Method and system for intensifying gas extraction through intelligent and accurate regulation and control and multi-method collaborative fracturing

Abstract

The invention discloses an intelligent and accurate regulation and control multi-method collaborative fracturing intensified gas extraction method and system, and the method achieves the dynamic and accurate adjustment of parameters such as borehole arrangement, hydraulic fracturing strength and ultrasonic frequency through an intelligent regulation and control algorithm based on monitoring geological parameter feedback and a parameter self-adaptive adjustment technology. The optimal gas extraction scheme can be implemented according to different coal seam geological conditions, and the accuracy and efficiency of gas extraction are remarkably improved. The coal seam anti-reflection method is simple in construction process and easy and convenient to operate, the defects of a single anti-reflection technology can be effectively overcome, the advantages and disadvantages of anti-reflection measures are complementary, the coal seam anti-reflection effect is effectively improved, efficient mining and utilization of gas resources are achieved, safe and efficient production of a mine is powerfully guaranteed, and remarkable economic benefits and social benefits are achieved.

Description

Technical Field

[0001] This application relates to the field of coal mine gas control technology, and in particular to an intelligent and precise control method and system for multi-method synergistic fracturing-enhanced gas extraction. Background Technology

[0002] Methane gas is one of the main threats to safe coal mining, and efficient methane control is crucial for ensuring safe coal mining and improving coal resource utilization. Currently, coal seam permeability enhancement technology is a key means of methane control; however, most existing permeability enhancement methods have limitations.

[0003] Traditional single permeability enhancement technologies have poor geological adaptability. Coal seam geological structures are complex and variable, with significant differences in parameters such as the degree of fracture development, stress distribution, and coal body stability in different regions. However, existing technologies operate with fixed construction parameters, failing to make timely adjustments based on dynamic changes in coal seam geological conditions. Furthermore, there is a lack of coordinated control when multiple methods are used in combination. As coal seam mining depth increases and gas drainage becomes more difficult, the combined application of multiple methods is becoming a trend, but existing technologies lack effective parameter matching mechanisms. Current technologies also suffer from lag in control. Currently, gas drainage parameter adjustments rely heavily on manual experience, from collecting coal seam geological parameters (such as gas pressure, permeability, and fracture development) on-site, to technicians analyzing the data and making adjustment decisions, and finally to actual construction parameter changes. However, coal seam geological conditions are constantly changing; parameters such as gas pressure and stress change during coal seam permeability enhancement and gas drainage. This makes it impossible to respond promptly to dynamic changes in coal seam conditions, hindering dynamic and precise control and gas drainage.

[0004] In summary, the shortcomings of traditional single-method gas drainage and permeability enhancement technologies in terms of geological adaptability, multi-method synergistic control, and timeliness of regulation have become bottlenecks restricting efficient gas drainage and safe production in coal mines. Innovative technologies are urgently needed to solve these technical challenges and achieve precise, efficient, and intelligent gas drainage. Summary of the Invention

[0005] This application provides an intelligent and precise control method and system for multi-method synergistic fracturing-enhanced gas extraction, achieving synergistic efficiency and intelligent and precise control of multiple methods, overcoming the limitations of single technologies.

[0006] To achieve the above objectives, the technical solution of this invention is as follows:

[0007] In a first aspect, embodiments of the present invention provide an intelligent and precise control method for multi-method synergistic fracturing and enhanced gas extraction, comprising: deploying an intelligent and precise control system in the coal seam extraction area, and collecting coal seam geological parameters in real time through the sensor group of the intelligent and precise control system; the geological parameters include coal seam stress, strain, formation permeability, degree of fracture development, gas concentration, flow rate, negative pressure and temperature parameters.

[0008] Based on the preset intelligent control algorithm, big data analysis and BP neural network algorithm are used to process and analyze geological parameters to determine the multi-method synergistic fracturing construction parameters;

[0009] Based on the multi-method synergistic fracturing construction parameters, synergistic permeability enhancement integrated equipment is used to construct synergistic permeability enhancement boreholes in the coal seam;

[0010] Once the synergistic permeability enhancement borehole reaches the designed position, the coal body on the borehole wall is cut by the high-pressure water jet device of the synergistic permeability enhancement integrated equipment according to the multi-method synergistic fracturing construction parameters. After the cutting is completed, the borehole is sealed by a special sealing device, and hydraulic fracturing is carried out using hydraulic fracturing equipment to form the main fracture channel in the coal seam.

[0011] After hydraulic fracturing is completed, the ultrasonic transmitting device of the integrated permeability enhancement equipment is activated. Ultrasonic waves are transmitted to the coal body through the ultrasonic transducer rod using water as a medium. Ultrasonic excitation permeability enhancement is performed in a backward segmented manner.

[0012] After the synergistic permeability enhancement is completed, gas extraction is carried out by connecting to the extraction pipeline. The gas extraction parameters are monitored in real time through the intelligent precision control system, and a comprehensive evaluation index system for the gas extraction effect is established. If the expected extraction effect is not achieved, the intelligent control algorithm is restarted to optimize the multi-method synergistic fracturing construction parameters to form a closed-loop control.

[0013] In some possible implementations, the sensor group includes a fiber optic stress sensor, an acoustic sensor, a microseismic monitor, and a gas drainage comprehensive parameter measuring instrument; wherein, the fiber optic stress sensor is used to collect coal seam stress and strain; the acoustic sensor is used to assess coal seam permeability; the microseismic monitor is used to monitor crack propagation; and the gas drainage comprehensive parameter measuring instrument is used to collect gas concentration, flow rate, negative pressure, and temperature.

