Fracturing enhanced biodegradation repair system and method for low-permeability polluted formation

Abstract

The invention provides a low-permeability polluted stratum fracturing enhanced biodegradation repair system and method, and the repair system comprises a sleeve, a hydraulic fracturing device, a biological agent injection device, a cross resistivity monitoring device, a pH driving device, a thermal resistance driving device and an online monitoring regulation and control system, wherein the hydraulic fracturing device is used for making cracks in soil to provide a channel for conveying a biological agent; the biological agent injection device is used for conveying a biological agent to the polluted soil through the crack; the cross resistivity monitoring device is used for monitoring resistivity change in real time so as to adjust the injection amount and the injection process of the biological agent; the pH driving device and the thermal resistance driving device are respectively used for changing the pH value and the temperature of the soil; the on-line monitoring regulation and control system is connected with the five devices and is used for monitoring and controlling the operation of the whole repairing system on line. The method is simple in process, environment-friendly, low in manufacturing cost, good in repairing effect and capable of achieving accurate and rapid repairing and large-scale repairing.

Description

Technical Field

[0001] The present invention belongs to the technical field of soil pollution and groundwater pollution remediation, and particularly relates to a biodegradation remediation method for low-permeability sites, and more particularly to an environment-driven fracturing enhancement and on-line monitoring and regulation remediation technology for biodegradation. Background Art

[0002] At present, there are a large number of polluted sites of various types such as industry, agriculture, and solid waste in China, and there is an urgent need for pollution site remediation and risk control. Currently, in-situ remediation methods such as chemical oxidation, multiphase extraction, and biodegradation remediation are mainly used. Among them: the chemical oxidation technology achieves the degradation of pollutants by injecting chemical agents to react with organic pollutants. However, due to the large amount of chemical agents used, it is easy to cause secondary soil pollution; multiphase extraction extracts groundwater carrying pollutants and removes pollutants through processes such as elution and adsorption. This technology has disadvantages such as complicated treatment processes, slow remediation speed, high cost, and poor remediation effect; biodegradation remediation degrades organic pollutants into inorganic harmless substances, and has advantages such as low cost, simple remediation process, and no secondary pollution, and is being gradually widely applied to various polluted sites. However, most of the polluted sites in coastal cities in China exhibit low-permeability characteristics. The strong compactness of low-permeability clay seriously hinders the large-scale injection of remediation agents. It can only rely on the self-permeation ability of the microbial flora to migrate to deeper polluted areas. However, the self-migration speed of the flora is limited, resulting in insufficient contact between the remediation agent and the polluted soil, thus leading to problems such as small remediation scope and poor remediation effect.

[0003] There are two problems in the current biodegradation remediation technology: on the one hand, due to the secrecy and complexity of the underground structure in low-permeability polluted sites, it is impossible to effectively regulate and control the biological remediation process of the underground space, it is difficult to master processes such as the injection speed and injection volume of biological agents, it is impossible to monitor the remediation degradation effect in real time and adjust the remediation process according to the monitoring effect, and microorganisms have a strong dependence on the living environment. The variability of the underground environment limits the activity of microorganisms, and it is necessary to adopt environment-driven means to improve the activity of microorganisms, so as to accelerate the decomposition of pollutants by microorganisms; on the other hand, when the traditional resistivity monitoring method is applied to surface monitoring, the electrodes are easy to insert into the soil on the surface, making the monitoring results stable and reliable. However, when the resistivity method monitors the resistivity change in a deeper underground area, electrodes need to be installed in the monitoring well for cross-hole measurement to meet the test depth requirements. However, installing electrodes in a narrow monitoring well has become a major problem. It is difficult to insert and pull out the electrodes, and it is easy to occur that the electrodes are not inserted enough, resulting in poor contact between the electrodes and the soil, thus seriously affecting the monitoring of the remediation effect. Moreover, it is difficult to pull out the electrodes for reuse after use, resulting in an increase in remediation costs and waste of resources. It is urgent to solve the problems of electrode insertion in the remediation monitoring system and the recycling of monitoring devices. Summary of the Invention

[0004] In view of the deficiencies of the prior art, the present invention provides a fracturing-enhanced biodegradation repair system and method for low-permeability polluted formations. By using a cross-resistivity monitoring device to dynamically regulate the injection and repair process of biopharmaceuticals under the action of environmental driving, further, an electrode telescopic device and a reaction force stretching device are used to realize the reuse of important components of the repair system, achieving the purpose of green economy and efficient repair.

[0005] To achieve the above object, the technical solution of the present invention is as follows: Technical solution one: A fracturing-enhanced biodegradation repair system for low-permeability polluted formations, comprising a casing 1, a hydraulic fracturing device, a biopharmaceutical injection device, a cross-resistivity monitoring device, a pH driving device, a thermal resistance driving device, and an on-line monitoring and control system 13, wherein: The casing 1 is arranged in the soil of the polluted site to prevent the soil near the borehole from collapsing, and a plurality of holes are opened on the casing 1 for serving as injection channels for fracturing fluid, biopharmaceuticals, and pH solution; The hydraulic fracturing device is used to create fractures in the soil to provide a channel for the transportation of biopharmaceuticals; The biopharmaceutical injection device is used to transport the biopharmaceuticals through the fractures to the polluted soil; The cross-resistivity monitoring device is used to monitor the resistivity change in real time to adjust the injection amount and injection process of biopharmaceuticals; The pH driving device is used to change the acidity and alkalinity of the soil, and the thermal resistance driving device is used to adjust the soil temperature. By the pH driving device and the thermal resistance driving device, the microbial activity and reproduction speed are increased, and the decomposition of organic pollutants by microorganisms is accelerated; The on-line monitoring and control system 13 is connected to the hydraulic fracturing device, the biopharmaceutical injection device, the cross-resistivity monitoring device, the pH driving device, and the thermal resistance driving device, and on-line monitors and controls the operation of the entire repair system.

[0006] Technical solution two: A fracturing-enhanced biodegradation repair system for low-permeability polluted formations, comprising a casing 1, a hydraulic fracturing device, a biopharmaceutical injection device, a cross-resistivity monitoring device, a pH driving device, a thermal resistance driving device, and an on-line monitoring and control system 13, further comprising a well pipe 2, an electrode telescopic device 4, and a reaction force stretching device 5, wherein: The casing 1 is arranged in the soil of the polluted site to prevent the soil near the borehole from collapsing, and a plurality of holes are opened on the casing 1 for serving as injection channels for fracturing fluid, biopharmaceuticals, and pH solution; The hydraulic fracturing device is used to create fractures in the soil to provide a channel for the transportation of biopharmaceuticals; The biological agent injection device is used to transport the biological agent through the cracks to the contaminated soil; The cross resistivity monitoring device is used to monitor the resistivity change in real time to adjust the injection amount and injection process of the biological agent; The pH driving device is used to change the soil pH value, and the thermal resistance driving device is used to adjust the soil temperature. By the pH driving device and the thermal resistance driving device, the microbial activity and reproduction rate are increased, and the microbial decomposition of organic pollutants is accelerated; The on-line monitoring and control system 13 is connected to the hydraulic fracturing device, the biological agent injection device, the cross resistivity monitoring device, the pH driving device, and the thermal resistance driving device, and on-line monitors and controls the operation of the entire repair system; The well pipe 2, the electrode telescopic device 4, and the reaction force stretching device 5 are used to lower the electrodes of the cross resistivity monitoring device to the appropriate positions in the underground drilling wells to realize the insertion and extraction of the electrodes in the soil.

