A platform for geostress analysis

Abstract

The application discloses a geo-stress analysis platform, and relates to the cross technical field of geology engineering and computers. The geo-stress analysis platform comprises a geo-stress database module, a data preprocessing module, a calculation and analysis module, a drawing and statistics module, a report export module and a tool set module. The geo-stress database module is used for storing, querying and updating various test data. The data preprocessing module is used for cleaning data, converting data formats and standardizing abnormal values to obtain preprocessed data. The calculation and analysis module is used for integrating various analysis methods such as hydraulic fracturing, and supporting automatic calculation and manual parameter adjustment. The drawing and statistics module is used for generating various charts such as stress distribution and stress ratio distribution according to analysis results. The report export module is used for outputting structured document reports. The tool set module is used for realizing diversified data processing and analysis by using various tools, and provides a complete solution for efficient analysis of geo-stress test data and output of achievements.

Description

Technical Field

[0001] This invention relates to the interdisciplinary field of geological engineering and computer science, and in particular to a geostress analysis platform. Background Technology

[0002] In fields such as earthquake science research, energy resource development, and underground space utilization, geostress is a key parameter. Currently, various methods exist for geostress testing, such as hydraulic fracturing, inelastic strain recovery, and stress relief methods. However, the raw data obtained by these methods are not uniformly formatted, and the analysis processes are cumbersome. Although some geostress analysis tools exist abroad, their functions are relatively limited, lacking a professional and practical analysis platform that integrates database management, preprocessing, calculation and analysis, plotting and statistical analysis, and report export for various types of geostress test data. Summary of the Invention

[0003] To overcome the shortcomings of existing technologies, the purpose of this invention is to provide an integrated geostress analysis platform to address the problems of limited functionality, fragmented data management, and cumbersome analysis processes in current geostress analysis tools. This platform integrates geostress database management, data preprocessing, calculation and analysis using multiple methods, plotting and statistics, and report export functions, achieving centralized management and efficient analysis of geostress data. Furthermore, the platform adopts a cloud architecture to support multi-user collaboration, and its interface design draws on the advantages of mature software, improving user experience and work efficiency, thus providing a comprehensive geostress analysis solution for fields such as earthquake research, energy development, and underground space utilization.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] A geostress analysis platform, comprising:

[0006] The geostress database module is configured to centrally store, query, and update various geostress test data.

[0007] The data preprocessing module is configured to perform data cleaning, format conversion, and outlier standardization on various types of geostress test data stored in the geostress database module to obtain preprocessed data.

[0008] The calculation and analysis module integrates multiple geostress analysis methods to generate analysis results, including hydraulic fracturing, three-dimensional hydraulic fracturing, inelastic strain recovery, and stress relief methods, and supports a combination of automatic calculation and manual parameter adjustment.

[0009] The plotting and statistics module is configured to generate stress distribution diagrams, stress ratio distribution diagrams, scatter plots of horizontal principal stress directions, and rose diagrams of horizontal principal stress directions based on the analysis results of the calculation and analysis module.

[0010] The report export module is configured to output the analysis results of the calculation and analysis module as a structured document report;

[0011] The toolset module includes a file renaming / data reorganization tool, a crack imprint simulation tool, a stress polygon analysis tool, and a four-component piezomagnetic geostress data analysis tool, which are used to enable diverse processing and analysis of various geostress test data.

[0012] Preferably, in the above-mentioned geostress analysis platform, the calculation and analysis module includes a hydraulic fracturing module, a three-dimensional hydraulic fracturing module, an inelastic strain recovery method calculation module, and a stress relief calculation module. The hydraulic fracturing module, the three-dimensional hydraulic fracturing module, the inelastic strain recovery method calculation module, and the stress relief calculation module are used to execute the hydraulic fracturing method, the three-dimensional hydraulic fracturing method, the inelastic strain recovery method, and the stress relief method, respectively.

[0013] Preferably, in the above-mentioned geostress analysis platform, the hydraulic fracturing module is configured as follows:

[0014] The evolution trend of the overall system stiffness is used to identify the crack closure process and determine the upper and lower limits of the closure pressure; wherein, the evolution trend of the overall system stiffness is estimated using measured pressure-time data and the following formula:

[0015] ;

[0016] In the formula, S t Let P be the total stiffness of the system and P be the fluid pressure in the measuring section. t Let P(i) and P(i-1) be the time intervals, respectively, where P(i) and P(i-1) are the i-th and (i-1)-th time intervals. τ The corresponding pressure, S t ′ represents the dimensionless overall system stiffness. i For each time interval τ The index number, where n is the total number of time intervals. P p To measure the pore pressure of the rock mass, V L For the fluid leakage volume, V To analyze the volume, C This is a C function describing the pressure decay phase. V L The relative trend of change.

[0017] Preferably, in the above-mentioned geostress analysis platform, the hydraulic fracturing module is configured as follows:

[0018] Identify pressure-time data from multiple iterations during the experiment;

[0019] For each cycle, based on a preset characteristic slope threshold, three key characteristic moments within that cycle are automatically identified: the pump start-up moment, the pump stop-up moment, and the pressure relief moment. The pump start-up moment, the pump stop-up moment, and the pressure relief moment serve as the endpoints of the time interval required to calculate the key characteristic pressure parameters of ground stress. The characteristic slope threshold is set based on the data characteristics of the pump start-up moment, the pump stop-up moment, and the pressure relief moment, and has an adjustable initial value.

[0020] Preferably, in the above-mentioned geostress analysis platform, the inelastic strain recovery method calculation module is configured as follows:

[0021] Obtain ASR test data for the minimum horizontal principal stress and different k values ​​determined by the HF method; wherein, the k value is the inelastic strain recovery compliance ratio.

[0022] The minimum horizontal principal stress is calculated based on the ASR test data when k=0. The minimum horizontal principal stress is compared with the minimum horizontal principal stress measured by the HF method. If the difference between the two is greater than a set threshold, the value of k is increased by a set step size, and the minimum horizontal principal stress is recalculated until the difference between the minimum horizontal principal stress and the minimum horizontal principal stress measured by the HF method is at the set threshold, and the value of k is determined.

[0023] Based on the determined value of k, and combined with the equation relating vertical stress to the weight of the overlying strata, the corresponding volumetric mode inelastic strain recovery compliance is calculated. Jav (t) and shear mode inelastic strain recovery compliance Jas (t), and the values ​​of the maximum principal stress, intermediate principal stress, minimum principal stress, maximum horizontal principal stress, minimum horizontal principal stress and vertical stress are calculated based on the inelastic strain recovery strain data of the salt rock.

[0024] Preferably, in the above-mentioned geostress analysis platform, the equation relating the vertical stress to the weight of the overlying strata is expressed as:

[0025] ;

[0026] In the formula, l p , m p , n p These are the direction cosines between the vertical stress and the three principal strain axes, respectively. h To test the burial depth of the rock core samples, ρ The average density of rock from the surface to this depth. g It is the acceleration due to gravity. P 0 represents pore pressure. e m (t) represents the strain of the inelastic body. e1( t ), e 2( t )and e 3( t () represent the inelastic deviatoric strains along the three principal strain axes, respectively. This represents vertical stress.

[0027] Preferably, in the above-mentioned geostress analysis platform, the expression for the value of k is:

[0028] ;

[0029] In the formula, Jas (t) represents the inelastic strain recovery compliance in shear mode; Jav (t) represents the volumetric mode inelastic strain recovery compliance.

[0030] Preferably, in the above-mentioned geostress analysis platform, the calculation formulas for the values ​​of the maximum principal stress, intermediate principal stress, minimum principal stress, maximum horizontal principal stress, minimum horizontal principal stress, and vertical stress, calculated based on the inelastic strain recovery strain data of salt rock, are as follows:

[0031] ;

[0032] ;

[0033] ;

[0034] In the formula, ε a It is an inelastic recovering strain; l , m , n The direction cosine of the strain axis; σ x , σ y , σ z , τ xy , τ yz ,τ zx These are stress components; σ m The average stress; P 0 represents pore pressure; α T Δ is the linear thermal expansion coefficient; T (t) represents the temperature change during the measurement period; σ i Principal stress, e i (t) represents the inelastic deviatoric strain. em (t) represents the strain of the inelastic body; i = 1, 2, 3; σ h For the minimum horizontal principal stress, σ x and σ y These represent the normal stress components along two mutually perpendicular coordinate axes in the horizontal direction. τ xy Let be the shear stress components in the xy plane.

[0035] Preferably, in the above-mentioned geostress analysis platform, the platform adopts a cloud platform architecture, which supports multiple users to operate online simultaneously.

[0036] Preferably, in the above-mentioned geostress analysis platform, the stress polygon tool in the toolset module performs the following functions:

[0037] Stress normalization and thermal stress calculation;

[0038] Constraint line analysis and multi-stress state projection;

[0039] Automatically generate stress polygon base maps for tunnel stability assessment.

[0040] The beneficial effects of this invention: Compared with the prior art, this invention has the following technical advantages:

[0041] (1) Improve work efficiency: The integrated functions of geostress database management, data preprocessing, calculation and analysis by multiple methods, drawing statistics and report export, etc., eliminate the need for users to frequently switch between different software and tools, which significantly improves work efficiency.

[0042] (2) Improve data management efficiency: Centralize the management of various types of geostress test data, support data storage, query and update, ensure data integrity and traceability, and facilitate users to quickly obtain and manage geostress data.

[0043] (3) Enhanced analysis flexibility: Provides a variety of geostress analysis methods and tools, allowing users to flexibly select analysis methods according to actual project needs and data characteristics, and supports manual adjustment and custom modeling to adapt to the specific needs and special scenarios of different users.

