Shale reservoir body cracking and carbon sequestration method and system

Abstract

The invention provides a shale reservoir body cracking and carbon sequestration method and system. Relates to the technical field of unconventional oil and gas exploitation and green shale gas yield increase. The method comprises the steps that a horizontal well of a target shale reservoir is divided into a plurality of packing section clusters, and in-situ methane in rock pores in the target packing section clusters is displaced and recycled by injecting a supercritical carbon dioxide carrier into the target packing section clusters; a gaseous reactant with a preset proportion is injected into the target packing section cluster, and the gaseous reactant and the supercritical carbon dioxide carrier form mixed fluid; the mixed fluid is triggered to be burnt and exploded through plasma jet, rock mineral lattices in the target packing section cluster are destroyed at the same time, and rock in-situ cracking is achieved through the cooperation of burning explosion fracturing and electric pulse fracturing; and after cracking is finished, by maintaining the supercritical carbon dioxide environment in the target packing section cluster, carbon dioxide generated in the cracking process is induced to be subjected to a mineralization reaction with a rock fracture surface formed by cracking, and the carbon dioxide is sealed in rock minerals.

Description

Technical Field

[0001] This invention relates to the field of unconventional oil and gas extraction and green production enhancement of shale gas, and in particular to a method and system for shale reservoir body pyrolysis and carbon sequestration. Background Technology

[0002] Shale gas, as an important unconventional natural gas resource, plays a crucial role in energy security and energy structure transformation through its efficient development. Hydraulic fracturing is currently the mainstream technology for shale reservoir stimulation, but it has inherent drawbacks such as huge water consumption, potential groundwater pollution, difficulties in handling flowback fluid, and the ability to form only a relatively simple main fracture network.

[0003] To overcome the above problems, existing technologies have proposed the idea of ​​using in-situ methane for combustion-explosion fracturing. Although this technology can reduce water consumption and form complex fractures, its combustion-explosion process has poor controllability and inaccurate energy release, which may lead to wellbore damage or excessive concentration of fractures in the near-wellbore area. Furthermore, the carbon dioxide and other gases produced after multiple combustion-explosions dilute the methane concentration, affecting the efficiency of subsequent combustion-explosions. Summary of the Invention

[0004] Therefore, it is necessary to provide a method and system for shale reservoir body pyrolysis and carbon sequestration to address the above-mentioned technical problems, so as to solve the defects of existing technologies, such as the difficulty in accurately controlling the release of combustion and explosion energy and the deterioration of the gas environment after multiple operations affecting the efficiency of subsequent combustion and explosion, and to realize the precise transformation and green development of shale reservoirs.

[0005] The following technical solution is adopted in this specification: This specification provides a method for shale reservoir body fracturing and carbon sequestration, including: The horizontal well of the target shale reservoir is divided into several isolation sections. By injecting supercritical carbon dioxide carrier into the target isolation sections, the in-situ methane in the rock pores of the target isolation sections is displaced and recovered. A predetermined proportion of gaseous reactant is injected into the target containment cluster, and the gaseous reactant and supercritical carbon dioxide carrier form a mixed fluid; The plasma jet ignites the mixed fluid combustion and simultaneously destroys the rock and mineral lattice within the target containment cluster, achieving in-situ rock fracturing through the synergistic effect of combustion-explosive fracturing and electric pulse fracturing. After pyrolysis, by maintaining a supercritical carbon dioxide environment within the target septum cluster, the carbon dioxide generated during the pyrolysis process is induced to undergo a mineralization reaction with the rock fracture surfaces formed by pyrolysis, thereby sequestering the carbon dioxide in the rock minerals.

[0006] Furthermore, acoustic signals, strain data, and temperature parameters are collected along the entire length of the horizontal wellbore using pre-set distributed optical fibers. Based on the collected acoustic signals, strain data and temperature parameters, the three-dimensional stress field distribution characteristics and rock mechanical parameters of the target shale reservoir were inverted. Based on the three-dimensional stress field distribution characteristics and rock mechanical parameters, the location, range and characteristics of the heterogeneous region of the target shale reservoir are dynamically identified. Based on the location, range and characteristics of the heterogeneous region, the horizontal well of the target shale reservoir is divided into several isolation section clusters.

[0007] Furthermore, the injection of a predetermined proportion of gaseous reactant into the target containment cluster specifically includes: Based on the three-dimensional stress field distribution characteristics, rock mechanical parameters, and residual methane concentration in the target shale reservoir, the injection ratio of gaseous reactant is obtained, and a preset ratio of gaseous reactant is injected into the target shale reservoir according to the ratio. The gaseous reactant includes oxygen and ozone, wherein ozone acts as a reaction enhancer to lower the ignition energy threshold of the plasma jet, thereby making the combustion process controllable.

