937 results about "Injection well" patented technology

A method of constructing an injection well for a geothermal energy system comprising determining a fracture area of an injection well with a curved wellbore by inputting the curved wellbore path, a set of formation properties, and a fracturing operation, into a fracturing model. The curved wellbore path can promote fracture interference between fracture stresses extending from the injection wellbore. A production model can determine an economic value of the production fluids produced from at least one production well by determining a contact time for the injection fluids to traverse the formation. A design process can iterate the curved wellbore path of the injection well to produce a production fluid with an economic value above a threshold value.

The invention provides an intelligent pressure management system, method and terminal for geological sequestration of carbon dioxide, and the system comprises the steps: collecting the pressure data of the interior and peripheral key positions of each geological reservoir in real time through a pressure monitoring subsystem, and then carrying out the data preprocessing and feature extraction through a data processing and analysis subsystem; and predicting the reservoir pressure change trend in a specific time period in the future. If the predicted reservoir pressure change trend pressure is too high, high-risk related information is transmitted to the intelligent regulation and control subsystem, and the intelligent regulation and control subsystem regulates and controls the reservoir pressure by regulating the flow of a carbon dioxide injection well and a production well or starting a pressure release device according to a preset strategy and dynamically regulates a regulation and control mode according to pressure data. Meanwhile, the communication and monitoring subsystem transmits system operation data to a remote monitoring terminal in real time, so that real-time monitoring is facilitated. Real-time, accurate and automatic regulation and control of the pressure of the geological reservoir are achieved, the stability and safety of the geological reservoir in the carbon dioxide injection process are guaranteed, the geological storage effect of the carbon dioxide is improved, and various negative effects caused by too high pressure are avoided.

The invention relates to the technical field of underground casing monitoring, and discloses an injection well immovable string casing damage rapid detection device based on efficient testing and adjusting, the injection well immovable string casing damage rapid detection device comprises a testing vehicle, a top sheave and a casing, one side in the testing vehicle is provided with a ground control system, and the other side in the testing vehicle is provided with a double-roller winch; a cable is wound on the outer side of the double-roller winch, an electromagnetic flaw detection testing instrument is installed at one end of the cable, an oil pipe is arranged in the casing pipe in a sleeved mode, a plurality of packers are sequentially installed between the outer side of the oil pipe and the inner wall of the casing pipe from top to bottom, and a plurality of water distributors are sequentially distributed in the oil pipe from top to bottom. A water injection well efficient testing and adjusting technology and an electromagnetic flaw detection technology are combined, an electromagnetic flaw detection testing instrument is tripped in through a testing vehicle, cable power supply and communication are tested, a ground control system carries out signal acquisition and processing on the electromagnetic flaw detection instrument, and rapid detection of casing damage of a water injection well immovable string is achieved.

The invention discloses an injection-production well connectivity modeling and yield prediction method and device, and relates to the technical field of oil reservoir engineering. Comprising the following steps: on the basis of preprocessed time sequence injection-production data, constructing a spatial topological graph structure according to screening conditions; constructing a yield prediction model based on the LSTM-GAT network, taking the spatial topological graph structure as the input of a graph attention mechanism, extracting the time dependence characteristics of the gas injection well and the production well by using the long short-term memory network, and extracting the spatial dependence relationship of the gas injection well and the production well by using the graph attention mechanism so as to output the predicted yield of the production well at the future moment; constructing a fitness function, and introducing a whale optimization algorithm to perform global optimization on the injection-production parameters to obtain an optimal injection-production parameter combination; and outputting the optimal injection-production parameter combination. The problems that when an existing method is used for determining the inter-well communication relation, a large amount of geological data and experiment cost are needed, the analysis process is complex, consumed time is long, and accurate optimization of injection-production parameters is difficult to achieve are solved.

A water injection regulation system for water injection well has a float limiting device (A) provided at a wellhead configured to release and capture a float; a ground water delivery device (B) having an outlet in communication with the float limiting device (A), and is configured to inject water into well through the float limiting device (A); and a plurality of downhole water distribution devices, each arranged in a target layer and outside a sidewall of a water-injection string, and configured to monitor production data of the target layer. The float is configured to receive a water distribution instruction to regulate water distribution of each downhole water distribution device, enter the water-injection string (11) with water flow, and float upwards to the wellhead after completing data collection. Each downhole water distribution device is configured to exchange the production data with the water distribution instruction carried by the float.