[0044] (4) Data visualization: The rich drawing tools and chart types make the analysis results more intuitive and easy to understand, enabling users to quickly grasp the characteristics and patterns of stress distribution and provide strong support for decision-making.

[0045] (5) Support for multi-user collaboration: The cloud platform architecture supports multiple users to operate online at the same time, which facilitates team collaboration and data sharing and improves the overall work efficiency of the team.

[0046] (6) Reduced learning cost: The interface design draws on the advantages of mature software, providing an intuitive and convenient operating experience, reducing the user's learning cost, and enabling users to quickly get started and master various functions. Due to the different calculation principles of geostress testing methods, the platform can bring great convenience and reliability to users who are not familiar with the complex calculation principles of analytical methods.

[0047] (7) Improve data processing efficiency: The automated processing function reduces the error caused by manual operation and improves the accuracy and consistency of analysis. Especially when processing a large amount of data, it can quickly obtain preliminary analysis results.

[0048] (8) Promote technical exchange: Users can easily share data and analysis results on the platform, which promotes technical exchange and knowledge sharing within the team.

[0049] (9) It has versatility and scalability: The platform is applicable to multiple fields such as earthquake science research, energy resource development and underground space utilization, and can continuously add and improve functions as needed, and continuously maintain, automatically update and iterate, with good versatility and scalability. Attached Figure Description

[0050] Figure 1 A structural diagram of a geostress analysis platform provided in an embodiment of the present invention;

[0051] Figure 2 A technical framework diagram of the geostress analysis platform provided in the embodiments of the present invention;

[0052] Figure 3 The contents and structure diagram of the geostress analysis platform provided in the embodiments of the present invention;

[0053] Figure 4 A schematic diagram illustrating platform login and registration provided in an embodiment of the present invention;

[0054] Figure 5 A schematic diagram of the platform menu provided in an embodiment of the present invention;

[0055] Figure 6 A schematic diagram of the drawing toolbar provided in an embodiment of the present invention;

[0056] Figure 7 A schematic diagram illustrating image detail settings provided in an embodiment of the present invention;

[0057] Figure 8 This is a schematic diagram of the hydraulic fracturing module processing borehole test data provided in an embodiment of the present invention;

[0058] Figure 9 An example diagram illustrating the processing of test data by the three-dimensional hydraulic fracturing analysis module provided in this embodiment of the invention;

[0059] Figure 10 An example diagram illustrating the processing of test data by the inelastic strain recovery calculation module provided in this embodiment of the invention;

[0060] Figure 11 An example diagram illustrating the stress relief calculation module processing test data provided in this embodiment of the invention;

[0061] Figure 12 An example diagram illustrating the data processing of the triaxial experimental data analysis module included in the toolset provided in this embodiment of the invention;

[0062] Figure 13 An example diagram showing the data processed by the stress direction drawing module included in the toolset provided in this embodiment of the invention;

[0063] Figure 14 Example diagram of data processing by the stress polygon analysis module included in the toolset provided in the embodiments of the present invention;

[0064] Figure 15 The diagram shows the calculation results of the stress relief geostress analysis module provided in this embodiment of the invention.

[0065] Figure 16 A schematic diagram of the mechanical model for stress analysis of hydraulic fracturing;

[0066] Figure 17 A schematic diagram of picking up retension pressure using the tangent method based on the pressure-time curve provided in an embodiment of the present invention;

[0067] Figure 18 This is a schematic diagram of the tension picking method based on translation provided in an embodiment of the present invention;

[0068] Figure 19 A schematic diagram of the single tangent method provided for embodiments of the present invention (a. time window at a general scale; b. time window at a magnified scale);

[0069] Figure 20 A schematic diagram of the Muskat method provided in an embodiment of the present invention;

[0070] Figure 21 This is a schematic diagram of the dP / dT method provided in an embodiment of the present invention;

[0071] Figure 22 This is a schematic diagram of the dT / dP method provided in an embodiment of the present invention;

[0072] Figure 23 This is an idealized relationship curve between the overall system stiffness and the measured segment pressure during the pressure decay stage, provided in an embodiment of the present invention.

[0073] Figure 24A schematic diagram illustrating the calculation of closure pressure using the Total System Stiffness (TSS) method provided in this embodiment of the invention; where (j) and (k) represent calculation cases at different depths;

[0074] Figure 25 This is a schematic diagram illustrating the automatic identification of multiple key feature moments provided by an embodiment of the present invention;

[0075] Figure 26 A flowchart illustrating the ASR geostress testing method provided in this embodiment of the invention. Detailed Implementation

[0076] The specific embodiments of this invention are described in detail below with reference to the accompanying drawings. However, the scope of protection of this invention is not limited to the description of these embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without inventive effort are within the scope of protection of this invention.

[0077] This invention provides a geostress analysis platform, such as... Figure 1 As shown, the geostress analysis platform includes:

[0078] The geostress database module 10 is configured to centrally store, query, and update various geostress test data;

[0079] The data preprocessing module 20 is configured to perform data cleaning, format conversion and outlier standardization on various types of geostress test data stored in the geostress database module to obtain preprocessed data.

[0080] The calculation and analysis module 30 integrates multiple geostress analysis methods to generate analysis results, including hydraulic fracturing method, three-dimensional hydraulic fracturing method, inelastic strain recovery method and stress relief method, and supports a combination of automatic calculation and manual parameter adjustment;

[0081] The plotting and statistics module 40 is configured to generate stress distribution diagrams, stress ratio distribution diagrams, scatter plots of horizontal principal stress directions, and rose diagrams of horizontal principal stress directions based on the analysis results of the calculation and analysis module.

[0082] The report export module 50 is configured to output the analysis results of the calculation and analysis module as a structured document report;

[0083] Toolset Module 60 includes a file renaming / data reorganization tool, a crack imprint simulation tool, a stress polygon analysis tool, and a four-component piezomagnetic geostress data analysis tool, which are used to enable diverse processing and analysis of various geostress test data.

[0084] like Figure 2The diagram shown illustrates the technical framework of the geostress analysis platform provided in this embodiment of the invention. This platform adopts a cloud platform architecture, supporting simultaneous online operation by multiple users. Its interface design integrates the advantages of software such as QQ, WeChat, Origin, and Matlab, providing an intuitive and convenient user experience. Platform functions include geostress database management, data preprocessing, calculation and analysis using various methods, plotting and statistics, and report export. It also features a rich toolset, such as file renaming / data reconstruction, crack imprinting, and triaxial experimental data analysis, to meet the needs of different users. Through its integrated design, this platform can improve the efficiency and accuracy of geostress analysis, providing strong support for research and applications in related fields.

[0085] like Figure 3 As shown in this embodiment, the platform adopts a cloud platform architecture, supporting simultaneous online operation by multiple users. Its interface design integrates the advantages of software such as QQ, WeChat, Origin, and Matlab, providing an intuitive and convenient operating experience. The geostress database can efficiently store and retrieve geostress data, supporting centralized data management and sharing. The data preprocessing module can automatically remove invalid data and standardize the data, improving data quality. The calculation and analysis module supports multiple geostress analysis methods, allowing users to flexibly select analysis methods according to actual project needs and data characteristics, and supports manual adjustment and custom model creation. The plotting and statistics module provides rich plotting tools and chart types, making the analysis results more intuitive and easy to understand, facilitating users to quickly grasp the distribution characteristics and changing patterns of geostress. The report export module can export the analysis results as standardized Word reports, meeting users' requirements for standardized report format and content. The toolset includes various practical tools for diversified processing and analysis of geostress data, improving analysis efficiency and accuracy. The platform is applicable to multiple fields such as earthquake science research, energy resource development, and underground space utilization, and its functions can be continuously added and improved as needed, exhibiting good versatility and scalability.

[0086] like Figure 3The diagram shown illustrates the content and structure of the geostress analysis platform proposed in this embodiment of the invention. This platform includes a user module, a toolset, a geostress test data analysis module, a plotting module, and a data storage module. The user module covers functions such as registration and login, permission design, operation logs, and data sharing. The toolset includes tools such as stress Mohr's circle, stress polygon, regional stress field analysis, and triaxial experiments. The geostress test data analysis module involves modules such as hydraulic fracturing, three-dimensional hydraulic fracturing, stress relief, and inelastic strain. The plotting module includes functions such as plotting settings, copying and downloading, secondary editing, and cleaning and smoothing. The data storage module supports batch import, file format processing, batch export, and CRUD operations. It also mentions data classification management, geostress calculation result analysis, and export of results reports. The bottom layer is the storage layer.

[0087] In some embodiments, the geostress analysis platform is built on a cloud platform architecture, supporting simultaneous online operation by multiple users, allowing users to access and use the platform's functions from different locations via the network. The server side is responsible for data storage, processing, and task scheduling, while the client accesses the platform through a browser or dedicated client software.

[0088] The functions implemented by each module in this geostress analysis platform are as follows:

[0089] The geostress database centrally manages various geostress test data, supporting data storage, querying, updating, and backup. Its rationally designed database structure enables efficient storage and retrieval of geostress data, and facilitates regional stress field analysis.

[0090] The data preprocessing module provides functions such as data cleaning, format conversion, and outlier handling. For example, the data cleaning function automatically removes invalid data, which is selected by default in the system.

[0091] The calculation and analysis module integrates various geostress analysis methods, including hydraulic fracturing, three-dimensional hydraulic fracturing, inelastic strain recovery, and stress relief. Taking hydraulic fracturing as an example, users can create new borehole locations, upload borehole measurement data, and the platform will automatically perform preliminary analysis.