[0014] In some possible implementations, the intelligent precision control system also includes a signal acquisition system, which includes switches, underground substations, core switches, and remote service controllers, used to transmit coal seam geological parameters to the ground intelligent monitoring and control center of the intelligent precision control system in real time.

[0015] In some possible implementations, multiple methods are used to coordinate fracturing parameters, including borehole layout parameters, hydraulic parameters, and ultrasonic frequency and power parameters; borehole layout parameters include borehole depth, angle, and spacing; hydraulic parameters include water pressure, flow rate, and fracturing time.

[0016] In some possible implementations, when the high-pressure water jet device is activated, the drilling rig of the integrated permeability enhancement equipment remains in a rotating state; the hydraulic fracturing equipment implements directional hydraulic fracturing through a hydraulic guide channel to form the main fracture channel.

[0017] In some possible implementations, the ultrasonic transmitting device includes an ultrasonic transmitter and a low-loss ultrasonic excitation cable. The ultrasonic transmitter is connected to an ultrasonic transducer rod via the low-loss ultrasonic excitation cable. The ultrasonic transducer rod has multiple transducers connected in series, and the coal body is segmented through backward segmented ultrasonic excitation for enhanced transparency.

[0018] Secondly, embodiments of the present invention provide an intelligent and precise control system for multi-method synergistic fracturing enhanced gas extraction, which includes a synergistic permeability enhancement integrated device and an intelligent and precise control system for performing the method of the first aspect.

[0019] The integrated permeability enhancement equipment includes a drilling rig, a high-pressure water jet device, hydraulic fracturing equipment, an ultrasonic transmitting device, and a sealing device. The drilling rig is used to construct permeability enhancement boreholes in the coal seam. The high-pressure water jet device is used to cut the coal body in the borehole wall of the permeability enhancement borehole. The hydraulic fracturing equipment is used to perform hydraulic fracturing after sealing to form the main fracture channel. The ultrasonic transmitting device includes an ultrasonic transmitter and an ultrasonic transducer. The ultrasonic transmitter is connected to the ultrasonic transducer via a low-loss ultrasonic excitation cable. The ultrasonic transducer is used to transmit ultrasonic waves to the coal body using water as a medium, and adopts a backward segmented ultrasonic excitation.

[0020] The intelligent precision control system includes a sensor array, a signal acquisition and transmission module, and a ground-based intelligent monitoring and control center. The sensor array includes fiber optic stress sensors, acoustic sensors, microseismic monitors, and a comprehensive gas drainage parameter measuring instrument, used to collect data on coal seam stress, strain, permeability, crack propagation, and gas concentration, flow rate, negative pressure, and temperature. The signal acquisition and transmission module is a 485 signal acquisition system used to transmit the parameters collected by the sensor array to the ground-based intelligent monitoring and control center. The ground-based intelligent monitoring and control center is equipped with a big data analysis module and an artificial intelligence BP neural network algorithm module, used to process and analyze the collected parameters to determine construction parameters, and to optimize and adjust the parameters based on the drainage effect evaluation results, forming a closed-loop control.

[0021] In some possible implementations, the 485 signal acquisition system includes a switch, a downhole substation, a core switch, and a remote service controller connected in sequence. The switch is connected to the sensor group, and the remote service controller is communicatively connected to the ground intelligent monitoring and control center.

[0022] One or more technical solutions provided in the embodiments of the present invention have at least the following technical effects or advantages:

[0023] In this embodiment of the invention, an intelligent control algorithm based on monitoring geological parameter feedback and parameter adaptive adjustment technology are used to achieve dynamic and precise adjustment of parameters such as borehole layout, hydraulic fracturing intensity, and ultrasonic frequency. This enables the implementation of optimal gas extraction schemes according to different coal seam geological conditions, significantly improving the accuracy and efficiency of gas extraction. By using multiple methods to synergistically enhance the permeability of the coal seam, the construction process is simple and easy to operate. It effectively solves the shortcomings of single permeability enhancement technologies, with complementary advantages and disadvantages of each enhancement measure, effectively improving the permeability of the coal seam and achieving efficient mining and utilization of gas resources. This strongly guarantees the safe and efficient production of the mine, resulting in significant economic and social benefits. Attached Figure Description

[0024] To more clearly illustrate the embodiments of the present invention, the accompanying drawings used in the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 A schematic flowchart of an embodiment of an intelligent and precise multi-method synergistic fracturing enhanced gas extraction method provided for the implementation of the present invention;

[0026] Figure 2 This is a schematic diagram of the BP neural network algorithm in an embodiment of the present invention;

[0027] Figure 3 A schematic diagram of the principle of the intelligent and precise control method for multi-method synergistic fracturing and enhanced gas extraction in coal seams provided in this embodiment of the invention;

[0028] Figure 4 This is a schematic diagram of the water jet permeability enhancement principle in coal seams according to an embodiment of the present invention;

[0029] Figure 5 This is a schematic diagram illustrating the principle of water jetting and hydraulic fracturing for enhancing the permeability of coal seams in an embodiment of the present invention.

[0030] Figure 6 This is a schematic diagram of the logical structure of the intelligent and precise multi-method synergistic fracturing enhanced gas extraction method in an embodiment of the present invention;

[0031] Figure 7 This is a schematic diagram of the structure of an intelligent and precise multi-method synergistic fracturing enhanced gas extraction system according to an embodiment of the present invention. Detailed Implementation

[0032] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0033] In the relevant descriptions of this embodiment, the terms "including," "containing," and "possessing" are all open terms and are generally understood to include but not be limited to; the term "at least one" is generally understood to mean one or more, where "multiple" refers to two or more; the term "at least one of the following" or similar expressions refer to any combination of these items, including any combination of single or multiple items, for example, "at least one of a, b, or c", or "at least one of a, b, and c", which can all mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple; the symbol "A / B" is used to describe the selection relationship of associated objects, generally indicating an "or" relationship.

