CO2 heating and fracturing stimulation system and method based on capillary tube bundle network

Abstract

The invention belongs to the technical field of energy and oil-gas field development, and particularly relates to a CO2 heating and fracturing yield increasing system and method based on a capillary tube bundle net, the CO2 heating and fracturing yield increasing system comprises a compressor, an injection well and a horizontal well which are connected in sequence, and the horizontal well is in a yield decline period; a capillary tube bundle net is arranged on the side wall of the horizontal well and comprises a plurality of main tubes and a plurality of branch capillary tube bundles, and the main tubes are parallel to the axial direction of the horizontal well and evenly distributed in the annular direction of the horizontal well. The plurality of branch capillary tube bundles are connected between two adjacent main tubes to form a capillary tube bundle net; the main pipe and the branch capillary bundles are made of corrosion-resistant and high-temperature-resistant alloy materials; the capillary tube bundle net is connected with a ground power supply system, and the capillary tube bundle net is powered on and used for heating CO2. The problems that in the prior art, traditional CO2 fracturing fluidity is poor, crack propagation is limited, and crude oil displacement efficiency is low can be effectively solved.

Description

Technical Field

[0001] This invention belongs to the field of energy and oil and gas field development technology, specifically relating to a CO2 heating and fracturing production enhancement system and method based on capillary bundle network. Background Technology

[0002] The statements herein provide only background information in relation to this invention and do not necessarily constitute prior art.

[0003] In the field of unconventional oil and gas resource development, how to maximize the development of shale oil reservoirs has always been a challenge. Although the application of horizontal wells and hydraulic fracturing technology has achieved initial breakthroughs in shale oil production, its primary oil recovery rate is low, and a large portion of crude oil remains underground due to deficiencies in extraction technology, resulting in resource waste. Currently, secondary oil recovery or enhanced oil recovery technologies for shale oil, such as water injection and gas injection, are either ineffective due to poor reservoir permeability or have low economic feasibility due to high costs, and no universally applicable solution has yet emerged.

[0004] Carbon dioxide enhanced oil recovery (CO2-IF) technology is considered a potential method for improving oil recovery. However, the discrete injection method, which involves preheating CO2 to a sufficient temperature, still results in a significant drop in CO2 temperature and an increase in viscosity during injection. This leads to insufficient CO2 flowability and rock penetration, limited fracture propagation, poor connectivity, and low fracturing efficiency. Secondly, its function is singular, with its core objective being solely to increase crude oil production, failing to synergize with a broader energy system and asset functions. Finally, although the process can sequester some carbon dioxide, under the single objective of increasing production, its sequestration benefits are often considered a secondary byproduct, making it difficult to form an effective closed loop of carbon emission reduction benefits. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the purpose of this invention is to provide a CO2 heating and fracturing production enhancement system and method based on capillary bundle networks. This system aims to overcome the problems of poor fluidity, limited fracture propagation, low crude oil displacement efficiency, insufficient utilization of carbon dioxide resources, high operating costs, and limited energy storage facility site selection and significant energy loss in traditional CO2 fracturing technologies. The invention constructs an integrated system of "capillary bundle network synchronous CO2 heating and injection + U-shaped circulating well network + closed-loop CO2 utilization," providing a new solution for efficient shale oil extraction, carbon emission reduction, and energy recycling.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solution: In a first aspect, the present invention provides a CO2 heating and fracturing production enhancement system based on a capillary bundle network, comprising a compressor, an injection well and a horizontal well connected in sequence, wherein the horizontal well is in a production decline period; The horizontal well is provided with a capillary bundle network on its sidewall. The capillary bundle network includes several main tubes and several branch capillary bundles. The main tubes are parallel to the axial direction of the horizontal well and are evenly distributed along the circumferential direction of the horizontal well. Several branch capillary bundles are connected between two adjacent main tubes to form a capillary bundle network; Both the main tube and the branch capillary bundles are made of corrosion-resistant, high-temperature-resistant nickel-chromium-molybdenum-niobium alloy material; The capillary bundle is connected to the ground power supply system, and electricity is supplied to the capillary bundle to heat CO2.

[0007] Secondly, the present invention provides a method for CO2 heating and fracturing enhancement based on capillary bundle networks, comprising the following steps: Connect the capillary bundle network on the inner wall of the horizontal well to the surface power supply system and turn on the power to heat the capillary bundle network to the set temperature; After being compressed, the carbon dioxide is injected into a horizontal well through an injection well, while simultaneously being heated using a capillary mesh. Heated carbon dioxide is used to fracture and drive oil out of the shale formations surrounding the horizontal well.

