Method, device and system for monitoring the near-field distribution of a hydraulic fracture network

Abstract

This invention provides a near-field monitoring method for the distribution morphology of hydraulic fracturing networks, comprising: arranging multiple roof monitoring holes in the roadways on both sides of the underground working face of a coal mine; installing electromagnetic signal sensors in each roof monitoring hole and on the anchor bolts of the roadway backfilling side to construct a full-space monitoring network covering the hydraulic fracturing layers; the data interpretation and processing module of the electromagnetic signal time-shift imaging analysis system includes a multi-field coupled mathematical model for analyzing and deriving real-time electromagnetic signal imaging; during hydraulic fracturing, the current field, electromagnetic field, and ion diffusion field during the development and propagation of rock fractures are monitored by electromagnetic signal sensors, and the monitoring results are input into the electromagnetic signal time-shift imaging analysis system for calculation, extraction of feature values, and inference of the fracturing network distribution morphology through the feature values. This invention can monitor the propagation path of fracturing fluid in rock strata in real time, invert the three-dimensional distribution morphology of the hydraulic fracturing network, and provide new technical support for the verification of the pressure relief effect of underground hydraulic fracturing in coal mines.

Description

Technical Field

[0001] This invention relates to the field of hydraulic fracturing monitoring technology in coal mines, and particularly to a method, device, and system for near-field monitoring of the distribution morphology of hydraulic fracturing networks. Background Technology

[0002] Underground coal mining often faces the condition of multiple thick and hard roofs on the working face. The roof is not easy to collapse in time, which often causes stress concentration and energy accumulation. When the suspended length of the roof exceeds its limit fracture step, the roof breaks instantly and releases a large amount of energy, which can easily cause strong dynamic mining pressure disasters such as hurricanes on the working face, deformation of hydraulic cylinders of support columns, and large deformation of surrounding rock in the roadway.

[0003] To address issues such as strong dynamic load mining pressure or dynamic disasters induced by thick and hard roofs, the current common practice in coal mines is to use directional long borehole segmented hydraulic fracturing technology. Although this technology has achieved effective control in field operations, the fracture network distribution morphology cannot be obtained during hydraulic fracturing, making it impossible to scientifically analyze the hydraulic fracturing distribution morphology and roof depressurization effect. As a result, the verification of hydraulic fracturing depressurization effect relies on data analysis such as the pressure intensity and step distance of the hydraulic supports after the working face has been mined to the fracturing area. This makes it impossible to achieve timely analysis and verification during the hydraulic fracturing process, posing a risk of dynamic disasters such as mine tremors and rockbursts or strong dynamic load mining pressure disasters induced when the working face is mined to the hydraulic fracturing blind zone. Summary of the Invention

[0004] The present invention aims to at least partially solve one of the technical problems in the related art.

[0005] To achieve the above objectives, this invention proposes a near-field monitoring method for the distribution morphology of hydraulically fractured networks, characterized by comprising the following steps:

[0006] S1. Multiple roof monitoring holes are arranged in the roadways on both sides of the working face. Electromagnetic signal sensors are installed in each roof monitoring hole and on the anchor bolts of the roadway sidewall. Each electromagnetic signal sensor is connected to the same data monitoring master station to build a full-space monitoring network covering the hydraulic fracturing layer. S2, the data interpretation and processing module of the electromagnetic signal time-shift imaging analysis system includes a multi-field coupled mathematical model for analyzing and deducing real-time imaging of electromagnetic signals, including the current field, electromagnetic field and ion diffusion field in the hydraulic fracturing process; S3. During the hydraulic fracturing process, electromagnetic signal sensors are used to monitor the current field, electromagnetic field, and ion diffusion field during the development and propagation of rock fractures. The monitoring results are then fed into an electromagnetic signal time-shift imaging analysis system for calculation, feature values ​​are extracted, and the distribution morphology of the hydraulic fracture network is inferred from the feature values.

[0007] This invention can monitor the propagation path (resistivity change characteristics) of fracturing fluid in the top plate in real time and invert the three-dimensional distribution morphology of the hydraulic fracturing network, thereby completing the dynamic verification of the pressure relief effect during hydraulic fracturing construction and providing new technology support for the verification of hydraulic fracturing pressure relief effect.

[0008] Optionally, in S1, when arranging roof monitoring holes, the spacing between multiple roof monitoring holes in the same side roadway is 150-250m, and the depth range of a single roof monitoring hole is 130-200m. When the hydraulic fracturing hole is designed directly above the roadway or on the side away from the working face, or above the working face, the far end of the roof monitoring hole is designed in a direction away from the hydraulic fracturing hole and the working face. The relative horizontal distance between the hydraulic fracturing hole and the roof monitoring hole is 50-60m. The angle between the roof monitoring hole and the horizontal direction is determined based on this spatial relationship. The vertical distance between the far end of the top plate monitoring hole and the fracturing layer must be greater than 30m.

[0009] Furthermore, the installation locations of the electromagnetic signal sensors include the anchor bolts in the roof monitoring holes and the anchor bolts in the roadway backfilling sidewalls; the installation spacing of the electromagnetic signal sensors in a single roof monitoring hole is 40-50m; the electromagnetic signal sensors on the anchor bolts in the roadway backfilling sidewalls are arranged at 40-50m intervals.

[0010] Furthermore, in S2, the governing equations of the current field during the hydraulic fracturing process include: Fluid continuity equation: ; in, For fluid density, The average velocity of the fluid, Porosity.

[0011] Darcy's Law for Fluids: ; Where v is the fluid velocity. For penetration rate, The dynamic viscosity of the fluid. For pressure, This represents the pressure gradient.

[0012] Furthermore, in S2, the electromagnetic field governing equations during the hydraulic fracturing process include: Navier-Stokes equations:

[0013] in, For fluid density, For fluid velocity, For pressure, The dynamic viscosity of the fluid. It is an external force.

[0014] Furthermore, in S2, the governing equation for the ion diffusion field during the hydraulic fracturing process includes: Convection-diffusion equation: ; in, For the first Seed ion concentration, ρ is the diffusion coefficient, and v is the fluid velocity.