[0008] Furthermore, the in-situ rock fracturing process extends along a pre-defined fracture flow channel, which is a network of directional flow channels formed by injecting or imprinting biodegradable polymer composite materials into the wellbore of a horizontal well in the target shale reservoir to guide rock fracturing growth in a predetermined direction; wherein, the biodegradable polymer composite material is adapted to the temperature and pressure conditions of different packer clusters and completes degradation within a predetermined time.

[0009] Furthermore, while the supercritical carbon dioxide carrier displaces the in-situ methane in the rock pores within the target containment cluster, it also utilizes the low-temperature characteristics of the supercritical carbon dioxide carrier to cool the target containment cluster, thereby reducing the risk of thermal damage from pyrolysis.

[0010] Furthermore, it also includes: Based on the crack propagation morphology, temperature and pressure changes, and mineralization reaction intensity of the target containment cluster, the supercritical carbon dioxide injection rate, gaseous reactant ratio, and plasma energy parameters of the next target containment cluster are dynamically adjusted.

[0011] This specification provides a shale reservoir fracturing and carbon sequestration system, characterized by including a surface control module, a downhole execution module, and a data feedback module; The ground control module includes: a supercritical carbon dioxide injection and pressurization unit, an oxygen / ozone mixing generator, a high-frequency pulsed plasma power supply, an industrial gas extraction and methane separation and recovery unit, and an intelligent adaptive control unit. The downhole execution module is configured to be run into a horizontal well via coiled tubing and includes: a biodegradable flow channel construction tool, a smart packer, a distributed fiber optic sensing unit, a supercritical carbon dioxide injection valve, a reactant injection valve, and a high-frequency pulsed plasma generator. The data feedback module is configured to collect downhole acoustic wave, strain and temperature data in real time through the distributed optical fiber sensing unit, and upload the collected data to the intelligent adaptive control unit. The intelligent adaptive control unit is used to adaptively adjust the operating parameters of the ground control module and the downhole execution module based on the received data, so as to form a closed-loop intelligent control.

[0012] Furthermore, the intelligent adaptive control unit is configured as follows: The system receives monitoring data from the distributed optical fiber sensing unit and divides the received monitoring data into isolation segment clusters. The supercritical carbon dioxide injection and pressurization unit and the supercritical carbon dioxide injection valve are controlled to inject supercritical carbon dioxide into the target cluster to displace in-situ methane and recover it through the industrial extraction and methane separation and recovery unit. Based on the methane concentration data, the oxygen / ozone generator and the reactant injection valve are controlled to inject a customized ratio of oxygen-ozone mixture; The high-frequency pulsed plasma power supply is controlled to excite the high-frequency pulsed plasma generator; And based on the full-process data fed back by the distributed optical fiber sensing unit, the operating parameters of the next target isolation segment cluster are adaptively optimized.

[0013] The above-mentioned technical solutions adopted in this specification can achieve the following beneficial effects: This invention eliminates the dependence on uncontrollable methane concentrations within the formation by injecting supercritical carbon dioxide carrier into the target containment cluster and replacing in-situ methane. Simultaneously, it utilizes a pre-defined proportion of gaseous reactants to construct a precisely controllable mixed fluid system, solving the efficiency degradation and uncontrollable energy release problems caused by the deterioration of the gas environment in traditional in-situ combustion explosions. Furthermore, it introduces a plasma jet as a high-energy ignition source, using its electrical pulse shock wave to pre-damage the rock and synergize with the combustion energy of the mixed fluid. This achieves a leap from simple "physical fracturing" to in-situ fracturing coupled with a "thermo-mechanical-chemical" approach, enabling precise control of fracture extension direction and effectively avoiding excessive energy concentration in the near-wellbore zone. This invention exposes fresh rock fractures rich in highly reactive metal ions such as calcium, magnesium, and iron by disrupting the rock mineral lattice, providing a sufficient material basis for mineralization reactions. Maintaining a supercritical carbon dioxide environment not only utilizes its combination of high gas diffusivity and high liquid solubility to rapidly penetrate into micro-nano pores and dissolve rock components, but also creates an acidic environment in the presence of trace amounts of water to accelerate ion dissolution. This perfect match of high temperature and pressure, supercritical mass transfer, and fresh fractures significantly reduces the reaction energy barrier, inducing carbon dioxide to rapidly combine with metal ions on the rock surface to form stable carbonate minerals. This achieves efficient conversion and sequestration from gaseous to solid state, avoiding any impact on subsequent reactions. Attached Figure Description