[0034] In the following description of the embodiments, the terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The singular forms "a" and "the" as used in the embodiments of this application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0035] Those skilled in the art should understand that, in the following description of the embodiments of this application, the sequence of numbers does not imply the order of execution. Some or all steps may be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0036] Those skilled in the art will understand that the numerical ranges in the embodiments of this application should be understood to specifically disclose each intermediate value between the upper and lower limits of the range. Any stated value or intermediate value within a stated range, as well as any other stated value or each smaller range between intermediate values ​​within a range, are also included within this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0037] Unless otherwise stated, the technical / scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. While this application describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this application. All references to this specification are incorporated by way of citation to disclose and describe the methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0038] To illustrate the technical solution of the present invention, specific embodiments are described below.

[0039] Methane gas is one of the main threats to safe coal mining, and efficient methane control is crucial for ensuring safe coal mining and improving coal resource utilization. Currently, coal seam permeability enhancement technology is a key means of methane control; however, most existing permeability enhancement methods have limitations.

[0040] Traditional gas drainage and permeability enhancement technologies lack real-time monitoring and dynamic control mechanisms for coal seam geological conditions. This makes it difficult to precisely adjust drilling, hydraulic fracturing, and ultrasonic excitation parameters based on factors such as gas pressure, permeability, and fracture development in different coal seams. This results in unstable permeability enhancement effects, low gas drainage efficiency, and high treatment costs. While hydraulic fracturing alone can create gas diversion channels, the fracturing water entering these channels creates a water-locking effect, blocking micro-fractures and hindering gas desorption and seepage. Although ultrasonic excitation technology can improve the microstructure of the coal seam, the propagation distance and influence range of ultrasonic waves within the coal medium are limited. Existing gas drainage equipment is functionally limited and complex to operate, lacking an integrated design that combines hydraulic permeability enhancement, ultrasonic emission, and real-time monitoring. This leads to high construction difficulty, poor equipment synergy, and difficulty in meeting the requirements for safe and efficient coal mine production.

[0041] Coal seam geological structures are complex and variable, with significant differences in parameters such as the degree of fracture development, stress distribution, and coal body stability across different regions. However, current technologies rely on fixed construction parameters, failing to adapt to dynamic changes in coal seam geological conditions. Furthermore, collaborative control is lacking when multiple methods are used in combination. As coal seam mining depth increases and gas drainage becomes more challenging, the combined application of multiple methods is becoming increasingly common, but current technologies lack effective parameter matching mechanisms. Existing technologies also exhibit lag in control measures. Currently, gas drainage parameter adjustments primarily rely on manual experience, from collecting coal seam geological parameters (such as gas pressure, permeability, and fracture development) on-site, to technicians analyzing the data and making adjustment decisions, and finally to actual construction parameter changes. However, coal seam geological conditions are constantly changing; parameters such as gas pressure and stress change during permeability enhancement and gas drainage. This inability to respond promptly to dynamic changes in coal seam conditions hinders dynamic and precise control and gas drainage.

[0042] In summary, the shortcomings of traditional single-method gas drainage and permeability enhancement technologies in terms of geological adaptability, multi-method synergistic control, and timeliness of regulation have become bottlenecks restricting efficient gas drainage and safe production in coal mines. Innovative technologies are urgently needed to solve these technical challenges and achieve precise, efficient, and intelligent gas drainage.

[0043] Based on this, embodiments of the present invention provide a method and system for intelligent and precise control of multi-method synergistic fracturing enhanced gas extraction, achieving synergistic efficiency enhancement of multiple methods and intelligent and precise control, overcoming the limitations of single technologies.

[0044] Figure 1 A schematic flowchart illustrating an embodiment of the intelligent and precise multi-method synergistic fracturing-enhanced gas extraction method provided for the implementation of this invention is shown below. Figure 1 As shown, the above method may include:

[0045] S101, an intelligent and precise control system is deployed in the coal seam extraction area. The sensor group of the intelligent and precise control system collects the geological parameters of the coal seam in real time.

[0046] Among them, geological parameters may include coal seam stress, strain, formation permeability, degree of fracture development, gas concentration, flow rate, negative pressure and temperature parameters.

[0047] In some embodiments, the sensor group includes a fiber optic stress sensor, an acoustic sensor, a micro-vibration monitor, and a gas drainage integrated parameter measuring instrument.

[0048] Among them, the fiber optic stress sensor can be installed by embedding it into the borehole wall to collect coal seam stress and strain in real time; the acoustic sensor uses the propagation characteristics of acoustic waves, such as velocity and attenuation, to assess coal seam permeability; the microseismic monitor can capture coal fracture events, thereby quantifying fracture density and propagation direction, and is used to monitor coal crack propagation in real time; and the gas drainage comprehensive parameter measuring instrument is used to collect gas concentration, flow rate, negative pressure, and temperature.

[0049] In some embodiments, the intelligent precision control system further includes a signal acquisition system, which includes a switch, an underground substation, a core switch, and a remote service controller. The signal acquisition system is used to transmit the acquired coal seam geological parameters to the ground intelligent monitoring and control center of the intelligent precision control system in real time, so that the control center can process and apply the coal seam geological parameters.