[0007] Technical solution three: A method for fracturing and strengthening biodegradation repair of low-permeability contaminated formations is realized based on the repair system of the above technical solution one or technical solution two. The implementation process includes the following steps: Step one: Drill a well and construct a well; Step two: Install the main components of the repair system; Step three: Use the hydraulic fracturing device to realize hydraulic fracturing; Ensure that the fracturing fluid injection pipe 802 is connected to the fracturing injection hole 101. Open the hydraulic fracturing injection pump 801 of the hydraulic fracturing device through the on-line monitoring and control system 13, inject high-pressure water at the fracturing injection hole 101 for hydraulic fracturing, form cracks 3 near the fracturing injection hole 101, and transport proppants in the cracks to form a chemical agent injection channel to prevent the cracks from closing; Step four: Use the cross resistivity monitoring device to realize cross-hole resistivity monitoring; Connect all the electrodes 703 in the two underground wells to the electrode wire interfaces 702 of the cross resistivity monitoring device respectively, connect the mobile power supply 704 and the resistivity monitoring system 701. According to the on-line monitoring and control system 13, control any two electrodes in the two underground wells to provide current, and the remaining any two electrodes test the voltage. Calculate the resistivity of the area between the two underground wells according to the resistivity test principle, monitor once every fixed time interval, and continuously monitor on-line; Step five: Use the biological agent injection device to realize the injection of the repair agent; Prepare a mixed solution of microbial inoculum and growth promoter, ensure that the biopharmaceutical injection pipe 602 is connected to the biopharmaceutical injection hole 102, turn on the biopharmaceutical injection pump 601 using the online monitoring and control system 13, and inject the microbial remediation agent into the crack 3 along the biopharmaceutical injection pipe 602. Conduct resistivity monitoring based on the relationship between the microbial injection volume and the resistivity change, and use the online monitoring and control system 13 to regulate the microbial injection volume and injection speed; Step Six: Realize the driving of pH and temperature environment using the pH driving device and the thermal resistance driving device; According to the resistivity monitoring results fed back by the online monitoring and control system 13, obtain the decomposition rate of pollutants and the remediation area. Use the online monitoring and control system 13 to control the temperature sensor 1003 of the thermal resistance driving device and the pH sensor 903 of the pH driving device to respectively test the environmental temperature and acidity at the crack 3. According to the suitable acidity and temperature for the survival of microorganisms, the online monitoring and control system 13 turns on the thermal resistance driving device and the pH driving device, adjusts the soil temperature and pH, enhances the microbial activity, accelerates the decomposition of organic pollutants by microorganisms, and improves the remediation efficiency and expands the remediation scope; Step Seven: Conduct integrated collaborative work of resistivity monitoring, bioremediation, and environmental driving; Step Eight: Recover the remediation system; Step Nine: Reinstall the remediation system in the next borehole to carry out bioremediation.

[0008] Adopting the above solution, the beneficial effects of the present invention are: A fracturing-enhanced biodegradation remediation system for low-permeability contaminated formations of the present invention has the advantages of simple structure, low cost, strong controllability, wide remediation range, and precise remediation.

[0009] Aiming at the problems of low permeability of low-permeability contaminated formations, difficult effective injection and control of remediation agents, high remediation efficiency and cost, etc., the present invention proposes an integrated control system of fracturing enhancement, biodegradation remediation, environmental driving, and real-time remediation monitoring. The resistivity information fed back by the cross resistivity monitoring device is used to guide the biopharmaceutical injection device. The injection volume and injection speed of the agent are precisely controlled through the relationship between the microbial injection volume M and the resistivity change to effectively avoid problems such as insufficient agent injection and excessive agent injection, and greatly save the remediation cost; A dual environmental driving device using a pH driving device and a thermal resistance driving device is used to change the soil environment. The temperature and pH value of the soil in the polluted area are measured by a temperature sensor and a pH sensor. According to the fact that microorganisms show good degradation ability and activity in the temperature range of 20-35 °C and the pH range of 6-8, the environmental conditions of the microorganisms are adjusted by the pH driving device and the thermal resistance driving device to improve the microbial activity, accelerate the decomposition of pollutants by microorganisms in a larger polluted area, and effectively improve the injection effect and repair efficiency.

[0010] Furthermore, the cross-resistivity monitoring device using an electrode telescoping device and a reaction force stretching device can insert the electrode deeper into the polluted soil in a narrow underground drilling (also known as an underground well), make the electrode contact the soil well to form a stable electric field, and the resistivity measurement data is more stable and reliable, which is conducive to the accurate monitoring and fine control of the microbial remediation process. In addition, the electrode telescoping device and the reaction force stretching device can realize the recycling of the cross-resistivity monitoring device. After the remediation is completed, the electrode and the well pipe can be pulled out, and the recovered device can be put into the next underground drilling for continued use in remediation monitoring, saving a large amount of remediation costs and effectively solving the problems of inserting the electrode and recycling the electrode in a narrow underground drilling. Description of the Drawings

[0011] Figure 1 It is a schematic diagram of the structure and scenario of a fracturing enhanced biodegradation remediation system for a low-permeability polluted formation in Example 1.

[0012] Figure 2 It is a schematic diagram of the structure of the cross-resistivity monitoring device in Example 1.

[0013] Figure 3 It is a schematic diagram of the structures of the pH driving device and the thermal resistance driving device in Example 1.

[0014] Figure 4 It is a schematic diagram of the structure of the on-line monitoring and control system in Example 1.

[0015] Figure 5 It is a schematic diagram of the working process of the on-line monitoring and control system in Example 1.

[0016] Figure 6 It is a schematic diagram of the relationship between the pollutant concentration and the resistivity in Example 1.

[0017] Figure 7 It is a schematic diagram of the structure and scenario of a fracturing enhanced biodegradation remediation system for a low-permeability polluted formation in Example 2.

[0018] Figure 8 It is a schematic diagram of the structures of the electrode telescoping device and the reaction force stretching device in Example 2.