The invention relates to a deep coal underground gasification method which comprises the following steps: drilling a plurality of gasification wells in a land parcel, sequentially arranging the plurality of gasification wells into three rows from the edge of the land parcel, and fracturing a bottommost coal seam; the first row of gasification wells are injection wells, the second row of gasification wells are production wells, and the bottommost coal seam between the first row of gasification wells and the second row of gasification wells is gasified; when the gasification high-temperature area of the gasified coal seam is expanded to the front edge of the gas cooling area, the second gas gasification well is closed, the third gas gasification well serves as a production well, and the coal seam continues to be gasified; meanwhile, a fourth row of gasification wells are drilled; after the coal bed is gasified, the bottommost coal bed between the second row of gasification wells and the third row of gasification wells is gasified, and so on, the bottommost coal bed between all the rows of gasification wells is gasified; meanwhile, cement paste is injected into the first exhaust gasification well to fill the gasified goaf; and so on, filling the goaf between each row of gasification wells; sequentially gasifying and refilling each coal seam from bottom to top according to the method.

Disclosed herein are systems and methods of gas sequestration of carbon dioxide from a fossil-fueled hydrogen production plant. The method includes producing at least hydrogen and carbon dioxide above ground from a fossil-fueled hydrogen production plant, injecting at least a portion of the hydrogen and carbon dioxide produced from the fossil-fueled hydrogen production plant into a geological hydrogen storage unit and a geological carbon dioxide storage unit, respectively, wherein the portion of the carbon dioxide is injected concurrently with the portion of the hydrogen. The injection of the portion of carbon dioxide and hydrogen underground are performed through carbon dioxide injection well(s) and hydrogen injection well(s), respectively, wherein a hydrogen injection wellhead(s) and a carbon dioxide injection wellhead(s) are located on a multi-well pad proximate the fossil-fueled hydrogen production plant.

The invention discloses an integrated intelligent management and control method and system for underground water pumping and injection based on the Internet of Things, and the method comprises the steps: carrying out the geological investigation of a target region, constructing a three-dimensional geological model, and planning the layout of a pumping and injection well group and a sensor network according to the three-dimensional geological model; deploying a monitoring network and collecting data based on the layout scheme, and fusing a three-dimensional geologic model to construct a polluted site digital twinborn body; groundwater situation data are extracted through the digital twinborn body, a pollutant migration path and a water level dynamic state are predicted by using an LSTM model, and pollution scene simulation information corrected by geologic features is output; by taking the simulation information as input and coupling geological parameters as constraints, generating a pumping and injection well group cooperative control strategy set by adopting a BLMFO double-layer multi-objective optimization algorithm; and finally, a control instruction is executed, the real-time situation is monitored in the repairing process, strategy change suggestions including the flow adjustment amplitude, the agent optimization scheme and equipment operation parameter correction are judged and pushed, the repairing efficiency is improved, and the method adapts to the complex geological environment.

The invention relates to the technical field of oil-gas field development and geothermal energy utilization. The invention provides an underground high-temperature composite fluid heating system, which comprises a crude oil separation device, a catalysis module, a high-temperature fluid generation module, an injection well pattern module, a target reservoir and a production well, and is characterized in that the crude oil separation device is communicated with the catalysis module through a first gas inlet pipeline and a second gas inlet pipeline; a first gas outlet pipeline and a second gas outlet pipeline are communicated with a high-temperature fluid generation module, the high-temperature fluid generation module is communicated with an injection well pattern module through a third gas outlet pipeline, the injection well pattern module is communicated with a target reservoir, and the target reservoir supplies energy to the outside through a fourth gas outlet pipeline. And the production well conveys the energy-supplied gas to the heat energy recovery device through the first recovery pipeline. In this way, efficient and uniform heating of the underground reservoir is achieved, energy consumption is reduced while the energy recovery efficiency is improved, and the problems of low heat conduction efficiency and high energy consumption in deep oil gas and hot dry rock development are solved.

The invention provides a layout method and system for a carbon dioxide injection well and a pressure control well. The method comprises the steps that the reservoir thickness, porosity, permeability and formation pressure distribution data of a target reservoir are obtained; determining a deployment area according to the reservoir thickness, the porosity, the permeability and the formation pressure distribution data; based on a preset carbon dioxide injection well distance, carbon dioxide injection wells are arranged in the deployment area in an equilateral triangle grid mode; and a pressure control well is laid based on the center of the equilateral triangle grid, and the layout of the carbon dioxide injection well and the pressure control well is obtained. According to the technical scheme, the carbon dioxide injection well and the pressure control well are reasonably arranged, and the safety and economical efficiency of carbon dioxide geological sequestration are improved.