[0015] Furthermore, S3 specifically includes: S31. Before hydraulic fracturing, based on the logging data of the top plate monitoring holes, the logging data of the fracturing holes, and the rock physical property test data, a three-dimensional distribution model of the initial resistivity is established, and the rock resistivity value, rock porosity, fracture density, temperature, pressure, and rock layer interface parameters are calibrated to form a full-space initial model of the fracturing area. S32. After the fracturing hole drilling is completed, a drilling pulse current transmitter is arranged in the fracturing hole. The drilling pulse current transmitter is powered by pulse. The electromagnetic signal sensor acquires the current field, electromagnetic field and ion diffusion field data of the area before fracturing. The multi-field coupling equation is solved by the finite element method to generate a multi-physics response database before fracturing. S33. Use the current field, electromagnetic field and ion diffusion field data obtained from the multiphysics response database before fracturing to modify the initial model and obtain an optimized model suitable for the current construction environment, providing a guiding basis for the fracturing process and the monitoring of the whole space monitoring area. S34. During the fracturing process, the borehole pulse current transmitter is powered by pulses. As the rock fractures develop and expand, the fracturing fluid migrates, causing changes in the regional current field, electromagnetic field, and ion diffusion field. The electromagnetic signal sensor in the full-space monitoring area acquires the change data and performs real-time moving imaging analysis on the data to form the full-space fracturing fluid expansion path and fracture distribution characteristics, and generates a multi-physics response database during the fracturing process. S35. Extract the spatial characteristics of the fracture distribution to invert the distribution morphology of the hydraulic pressure fracture network.

[0016] Furthermore, in step S32, spatial filtering technology is required to measure and calculate the potential difference between adjacent sensors to eliminate common-mode noise.

[0017] Furthermore, in S33, the various stages of fracture propagation are marked by combining the pressure-flow curve of the fracturing fluid injection during the fracturing process, including the initiation stage, the extension stage, and the branching stage.

[0018] Furthermore, in step S35, the specific steps of inverting the hydraulic fracturing network distribution morphology using spatial characteristics include: By calculating the unit gradient vector field, the direction of the maximum gradient is extracted as the main extension direction of the crack. Secondary gradient extrema are identified through tensor analysis, serving as crack branches; The crack length is determined by the distance the resistivity anomaly region extends along the main gradient; Estimate fracture width based on the relationship between resistivity variation and fracturing fluid conductivity; The complexity of the sewing mesh is quantitatively evaluated by using the fractal dimension of the resistivity anomaly region.

[0019] Furthermore, after completing step S3, the fabric spreading morphology needs to be verified. Verification methods include: By comparing the consistency between the propagation rate of the resistivity anomaly zone and the pumping rate, fracturing fluid front tracking is performed. The consistency error between the propagation rate of the resistivity anomaly zone and the pumping rate should be <5%. When the error exceeds 5%, the source of the error needs to be checked and supplementary verification measures need to be taken. Inspect the sources of error: check the accuracy and sampling frequency of the electromagnetic signal monitoring equipment, and check the calibration of the pump flow meter and pressure sensor; Supplementary verification methods were adopted: microseismic monitoring technology was used to analyze the spatiotemporal distribution of microseismic events in fracture development and propagation, and to determine whether the propagation direction of microseismic events matched the electromagnetic anomaly zone; tracer flowback analysis was adopted to monitor the peak time of tracer concentration in the flowback fluid after fracturing and to estimate the fracturing fluid migration velocity; and pump stop pressure analysis was adopted to invert the fracture closure pressure and filtration characteristics through the pressure drop curve after pumping was stopped.

[0020] Furthermore, when the error is 5% to 10%, priority should be given to checking data quality and equipment calibration, supplemented by tracer verification; When the error is 10% to 20%, multiple supplementary methods should be used for cross-validation. When the error exceeds 20%, operations are suspended, and geological-engineering collaborative analysis and dynamic testing are conducted to re-evaluate the fracturing plan.

[0021] Furthermore, the multiphysics response database before fracturing and the multiphysics response database during fracturing will be historically accumulated to provide historical reference data for new detection areas; Furthermore, the optimized models will be calibrated and stored one by one with the current construction environment to form a database of preferred models, providing optional construction monitoring models for other detection areas.

[0022] The present invention also provides an apparatus for near-field monitoring of the distribution morphology of hydraulically fractured networks using any of the coupling electric field principles described above, comprising multiple electromagnetic signal sensors, multiple electromagnetic signal acquisition instruments, a borehole pulse current transmitter, a data monitoring master station, and an electromagnetic signal time-shift imaging analysis system. Multiple electromagnetic signal sensors are arranged at the monitoring holes in the roof and at the anchor bolt positions of the roadway backfilling, and the multiple electromagnetic signal sensors are arranged at equal intervals. Multiple electromagnetic signal acquisition devices are used to acquire data obtained by electromagnetic signal sensors at different locations; and all of the multiple electromagnetic signal acquisition devices are electrically connected, network-linked, or wirelessly connected to the data monitoring master station. The borehole pulse current transmitter is arranged in the fracturing hole during hydraulic fracturing, and the borehole pulse current transmitter is connected to the hydraulic fracturing tool string. The data monitoring master station and the electromagnetic signal time-shift imaging analysis system are connected by an electrical connection, a network link, or a wireless connection. The electromagnetic signal time-shift imaging analysis system is configured to acquire data obtained by electromagnetic signal sensors and perform real-time motion imaging analysis to obtain the full-space fracturing fluid propagation path and fracture distribution characteristics.

[0023] This invention also provides a near-field monitoring system for the distribution morphology of hydraulically fractured networks, characterized in that it includes: The first module involves arranging multiple roof monitoring holes in the roadways on both sides of the working face, installing multiple electromagnetic signal sensors in each roof monitoring hole and on the anchor bolts of the roadway back mining side, and electrically connecting each electromagnetic signal sensor to the same data monitoring master station to construct a full-space monitoring network. In the first unit, the spacing between multiple roof monitoring holes in the same side roadway is 150-250m, and the depth range of a single roof monitoring hole is 130-200m. When the hydraulic fracturing hole is designed directly above the roadway or on the side away from the working face, or above the working face, the far end of the roof monitoring hole is designed in a direction away from the hydraulic fracturing hole and the working face. The relative horizontal distance between the hydraulic fracturing hole and the roof monitoring hole is 50-60m. The angle between the roof monitoring hole and the horizontal direction is determined based on this spatial relationship. The vertical distance between the far end of the roof monitoring hole and the fracturing layer needs to be >30m, and the electromagnetic signal sensors on the roadway backfill anchor bolts should be arranged at 40-50m. The second unit includes the installation locations of electromagnetic signal sensors, including the anchor bolts in the monitoring holes of the roadway roof and the anchor bolts of the roadway mining side; the installation spacing of electromagnetic signal sensors in a single roof monitoring hole is 40-50m, and the electromagnetic signal sensors on the anchor bolts of the roadway mining side are arranged at 40-50m intervals. The second module, the data interpretation and processing module of the electromagnetic signal time-shift imaging analysis system, includes the analysis and deduction of multi-field coupled mathematical models for real-time imaging of electromagnetic signals, including the current field, electromagnetic field and ion diffusion field in the hydraulic fracturing process; The third unit covers the governing equations of the current field in the hydraulic fracturing process, including: Fluid continuity equation: ; in, For fluid density, The average velocity of the fluid, Porosity.

