CO2 Geological Storage Collaborative Shale Oil and Geothermal Energy Green Development System and Method

Abstract

The present invention discloses a CO2 geological sequestration collaborative shale oil and geothermal energy green development system and method. The system includes a geothermal power station located on the ground, a ground cable, a CO2 injection device, a CO2 transportation pipeline, a CO2 / shale oil separation device, a shale oil transportation pipeline, and a shale oil storage tank. Among them, the geothermal power station is connected to the CO2 injection device through the ground cable, the CO2 injection device is connected to the CO2 / shale oil separation device through the CO2 transportation pipeline, and the CO2 / shale oil separation device is connected to the shale oil storage tank through the shale oil transportation pipeline. The present invention creates an efficient energy development system through the multiple utilization and innovative closed cycle of CO2, not only improving the recovery rate of shale oil, but also realizing the geological sequestration of CO2 and the development of geothermal energy, reducing energy consumption and carbon emissions, thereby effectively reducing the risk of environmental pollution and achieving the unity of economic benefits and environmental benefits.

Description

Technical Field

[0001] The present invention belongs to the technical field of energy development and utilization, and particularly relates to a CO2 geological sequestration collaborative shale oil and geothermal energy green development system and method. Background Art

[0002] As an unconventional oil and gas resource, shale oil has achieved remarkable development globally in recent years. Especially in the United States, the successful development of shale oil has promoted the change of the global oil and gas supply and demand pattern. Currently, the CO2 flooding technology has been widely applied in shale oil exploitation. By injecting CO2 into the formation, the light components in the crude oil are dissolved, and the viscosity of the crude oil is reduced, thereby improving the oil recovery rate. However, the traditional CO2 flooding technology has many deficiencies. After the oil displacement process ends, some un-recovered CO2 may leak into the atmosphere through rock fractures or other channels, resulting in potential environmental pollution and greenhouse gas emission risks. The CO2 sequestration effect of this technology is poor, lacking effective recycling and sequestration designs, and unable to achieve the long-term safe sequestration of CO2.

[0003] Geothermal resources, especially hot dry rock resources, as a huge reserve of clean energy, have attracted much attention. Hot dry rock resources have high temperatures and wide distributions, with great development potential. In recent years, researchers have tried to use various working media for geothermal energy exploitation, including water, N2, and CO2, etc. Among them, CO2 is considered a promising working medium for developing hot dry rock geothermal resources due to its unique physical properties, such as higher heat transfer efficiency and lower viscosity. Nevertheless, there are still significant limitations in the economic benefits of CO2 geothermal development. The main reason is that CO2 is only used as a heat transfer medium and does not bring additional economic revenue sources. Especially in the case of huge initial investments and slow long-term returns, such technologies are difficult to achieve economic feasibility.

[0004] In contrast, the present invention proposes an integrated system for comprehensively utilizing CO2 to drive the green exploitation of shale oil, geological sequestration, and geothermal energy development. During the CO2 flooding process, this system not only realizes the efficient recovery of shale oil but also permanently sequesters the un-recovered CO2 in the shale oil reservoir or geothermal reservoir by designing the sequestration process, avoiding the leakage of CO2 into the atmosphere and eliminating the risk of environmental pollution. At the same time, the present invention combines CO2 flooding with geothermal energy development, increasing the additional economic benefits of the system. After CO2 is used for oil displacement, it is sequestered in the geothermal reservoir and used for power generation by exploiting geothermal energy, realizing the maximum utilization of resources and the closed-loop cycle of the system. This innovative design not only improves the overall economic benefits but also significantly reduces the environmental risks, solving many deficiencies in the prior art. Summary of the Invention

[0005] In view of the above deficiencies in the prior art, the CO2 geological sequestration collaborative shale oil and geothermal energy green development system and method provided by the present invention construct a closed-loop system through innovative multiple uses of CO2, organically combining CO2 flooding and geothermal development, and solving the problems of CO2 leakage, environmental risks, and low economic benefits in the prior art.

