CO2 geological sequestration coordinated shale oil and geothermal energy green development system and method

Abstract

The invention discloses a CO2 geological storage coordinated shale oil and geothermal energy green development system and method. The system comprises a geothermal power station located on the ground, a ground cable, a CO2 injection device, a CO2 conveying pipeline, a CO2 / shale oil separation device, a shale oil conveying pipeline and a shale oil storage tank. Wherein the geothermal power station is connected with the CO2 injection device through a ground cable, the CO2 injection device is connected with the CO2 / shale oil separation device through a CO2 conveying pipeline, and the CO2 / shale oil separation device is connected with the shale oil storage tank through a shale oil conveying pipeline; through multiple utilization and innovative closed circulation of CO2, an efficient energy development system is built, the recovery ratio of shale oil is increased, geological storage of CO2 and geothermal energy development are achieved, energy consumption and carbon emission are reduced, and therefore the environmental pollution risk is effectively reduced, and unification of economic benefits and environmental benefits is achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of energy development and utilization, and specifically relates to a system and method for green development of CO2 geological storage coordinated with shale oil and geothermal energy. Background Art

[0002] As an unconventional oil and gas resource, shale oil has achieved remarkable development in recent years around the world, especially in the United States. The successful development of shale oil has promoted changes in the global oil and gas supply and demand pattern. At present, CO2 flooding technology has been widely used in shale oil extraction. CO2 is injected into the formation to dissolve the light components in the crude oil, reduce the viscosity of the crude oil, and thus increase the recovery rate of the crude oil. However, traditional CO2 flooding technology has many shortcomings. After the flooding process is completed, some of the unrecovered CO2 may leak into the atmosphere through rock cracks or other channels, resulting in potential environmental pollution and greenhouse gas emission risks. The CO2 storage effect of this technology is poor, lacks effective recycling and storage design, and cannot achieve long-term safe storage of CO2.

[0003] Geothermal resources, especially hot dry rock resources, have attracted much attention as a clean energy with huge reserves. Hot dry rock resources have high temperatures and wide distribution, and have great development potential. In recent years, researchers have tried to use a variety of working media for geothermal energy extraction, including water, N2 and CO2. Among them, CO2 is considered to be a promising working medium for the development of hot dry rock geothermal resources due to its unique physical properties, such as high heat transfer efficiency and low viscosity. Despite this, there are still major limitations in the economic benefits of CO2 geothermal development. The main reason is that CO2 is only used as a heat transfer medium and fails to bring additional sources of economic benefits. Especially when the initial investment is huge and the long-term return is slow, this type of technology is difficult to achieve economic feasibility.

[0004] In contrast, the present invention proposes an integrated system that comprehensively utilizes CO2 to drive green shale oil mining, geological storage, and geothermal energy development. During the CO2 flooding process, the system not only achieves efficient recovery of shale oil, but also permanently seals the unproduced CO2 in shale oil reservoirs or geothermal reservoirs by designing a storage process, thereby avoiding CO2 leakage into the atmosphere and eliminating the risk of environmental pollution. At the same time, the present invention increases the additional economic benefits of the system by combining CO2 flooding with geothermal energy development. After flooding, CO2 is sealed in the geothermal reservoir, and power is generated by exploiting geothermal energy, achieving maximum resource utilization and a closed cycle of the system. This innovative design not only improves the overall economic benefits, but also significantly reduces environmental risks and solves many deficiencies in the prior art. Summary of the invention

[0005] In view of the above-mentioned deficiencies in the prior art, the CO2 geological storage coordinated shale oil and geothermal energy green development system and method provided by the present invention, through innovative multiple utilization of CO2, constructs a closed circulation system, organically combines CO2 oil recovery with geothermal development, and solves the problems of CO2 leakage, environmental risks and low economic benefits in the prior art.