[0024] Darcy's Law for Fluids: ; Where v is the fluid velocity. For penetration rate, The dynamic viscosity of the fluid. For pressure, For pressure gradient; Unit Four, the electromagnetic field governing equations in the hydraulic fracturing process include: Navier-Stokes equations: ; in, For fluid density, For fluid velocity, For pressure, The dynamic viscosity of the fluid. External force; Unit 5, the governing equations of the ion diffusion field in the hydraulic fracturing process include: Convection-diffusion equation: ; in, For the first Seed ion concentration, Where is the diffusion coefficient, and v is the fluid velocity; The third module involves monitoring the current field, electromagnetic field, and ion diffusion field during the development and propagation of rock fractures using electromagnetic signal sensors. The monitoring results are then fed into an electromagnetic signal time-shift imaging analysis system for calculation, feature values ​​are extracted, and the fracture network distribution morphology is inferred from these feature values. Unit 6: Before hydraulic fracturing, based on the logging data of the top plate monitoring holes, the logging data of the fracturing holes, and the rock physical property test data, a three-dimensional distribution model of the initial resistivity is established, and the rock resistivity value, rock porosity, fracture density, temperature, pressure, and rock interface parameters are calibrated to form a full-space initial model of the fracturing area. In Unit 7, after the fracturing hole drilling is completed, the borehole pulse current transmitter is powered by pulses, and the electromagnetic signal sensor acquires the current field, electromagnetic field, and ion diffusion field data of the area before fracturing. The finite element method is used to solve the multi-field coupling equations and generate a multi-physics response database before fracturing. The eighth unit requires the use of spatial filtering techniques to measure and calculate the potential difference between adjacent sensors to eliminate common-mode noise. The ninth unit uses the current field, electromagnetic field, and ion diffusion field data obtained from the multiphysics response database before fracturing to revise the initial model and obtain an optimized model suitable for the current construction environment, providing a guiding basis for the fracturing process and the monitoring of the entire space monitoring area. Unit 10: During the fracturing process, the borehole pulse current transmitter is powered by pulses. As the rock fractures develop and expand, the fracturing fluid migrates, causing changes in the regional current field, electromagnetic field, and ion diffusion field. Electromagnetic signal sensors in the full-space monitoring area acquire the change data and perform real-time moving imaging analysis on the data to form the spatial characteristics of the fracturing fluid expansion path and fracture distribution in the full space, and generate a multi-physics response database during the fracturing process. Unit 11: Extracting the spatial characteristics of fracture distribution to invert the distribution morphology of hydraulically pressure-induced fracture networks; Unit 12, combining the pressure-flow rate curves of the fracturing fluid injection during the fracturing process, marks the various stages of fracture propagation, including the initiation stage, the extension stage, and the branching stage. Unit 13, which utilizes spatial characteristics to invert the distribution morphology of hydraulically pressure-induced fracture networks, specifically includes: By calculating the unit gradient vector field, the direction of the maximum gradient is extracted as the main extension direction of the crack. Secondary gradient extrema are identified through tensor analysis, serving as crack branches; The crack length is determined by the distance the resistivity anomaly region extends along the main gradient; Estimate fracture width based on the relationship between resistivity variation and fracturing fluid conductivity; The complexity of the sewing mesh is quantitatively evaluated by using the fractal dimension of the resistivity anomaly region. Unit Fourteen involves historically accumulating the multiphysics response database before fracturing and the multiphysics response database during fracturing to provide historical reference data for new detection areas. Unit 15 involves calibrating and storing the optimized models against the current construction environment to form a database of preferred models, providing optional construction monitoring models for other detection areas. The fourth module verifies the fabric spreading morphology of the sewn mesh. The verification methods include: By comparing the consistency between the propagation rate of the resistivity anomaly zone and the pumping rate, fracturing fluid front tracking is performed. The consistency error between the propagation rate of the resistivity anomaly zone and the pumping rate should be <5%. When the error exceeds 5%, the source of the error needs to be checked and supplementary verification measures need to be taken. Unit 16, Checking the Sources of Error: Checking the accuracy and sampling frequency of the electromagnetic signal monitoring equipment, and checking the calibration of the pump flow meter and pressure sensor; Unit 17 employs supplementary verification methods: microseismic monitoring technology is used to analyze the spatiotemporal distribution of microseismic events related to fracture development and propagation, determining whether the propagation direction of microseismic events matches the electromagnetic anomaly zone; tracer flowback analysis is used to monitor the peak time of tracer concentration in the flowback fluid after fracturing, estimating the fracturing fluid migration velocity; and pump stop pressure analysis is used to invert the fracture closure pressure and filtration characteristics through pressure drop curves after pumping is suspended. Unit 18: When the error is 5% to 10%, prioritize checking data quality and equipment calibration, supplemented by tracer verification. When the error is 10% to 20%, multiple supplementary methods should be used for cross-validation. When the error exceeds 20%, operations are suspended, and geological-engineering collaborative analysis and dynamic testing are conducted to re-evaluate the fracturing plan.

[0025] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0026] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein: Figure 1 This is a schematic diagram illustrating the steps of the near-field monitoring method and apparatus for the distribution morphology of hydraulically fractured networks according to the present invention; Figure 2 This is a schematic diagram of the detailed steps of S3 in the near-field monitoring method and device for the distribution morphology of hydraulically fractured networks according to the present invention; Figure 3 This is an installation diagram of the near-field monitoring method and device for the distribution morphology of hydraulically fractured networks according to the present invention (taking the device arranged in one side of the roadway as an example). Figure 4 This is a schematic diagram of the near-field monitoring method and device for the hydraulic pressure fracture network distribution morphology according to the present invention.

[0027] Explanation of reference numerals in the attached figures: 1. Electromagnetic signal sensor; 2. Electromagnetic signal acquisition instrument; 3. Drilling pulse current transmitter; 4. Data monitoring master station; 5. Electromagnetic signal time-shift imaging analysis system; 6. Top plate monitoring hole. Detailed Implementation

[0028] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0029] In coal mines, directional long boreholes are often drilled in sections to create hydraulic fracturing layers 30-100m above the coal seam. Because there are roadway works in the fracturing area, hydraulic fracturing can be carried out in the underground roadway chambers to the roof of the coal seam within a range of 30-100m above the coal seam. Therefore, boreholes can be drilled in the underground roadway to monitor the hydraulic fracturing network. Microseismic monitoring and other techniques are used to monitor the hydraulic fracturing layers near the roof relative to the ground (about 400-500m from the coal seam).