The invention belongs to the technical field of carbon dioxide capture and utilization and geological sequestration, and discloses a numerical simulation method for migration of CO2 in stratum.The method comprises the steps that an actual stratum complex geological model is constructed, and then a numerical simulation model is obtained; finely adjusting the numerical simulation model to limit fluid channeling and external substance and energy exchange, and ensuring rapid convergence of operation; the injection of CO2 in different layers is simulated, and the influence of the injection layers on the migration law is analyzed; cO2 injection at different injection speeds and temperatures is simulated to analyze the influence of the injection speeds and temperatures on the migration law; cO2 is simulated to be injected at different injection temperatures under the condition of consistent initial salt concentration, and the influence of dissolved salt on migration and dissolution rules is analyzed; the injection of CO2 at different positions of the reservoir is simulated, and the influence of the injection well position on CO2 storage is analyzed; and optimizing well position arrangement to obtain an optimal well pattern scheme. According to the method, the results of various influence factors are comprehensively analyzed, and then the migration rule of CO2 in the stratum is accurately obtained.

The invention provides a method for predicting and controlling water injection pressure rise of a water injection well, which comprises the following steps of: 1, collecting data of the water injection well according to different characteristics of each stage of water injection development of an oil reservoir; 2, according to the water injection well data, water injection well dynamic analysis is conducted; 3, establishing a water injection well water injection pressure rise prediction model according to oil reservoir factors by taking the water injection pressure as response and the factors influencing the water injection pressure rise as variables; and 4, according to the water injection well water injection pressure rise prediction model, a water injection well pressure rise control method is formulated. According to the water injection well water injection pressure rise prediction and control method, the prediction model is established, the water injection well pressure rise trend is predicted according to the model, a targeted control method is formulated, advanced early warning is achieved, effective water injection is guaranteed, and the purposes of more water injection and good water injection are achieved.

The invention discloses an oil reservoir water content prediction method based on a graph neural network and Transform, and belongs to the technical field of oil and gas field development, and the method comprises the following steps: S1, converting an oil reservoir injection-production model at each time point into a graph structure, and constructing a connection network from a water injection well to a production well; and S2, constructing a GNT proxy model in combination with the graph neural network and Transform, training the GNT proxy model, and predicting the water content of each production well. According to the constructed GNT proxy model, an oil reservoir injection-production structure is converted into graph data through a GCN module, the information transmission strength between nodes is dynamically adjusted through an edge feature enhanced message transmission mechanism, and inter-well communication features are accurately captured; and the multi-head self-attention mechanism of the Transform encoder module is combined to process the time sequence dependence, so that the long-distance time dynamic relationship is effectively modeled, and an efficient and reliable agent model is provided for the dynamic analysis of the oil reservoir.

The invention provides a safety risk control method for geological storage of carbon dioxide and electronic equipment. A distributed optical fiber sensing system is arranged in at least one injection well of the target sealing and storage area in the axial direction of a shaft and penetrates through a main cover layer and a reservoir; the method comprises the following steps: acquiring background data through a distributed optical fiber sensing system, and establishing a multi-parameter baseline model including a temperature field, a strain field and background noise; temperature, strain and sound wave vibration signals are collected in real time, and key features are extracted; the key features extracted in real time are compared with a preset risk feature library, the types of risk events are identified, and the identified risk events are graded according to the spatial range and intensity of the abnormal signals; and according to the type and the grade of the risk event, generating and executing a corresponding control instruction. According to the embodiment of the invention, the optical fibers are distributed in the whole area along the shaft and the target stratum, a three-dimensional monitoring network covering the sealing body is constructed, and the hysteresis quality of traditional point type measurement and periodic exploration is overcome.

The invention provides a layered water injection well injection profile testing system, electronic equipment and a storage medium, and the system comprises a plurality of visible light communication modules which are respectively installed on eccentric water distributors of all water injection layers and on water injection pipe couplings between any two water injection layers; the plurality of sensing monitoring modules are mounted on the eccentric water distributor and are used for acquiring underground monitoring data of the layered water injection well; and the upper computer terminal is used for processing the underground monitoring data based on the group strategy optimization model to obtain an optimized water injection strategy, further generating a water injection control instruction, and transmitting the water injection control instruction to the eccentric water distributors of the water injection layers through a downlink channel. According to the scheme, the LED is used for transmitting data under the dark well, the problems existing in an existing transmission mode are solved, the original water injection well layout structure is not changed through installation of the hardware module, space is saved, and more stable and reliable light transmission can be achieved.