[0008] Compared with existing technologies, the present invention provides an integrated method and system for fracturing and energy recycling of shale oil wells based on simultaneous CO2 heating and injection using capillary bundles, which brings the following significant benefits: (1) Synchronous CO2 heating and injection enhanced fracturing technology based on capillary bundle network. The multi-branch radial customized capillary bundle network of the present invention is made of supercritical CO2 corrosion resistant and high temperature resistant nickel-chromium-molybdenum-niobium alloy material. It can be precisely deployed according to the target layer of the horizontal well to achieve full coverage heating of the target layer. It breaks through the traditional discrete process of "heating before injection". Through the dynamic heat conduction of the capillary network and injected CO2 throughout the process, the injection-heating is synchronized, ensuring that CO2 is maintained at a high temperature of 40~80℃ throughout the target layer. This not only improves the fluidity and volume expansion of CO2 and enhances the fracture propagation and communication ability, but also heats the surrounding rock layer to reduce the viscosity of crude oil, thus solving the dual pain points of low efficiency and difficulty in crude oil displacement of traditional CO2 fracturing.

[0009] The capillary bundle mesh is made of nickel-chromium-molybdenum-niobium alloy and features a multi-branch radial design. It can be customized according to well conditions without damaging the original wellbore structure and fracture network. It is easy to modify, highly adaptable, and can reduce the initial investment and implementation risks of the project, thus expanding the scope of application of the technology.

[0010] (2) Achieve multi-functional coupling of high-temperature CO2-enhanced fracturing and energy self-circulation to form a highly efficient integrated system of fracturing production enhancement, carbon sequestration, and energy recycling. Unlike traditional oil displacement projects that rely on continuous external purchases, this invention achieves the recycling and reuse of CO2 media and the maintenance of high temperature throughout the process. This reduces operating costs and gas source dependence, while also enhancing rock penetration and fracture propagation capabilities with high-temperature CO2. The CO2 permanently sequestered in each cycle is more easily trapped by the rock pore and fracture network, significantly improving the sequestration depth and efficiency. The power generation conversion mode driven by the dual energy of "kinetic energy + thermal energy" through high temperature and high pressure mixed fluid can improve the power generation efficiency compared with the traditional single kinetic energy conversion. The generated electricity forms a self-replenishing energy path of "crude oil lifting - capillary bundle network power supply - gas-liquid separation power supply", which does not require external energy supply and greatly reduces the dependence on external energy. After passing through the turbine power unit, the pressure of the mixed fluid can be reduced to 3~5 MPa, which matches the inlet design pressure of the gas-liquid separation device. There is no need to add pressure reducing or boosting equipment, which simplifies the system structure, reduces equipment investment costs, avoids energy loss caused by additional equipment, and further improves the overall operating efficiency and economy of the system. Attached Figure Description

[0011] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0012] Figure 1 This is a schematic diagram of the original state of the injection well and the connected horizontal well in an embodiment of the present invention; Figure 2 This is a schematic diagram illustrating the linkage between the capillary bundle network arrangement of the target section of the horizontal well and the surface power supply system in an embodiment of the present invention; Figure 3 yes Figure 2 Cross-sectional view at point A; Figure 4 This is a schematic diagram of supercritical CO2 synchronous injection-heating and horizontal well fracturing permeability enhancement in an embodiment of the present invention; Figure 5 This is a schematic diagram of the mixed fluid for carbon dioxide sequestration and production well recovery in an embodiment of the present invention; Figure 6 This is a schematic diagram of the integrated system of mixed fluid energy self-circulation (kinetic energy + thermal energy conversion), gas-liquid separation and CO2 closed-loop circulation in an embodiment of the present invention; Figure 7 yes Figure 6 Detailed structural diagram at point B.