[0030] Based on the above explanation of near-field monitoring of hydraulic fracturing in coal mines, this invention provides a near-field monitoring method for the distribution morphology of hydraulic fracturing fracture networks, as described below. Figures 1 to 4 Please provide a detailed explanation.

[0031] A near-field monitoring method for the distribution morphology of hydraulically fractured networks includes the following steps: S1. Multiple roof monitoring holes 6 are arranged in the roadways on both sides of the working face. Electromagnetic signal sensors 1 are installed in each roof monitoring hole 6 and on the anchor bolts of the roadway sidewall. Each electromagnetic signal sensor 1 is connected to the same data monitoring master station 4 to build a full-space monitoring network covering the hydraulic fracturing layer. S2, the data interpretation and processing module of the electromagnetic signal time-shift imaging analysis system 5 includes a multi-field coupled mathematical model for analyzing and deducing real-time imaging of electromagnetic signals, including the current field, electromagnetic field and ion diffusion field in the hydraulic fracturing process; S3. During the hydraulic fracturing process, the current field, electromagnetic field and ion diffusion field of the rock mass fracture development and propagation are monitored by electromagnetic signal sensor 1. The monitoring results are brought into electromagnetic signal time-shift imaging analysis system 5 for calculation, feature values ​​are extracted, and the fracture network distribution morphology is inferred through the feature values.

[0032] This invention can monitor the propagation path (resistivity change characteristics) of fracturing fluid in the top plate in real time and invert the three-dimensional distribution morphology of the hydraulic fracturing network, thereby completing the dynamic verification of the pressure relief effect during hydraulic fracturing construction and providing new technology support for the verification of hydraulic fracturing pressure relief effect.

[0033] In some embodiments, in S1, when arranging the roof monitoring holes 6, the spacing between multiple roof monitoring holes 6 in the same side roadway is 150-250m, and the depth range of a single roof monitoring hole 6 is 130-200m. When the hydraulic fracturing hole is designed directly above the roadway or on the side away from the working face, or above the working face, the far end of the roof monitoring hole 6 is designed in a direction away from the hydraulic fracturing hole and the working face. The relative horizontal distance between the hydraulic fracturing hole and the roof monitoring hole 6 is 50-60m. The angle between the roof monitoring hole 6 and the horizontal direction is determined based on this spatial relationship. The vertical distance between the far end of monitoring hole 6 in the top plate and the fracturing layer needs to be >30m.

[0034] In some embodiments, the installation locations of the electromagnetic signal sensor 1 include the anchor bolts in the roadway roof monitoring holes 6 and the roadway backfilling anchor bolts; the installation spacing of the electromagnetic signal sensor 1 in a single roof monitoring hole 6 is 40-50m; the electromagnetic signal sensor 1 on the roadway backfilling anchor bolts is arranged at 40-50m intervals.

[0035] In some embodiments, in S2, the current field governing equations during the hydraulic fracturing process include: Fluid continuity equation: ; in, For fluid density, The average velocity of the fluid, Porosity.

[0036] Darcy's Law for Fluids: ; Where v is the fluid velocity. For penetration rate, The dynamic viscosity of the fluid. For pressure, This represents the pressure gradient.

[0037] In some embodiments, in S2, the electromagnetic field governing equations during the hydraulic fracturing process include: Navier-Stokes equations (i.e., equations for high-speed flow of fracturing fluids):

[0038] in, For fluid density, For fluid velocity, For pressure, The dynamic viscosity of the fluid. External forces, such as electric field forces.

[0039] In some embodiments, in S2, the governing equation for the ion diffusion field during hydraulic fracturing includes: Convection-diffusion equation: ; in, For the first Seed ion concentration, ρ is the diffusion coefficient, and v is the fluid velocity.

[0040] In some embodiments, S3 specifically includes: S31. Before hydraulic fracturing, based on the logging data of the top plate monitoring hole 6, the logging data of the fracturing hole, and the rock physical property test data, a three-dimensional distribution model of the initial resistivity is established, and the rock resistivity value, rock porosity, fracture density, temperature, pressure and rock layer interface parameters are calibrated to form a full-space initial model of the fracturing area. S32. After the fracturing hole drilling is completed, a drilling pulse current transmitter 3 is arranged in the fracturing hole. The drilling pulse current transmitter 3 is powered by pulse. The electromagnetic signal sensor 1 acquires the current field, electromagnetic field and ion diffusion field data of the area before fracturing. The multi-field coupling equation is solved by the finite element method to generate a multi-physics response database before fracturing. S33. Use the current field, electromagnetic field and ion diffusion field data obtained from the multiphysics response database before fracturing to modify the initial model and obtain an optimized model suitable for the current construction environment, providing a guiding basis for the fracturing process and the monitoring of the whole space monitoring area. S34. During the fracturing process, the borehole pulse current transmitter 3 is powered by pulse. As the rock fracture develops and expands, the fracturing fluid migrates, causing changes in the regional current field, electromagnetic field and ion diffusion field. The electromagnetic signal sensor 1 in the full-space monitoring area acquires the change data and performs real-time moving imaging analysis on the data to form the full-space fracturing fluid expansion path and fracture distribution characteristics, and generate a multi-physics response database during the fracturing process. S35. Extract the spatial characteristics of the fracture distribution to invert the distribution morphology of the hydraulic pressure fracture network.

[0041] When the top plate remains undisturbed and undamaged, its original resistivity distribution is stable. An initial model of the full-space electric field is created by collecting the original resistivity distribution characteristics of the fracturing area. During hydraulic fracturing, fracturing water or fracturing fluid is commonly used. Due to the different sources of these fluids, their resistivity often differs from that of the top plate region. When fracturing begins, fracturing water or fracturing fluid is injected into the borehole space of the top plate until the pressure exceeds the rock initiation pressure. The fracturing fluid then expands along weak surfaces such as bedding planes in the top plate region, causing a change in the full-space electric field model relative to the initial state. By collecting real-time data on these changes, the expansion path and spatial characteristics of the fracturing fluid during hydraulic fracturing can be obtained, and the fracturing fracture network distribution morphology can be derived through inversion.

[0042] In some embodiments, in step S32, spatial filtering technology is used to measure and calculate the potential difference between adjacent sensors to eliminate common-mode noise. In some embodiments, in S33, the various stages of fracture propagation, including the initiation stage, the extension stage, and the branching stage, are marked by combining the pressure-flow curve of the fracturing fluid injected during the fracturing process.