[0050] For example, a signal acquisition system can be a RS-485 signal acquisition system. A RS-485 signal acquisition system is an industrial data acquisition solution based on the RS-485 communication protocol. It converts physical quantities into electrical signals through sensors, then converts these signals into differential levels via an RS-485 converter. Utilizing a bus network with strong anti-interference capabilities and long transmission distances, it enables reliable communication between the main controller and multiple node devices. It supports standardized protocols such as MODBUS and features low cost, simple wiring, and strong compatibility.

[0051] S102, based on a preset intelligent control algorithm, uses big data analysis and BP neural network algorithm to process and analyze geological parameters to determine multi-method collaborative fracturing construction parameters;

[0052] The preset intelligent control algorithm can be a composite system that integrates multi-dimensional parameter analysis, dynamic decision generation, and closed-loop feedback optimization. For example, it can use principal component analysis for dimensionality reduction, BP neural network decision-making, NSGA-II genetic algorithm optimization, and other technologies, combined with geomechanical constraints and expert rules, to achieve real-time matching of geological parameters and construction parameters. It can dynamically adjust hydraulic fracturing and ultrasonic parameters based on coal seam monitoring data, and has self-iterative capabilities to ensure optimal synergistic fracturing effect while maintaining safety and controllability.

[0053] For example, Figure 2 This is a schematic diagram of the BP neural network algorithm in an embodiment of the present invention. See also... Figure 2 As shown, when processing and analyzing geological parameters, the first step is to design the network structure. This involves constructing a network structure as follows: Figure 2 The diagram shows a three-level neural network architecture comprising an input layer, a hidden layer, and an output layer. The input layer contains four neurons, corresponding to parameters acquired by the four parameter acquisition devices in the aforementioned sensor group: a fiber optic stress sensor, an acoustic sensor, a microseismic monitor, and a gas drainage integrated parameter measuring instrument. The hidden layer contains eight neurons, which can use the ReLU activation function to handle nonlinear features and L2 regularization to suppress overfitting. The output layer outputs the multi-method collaborative fracturing parameters needed in subsequent construction processes.

[0054] In some embodiments, the multi-method coordinated fracturing parameters include borehole layout parameters, hydraulic parameters, and ultrasonic frequency and power parameters; the borehole layout parameters include borehole depth, angle, and spacing; the hydraulic parameters include water pressure, flow rate, and fracturing time.

[0055] In this embodiment of the invention, the BP neural network algorithm can perform in-depth analysis of real-time collected geological parameters such as coal seam permeability, fracture density, and gas pressure. The neural network takes key geological parameters as input and dynamically outputs the synergistic parameters of hydraulic fracturing and ultrasound after multi-layer neuron processing. For example, when low coal seam permeability and insufficient fracture density are detected, the network automatically triggers the main fracture construction optimization logic, forming more main fracture channels by increasing the fracturing intensity, while increasing the ultrasound energy to enhance penetration and assist fracture expansion. When the fracture density exceeds the preset value and preliminary connection is detected, the neural network switches to the microfracture refinement mode, appropriately reducing the fracturing intensity to avoid disordered expansion, simultaneously increasing the ultrasound frequency and reducing the action step, and using refined perturbation to activate the opening and connection of micropores, realizing the synergistic development of the main fracture and microfracture networks, and significantly improving the coal seam permeability.

[0056] S103, based on the multi-method synergistic fracturing construction parameters, uses an integrated synergistic permeability enhancement equipment to construct synergistic permeability enhancement boreholes in the coal seam;

[0057] Specifically, after determining the multi-method synergistic fracturing construction parameters according to step S102, the construction process is initiated through the modular control system of the integrated synergistic permeability enhancement equipment, and synergistic permeability enhancement boreholes are precisely constructed in the designated area of ​​the coal seam.

[0058] For example, firstly, based on the coal seam occurrence characteristics and parameters, the drilling location is selected in the return airway or bottom drainage roadway, and the coordinates of the drilling point are calibrated through the equipment positioning system; then, the drilling mechanism of the integrated permeability enhancement equipment is debugged, the appropriate drill bit is installed according to the drilling diameter parameters, and the drilling rig's advance speed and rotation speed are set; during drilling, the real-time dynamic monitoring module on the equipment continuously provides feedback on the drilling trajectory. If the detected angle deviation exceeds the safety value, the advance mechanism is automatically triggered for fine-tuning to ensure that the borehole extends at the designed angle; when drilling reaches the preset depth node, drilling is paused, and the integrity of the borehole wall is checked through the integrated sonic logging device. After confirming that there is no serious borehole collapse, construction continues; finally, when the drilling depth reaches the design value, drilling is stopped, completing the construction of the integrated permeability enhancement borehole, laying a precise duct foundation for subsequent high-pressure water jet cutting, hydraulic fracturing, and ultrasonic excitation processes.

[0059] S104. After the synergistic permeability enhancement borehole reaches the design position, according to the multi-method synergistic fracturing construction parameters, the high-pressure water jet device of the synergistic permeability enhancement integrated equipment is used to cut the coal body on the borehole wall. After the cutting is completed, the borehole is sealed by a special sealing device, and hydraulic fracturing is carried out using hydraulic fracturing equipment to form the main fracture channel in the coal seam.

[0060] In some embodiments, when the high-pressure water jet device is activated, the drilling rig of the integrated anti-permeability device remains in a rotating state; the hydraulic fracturing device performs directional hydraulic fracturing through the hydraulic guide channel to form the main fracture channel.