[0014] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments of this application and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0015] Figure 1 This is one of the flowcharts illustrating a shale reservoir body pyrolysis and carbon sequestration method provided in this specification; Figure 2 This is the second flowchart illustrating a shale reservoir fracturing and carbon sequestration method provided in this specification. Figure 3 This manual provides a schematic diagram of the surface and downhole operations of an integrated collaborative production enhancement system. Figure 4 This specification provides a schematic diagram of a downhole operation profile for intelligent segment cluster division and plasma excitation. Figure 5 This is a schematic diagram of an intelligent responsive three-dimensional crack network provided in this specification. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of this specification clearer, the technical solutions of this application will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments in this specification without creative effort are within the scope of protection of this application.

[0017] The following is combined Figures 1-2 The present invention describes a method for shale reservoir body pyrolysis and carbon sequestration.

[0018] Figure 1 This is one of the flowcharts illustrating a shale reservoir body fracturing and carbon sequestration method provided in this specification, such as... Figure 1 As shown, the method includes the following: S101. Divide the horizontal well of the target shale reservoir into several packer clusters. By injecting supercritical carbon dioxide carrier into the target packer clusters, displace and recover the in-situ methane in the rock pores within the target packer clusters.

[0019] Among them, the supercritical carbon dioxide carrier displaces the in-situ methane in the rock pores within the target containment cluster while simultaneously cooling the target containment cluster using the low-temperature characteristics of the supercritical carbon dioxide carrier, thereby reducing the risk of thermal damage from plasma pyrolysis.

[0020] For example, the specific process of dividing a horizontal well in a target shale reservoir into several clusters of containment sections can be achieved using a distributed fiber optic sensing system. Specifically, a distributed fiber optic sensing system is permanently deployed along the completion string to collect and transmit acoustic signals, strain data, and temperature parameters across the entire length of the horizontal wellbore in real time. The intelligent algorithm at the ground control center receives this data and, based on the collected acoustic signals, strain data, and temperature parameters, inverts the three-dimensional stress field distribution characteristics and rock mechanical parameters of the target shale reservoir. This inversion can be data-driven or mechanism-driven, and the appropriate method can be flexibly selected based on the actual conditions such as the quality of on-site data, geological complexity, and engineering accuracy requirements. This embodiment does not impose a single limitation on the specific inversion method. Based on the three-dimensional stress field distribution characteristics and rock mechanics parameters obtained by inversion, the location, range and characteristics of heterogeneous regions in the target shale reservoir (such as stress concentration areas or brittle areas) are dynamically identified, and the setting position of the packer is optimized accordingly. Based on the location, range and characteristics of the heterogeneous regions, the horizontal wells of the target shale reservoir are divided into several packer clusters, thereby forming a non-uniform intelligent cluster division and improving the targeting of reservoir stimulation.

[0021] S102. Inject a preset proportion of gaseous reactant into the target sealing segment cluster, and the gaseous reactant and supercritical carbon dioxide carrier form a mixed fluid.

[0022] For example, injecting a predetermined proportion of gaseous reactant into the target containment cluster is a dynamic process based on real-time data analysis. Based on the three-dimensional stress field distribution characteristics, rock mechanical parameters, and residual methane concentration in the target shale reservoir, the optimal injection ratio of the gaseous reactant is dynamically calculated and obtained. The reactant injection valve is then controlled to inject the predetermined proportion of gaseous reactant into the target containment cluster. The gaseous reactant consists of a mixture of oxygen and ozone. Ozone acts as a reaction enhancer, lowering the ignition energy threshold of the subsequent plasma jet, making the combustion process more gentle and controllable, thereby achieving low-energy, high-safety in-situ pyrolysis operations.

[0023] S103. The mixed fluid is ignited by plasma jet, and the rock mineral lattice in the target isolation section cluster is destroyed at the same time, so as to achieve in-situ rock pyrolysis in synergy between combustion-explosive fracturing and electric pulse fracturing.

[0024] For example, plasma jets induce combustion and explosion of the mixed fluid, synergistically disrupting the rock and mineral lattice within the target containment cluster. This achieves in-situ rock fracturing through a combination of combustion-explosive fracturing and electrical pulse fracturing. Specifically, a plasma jet is introduced as a high-energy ignition source, utilizing its electrical pulse shock wave to pre-damage the rock lattice and coordinate with the combustion and explosion energy of the mixed fluid. This mechanism represents a leap from simple "physical fracturing" to in-situ fracturing coupled with "thermo-mechanical-chemical" processes, enabling precise control of fracture propagation direction and effectively avoiding wellbore damage caused by excessive energy concentration in the near-wellbore zone.