[0019] Reference Signs: 1 - Casing; 101 - Fracturing injection hole, 102 - Bioreagent injection hole, 103 - pH injection hole; 2 - Well pipe; 201 - Electrode limit hole; 3 - Fracture; 4 - Electrode telescopic device; 401 - Roller, 402 - Compression plate, 403 - Sliding wheel, 404 - Sliding plate, 405 - Electrode spring; 5 - Reaction force stretching device; 501 - Jack, 502 - Fixed plate, 503 - Support rod, 504 - Telescopic connecting rod, 505 - Connector; 601 - Bioreagent injection pump; 602 - Bioreagent injection pipe; 603 - Intelligent flow control valve; 701 - Resistivity monitoring controller; 702 - Electrode wire interface; 703 - Electrode; 704 - Mobile power source; 705 - Current field; 706 - Electrode wire; 801 - Hydraulic fracturing injection pump; 802 - Fracturing fluid injection pipe; 803 - Fracturing fluid injection valve; 901 - pH injection pump; 902 - pH controller; 903 - pH sensor; 904 - pH injection pipe; 905 - pH injection valve; 1001 - Temperature controller; 1002 - Variable temperature resistor; 1003 - Temperature sensor; 1004 - Resistance regulating valve; 11 - Polluted soil; 12 - Cable; 13 - Online monitoring and control system. Detailed implementation mode

[0020] The technical solution provided by the present application will be further described below in conjunction with specific embodiments and their accompanying drawings. In combination with the following description, the advantages and features of the present application will be clearer.

[0021] Example 1: As Figures 1 to 5 shown, a fracturing enhanced biodegradation repair system for low-permeability polluted formations includes a casing 1, a hydraulic fracturing device, a bioreagent injection device, a cross resistivity monitoring device, a pH driving device, a thermal resistance driving device, and an online monitoring and control system 13. Among them: The casing 1 is arranged in the polluted site soil to prevent the soil near the borehole from collapsing, and several holes are opened on the casing 1 to be used as injection channels for fracturing fluid, bioreagent, pH solution, etc.; The hydraulic fracturing device is used to create a fracture 3 in the soil to provide a channel for bioreagent transportation; The bioreagent injection device is used to transport the bioreagent through the fracture 3 to the polluted soil; The cross-resistivity monitoring device is used to monitor the resistivity change in real time to adjust the injection volume and injection process of biocides; The pH driving device is used to change the acidity and alkalinity of the soil, and the thermal resistance driving device is used to adjust the soil temperature. By the pH driving device and the thermal resistance driving device, the microbial activity and reproduction rate are increased, and the decomposition of organic pollutants by microorganisms is accelerated; The on-line monitoring and control system 13 is connected to the hydraulic fracturing device, the biocide injection device, the cross-resistivity monitoring device, the pH driving device, and the thermal resistance driving device to on-line monitor and control the operation of the entire repair system.

[0022] During application, boreholes are drilled in the polluted site and casings 1 are inserted to prevent borehole collapse. The devices of the hydraulic fracturing device, the biocide injection device, the pH driving device, and the thermal resistance driving device are respectively connected to the casing 1, lowered into the boreholes in the polluted site through the casing 1, and connected to the on-line monitoring and control system 13 to complete the installation of the system equipment. The hydraulic fracturing device is started through the on-line monitoring and control system 13, and high-pressure water and proppants are injected into the polluted soil to form fractures 3. Then, bioremediation agents are injected into the fractures 3 through the biocide injection device, and the cross-resistivity monitoring device is used to monitor the process of microorganism decomposition of pollutants in real time. The on-line monitoring and control system 13 accurately controls the injection volume of biocides according to the resistivity change information fed back by the cross-resistivity monitoring device, and calls the pH driving device and the thermal resistance driving device to adjust the microbial living environment to improve the microbial activity to accelerate the purpose of decomposing pollutants.

[0023] Furthermore, the holes opened in the casing 1 include fracturing spray holes 101, biocide injection holes 102, pH injection spray holes 103, and also include installation holes for installing temperature sensors 1004, pH sensors 903, variable temperature resistors 1002, and electrodes 703. During implementation, the number of each hole can be set as needed.

[0024] Furthermore, the hydraulic fracturing device, such as Figure 1 , Figure 4 shown, includes a hydraulic fracturing injection pump 801, a fracturing fluid injection pipe 802, and a fracturing fluid injection valve 803. The hydraulic fracturing injection pump 801 is connected to the fracturing fluid injection pipe 802, and a fracturing fluid injection valve 803 is provided on the fracturing fluid injection pipe 802. The hydraulic fracturing injection pump 801 is connected to the on-line monitoring and control system 13 through a cable 12, and the hydraulic fracturing process is controlled by the on-line monitoring and control system 13.

[0025] Due to the strong compactness of low-permeability clay seriously hindering the injection of the repair agent, a hydraulic fracturing device is used to create a fracture 3 as the agent delivery channel. During implementation, the fracturing fluid injection pipe 802 is connected to the fracturing nozzle 101 of the casing 1 to form a fracturing fluid injection channel; after opening the fracturing fluid injection valve 803, high-pressure water and proppant are sprayed at the fracturing nozzle 101 through the fracturing injection pump 801 to form a fracture 3, and the fracture 3 serves as the bioreagent injection channel of the bioreagent injection device. The proppant prevents the fracture from being compacted and re-closed under the self-weight of the soil mass. The use of the hydraulic fracturing device solves the problem of agent injection due to the lack of a repair agent delivery channel caused by the low porosity of the low-permeability contaminated site.

[0026] Further, as Figure 1 , Figure 4 shown, the bioreagent injection device includes a bioreagent injection pump 601, a bioreagent injection pipe 602, and an intelligent flow control valve 603. The bioreagent injection pump 601 is connected to the bioreagent injection pipe 602, and an intelligent flow control valve 603 is provided on the bioreagent injection pipe 602. The bioreagent injection pump 601 is connected to the on-line monitoring and control system 13 through a cable 12, and the on-line monitoring and control system 13 controls the agent injection process.

[0027] Preferably, as an embodiment, the bioreagent injection holes 102 can be arranged below the fracturing nozzles 101 and all near the fracture 3 so that the repair agent can migrate along the fracture 3 formed by fracturing to the contaminated area. When using the hydraulic fracturing device for fracturing, the bioreagent injection device is closed; when using the bioreagent injection device for bioreagent injection, the hydraulic fracturing device is closed. During implementation, the bioreagent injection pipe 602 is connected to the bioreagent injection hole 102 of the casing 1 to form a bioreagent injection channel; the bioreagent injection pump 601 is used to transport the bioreagent through the bioreagent injection pipe 602 to the bioreagent injection hole 102 and flow through the fracture 3 to be delivered to the contaminated soil. The microorganisms in the bioreagent decompose the organic matter in the contaminated soil, decomposing the organic pollutants into inorganic harmless substances, thereby achieving the purpose of removing pollutants and repairing the soil.