[0061] Specifically, after the borehole reaches the designed depth and the final borehole position is confirmed to meet the requirements, the integrated permeability enhancement equipment automatically switches to the operating mode. First, the high-pressure water jet device is activated. Based on preset water jet parameters, high-pressure water is delivered through the drill rod's built-in channel, while the drill rig rotates to allow the drill bit to circumferentially cut the coal seam in the borehole wall, forming an annular guide groove. This provides a directional fracture propagation path for subsequent hydraulic fracturing. During the cutting process, the pressure fluctuations of the water jet are monitored in real time by an integrated pressure sensor. After cutting, the high-pressure water jet device is withdrawn, and a dedicated sealing device is used to seal the borehole. The distance between the sealing device and the borehole opening can be determined based on monitored geological parameters. Then, high-pressure sealing fluid is injected, causing the sealing device to expand and tightly adhere to the borehole wall, forming a reliable sealing section to isolate fluids inside and outside the borehole.

[0062] After the borehole is sealed, the hydraulic fracturing equipment can be connected to the fracturing channel inside the borehole through a dedicated pipeline to carry out staged hydraulic fracturing according to preset parameters.

[0063] For example, in the initial stage, hydraulic fracturing is initiated with water pressure at 0.6 times the uniaxial compressive strength of the coal seam. After each stage of increasing the pressure, the pressure is stabilized for a few minutes, and the fracture propagation signal is recorded simultaneously by a microseismic monitoring instrument. When the fracturing flow rate steadily increases to more than 1.5 times the initial value and the acoustic sensor detects a wave velocity decrease of ≥15%, the pressure holding stage is entered and continues for a period of time, eventually forming a main fracture network channel centered on the borehole in the coal seam.

[0064] S105 After hydraulic fracturing is completed, the ultrasonic transmitting device of the integrated permeability enhancement equipment is activated. Ultrasonic waves are transmitted to the coal body through the ultrasonic transducer rod using water as a medium. Ultrasonic excitation permeability enhancement is performed in a backward segmented manner.

[0065] In some embodiments, the ultrasonic transmitting device includes an ultrasonic transmitter and a low-loss ultrasonic excitation cable. The ultrasonic transmitter is connected to an ultrasonic transducer rod via the low-loss ultrasonic excitation cable. The ultrasonic transducer rod has multiple transducers connected in series, and the coal body is segmented through a backward segmented ultrasonic excitation enhancement method.

[0066] In some embodiments, the completion of hydraulic fracturing can be determined by the stable return of the fracturing system pressure to the initial level and a significant reduction in the frequency of microseismic events. After hydraulic fracturing is completed, the integrated anti-permeability device can automatically switch to ultrasonic excitation mode and activate the ultrasonic transmitter to perform anti-permeability operations.

[0067] For example, firstly, the state of the residual water medium in the borehole is confirmed to ensure that the water medium covers the working section of the transducer rod. Then, a signal connection is established between the ground ultrasonic transmitter and the ultrasonic transducer rod in the borehole through a low-loss ultrasonic excitation cable. The ultrasonic transducer rod is connected in series with multiple high-frequency transducers to ensure efficient energy transmission. Based on the ultrasonic parameters determined in step S102, the initial excitation parameters are set in combination with the real-time geological conditions of the coal seam.

[0068] Subsequently, a segmented excitation process with backward movement was adopted. The ultrasonic transducer was initially placed at a predetermined position deep within the borehole. The transmitting device was activated to continuously excite the current section of coal seam for a predetermined duration. Utilizing the vibration, thermal, and cavitation effects of ultrasound, the residual water-locking effect from hydraulic fracturing was unlocked, promoting the opening of microfractures. After a single excitation segment, the transducer was controlled by the equipment propulsion mechanism to retreat at a set backward step distance. The backward step distance was adjusted according to the coal seam's firmness. The excitation process was paused and repeated after each backward step. During the retreat, the transducer was kept in good contact with the borehole wall to ensure effective energy transfer. Throughout the process, the wave velocity changes in the coal seam were monitored in real time by an acoustic sensor. The effective expansion of microfractures was determined by the wave velocity changes. If the excitation effect of a certain segment did not meet expectations, the power of that segment was appropriately increased and the excitation time was extended. Finally, through segmented excitation with backward movement, a through channel was formed in the coal seam, with the main fracture as the framework and the microfractures as the network.

[0069] In this embodiment of the invention, hydraulic permeability enhancement, ultrasonic emission, and monitoring functions are integrated into a modular device and rapidly assembled and maintained through standardized interfaces, significantly improving the efficiency and adaptability of coal mine gas extraction operations. The modular design allows for pre-assembly and debugging of each functional module on the ground, with seamless integration between modules achieved on-site through standardized interfaces, shortening the equipment deployment time in the early stages of construction. During operation, each functional module achieves real-time data and power interaction through standardized interfaces: the pressure and flow parameters of the hydraulic permeability enhancement module can be directly fed back to the monitoring module via the interface; the coal seam stress and fracture development data collected by the monitoring module are synchronously transmitted to the ultrasonic emission module for dynamic parameter adjustment, forming a closed-loop collaboration of "permeability enhancement-monitoring-control," avoiding parameter mismatch problems caused by communication delays or poor coordination in traditional equipment, and significantly enhancing the stability of the permeability enhancement effect.

[0070] S106, after the synergistic permeability enhancement is completed, gas extraction is carried out by connecting to the extraction pipeline. The gas extraction parameters are monitored in real time through the intelligent precision control system, and a comprehensive evaluation index system for the gas extraction effect is established. If the expected extraction effect is not achieved, the intelligent control algorithm is restarted to optimize the multi-method synergistic fracturing construction parameters to form a closed-loop control.