[0013] Among them, 1. mudstone formation, 2. shale formation, 3. injection well, 4. valve, 5. fracture network, 6. capillary bundle network, 7. main pipe, 8. branch capillary bundle, 9. surface power supply system, 10. gaseous CO2, 11. compressor, 12. supercritical CO2, 13. fracture network, 14. production well, 15. isolator, 16. mixed fluid (containing crude oil and high-temperature CO2), 17. oil pumping-power generation co-processing unit, 18. oil pumping unit, 19. turbine power unit, 20. generator, 21. gas-liquid separation unit, 22. oil storage tank. Detailed Implementation

[0014] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0015] To address the technical problems existing in the background art, the present invention provides a CO2 heating and fracturing production enhancement system based on capillary bundle network, comprising a compressor, an injection well and a horizontal well connected in sequence, wherein the horizontal well is in the production decline period; The horizontal well is provided with a capillary bundle network on its sidewall. The capillary bundle network includes several main tubes and several branch capillary bundles. The main tubes are parallel to the axial direction of the horizontal well and are evenly distributed along the circumferential direction of the horizontal well. Several branch capillary bundles are connected between two adjacent main tubes to form a capillary bundle network; Both the main tube and the branch capillary bundles are made of corrosion-resistant and high-temperature resistant nickel-chromium-molybdenum-niobium alloy. The capillary bundle is connected to the ground power supply system, and electricity is supplied to the capillary bundle to heat CO2.

[0016] The capillary bundle network adopts a multi-branch radial structure with a main tube and branch capillary bundles: the main tube is parallel to the axis of the horizontal well and is evenly distributed in the circumference, and the branch capillary bundles connect adjacent main tubes to form a three-dimensional coverage network. It can be precisely arranged according to the horizontal well to achieve full coverage heating of the target layer, with a wide heating range and good uniformity.

[0017] Both the main tube and the branch capillary bundles are made of nickel-chromium-molybdenum-niobium alloy material that is resistant to supercritical CO2 corrosion and high temperature. It has good machinability and can adapt to the high temperature, high pressure and highly corrosive environment downhole, ensuring long-term stable heating and avoiding heating interruption or system damage due to material failure.

[0018] By utilizing a capillary network and dynamic heat conduction throughout the CO2 injection process, injection and heating are synchronized. This ensures that the CO2 remains at a temperature of 40-80°C throughout the target layer, effectively solving the problems of significant temperature drop and viscosity increase during CO2 injection in traditional processes, and maintaining its low viscosity and high flowability characteristics.

[0019] High-temperature CO2 enhances fluidity and volume expansion, efficiently flushing and expanding the existing fracture network to form a more interconnected fracture network, which is more conducive to oil displacement. The heat transferred by the capillary bundle network diffuses to the surrounding rock formations, raising the rock formation temperature, reducing crude oil viscosity, weakening the adsorption between crude oil and rock formations, and simultaneously enhancing the crude oil displacement potential.

[0020] Capillary bundles can be customized according to well conditions without damaging the original wellbore structure and fracture network, making them easy to modify and highly adaptable (such as for modification of shale oil wells in the decline stage).

[0021] Capillary bundles possess excellent flexibility and deformability in their macroscopic structure, allowing them to be integrated into fracturing tubing systems. The mechanical pushing capability of the tubing string as it advances within horizontal well sections enables the entire capillary bundle to be simultaneously delivered to the target location. For ultra-long horizontal well sections, a modular deployment scheme using segmented prefabrication and sequential delivery can be adopted: the capillary bundle is designed as functional segments of standard length, released and delivered segment by segment to the target location during the fracturing tubing string delivery process, thus completing the distributed network layout throughout the entire well section.

[0022] In some embodiments, the diameter of the main pipe is 10-15 mm, and the distance between two adjacent main pipes is 5-8 cm.

[0023] In some embodiments, the diameter of the branch capillary bundle is 1-2 mm, and the distance between two adjacent branch capillary bundles is 5-8 cm.

[0024] The capillary network structure can provide a larger surface area, enabling more efficient dynamic heat transfer between the capillary bundle and CO2, improving the heating efficiency of CO2, and solving the problem of significant temperature drop during CO2 injection in traditional processes.

[0025] The capillary network structure can reduce the amount of special alloys that are resistant to supercritical CO2 corrosion and high temperature, thereby reducing costs while ensuring strength and corrosion resistance.

[0026] In some embodiments, the main tube and branch capillary bundles are made of nickel-chromium-molybdenum-niobium alloy.

[0027] In some embodiments, a capillary bundle network covers a horizontal tube arrangement.

[0028] In some embodiments, a branch is provided on the horizontal well, and the branch connects to two adjacent main pipes.

[0029] In some embodiments, the system further includes a production well, which is vertically arranged and communicates with a horizontal well, and an isolator is provided between the production well and the horizontal well.

[0030] Preferably, the top of the production well is connected to the pumping unit, the outlet of the pumping unit is connected to the turbine generator, and the turbine generator supplies power to the surface power supply system and the pumping unit.