[0025] For example, the in-situ fracturing process of rock extends along pre-defined fracture guidance channels. These channels are a network of directional guidance channels formed by injecting or imprinting biodegradable polymeric composite materials (such as PLA or PGA) onto the wellbore of a horizontal well in the target shale reservoir using a biodegradable guidance channel construction tool. The biodegradable polymeric composite material is adaptable to the temperature and pressure conditions of different packer clusters and undergoes controlled degradation within a predetermined time, with the degradation products causing no contamination to the reservoir.

[0026] S104. After the pyrolysis is completed, by maintaining the supercritical carbon dioxide environment within the target sealing segment cluster, the carbon dioxide generated during the pyrolysis process is induced to undergo a mineralization reaction with the rock fracture surface formed by the pyrolysis, thereby sealing the carbon dioxide in the rock minerals.

[0027] For example, the mineralization reaction mechanism during the cracking process is as follows: By disrupting the rock mineral lattice, fresh rock fracture surfaces rich in highly reactive metal ions such as calcium, magnesium, and iron are exposed, providing a sufficient material basis for the mineralization reaction. Simultaneously, maintaining a supercritical carbon dioxide environment not only utilizes its combination of high gas diffusivity and high liquid solubility to rapidly penetrate into micro- and nano-pores and dissolve rock components, but also creates an acidic environment in the presence of trace amounts of water, accelerating ion dissolution. This perfect match of high temperature and pressure, supercritical mass transfer, and fresh fracture surfaces significantly lowers the reaction energy barrier, inducing carbon dioxide to rapidly combine with metal ions on the rock surface to form stable carbonate minerals. This achieves efficient conversion and sequestration from gaseous to solid state, avoiding impact on subsequent reactions, and supporting and modifying the fracture surface.

[0028] In addition, this method can intelligently optimize subsequent operations based on the fracture propagation morphology, temperature and pressure changes, and mineralization reaction intensity of the target containment cluster. Specifically, the entire process data, including fracture extension length, orientation, and mineralization reaction rate, monitored by distributed fiber optic sensing units during the previous target containment cluster operation, is used as a training set and input into the machine learning algorithm of the intelligent adaptive control center. This algorithm can learn and predict the reservoir response to fracturing in the next target containment cluster based on the training set. Based on the reservoir response to fracturing in the next target containment cluster, the system dynamically adjusts the operational parameters of the next target containment cluster, including the supercritical carbon dioxide injection rate, ozone mixing ratio, and plasma pulse frequency and energy, thereby forming a closed-loop intelligent control and gradually optimizing the final fracture network effect.

[0029] This invention utilizes biodegradable materials such as PLA (polylactic acid) and PGA (polyglycolic acid) to construct pre-formed fracture guidance channels within horizontal wells; it employs a distributed fiber optic sensing system to monitor the three-dimensional stress and temperature fields of the horizontal well section in real time and intelligently divides it into isolation clusters; it injects supercritical carbon dioxide carriers into the target clusters to displace and extract in-situ methane while simultaneously cooling the reservoir; it injects a customized proportion of gaseous reactants into the supercritical carbon dioxide environment; and it uses a downhole high-frequency pulsed plasma generator to excite the mixed fluid, achieving low-energy, controllable combustion and in-situ rock fracturing; after the combustion, it maintains a supercritical carbon dioxide-dominated environment to induce a mineralization reaction between the fractured carbon and carbon dioxide, achieving carbon fixation and fracture surface modification; and it adaptively adjusts operating parameters based on real-time monitoring data, ultimately forming an intelligent responsive fracture network. Plasma fracturing is a reservoir stimulation technology that combines high-energy physics and plasma chemistry. It no longer relies on ordinary explosions but rather a more precise and controllable destructive method. Through the synergistic effect of physical fracturing and chemical pyrolysis, it can create a more complex and efficient fracture network in shale, while simultaneously creating favorable conditions for subsequent carbon sequestration. This is one of the key technologies for achieving green and efficient shale gas development. This invention achieves integrated synergy of precise energy release, carbon dioxide geological sequestration, and reservoir stimulation during shale gas extraction. By intelligently learning and optimizing fracturing parameters, it significantly improves fracture complexity and conductivity, and realizes green negative carbonization in shale gas development. It has the following effects:

[0030] 1. Precise and controllable energy release: High-frequency pulsed plasma is used as the excitation source, which enables precise control of the timing, location and intensity of combustion and explosion. Combined with the direct disintegration effect of the electric pulse, a synergistic fracturing effect is formed, avoiding energy waste and wellbore damage. The initiation and propagation of fractures are more controllable.

