and permeability evolution model containing temperature and pressure parameters is constructed; and the deep heat storage porosity and permeability evolution model is used to characterize and characterize the distribution of laboratory-scale heat storage properties. Specifically, by testing the porosity and permeability parameters of deep heat storage under different temperature and pressure conditions, the porosity and permeability parameters under different conditions are fitted, and the evolution law of the porosity and permeability of deep heat storage with temperature and pressure parameters is obtained.

[0046] In this embodiment, the triaxial test steps include: placing the sample in a triaxial fracturing system and sealing it, heating it at a fixed rate, keeping it warm and pressurizing it according to preset conditions, and then injecting fracturing fluid for fracturing.

[0047] The steps of the high temperature and high pressure servo permeability test include: sealing the sample and placing it in the servo permeability test system, heating and keeping warm, applying axial load, confining pressure and pore pressure respectively, and forming an osmotic pressure difference at both ends of the sample by adjusting the pore pressure control system to complete the permeability test of the sample under high temperature and high pressure conditions.

[0048] Through cross-band rock physics experiments, the changes of thermal reservoir longitudinal and transverse wave velocity, resistivity, magnetism, polarizability, density and elastic parameters with temperature and pressure are studied, a deep thermal reservoir physical property characteristic model is established, and the distribution of laboratory-scale thermal reservoir physical characteristics at high temperature is described and characterized. Specifically, the steps of cross-band rock physics experiments include: using a cross-band rock parameter test system to measure the seismic wave velocity and ultrasonic wave velocity of the sample at different frequency bands, and calculating various rock parameters.

[0049] The deep thermal storage characteristics model is essentially obtained by conducting cross-band rock physics experiments at different temperatures to obtain various parameters under different temperature and pressure conditions, such as longitudinal and transverse wave velocities, resistivity, magnetism, polarizability, density and elastic parameters. The parameters are fitted with the changes in temperature and pressure conditions to obtain the corresponding formulas and then connected in parallel to obtain the deep thermal storage characteristics model.

[0050] Based on the analysis of indoor tests, the outcrop, drilling, logging and field test data are integrated to identify and interpret the structure of the well storage medium, establish a well storage geological model, and describe and characterize the distribution characteristics of the well storage scale heat storage. Specifically, based on the outcrop, drilling and logging, field test data, etc., a three-dimensional geological model can be initially constructed, the well location can be confirmed, and a well storage geological model can be established.

[0051] Based on rock physics experiments, logging data analysis, forward and inversion simulation, constrained inversion, geophysical structural interpretation, weak structural surface characterization and attribute analysis, the fine structural characteristics of deep heat reservoirs are obtained, and a three-dimensional geological model of deep heat reservoirs at the site scale is established. The specific steps include:

[0052] Through rock physics experimental tests, the physical and mechanical parameters of deep thermal reservoirs, such as tensile strength, compressive strength, porosity and permeability, can be obtained to provide mechanical parameter support for the model; through logging data, not only can thermal parameters such as thermal conductivity of the thermal reservoir be obtained, but also the thermal structure of the thermal reservoir can be comprehensively inferred through a variety of logging parameters; through forward and inverse simulation, constrained inversion, etc., the electrical characteristics, gravity and magnetic field characteristics, and geothermal field characteristics of the thermal reservoir can be quantitatively analyzed and calculated, providing parameter support for explaining the mechanism of thermal reservoir formation and evaluating resource quantities; through geophysical structural interpretation, weak structural surface characterization, etc., the weak structure of the thermal reservoir can be located with high precision to improve the accuracy of the three-dimensional geological model.

[0053] The established site-scale three-dimensional geological model of deep heat reservoirs is used to analyze and interpret precise information on weak structures of different types and scales, including spatial distribution, geometric shape, development density, scale, burial depth, superposition and contact relationship.

[0054] Using finite difference, finite element, finite volume method, etc., a multi-scale embedded weak structure geological model is constructed, such as Figure 1 As shown. Compared with the traditional model, the multi-scale embedded weak structure geological model uses an unstructured grid method to characterize fractures, avoiding the cumbersome problem of unstructured grid subdivision in traditional modeling, and qualitatively analyzing the distribution of weak structures with higher accuracy. This embodiment uses the finite element method to construct a multi-scale embedded weak structure geological model. The finite element method is a traditional numerical method that treats weak structures as the boundaries of the grid. The structural matrix displacement method is an early prototype of the finite element method, and the weighted residual finite element method and the variational principle finite element method were subsequently developed. Among them, the Galerkin finite element method is a typical representative of the weighted residual method. It is generally based on the stress equilibrium equation. First, the displacement field is solved, then the strain and stress field at the Gaussian point are calculated, and then the results at the Gaussian point are extended to the grid nodes.