[0031] In a further preferred embodiment, the outlet of the turbine generator is connected to the gas-liquid separator, the liquid outlet of the gas-liquid separator is connected to the oil storage tank, and the gas outlet is connected to the compressor inlet via a pipeline.

[0032] Secondly, the present invention provides a method for CO2 heating and fracturing enhancement based on capillary bundle networks, comprising the following steps: Connect the capillary bundle network on the inner wall of the horizontal well to the surface power supply system and turn on the power to heat the capillary bundle network to the set temperature; After being compressed, the carbon dioxide is injected into a horizontal well through an injection well, while simultaneously being heated using a capillary mesh. Heated carbon dioxide is used to fracture and drive oil out of the shale formations surrounding the horizontal well.

[0033] In some embodiments, the capillary bundle is heated to 40-80°C.

[0034] Preferably, the heated capillary bundle simultaneously heats both carbon dioxide and the shale formation surrounding the horizontal well.

[0035] In some embodiments, carbon dioxide is compressed to form a supercritical fluid state and then injected into a horizontal well through an injection well.

[0036] In some embodiments, the method further includes the step of extracting a mixture of carbon dioxide and oil using a production well. After the extracted mixture generates electricity for a turbine generator, it enters a gas-liquid separator for gas-liquid separation to obtain carbon dioxide gas and oil.

[0037] By connecting the production well and the injection well horizontally, a U-shaped circulation channel is formed. The pressure difference and gravity of the fluid are used to guide the high-temperature and high-pressure mixed fluid (containing crude oil and high-temperature CO2) to flow directionally to the production well.

[0038] An isolator is installed at the end of the production well. During the fracturing and permeability enhancement stage, the isolator is closed to achieve physical isolation between fracturing and production. After fracturing is completed, the isolator is opened to release the mixed fluid into the production well, ensuring the safety and stability of the process switching.

[0039] The extracted mixed fluid, carrying kinetic energy and thermal energy from the capillary bundle network heating, is pumped to the ground by an oil pumping unit to drive a turbine power unit to generate electricity, converting kinetic and thermal energy into electrical energy and realizing energy recovery and utilization.

[0040] Preferably, the separated carbon dioxide gas is compressed and then reinjected into the horizontal well for fracturing and oil displacement.

[0041] Preferably, during the fracturing and oil displacement process, a portion of the carbon dioxide is permanently sealed.

[0042] The present invention will be further described below with reference to the embodiments.

[0043] A CO2 heating and fracturing production enhancement system based on capillary bundle network includes a compressor 11, an injection well 3, a horizontal well and a production well 14 connected in sequence, wherein the horizontal well is in the production decline period; The horizontal well is provided with a capillary bundle network on its sidewall. The capillary bundle network includes several main tubes 7 and several branch capillary bundles 8. The main tubes 7 are parallel to the axial direction of the horizontal well and are evenly distributed along the circumference of the horizontal well. Branches are provided on the horizontal well, and the branches are connected to the fracture network 13. Several branch capillary bundles 8 are connected between two adjacent main tubes 7 to form a capillary bundle network; The diameter of the main tube 7 is 10-15mm, and the distance between two adjacent main tubes 7 is 5-8cm; the diameter of the branch capillary bundle 8 is 1-2mm, and the distance between two adjacent branch capillary bundles 8 is 5-8cm. Both the main tube 7 and the branch capillary bundle 8 are made of corrosion-resistant, high-temperature resistant nickel-chromium-molybdenum-niobium alloy; The capillary bundle is connected to the ground power supply system 9, which powers the capillary bundle to heat CO2.

[0044] The production well 14 is vertically positioned and connected to the horizontal well, with an isolator 15 installed between the production well 14 and the horizontal well. The top of the production well 14 is connected to the pumping unit 18, and the outlet of the pumping unit 18 is connected to a turbine generator. The turbine generator includes a turbine power unit 19 and a generator 20, which supplies power to the surface power system and the pumping unit. The outlet of the turbine generator is connected to a gas-liquid separator 21, the liquid outlet of which is connected to an oil storage tank 22, and the gas outlet is connected to the inlet of the compressor 11 via a pipeline.

[0045] Capillary bundles possess excellent flexibility and deformability, allowing them to be integrated into fracturing tubing systems. The mechanical pushing capability of the tubing as it advances within horizontal well sections enables the entire capillary bundle to be simultaneously delivered to the target location. For ultra-long horizontal well sections, a modular deployment scheme using segmented prefabrication and sequential delivery can be adopted: the capillary bundle is designed as functional segments of standard length, released and delivered segment by segment to the target location during the fracturing tubing push process, thus completing the distributed network layout throughout the entire well section.