[0031] 2. Green negative carbonization operation: Innovatively using supercritical carbon dioxide as the main working fluid, it not only efficiently displaces methane and cools the reservoir, but also utilizes it to undergo a mineralization reaction with the fracture surface of fresh rock after fracturing, permanently sealing the carbon dioxide generated during the operation and the externally injected carbon dioxide underground, realizing the "negative carbon" or "low carbon" development of shale gas.

[0032] 3. Intelligent and Adaptive: A reservoir "digital twin" is constructed through a distributed fiber optic sensing system throughout the wellbore, enabling real-time, all-around perception of the fracturing process. Based on this, artificial intelligence algorithms can adaptively adjust the operational parameters of subsequent clusters, upgrading the reservoir stimulation strategy from "experience-driven" to "data and model-driven," ultimately forming an "intelligent responsive" three-dimensional fracture network highly matched to the reservoir's heterogeneity, maximizing single-well production and final recovery rate.

[0033] 4. Integrated Synergistic Efficiency: This invention organically integrates the three originally independent processes of "reservoir stimulation", "energy extraction" and "carbon sequestration" into a continuous and synergistic closed-loop system. While increasing shale gas production, it significantly reduces the environmental footprint, representing the cutting-edge direction of the next generation of green and efficient development of unconventional oil and gas.

[0034] Figure 2 This is the second flowchart illustrating a shale reservoir body fracturing and carbon sequestration method provided in this specification. Figure 2 As shown, the method also includes: S1. Constructing pre-formed fracture diversion channels within horizontal wells using biodegradable materials. This includes:

[0035] The biodegradable flow channel construction device is transported to the target section of the horizontal well via coiled tubing. The device forms a pre-installed flow channel network made of biodegradable polymer composite material on the shale reservoir of the wellbore through injection or imprinting. The biodegradable material degrades after a set time under reservoir temperature and pressure conditions, and the degradation products do not pollute the reservoir.

[0036] S2. Real-time three-dimensional stress and temperature field monitoring of the horizontal well section is performed using a distributed fiber optic sensing system, and the sealing section clusters are intelligently divided based on the monitoring data. This includes:

[0037] A distributed fiber optic sensing system is permanently deployed along the completion string to collect and transmit acoustic, strain, and temperature data of the entire wellbore in real time. Based on the data, the three-dimensional stress field and rock mechanics parameters of the reservoir are inverted through the intelligent algorithm of the ground control center, the regions with strong and weak heterogeneity of the reservoir are dynamically identified, and the setting position of the packer is optimized accordingly, forming a non-uniform intelligent segment cluster division.

[0038] S3. Inject supercritical carbon dioxide carrier into the target cluster to displace and extract in-situ methane, while simultaneously cooling the reservoir. This includes:

[0039] Supercritical carbon dioxide is injected into the target cluster through a closed injection system consisting of coiled tubing and packers. The low viscosity and high diffusivity of supercritical carbon dioxide effectively displace in-situ methane in the fractures and is recovered through the extraction system. At the same time, the low temperature characteristics of supercritical carbon dioxide cool the reservoir and reduce the risk of thermal damage from subsequent plasma pyrolysis.

[0040] S4. Inject a customized proportion of gaseous reactants into a supercritical carbon dioxide-dominated environment. This includes:

[0041] Based on the reservoir characteristics and remaining methane concentration obtained from real-time inversion, the required proportion of gaseous reactant is dynamically calculated. The gaseous reactant is a mixture of oxygen and ozone, in which ozone acts as a reaction enhancer to lower the energy threshold of subsequent plasma ignition and make the combustion process more gentle and controllable.

[0042] S5. A downhole high-frequency pulsed plasma generator is used to excite the mixed fluid, achieving low-energy controlled combustion and in-situ rock fracturing. This includes:

[0043] By using a downhole high-frequency pulsed plasma generator, a short-duration, high-energy electrical pulse is applied to the mixed fluid to generate a plasma jet. The plasma jet first induces the controlled combustion and explosion of the methane-fuel mixture, and its high-energy electrons simultaneously act directly on the rock and mineral lattice, producing an in-situ fracturing effect, thus achieving the synergy of "electric pulse fracturing" and "combustion and explosion fracturing".

[0044] S6. After combustion and explosion, maintaining a supercritical carbon dioxide-dominated environment induces a mineralization reaction between cracked carbon and carbon dioxide, achieving carbon fixation and fracture surface modification. This includes:

[0045] After combustion-explosion fracturing, the pressure within the well section is maintained through the injection system, keeping the environment in a supercritical carbon dioxide state. The fresh rock fracture surface and high reactivity generated by the combustion-explosion promote the supercritical carbon dioxide to react with calcium, magnesium and other cations in the rock to undergo carbonate mineralization, generating stable carbonate minerals, achieving permanent carbon dioxide sequestration and supporting and modifying the fracture surface.