The utility model discloses a well structure for injecting a suspended state repairing agent. The well structure comprises an injection well, a lower end injection pipeline and an upper end injection pipeline, wherein the lower end injection pipeline downwards penetrates into the injection well from the top of the injection well; the upper end injection pipeline is arranged on the side wall of one side of the top of the injection well; and a Y-shaped tee joint is arranged at the bottom of the lower end injection pipeline. By adopting the well structure, the migration and distribution uniformity of the suspended state repairing agent is remarkably improved, the reaction efficiency with pollutants is enhanced, meanwhile, the repairing cost is reduced, the construction period is shortened, and the repairing quality is ensured. Meanwhile, the problem that in a traditional injection method, when the repair depth exceeds the injection range or the repair medium is bed rock, it is difficult to inject suspended-state repair agents is solved.

The invention discloses a CCUS experimental device and method for carbon dioxide flooding and storage, and relates to the technical field of petroleum engineering. The device comprises a three-dimensional oil reservoir physical model, a fluid injection system, a fluid collecting and metering system, a resistivity monitoring system and a fluid migration observation system. The three-dimensional oil reservoir physical model is used for constructing a simulated stratum, and a development well pattern system is installed on the simulated stratum; the fluid injection system is connected with the injection well; the fluid collecting and metering system is connected with the production well; the resistivity monitoring system is provided with a plurality of monitoring points on the simulated stratum; the fluid migration observation system is used for observing a migration path of supercritical carbon dioxide in the three-dimensional oil reservoir physical model; and the distributed optical fiber monitoring system is arranged in the simulated stratum. According to the device and the method, oil reservoir water injection exploitation and CO2 injection oil displacement and CO2 storage stability simulation experiments in the later development period can be realized.

The invention relates to a weak-base three-component combination flooding comprehensive adjustment method after polymer flooding of a first-class oil layer. The problem that a proper comprehensive adjustment method is seriously lacked due to low-efficiency and ineffective circulation of dominant seepage channel development after polymer flooding of a first-class oil layer is solved. The method comprises the steps that S1, in the non-effective period of a producing well, an injection well adopts a double-height injection system, and a dominant seepage channel, injection-production balance and pressure balance are regulated and controlled; s2, in the water content decline period, large-scale separate injection is carried out, injection well measure adjustment is optimized, profile production is improved, and oil production well effectiveness is promoted; s3, in the water content low value period, the injection and production well fracturing mode is optimized; the injection-production capacity is kept; large-scale separate injection is increased, and the interval strength is optimized; and S4, in the water content rising period, high-concentration low-speed injection of the injection well is kept, and water content rising is controlled. According to the method, optimization measures of different injection stages of weak-base three-component combination flooding after polymer flooding of the first-class oil layer are adjusted, dominant seepage channels are blocked, remaining oil of medium and low permeable layers is excavated, and the block development effect is improved.

The invention discloses a carbon dioxide geological sequestration leakage monitoring and early warning system. The system comprises a sensor arrangement module, a data acquisition and processing module, a prediction and early warning module and a linkage control module. The sensor laying module is used for laying pressure sensors, temperature sensors and microseism monitoring equipment on an injection well, a monitoring well and the ground surface, and real-time collection of pressure and temperature of a reservoir and a shaft is achieved by combining distributed optical fiber temperature measurement. And the data acquisition and processing module performs dynamic fitting and trend analysis on the multi-source monitoring data, and calculates to obtain a pressure evolution function. The prediction and early warning module predicts a future pressure state through a threshold value judgment and prediction model and automatically sends out an early warning signal when the future pressure state is close to a critical value, the linkage control module is combined with the injection control unit, the injection rate can be automatically adjusted or adjusted in an auxiliary mode according to an early warning result, risks are reduced, and safety is improved. The system can significantly improve the safety and reliability of carbon dioxide geological sequestration.