[0071] Specifically, after the synergistic permeability enhancement is completed, the extraction pipeline can be connected to the outlet of the synergistic permeability enhancement borehole through a dedicated sealing joint, and then connected to the mine extraction system for gas extraction operations. Simultaneously, an intelligent precision control system can be activated to dynamically monitor the entire gas extraction process. The gas extraction comprehensive parameter measuring instrument collects core parameters such as gas concentration, flow rate, negative pressure, and coal temperature in the extraction pipeline in real time. Combined with data on coal seam stress changes and fracture stability fed back by fiber optic stress sensors and acoustic sensors, all monitoring data are transmitted in real time to the ground-based intelligent monitoring and control center via a signal acquisition system, forming a dynamic monitoring curve of the extraction parameters.

[0072] In some embodiments, to scientifically evaluate the permeability enhancement effect, a multi-dimensional comprehensive evaluation index system for gas extraction effect can be established, specifically including: extraction concentration compliance rate, flow stability coefficient, and gas desorption rate, etc. The comprehensive evaluation model built into the intelligent control system can be used to weight and score each index, generating a quantitative effect evaluation report.

[0073] In some embodiments, if the evaluation results show that the expected extraction effect is not achieved, the system can automatically trigger a closed-loop optimization mechanism: the ground intelligent monitoring and control center can call the big data analysis module to compare and analyze historical and real-time data, and combine the specific indicators that are not up to standard. The system can then use the BP neural network algorithm to reverse-engineer the parameter adjustment direction and re-optimize the borehole layout, hydraulic and ultrasonic collaborative parameters. After the optimized parameters are verified for safety, they are sent to the field to guide the integrated permeability enhancement equipment to carry out targeted permeability enhancement operations, forming a closed-loop control process of "extraction-monitoring-evaluation-optimization-re-permeability enhancement", continuously improving the efficiency and stability of gas extraction, and ensuring that the final extraction effect meets the needs of mine safety production and resource utilization.

[0074] The following specific embodiment illustrates the intelligent and precise multi-method synergistic fracturing enhanced gas extraction method provided by the present invention.

[0075] For example, see Figures 3 to 5 As shown, where, Figure 3 A schematic diagram of the principle of the intelligent and precise control method for multi-method synergistic fracturing and enhanced gas extraction in coal seams provided in this embodiment of the invention; Figure 4 This is a schematic diagram of the water jet permeability enhancement principle in coal seams according to an embodiment of the present invention; Figure 5 This is a schematic diagram of the principle of water jetting and hydraulic fracturing to enhance the permeability of coal seams in an embodiment of the present invention.

[0076] Among them, 1 is the coal seam, 2 is the integrated equipment for synergistic permeability enhancement, 3 is the ultrasonic transmitter, 4 is the ultrasonic transducer rod, 5 is the synergistic permeability enhancement borehole, 6 is the special sealing device, 7 is the intelligent precision control system, 8 is the gas drainage comprehensive parameter measuring instrument, 9 is the 485 signal acquisition system, 10 is the drainage hole, 11 is the drainage pipeline, 12 is the high-pressure hydraulic guide channel, 13 is the hydraulic fracturing fracture, 14 is the ultrasonic dredging fracture, 15 is the working face, 16 is the intake airway, and 17 is the return airway.

[0077] Figure 6 This is a schematic diagram of the logical structure of the intelligent and precise control method for multi-method synergistic fracturing and enhanced gas extraction in an embodiment of the present invention. Combined with... Figures 3 to 5 The coal seam fracturing principle illustrated in this embodiment of the invention utilizes an intelligent monitoring and control system. Various sensors are deployed in the coal seam gas extraction area to collect real-time coal seam geological parameters, including: an intelligent precision control system 7 measuring coal seam stress and strain using a fiber optic stress sensor 7-1; an acoustic sensor 7-2 indirectly assessing formation permeability based on acoustic wave propagation characteristics (such as velocity and attenuation); a microseismic monitor 7-3 evaluating parameters such as the degree of fracture development; and a comprehensive gas extraction parameter measuring instrument 8 measuring borehole gas concentration, flow rate, negative pressure, and temperature. The collected geological parameters are transmitted in real-time to the central processing unit of the intelligent monitoring and control system on the ground via a 485 signal acquisition system 9.

[0078] After receiving data from sensors, the central processing unit performs in-depth analysis of the data using big data analytics and a backpropagation (BP) neural network algorithm based on a pre-defined intelligent control algorithm. According to the analysis results, it dynamically adjusts borehole layout parameters (such as borehole depth, angle, and spacing), hydraulic parameters (such as water pressure, flow rate, and fracturing time), and ultrasonic frequency and power. For example, when a region is found to have low coal permeability and high gas pressure, the intelligent control algorithm automatically increases the hydraulic fracturing intensity in that region and adjusts the ultrasonic frequency to more effectively improve the microstructure of the coal seam.

[0079] Based on the adjusted parameters, a combined hydraulic and ultrasonic permeability enhancement process was implemented. First, the integrated permeability enhancement device 2 is used to construct the return airway 17 of coal seam 1. According to the parameter design, the integrated permeability enhancement device 2 is used for drilling. When the borehole reaches the design position, the drilling rig is kept rotating. The high-pressure water pump is started, and the high-pressure water jet cuts the coal body of the borehole wall. After the high-pressure water jet cuts the coal body of the borehole wall, the hole is sealed by the plugger 6. The hydraulic measures equipment forms the main fracture channel in the coal seam, creating an extraction path for gas flow. After the hydraulic measures are completed, the ultrasonic transmitter 3 is started. The signal is transmitted to the ultrasonic transducer 4 using a low-loss ultrasonic excitation cable. The ultrasonic transmitter uses water as a medium to propagate the ultrasonic waves into the coal body. The ultrasonic excitation is performed in a backward segmented manner. The vibration effect, thermal effect and cavitation effect of the ultrasonic waves are used to accurately improve the micropore / fracture network of the coal body, unblock the water-locking effect caused by the hydraulic measures, and promote the further expansion and connection of coal body fractures, significantly improving the permeability of the coal seam and the gas desorption and seepage efficiency.