[0055] Aiming at the complex weak structural characteristics (fracture type, crack-pore type, pore type, hole type, crushing type, joint type, etc.), based on the effective medium (EMT) theory, the parallel superposition calculation method of pore and matrix strain is adopted to establish the rock mechanics constitutive model of discontinuous heat storage medium under high temperature. Specifically, according to the theory of elastic mechanics, the strain field conforms to the superposition principle. When constructing the rock constitutive model, the superposition principle of the strain field is also applied. The total strain is equal to the sum of the strains caused by each stress. By determining the boundary conditions of various weak structures, the distribution of stress and strain can be confirmed. The strains of various weak structures are calculated in parallel and superposed, and the mechanical constitutive model of discontinuous heat storage medium can be constructed.

[0056] S2. Based on the comprehensive characterization large model, the weak structural zone of the deep thermal reservoir scale fracturing formation is delineated and the fracturing performance is evaluated to obtain the delineated area.

[0057] Based on the comprehensive characterization model established by S1, the obtained heat reservoir parameters are analyzed, the nonlinear evaluation method of deep heat reservoir is studied, the quality and weakness of heat reservoir are evaluated, and the weak structural zone where large-scale fracturing can be implemented under the existing technical conditions is delineated to obtain the delineated area. Among them, the heat reservoir parameters include all the mechanical parameters, thermal parameters, electrical parameters, etc. obtained through indoor experiments, logging, drilling and field tests, forward and inversion.

[0058] The steps of the nonlinear evaluation method for deep heat reservoirs include: confirming the heat reservoir area, thickness, temperature, porosity, rock density, etc. through the obtained parameters, calculating the geothermal reserves and recoverable amounts of different layers of the model in sections, and calculating the production capacity based on the recoverable amounts. In this embodiment, the standards for evaluating the quality and weakness of the heat reservoir refer to the "Geothermal Resource Evaluation Method" and the "Geothermal Resource Geological Exploration Specifications".

[0059] S3. Based on the delineated area, predict the farthest disturbance range and distance of fracturing transformation of weak structures of deep thermal reservoirs by large-scale fracturing.

[0060] In the demarcated area, combined with the triaxial fracturing experiment, the farthest possible disturbance range / distance of thermal reservoir fracturing transformation is predicted. The specific steps are as follows:

[0061] S301. Using a customized high-temperature and high-pressure multi-field coupling experimental system for geothermal reservoir rocks, triaxial compression experiments were carried out under different temperature and pressure conditions, and acoustic emission, wave velocity and deformation (axial and circumferential) were monitored simultaneously. Based on stress-strain, acoustic emission and wave velocity data, the mechanical properties and their evolution laws of geothermal reservoir rocks under high-temperature and high-pressure conditions, such as triaxial compressive strength, deformation modulus, Poisson's ratio, plasticity coefficient, elastic wave velocity and dynamic elastic modulus, were clarified;

[0062] S302. Based on the equivalent medium theory and different mechanical parameter data, a geothermal reservoir rock mechanical property evolution model with temperature parameters is established, and the correlation and constitutive relationship between the mechanical properties of geothermal reservoir rocks under high temperature are constructed; the expression of the geothermal reservoir rock mechanical property evolution model with temperature parameters is as follows:

[0063] ,

[0064] Where T and T0 represent temperature and initial temperature respectively. represents the bulk modulus of rock, represents the thermal expansion coefficient of rock, represents thermal conductivity, t represents time, and εT represents volume strain; is the specific heat capacity of water, represents the specific heat capacity of the rock skeleton, represents the specific heat capacity of the porous medium containing fluid, k represents the permeability of the continuous medium, μ represents the dynamic viscosity of the fluid, represents the gradient operator, Represents the pressure gradient.

[0065] S303. Based on the stress-strain relationship, according to the results obtained in S301-S302 or by applying known elastic models to perform calculations, establish elastic mechanics equations, solve the stress distribution inside the geothermal reservoir rock under different temperature and pressure conditions, and determine the magnitude and direction of stress disturbance;

[0066] S304. Combined with S301-S303, study the correlation between the physical and mechanical properties of geothermal reservoir rocks, obtain empirical formulas that use physical parameters to characterize rock mechanical parameters, and calibrate and invert geophysical parameters of geothermal reservoir mechanical properties at the site scale;

[0067] S305. Analyze the relationship between the mechanical characteristics of geothermal reservoirs and the response of multi-element geophysical fields by correlating the mechanical characteristics of hot dry rock reservoirs with geophysical properties under high temperature and high pressure;

[0068] S306. Based on S301-S305, establish a correlation model between the geophysical field and the mechanical characteristics of the geothermal reservoir (such as Figure 2 As shown in the figure, combined with the equivalent medium theory, the variation law of the mechanical properties of geothermal reservoirs at the site scale with temperature is clarified, and the possible farthest disturbance range / distance of reservoir fracturing transformation is estimated.