[0092] The plotting and statistics module provides a wealth of plotting tools, supporting the generation of various professional charts such as stress distribution diagrams, stress ratio distribution diagrams, scatter plots of horizontal principal stress directions, and rose diagrams of horizontal principal stress directions.

[0093] The report export module can export the analysis results as a Word report, which includes key information such as experimental curves for each test section, fracturing parameters, and principal stress calculation results.

[0094] In some embodiments, the geostress analysis platform also includes a feedback module and an automatic version update module.

[0095] In some embodiments, the geostress analysis platform integrates a user management and operation interface.

[0096] User Management: Supports user registration and login. Upon initial registration, users are required to enter their name and organization, facilitating information exchange and data access management within the platform. Different user permissions are set; highlighted measurement data points are viewable and editable, while grayed-out data points have restricted viewing access.

[0097] User Interface: The interface design draws on the advantages of software such as QQ, WeChat, Origin, and Matlab, providing an intuitive and convenient user experience. The main interface includes a map page, a borehole table page, a data analysis interface, and a results summary interface, all of which support double-click navigation.

[0098] The toolset is a crucial component of the platform, containing a variety of practical tools for diverse processing and analysis of geostress data. In some embodiments, the file renaming / data reorganization tool can perform batch logical renaming and data table reorganization of all files within a folder; the crack imprint tool enables random simulation and manual mouse drawing of hydraulically induced fracture imprints; the triaxial experimental data analysis tool supports the analysis and processing of triaxial experimental data; the azimuth plotter enables drawing geostress azimuth data in common formats; the tunnel stability analysis tool provides tunnel stability analysis functions; the stress polygon tool mainly implements functions such as stress polygon base map creation, stress normalization, thermal stress calculation, various types of point projection, and calculation of various constraint lines; the fitting tool supports multi-order fitting, including linear fitting, exponential fitting, and polynomial fitting, and allows users to customize models; the four-component piezomagnetic geostress monitoring data analysis tool enables the analysis of four-component piezomagnetic geostress monitoring data; the stress ellipse tool provides stress ellipse drawing functions; and the stress moiré circle tool enables the drawing and analysis of stress moiré circles.

[0099] In some embodiments, the data analysis process implemented by the geostress analysis platform is as follows:

[0100] Regional Data Analysis: Users can select specific areas by drawing rectangles in the borehole distribution module. The platform automatically loads and displays the geostress data for the selected area. Users can view various charts on the map as needed, such as horizontal stress direction diagrams, focal mechanism diagrams, earthquake distribution maps, and platform measuring point distribution maps with existing analysis results. The platform can also automatically draw stress distribution maps, stress ratio distribution maps, scatter plots of horizontal principal stress directions, and horizontal principal stress direction rose diagrams for the selected area.

[0101] Borehole Measurement Data Analysis: Users can access modules such as hydraulic fracturing, 3D hydraulic fracturing, inelastic strain, and stress relief to view and edit borehole data obtained using the corresponding methods. Taking hydraulic fracturing as an example, users can create new borehole locations and upload borehole measurement data including parameters such as surface pressure, injection flow rate, return flow rate, cumulative injection volume, and cumulative return flow rate. The platform provides a data cleaning function to automatically remove invalid data. Users can double-click the borehole depth data file in the right-hand view window to enter the editing interface. The software automatically generates images based on the borehole test data and automatically determines key parameters such as time, number of measurement cycles, fracturing pressure, re-tensioning pressure, and closure pressure by clicking the automatic calculation button. For cases with large curve fluctuations, users can manually determine the pump start-up, pump shutdown, and depressurization times, as well as the partial determination methods for re-tensioning pressure and closure pressure. Unnecessary curve segments in the image can be removed using the local deletion function, and the deleted data will no longer participate in parameter calculations, but the initial state can be restored by clicking the initial data. When the image curve fluctuates too much, users can choose the full smoothing or local smoothing function for processing to better analyze the data. After data processing is complete, users can click the "Save to Server" button in the file or use Ctrl+S to save the record. Once all calculations are complete, users can click the summary page in the right-hand view window to view the summary results. The direction of the maximum horizontal principal stress needs to be manually entered on this interface. Finally, users can export the geostress analysis report for the borehole, which includes key information such as experimental curves for each section, fracturing parameters, and principal stress calculation results.

[0102] For example, such as Figure 4 The diagram shows the login and registration process for the platform, illustrating the three interfaces of the geostress analysis platform. From left to right, they are: the login interface, which includes a username (e.g., "651696767"), a password input box, a "Registered" checkbox, a "Login" button, and links to "Forgot Password," "Register Account," and "User Agreement"; the password retrieval interface, which includes a "Please Enter Username" input box, "Get SMS Verification Code," "Verify Verification Code" buttons, a "Change Password" button, and a "Return to Login" link; and the registration interface, which requires users to fill in their username, login account, password, confirm password, company name, and contact email address. It also includes a "I have read and agree to the User Agreement" checkbox, and options to "Register Now" and "Already have an account? Return to Login." All interfaces are designed around the platform's account usage process.

[0103] like Figure 5The diagram shows the platform menu, with top-level menus including "File," "View," "Data Processing," "Tools," "Settings," and "Help." The "File" menu includes options such as "Create New Borehole / Survey Point," "Save to Server" (shortcut Ctrl+S), "Export Results," and "Exit." The "Data Processing" menu includes options such as "File Rename / Data Reset," "Crack Identification," "Triaxial Experiment Analysis," "Azimuth Detection," "Tunnel Surrounding Rock Stability Analysis," "Stress Polygon Fitting Tool," "Ground Stress-Strain Data Analysis," "Stress Ellipsoid," "Well Compilation," "Wellbore Stress Analysis," and "Safe Mud Window Analysis." The "Tools" menu includes settings for detection, borehole logging capacity, borehole logging capacity, and theme switching (subsystem theme, bright theme). The "Settings" menu includes user agreement, instructions, feedback, and an "About" section. It also includes a "Continuous Integration" section, illustrating the organizational relationship between the software's functional modules.

[0104] like Figure 6 The diagram shows the drawing toolbar, which, from left to right, includes: Reset View, Previous View, Next View, Drag Mode, Zoom Mode, Edit Margins, Edit Graphics, Create Graphics, Download Data, and Save Image. These tools are used to manipulate and process views or graphics.

[0105] like Figure 7 The diagram shown illustrates the image detail settings, displaying three interfaces related to basic drawing settings. These interfaces include drawing style (defaultStyle), which contains parameters such as line width, color, transparency, font, font size, and background color. These parameters are used to set the basic style attributes of the drawing, such as line style, text display, and graphic appearance, helping users customize the drawing effect.

[0106] In some embodiments, the calculation and analysis module includes a hydraulic fracturing module, a three-dimensional hydraulic fracturing module, an inelastic strain recovery method calculation module, and a stress relief calculation module. The hydraulic fracturing module, the three-dimensional hydraulic fracturing module, the inelastic strain recovery method calculation module, and the stress relief calculation module are used to execute the hydraulic fracturing method, the three-dimensional hydraulic fracturing method, the inelastic strain recovery method, and the stress relief method, respectively.

[0107] For example, such as Figure 8 The diagram shows the hydraulic fracturing module processing borehole test data. It displays the interface of the geostress test data analysis software, showing the relationship curve between pressure (MPa) and flow rate (L / min). It can automatically identify and analyze the 1st to 5th tests (currently the 3rd and 4th tests are selected), involving parameters such as pressure time and fracturing pressure, as well as closure pressure (such as -dP / dt, G-tangent, etc.) analysis, for the processing and interpretation of geostress test data.

[0108] like Figure 9The image shown is an example of test data processed by the three-dimensional hydraulic fracturing analysis module. It displays borehole data, such as the major / minor principal stress components, dip angle, dip direction, and azimuth angle of boreholes HF1, 2, and HF3. The middle part shows the polar coordinate graph of stress direction, including stress labels S1-S5 for different stress components. The right side shows the calculation results of each stress component, including 5 sets of principal stress data and calculation methods, which are used for geostress testing and analysis.

[0109] like Figure 10 The figure shown is an example of test data processed by the inelastic strain recovery method calculation module. The left side of the figure presents basic test information, including axial strain (%), confining pressure (MPa), lateral pressure (MPa), pore pressure (MPa), secondary axis azimuth (°), Δσ1 / Δσ3, borehole azimuth angle (°), borehole inclination angle (°), time interval (hour), core diameter (mm), and remarks. The middle part is a line graph showing the strain change over time [hour] (including ε2, ε3, ε0, ε...). m The curve has a strain gauge marked with ×10 on the vertical axis. -6 The bottom section shows the mean calculation results, displaying data such as principal stress (MPa), azimuth (°), and dip angle (°); the right side is the data input area.