[0006] To achieve the above invention object, the technical solution adopted by the present invention is: A CO2 geological sequestration collaborative shale oil and geothermal energy green development system, including a geothermal power station located on the ground, a ground cable, a first CO2 delivery pipeline, a CO2 injection device, a second CO2 delivery pipeline, a CO2 / shale oil separation device, a shale oil delivery pipeline, and a shale oil storage tank;

[0007] Among them, the geothermal power station is respectively connected to the CO2 injection device through the ground cable and the first CO2 delivery pipeline, the CO2 injection device is connected to the CO2 / shale oil separation device through the second CO2 delivery pipeline, and the CO2 / shale oil separation device is connected to the shale oil storage tank through the shale oil delivery pipeline;

[0008] Beneath the ground are successively an overlying layer, a shale oil reservoir, and a geothermal reservoir. The fracturing and transformation area of the geothermal reservoir is located in the geothermal reservoir, and the fracturing and transformation area of the shale oil reservoir is located in the shale oil reservoir. The CO2 injection device is connected to the input end of the CO2 injection well, and the output end of the CO2 injection well is located in the fracturing and transformation areas of the shale oil reservoir and the geothermal reservoir. The input end of the geothermal production well is located in the fracturing and transformation area of the geothermal reservoir, and 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 fracturing and transformation area of the shale oil reservoir, and the output end of the shale oil production well is connected to the CO2 / shale oil separation device;

[0009] The CO2 injection well is used to inject CO2 into the fracturing and transformation areas of the geothermal reservoir and the shale oil reservoir. The shale oil production well is used to collect the CO2 and shale oil mixture in the shale oil reservoir. The geothermal production well is used to collect the high-temperature CO2 in 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 and shale oil. The separated CO2 is input into the CO2 injection well through the second CO2 delivery pipeline, and the separated shale oil is input into the shale oil storage tank through the shale oil delivery pipeline.

[0010] Furthermore: The CO2 injection device is also successively connected to a CO2 capture device and a CO2 emission plant through the second CO2 delivery pipeline.

[0011] A CO2 geological sequestration collaborative shale oil and geothermal energy green development method, the method includes the following steps:

[0012] S1. Select a shale oil reservoir with rich shale oil reserves and a geothermal reservoir with rich geothermal resources as the target area;

[0013] S2. Inject high-pressure CO2 into the shale oil reservoir and the geothermal reservoir through a CO2 injection well, perform a fracturing operation, and establish a fracturing reform area for the shale oil reservoir and a fracturing reform area for the geothermal reservoir;

[0014] S3. After fracturing, continuously inject high-pressure CO2 through the CO2 injection well for oil displacement and heat extraction. Collect the CO2 and shale oil mixture through the shale oil production well, and collect high-temperature CO2 through the geothermal production well;

[0015] S4. Use the high-temperature CO2 for geothermal power generation through a geothermal power station to provide power for the CO2 injection device. Transport the low-temperature CO2 after power generation to the CO2 injection device through the first CO2 pipeline, and continue to inject it into the formation through the CO2 injection well for circulation;

[0016] S5. Based on the CO2 and shale oil mixture, separate the CO2 and shale oil through a CO2 / shale oil separation device. The separated CO2 is input into the CO2 injection well through the second CO2 pipeline, and the separated shale oil is input into the shale oil storage tank through the shale oil pipeline;

[0017] S6. Capture CO2 from the CO2 emission plant through a CO2 capture device and transport it to the CO2 injection well. Inject the CO2 into the fracturing reform area of the geothermal reservoir and the fracturing reform area of the shale oil reservoir through the CO2 injection well to form a complete closed loop of CO2 sequestration and energy extraction.

[0018] The beneficial effects of the present invention are as follows: The present invention provides a CO2 geological sequestration collaborative shale oil and geothermal energy green development system and method. By coupling the CO2 fracturing - CO2 displacement for shale oil extraction - CO2 cyclic extraction of the thermal reservoir system, a complete closed loop of CO2 sequestration and energy extraction is formed, improving the energy extraction efficiency, reducing energy consumption and carbon emissions, thereby effectively reducing the environmental pollution risk, which is different from the traditional single CO2 oil displacement technology.

[0019] The present invention combines the development of renewable energy (geothermal energy) with fossil energy (shale oil), and uses additional benefits such as shale oil development and carbon sequestration subsidies to overcome the problem of poor economy of the single CO2 geothermal extraction technology.

[0020] Through the multiple utilization of CO2 and the innovative closed loop, the present invention creates an efficient energy development system, which not only improves the recovery rate of shale oil, but also realizes the unity of economic benefits and environmental benefits through geothermal power generation and CO2 utilization and sequestration.

[0021] 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 enables CO2 to be injected into different reservoirs simultaneously, achieving efficient displacement of shale oil and efficient collection of geothermal energy, optimizing the wellbore layout and improving the efficiency of the overall system.

[0022] The present invention also has extremely high flexibility. If the shale oil reservoir is depleted in the later stage, the abandoned well of shale oil can be directly converted into a geothermal well for development and utilization, saving the costs of drilling and infrastructure transformation, and maximizing the utilization of existing infrastructure and resources. Brief Description of the Drawings

[0023] Figure 1 It is a schematic diagram of the CO2 geological sequestration collaborative green development system for shale oil and geothermal energy of the present invention.