[0028] Further, the cross-resistivity monitoring device, as Figure 2As shown in the figure, it includes a resistivity monitoring controller 701, an electrode wire interface 702, electrode wires 706, electrodes 703, and a mobile power source 704. Among them: The resistivity monitoring controller 701 is used to test and analyze resistivity data and visualize the resistivity change range. It is provided with an electrode wire interface 702, and several electrodes 703 are connected to the electrode wire interface 702 through electrode wires 706; the electrodes 703 are in contact with the soil; the mobile power source 704 is connected to the resistivity monitoring controller 701 through a cable 12 to supply power to the resistivity monitoring controller 701; the resistivity monitoring controller 701 is connected to an on-line monitoring and control system 13 through a cable 12. The resistivity monitoring controller 701 performs resistivity testing and data analysis, and further uses the on-line monitoring and control system 13 to perform biological agent injection regulation on the biological agent injection device according to the analysis results. Specifically, the number of electrodes 703 can be set according to needs.

[0029] The cross resistivity monitoring device uses power supply electrodes (A and B) to supply power to the ground. At the same time, the potential difference is observed at the measuring electrodes (M1, N1, M2, N2, M3, and N3), and the resistivity is calculated. In the embodiment, as Figure 2 shown in the figure, four electrodes are provided on the outside of the first casing, namely A, M1, M2, and M3; four electrodes are provided on the outside of the second casing, namely B, N1, N2, and N3; the electrode A and the electrode B are used as power supply electrodes to provide current to form a current field 705; the electrodes M1, M2, and M3 on the outside of the first casing and the electrodes N1, N2, and N3 on the outside of the second casing are used as measuring electrodes, and the resistivity is calculated by the voltage values measured by any two measuring electrodes. The resistivity monitoring controller 701 automatically powers on, tests the voltage, and calculates the resistivity data that changes with time at regular intervals. According to the resistivity formula, the resistivity change law caused by the degradation of pollutants in the area between the two casings is calculated. The resistivity calculation formula is: (1) In the formula, ρ is the medium resistivity, I is the current intensity leading to the ground, is the potential difference between the potential electrodes, K is called the geometric device factor, which depends on the relative positions of the electrodes, K The expression of (2) In the formula, A and B represent the power supply electrodes, M and N represent the measuring electrodes, and AM, BM, AN, and BN are the distances from the power supply electrodes to the measuring electrodes.

[0030] The present invention uses time-lapse resistivity method to monitor the pollutant degradation process. The resistivity monitoring principle is based on the fact that there is a certain non-linear relationship between resistivity and pollutant concentration. In a low-permeability clay contaminated site, the decomposition of pollutants by microorganisms leads to a decrease in pollutant concentration, and the corresponding resistivity will also decrease. Therefore, the change in pollutant concentration can be dynamically monitored by the change of resistivity over time. Based on Archie's law, the pollutant concentration in low-permeability clay is obtained and resistivity relationship: (3) In the formula, is the porosity, is the pollutant concentration, is the resistivity of the aqueous phase, is the total resistivity of all components, is the cementation exponent, is the resistivity of soil particles. The parameters of the low-permeability contaminated site are taken as: , , , , the relationship between pollutant concentration and resistivity is as shown in Figure 6 .

[0031] According to formula (3), the relationship between the change in resistivity and the change in pollutant concentration can be obtained as: (4) In the formula, is the proportionality coefficient, indicating the influence of pollutant concentration on the change in resistivity.

[0032] By directly measuring the rate of microbial decomposition of organic pollutants through laboratory experiments, the microbial decomposition rate constant k is obtained. The rate of microbial decomposition of organic pollutants can be expressed as: (5) Assume that the total amount M of microorganisms is proportional to the total amount of decomposed pollutants, then the amount of microorganisms required can be expressed as: (6) In the formula, is the proportionality coefficient, indicating the amount of microorganisms required for decomposing unit pollutants.

[0033] Combining formula (4)~formula (6), the relationship between the amount of injected microorganisms M and the change in resistivity is: (7) The on-line monitoring and control system 13 according to the amount of injected microorganisms M and the change in resistivity Regulate according to the relational expression between, such as Figure 5 shown. Before injecting the biopharmaceutical, use a cross-resistivity monitoring device to perform a resistivity test once to obtain the background initial resistivity , after starting to inject the medicine, perform a resistivity test at fixed intervals, such as every 10 minutes, to obtain the resistivity change value , according to the resistivity change value Judge the decomposition rate of pollutants and the repair area, and then adjust the microbial injection volume M of the biopharmaceutical injection device according to the resistivity feedback information. That is, when the resistivity changes rapidly, it indicates that the microbial degradation rate is fast, and at this time, the injection volume of the microbial medicine should be increased. On the contrary, when the resistivity change is small, the rate of microbial degradation of pollutants is slow, and the injection volume of microorganisms should be reduced. Regulate the microbial injection volume M of the biopharmaceutical injection device through the resistivity feedback information tested by the cross-resistivity monitoring device to achieve precise control of the biopharmaceutical and effectively avoid waste caused by insufficient or excessive injection of the medicine.

[0034] In addition, when the medicine is transported to the area not covered by hydraulic fracturing cracks, it is difficult to effectively inject the medicine. Use a pH drive device and a thermal resistance drive device to adjust the soil environment to improve the microbial activity, drive the microorganisms to move towards nutrients such as pollutants, and accelerate the further decomposition of organic pollutants by microorganisms. This repair system can save a large amount of capital and time costs and effectively improve the repair efficiency.

[0035] Furthermore, the pH drive device, such as Figure 1 , Figure 3 , Figure 4 shown, includes a pH injection pump 901, a pH controller 902, a pH sensor 903, a pH injection pipe 904, and a pH injection valve 905. The pH sensor 903 is arranged near the lower part of the crack 3. The pH controller 902 and the pH sensor 903 are connected by a cable to form a pH test system for obtaining the acidity and alkalinity value of the test area; the pH controller 902 and the pH injection pump 901 are connected by a cable to control the pH adjustment process. The pH injection pump 901, the pH injection pipe 904, and the pH injection valve 905 are connected to form a pH adjustment system; the pH controller 902 and the on-line monitoring and control system 13 are connected by a cable 12. The pH controller 902 performs acidity and alkalinity tests and analyzes, and further regulates the pH controller 902 by the on-line monitoring and control system 13 according to the test results to control the pH test and the pH adjustment process.