[0006] In order to achieve the above-mentioned invention object, the technical solution adopted by the present invention is: a CO2 geological storage coordinated shale oil and geothermal energy green development system, including a geothermal power station located on the ground, a ground cable, a first CO2 transmission pipeline, a CO2 injection device, a second CO2 transmission pipeline, a CO2 / shale oil separation device, a shale oil transmission pipeline and a shale oil storage tank; The geothermal power station is connected to the CO2 injection device through a ground cable and a first CO2 delivery pipeline, the CO2 injection device is connected to the CO2 / shale oil separation device through a second CO2 delivery pipeline, and the CO2 / shale oil separation device is connected to the shale oil storage tank through a shale oil delivery pipeline. Below the ground are the upper covering layer, the shale oil reservoir, and the geothermal reservoir in order; the geothermal reservoir fracturing transformation area is located in the geothermal reservoir, the shale oil reservoir fracturing transformation area is located in the shale oil reservoir, the CO2 injection device is connected to the input end of the CO2 injection well, the output end of the CO2 injection well is located in the shale oil reservoir fracturing transformation area and the geothermal reservoir fracturing transformation area, the input end of the geothermal production well is located in the geothermal reservoir fracturing transformation area, the output end of the geothermal production well is connected to the geothermal power station, the input end of the shale oil production well is located in the shale oil reservoir fracturing transformation area, and the output end of the shale oil production well is connected to the CO2 / shale oil separation device; The CO2 injection well is used to inject CO2 into the geothermal reservoir fracturing and transformation area and the shale oil reservoir fracturing and transformation area, the shale oil production well is used to collect the mixture of CO2 and shale oil from the shale oil reservoir, the geothermal production well is used to collect the high-temperature CO2 from the geothermal reservoir, the geothermal power station is used to generate electricity using the collected high-temperature CO2, the CO2 / shale oil separation device is used to separate CO2 from shale oil, the separated CO2 is input into the CO2 injection well through the second CO2 transmission pipeline, and the separated shale oil is input into the shale oil storage tank through the shale oil transmission pipeline.

[0007] Furthermore: the CO2 injection device is also connected to the CO2 capture device and the CO2 emission plant in sequence through a second CO2 transmission pipeline.

[0008] A method for green development of CO2 geological storage in coordination with shale oil and geothermal energy, the method comprising the following steps: S1. Select shale oil reservoirs with rich shale oil reserves and geothermal reservoirs with rich geothermal resources as target areas; S2. Inject high-pressure CO2 into the shale oil reservoir and the geothermal reservoir through the CO2 injection well to perform fracturing operations, and establish a shale oil reservoir fracturing transformation area and a geothermal reservoir fracturing transformation area; S3. After fracturing is completed, high-pressure CO2 is continuously injected through the CO2 injection well to drive oil and recover heat, a mixture of CO2 and shale oil is collected through the shale oil production well, and high-temperature CO2 is collected through the geothermal production well; S4, using high-temperature CO2 to generate geothermal power through a geothermal power station to provide electricity for the CO2 injection device, and transporting the low-temperature CO2 after power generation to the CO2 injection device through a first CO2 transport pipeline, and continuing to inject the CO2 into the formation through the CO2 injection well for circulation; S5. Based on the mixture of CO2 and shale oil, CO2 and shale oil are separated by a CO2 / shale oil separation device, the separated CO2 is input to a CO2 injection well through a second CO2 transmission pipeline, and the separated shale oil is input to a shale oil storage tank through a shale oil transmission pipeline; S6. CO2 is captured from the CO2 emission plant through the CO2 capture device and transported to the CO2 injection well. The CO2 is circulated and injected into the geothermal reservoir fracturing transformation area and the shale oil reservoir fracturing transformation area through the CO2 injection well to form a complete closed cycle of CO2 storage and energy extraction.

[0009] The beneficial effects of the present invention are as follows: the present invention provides a system and method for the green development of CO2 geological storage in coordination with shale oil and geothermal energy, and forms a complete closed cycle of CO2 storage and energy exploitation by coupling CO2 fracturing-CO2 displacement exploitation of shale oil-CO2 circulation exploitation of heat storage system, thereby improving energy exploitation efficiency, reducing energy consumption and carbon emissions, and thus effectively reducing the risk of environmental pollution, which is different from the traditional single CO2 oil recovery technology.