[0046] The construction method of the CO2 heating and fracturing enhancement system based on capillary bundle network is as follows: like Figure 1 As shown, a horizontal well 3, located in the target shale oil reservoir 2 and already in the production decline phase, was selected as the implementation well. Well cleaning and flushing operations were performed to ensure unobstructed wellbore flow. A valve was installed at the wellhead of injection well 4 for later control of gas injection. like Figure 2 As shown, for the geological parameters of the target formation in the horizontal section of injection well 3, a distributed capillary bundle network 6 made of a special alloy material resistant to supercritical CO2 corrosion and high temperature (≥120℃) was designed and installed. This network adopts a multi-branch radial structure. The main pipes 7 (diameter 10~15 mm, spacing 5~8 cm) are arranged along the horizontal well axis, and the branch capillary bundles 8 (diameter 1~2 mm, spacing 5~8 cm) are distributed in a ring around the well wall, with their ends close to the end of the horizontal well. Figure 3 As shown, this achieves full-coverage heating of the target layer. The capillary bundle network 6 is linked with the ground power supply system 9 to adapt to the needs of different fracturing stages.

[0047] like Figure 4 As shown, after the capillary bundle network 6 is installed and debugged, the ground power supply system 9 is started to preheat the capillary bundle network 6. After the network wall temperature stabilizes to the set threshold (40~80℃), gaseous CO210 is continuously fed into the electrically driven compressor 11 and compressed to a supercritical state. Supercritical CO212 is then input into the injection well 3. The CO2 fully contacts the capillary bundle network 6 in the horizontal well section, achieving dynamic heating throughout the process through heat conduction from the pipe wall. Unlike the traditional discrete process of "heating before injection", this innovative design achieves injection and... Synchronized heating ensures that CO2 maintains a high temperature throughout the target layer. Heating CO2 enhances its fluidity and volume expansion, efficiently flushing and expanding the existing fracture network to form a more interconnected artificial fracture network 13. Simultaneously, the heat transferred by the capillary bundle network 6 diffuses to the surrounding rock formations through thermal conduction, raising the rock formation temperature and directly reducing the viscosity of the formation crude oil. This weakens the adsorption between crude oil and the rock formation, simultaneously improving fracturing efficiency and crude oil displacement potential, laying a crucial foundation for subsequent efficient crude oil displacement.

[0048] like Figure 5 As shown, based on the geological survey results, a vertical shaft is drilled into the rock strata as a production well 14, which is connected to the horizontal section of the horizontal well away from the injection end, forming a U-shaped circulation channel, which is conducive to the directional flow of the mixed fluid and its subsequent recycling. An isolator 15 is installed at the end of the production well 14. During the fracturing and permeability enhancement stage, the isolator 15 is closed to achieve physical isolation between the fracturing process and the production process. After the fracturing is completed, valve 4 is closed, isolator 15 is opened, and the high-speed high-temperature mixed fluid 16 is recycled.

[0049] like Figure 6 and Figure 7 As shown, the high-temperature, high-pressure mixed fluid 16 (temperature 40~80 ℃, pressure 10~30 MPa) recovered from the production well is output by the pumping unit 18 and directly enters the turbine power unit 19. The mixed fluid 16 carries both the high kinetic energy generated by the high-pressure backflow and the significant thermal energy imparted by the capillary bundle network heating. The dual energy works together to impact the power blades in the turbine power unit 19, driving the main shaft to rotate at high speed, efficiently converting the fluid potential energy and thermal energy into mechanical energy simultaneously. Since the turbine rotor of the turbine power unit 19 and the rotor of the generator 20 are coaxially connected, the rotation of the main shaft directly drives the generator 20 to cut magnetic field lines, realizing the efficient conversion of mechanical energy into electrical energy. Compared with the mode of converting only kinetic energy of normal temperature fluid, this helps to improve power generation efficiency. The generated electrical energy is distributed through the energy regulation module: it is preferentially supplied directly to the pumping unit 18 to ensure the continuous operation of crude oil lifting, part of the electrical energy is allocated to the ground power supply system 9 to support the CO2 heating operation in the subsequent cycle, and the remaining electrical energy is supplied to the gas-liquid separator 21, significantly improving the overall energy utilization rate.