[0036] During implementation, connect the pH injection pipe 904 to the pH injection nozzle 103 of the casing 1 to form a pH solution injection channel; use the pH injection pump 901 to transport the pH solution through the pH injection pipe 904 to the pH injection nozzle 103 and deliver it to the contaminated soil. Since the suitable pH range for microorganisms is approximately 6 - 8, an overly acidic or alkaline environment will inhibit the activity of microorganisms. The pH value in the soil is tested by the pH sensor 903 connected to the pH controller 902, and the online monitoring and control system 13 regulates the pH controller 902 according to the tested acidity and alkalinity information. The pH controller 902 injects the pH solution through the pH injection pump 901 to change the acidity and alkalinity of the soil to be close to 6 - 8, enhancing the activity of microorganisms, accelerating the decomposition of organic pollutants by microorganisms, and accelerating the repair efficiency.

[0037] In the embodiment, the pH injection nozzle 103 is located between the fracturing nozzle 101 and the biocatalyst injection hole 102 and is disposed near the crack 3, facilitating the injection of liquid into the crack 3. The pH sensor 903 is disposed below the crack 3, and the number of pH sensors 903 can be set as needed.

[0038] Further, as shown in Figure 1 , Figure 4 , the thermal resistance driving device includes a temperature controller 1001, a variable temperature resistor 1002, a temperature sensor 1003, and a resistance regulating valve 1004. The variable temperature resistor 1002 and the temperature sensor 1003 are disposed near the upper part of the crack 3. The temperature controller 1001 is connected to the temperature sensor 1003 through a cable 12 for obtaining temperature information; the temperature controller 1001 is connected to the variable temperature resistor 1002 through a cable 12, and a resistance regulating valve 1004 is connected to the cable for controlling the variable temperature resistor 1002 to change the temperature according to the temperature information. The temperature controller 1001 is connected to the online monitoring and control system 13 through a cable 12, and the online monitoring and control system 13 controls the temperature testing and temperature adjustment processes.

[0039] Since microorganisms exhibit good degradation ability within the temperature range of 20 - 35°C, the temperature of the soil in the contaminated area is tested by the temperature sensor 1003. The online monitoring and control system 13 regulates the temperature controller 1001 according to the tested temperature information, changes the soil temperature through the variable temperature resistor 1002, and adjusts the soil temperature to 20 - 35°C as much as possible, improving the activity and reproduction speed of microorganisms, accelerating the decomposition of organic pollutants by microorganisms, and thus improving the repair efficiency.

[0040] In the embodiment, the variable temperature resistor 1002 and the temperature sensor 1003 are disposed above the crack 3, and the number of the variable temperature resistor 1002 and the temperature sensor 1003 can be set as needed.

[0041] Embodiment 2: This embodiment is a further improvement on Embodiment 1.

[0042] As Figure 7 shown, a fracturing enhanced biodegradation remediation system for low-permeability contaminated formations adds a well pipe 2, an electrode telescopic device 4 and a reaction force stretching device 5 on the basis of the fracturing enhanced biodegradation remediation system of Embodiment 1, wherein: The diameter of the well pipe 2 is smaller than that of the casing 1, and a plurality of electrode limiting holes 201 are opened in the middle of the side wall of the well pipe 2, and the well pipe 2 is embedded in the casing 1; There are a plurality of electrode telescopic devices 4, which are arranged inside the well pipe 2 and connected to the well pipe 2. The electrode telescopic device 4 is connected to the electrode 703, and the electrode 703 is arranged at the electrode limiting hole 201 of the well pipe 2; The reaction force stretching device 5 is connected to the electrode telescopic device 4 and arranged on the ground at the top of the well pipe 2; The well pipe 2, the electrode telescopic device 4 and the reaction force stretching device 5 are used to lower the electrode 703 to a suitable position in the underground drilling, so as to realize the insertion and extraction of the electrode 703 in the soil.

[0043] The electrode telescopic device 4, the reaction force stretching device 5 and the cross resistivity monitoring device cooperate to insert the electrode 703 into the narrow underground drilling, better realize the contact between the electrode and the soil, obtain stable and reliable resistivity monitoring results, and then can more accurately regulate the repair process according to the monitoring results. In addition, the electrode telescopic device 4 and the reaction force stretching device 5 can realize the recycling of the electrode 703. After the repair is completed, the electrode 703 and the well pipe 2 can be pulled out and put into the next underground drilling to continue to be used for repair monitoring, saving a large amount of repair costs and solving the problem of electrode installation in the narrow monitoring well.

[0044] Further, as Figure 8 shown, the reaction force stretching device 5 includes a jack 501, a fixing plate 502, a support rod 503, a telescopic connecting rod 504 and a connecting piece 505. Among them: the upper and lower fixing plates 502 are fixedly connected into a support frame through the support rod 503. The jack 501 is arranged between the two fixing plates 502. The upper end of the telescopic connecting rod 504 is fixedly connected to the jack 501 through the connecting piece 505, and the up and down movement of the telescopic connecting rod 504 is driven by the extension and compression of the jack 501.

[0045] In the embodiment, the upper end of the telescopic connecting rod 504 is welded to the jack 501 through the connecting piece 505, and the fixing plate 502 and the support rod 503 are connected by welding.

[0046] Further, as Figure 8As shown in the figure, the electrode telescopic device 4 includes a roller 401, a compression plate 402, a sliding wheel 403, a sliding plate 404, and an electrode spring 405. Among them: The roller 401 is connected to the middle of the telescopic connecting rod 504 of the reaction force stretching device 5, facilitating the roller 401 and the telescopic connecting rod 504 to move in the same direction simultaneously; The sliding plate 404 is horizontally arranged below the roller 401 and is connected to the well pipe 2. The sliding plate 404 is provided with a groove channel; The compression plate 402 is an inclined plane structure, and the inclined plane faces the roller 401 and is located below the roller 401. A sliding wheel 403 is provided at the bottom of the compression plate 402. The sliding wheel 403 is in the groove channel of the sliding plate 404, enabling the compression plate 402 to slide along the groove channel on the sliding plate 404 through the sliding wheel 403 at its bottom. The left end of the compression plate 402 is fixedly connected to the electrode 703; The electrode 703 is located in the well pipe 2. The electrode spring 405 is horizontally arranged outside the electrode 703, and both ends of the electrode spring 405 are connected to the well pipe 2 and the compression plate 402 respectively. In the initial state where the electrode 703 is not inserted into the soil, the electrode spring 405 is not compressed and remains in a natural telescopic state. When the electrode 703 is inserted into the soil for resistivity monitoring, the electrode spring 405 remains in a compressed state. Under the compression and rebound action of the electrode spring 405, the up and down movement of the roller 401 drives the compression plate 402 to move left and right on the sliding plate 404, thereby driving the insertion and extraction of the electrode 703.