[0080] After the synergistic permeability enhancement is completed, gas extraction is carried out through extraction pipeline 11. An intelligent monitoring and control system is used to monitor the gas extraction effect in real time, collecting data such as gas extraction flow rate and concentration. The permeability enhancement effect is evaluated, and a comprehensive evaluation index system for precise gas extraction is established. If the expected effect is not achieved, the intelligent control algorithm is restarted to optimize and adjust relevant parameters, forming a closed-loop control system to achieve intelligent and precise control of multi-method synergistic fracturing-enhanced gas extraction.

[0081] In this embodiment of the invention, by deeply integrating geological parameter monitoring, intelligent algorithms, and physical permeability enhancement technology, a cross-domain innovation system is constructed, forming an intelligent control system driven by geological parameters, a dynamic parameter optimization mechanism for hydraulic-ultrasonic synergy, and a modular equipment innovation scheme. This system specifically addresses key issues in existing technologies such as poor geological adaptability, inability to dynamically match coal seam conditions, low synergistic efficiency, and complex equipment operation. Based on intelligent control algorithms and parameter adaptive adjustment technology using feedback from monitored geological parameters, it achieves dynamic and precise adjustment of core parameters such as borehole layout, hydraulic fracturing intensity, and ultrasonic frequency. It can optimize extraction schemes in real time according to geological conditions such as stress distribution, fracture development, and permeability of different coal seams. Through a synergistic permeability enhancement process that forms main fracture channels through hydraulic measures and refines micro-fracture networks through ultrasonic excitation, it achieves complementary advantages of "main fracture construction - micro-fracture connection - water-locking effect unblocking," effectively overcoming the limitations of single permeability enhancement technologies. Simultaneously, it integrates hydraulic permeability enhancement, ultrasonic emission, and real-time monitoring functions into modular equipment, enabling rapid assembly and maintenance through standardized interfaces, simplifying construction processes and improving operational convenience. This significantly improves the accuracy and efficiency of gas extraction, ensures safe production in the mine, and enables the efficient exploitation and utilization of gas resources.

[0082] Based on the same inventive concept, this application also provides an intelligent and precise control system for multi-method synergistic fracturing enhanced gas extraction, used to execute the above-mentioned intelligent and precise control system for multi-method synergistic fracturing enhanced gas extraction. Figure 7 This is a schematic diagram of a smart and precise multi-method synergistic fracturing enhanced gas extraction system according to an embodiment of the present invention. In the diagram, 7-1 is a fiber optic stress sensor, 7-2 is an acoustic sensor, and 7-3 is a micro-vibration monitor; 8-1 is a temperature sensor, 8-2 is a flow sensor, 8-3 is a concentration sensor, and 8-4 is a negative pressure sensor; 9-1 is a switch, 9-2 is a downhole substation, 9-3 is a core switch, 9-4 is a remote service controller, and 9-5 is a back-end display platform. See also... Figure 7 As shown, the intelligent and precise control multi-method synergistic fracturing enhanced gas extraction system may include: a synergistic permeability enhancement integrated device and an intelligent and precise control system;

[0083] The integrated permeability enhancement equipment includes a drilling rig, a high-pressure water jet device, hydraulic fracturing equipment, an ultrasonic transmitter, and a sealing device. The drilling rig is used to construct permeability enhancement boreholes in coal seams. The high-pressure water jet device is used to cut the coal body in the borehole wall of the permeability enhancement borehole. The hydraulic fracturing equipment is used to perform hydraulic fracturing after sealing to form the main fracture channel. The ultrasonic transmitter includes an ultrasonic transmitter and an ultrasonic transducer rod. The ultrasonic transmitter is connected to the ultrasonic transducer rod through a low-loss ultrasonic excitation cable. The ultrasonic transducer rod is used to transmit ultrasonic waves to the coal body using water as a medium, and adopts a backward segmented ultrasonic excitation method.

[0084] The intelligent and precise control system comprises a sensor array, a signal acquisition and transmission module, and a ground-based intelligent monitoring and control center. The sensor array includes fiber optic stress sensors, acoustic sensors, microseismic monitors, and a comprehensive gas drainage parameter measuring instrument, used to collect data on coal seam stress, strain, permeability, crack propagation, and gas concentration, flow rate, negative pressure, and temperature. The signal acquisition and transmission module is a 485 signal acquisition system used to transmit the parameters collected by the sensor array to the ground-based intelligent monitoring and control center. The ground-based intelligent monitoring and control center is equipped with a big data analysis module and an artificial intelligence BP neural network algorithm module, used to process and analyze the collected parameters to determine construction parameters and optimize and adjust the parameters based on the drainage effect evaluation results, forming a closed-loop control.

[0085] In some possible implementations, the 485 signal acquisition system includes a switch, a downhole substation, a core switch, and a remote service controller connected in sequence. The switch is connected to the sensor group, and the remote service controller is communicatively connected to the ground intelligent monitoring and control center.

[0086] The various embodiments in this specification are described in a progressive manner. For the same or similar parts between the various embodiments, please refer to each other. Each embodiment focuses on describing the differences from other embodiments.

[0087] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit this application. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of this application.