[0046] S7. Based on real-time monitoring data, adaptively adjust the operating parameters of S3-S6 and optimize the operation of subsequent segment clusters, ultimately forming an intelligent responsive three-dimensional fracture network in the horizontal well. S7 includes:

[0047] The distributed fiber optic sensing system in S2 monitors the crack propagation morphology, temperature and pressure changes, and mineralization reaction intensity in real time during processes S5 and S6. The data is transmitted to the ground control center in real time, where it is analyzed by an adaptive learning algorithm. The algorithm then dynamically adjusts the supercritical carbon dioxide injection amount, reactant ratio, and plasma energy parameters of the next cluster segment to form a closed-loop intelligent control, gradually optimizing the final crack network effect.

[0048] The following is combined Figures 3-5 The present invention describes a shale reservoir body pyrolysis and carbon sequestration system.

[0049] This specification also provides a shale reservoir body fracturing and carbon sequestration system, which includes a surface control module, a downhole execution module, and a data feedback module.

[0050] The ground control module includes: a supercritical carbon dioxide injection and pressurization unit, an oxygen / ozone mixing generator, a high-frequency pulsed plasma power supply, an industrial gas extraction and methane separation and recovery unit, and an intelligent adaptive control unit.

[0051] The downhole execution module is configured to be run into a horizontal well via coiled tubing and includes: a biodegradable flow channel construction tool, a smart packer, a distributed fiber optic sensing unit, a supercritical carbon dioxide injection valve, a reactant injection valve, and a high-frequency pulsed plasma generator.

[0052] The data feedback module is configured to collect real-time acoustic, strain, and temperature data from downhole via distributed fiber optic sensing units and upload the collected data to the intelligent adaptive control unit. The intelligent adaptive control unit is used to adaptively adjust the operating parameters of the surface control module and the downhole execution module based on the received data, thus forming a closed-loop intelligent control system.

[0053] The intelligent adaptive control unit is configured to: receive monitoring data from the distributed fiber optic sensing unit and divide the containment clusters according to the received monitoring data; control the supercritical carbon dioxide injection and pressurization unit and the supercritical carbon dioxide injection valve to inject supercritical carbon dioxide into the target clusters to displace in-situ methane and recover it through the industrial extraction and methane separation and recovery unit; control the oxygen / ozone mixer generator and the reactant injection valve to inject a customized ratio of oxygen-ozone mixture according to the methane concentration data; control the high-frequency pulsed plasma power supply to excite the high-frequency pulsed plasma generator; and adaptively optimize the operating parameters of the next target containment cluster based on the full-process data fed back by the distributed fiber optic sensing unit.