[0010] The present invention combines the development of renewable energy (geothermal energy) with fossil energy (shale oil), and utilizes additional benefits such as shale oil development and carbon sequestration subsidies to overcome the poor economic efficiency of single CO2 geothermal extraction technology.

[0011] The present invention creates an efficient energy development system through multiple utilizations of CO2 and innovative closed cycles, which not only improves the recovery rate of shale oil, but also achieves the unity of economic and environmental benefits through geothermal power generation and CO2 utilization and storage.

[0012] The present invention adopts an innovative design of the CO2 injection well 7. The CO2 injection well 7 is a multi-branch well, and its branches are respectively located in the shale oil reservoir and the geothermal reservoir. This design allows CO2 to be injected into different reservoirs at the same time, achieving efficient displacement of shale oil and efficient collection of geothermal energy, optimizing the wellbore layout and improving the efficiency of the overall system.

[0013] The present invention also has extremely high flexibility. If the shale oil reservoirs are exhausted in the later stage, the abandoned shale oil wells can be directly converted into geothermal wells for development and utilization, saving the cost of drilling and infrastructure transformation and maximizing the use of existing infrastructure and resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a schematic diagram of the CO2 geological storage coordinated with shale oil and geothermal energy green development system of the present invention.

[0015] Figure 2 This is a flow chart of the green development method of CO2 geological storage in coordination with shale oil and geothermal energy of the present invention.

[0016] Figure 3 This is a process flow chart of the CO2 geological storage coordinated with shale oil and geothermal energy green development system of the present invention.

[0017] Among them: 1. Overburden; 2. Shale oil reservoir; 3. Geothermal reservoir; 4. Geothermal reservoir fracturing and transformation area; 5. Shale oil reservoir fracturing and transformation area; 6. Geothermal production well; 7. CO2 injection well; 8. Shale oil production well; 9. Geothermal power station; 10. Ground cable; 11. First CO2 pipeline; 12. CO2 injection device; 13. Second CO2 pipeline; 14. CO2 / shale oil separation device; 15. CO2 capture device; 16. CO2 emission plant; 17. Shale oil pipeline; 18. Shale oil storage tank. DETAILED DESCRIPTION

[0018] The specific implementation modes of the present invention are described below so that those skilled in the art can understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific implementation modes. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious, and all inventions and creations utilizing the concept of the present invention are protected.

[0019] like Figure 1 As shown, in one embodiment of the present invention, a CO2 geological storage coordinated shale oil and geothermal energy green development system includes a geothermal power plant 9 located on the ground, a ground cable 10, a first CO2 transmission pipeline 11, a CO2 injection device 12, a second CO2 transmission pipeline 13, a CO2 / shale oil separation device 14, a shale oil transmission pipeline 17 and a shale oil storage tank 18; The geothermal power station 9 is connected to the CO2 injection device 12 through the ground cable 10 and the first CO2 delivery pipeline 11 respectively, the CO2 injection device 12 is connected to the CO2 / shale oil separation device 14 through the second CO2 delivery pipeline 13, and the CO2 / shale oil separation device 14 is connected to the shale oil storage tank 18 through the shale oil delivery pipeline 17; Below the ground are the upper covering layer 1, the shale oil reservoir 2, and the geothermal reservoir 3 in order; the geothermal reservoir fracturing transformation area 4 is located in the geothermal reservoir 3; the shale oil reservoir fracturing transformation area 5 is located in the shale oil reservoir 2; the CO2 injection device 12 is connected to the input end of the CO2 injection well 7; the output end of the CO2 injection well 7 is located in the shale oil reservoir fracturing transformation area 5 and the geothermal reservoir fracturing transformation area 4; the input end of the geothermal production well 6 is located in the geothermal reservoir fracturing transformation area 4; the output end of the geothermal production well 6 is connected to the geothermal power station 9; the input end of the shale oil production well 8 is located in the shale oil reservoir fracturing transformation area 5; and the output end of the shale oil production well 8 is connected to the CO2 / shale oil separation device 14; The shale oil reservoir fracturing transformation area 5 and the geothermal reservoir fracturing transformation area 4 are both fractured by high-pressure CO2 injection to improve the permeability of the reservoir. The CO2 injection well 7 is used to inject CO2 into the geothermal reservoir fracturing transformation area 4 and the shale oil reservoir fracturing transformation area 5 to achieve shale oil displacement and geothermal energy development. The shale oil production well 8 is used to collect the mixture of CO2 and shale oil from the shale oil reservoir 2. The geothermal production well 6 is used to collect high-temperature CO2 from the geothermal reservoir 3. The geothermal power station 9 is used to generate electricity using the collected high-temperature CO2. The CO2 / shale oil separation device 14 is used to separate CO2 from shale oil. The separated CO2 is input into the CO2 injection well 7 through the second CO2 transmission pipeline 13 for the next oil displacement and heat recovery, forming a closed cycle to ensure the effective utilization and storage of CO2. The separated shale oil is input into the shale oil storage tank 18 through the shale oil transmission pipeline 17.