[0110] like Figure 11 The image shows an example of the stress relief calculation module processing test data. Its interface layout is clear and used for data processing and analysis in stress relief tests. The basic information section details the test depth (20.00m), elastic modulus (35.00GPa, measuring the material's resistance to deformation), Poisson's ratio (0.30, reflecting the relationship between lateral and longitudinal deformation), RQD (core quality index, 0.00), probe installation angle (312.00°), borehole azimuth (180.00°, indicating borehole direction), borehole inclination (4.00°, reflecting the borehole's tilt), four correction coefficients (all 1.0000, used for data calibration), core location (0.00cm), and blank lithology and remarks columns, providing fundamental parameters for test analysis. The central area is a stress direction diagram in polar coordinates, with azimuth (N North, E East, S South, W West) as the reference, clearly marking S1 (maximum principal stress), S2 (intermediate principal stress), S3 (minimum principal stress), and S... h (Horizontal principal stress, etc.) visually presents the spatial distribution of stress. The data input area on the right is categorized into groups A, B, and C, listing the strain values ​​and output strain values ​​of 12 strain gauges. For example, strain gauge 1 in group A has a strain value of 1495.0 and an output strain value of 531.0, accurately collecting experimental data. The stress calculation results area below lists the stress components (such as S...) in a table. x S yThe interface clearly presents the calculated stress-related data, including principal stress values ​​(MPa, e.g., S1 value 24.74 MPa), azimuth (°, indicating stress direction), and inclination angle (°, reflecting stress tilt angle). The bottom of the interface includes a note stating "X-axis to the east, Y-axis to the north, Z-axis to the upward," clearly defining the coordinate system direction and providing spatial reference for data interpretation, thus facilitating accurate stress relief test analysis.

[0111] like Figure 12 to 14 The image shown is an example of data processing performed by the triaxial experimental data analysis module, stress direction plotting module, and stress polygon analysis module included in the toolset. Figure 15 The figure shown is a diagram of the calculation results from the stress relief geostress analysis module.

[0112] In some embodiments, the executable hydraulic fracturing method configured in the hydraulic fracturing module can be a currently known method or a method improved by the present invention.

[0113] In the classical theory of hydraulic fracturing stress testing, stress calculations still primarily follow the elastic model first described by M.K. Hubbert and D.W. Williams, based on the following three fundamental assumptions: ① the rock is linearly elastic and isotropic; ② the rock is intact, and the fracturing fluid is impermeable or low-permeable to the rock; ③ there is a principal stress direction parallel to the borehole axis. Under these theoretical and assumption premises, the mechanical model of hydraulic fracturing can be simplified to a plane stress problem, such as... Figure 16 As shown.

[0114] When principal stresses σ1 and σ2 act on an area containing a radius of... a On an infinitely large flat plate with a circular hole, according to elasticity analysis, the stress at any point M outside the hole is:

[0115] (1)

[0116] In equation (1), σ r The radial stress at point M, σ θ For tangential stress, τ rθ For shear stress, r Let M be the distance from point M to the center of the circular hole. Based on equation (1), the stress distribution at various locations around the hole can be obtained, and when r = a At that time, the stress state on the hole wall is obtained as follows:

[0117] (2)

[0118] From equation (2), it can be seen that the tangential stress distribution on the hole wall is similar to a cosine curve, so as follows:Figure 16 The tangential stress concentrations at points A and B on the hole wall shown, and at their symmetrical points (A′, B′), are as follows:

[0119] (3)

[0120] like σ 1> σ 2, then σ A < σ B Therefore, when the fluid pressure applied inside the circular hole... P When the stress exceeds the rock's in-situ tensile strength (overcoming the rock's tensile strength), tensile fracture will occur at the location of minimum tangential stress, i.e., point A and its symmetrical point A′, and the fracture will propagate in a direction perpendicular to the minimum principal stress. Fracture pressure P b It equals the stress concentration at the fracture point of the borehole wall plus the in-situ tensile strength of the rock. T Considering the pore pressure present in the rock P p (Also often recorded as) P 0), rupture pressure P b Export as:

[0121] (4)

[0122] In vertical borehole stress measurement, the maximum and minimum horizontal principal stresses are often written as: S H and S h ,Right now σ 1= S H , σ 2= S h Therefore P b (4) can be rewritten as:

[0123] (5)

[0124] After the borehole wall fractures, if fluid injection and pressurization continue, the fracture will continue to extend deeper into the rock mass. If fluid injection and pressurization are stopped, and the fracturing circuit is kept closed, the fracture will quickly stop extending and, under the influence of the in-situ stress field, rapidly tend to close. The fluid pressure at which the fracture is critically closed is usually called the closure pressure. P s And as a good estimate of the minimum horizontal principal stress perpendicular to the crack surface, that is:

[0125] (6)

[0126] Therefore S H It can be exported as:

[0127] (7)

[0128] Rupture pressure of the first cycle of the hydrostatic fracturing test P b The pressure at which the crack reopens during subsequent cycles, i.e., the retension pressure. P r The difference should be equal to the tensile strength of the rock, which can be used to calculate the maximum horizontal principal stress. Furthermore, the tensile strength value determined based on field fracturing data avoids many uncertainties present in laboratory measurements. Therefore, it can be derived that:

[0129] (8)

[0130] (9)

[0131] Vertical stress S v The weight of the overlying rock at the measured section location can be estimated as follows:

[0132] (10)

[0133] In the formula ρ For rock density, g It is the acceleration due to gravity. h The depth of the overlying rock.

[0134] The above is the basic theory for calculating principal stress using the conventional hydraulic fracturing stress measurement method.

[0135] Based on the above fundamental theory, in some embodiments, the hydraulic fracturing module is configured to determine the fracture re-tensioning pressure.

[0136] Re-tension pressure typically refers to the pressure at which, during hydraulic fracturing stress measurement, a near-parallel (approximately 180°) symmetrical fracture occurs in the rock mass of the test section, followed by constant flow pressurization. The pressure at which the pressure-time curve deflects from a straight line due to the entry of fracturing fluid into the fracture is the re-tension pressure. Re-tension pressure is a crucial parameter for calculating the maximum horizontal principal stress. Currently, methods for obtaining this parameter include: ① the tangent method based on the pressure-time curve, ② the tangent method based on the pressure-cumulative injection volume curve, and ③ the translation method. These methods are all based on pressure data. The implementation of these three methods on the geostress analysis platform is described below:

[0137] (1) Tangent method based on pressure-time curve

[0138] Plot the pressure-time curve for the retensioning re-intensification stage, tangent to the curve near the starting point with a straight line. The pressure value corresponding to the point where the line deviates from the curve is taken as the retensioning pressure. Figure 17 .

[0139] (2) Tangent method based on pressure-cumulative injection volume curve

[0140] Plot the pressure-cumulative injection volume curve for the re-tensioning re-pressurization stage. Draw a straight line tangent to the curve near the starting point. When the straight line deviates from the curve, the pressure value corresponding to the deviation point is taken as the re-tensioning pressure.

[0141] (3) Translation method

[0142] The pressure curve of the re-tensioning pressurization stage is shifted to the position of the fracturing stage where no fracturing occurred, to create a comparison. When the pressure curve of the re-tensioning stage deviates from the pressure curve of the fracturing stage, the pressure value corresponding to the deviation point is taken as the re-tensioning pressure. Figure 18 .

[0143] The above are three methods for determining the re-tension pressure. It can be seen that, under a sufficiently large window scale, the tangent method based on the pressure-time curve, the tangent method based on the pressure-cumulative injection volume curve, and the translation method show obvious deviations of the curve from the straight line. At the same time, the results of the three methods are also quite similar.

[0144] In some embodiments, the hydraulic fracturing module is configured to determine the fracturing closure pressure.

[0145] Fracture closure pressure is used to estimate the minimum horizontal principal stress (minimum principal stress) of the formation. The minimum horizontal principal stress is directly related to the calculation of the maximum horizontal principal stress. Therefore, accurately and objectively picking the closure pressure from the experimental curve is crucial for improving the reliability of the test results. Currently, researchers both domestically and internationally engaged in hydraulic fracturing stress measurement have proposed various data analysis methods for picking corresponding pressure points under different conditions.

[0146] (1) Single tangent method

[0147] This method, derived from the inflection point method and successfully applied by JM Gronseth et al. in high-modulus crystalline rocks, is a simple graphical technique. JM Gronseth et al.'s research indicates that: ① In low-flow fracturing experiments (<50 L / min), the pressure should be shut off... P s This is equal to the inflection point of the pressure-time curve after the pump is stopped. Therefore, it is proposed to draw a straight line tangent to the pressure-time curve from the pump shutdown point. When this line deviates from the curve, the stress value at the deviation point is...P s ② All in multiple pressurization cycles P s The minimum value is generally closer to the minimum principal stress; ③ Indoor fracturing test results show that when the horizontal stress ratio is greater than 2, the value determined by this method is... P s It may be significantly higher than the minimum principal stress.

[0148] In practice, the single tangent method typically employs two approaches: manual line drawing and interpretation, or computer-based interpretation. Relatively speaking, the former is more adaptable to curves with different morphological characteristics, but visual interpretation is heavily influenced by the time scale and is highly arbitrary; while the latter primarily overcomes the arbitrariness of manual visual interpretation and improves data analysis efficiency. However, regardless of whether manual line drawing or computer-based interpretation is used, the selection of the near-linear pressure drop segment and the confirmation of deviation points still involve a degree of subjectivity. For example... Figure 19 Figure b shows that when the time window is narrowed to approximately 20–50 seconds, the pressure value obtained by the tangent method is higher than that obtained by the tangent method. Figure 19 The value of 'a' is too high. Due to the friction in the water circuit, it drops to this value very quickly after the pump is turned off. This value is generally recorded as 'a'. ISIP or P si .

[0149] In summary, although this method is relatively simple to apply, it is heavily affected by the time window. Applying this method to different runs of the same test curve, or having different data processing personnel select the same run, often results in inconsistent results. In fact, the pressure points determined by this method lack clear and reasonable physical meaning and are difficult to apply to test curves with different shapes.