[0043] In some embodiments, S35, the inversion of the hydraulic fracturing network distribution morphology using spatial characteristics specifically includes: By calculating the unit gradient vector field, the direction of the maximum gradient is extracted as the main extension direction of the crack. Secondary gradient extrema are identified through tensor analysis, serving as crack branches; The crack length is determined by the distance the resistivity anomaly region extends along the main gradient; Estimate fracture width based on the relationship between resistivity variation and fracturing fluid conductivity; The complexity of the sewing mesh is quantitatively evaluated by using the fractal dimension of the resistivity anomaly region.

[0044] In some embodiments, the multiphysics response database before fracturing and the multiphysics response database during fracturing are historically accumulated to provide historical reference data for new detection areas. Furthermore, the optimized models will be calibrated and stored one by one with the current construction environment to form a database of preferred models, providing optional construction monitoring models for other detection areas.

[0045] In some embodiments, after completing step S3, it is necessary to verify the fabric layout of the sewn mesh. The verification method includes: By comparing the consistency between the propagation rate of the resistivity anomaly zone and the pumping rate, fracturing fluid front tracking is performed. The consistency error between the propagation rate of the resistivity anomaly zone and the pumping rate should be <5%. When the error exceeds 5%, the source of the error needs to be checked and supplementary verification measures need to be taken. Inspect the sources of error: check the accuracy and sampling frequency of the electromagnetic signal monitoring equipment, and check the calibration of the pump flow meter and pressure sensor; Supplementary verification methods were adopted: microseismic monitoring technology was used to analyze the spatiotemporal distribution of microseismic events in fracture development and propagation, and to determine whether the propagation direction of microseismic events matched the electromagnetic anomaly zone; tracer flowback analysis was adopted to monitor the peak time of tracer concentration in the flowback fluid after fracturing and to estimate the fracturing fluid migration velocity; and pump stop pressure analysis was adopted to invert the fracture closure pressure and filtration characteristics through the pressure drop curve after pumping was stopped.

[0046] In some embodiments, when the error is 5% to 10%, data quality and equipment calibration are checked first, supplemented by tracer verification; When the error is 10% to 20%, multiple supplementary methods should be used for cross-validation. When the error exceeds 20%, operations are suspended, and geological-engineering collaborative analysis and dynamic testing are conducted to re-evaluate the fracturing plan.

[0047] The present invention also provides an apparatus for near-field monitoring of the distribution morphology of hydraulically fractured networks using any of the above-mentioned methods, including multiple electromagnetic signal sensors 1, multiple electromagnetic signal acquisition instruments 2, a borehole pulse current transmitter 3, a data monitoring master station 4, and an electromagnetic signal time-shift imaging analysis system 5. Multiple electromagnetic signal sensors 1 are arranged at the monitoring holes 6 in the roof and at the anchor bolt positions of the roadway backfilling, and the multiple electromagnetic signal sensors 1 are arranged at equal intervals. Multiple electromagnetic signal acquisition devices 2 are used to acquire data obtained by electromagnetic signal sensors 1 at different locations; and all of the multiple electromagnetic signal acquisition devices 2 are electrically connected, network-linked, or wirelessly connected to the data monitoring master station 4. The borehole pulse current transmitter 3 is arranged in the fracturing hole during hydraulic fracturing, and the borehole pulse current transmitter 3 is connected to the hydraulic fracturing tool string. The data monitoring master station 4 and the electromagnetic signal time-shift imaging analysis system 5 are connected by electrical, network, or wireless means. Since the electromagnetic signal time-shift imaging analysis system 5 is mostly located on the ground, the data monitoring master station 4 and the electromagnetic signal time-shift imaging analysis system 5 are preferably connected wirelessly. The electromagnetic signal time-shift imaging analysis system 5 is configured to acquire data obtained by the electromagnetic signal sensor 1 and perform real-time motion imaging analysis to obtain the full-space fracturing fluid propagation path and fracture distribution characteristics.

[0048] In some embodiments, the electrical signal probe employs a high-sensitivity Ag / AgCl non-polarizing electrode with a resolution of 0.1mV. The borehole pulse current emission probe is pulse-powered (frequency 0.1-10Hz) with a supply current intensity of 5-100A and uses a high-power aluminum alloy electrode.

[0049] This invention also provides a near-field monitoring system for the distribution morphology of hydraulically fractured networks, comprising: The first module involves arranging multiple roof monitoring holes 6 in the roadways on both sides of the working face, installing multiple electromagnetic signal sensors 1 in each roof monitoring hole 6 and on the anchor bolts of the roadway back mining side, and electrically connecting each electromagnetic signal sensor 1 to the same data monitoring master station 4 to construct a full-space monitoring network. In the first unit, the multiple roof monitoring holes 6 in the same side roadway are arranged at intervals of 150-250m, and the depth range of a single roof monitoring hole 6 is 130-200m; When the hydraulic fracturing hole is designed directly above the roadway or on the side away from the working face, or above the working face, the far end of the roof monitoring hole 6 is designed in a direction away from the hydraulic fracturing hole and the working face. The relative horizontal distance between the hydraulic fracturing hole and the roof monitoring hole 6 is 50-60m. The angle between the roof monitoring hole 6 and the horizontal direction is determined based on this spatial relationship. The vertical distance between the far end of the roof monitoring hole 6 and the fracturing layer needs to be >30m, and the electromagnetic signal sensor 1 on the roadway backfill anchor bolt should be arranged at 40-50m. The second unit, the installation locations of electromagnetic signal sensor 1 include the anchor bolts in the roadway roof monitoring hole 6 and the roadway backfilling side anchor bolts; the installation spacing of electromagnetic signal sensor 1 in a single roof monitoring hole 6 is 40-50m, and the electromagnetic signal sensor 1 on the roadway backfilling side anchor bolts is arranged at 40-50m. The second module, the data interpretation and processing module of the electromagnetic signal time-shift imaging analysis system 5, includes a multi-field coupled mathematical model for analyzing and deducing real-time imaging of electromagnetic signals, including the current field, electromagnetic field and ion diffusion field in the hydraulic fracturing process. The third unit covers the governing equations of the current field in the hydraulic fracturing process, including: Fluid continuity equation: ; in, For fluid density, The average velocity of the fluid, Porosity.