[0020] The CO 2 injection device 12 is also connected to a CO 2 capture device 15 and a CO 2 emission plant 16 in sequence through a second CO 2 transmission pipeline 13 .

[0021] In this embodiment, the separated shale oil is processed and then sent to the shale oil storage tank 18 for storage or further processing through the shale oil pipeline 17. The geothermal power station 9 generates electricity using the high-temperature CO2 collected from the geothermal production well 6, and transmits the electricity to the CO2 injection device 12 or the power grid through the ground cable 10.

[0022] like Figure 2~3 As shown, the CO2 geological storage and shale oil and geothermal energy green development method comprises the following steps: S1, selecting shale oil reservoir 2 with rich shale oil reserves and geothermal reservoir 3 with rich geothermal resource reserves as the target area; In this embodiment, an area rich in shale oil and geothermal resources is selected as the target area. Through geological survey, the reserves and location of the target strata are determined to ensure that the development conditions of the shale oil layer and the geothermal reservoir 3 meet the requirements of the present invention.

[0023] S2, injecting high-pressure CO2 into the shale oil reservoir 2 and the geothermal reservoir 3 through the CO2 injection well 7, performing fracturing operations, and establishing a shale oil reservoir fracturing transformation area 5 and a geothermal reservoir fracturing transformation area 4; In this embodiment, the CO2 injection well 7 is a multi-branch well, and its branches are respectively located in the shale oil reservoir 2 and the geothermal reservoir 3, so that CO2 can be injected into different reservoirs at the same time, realizing efficient displacement of shale oil and efficient collection of geothermal energy; the production wells are respectively arranged in the shale oil reservoir 2 and the geothermal reservoir 3, the production wells of the shale oil layer are used for shale oil displacement, and the production wells of the geothermal reservoir 3 are used for geothermal energy extraction. The spacing and depth of the wellheads are designed according to the specific geological conditions to ensure the efficient operation of the CO2 displacement and heat recovery process. For exhausted shale oil wells, they can be transformed into geothermal wells, saving drilling costs and making full use of existing infrastructure. The CO2 injected for the first time is captured by CO2 trading or CO2 emission plants 16. CO2 is used as a working medium to form a fracture network through fracturing. The fractures enhance the permeability of the reservoir and provide an effective flow channel for CO2 oil displacement and heat recovery.

[0024] S3, after the fracturing is completed, high-pressure CO2 is continuously injected through the CO2 injection well 7 to drive oil and recover heat, a mixture of CO2 and shale oil is collected through the shale oil production well 8, and high-temperature CO2 is collected through the geothermal production well 6; In this embodiment, after the fracturing is completed, CO2 is continuously injected into the shale oil reservoir to drive oil. CO2 dissolves the light components in the shale oil, reduces the viscosity of the oil, and improves its fluidity. In this process, part of the CO2 is mixed with the crude oil, and the other part of the CO2 is sealed in the shale layer, reducing CO2 emissions.