[0069] S4. Based on the farthest disturbance range and distance of fracturing transformation of weak structures in deep thermal reservoirs, determine the well spacing, design well locations, deploy well networks and optimize fracturing layers to complete the design of deep thermal reservoir large-scale fracturing construction plan.

[0070] S401. Deploy wells along the long axis direction or the strike of the original weak structural surface according to the spatial distribution range and shape of the identified weak structural zone;

[0071] S402. Based on the predicted or estimated maximum disturbance range / distance L of reservoir fracturing, considering the uncertainty of estimation accuracy and the objective requirement of easy connectivity between wells, it is assumed that the disturbance range between two adjacent wells has a 20% overlap section, and the well spacing R can be determined to be approximately:

[0072] R = (L + L) × 80%,

[0073] And deploy well patterns throughout the weak structural zone;

[0074] S403. Optimize the fracturing layer section based on the buried depth of the weak structural zone at the designed well location.

[0075] Embodiment 2

[0076] This embodiment also provides a deep heat storage large-scale fracturing construction plan design system based on weak structure, including: a construction module, a delineation module, a prediction module and a design module; the construction module is used to characterize and characterize the weak structure of the deep heat storage large-scale fracturing formation to obtain a comprehensive characterization large model; the delineation module is used to delineate and evaluate the fracturing properties of the weak structure zone of the deep heat storage large-scale fracturing formation based on the comprehensive characterization large model to obtain a delineated area; the prediction module is used to predict the farthest disturbance range and distance of the fracturing transformation of the weak structure of the deep heat storage large-scale fracturing formation based on the delineated area; the design module is used to determine the well spacing, design the well location, deploy the well network and optimize the fracturing layer section based on the farthest disturbance range and distance of the fracturing transformation of the weak structure of the deep heat storage large-scale fracturing formation, and complete the design of the deep heat storage large-scale fracturing construction plan.

[0077] The above-mentioned comprehensive characterization large model includes: deep heat reservoir porosity and permeability evolution model, deep heat reservoir physical property characteristic model, deep heat reservoir mechanical property evolution model with temperature, well reservoir geological model, site-scale deep heat reservoir three-dimensional geological model, multi-scale embedded weak structure geological model and rock mechanics constitutive model; the deep heat reservoir porosity and permeability evolution model is used to characterize the distribution of laboratory-scale heat reservoir physical property characteristics; the deep heat reservoir physical property characteristic model is used to characterize the distribution of laboratory-scale heat reservoir physical characteristics under high temperature; the deep heat reservoir mechanical property evolution model with temperature is used to characterize the distribution of laboratory-scale deep heat reservoir mechanical characteristics under high temperature; the well reservoir geological model is used to characterize the distribution characteristics of well reservoir scale heat reservoir; the site-scale deep heat reservoir three-dimensional geological model is used to analyze and interpret the precise information of deep heat reservoir scale fracturing strata of different types and scales of heat reservoirs; the multi-scale embedded weak structure geological model is used to locate and characterize weak structures of different types and scales; the rock mechanics constitutive model is used to characterize the complex weak structure characteristics of deep heat reservoirs.

[0078] The embodiments described above are only descriptions of the preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for designing a large-scale fracturing construction scheme for deep thermal reservoirs based on weak structures, characterized in that the steps include: Characterize and characterize the weak structure of deep thermal reservoir-scale fractured formations to obtain a comprehensive characterization large model; The comprehensive characterization large model includes: a deep heat reservoir porosity evolution model, a deep heat reservoir physical property characteristic model, a deep heat reservoir mechanical property evolution model with temperature, a well reservoir geological model, a site-scale deep heat reservoir three-dimensional geological model, a multi-scale embedded weak structure geological model and a rock mechanics constitutive model; Based on the comprehensive characterization large model, the weak structural zone of the deep thermal reservoir scale fracturing formation is delineated and the fracturing property is evaluated to obtain the delineated area; Based on the delineated area, predict the disturbance range and distance of fracturing reconstruction of weak structures of deep thermal reservoir-scale fracturing formations; Based on the disturbance range and distance of fracturing transformation of weak structure of deep thermal reservoirs by large-scale fracturing, the well spacing, well location, well network and fracturing layer section are determined to complete the design of large-scale fracturing construction plan for deep thermal reservoirs.