[0024] Figure 2 It is a flow chart of the CO2 geological sequestration collaborative green development method for shale oil and geothermal energy of the present invention.

[0025] Figure 3 It is a process flow chart of the CO2 geological sequestration collaborative green development system for shale oil and geothermal energy of the present invention.

[0026] Among them: 1. Overlying layer; 2. Shale oil reservoir; 3. Geothermal reservoir; 4. Fracture transformation area of geothermal reservoir; 5. Fracture transformation area of shale oil reservoir; 6. Geothermal production well; 7. CO2 injection well; 8. Shale oil production well; 9. Geothermal power station; 10. Ground cable; 11. First CO2 transmission pipeline; 12. CO2 injection device; 13. Second CO2 transmission pipeline; 14. CO2 / shale oil separation device; 15. CO2 capture device; 16. CO2 emission plant; 17. Shale oil transmission pipeline; 18. Shale oil storage tank. Detailed Embodiments

[0027] The following describes the detailed embodiments of the present invention to facilitate those skilled in the art of the present technology to understand the present invention. However, it should be clear that the present invention is not limited to the scope of the detailed embodiments. For those of ordinary skill in the art of the present technology, as long as various changes are within the spirit and scope of the present invention defined and determined by the appended claims, these changes are obvious, and all inventions created using the concept of the present invention are within the scope of protection.

[0028] Such as Figure 1As shown in the figure, in one embodiment of the present invention, a CO2 geological storage collaborative shale oil and geothermal energy green development system includes 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;

[0029] Among them, the geothermal power station 9 is respectively connected to the CO2 injection device 12 through the ground cable 10 and the first CO2 transmission pipeline 11. The CO2 injection device 12 is connected to the CO2 / shale oil separation device 14 through the second CO2 transmission pipeline 13. The CO2 / shale oil separation device 14 is connected to the shale oil storage tank 18 through the shale oil transmission pipeline 17;

[0030] Below the ground, there are successively an overlying layer 1, a shale oil reservoir 2, and a geothermal reservoir 3. A fractured and reformed area 4 of the geothermal reservoir is located in the geothermal reservoir 3, and a fractured and reformed area 5 of the shale oil reservoir 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 fractured and reformed area 5 of the shale oil reservoir and the fractured and reformed area 4 of the geothermal reservoir. The input end of the geothermal production well 6 is located in the fractured and reformed area 4 of the geothermal reservoir. 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 fractured and reformed area 5 of the shale oil reservoir. The output end of the shale oil production well 8 is connected to the CO2 / shale oil separation device 14;

[0031] The fractured and reformed area 5 of the shale oil reservoir and the fractured and reformed area 4 of the geothermal reservoir 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 fractured and reformed area 4 of the geothermal reservoir and the fractured and reformed area 5 of the shale oil reservoir to realize the displacement of shale oil and the development of geothermal energy. The shale oil production well 8 is used to collect the CO2 and shale oil mixture in the shale oil reservoir 2. The geothermal production well 6 is used to collect the high-temperature CO2 in the geothermal reservoir 3. The geothermal power station 9 is used to generate electricity by using the collected high-temperature CO2. The CO2 / shale oil separation device 14 is used to separate CO2 and 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 extraction, 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.

[0032] The CO2 injection device 12 is also successively connected to a CO2 capture device 15 and a CO2 emission plant 16 through the second CO2 transmission pipeline 13.

[0033] In this embodiment, after the separated shale oil is processed, it is sent to the shale oil storage tank 18 through the shale oil pipeline 17 for storage or further processing. The geothermal power station 9 generates electricity using the high-temperature CO2 collected by the geothermal production well 6 and transmits the electricity to the CO2 injection device 12 or the power grid through the ground cable 10.

[0034] As Figures 2 - 3 shown, the method for the collaborative green development of shale oil and geothermal energy with CO2 geological storage includes the following steps:

[0035] S1. Select the shale oil reservoir 2 with rich shale oil reserves and the geothermal reservoir 3 with rich geothermal resources as the target areas;

[0036] In this embodiment, an area with rich shale oil and geothermal resources is selected as the target area. Through geological exploration, the reserves and locations 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.