Claims

1. A method for intelligent and precise control of multi-method synergistic fracturing to enhance gas extraction, characterized in that, include: An intelligent and precise control system is deployed in the coal seam extraction area, and the geological parameters of the coal seam are collected in real time through the sensor group of the intelligent and precise control system. The geological parameters include coal seam stress, strain, formation permeability, fracture development degree, gas concentration, flow rate, negative pressure, and temperature parameters. Based on the preset intelligent control algorithm, big data analysis and BP neural network algorithm are used to process and analyze the geological parameters to determine the multi-method synergistic fracturing construction parameters; Based on the multi-method synergistic fracturing construction parameters, synergistic permeability enhancement integrated equipment is used to construct synergistic permeability enhancement boreholes in the coal seam; Once the synergistic permeability enhancement borehole reaches the designed position, the coal body on the borehole wall is cut by the high-pressure water jet device of the synergistic permeability enhancement integrated equipment according to the multi-method synergistic fracturing construction parameters. After the cutting is completed, the borehole is sealed by a special sealing device, and hydraulic fracturing is carried out using hydraulic fracturing equipment to form the main fracture channel in the coal seam. After hydraulic fracturing is completed, the ultrasonic transmitting device of the integrated synergistic permeability enhancement equipment is activated. Ultrasonic waves are transmitted to the coal body through the ultrasonic transducer rod using water as a medium, and ultrasonic excitation permeability enhancement is performed in a backward segmented manner. After the synergistic permeability enhancement is completed, gas extraction is carried out by connecting to the extraction pipeline. The gas extraction parameters are monitored in real time through the intelligent precision control system, and a comprehensive evaluation index system for the gas extraction effect is established. If the expected extraction effect is not achieved, the intelligent control algorithm is restarted to optimize the multi-method synergistic fracturing construction parameters to form a closed-loop control.

2. The method according to claim 1, characterized in that, The sensor group includes a fiber optic stress sensor, an acoustic wave sensor, a micro-vibration monitor, and a gas drainage comprehensive parameter measuring instrument; wherein, the fiber optic stress sensor is used to collect coal seam stress and strain; the acoustic wave sensor is used to assess coal seam permeability; the micro-vibration monitor is used to monitor crack propagation; and the gas drainage comprehensive parameter measuring instrument is used to collect gas concentration, flow rate, negative pressure, and temperature.

3. The method according to claim 2, characterized in that, The intelligent precision control system also includes a signal acquisition system, which includes a switch, an underground substation, a core switch, and a remote service controller, used to transmit the coal seam geological parameters to the ground intelligent monitoring and control center of the intelligent precision control system in real time.

4. The method according to claim 3, characterized in that, The multi-method coordinated fracturing parameters include borehole layout parameters, hydraulic parameters, and ultrasonic frequency and power parameters; the borehole layout parameters include borehole depth, angle, and spacing; the hydraulic parameters include water pressure, flow rate, and fracturing time.

5. The method according to claim 1, characterized in that, When the high-pressure water jet device is started, the drilling rig of the integrated anti-permeability device remains in a rotating state; the hydraulic fracturing device implements directional hydraulic fracturing through the hydraulic guide channel to form the main fracture channel.

6. The method according to claim 1, characterized in that, The ultrasonic transmitting device includes an ultrasonic transmitter and a low-loss ultrasonic excitation cable. The ultrasonic transmitter is connected to the ultrasonic transducer rod through the low-loss ultrasonic excitation cable. The ultrasonic transducer rod has multiple transducers connected in series, and the coal body is segmented through the backward segmented ultrasonic excitation and penetration enhancement.

7. A smart and precise multi-method synergistic fracturing enhanced gas extraction system, used to perform the method described in any one of claims 1 to 6, characterized in that, This includes integrated anti-reflective coating equipment and intelligent precision control system; The integrated permeability enhancement equipment includes a drilling rig, a high-pressure water jet device, a hydraulic fracturing device, an ultrasonic transmitting device, and a sealing device. The drilling rig is used to construct permeability enhancement boreholes in the coal seam. The high-pressure water jet device is used to cut the coal body in the borehole wall of the permeability enhancement borehole. The hydraulic fracturing device is used to perform hydraulic fracturing after sealing the borehole to form the main fracture channel. The ultrasonic transmitting device includes an ultrasonic transmitter and an ultrasonic transducer. The ultrasonic transmitter is connected to the ultrasonic transducer via a low-loss ultrasonic excitation cable. The ultrasonic transducer is used to transmit ultrasonic waves to the coal body using water as a medium, employing a backward segmented ultrasonic excitation method. The intelligent precision control system includes a sensor group, a signal acquisition and transmission module, and a ground-based intelligent monitoring and control center. The sensor group includes a fiber optic stress sensor, an acoustic sensor, a micro-vibration monitor, and a comprehensive gas drainage parameter measuring instrument, used to collect data on coal seam stress, strain, permeability, crack propagation, and gas concentration, flow rate, negative pressure, and temperature. The signal acquisition and transmission module is a 485 signal acquisition system used to transmit the parameters collected by the sensor group to the ground-based intelligent monitoring and control center. The ground-based intelligent monitoring and control center is equipped with a big data analysis module and an artificial intelligence BP neural network algorithm module, used to process and analyze the collected parameters to determine construction parameters, and to optimize and adjust the parameters based on the drainage effect evaluation results, forming a closed-loop control.

8. The system according to claim 7, characterized in that, The 485 signal acquisition system includes a switch, a downhole substation, a core switch, and a remote service controller connected in sequence. The switch is connected to the sensor group, and the remote service controller is communicatively connected to the ground intelligent monitoring and control center.

Images