[0050] Darcy's Law for Fluids: ; Where v is the fluid velocity. For penetration rate, The dynamic viscosity of the fluid. For pressure, For pressure gradient; Unit Four, the electromagnetic field governing equations in the hydraulic fracturing process include: Navier-Stokes equations: ; in, For fluid density, For fluid velocity, For pressure, The dynamic viscosity of the fluid. External force; Unit 5, the governing equations of the ion diffusion field in the hydraulic fracturing process include: Convection-diffusion equation: ; in, For the first Seed ion concentration, Where is the diffusion coefficient, and v is the fluid velocity; In the third module, during the hydraulic fracturing process, the current field, electromagnetic field and ion diffusion field of the rock mass fracture development and propagation are monitored by electromagnetic signal sensor 1. The monitoring results are then fed into electromagnetic signal time-shift imaging analysis system 5 for calculation, feature values ​​are extracted, and the fracture network distribution morphology is inferred from the feature values. Unit 6, before hydraulic fracturing, based on the logging data of the top plate monitoring hole 6, the fracturing hole logging data, and the rock physical property test data, establish a three-dimensional distribution model of the initial resistivity, calibrate the rock resistivity value, rock porosity, fracture density, temperature, pressure, and rock layer interface parameters, and form a full-space initial model of the fracturing area; In Unit 7, after the fracturing hole drilling is completed, the drilling pulse current transmitter 3 is powered by pulse, and the electromagnetic signal sensor 1 acquires the current field, electromagnetic field, and ion diffusion field data of the area before fracturing. The multi-field coupling equation is solved using the finite element method to generate a multi-physics response database before fracturing. The eighth unit requires the use of spatial filtering techniques to measure and calculate the potential difference between adjacent sensors to eliminate common-mode noise. The ninth unit uses the current field, electromagnetic field, and ion diffusion field data obtained from the multiphysics response database before fracturing to revise the initial model and obtain an optimized model suitable for the current construction environment, providing a guiding basis for the fracturing process and the monitoring of the entire space monitoring area. Unit 10: During the fracturing process, the borehole pulse current transmitter 3 is powered by pulses. As the rock fractures develop and expand, the fracturing fluid migrates, causing changes in the regional current field, electromagnetic field, and ion diffusion field. The electromagnetic signal sensor 1 in the full-space monitoring area acquires the change data and performs real-time moving imaging analysis on the data to form the spatial characteristics of the fracturing fluid expansion path and fracture distribution in the full space, and generates a multi-physics response database during the fracturing process. Unit 11: Extracting the spatial characteristics of fracture distribution to invert the distribution morphology of hydraulically pressure-induced fracture networks; Unit 12, combining the pressure-flow rate curves of the fracturing fluid injection during the fracturing process, marks the various stages of fracture propagation, including the initiation stage, the extension stage, and the branching stage. Unit 13, which utilizes spatial characteristics to invert the distribution morphology of hydraulically pressure-induced fracture networks, specifically includes: By calculating the unit gradient vector field, the direction of the maximum gradient is extracted as the main extension direction of the crack. Secondary gradient extrema are identified through tensor analysis, serving as crack branches; The crack length is determined by the distance the resistivity anomaly region extends along the main gradient; Estimate fracture width based on the relationship between resistivity variation and fracturing fluid conductivity; The complexity of the sewing mesh is quantitatively evaluated by using the fractal dimension of the resistivity anomaly region. Unit Fourteen involves historically accumulating the multiphysics response database before fracturing and the multiphysics response database during fracturing to provide historical reference data for new detection areas. Unit 15 involves calibrating and storing the optimized models against the current construction environment to form a database of preferred models, providing optional construction monitoring models for other detection areas. The fourth module verifies the fabric spreading morphology of the sewn mesh. The verification methods include: By comparing the consistency between the propagation rate of the resistivity anomaly zone and the pumping rate, fracturing fluid front tracking is performed. The consistency error between the propagation rate of the resistivity anomaly zone and the pumping rate should be <5%. When the error exceeds 5%, the source of the error needs to be checked and supplementary verification measures need to be taken. Unit 16, Checking the Sources of Error: Checking the accuracy and sampling frequency of the electromagnetic signal monitoring equipment, and checking the calibration of the pump flow meter and pressure sensor; Unit 17 employs supplementary verification methods: microseismic monitoring technology is used to analyze the spatiotemporal distribution of microseismic events related to fracture development and propagation, determining whether the propagation direction of microseismic events matches the electromagnetic anomaly zone; tracer flowback analysis is used to monitor the peak time of tracer concentration in the flowback fluid after fracturing, estimating the fracturing fluid migration velocity; and pump stop pressure analysis is used to invert the fracture closure pressure and filtration characteristics through pressure drop curves after pumping is suspended. Unit 18: When the error is 5% to 10%, prioritize checking data quality and equipment calibration, supplemented by tracer verification. When the error is 10% to 20%, multiple supplementary methods should be used for cross-validation. When the error exceeds 20%, operations are suspended, and geological-engineering collaborative analysis and dynamic testing are conducted to re-evaluate the fracturing plan.

[0051] The present invention also provides a computer-readable storage medium storing executable instructions for a near-field monitoring system for the distribution morphology of hydraulically fractured networks as described above, wherein the instructions, when executed, can implement the near-field monitoring method for the distribution morphology of hydraulically fractured networks as described in any of the preceding claims.

[0052] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0053] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0054] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0055] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0056] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0057] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for near-field monitoring of hydraulic fracture network geometry, characterized in that, Includes the following steps: S1. Multiple roof monitoring holes are arranged in the roadways on both sides of the working face. Electromagnetic signal sensors are installed in each roof monitoring hole and on the anchor bolts of the roadway sidewall. Each electromagnetic signal sensor is connected to the same data monitoring master station to build a full-space monitoring network covering the hydraulic fracturing layer. S2, the data interpretation and processing module of the electromagnetic signal time-shift imaging analysis system includes a multi-field coupled mathematical model for analyzing and deducing real-time imaging of electromagnetic signals, including the current field, electromagnetic field and ion diffusion field in the hydraulic fracturing process; The governing equations for the current field in the hydraulic fracturing process include: Fluid continuity equation: ; in, For fluid density, The average velocity of the fluid, Porosity; Darcy's Law for Fluids: ; Where v is the fluid velocity. For penetration rate, The dynamic viscosity of the fluid. For pressure, For pressure gradient; The electromagnetic field governing equations in the hydraulic fracturing process include: Navier-Stokes equations: ; in, For fluid density, For fluid velocity, For pressure, The dynamic viscosity of the fluid. External force; The governing equations for the ion diffusion field in hydraulic fracturing include: Convection-diffusion equation: ; in, For the first Seed ion concentration, Where is the diffusion coefficient, and v is the fluid velocity; S3. During the hydraulic fracturing process, electromagnetic signal sensors are used to monitor the current field, electromagnetic field, and ion diffusion field during the development and propagation of rock fractures. The monitoring results are then fed into an electromagnetic signal time-shift imaging analysis system for calculation, feature values ​​are extracted, and the distribution morphology of the hydraulic fracture network is inferred from the feature values.