[0025] S4, using the high-temperature CO2 to generate geothermal power through the geothermal power station 9, providing electricity for the CO2 injection device 12, and transporting the low-temperature CO2 after power generation to the CO2 injection device 12 through the first CO2 transport pipeline 11, and continuing to inject into the formation through the CO2 injection well 7 for circulation; In this embodiment, the organic Rankine cycle (ORC) is used to convert the thermal energy of high-temperature CO2 into the kinetic energy of the turbine to drive the generator to generate electricity. The electricity generated can provide continuous power for CO2 injection, thus forming a closed energy utilization cycle. After CO2 generates electricity, its temperature drops, but it still has enough waste heat, which can be used for domestic heating, oil pipeline heating, pipeline cleaning, etc., which improves the comprehensive utilization efficiency of CO2 and maximizes the energy value of CO2.

[0026] S5, based on the mixture of CO2 and shale oil, CO2 and shale oil are separated by a CO2 / shale oil separation device 14, the separated CO2 is input to a CO2 injection well 7 through a second CO2 transmission pipeline 13, and the separated shale oil is input to a shale oil storage tank 18 through a shale oil transmission pipeline 17; S6. CO2 is captured from the CO2 emission plant 16 through the CO2 capture device 15 and transported to the CO2 injection well 7. The CO2 is circulated and injected into the geothermal reservoir fracturing transformation area 4 and the shale oil reservoir fracturing transformation area 5 through the CO2 injection well 7 to form a complete closed cycle of CO2 storage and energy extraction.

[0027] In this embodiment, the separated and captured CO2 is injected into the geothermal reservoir 3, and CO2 is used as a working fluid to extract geothermal energy from the heat storage. In this process, part of the CO2 is sealed in the geothermal reservoir 3, and the other part of the high-temperature CO2 returns to the ground through the production well to provide energy for subsequent power generation and heating.

[0028] The beneficial effects of the present invention are as follows: the present invention provides a system and method for the green development of CO2 geological storage in coordination with shale oil and geothermal energy, and forms a complete closed cycle of CO2 storage and energy exploitation by coupling CO2 fracturing-CO2 displacement exploitation of shale oil-CO2 circulation exploitation of heat storage system, thereby improving energy exploitation efficiency, reducing energy consumption and carbon emissions, and thus effectively reducing the risk of environmental pollution, which is different from the traditional single CO2 oil recovery technology.

[0029] The present invention combines the development of renewable energy (geothermal energy) with fossil energy (shale oil), and utilizes additional benefits such as shale oil development and carbon sequestration subsidies to overcome the poor economic efficiency of single CO2 geothermal extraction technology.

[0030] The present invention creates an efficient energy development system through multiple utilizations of CO2 and innovative closed cycles, which not only improves the recovery rate of shale oil, but also achieves the unity of economic and environmental benefits through geothermal power generation and CO2 utilization and storage.

[0031] The present invention adopts an innovative design of the CO2 injection well 7. The CO2 injection well 7 is a multi-branch well, and its branches are respectively located in the shale oil reservoir 2 and the geothermal reservoir 3. This design allows CO2 to be injected into different reservoirs at the same time, achieving efficient displacement of shale oil and efficient collection of geothermal energy, optimizing the wellbore layout and improving the efficiency of the overall system.

[0032] The present invention also has extremely high flexibility. If the shale oil reservoirs are exhausted in the later stage, the abandoned shale oil wells can be directly converted into geothermal wells for development and utilization, saving the cost of drilling and infrastructure transformation and maximizing the use of existing infrastructure and resources.

[0033] In the description of the present invention, it is necessary to understand that the orientation or positional relationship indicated by the terms "center", "thickness", "upper", "lower", "horizontal", "top", "bottom", "inner", "outer", "radial", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", and "third" are used only for descriptive purposes, and cannot be understood as indicating or implying the relative importance or the number of implicitly specified technical features. Therefore, the features defined by "first", "second", and "third" may explicitly or implicitly include one or more of the features.