[0047] In the embodiment, the roller 401 is welded to the middle of the telescopic connecting rod 504 of the reaction force stretching device 5.

[0048] Furthermore, the electrode limiting hole 201 of the well pipe 2 is provided with a groove for fixing the position of the electrode spring 405.

[0049] Drill a group of underground wells in the low-permeability contaminated soil area and lower the casing 1. After connecting the electrode telescopic device 4 and the well pipe 2 as a whole and lowering them into the casing 1, by compressing the jack 501 of the reaction force stretching device 5, under the action of the fixed plate 502 and the support rod 503, the telescopic connecting rod 504 moves downward, thereby driving the roller 401 to roll downward. During the downward rolling process of the roller 401, it will squeeze the compression plate 402 to the left. The compression plate 402 moves leftward on the sliding plate 404 through the sliding wheel 403, thereby compressing the electrode spring 405. The electrode 703 follows the movement of the compression plate 402 and smoothly inserts from the narrow well into the soil, realizing stable contact between the electrode and the soil and being able to more accurately monitor the bioremediation process.

[0050] After the bioremediation monitoring work is completed, the electrode telescopic device 4 and the reaction force stretching device 5 can be used to recycle the electrode 703. By extending the jack 501, since the telescopic connecting rod 504 is welded to the connecting member 505 of the jack 501, the jack 501 will drive the telescopic connecting rod 504 to move upward. When the telescopic connecting rod 504 moves upward, the roller 401 will roll upward together. The compression plate 402 will slide to the right under the action of the springback of the electrode spring 405. Since the electrode 703 is welded to the compression plate 402, when the compression plate 402 slides to the right, the electrode 703 will be pulled out of the soil. The electrode 703 will spring back into the well pipe 2, and finally the well pipe 2 and the electrode telescopic device 4 will be pulled out of the casing 1 together, which is convenient for reinstallation and utilization in the next polluted area, saving a large amount of repair costs and effectively solving the limitation problem that the electrode 703 can only be used once.

[0051] Embodiment 3: A fracturing-enhanced biodegradation repair method for low-permeability polluted formations is realized based on the repair system of the above embodiment. The implementation process includes the following steps: Step 1: Drilling and well construction.

[0052] Use a drilling rig to drill a number of underground wells with a diameter of 200 mm in the polluted site, and the well spacing between adjacent underground wells is 5-10 m.

[0053] Step 2: Installation of the main components of the repair system.

[0054] Pass the fracturing fluid injection pipe 802 of the hydraulic fracturing device through the inner wall of the casing 1 and connect it to the fracturing injection hole 101 by bolts to form a fracturing fluid injection channel, and connect the hydraulic fracturing injection pump 801 to the online monitoring and control system 13 through the cable 12; Pass the bioreagent injection pipe 602 of the bioreagent injection device through the inner wall of the casing 1 and connect it to the bioreagent injection hole 102 by bolts to form a reagent injection channel, and connect the bioreagent injection pump 601 to the online monitoring and control system 13 through the cable 12; Pass the pH injection pipe 904 of the pH driving device through the inner wall of the casing 1 and connect it to the pH injection hole 103 by bolts to form a pH solution injection channel, and connect the pH controller 902 to the pH injection pump 901 and the online monitoring and control system 13 respectively through the cable 12; weld the pH sensor 903 on the casing 1 and connect it to the pH controller 902 through the cable 12; Weld the temperature sensor 1003 and the variable temperature resistor 1002 of the thermal resistance driving device on the casing 1 and connect them to the temperature controller 1001 through the cable 12 respectively, and connect the temperature controller 1001 to the online monitoring and control system 13 through the cable 12; Connect the resistivity monitoring controller 701 of the cross resistivity monitoring device to the online monitoring and control system 13 through the cable 12. Connect a number of electrodes 703 to the electrode wire interface 702 through the electrode wires 706. Connect the mobile power supply 704 to the resistivity monitoring controller 701 through the cable 12, and insert the electrodes 703 into the soil. Place the casing 1 in the underground well to prevent cave - in. After the well construction is completed, let the soil mass stabilize for a period of time. So far, the system has completed the equipment installation.

[0055] Further, for the repair system in Embodiment 2, the electrode 703 passes through the electrode limiting hole 201 of the well pipe 2 and inserts into the soil through the electrode hole position on the casing 1. Specifically: Connect the electrode telescopic device to the well pipe 2, including: weld the sliding plate 404 to the well pipe 2. Install the sliding wheel 403 at the bottom of the compression plate 402. Weld the compression plate 402 to the electrode 703 and place the sliding wheel 403 in the groove channel of the sliding plate 404. Place the electrode spring 405 in the groove of the electrode limiting hole 201. The electrode 703 passes through the electrode spring 405 and aligns with the electrode limiting hole 201. Weld the roller 401 to the middle of the telescopic connecting rod 504 of the reaction force stretching device 5. Insert the well pipe 2 together with the electrode telescopic device 4 into the casing 1, and align the electrode limiting hole 201 of the well pipe 2 with the electrode hole position opened on the casing 1. Set the reaction force stretching device 5 on the ground at the top of the well pipe 2, and put the telescopic connecting rod 504 of the reaction force stretching device 5 into the well pipe 2. Turn on the jack 501 of the reaction force stretching device 5 for compression. The telescopic connecting rod 504 moves downward and drives the compression plate 402 to move leftward, inserting the electrode 703 into the soil to make the contact between the electrode and the soil more stable.

[0056] Step three: Implement hydraulic fracturing using the hydraulic fracturing device.

[0057] Ensure that the fracturing fluid injection pipe 802 is connected to the fracturing nozzle 101. Open the hydraulic fracturing injection pump 801 of the hydraulic fracturing device through the online monitoring and control system 13. Inject high - pressure water at the fracturing nozzle 101 for hydraulic fracturing, form a crack 3 near the fracturing nozzle 101, and transport high - permeability fine sand proppant in the crack to form a chemical injection channel. The proppant injection pressure is about 600 kPa to prevent the crack from closing.

[0058] Step four: Implement cross - hole resistivity monitoring using the cross resistivity monitoring device.

[0059] Connect all the electrodes 703 in the two underground wells to the electrode wire interface 702 of the cross resistivity monitoring device respectively, connect the mobile power supply 704 to the resistivity monitoring system 701, and according to the on-line monitoring and control system 13, control any two electrodes in the two underground wells to provide current, and the remaining any two electrodes to measure voltage. Calculate the resistivity of the area between the two underground wells according to the resistivity measurement principle, monitor it every 10 minutes, and continuously monitor on-line.

[0060] Step Five: Use the bioreagent injection device to achieve the injection of the repair reagent.