[0037] S2. Inject high-pressure CO2 into the shale oil reservoir 2 and the geothermal reservoir 3 through the CO2 injection well 7 for fracturing operations to establish the shale oil reservoir fracturing and transformation area 5 and the geothermal reservoir fracturing and transformation area 4;

[0038] 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, enabling CO2 to be injected into different reservoirs simultaneously to achieve efficient displacement of shale oil and efficient collection of geothermal energy; production wells are respectively arranged in the shale oil reservoir 2 and the geothermal reservoir 3. The production well in the shale oil layer is used for shale oil displacement, and the production well in the geothermal reservoir 3 is used for geothermal energy extraction. The spacing and depth of the wellheads are designed according to specific geological conditions to ensure the efficient operation of the CO2 displacement and heat extraction processes. For depleted shale oil wells, they can be transformed into geothermal wells to save drilling costs and make full use of existing infrastructure. The initially injected CO2 is captured from the CO2 trading or CO2 emission factory 16. CO2 serves as the working medium, and a fracture network is formed through fracturing. The fractures enhance the reservoir permeability and provide an effective flow channel for the oil displacement and heat extraction of CO2.

[0039] S3. After fracturing, continuously inject high-pressure CO2 through the CO2 injection well 7 for oil displacement and heat extraction. Collect the CO2 and shale oil mixture through the shale oil production well 8, and collect high-temperature CO2 through the geothermal production well 6;

[0040] In this embodiment, after fracturing, continue to inject CO2 into the shale oil reservoir for oil displacement. CO2 dissolves the light components in the shale oil, reduces the viscosity of the oil, and improves its fluidity. During 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.

[0041] S4. Geothermal power generation is carried out by using high-temperature CO2 in the geothermal power station 9 to provide power for the CO2 injection device 12. The low-temperature CO2 after power generation is transported to the CO2 injection device 12 through the first CO2 pipeline 11 and then injected into the formation cycle through the CO2 injection well 7.

[0042] 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 electric energy generated can provide continuous power for CO2 injection, thus forming a closed energy utilization cycle. After power generation, the temperature of CO2 decreases, but it still has sufficient waste heat, which can be used for domestic heating, heating of oil pipelines, pipeline cleaning, etc., improving the comprehensive utilization efficiency of CO2 and maximizing the energy value of CO2.

[0043] S5. Based on the CO2 and shale oil mixture, the CO2 and shale oil are separated by the CO2 / shale oil separation device 14. The separated CO2 is input into the CO2 injection well 7 through the second CO2 pipeline 13, and the separated shale oil is input into the shale oil storage tank 18 through the shale oil pipeline 17.

[0044] S6. CO2 is captured from the CO2 emission plant 16 by the CO2 capture device 15 and transported to the CO2 injection well 7. The CO2 is cyclically injected into the fractured geothermal reservoir area 4 and the fractured shale oil reservoir area 5 through the CO2 injection well 7 to form a complete closed cycle of CO2 sequestration and energy extraction.

[0045] In this embodiment, the separated and captured CO2 is injected into the geothermal reservoir 3. The CO2 serves as the working fluid to extract the geothermal energy in the thermal reservoir. During this process, part of the CO2 is sequestered 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.

[0046] The beneficial effects of the present invention are as follows: The present invention provides a CO2 geological sequestration collaborative shale oil and geothermal energy green development system and method. By coupling the CO2 fracturing - CO2 displacement for shale oil extraction - CO2 cyclic extraction of the thermal reservoir system, a complete closed cycle of CO2 sequestration and energy extraction is formed, improving the energy extraction efficiency, reducing energy consumption and carbon emissions, and thus effectively reducing the environmental pollution risk, which is different from the traditional single CO2 flooding technology.

[0047] The present invention combines the development of renewable energy (geothermal energy) and fossil energy (shale oil), and overcomes the problem of poor economy of the single CO2 geothermal extraction technology by using additional benefits such as shale oil development and carbon sequestration subsidies.

[0048] The present invention creates an efficient energy development system through the multiple utilization of CO2 and an innovative closed cycle, which not only improves the recovery rate of shale oil, but also realizes the unity of economic benefits and environmental benefits through geothermal power generation and CO2 utilization and storage.

[0049] 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 enables CO2 to be injected into different reservoirs simultaneously, realizing the efficient displacement of shale oil and the efficient collection of geothermal energy, optimizing the wellbore layout and improving the efficiency of the overall system.

[0050] The present invention also has extremely high flexibility. If the shale oil reservoir is depleted in the later stage, the abandoned well of shale oil can be directly converted into a geothermal well for development and utilization, saving the costs of drilling and infrastructure transformation, and maximizing the utilization of existing infrastructure and resources.

[0051] In the description of the present invention, it should be understood 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 thus cannot be understood as a limitation to the present invention. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of technical features. Therefore, the features defined by "first", "second", "third" may explicitly or implicitly include one or more of such 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.

Images