[0054] Figure 3 This manual provides a schematic diagram of the surface and downhole operations of an integrated collaborative production enhancement system, as shown below. Figure 3 As shown, the surface section is centered around the data feedback center located in the upper right of the diagram and the plasma power source located next to the data feedback center. It is responsible for receiving and processing monitoring data and issuing operation commands. The optical fiber extends downward from the control center along the underground horizontal well shaft to collect and transmit downhole acoustic, strain, and temperature data in real time. At the same time, the surface section also includes the carbon dioxide storage tank, oxygen-ozone mixer generator, supercritical carbon dioxide pressurization center, reactant injection valve, and delivery pipelines connecting the various devices, as shown in the upper left of the diagram. The carbon dioxide storage tank is used to provide supercritical carbon dioxide carrier, the oxygen-ozone mixer generator prepares gaseous reactant, and the reactant injection valve precisely controls the amount of reactant injected. The downhole section uses the underground horizontal well penetrating the shale reservoir as the main operating channel. Carbon dioxide is pressurized to a supercritical state and then injected into the horizontal well. The horizontal well is divided into several packer clusters. Figure 4This specification provides a schematic diagram of a downhole operation profile for intelligent cluster division and plasma excitation. Within the horizontal wellbore, an intelligent packer intelligently divides the reservoir into several independent packer clusters, and a high-frequency pulsed plasma generator is deployed in each target cluster. Driven by a plasma power source, the generator applies short-duration high-energy electrical pulses to a mixture of supercritical carbon dioxide carrier and gaseous reactant to generate a plasma jet, inducing controlled combustion and explosion of the mixture. This, combined with the electrical pulse shock wave, causes in-situ fracturing of the shale reservoir. Simultaneously, distributed fiber optic sensing units collect real-time acoustic, strain, and temperature data from downhole and feed them back to the surface. Based on the monitoring data, operational parameters are adaptively adjusted to achieve precise shale reservoir modification and carbon sequestration in synergy. Figure 3 and Figure 4 As shown, during operation, a biodegradable flow channel is first constructed using a biodegradable flow channel construction tool. Then, distributed fiber optic sensing units are deployed and a smart packer is set up. The intelligent adaptive control unit divides the first optimal segment cluster based on initial monitoring data. Next, the supercritical carbon dioxide injection and pressurization unit is activated, injecting supercritical carbon dioxide through the supercritical carbon dioxide injection valve to displace in-situ methane, which is then recovered by the industrial extraction and methane separation and recovery unit. Based on methane concentration sensor data, the intelligent adaptive control unit directs the oxygen / ozone generator to inject a customized ratio of oxygen-ozone mixture through the reactant injection valve. Then, the high-frequency pulsed plasma power supply is activated, exciting the high-frequency pulsed plasma generator to achieve controlled combustion and rock fracturing. After combustion, the supercritical carbon dioxide environment is maintained to promote mineralization reactions. The distributed fiber optic sensing units provide real-time feedback of the entire process data, and the intelligent adaptive control unit uses this data for deep learning to optimize all parameters for the next segment cluster, repeating the process until an ideal three-dimensional fracture network is formed. Figure 5 This specification provides a schematic diagram of a smart responsive three-dimensional crack network, such as... Figure 5 As shown, when the high-frequency pulsed plasma power source on the ground provides energy to the high-frequency pulsed plasma generators downhole, these generators will generate a large number of complex fractures that are intertwined and extend to the far-well zone in the shale reservoir around the horizontal wellbore through the synergistic effect of controlled combustion and electrical pulse fracturing. This will eventually form a smart responsive three-dimensional fracture network with a wide coverage and good connectivity. This network breaks through the limitation of traditional hydraulic fracturing, which can only form a relatively simple main fracture network. It significantly improves the complexity and conductivity of fractures, and maximizes the production of a single well and the final recovery rate.

[0055] For example, the intelligent adaptive control unit incorporates a machine learning algorithm. When processing the first cluster, preset baseline parameters are used. Data such as fracture extension length, orientation, and mineralization reaction rate monitored by the distributed fiber optic sensing unit are used as the training set input to the algorithm. When processing the second and subsequent clusters, the algorithm can predict the reservoir's response to fracturing and adjust the supercritical carbon dioxide injection rate, ozone mixing ratio, and plasma pulse frequency and energy in advance, thereby achieving the effect of "becoming smarter and more effective with increasing fracturing intensity."

[0056] Specific limitations regarding shale reservoir fracturing and carbon sequestration systems can be found in the above description of shale reservoir fracturing and carbon sequestration methods, and will not be repeated here. Each module in the aforementioned shale reservoir fracturing and carbon sequestration system can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in or independent of the processor in a computer device, or stored in the computer device's memory as software, allowing the processor to call and execute the corresponding operations of each module.

[0057] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, storage, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, or optical storage, etc. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc.

[0058] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

Claims

1. A method for pyrolysis and carbon sequestration of shale reservoirs, characterized in that, include: The horizontal well of the target shale reservoir is divided into several isolation sections. By injecting supercritical carbon dioxide carrier into the target isolation sections, the in-situ methane in the rock pores of the target isolation sections is displaced and recovered. A predetermined proportion of gaseous reactant is injected into the target containment cluster, and the gaseous reactant and supercritical carbon dioxide carrier form a mixed fluid; The plasma jet ignites the mixed fluid combustion and simultaneously destroys the rock and mineral lattice within the target containment cluster, achieving in-situ rock fracturing through the synergistic effect of combustion-explosive fracturing and electric pulse fracturing. After pyrolysis, by maintaining a supercritical carbon dioxide environment within the target septum cluster, the carbon dioxide generated during the pyrolysis process is induced to undergo a mineralization reaction with the rock fracture surfaces formed by pyrolysis, thereby sequestering the carbon dioxide in the rock minerals.

2. The method for shale reservoir fracturing and carbon sequestration according to claim 1, characterized in that, The division of the horizontal wells in the target shale reservoir into several clusters of containment sections specifically includes: Acoustic signals, strain data, and temperature parameters are collected along the entire length of the horizontal wellbore using a pre-set distributed optical fiber. Based on the collected acoustic signals, strain data and temperature parameters, the three-dimensional stress field distribution characteristics and rock mechanical parameters of the target shale reservoir were inverted. Based on the three-dimensional stress field distribution characteristics and rock mechanics parameters, the location, extent, and characteristics of heterogeneous regions in the target shale reservoir are dynamically identified. Based on the location, extent, and characteristics of the heterogeneous regions, the horizontal wells of the target shale reservoir are divided into several isolation clusters.