Claims

1. CO2 geological storage and shale oil and geothermal energy green development system, characterized by: It comprises a geothermal power station (9) located on the ground, a ground cable (10), a first CO2 transmission pipeline (11), a CO2 injection device (12), a second CO2 transmission pipeline (13), a CO2 / shale oil separation device (14), a shale oil transmission pipeline (17) and a shale oil storage tank (18); The geothermal power station (9) is connected to a CO2 injection device (12) via a ground cable (10) and a first CO2 transmission pipeline (11), respectively; the CO2 injection device (12) is connected to a CO2 / shale oil separation device (14) via a second CO2 transmission pipeline (13); and the CO2 / shale oil separation device (14) is connected to a shale oil storage tank (18) via a shale oil transmission pipeline (17); Below the ground are the upper covering layer (1), the shale oil reservoir (2), and the geothermal reservoir (3), the geothermal reservoir fracturing transformation area (4) is located in the geothermal reservoir (3), the shale oil reservoir fracturing transformation area (5) is located in the shale oil reservoir (2), the CO2 injection device (12) is connected to the input end of the CO2 injection well (7), the output end of the CO2 injection well (7) is located in the shale oil reservoir fracturing transformation area (5) and the geothermal reservoir fracturing transformation area (4), the input end of the geothermal production well (6) is located in the geothermal reservoir fracturing transformation area (4), the output end of the geothermal production well (6) is connected to the geothermal power station (9), the input end of the shale oil production well (8) is located in the shale oil reservoir fracturing transformation area (5), and the output end of the shale oil production well (8) is connected to the CO2 / shale oil separation device (14); The CO2 injection well (7) is used to inject CO2 into the geothermal reservoir fracturing transformation area (4) and the shale oil reservoir fracturing transformation area (5); the shale oil production well (8) is used to collect the mixture of CO2 and shale oil from the shale oil reservoir (2); the geothermal production well (6) is used to collect high-temperature CO2 from the geothermal reservoir (3); the geothermal power station (9) is used to generate electricity using the collected high-temperature CO2; the CO2 / shale oil separation device (14) is used to separate CO2 from shale oil; the separated CO2 is input into the CO2 injection well (7) through the second CO2 transmission pipeline (13); and the separated shale oil is input into the shale oil storage tank (18) through the shale oil transmission pipeline (17).

2. The CO2 geological storage coordinated shale oil and geothermal energy green development system according to claim 1 is characterized in that: The CO2 injection device (12) is also connected to the CO2 capture device (15) and the CO2 emission plant (16) in sequence through a second CO2 transmission pipeline (13).

3. A method for the green development of CO2 geological storage in cooperation with shale oil and geothermal energy, applied to a system for the green development of CO2 geological storage in cooperation with shale oil and geothermal energy as claimed in any one of claims 1 to 2, characterized in that: The method comprises the following steps: S1. Selecting a shale oil reservoir (2) with rich shale oil reserves and a geothermal reservoir (3) with rich geothermal resource reserves as the target area; S2, injecting high-pressure CO2 into the shale oil reservoir (2) and the geothermal reservoir (3) through the CO2 injection well (7), performing fracturing operations, and establishing a shale oil reservoir fracturing transformation area (5) and a geothermal reservoir fracturing transformation area (4); S3, after the fracturing is completed, high-pressure CO2 is continuously injected through the CO2 injection well (7) to drive oil and recover heat, a mixture of CO2 and shale oil is collected through the shale oil production well (8), and high-temperature CO2 is collected through the geothermal production well (6); S4, using the high-temperature CO2 to generate geothermal power through the geothermal power station (9), providing electricity for the CO2 injection device (12), transporting the low-temperature CO2 after power generation to the CO2 injection device (12) through the first CO2 transport pipeline (11), and continuing to inject the CO2 into the formation through the CO2 injection well (7) for circulation; S5. Based on the mixture of CO2 and shale oil, CO2 and shale oil are separated by a CO2 / shale oil separation device (14), the separated CO2 is input into a CO2 injection well (7) through a second CO2 transmission pipeline (13), and the separated shale oil is input into a shale oil storage tank (18) through a shale oil transmission pipeline (17); S6. CO2 is captured from the CO2 emission plant (16) by a CO2 capture device (15) and transported to a CO2 injection well (7). The CO2 is then cyclically injected into a geothermal reservoir fracturing transformation area (4) and a shale oil reservoir fracturing transformation area (5) through the CO2 injection well (7) to form a complete closed cycle of CO2 storage and energy extraction.

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