2. The near-field monitoring method for the distribution morphology of hydraulically fractured networks as described in claim 1, characterized in that, In S1, when arranging roof monitoring holes, the spacing between multiple roof monitoring holes in the same side roadway is 150-250m, and the depth range of a single roof monitoring hole is 130-200m. When the hydraulic fracturing hole is designed directly above the roadway or on the side away from the working face, or above the working face, the far end of the roof monitoring hole is designed in a direction away from the hydraulic fracturing hole and the working face. The relative horizontal distance between the hydraulic fracturing hole and the roof monitoring hole is 50-60m. The angle between the roof monitoring hole and the horizontal direction is determined based on this spatial relationship. The vertical distance between the far end of the top plate monitoring hole and the fracturing layer must be greater than 30m.

3. The near-field monitoring method for the distribution morphology of hydraulically fractured networks as described in claim 2, characterized in that, The installation locations for electromagnetic signal sensors include the anchor bolts in the roof monitoring holes and the anchor bolts in the roadway backfilling sidewalls; the installation spacing of electromagnetic signal sensors in a single roof monitoring hole is 40-50m; the electromagnetic signal sensors on the anchor bolts in the roadway backfilling sidewalls are arranged at 40-50m intervals.

4. The near-field monitoring method for the distribution morphology of hydraulically fractured networks as described in claim 1, characterized in that, In S3, specifically including: S31. Before hydraulic fracturing, based on the logging data of the top plate monitoring holes, the logging data of the fracturing holes, and the rock physical property test data, a three-dimensional distribution model of the initial resistivity is established, and the rock resistivity value, rock porosity, fracture density, temperature, pressure, and rock layer interface parameters are calibrated to form a full-space initial model of the fracturing area. S32. After the fracturing hole drilling is completed, a drilling pulse current transmitter is arranged in the fracturing hole. The drilling pulse current transmitter is powered by pulse. The electromagnetic signal sensor acquires the current field, electromagnetic field and ion diffusion field data of the area before fracturing. The multi-field coupling equation is solved by the finite element method to generate a multi-physics response database before fracturing. S33. Use the current field, electromagnetic field and ion diffusion field data obtained from the multiphysics response database before fracturing to modify the initial model and obtain an optimized model suitable for the current construction environment, providing a guiding basis for the fracturing process and the monitoring of the whole space monitoring area. S34. During the fracturing process, the borehole pulse current transmitter is powered by pulses. As the rock fractures develop and expand, the fracturing fluid migrates, causing changes in the regional current field, electromagnetic field, and ion diffusion field. The electromagnetic signal sensor in the full-space monitoring area acquires the change data and performs real-time moving imaging analysis on the data to form the full-space fracturing fluid expansion path and fracture distribution characteristics, and generate a multi-physics response database during the fracturing process. S35. Extract the spatial characteristics of the fracture distribution to invert the distribution morphology of the hydraulic pressure fracture network.

5. The near-field monitoring method for the distribution morphology of hydraulically fractured networks as described in claim 4, characterized in that, In step S32, spatial filtering technology is required to measure and calculate the potential difference between adjacent sensors to eliminate common-mode noise.

6. The near-field monitoring method for the distribution morphology of hydraulically fractured networks as described in claim 4, characterized in that, In S33, the pressure-flow rate curve of the fracturing fluid injection during the fracturing process is used to mark the various stages of fracture propagation, including the initiation stage, the extension stage, and the branching stage.

7. The near-field monitoring method for the distribution morphology of hydraulically fractured networks as described in claim 4, characterized in that, In step S35, the spatial characteristics of fracture distribution are extracted to invert the morphology of hydraulically pressure-induced fracture network distribution, specifically including: By calculating the unit gradient vector field, the direction of the maximum gradient is extracted as the main extension direction of the crack. Secondary gradient extrema are identified through tensor analysis, serving as crack branches; The crack length is determined by the distance the resistivity anomaly region extends along the main gradient; Estimate fracture width based on the relationship between resistivity variation and fracturing fluid conductivity; The complexity of the sewing mesh is quantitatively evaluated by using the fractal dimension of the resistivity anomaly region.

8. The near-field monitoring method for the distribution morphology of hydraulically fractured networks as described in claim 4, characterized in that, After completing step S3, the fabric layout needs to be verified. Verification methods include: By comparing the consistency between the propagation rate of the resistivity anomaly zone and the pumping rate, fracturing fluid front tracking is performed. The consistency error between the propagation rate of the resistivity anomaly zone and the pumping rate should be <5%. When the error exceeds 5%, the source of the error needs to be checked and supplementary verification measures need to be taken. Inspect the sources of error: check the accuracy and sampling frequency of the electromagnetic signal monitoring equipment, and check the calibration of the pump flow meter and pressure sensor; Supplementary verification methods were adopted: microseismic monitoring technology was used to analyze the spatiotemporal distribution of microseismic events in fracture development and propagation, and to determine whether the propagation direction of microseismic events matched the electromagnetic anomaly zone; tracer flowback analysis was adopted to monitor the peak time of tracer concentration in the flowback fluid after fracturing and to estimate the fracturing fluid migration velocity; and pump stop pressure analysis was adopted to invert the fracture closure pressure and filtration characteristics through the pressure drop curve after pumping was stopped.

9. The near-field monitoring method for the distribution morphology of hydraulically fractured networks as described in claim 8, characterized in that, When the error is 5% to 10%, prioritize checking data quality and equipment calibration, supplemented by tracer verification; When the error is 10% to 20%, multiple supplementary methods should be used for cross-validation. When the error exceeds 20%, operations are suspended, and geological-engineering collaborative analysis and dynamic testing are conducted to re-evaluate the fracturing plan.

10. The near-field monitoring method for the distribution morphology of hydraulically fractured networks as described in claim 4, characterized in that, The multiphysics response database before fracturing and the multiphysics response database during fracturing are historically accumulated to provide historical reference data for new detection areas. Furthermore, the optimized models will be calibrated and stored one by one with the current construction environment to form a database of preferred models, providing optional construction monitoring models for other detection areas.