3. The method for shale reservoir pyrolysis and carbon sequestration according to claim 2, characterized in that, The injection of a predetermined proportion of gaseous reactant into the target containment cluster specifically includes: Based on the three-dimensional stress field distribution characteristics, rock mechanical parameters, and residual methane concentration in the target shale reservoir, the injection ratio of gaseous reactant is obtained, and a preset ratio of gaseous reactant is injected into the target shale reservoir according to the ratio. The gaseous reactant includes oxygen and ozone, wherein ozone acts as a reaction enhancer to lower the ignition energy threshold of the plasma jet, thereby making the combustion process controllable.

4. The method for shale reservoir fracturing and carbon sequestration according to claim 1, characterized in that, The in-situ rock fracturing process extends along a pre-defined fracture flow channel. This fracture flow channel is a network of directional flow channels formed by injecting or imprinting biodegradable polymer composite materials into the wellbore of a horizontal well in the target shale reservoir. The biodegradable polymer composite material is adapted to the temperature and pressure conditions of different packer clusters and completes degradation within a pre-defined time.

5. The method for shale reservoir body fission and carbon sequestration according to claim 1, characterized in that, The supercritical carbon dioxide carrier displaces in-situ methane in the rock pores within the target containment cluster while simultaneously cooling the target containment cluster using its low-temperature properties, thereby reducing the risk of thermal damage from pyrolysis.

6. The method for shale reservoir body fission and carbon sequestration according to claim 1, characterized in that, Also includes: Based on the crack propagation morphology, temperature and pressure changes, and mineralization reaction intensity of the target containment cluster, the supercritical carbon dioxide injection rate, gaseous reactant ratio, and plasma energy parameters of the next target containment cluster are dynamically adjusted.

7. The method for shale reservoir body fission and carbon sequestration according to claim 6, characterized in that, The dynamic adjustment of the supercritical carbon dioxide injection rate, gaseous reactant ratio, and plasma energy parameters of the next target containment cluster specifically includes: The fracture extension length, orientation, and mineralization reaction rate data monitored by the distributed optical fiber sensing unit during the operation of the previous target containment cluster are used as the training set and input into the machine learning algorithm to predict the reservoir response to fracturing in the next target containment cluster. Based on the response of the next target containment cluster reservoir to fracturing, the supercritical carbon dioxide injection rate, ozone mixing ratio, and plasma pulse frequency and energy are adjusted.

8. A shale reservoir body fracturing and carbon sequestration system based on shale reservoir body fracturing and carbon sequestration methods, characterized in that, It includes a ground control module, a downhole execution module, and a data feedback module; The ground control module includes: a supercritical carbon dioxide injection and pressurization unit, an oxygen / ozone mixing generator, a high-frequency pulsed plasma power supply, an industrial gas extraction and methane separation and recovery unit, and an intelligent adaptive control unit. The downhole execution module is configured to be run into a horizontal well via coiled tubing and includes: a biodegradable flow channel construction tool, a smart packer, a distributed fiber optic sensing unit, a supercritical carbon dioxide injection valve, a reactant injection valve, and a high-frequency pulsed plasma generator. The data feedback module is configured to collect downhole acoustic wave, strain and temperature data in real time through the distributed optical fiber sensing unit, and upload the collected data to the intelligent adaptive control unit. The intelligent adaptive control unit is used to adaptively adjust the operating parameters of the ground control module and the downhole execution module based on the received data, so as to form a closed-loop intelligent control.

9. A shale reservoir fracturing and carbon sequestration system based on claim 8, characterized in that, The intelligent adaptive control unit is configured as follows: The system receives monitoring data from the distributed optical fiber sensing unit and divides the received monitoring data into isolation segment clusters. The supercritical carbon dioxide injection and pressurization unit and the supercritical carbon dioxide injection valve are controlled to inject supercritical carbon dioxide into the target cluster to displace in-situ methane and recover it through the industrial extraction and methane separation and recovery unit. Based on the methane concentration data, the oxygen / ozone generator and the reactant injection valve are controlled to inject a customized ratio of oxygen-ozone mixture; The high-frequency pulsed plasma power supply is controlled to excite the high-frequency pulsed plasma generator; And based on the full-process data fed back by the distributed optical fiber sensing unit, the operating parameters of the next target isolation segment cluster are adaptively optimized.

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