[0050] Meanwhile, after passing through the turbine power unit 19, the pressure of the fluid is steadily reduced to 3~5 MPa, avoiding the impact of sudden pressure changes on the separation efficiency of the gas-liquid separator 21. The fluid then smoothly enters the separator 21 for efficient separation. The separated crude oil is transported to the shale oil storage tank 22 for storage and external transport, while the remaining gaseous CO2 is transported back to the electrically driven compressor 11 through the recovery pipeline to enter the next closed-loop cycle operation.

[0051] In each cycle, a portion of CO2 is permanently sealed within the micro-nano pore and fracture network of the shale reservoir, achieving multiple objectives such as CO2 recycling and storage, efficient shale oil production, and autonomous energy recycling.

[0052] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A CO2 heating and fracturing production enhancement system based on capillary bundle network, characterized in that: It includes a compressor, an injection well, and a horizontal well connected in sequence, wherein the horizontal well is in a production decline phase; The horizontal well is provided with a capillary bundle network on its sidewall. The capillary bundle network includes several main tubes and several branch capillary bundles. The main tubes are parallel to the axial direction of the horizontal well and are evenly distributed along the circumferential direction of the horizontal well. Several branch capillary bundles are connected between two adjacent main tubes to form a capillary bundle network; Both the main tube and the branch capillary bundles are made of corrosion-resistant, high-temperature-resistant nickel-chromium-molybdenum-niobium alloy material; The capillary bundle is connected to the ground power supply system, and electricity is supplied to the capillary bundle to heat CO2.

2. The CO2 heating and fracturing production enhancement system based on capillary bundle network according to claim 1, characterized in that: The diameter of the main pipe is 10-15mm, and the distance between two adjacent main pipes is 5-8cm. Alternatively, the diameter of the branched capillary bundles is 1-2 mm, and the distance between two adjacent branched capillary bundles is 5-8 cm.

3. The CO2 heating and fracturing production enhancement system based on capillary bundle network according to claim 2, characterized in that: The main tube and branch capillary bundles are made of nickel-chromium-molybdenum-niobium alloy.

4. The CO2 heating and fracturing production enhancement system based on capillary bundle network according to claim 1, characterized in that: The capillary bundle network covers the horizontal tube setting.

5. The CO2 heating and fracturing production enhancement system based on capillary bundle network according to claim 1, characterized in that: The system also includes a production well, which is vertically arranged and connected to a horizontal well, and an isolator is installed between the production well and the horizontal well; Preferably, the top of the production well is connected to the pumping unit, the outlet of the pumping unit is connected to the turbine generator, and the turbine generator supplies power to the surface power supply system and the pumping unit. Preferably, the outlet of the turbine generator is connected to the gas-liquid separator, the liquid outlet of the gas-liquid separator is connected to the oil storage tank, and the gas outlet is connected to the compressor inlet through a pipeline.

6. A method for CO2 heating and fracturing production enhancement based on capillary bundle network, characterized in that: The CO2 heating and fracturing production enhancement system based on capillary bundles as described in any one of claims 1-5 is used, comprising the following steps: Connect the capillary bundle network on the inner wall of the horizontal well to the surface power supply system and turn on the power to heat the capillary bundle network to the set temperature; After being compressed, the carbon dioxide is injected into a horizontal well through an injection well, while simultaneously being heated using a capillary mesh. Heated carbon dioxide is used to fracture and drive oil out of the shale formations surrounding the horizontal well.

7. The CO2 heating and fracturing production enhancement method based on capillary bundle network according to claim 6, characterized in that: Heat the capillary bundle mesh to 40-80℃; Preferably, the heated capillary bundle simultaneously heats both carbon dioxide and the shale formation surrounding the horizontal well.

8. The CO2 heating and fracturing production enhancement method based on capillary bundle network according to claim 6, characterized in that: Carbon dioxide is compressed to form a supercritical fluid state, and then injected into a horizontal well through an injection well.

9. The CO2 heating and fracturing production enhancement method based on capillary bundle network according to claim 6, characterized in that: It also includes the step of extracting a mixture of carbon dioxide and oil using a production well. After the extracted mixture generates electricity for a turbine generator, it enters a gas-liquid separator for gas-liquid separation, separating carbon dioxide gas and oil.

10. The CO2 heating and fracturing production enhancement method based on capillary bundle network according to claim 6, characterized in that: The separated carbon dioxide gas is compressed and then reinjected into the horizontal well for fracturing and oil displacement. Preferably, during the fracturing and oil displacement process, a portion of the carbon dioxide is permanently sealed.

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