[0150] (2) Muskat method

[0151] Based on the fluid flow characteristics of boreholes and porous rock masses, M. Muskat proposed an exponential pressure decay model caused by radial flow to analyze and predict bottom hole pressure changes in oil wells. This model is also known as the exponential pressure decay method or nonlinear regression method. This method assumes that after a fracture closes, no fluid leaks through the fracture, and fluid only seeps into the rock mass through the borehole wall. Therefore, the stress decay within the borehole section should satisfy the following formula (sometimes expressed as its natural logarithm):

[0152] (11)

[0153] In the formula: P It is the pressure within the test section. d 1 (<0) and d 2 is an undetermined parameter characterizing pressure decay. P a It is the asymptotic pressure within the test section.t It is time. t r It is the time when pure radial flow begins (corresponding to the complete closure of the crack).

[0154] RL Aamodt et al. and MY Lee et al. applied this method to the identification of shut-in pressure during the shut-in period of HF test curves and summarized the analysis process. The analysis process of this method generally involves selecting pressure-time data for the pressure drop interval after pump shut-in based on a computer program. As the left boundary of the time interval is pushed forward, nonlinear fitting of the interval data is performed using formula (11), and the fitting residuals are recorded. Finally, the optimal solution is obtained when the residual is minimized or stabilized at a specified threshold, corresponding to the optimal fitting parameters. Figure 20 MY Lee et al. pointed out: ① P sr Corresponding to the complete closure of the crack ( t r At the moment when pure radial flow begins, the pressure is the maximum value among the data participating in the exponential fitting; ② The pressure value corresponding to the pump shut-off time is obtained by extrapolating the fitted curve back to the pressure value corresponding to the pump shut-off time. P s This value refers to the pressure required to maintain the same radial flow under the assumption that the fracture closes immediately after the pump is shut off; it can be used as an approximation of the minimum principal stress. LS Cheung et al. applied the Maskat method to process indoor fracturing experimental data and found that the obtained... P s It is closer to the minimum horizontal principal stress of the actual load, while P sr It is usually on the lower side.

[0155] Due to factors such as the surface roughness of the fracture wall, fractures often cannot completely close, leaving residual fracture width and conductivity. Therefore, in many cases, the assumption that fluid only seeps into the rock mass through the pore wall after fracture closure cannot be satisfied, especially for low-permeability formations. Simultaneously, this method uses the pressure value corresponding to the pump shut-off time, derived from the fitted curve, as... P s This value lacks a clear physical meaning, and the explanation given by MY Lee et al. is somewhat vague and far-fetched. Furthermore, this method is affected to some extent by the time window.

[0156] (3)d P / d T Law

[0157] Also known as the bilinear pressure decay method, MY Lee et al. pointed out that the functional expression of pressure decay before crack closure is complex and unknown. As an approximation, it can be assumed that this part of the pressure decay before crack closure is also represented by an exponential function. That is, the pressure decay after pump shutdown can be composed of two exponential function curves, with a dividing point between them. The pressure value corresponding to this point is... P s See equation (12):

[0158] (12)

[0159] In the formula: t s This corresponds to the time it takes for the crack to close. d 3 (<0) and d 4 is t s Previously undetermined parameters characterizing pressure decay; d 5 (<0) and d 6 is t s The undetermined parameters characterizing pressure decay are then identified. P a2 and P a3 It is an unknown asymptotic pressure. By differentiating equation (12) with respect to time, we can obtain d. P / d T and P The bilinear relationship between them is:

[0160] (13)

[0161] The general analysis process of this method is to calculate the difference d based on the pressure-time data of the pressure drop range after the pump shut-off point. P and d T Then -d is obtained. P / d T , draw -d P / d T and P The relationship curve or scatter plot is used to recursively deduce the pressure threshold from small to large. Each time, the two sets of data around the threshold are linearly regressed, and the total residual is recorded. The minimum total residual across all cases is considered the corresponding optimal solution, and the pressure value at the intersection of the corresponding lines is considered the optimal solution. P s ,See Figure 21 .

[0162] In practice, the analysis process has the following characteristics: ① Appropriate smoothing or resampling of the original data can effectively reduce the impact of data noise, especially for data acquired from well sites; ② For data with a vertical axis of -d... P / dT ① The slopes of the two fitted lines should be positive, and the slope of the fitted line on the side with higher pressure value should be greater than the slope of the other fitted line; ② Least square regression takes the minimum sum of squared errors as the objective function, but variance is an unrobust statistic. When the error does not follow a normal distribution, the regression result is affected by outliers to some extent. For pressure datasets with different curve characteristics, robust regression algorithms (such as the least median method) can be used to effectively remove outliers; ③ It is affected by the time window to some extent; ④ Due to the existence of the above problems, and the fact that the "bilinear" analysis method itself is based on "approximation" and directly established, the physical meaning or the corresponding pressure fracture state indicated by the pressure value obtained by this method is unclear in terms of the crack closure process.

[0163] (4)d T / d P Law

[0164] Based on the theory of linear elastic fracture mechanics and the conservation of mass of the fracturing fluid, K. Hayashi et al. derived a differential equation for controlling the pressure drop after pump shutdown and conducted a detailed study on the closure of hydraulic fractures. They pointed out that after pump shutdown, the process from "pump shutdown point → end of instantaneous fracture propagation" is generally completed instantaneously or within a short time window. The closure process of hydraulic fractures mainly involves three stages: the first stage is from the end of instantaneous fracture propagation to the closure of the fracture tip; the second stage is from the closure of the fracture tip to the complete closure of the fracture; and the third stage is from the closure of the entire fracture to the end of the experiment. Based on theoretical deduction and field and laboratory tests, they also pointed out that the reciprocal of the pressure drop rate in each of the three stages is related to the fluid pressure. P The relationship is approximately linear.

[0165] The general analysis process of this method is to calculate the difference d based on the pressure-time data of the pressure drop range after the pump shut-off point. P and d T , and then obtain d T / d P , draw d T / d P and P The relationship curve or scatter plot is used, and the two pressure cutoff points are recursively calculated from small to large. In each case, the three sets of data around the cutoff point are linearly fitted and the total residual is recorded. The minimum value of the total residual in all cases is considered the corresponding optimal solution. P s Determined by the pressure value at the intersection of the first and second stage straight lines, see Figure 22 In practice, this method has the same characteristics as d. P / d T Similar characteristics to the law. But compared to d P / d T Legally speaking, d T / dP The physical meaning of the value is relatively clear, namely the fluid pressure at which the tip of the hydraulic fracture begins to close.

[0166] In some embodiments, considering that the above-mentioned hydraulic fracturing methods all have certain defects, a novel method for calculating the closure pressure is integrated into the hydraulic fracturing module, namely, calculating the closure pressure based on the independently proposed Total System Stiffness (TSS) method.

[0167] This embodiment provides a simplified description of the interactions occurring in the wellbore / fracture / formation system during HF testing. First, during the experiment, the fluid pressure in the test section... P Changes and testing system and fluid volume present in the crack V The change is directly related to, rather than, time. t Therefore, the pressure decay rate d P / d t The following decomposition can be performed based on the chain rule:

[0168] (14)

[0169] In the formula, V That is, the total fluid volume existing within the testing system and the crack; d P / d V Defined as the overall system stiffness S t ;d V / d t That is, the instantaneous flow rate of the fluid; V I and V L These represent the cumulative injected fluid volume and the cumulative leaked fluid volume of the measured section, respectively. Q I (= V I / t The instantaneous injection flow rate can be considered a constant during the experiment. Q L Defined as instantaneous leakage flow, since under normal circumstances Q I >> Q L Therefore, it is omitted during the injection phase.

[0170] Equation (14) shows that the evolution of the pressure-time curve of the experimental section is determined by the overall system stiffness at different times. S t and the instantaneous flow rate d of the fluid V / d t Joint control; for the injection phase, d V / d tIt can be approximated as equal to Q I , is a constant; for the pressure decay stage, d V / d t Will be entirely by Q L The decision, which is influenced by pressure P d decreases monotonically and continues to decrease; therefore, d V / d t The inability to effectively indicate the opening and closing state of cracks is the main reason for the ambiguity of the aforementioned traditional methods. Therefore, it is necessary to focus on analyzing the first critical component coupled with it. S t Theoretically, the overall system stiffness S t It can also be represented by superposition using the flexibility form as follows:

[0171] (15)

[0172] In the formula, C t The overall system flexibility (stiffness and flexibility are reciprocals of each other); A f and V f These represent the total area and volume of the pressure crack, respectively. V s The volume of the fracturing section and drill pipe can be calculated based on the actual working conditions. S f The crack stiffness is controlled by the crack size, the rock's elastic modulus, and Poisson's ratio, and can also be determined by d. V f / d P Sure; S s To test the system stiffness, it can be done by... V s c w The reciprocal of the equation can also be determined by the slope of the pressure and the cumulative injection volume during the second pressurization stage of fracturing. c w The fluid's compressibility coefficient; w fm This represents the average fracture width. It should be noted that the above formula does not consider the deformation of drill pipes and packers, as these are negligible compared to the flexibility of water. Furthermore, it does not consider the compressibility of the fluid within the fracture, because under normal circumstances… V f c w << V s cw .

[0173] Crack closure is a gradual process, not an instantaneous event. As shown in Equation 2, with the decrease in fluid pressure, the crack size will inevitably decrease. S f It will inevitably continue to increase, leading to S t Increase; when the crack begins to close at the tip, the contact between the crack walls will lead to dw fm It began to decrease significantly, thus leading to S t It begins to increase rapidly; once the cracks tend to close completely, S f It will tend towards infinity, that is dw fm Approaching zero S t Will be entirely by V s c w The dominant value is approximately stable. Based on the above analysis, it can be concluded that... S t The evolution of the fracture is closely related to the closure process of the hydraulic fracture, and there is a direct correspondence between them. Figure 23 The idealized relationship between the overall system stiffness and the measured segment pressure during the pressure decay stage is shown. The slope of the overall system stiffness curve changes with the crack closure state. After the pump is shut down, the two inflection points on the curve correspond to the closure of the crack tip and complete closure, respectively. It should be noted that the inflection point of complete crack closure does not mean that the crack width is ideally equal to zero; its residual crack width is supported by the roughness on the relative crack wall.