2. The method for designing a large-scale fracturing construction scheme for deep thermal storage based on weak structure according to claim 1, characterized in that: In the comprehensive characterization model, The deep thermal reservoir porosity evolution model is used to characterize the distribution of thermal storage properties at laboratory scale; The deep heat storage physical property characteristic model is used to characterize the distribution of physical characteristics of heat storage at laboratory scale; The model of evolution of mechanical properties of deep heat reservoirs with temperature is used to characterize the distribution of mechanical characteristics of deep heat reservoirs at laboratory scale; The well reservoir geological model is used to characterize the distribution characteristics of well reservoir scale heat reservoir; The site-scale deep heat reservoir three-dimensional geological model is used to analyze and interpret accurate information on deep heat reservoir scale fracturing formations of different types and scales of heat reservoirs; The multi-scale embedded weak structure geological model is used to locate and characterize weak structures of different types and scales; The rock mechanics constitutive model is used to characterize the complex weak structural characteristics of deep heat reservoirs.

3. The method for designing a large-scale fracturing construction scheme for deep thermal storage based on weak structure according to claim 1, characterized in that: The delineation method includes: using the comprehensive characterization large model to analyze heat reservoir parameters, studying the nonlinear evaluation method of deep heat reservoirs, evaluating the quality and weakness of heat reservoirs, and completing the delineation of weak structural zones of deep heat reservoir scale fracturing formations.

4. The method for designing a large-scale fracturing construction scheme for deep thermal storage based on weak structure according to claim 1, characterized in that: The methods for evaluating fracturing properties include: establishing a mechanical brittleness index model that reflects the characteristics of the entire process of rock deformation and destruction, analyzing the brittleness, activation conditions and expansion methods of the weak structure of the thermal reservoir, and obtaining the fracturing properties of the weak structure of the deep thermal reservoir formation based on the rock brittleness, development characteristics of the weak structure and the distribution of ground stress.

5. The method for designing a large-scale fracturing construction scheme for deep thermal reservoirs based on weak structures according to claim 1, characterized in that: Based on the comprehensive characterization large model and combined with triaxial fracturing experiments, the disturbance range and distance of thermal reservoir fracturing transformation are predicted.

6. A system for designing large-scale fracturing construction schemes for deep thermal reservoirs based on weak structures, the system being used to implement the method described in any one of claims 1 to 5, characterized in that: include: Building module, delineating module, predicting module and designing module; The construction module is used to characterize and characterize the weak structure of the deep thermal reservoir scale fractured formation to obtain a comprehensive characterization large model; The delineation module is used to delineate and evaluate the fracturing properties of the weak structural zone of the deep thermal reservoir scale fracturing formation based on the comprehensive characterization large model to obtain the delineated area; The prediction module is used to predict the disturbance range and distance of the fracturing transformation of the weak structure of the deep thermal reservoir scale fracturing formation based on the delineated area; The design module is used to determine the well spacing, design the well location, deploy the well network and the fracturing layer section based on the disturbance range and distance of the fracturing transformation of the weak structure of the deep thermal reservoir large-scale fracturing formation, and complete the design of the deep thermal reservoir large-scale fracturing construction plan.

7. The deep thermal storage large-scale fracturing construction scheme design system based on weak structure according to claim 6 is characterized in that: The comprehensive characterization large model includes: a deep heat reservoir porosity evolution model, a deep heat reservoir physical property characteristic model, a deep heat reservoir mechanical property evolution model with temperature, a well reservoir geological model, a site-scale deep heat reservoir three-dimensional geological model, a multi-scale embedded weak structure geological model and a rock mechanics constitutive model; The deep thermal reservoir porosity evolution model is used to characterize the distribution of thermal storage properties at laboratory scale; The deep heat storage physical property characteristic model is used to characterize the distribution of physical characteristics of laboratory-scale heat storage at high temperatures; The model of evolution of deep heat storage mechanical properties with temperature is used to characterize the distribution of deep heat storage mechanical characteristics at laboratory scale under high temperature; The well reservoir geological model is used to characterize the distribution characteristics of well reservoir scale heat reservoir; The site-scale deep heat reservoir three-dimensional geological model is used to analyze and interpret accurate information on deep heat reservoir scale fracturing formations of different types and scales of heat reservoirs; The multi-scale embedded weak structure geological model is used to locate and characterize weak structures of different types and scales; The rock mechanics constitutive model is used to characterize the complex weak structural characteristics of deep heat reservoirs.

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