The invention discloses a carbon sequestration CO2 multi-layer injection and production collaborative balance system and method.The carbon sequestration CO2 multi-layer injection and production collaborative balance system comprises a multi-layer injection mechanism, a collaborative extraction mechanism and a regulation and control mechanism, the multi-layer injection mechanism comprises an injection well, an injection allocation device and a two-way packer, the injection well vertically penetrates through 2-4 target reservoirs, and the injection allocation device vertically penetrates through the two-way packer; each target reservoir in the injection well is correspondingly provided with an injection allocation device and a two-way packer, each injection allocation device comprises a pressure sensor, a flow controller and a communication module, the collaborative extraction mechanism comprises a plurality of water production wells, the water production wells are arranged on the periphery of the injection well, and the two-way packers are arranged on the periphery of the injection well. Each water production well corresponds to one target reservoir, an adjustable water pumping screen pipe, a pressure feedback valve and a flow metering device are correspondingly arranged in each water production well, the regulation and control mechanism comprises a controller and an optical fiber monitoring device, and the controller is electrically connected with the optical fiber monitoring device, the pressure sensor, the flow metering device and the pressure feedback valve. The carbon sequestration CO2 multi-layer injection-production collaborative balance system provided by the invention has the advantages of high safety and high efficiency.

The invention discloses a coal underground gasification injection-production well pattern determination method, device and equipment and a medium. The method comprises the steps that an injection well site is determined according to a gasification control area of a target reservoir development body, and an injection well bore structure is determined according to injection conditions and coal seam parameters corresponding to the gasification control area; determining a migration path concentration area and an enrichment area of preset generated gas, and determining a production well site according to the migration path concentration area and the enrichment area of the preset generated gas; and according to the injection well site, the injection well body structure and the production well site, coal underground gasification injection-production well pattern distribution of the target reservoir development body is determined. According to the technical scheme, by selecting the proper injection well site, the injection well body structure and the production well site, coal underground gasification injection-production well pattern distribution is determined, coal underground gasification injection-production well pattern deployment is achieved, and the coal seam combustion rate and the preset generated gas recovery rate are increased.

The invention belongs to the technical field of coal bed gas exploitation, and particularly relates to an extraction system and method for high-pressure air blasting and hot flue gas displacement of coal bed gas. The system comprises a high-pressure air blasting unit, a hot flue gas injection unit, a gas extraction unit and a data monitoring unit, the high-pressure air blasting unit and the hot flue gas injection unit share the same blasting and gas injection well, an extraction well is arranged on the outer ring of the blasting and gas injection well, and the gas extraction unit extracts gas through the extraction well; the coal seam is subjected to fracturing and permeability increasing through high-pressure air blasting, the coal seam can be effectively fractured, and the permeability of the coal seam can be effectively improved; hot flue gas is injected after high-pressure air blasting permeability increasing is conducted on the coal seam, the hot flue gas can be smoothly injected into the coal seam, and the coal seam is further fractured; the temperature of the coal seam can be increased by injecting the hot flue gas, desorption and migration of CH4 are facilitated, meanwhile, CH4 in an adsorption state is replaced by CO2 by means of the adsorption characteristic of CO2, and CO2 is effectively sealed in the coal seam while the desorption amount of the coal seam gas is increased.

The application discloses an intelligent identification method for dominant seepage channels based on big data, which comprises the following steps: collecting static geological data, dynamic development data and dynamic monitoring data of an oil reservoir and performing data processing; performing data quality analysis on the processed data and establishing a sample database; performing inter-well connectivity analysis and inter-well pressure response analysis in a plane according to the sample database, and identifying dominant channels in the plane; performing interlayer production and absorption law research in a vertical direction according to the sample database, predicting interlayer liquid production and absorption ratios and water cut, and identifying dominant interlayer positions in the vertical direction; and comprehensively identifying dominant seepage channels between each layer of a production well and an injection well based on the identified dominant channels in the plane and the dominant interlayer positions in the vertical direction.

The invention provides a carbon dioxide injection well perforation parameter optimization method and device and electronic equipment, and the method comprises the steps: carrying out the standardization processing of geological and logging data, and constructing a multi-dimensional data set comprising lithology, porosity, permeability, crack parameters and a ground stress field; a three-dimensional digital twinborn model is constructed based on the data set, and reservoir heterogeneity and fracture network distribution are restored; on the basis of the digital twinborn model, performing multi-physics field coupling simulation including carbon dioxide migration simulation, shaft stress distribution simulation and long-term corrosion prediction; based on a multi-objective optimization algorithm, with the effective wave and volume of the carbon dioxide, the integrity coefficient of the shaft and the anti-channeling safety coefficient as objectives, an optimal perforation parameter combination is screened; and outputting a visual report including perforation parameters, simulation results and risk assessment. Digital twinning, multi-physics field simulation and multi-objective optimization are deeply fused, and a set of complete, accurate and efficient perforation parameter optimization solution from data to decision is formed.