[0174] To obtain information on the change in overall system stiffness from the pressure-time curve during the pressure decay phase, it is first necessary to establish and derive the constitutive relation characterizing the volume change of the system, that is, to understand the changes at different times. P and V The course of change, among which P The pressure can be obtained from surface or downhole pressure gauges during the experiment, so the key is to analyze the volume. V ,that is V L ,because V s and V I This is known from actual testing. For an objective and simple derivation... V L With Δ t The relationship between the pump shut-off moment and the depressurization moment is based on the following assumptions:

[0175] The formation rock mass is approximately isotropic, containing only one slightly compressible fluid, and the properties of the injected fluid are similar to those of the rock strata fluid; the pore pressure of the measured rock mass... P p Fluid viscosity μ Porosity Compression coefficient c t and penetration rate k All with P Irrelevant; the rock strata have low permeability, and the pore elasticity effect caused by fluid leakage is negligible.

[0176] Fluid pressure within the fracturing section and fracture P They are equal, without considering the pressure gradient problem.

[0177] Fluid leakage is considered only for flow perpendicular to the rock wall or crack surface; seepage in the parallel direction is ignored.

[0178] During the pressure decay phase, the surface area of ​​the crack remains constant until the crack closes. This means that even after the crack closes, it still exhibits hydraulic conductivity, and its residual crack width is supported by the roughness of the relative crack walls.

[0179] The cumulative leakage volume is calculated based on the above assumptions. V L With time interval Δ t The relationship is derived as follows. First, the total seepage area... A It can be approximated by the surface area of ​​the fracture and the lateral area of ​​the fracturing section, that is:

[0180] (16)

[0181] In the formula, h t This refers to the length of the fracturing section. d The diameter of the borehole (e.g.) Figure 23 As assumed, the total seepage area... A This can be considered a constant during the pressure drop test. Therefore, the instantaneous fluid leakage flow rate occurs through the fracture surface area and the side area of ​​the fracturing section. Q L Based on the Carter leakage model, it can be derived as follows:

[0182] (17)

[0183] in, t The duration of fluid infiltration. The square root of the molecule contains some intrinsic parameters related to the formation rock mass, which are assumed to be represented as a constant Ψ. P pThe pore pressure of the rock mass being measured can be approximated as a constant. In HF tests with small injection volumes, the pore pressure disturbance caused by leakage is weak and usually negligible, especially for low-permeability rocks. By applying equation (17) over the pressure decay time Δ... t Integrating the result (from pump shutdown to pressure relief) yields the result of pump shutdown. t The cumulative fluid leakage volume after (=0) V L :

[0184] (18)

[0185] Pressure data in equations (17) and (18) P ( t This information can be obtained through a pressure gauge. During the pressure decay phase, as... P ( t The pressure difference decreases. P ( t )- P p It will also decrease over time. However, it cannot be described using a simple and precise mathematical formula. P ( t To address the cumulative leakage in equation (19) V L With pressure difference [ P ( t )- P p The relationship between pressure drop time and time Δ is necessary. t Divide into n equal intervals τ ,Right now:

[0186] (19)

[0187] Therefore, given the known measured pressure data P ( t ) and time data Δ t Under the given conditions, equation (18) can be written in the following discrete form using the summation formula:

[0188] (20)

[0189] Since the data acquisition frequency is typically kept constant during HF testing, τ It is considered a constant. The integer n represents the total number of pressure points collected during the pressure decay period, which is a known value after HF testing. The integer i ranges from 1 to n, representing each small interval. τ The index number. Each time interval τ The corresponding pressure can be expressed as P(i). It should be noted that, due to the very small time interval... τ The internal pressure drop is very small, therefore it can... P (i) is considered as the pressure value at the upper left boundary of each subinterval. C The function is defined as the fluid leakage volume. V L They are in a linear proportional relationship because A Ψ and τ It is considered a constant. Therefore, C The function describes the pressure decay phase. V L The relative trend of change, despite their different dimensions. C The function expression is:

[0190] (twenty one)

[0191] During the pressure decay phase, fluid injection has ceased, and the testing system will remain sealed. As fluid continues to leak into the formation rock mass, the fluid pressure will gradually decrease, and under the influence of geostress, the fracture walls will gradually close and approach the remaining fracture width. During this stage, P or V The change is entirely due to the fluid leakage volume V L This causes, therefore, the overall system stiffness S t The changes can be directly derived as:

[0192] (twenty two)

[0193] in, S t ′ is defined as the dimensionless overall system stiffness. With P The reduction, P and P p The difference between them gradually decreases, leading to Q L This decreases, meaning the rate of fluid loss or change in crack volume decreases. When the crack is nearly completely closed, the rate of change in crack volume approaches zero. After this point, the water volume in the test system... V s Will dominate the overall system stiffness S t crack stiffness S f Approaching infinity ( Adw fm (Tend to zero). Therefore... S tThe curve will tend to be horizontal, which is consistent with the analysis in the aforementioned equation (15). This also means that after the rate of change of crack volume approaches zero, the effect of fluid leakage on the overall system stiffness can be ignored, which is similar to the fact that the compressibility of the fluid in the crack was not considered in equation (15). In other words, the main factor affecting the change in the overall system stiffness is the crack closure state, i.e., the change in crack geometry, which is the crack stiffness. S f The change is due to the fluid itself, not the fluid that leaked.

[0194] In summary, during the pressure decay stage, the evolution trend of the total system stiffness (TSS) can be directly estimated using HF measured pressure-time data and equation (21), and further used to identify the crack closure process and determine the upper and lower limits of the closure pressure. It is expected that... S t 'and P Relationship curve (see) Figure 24 Two distinct inflection points will be observed, corresponding to crack tip closure (stiffness begins to increase significantly) and complete closure (stiffness tends to stabilize), respectively. It should be noted that... S t ′ and the actual stiffness value S t The stiffness curve exhibits a constant proportional relationship with the stiffness curve, and therefore can also be referred to as the reduced stiffness. Without affecting the evolution trend of the stiffness curve, it can be scaled using a certain coefficient or some standardization algorithms.

[0195] In some embodiments, the hydraulic fracturing module is further configured to automatically identify multiple key characteristic moments during the hydraulic fracturing experiment.

[0196] like Figure 25 As shown, the experiment typically involves multiple repeated runs. Each run includes three key moments: pump start-up, pump shutdown, and pressure relief. These three moments are the endpoints for calculating key characteristic pressure parameters, i.e., the endpoints of the time interval, and need to be clearly defined. Based on the data characteristics at pump start-up, pump shutdown, and pressure relief, the platform developed a characteristic slope threshold method to automatically identify the three characteristic moments in each run, thus directly determining the stress calculation interval. The slope threshold has an initial value, obtained empirically based on a large amount of measured data, which can satisfy most measured curves. For individual cases where identification is not possible, the slope value can be manually adjusted, thereby achieving characteristic moment identification for all runs, providing objectivity and convenience for the reliable calculation of geostress measurement results. Combined with... Figure 25 As can be seen, this embodiment successfully identified each iteration and allows for one-click switching.

[0197] In some embodiments, the three-dimensional hydraulic fracturing analysis module can perform stress measurement and calculation in the following manner:

[0198] For ease of calculation, we first establish a fixed geodetic coordinate system (0—XYZ), with the Z-axis pointing vertically upwards. The X-axis can be set to a direction as needed (generally, the X-axis points due south), and its azimuth angle is... β 0, using the actual borehole (numbered i, equal to 1, 2, 3...) coordinate system 0-X i Y i Z i For the active coordinate system, Z i The axis direction is the direction of the borehole axis, with the direction pointing towards the borehole opening being positive. (Axis X) i The horizontal direction is indicated by looking inwards from the orifice; the direction pointing to the right is positive. The Y-axis... i Determined using a right-handed coordinate system.

[0199] Let the borehole inclination angle be... azimuth angle is , For from X i Rotate the axis counterclockwise to the angle of the pressure crack, and let the stress components represented by the moving coordinate system be... , and These are related to the major and minor secondary principal stresses within the borehole cross-section obtained from actual measurements of borehole i. The following relationship exists:

[0200] (twenty three)

[0201] Through vector cosine coordinate transformation, their relationship with stress components in the geodetic coordinate system can be obtained as follows:

[0202] (twenty four)

[0203] Therefore, a single hydraulic fracturing borehole yields three equations, and three boreholes result in nine equations. Thus, the original rock stress components (i.e., the stress component matrix X) can be solved from this overdetermined system of nine equations containing six independent variables. According to the least squares method, both overdetermined and underdetermined equations can generally be solved, but the more independent equations there are, the more reliable the results. Therefore, the number of boreholes n involved in the calculation should be no less than two, typically three approximately orthogonal boreholes. Solving for the three-dimensional geostress state at a point mainly involves solving for the second-order stress component matrix X (a symmetric matrix with six independent components) at that point.