[0061] Prepare a mixed solution of microbial inoculum and growth promoter, ensure that the bioreagent injection pipe 602 is connected to the bioreagent injection hole 102, use the on-line monitoring and control system 13 to turn on the bioreagent injection pump 601, and inject the microbial repair reagent along the bioreagent injection pipe 602 into the crack 3. Conduct resistivity monitoring based on the relationship between the amount of microbial injection and the change in resistivity, and use the on-line monitoring and control system 13 to regulate the amount of microbial injection and the injection speed. The injection pressure shall not be greater than 5 MPa to avoid affecting the growth of microorganisms.

[0062] Step Six: Use the pH driving device and the thermal resistance driving device to achieve the driving of the pH and temperature environment.

[0063] According to the resistivity monitoring results feedback by the on-line monitoring and control system 13, obtain the decomposition rate of pollutants and the repair area. Use the on-line monitoring and control system 13 to control the temperature sensor 1003 of the thermal resistance driving device and the pH sensor 903 of the pH driving device to measure the ambient temperature and acidity at the crack 3 respectively. According to the suitable acidity and temperature for the survival of microorganisms, the on-line monitoring and control system 13 turns on the thermal resistance driving device and the pH driving device, and adjusts the soil temperature and pH to 20 - 35 °C and 6 - 8 respectively as much as possible to enhance the microbial activity, accelerate the decomposition of organic pollutants by microorganisms, and improve the repair efficiency and expand the repair scope.

[0064] Step Seven: The resistivity monitoring, bioremediation, and environmental driving work in an integrated and collaborative manner.

[0065] Continue the resistivity monitoring in the operation mode of Step Four, accurately control the amount of reagent injection according to the pollution repair situation feedback by the resistivity monitoring results, and use the pH driving device and the thermal resistance driving device to achieve the driving of the pH and temperature environment, enhance the microbial activity, improve the migration speed of the repair reagent and expand the repair scope, effectively avoiding problems such as insufficient and excessive reagent injection, and greatly improving the repair efficiency.

[0066] Step Eight: Recover the repair system, including important components such as electrodes 703, variable temperature resistors 1002, temperature sensors 1003, pH sensors 903, and sleeves 1.

[0067] Furthermore, for the repair system in Embodiment 2, the electrode 703 is recycled through the electrode telescopic device 4 and the reaction force stretching device 5. Specifically, the jack 501 of the reaction force stretching device 5 is activated for stretching. As the jack 501 extends, the telescopic connecting rod 504 moves upward. When the telescopic connecting rod 504 moves upward, the roller 401 rolls upward along with it. The compression plate 402 will slide to the right under the elastic rebound of the electrode spring 405, pulling out the electrode 703 from the soil and causing the electrode 703 to rebound into the well pipe 2. Then, the well pipe 2 and the electrode telescopic device 4 are pulled out of the casing 1 together. Finally, the casing 1 and the variable temperature resistor 1002, temperature sensor 1003, and pH sensor 903 connected to it are pulled out of the underground well together, facilitating reinstallation and reuse in the next contaminated area. By reusing, the repair cost is significantly reduced.

[0068] Step Nine: Reinstall the repair system in the next borehole to carry out bioremediation.

[0069] Reinstall the components of the recycled repair system in other underground wells in the contaminated site, and repeat Steps Two to Eight. Use the repair system to carry out bioremediation of pollutants in different underground wells in sequence until all contaminated areas in the site are treated.

[0070] The above description is only a description of the preferred embodiments of the present application and does not limit the scope of the present application in any way. Any change or modification made by any person skilled in the art based on the disclosed technical content should be regarded as an equivalent effective embodiment and falls within the scope of protection of the technical solution of the present application.

Claims

1. A low-permeability contaminated stratum fracturing enhanced biodegradation repair system, characterized in that: It comprises a casing (1), a hydraulic fracturing device, a biopharmaceutical injection device, a cross resistivity monitoring device, a pH driving device, a thermal resistance driving device and an online monitoring and control system (13), wherein: The casing (1) is arranged in the soil of the contaminated site to prevent the soil near the borehole from collapsing, and a plurality of holes are provided on the casing to serve as injection channels for fracturing fluid, biological agent, and pH liquid; The hydraulic fracturing device is used to create cracks in the soil to provide channels for the delivery of biological agents; The biological agent injection device is used to transport the biological agent through the cracks to the contaminated soil; The cross-resistivity monitoring device is used to monitor resistivity changes in real time to adjust the injection amount and injection process of the biological agent; The pH driving device is used to change the pH of the soil, and the thermal resistor driving device is used to adjust the soil temperature. The pH driving device and the thermal resistor driving device are used to increase the activity and reproduction speed of microorganisms, thereby accelerating the decomposition of organic pollutants by microorganisms. The online monitoring and control system (13) is connected to the hydraulic fracturing device, the biological agent injection device, the cross resistivity monitoring device, the pH driving device, and the thermal resistance driving device to monitor and control the operation of the entire repair system online.

2. A low-permeability contaminated stratum fracturing enhanced biodegradation repair system as claimed in claim 1, characterized in that: The holes formed in the casing (1) include a fracturing spray hole (101), a biological agent injection hole (102), a pH injection spray hole (103), and also include installation holes for installing a temperature sensor (1004), a pH sensor (903), a variable temperature resistor (1002), and an electrode (703).

3. A low-permeability contaminated stratum fracturing enhanced biodegradation repair system as claimed in claim 1, characterized in that: The hydraulic fracturing device comprises a hydraulic fracturing injection pump (801), a fracturing fluid injection pipe (802) and a fracturing fluid injection valve (803), wherein: The hydraulic fracturing injection pump (801) is connected to a fracturing fluid injection pipe (802), a fracturing fluid injection valve (803) is provided on the fracturing fluid injection pipe (802), and the hydraulic fracturing injection pump (801) is connected to an online monitoring and control system (13) via a cable (12), and the hydraulic fracturing process is controlled by the online monitoring and control system (13).

4. A low-permeability contaminated stratum fracturing enhanced biodegradation repair system as claimed in claim 1, characterized in that: The biopharmaceutical injection device comprises a biopharmaceutical injection pump (601), a biopharmaceutical injection tube (602) and an intelligent flow control valve (603), wherein: The biopharmaceutical injection pump (601) is connected to the biopharmaceutical injection pipe (602), an intelligent flow control valve (603) is provided on the biopharmaceutical injection pipe (602), and the biopharmaceutical injection pump (601) is connected to the online monitoring and control system (13) via a cable (12), and the biopharmaceutical injection process is controlled by the online monitoring and control system (13).