The invention discloses a coal bed gas exploitation method for promoting microbial gasification synergy under the action of electric-magnetic double fields, and belongs to the technical field of coal bed gas exploitation. The method comprises the following steps: fracturing a coal reservoir through an injection well to form a fracture network; injecting an electrolyte solution and a microbial solution into the fracture network, wherein the microbial solution contains flora induction particles; applying an electric field to the coal reservoir, and controlling the flora of the microbial solution and flora-induced particles to migrate in the fracture network; then applying a low voltage field to promote further communication of branch fractures in the fracture network, and inducing migration again; applying a magnetic field to the coal reservoir; microorganism proliferation and uniform distribution are promoted, organic matter decomposition and methane release in the coal seam are accelerated, and the coal seam gas yield is increased.

A fluid monitoring system includes at least one injection wellbore formed from a terranean surface into a subterranean formation; a fluid injection assembly configured to circulate a fluid through the at least one injection wellbore and into the subterranean formation; at least one monitor wellbore formed from the terranean surface into or near the subterranean formation, where the at least one monitor wellbore is separated from the at least one injection wellbore by the subterranean formation; at least one acoustic energy source positioned in the at least one monitor wellbore and configured to emit acoustic energy from the at least one monitor wellbore into the subterranean formation; and at least one acoustic energy receiver positioned in the at least one monitor wellbore and configured to receive acoustic energy reflected from the fluid circulated into the subterranean formation to the at least one acoustic energy receiver.

Methods and systems for geothermal energy production wherein multiple horizontal or vertical wells may be used to pass fluids through the Earth from an injector well to a producer well through induced cracks, splits, fractures, conduits, or channels in the rock. Such methods and systems may include controlling tensile-split conduits in a subterranean geothermal formation by providing an injection well, providing a production well, configuring the injection well for injection of a tensile-splitting fluid into a production zone, configuring the production well to produce a heated fluid from the production zone, applying pressure to the production well, creating a plurality of tensile-split conduits, raising or lowering the pressure in the production well, establishing fluid communication between the injection well and the production well, and producing the heated fluid to the surface.

The invention discloses an active treatment method for multi-source residual coal gas of a waste mine, which comprises the following steps: firstly, hydraulic fracturing pressure relief permeability improvement and overlying strata separation layer grouting reinforcement are cooperated, the hydraulic fracturing pressure relief permeability improvement establishes a netted fracture network in a coal body to realize permeability improvement, and the overlying strata separation layer grouting reinforcement compacts goaf gangue through grouting and reinforces an overlying strata to form a continuous bearing consolidation body; and therefore, a pressure relief and permeability increasing-strengthening and reinforcing integrated structure is formed, a stable structure and a penetrating seepage network are provided for subsequent displacement and gas extraction, and the subsequent gas extraction efficiency is guaranteed. Then low-temperature liquid CO2 is injected into the coal seam through the injection well, gas displacement and desorption are conducted on gas adsorbed in the coal seam under the action of phase change and competitive adsorption, expansion and development are conducted on fractures to enable permeability to be secondarily enhanced, and meanwhile part of CO2 obtained after displacement is retained and sealed in a coal body and a goaf; on the premise that the gas extraction concentration and efficiency are effectively improved, CO2 can be stored, and the dual effects of resource utilization and carbon storage are achieved.

The invention discloses a deep coal supercritical water advancing type gasification method, which comprises the following steps that fracturing fluid is injected from an injection well, and negative pressure is formed in a production well, so that under the guidance of the negative pressure of the production well, the fracturing fluid is fractured in a coal seam to form a communication seam network between an output section of the injection well and an input section of the production well; supercritical water is injected into the coal seam from the injection well, so that part of the coal body of the coal seam is heated; oxygen is injected into the coal seam from the injection well, part of the coal body of the coal seam and the oxygen are subjected to an oxidation reaction to be heated, then part of the coal body of the coal seam, the supercritical water and the oxygen are subjected to an oxidation-reduction reaction to form a reaction area of the coal seam, and gas is generated; gas enters the production well through the communication seam net and is extracted through the production well; and the supercritical water and the oxygen are injected alternately and repeatedly until the reaction area of the coal seam is gradually propelled from the output section of the injection well to the input section of the production well through the communication seam net. According to the invention, the gas trapping efficiency, the total produced gas quantity and the resource utilization rate of the coal seam can be improved.

The invention provides a method and system of characterising at least one fracture 120, 122, 124 in an enhanced geothermal system. The method comprises arranging two or more tracer sources 150, 152, 1