[0204] (25)

[0205] According to formula (24), take n=3, and set the stress component coefficient matrix as A. 3n×6 =A 9×6 Let matrix B 9×1 for:

[0206] (26)

[0207] The above system of equations can then be written as AX = B. The best approximate solution to this equation, i.e., the optimal solution for the stress components in the real domain, is obtained using the least squares method. Based on the stress component matrix X, the eigenvalues ​​and corresponding eigenvectors are obtained. The eigenvalues, in order of magnitude, represent the principal stresses; positive and negative values ​​represent tension and compression states. The spatial orientation of the principal stresses can be obtained from their corresponding normalized eigenvectors. Let the eigenvectors of the X, Y, and Z axes in the fixed coordinate system correspond to the symbols lmn, i, and 3 respectively. The principal stresses are numbered i as 1, 2, and 3, and the inclination angles of each principal stress are... and azimuth It can be calculated using the following formula:

[0208] (27)

[0209] Azimuth is defined as 0° with true north as the reference, and clockwise is positive (0°~360°). Dip is positive with upward inclination (0°~90°) and negative with downward inclination (-90°~0°). Azimuth and dip, which describe the orientation of principal stresses, appear in pairs. If the azimuth is increased by 180°, the dip must be the opposite number, and vice versa.

[0210] In some embodiments, the inelastic strain recovery method calculation module integrates the ASR geostress testing method to realize inelastic strain recovery method geostress measurement and calculation.

[0211] The testing procedure for the ASR geostress testing method is as follows: Figure 26 The main method for core orientation is to compare the imaging logging of the borehole wall with the core surface to determine the geographical orientation of the marker lines on the core (in cases where this is not possible, paleomagnetic methods are also used for core orientation). After unloading the core, the inelastic normal strain is measured in at least six independent directions (generally nine directions are measured). The inelastic strain components and principal strains are then calculated. Since the direction of the principal strain is the same as the direction of the in-situ stress, the direction of the in-situ stress can be determined simply by measuring the principal strain of the oriented core. To calculate the magnitude of the in-situ stress, in addition to obtaining the inelastic strain tensor, an experiment on the inelastic strain recovery compliance of the rock is required. Based on determining the corresponding inelastic strain recovery compliance of the rock, the magnitude of the in-situ stress can be determined relatively accurately.

[0212] Relationship between core strain observations and strain components in the core coordinate system

[0213] Let the core coordinate system be ox′ y′ z′, with the z′ axis parallel to the major axis of the core. The strain observation value b and the strain components in the core coordinate system... , , , , , The relationship is as follows:

[0214] (28)

[0215] In the formula: These are the strain components in the core coordinate system; To recover the observed values ​​of inelastic (hysteretic) strain from the rock core. The strain observation value of axis a1 is the average value of the two strain gauges corresponding to axis a1. This represents the strain observation value for axis a2, i.e., the average value of the two strain gauges corresponding to axis a2; and so on, until... . It is a coefficient matrix. The expansion is as follows:

[0216] (29)

[0217] , , (i=1…9) are the direction cosines of axes a1 to a9 relative to the ox′, y′, and z′ axes. The specific values ​​of the direction cosines are shown in Table 1.

[0218] Table 1 Direction Cosines

[0219]

[0220] Substituting the direction cosine values ​​from Table 1 into equation (29), we get:

[0221] (30)

[0222] Least squares solution for strain components.

[0223] In formula (28), the unknown n = 6, while the number of equations m = 9. Since the number of equations m is greater than the unknown n, the least squares method can be used to solve the problem and obtain the most reliable answer. According to the principle of the least squares method, the following system of equations can be solved to obtain the least squares solution.

[0224] (31)

[0225] The solution to the above equation is as follows:

[0226] (32)

[0227] Coordinate transformation of strain

[0228] Let the geographic coordinate system be o-xyz. The x-axis points north, the y-axis points east, and the z-axis points vertically downward. Because the core coordinate system is arbitrarily set, the drilling (core) is sometimes tilted, and the ox′ axis of the core coordinate system is not necessarily northward, the core coordinate system and the geographic coordinate system are usually not coincident. To calculate the direction, dip angle, and magnitude of the principal strains (principal stresses), it is necessary to transform the strain components in the core coordinate system to the geographic coordinate system. The expression for coordinate transformation is as follows:

[0229] (33)

[0230] in Table 2 shows the direction cosines between the core coordinate axes and the geographic coordinate axes. As mentioned earlier, Let be the strain tensor in the core coordinate system.

[0231] This is the strain tensor in the geographic coordinate system.

[0232] Table 2. Direction cosines of core coordinate axes and geographic coordinate axes

[0233]

[0234] Knowing the dip direction, dip angle, and azimuth of the core coordinate axis ox′, the direction cosine can be easily calculated. From the direction cosine, the strain tensor in the geographic coordinate system can be obtained from equation (33). .

[0235] Calculation of the magnitude and direction of principal strain.

[0236] The strain state at a point can be represented by three principal strains. The principal strains can be obtained by solving the following system of equations from the strain components:

[0237] (34)

[0238] The above system of equations is a homogeneous linear system of equations. A necessary and sufficient condition for the system to have non-zero solutions is that the determinant of the coefficient row is zero. That is:

[0239] (35)

[0240] Expanding the determinant yields a cubic equation in one variable. Solving this equation gives three roots. They are the three main strains , , Substituting each of the three principal strains back into equation (34), the direction cosines of the three principal strains can be obtained. , , (i=1,2,3), and .

[0241] The above solution is actually the problem of finding the eigenvalues ​​and eigenvectors of the strain component matrix. The principal strain is the eigenvector, and the direction cosine of the principal strain is the eigenvector. The orientation and dip angle of the principal strain can be obtained from the direction cosine.

[0242] Main strain Azimuth angle of (i=1,2,3) ,like ,but Main strain Inclination angle of (i=1,2,3) , In a homogeneous and isotropic viscoelastic medium, the orientation of the principal strain is the same as the orientation of the principal stress. Therefore, knowing the orientation of the principal strain tells us the orientation of the principal stress.

[0243] Calculation of principal stress magnitude.

[0244] Calculation of principal stresses from inelastic strain The expression for (i=1,2,3) is as follows:

[0245] (36)

[0246] In the formula (i=1,2,3) represents inelastic deviatoric strain. For inelastic strain, For partial inelastic strain compliance, For volumetric inelastic strain compliance, This refers to pore pressure.

[0247] As can be seen from the above formula, we only need to find and The three-dimensional geostress can then be calculated based on the inelastic strain and pore pressure.

[0248] and This can be obtained experimentally, but the experiment is quite complex. Existing literature indicates that it can be approximated as...

[0249] (37)

[0250] Therefore, the vertical stress can be expressed by the following formula:

[0251] (38)

[0252] In the formula, l p ,m p , n pThis is the direction cosine of the vertical stress relative to the three principal strain axes. The vertical stress can also be calculated using gravity.

[0253] (39)

[0254] If the depth to be measured is known h The average density and gravitational acceleration from the surface to this depth g ,but It can be derived from equation (39), and can be obtained from equation (38). Then, by equation (37), we can obtain Then the principal stresses are obtained from equation (36). (i=1,2,3).

[0255] The principal strains and principal stresses mentioned above have been calculated using a geostress analysis platform.

[0256] In some embodiments, determining the rock compliance ratio is crucial to the final result, considering the entire process of obtaining three-dimensional geostress through inelastic strain analysis (ASR). However, obtaining this ratio through laboratory experiments is quite cumbersome. The inelastic strain recovery method calculation module in the platform integrates a novel inelastic strain recovery method, which realizes the determination of the rock compliance ratio based on the minimum horizontal principal stress obtained from hydraulic fracturing, combined with inelastic strain data. This ratio is then used for inelastic strain analysis to obtain three-dimensional geostress information, significantly improving the reliability and practicality of the method in three-dimensional geostress test results.

[0257] Specifically as follows:

[0258] The ASR method is a three-dimensional geostress measurement method based on directional rock cores, developed in recent years. Compared with other core-based geostress measurement methods, its theoretical foundation is more complete. Measurements performed at the drilling site can maintain the near-in-situ state of the rock core and have advantages such as not being limited by measurement depth or testing environment. Under the assumption that the rock is homogeneous, isotropic, and viscoelastic, the ASR method measures at least six independent directions of inelastically recoverable strain. The calculated principal strain directions are the principal stress directions (geographic orientation of the test core baseline is required; otherwise, the principal stress direction information is relative). The stress components and inelastically recoverable strain... ε a The relationship between them is as shown in equation (40):

[0259] (40)

[0260] In the formula: l , m , n The direction cosine of the strain axis; σ x, σ y , σ z , τ xy , τ yz ,τ zx These are stress components; σ m The average stress; P 0 represents pore pressure; α T Δ is the linear thermal expansion coefficient; T (t) represents the temperature change during the measurement period; Jas (t) represents the inelastic strain recovery compliance in shear mode; Jav (t) represents the volumetric mode inelastic strain recovery compliance. Typically, methods such as constant-temperature water baths are used during the experiment to maintain constant pore pressure and temperature in the rock core.