5. The low-permeability contaminated stratum fracturing enhanced biodegradation repair system according to claim 1, characterized in that: The cross resistivity monitoring device comprises a resistivity monitoring controller (701), an electrode line interface (702), an electrode line (706), an electrode (703), and a mobile power supply (704), wherein: A resistivity monitoring controller (701) is used for testing and analyzing resistivity data and visualizing the resistivity variation range, and is provided with an electrode line interface (702), to which a plurality of electrodes (703) are connected via electrode lines (706); the electrodes (703) are in contact with soil; a mobile power source (704) is connected to the resistivity monitoring controller (701) via a cable (12) to supply power to the resistivity monitoring controller (701); the resistivity monitoring controller (701) is connected to an online monitoring and control system (13) via a cable (12), and the resistivity monitoring controller (701) performs resistivity testing and data analysis, and further uses the online monitoring and control system (13) to control the injection of a biological agent into a biological agent injection device based on the analysis results.

6. A low-permeability contaminated stratum fracturing enhanced biodegradation repair system as claimed in claim 1, characterized in that: The cross resistivity monitoring device uses a power supply electrode to supply power to the underground, while observing the potential difference at the measuring electrode and calculating the resistivity; The change of pollutant concentration is dynamically monitored by the change of resistivity over time, and the pollutant concentration in low-permeability clay is obtained based on Archie's law and resistivity The relationship is: （3） In the formula, is the porosity, is the pollutant concentration, is the water phase resistivity, is the total resistivity of all components, is the cementation index, is the resistivity of soil particles; According to formula (3), the relationship between resistivity change and pollutant concentration change is: （4） In the formula, is the proportionality coefficient, which represents the effect of pollutant concentration on resistivity change; Directly measure the rate at which microorganisms decompose organic pollutants through laboratory experiments to obtain the microbial decomposition rate constant k , the rate at which microorganisms decompose organic pollutants is expressed as: （5） Assuming that the total amount of microorganisms M is proportional to the total amount of pollutants decomposed, the required amount of microorganisms is expressed as: （6） In the formula, is a proportionality constant, which indicates the amount of microorganisms required to decompose a unit of pollutant; Combining equations (4) to (6), we can get the relationship between microbial injection volume M and resistivity change: The relationship between them is: （7） The online monitoring and control system 13 is based on the above-mentioned microbial injection amount M and resistivity change The relationship between them is regulated.

7. The low-permeability contaminated stratum fracturing enhanced biodegradation repair system according to claim 1, characterized in that: The pH driving device comprises a pH injection pump (901), a pH controller (902), a pH sensor (903), a pH injection tube (904), and a pH injection valve (905), wherein: The pH sensor (903) is arranged near the bottom of the crack (3); the pH controller (902) and the pH sensor (903) are connected via a cable to form a pH test system for obtaining the pH value of the test area; the pH controller (902) and the pH injection pump (901) are connected via a cable to control the pH adjustment process; the pH injection pump (901) is connected to the pH injection pipe (904) and the pH injection valve (905) to form a pH adjustment system; the pH controller (902) and the online monitoring and control system (13) are connected via a cable (12); the pH controller (902) performs pH test and analysis; and the online monitoring and control system (13) further controls the pH controller (902) according to the test result to control the pH test and pH adjustment process.

8. The low-permeability contaminated stratum fracturing enhanced biodegradation repair system according to claim 1, characterized in that: The thermal resistor driving device comprises a temperature controller (1001), a temperature-variable resistor (1002), a temperature sensor (1003) and a resistance regulating valve (1004), wherein: The variable temperature resistor (1002) and the temperature sensor (1003) are arranged near the top of the crack (3); the temperature controller (1001) is connected to the temperature sensor (1003) via a cable (12) for obtaining temperature information; the temperature controller (1001) is connected to the variable temperature resistor (1002) via a cable (12); a resistance regulating valve (1004) is connected to the cable for controlling the variable temperature resistor (1002) to change the temperature according to the temperature information; the temperature controller (1001) is connected to the online monitoring and control system (13) via a cable (12); the online monitoring and control system (13) controls the temperature test and temperature regulation process.

9. A method for reinforcing biodegradation and repairing low-permeability contaminated strata by fracturing based on a system for reinforcing biodegradation and repairing low-permeability contaminated strata according to any one of claims 1 to 8, characterized in that: The implementation process includes the following steps: Step 1: Drilling and well construction; Step 2: Install and repair system components; Step 3: Using a hydraulic fracturing device to achieve hydraulic fracturing; Ensure that the fracturing fluid injection pipe (802) is connected to the fracturing spray hole (101), turn on the hydraulic fracturing injection pump (801) of the hydraulic fracturing device through the online monitoring and control system (13), spray high-pressure water at the fracturing spray hole (101) to perform hydraulic fracturing, form a crack (3) near the fracturing spray hole (101), and transport proppant in the crack to form a drug injection channel to prevent the crack from closing; Step 4: Use the cross resistivity monitoring device to realize cross-hole resistivity monitoring; All electrodes (703) in the two underground wells are respectively connected to the electrode line interface (702) of the cross resistivity monitoring device, and the mobile power supply (704) is connected to the resistivity monitoring system (701). According to the online monitoring and control system (13), any two electrodes in the two underground wells are controlled to provide current, and the remaining any two electrodes are tested for voltage. According to the resistivity test principle, the resistivity of the area between the two underground wells is calculated and monitored once at fixed intervals, and online monitoring is continuously performed; Step 5: injecting the repair agent using a biological agent injection device; A mixed liquid of a microbial agent and a growth promoter is prepared, and the bioagent injection pipe (602) is ensured to be connected to the bioagent injection hole (102). The bioagent injection pump (601) is turned on using the online monitoring and control system (13), and the microbial remediation agent is injected into the crack (3) along the bioagent injection pipe (602). Resistivity monitoring is performed based on a relationship between the amount of microbial injection and the change in resistivity, and the amount of microbial injection and the injection speed are controlled using the online monitoring and control system (13); Step 6: Use pH driving device and thermal resistance driving device to realize pH and temperature environment driving; According to the resistivity monitoring results fed back by the online monitoring and control system (13), the decomposition speed of pollutants and the repair area are obtained, and the temperature sensor (1003) of the thermal resistor drive device and the pH sensor (903) of the pH drive device are controlled by the online monitoring and control system (13) to test the ambient temperature and pH at the crack (3) respectively. According to the pH and temperature suitable for the survival of microorganisms, the online monitoring and control system (13) turns on the thermal resistor drive device and the pH drive device to adjust the soil temperature and pH, thereby increasing the activity of microorganisms, accelerating the decomposition of organic pollutants by microorganisms, and improving the repair efficiency and expanding the repair range; Step 7: Integrated and coordinated work of resistivity monitoring, bioremediation, and environmental drive; Step 8: Recycling and repairing the system; Step 9: Reinstall the repair system in the next borehole and carry out bioremediation.

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