11. A near-field monitoring system for the distribution morphology of hydraulically fractured networks, characterized in that, include: The first module involves arranging multiple roof monitoring holes in the roadways on both sides of the working face, installing multiple electromagnetic signal sensors in each roof monitoring hole and on the anchor bolts of the roadway back mining side, and electrically connecting each electromagnetic signal sensor to the same data monitoring master station to construct a full-space monitoring network. In the first unit, the spacing between multiple roof monitoring holes in the same side roadway is 150-250m, and the depth range of a single roof monitoring hole is 130-200m. When the hydraulic fracturing hole is designed directly above the roadway or on the side away from the working face, or above the working face, the far end of the roof monitoring hole is designed in a direction away from the hydraulic fracturing hole and the working face. The relative horizontal distance between the hydraulic fracturing hole and the roof monitoring hole is 50-60m. The angle between the roof monitoring hole and the horizontal direction is determined based on this spatial relationship. The vertical distance between the far end of the roof monitoring hole and the fracturing layer needs to be >30m, and the electromagnetic signal sensors on the roadway backfill anchor bolts should be arranged at 40-50m. The second unit includes the installation locations of electromagnetic signal sensors, including the anchor bolts in the monitoring holes of the roadway roof and the anchor bolts of the roadway mining side; the installation spacing of electromagnetic signal sensors in a single roof monitoring hole is 40-50m, and the electromagnetic signal sensors on the anchor bolts of the roadway mining side are arranged at 40-50m intervals. The second module, the data interpretation and processing module of the electromagnetic signal time-shift imaging analysis system, includes the analysis and deduction of multi-field coupled mathematical models for real-time imaging of electromagnetic signals, including the current field, electromagnetic field and ion diffusion field in the hydraulic fracturing process; The third unit, the governing equations of the current field in the hydraulic fracturing process, include: Fluid continuity equation: ; in, For fluid density, The average velocity of the fluid, Porosity; Darcy's Law for Fluids: ; Where v is the fluid velocity. For penetration rate, The dynamic viscosity of the fluid. For pressure, For pressure gradient; Unit Four, the electromagnetic field governing equations in the hydraulic fracturing process include: Navier-Stokes equations: ; in, For fluid density, For fluid velocity, For pressure, The dynamic viscosity of the fluid. External force; Unit 5, the governing equations of the ion diffusion field in the hydraulic fracturing process include: Convection-diffusion equation: ; in, For the first Seed ion concentration, Where is the diffusion coefficient, and v is the fluid velocity; The third module involves monitoring the current field, electromagnetic field, and ion diffusion field during the development and propagation of rock fractures using electromagnetic signal sensors. The monitoring results are then fed into an electromagnetic signal time-shift imaging analysis system for calculation, feature values ​​are extracted, and the fracture network distribution morphology is inferred from these feature values. Unit 6: Before hydraulic fracturing, based on the logging data of the top plate monitoring holes, the logging data of the fracturing holes, and the rock physical property test data, a three-dimensional distribution model of the initial resistivity is established, and the rock resistivity value, rock porosity, fracture density, temperature, pressure, and rock interface parameters are calibrated to form a full-space initial model of the fracturing area. In Unit 7, after the fracturing hole drilling is completed, the borehole pulse current transmitter is powered by pulses, and the electromagnetic signal sensor acquires the current field, electromagnetic field, and ion diffusion field data of the area before fracturing. The finite element method is used to solve the multi-field coupling equations and generate a multi-physics response database before fracturing. The eighth unit requires the use of spatial filtering techniques to measure and calculate the potential difference between adjacent sensors to eliminate common-mode noise. The ninth unit uses the current field, electromagnetic field, and ion diffusion field data obtained from the multiphysics response database before fracturing to revise the initial model and obtain an optimized model suitable for the current construction environment, providing a guiding basis for the fracturing process and the monitoring of the entire space monitoring area. Unit 10: During the fracturing process, the borehole pulse current transmitter is powered by pulses. As the rock fractures develop and expand, the fracturing fluid migrates, causing changes in the regional current field, electromagnetic field, and ion diffusion field. Electromagnetic signal sensors in the full-space monitoring area acquire the change data and perform real-time moving imaging analysis on the data to form the spatial characteristics of the fracturing fluid expansion path and fracture distribution in the full space, and generate a multi-physics response database during the fracturing process. Unit 11: Extracting the spatial characteristics of fracture distribution to invert the distribution morphology of hydraulically pressure-induced fracture networks; Unit 12, combining the pressure-flow rate curves of the fracturing fluid injection during the fracturing process, marks the various stages of fracture propagation, including the initiation stage, the extension stage, and the branching stage. Unit 13, which utilizes spatial characteristics to invert the distribution morphology of hydraulically pressure-induced fracture networks, specifically includes: By calculating the unit gradient vector field, the direction of the maximum gradient is extracted as the main extension direction of the crack. Secondary gradient extrema are identified through tensor analysis, serving as crack branches; The crack length is determined by the distance the resistivity anomaly region extends along the main gradient; Estimate fracture width based on the relationship between resistivity variation and fracturing fluid conductivity; The complexity of the sewing mesh is quantitatively evaluated by using the fractal dimension of the resistivity anomaly region. Unit Fourteen involves historically accumulating the multiphysics response database before fracturing and the multiphysics response database during fracturing to provide historical reference data for new detection areas. Unit 15 involves calibrating and storing the optimized models against the current construction environment to form a database of preferred models, providing optional construction monitoring models for other detection areas. The fourth module verifies the fabric spreading morphology of the sewn mesh. The verification methods include: By comparing the consistency between the propagation rate of the resistivity anomaly zone and the pumping rate, fracturing fluid front tracking is performed. The consistency error between the propagation rate of the resistivity anomaly zone and the pumping rate should be <5%. When the error exceeds 5%, the source of the error needs to be checked and supplementary verification measures need to be taken. Unit 16, Checking the Sources of Error: Checking the accuracy and sampling frequency of the electromagnetic signal monitoring equipment, and checking the calibration of the pump flow meter and pressure sensor; Unit 17 employs supplementary verification methods: microseismic monitoring technology is used to analyze the spatiotemporal distribution of microseismic events related to fracture development and propagation, determining whether the propagation direction of microseismic events matches the electromagnetic anomaly zone; tracer flowback analysis is used to monitor the peak time of tracer concentration in the flowback fluid after fracturing, estimating the fracturing fluid migration velocity; and pump stop pressure analysis is used to invert the fracture closure pressure and filtration characteristics through pressure drop curves after pumping is suspended. Unit 18: When the error is 5% to 10%, prioritize checking data quality and equipment calibration, supplemented by tracer verification. When the error is 10% to 20%, multiple supplementary methods should be used for cross-validation. When the error exceeds 20%, operations are suspended, and geological-engineering collaborative analysis and dynamic testing are conducted to re-evaluate the fracturing plan.

12. A computer-readable storage medium storing executable instructions for a near-field monitoring system for the distribution morphology of hydraulically fractured networks as described in claim 11, characterized in that... When executed, the instruction enables the near-field monitoring method for the distribution morphology of hydraulically fractured networks as described in any one of claims 1-10.

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