[0261] The magnitude of the three-dimensional principal stress can be expressed in terms of deviatoric strain and volumetric strain:

[0262] (41)

[0263] In the formula: σ i Principal stress, e i (t) represents the inelastic deviatoric strain. e m (t) represents the inelastic strain; i = 1, 2, 3. The inelastic strain is usually restored to its compliance ratio (t). Jas (t) / Jav (t) can be written as a constant. k :

[0264] (42)

[0265] in, Jav (t) can be directly determined by the vertical stress at the measuring point, and the relationship is as follows:

[0266] (43)

[0267] In the formula, l p , m p , n p This is the direction cosine of the vertical stress relative to the three principal strain axes. Simultaneously, the vertical stress can be calculated based on the overlying gravity. h To test the burial depth of the rock core samples, ρThe average density of rock from the surface to this depth. g Let gravitational acceleration be the acceleration due to gravity. The relationship between the minimum horizontal principal stress and the stress components is expressed as follows:

[0268] (44)

[0269] Currently, constant k The main approach is to directly assume a constant value of 2 or 1.56 based on previous experimental results to calculate the ground stress value. It can be seen that, based on equation (43), the stress value can be easily calculated. Jav Substituting (t) into equation (40) yields the result. Jas (t); further using equations (40), (41), and (44), the stress components, principal stresses, and directions at the depth of the measuring point can be obtained. The above are the main calculation formulas for obtaining three-dimensional geostress information using the ASR method. For inelastic recoverable strain, using a precision recorder and a three-wire precision strain gauge with temperature compensation, the measurement accuracy of the entire system reaches ±1 micro-strain, which can meet the measurement requirements of inelastic recoverable strain after core unloading; while for the inelastic strain recovery compliance ratio of rock k Direct assumptions will obviously introduce random errors into the in-situ stress analysis results, because with changes in lithology, rocks of different strengths... k The values ​​will vary to some extent, and due to differences between indoor experimental conditions and the in-situ environment, the values ​​determined by indoor experiments will also vary. k The value also has a certain degree of randomness.

[0270] To reliably obtain the three-dimensional geostress state of the formation, it is necessary to combine the technical advantages of hydraulic fracturing and ASR methods, namely, based on the minimum horizontal principal stress determined by the HF method. σ h To calibrate the inelastic strain recovery compliance ratio k This allows for the acquisition of three-dimensional geostress information from ASR (Automatic Stress Reduction) method test results, thereby improving the reliability of geostress measurement results in soft rock formations. However, due to... σ h and k The relationship between them is implicit and cannot be derived by formula. Therefore, this paper proposes a search method to determine the relationship. k The values ​​are as follows:

[0271] ① Determination of minimum horizontal principal stress based on HF method σ h And ASR testing was carried out using in-situ rock cores;

[0272] ② Order k =0, obtained by calculating using ASR test data. σ h The results were compared with those determined by the HF method. σh If the comparison is not accurate, then increase the value. k The value is recalculated until the value obtained by the ASR method is reached. σ h Determined by HF method σ h They are equal. Theoretically, k The smaller the step size for increasing the value, the better, such as 0.01 or 0.05.

[0273] ③ Using the calibrated k The values ​​are then re-involved in the ASR method calculation to obtain the stress components, principal stresses, and their directions at the depth of the measuring point. It should be noted that this is not directly related to the overall calculation and analysis process. σ h The direction of the core baseline is not involved, and they do not affect the magnitude of the geostress calculation results.

[0274] like Figure 26 According to the determined Jas (t) / Jav (t)(compliance ratio, k), combined with the relationship equation (Equation 43) that the vertical stress equals the weight of the overlying strata, the corresponding values ​​are calculated. Jav (t) and Jas (t), and then the maximum (t) is calculated based on the inelastic strain recovery strain data of the salt rock. σ 1) Middle ( σ 2) Minimum principal stress ( σ 3) Maximum ( σ H ), minimum ( σ h Horizontal principal stress and vertical stress σ v The values ​​are as follows: vertical stress is calculated based on the average density of the overlying rock strata, and the burial depth is taken as the average value of the measurement depth range.

[0275] The above embodiments are only used to illustrate the present invention and are not intended to limit the present invention. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, all equivalent technical solutions also fall within the scope of this application. The patent protection scope of the present invention should be defined by the claims.

Claims

1. A geostress analysis platform, characterized in that, include: The geostress database module is configured to centrally store, query, and update various geostress test data. The data preprocessing module is configured to perform data cleaning, format conversion, and outlier standardization on various types of geostress test data stored in the geostress database module to obtain preprocessed data. The calculation and analysis module integrates multiple geostress analysis methods to generate analysis results, including hydraulic fracturing, three-dimensional hydraulic fracturing, inelastic strain recovery, and stress relief methods, and supports a combination of automatic calculation and manual parameter adjustment. The plotting and statistics module is configured to generate stress distribution diagrams, stress ratio distribution diagrams, scatter plots of horizontal principal stress directions, and rose diagrams of horizontal principal stress directions based on the analysis results of the calculation and analysis module. The report export module is configured to output the analysis results of the calculation and analysis module as a structured document report; The toolset module includes a file renaming / data reorganization tool, a crack imprint simulation tool, a stress polygon analysis tool, and a four-component piezomagnetic geostress data analysis tool, which are used to enable diverse processing and analysis of various geostress test data. The inelastic strain recovery method calculation module is configured as follows: Obtain ASR test data for the minimum horizontal principal stress and different k values ​​determined by the HF method; wherein, the k value is the inelastic strain recovery compliance ratio. The minimum horizontal principal stress is calculated based on the ASR test data when k=0. The minimum horizontal principal stress is compared with the minimum horizontal principal stress measured by the HF method. If the difference between the two is greater than a set threshold, the value of k is increased by a set step size, and the minimum horizontal principal stress is recalculated until the difference between the minimum horizontal principal stress and the minimum horizontal principal stress measured by the HF method is at the set threshold, and the value of k is determined. Based on the determined value of k, and combined with the equation relating vertical stress to the weight of the overlying strata, the corresponding volumetric mode inelastic strain recovery compliance is calculated. Jav (t) and shear mode inelastic strain recovery compliance Jas (t), and the values ​​of the maximum principal stress, intermediate principal stress, minimum principal stress, maximum horizontal principal stress, minimum horizontal principal stress and vertical stress are calculated based on the inelastic strain recovery strain data of the salt rock.

2. The geostress analysis platform according to claim 1, characterized in that, The calculation and analysis module includes a hydraulic fracturing module, a three-dimensional hydraulic fracturing module, an inelastic strain recovery method calculation module, and a stress relief calculation module. The hydraulic fracturing module, the three-dimensional hydraulic fracturing module, the inelastic strain recovery method calculation module, and the stress relief calculation module are used to execute the hydraulic fracturing method, the three-dimensional hydraulic fracturing method, the inelastic strain recovery method, and the stress relief method, respectively.

3. The geostress analysis platform according to claim 2, characterized in that, The hydraulic fracturing module is configured as follows: The evolution trend of the overall system stiffness is used to identify the crack closure process and determine the upper and lower limits of the closure pressure; wherein, the evolution trend of the overall system stiffness is estimated using measured pressure-time data and the following formula: ； In the formula, S t Let P be the total stiffness of the system and P be the fluid pressure in the measuring section. t Let P(i) and P(i-1) be the time intervals, respectively, where P(i) and P(i-1) are the i-th and (i-1)-th time intervals. τ The corresponding pressure, S t ′ represents the dimensionless overall system stiffness. i For each time interval τ The index number, where n is the total number of time intervals. P p To measure the pore pressure of the rock mass, V L For the fluid leakage volume, V To analyze the volume, C This is a C function describing the pressure decay phase. V L The relative trend of change.

4. The geostress analysis platform according to claim 2, characterized in that, The hydraulic fracturing module is configured as follows: Identify pressure-time data from multiple iterations during the experiment; For each cycle, based on a preset characteristic slope threshold, three key characteristic moments within that cycle are automatically identified: the pump start-up moment, the pump stop-up moment, and the pressure relief moment. The pump start-up moment, the pump stop-up moment, and the pressure relief moment serve as the endpoints of the time interval required to calculate the key characteristic pressure parameters of ground stress. The characteristic slope threshold is set based on the data characteristics of the pump start-up moment, the pump stop-up moment, and the pressure relief moment, and has an adjustable initial value.

5. The geostress analysis platform according to claim 1, characterized in that, The equation relating the vertical stress to the weight of the overlying strata is expressed as: ； In the formula, l p , m p , n p These are the direction cosines between the vertical stress and the three principal strain axes, respectively. h To test the burial depth of the rock core samples, ρ The average density of rock from the surface to this depth. g It is the acceleration due to gravity. P 0 represents pore pressure. e m (t) represents the strain of the inelastic body. e 1( t ), e 2( t )and e 3( t () represent the inelastic deviatoric strains along the three principal strain axes, respectively. This represents vertical stress.

6. The geostress analysis platform according to claim 1, characterized in that, The expression for the value of k is: ； In the formula, Jas (t) represents the inelastic strain recovery compliance in shear mode; Jav (t) represents the volumetric mode inelastic strain recovery compliance.

7. The geostress analysis platform according to claim 1, characterized in that, The formulas for calculating the values ​​of the maximum principal stress, intermediate principal stress, minimum principal stress, maximum horizontal principal stress, minimum horizontal principal stress, and vertical stress based on the inelastic strain recovery strain data of salt rock are as follows: ； ； ； In the formula, ε a It is an inelastic recovering strain; l , m , n The direction cosine of the strain axis; σ z , τ yz , τ zx These are stress components; σ m The average stress; P 0 represents pore pressure; α T Δ is the linear thermal expansion coefficient; T (t) represents the temperature change during the measurement period; σ i Principal stress, e i (t) represents the inelastic deviatoric strain. e m (t) represents the strain of the inelastic body; i = 1, 2, 3; σ h For the minimum horizontal principal stress, σ x and σ y These represent the normal stress components along two mutually perpendicular coordinate axes in the horizontal direction. τ xy Let be the shear stress components in the xy plane.

8. The geostress analysis platform according to claim 1, characterized in that, The platform adopts a cloud platform architecture, which supports multiple users to operate online at the same time.

9. The geostress analysis platform according to claim 1, characterized in that, The stress polygon tool in the toolset module performs the following functions: Stress normalization and thermal stress calculation; Constraint line analysis and multi-stress state projection; Automatically generate stress polygon base maps for tunnel stability assessment.

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