A shale gas development system for comprehensive utilization of carbon dioxide

Abstract

The present invention provides a shale gas development system for comprehensively utilizing carbon dioxide, which is used for exploiting shale gas in shale layers and has the following characteristics: a supercritical carbon dioxide drilling system, a gas turbine power generation system, a supercritical carbon dioxide power generation system and a transcritical carbon dioxide refrigeration system are efficiently coupled, comprising: a supercritical carbon dioxide drilling system, which is used for exploiting and supplying shale gas, and comprises a carbon dioxide storage tank, a carbon dioxide high-pressure pump and a pipeline assembly; a gas turbine power generation system, which is used for burning shale gas and compressed air to generate high-temperature and high-pressure flue gas, and utilizes the high-temperature and high-pressure flue gas to expand and generate power, and the flue gas after the work is done still has residual heat; a supercritical carbon dioxide power generation system, which is used for converting the residual heat in the flue gas after the work is done into electrical energy; and a transcritical carbon dioxide refrigeration system, which is used for cooling the carbon dioxide of the supercritical carbon dioxide drilling system.

Description

Technical Field

[0001] The invention relates to a shale gas development system for comprehensively utilizing carbon dioxide, belonging to the technical field of energy development. Background Art

[0002] Energy is an indispensable element in economic production activities, and shale gas, as a clean and efficient energy resource, has a high development value. It is estimated that 85% of power generation resources in the future will come from natural gas, mainly shale gas. my country has abundant shale gas resources and broad development prospects. At present, efforts to promote shale gas exploration and development are being stepped up. At the same time, the large-scale use of fossil fuels has led to the continuous increase in greenhouse gas emissions, mainly carbon dioxide, causing a series of environmental problems. It has become an urgent task to promote the low-carbonization of the energy system and reduce carbon dioxide emissions.

[0003] Compared with other countries, China's numerous shale formations have undergone strong late-stage transformation. For example, in Sichuan and the Tarim Basin, most of the shale gas is buried at 4,000 to 6,000 meters, and the surface environment is poor, with many deserts. Water resources are generally used as the medium for fracturing, but this is not suitable for China, especially since China's shale gas will be developed in the northwest region where water resources are scarce in the future. If hydraulic fracturing is used, it will affect the porosity of the shale layer, the conductivity of the fractures, and reduce the recovery rate of shale gas. Hydraulic fracturing also has a certain pollution effect on water resources and cannot be used as the best choice for shale gas exploitation.

[0004] In addition, shale gas currently needs to be stored and transported to other areas for utilization after extraction, and transportation also increases costs. Summary of the invention

[0005] The present invention is made to solve the above problems, and its purpose is to provide a shale gas development system that comprehensively utilizes carbon dioxide. To this end, the present invention provides the following technical solutions:

[0006] The present invention provides a shale gas development system for comprehensively utilizing carbon dioxide, which is used for exploiting shale gas in a shale layer and has the following characteristics: a supercritical carbon dioxide drilling system, a gas turbine power generation system, a supercritical carbon dioxide power generation system and a transcritical carbon dioxide refrigeration system are efficiently coupled, and include: a supercritical carbon dioxide drilling system, which is used for exploiting and supplying shale gas, and comprises a carbon dioxide storage tank, a carbon dioxide high-pressure pump and a pipeline assembly; a gas turbine power generation system, which is used for burning shale gas and compressed air to generate high-temperature and high-pressure flue gas, and utilizing the high-temperature and high-pressure flue gas to expand and generate power, and the flue gas after the work is done still has residual heat; a supercritical carbon dioxide power generation system, which is used for converting the residual heat in the flue gas after the work is done into electrical energy; and a transcritical carbon dioxide refrigeration system, which is used for cooling the carbon dioxide in the carbon dioxide storage tank, wherein the carbon dioxide storage tank in the supercritical carbon dioxide drilling system is used for storing supercritical carbon dioxide in a low-temperature liquid state, the carbon dioxide high-pressure pump sends the supercritical carbon dioxide to the shale layer through the pipeline assembly, the pipeline assembly collects the shale gas in the shale layer and supplies it to the gas turbine power generation system, and the gas turbine power generation system supplies power to the transcritical carbon dioxide refrigeration system.

[0007] The shale gas development system for comprehensive utilization of carbon dioxide provided by the present invention may also have the following features: wherein the gas turbine power generation system includes a compressor, a burner, a turbine mechanism and a first generator, the compressor is used to compress air, the burner is used to burn the compressed air with shale gas to generate a large amount of high-temperature and high-pressure flue gas, the high-temperature and high-pressure flue gas drives the first generator to generate electricity through the turbine mechanism, and the first generator supplies power to the compressor and the transcritical carbon dioxide refrigeration system and stores the remaining electrical energy.

[0008] The shale gas development system for comprehensive utilization of carbon dioxide provided by the present invention may also have the following features: wherein the transcritical carbon dioxide refrigeration system comprises a transcritical carbon dioxide storage tank, a transcritical carbon dioxide compressor and an air cooler, the transcritical carbon dioxide storage tank is used to store transcritical carbon dioxide, the transcritical carbon dioxide compressor is used to compress carbon dioxide, the air cooler is used to cool carbon dioxide, and the refrigerator is used to cool the carbon dioxide in the carbon dioxide storage tank in the supercritical carbon dioxide drilling system by heat conduction.

[0009] The shale gas development system for comprehensive utilization of carbon dioxide provided by the present invention may also have the following features: wherein the transcritical carbon dioxide refrigeration system further includes a first regenerator, and the first regenerator is used to absorb heat at the outlet of the air cooler.

[0010] The shale gas development system for comprehensive utilization of carbon dioxide provided by the present invention may also have the following characteristics: the heat absorption process of transcritical carbon dioxide in the transcritical carbon dioxide compressor is in the subcritical region, and the heat release process in the air cooler is in the supercritical region.

[0011] The shale gas development system for comprehensive utilization of carbon dioxide provided by the present invention may also have the following features: wherein, the supercritical carbon dioxide power generation system comprises a supercritical carbon dioxide storage tank, an electric motor, a supercritical carbon dioxide compressor, an electric motor, a heat exchanger, a supercritical carbon dioxide expander, a second generator and a cooler, the supercritical carbon dioxide storage tank is used to store supercritical carbon dioxide, the electric motor provides power to the supercritical carbon dioxide compressor, the supercritical carbon dioxide compressor is used to compress supercritical carbon dioxide, the heat exchanger is used to allow the supercritical carbon dioxide to absorb residual heat in the flue gas that has done work, the supercritical carbon dioxide expander and the generator are used to utilize the carbon dioxide after absorbing heat to expand and generate electricity, and the cooler is used to cool the supercritical carbon dioxide that has done work.

[0012] The shale gas development system for comprehensive utilization of carbon dioxide provided by the present invention may also have the following characteristics: wherein the supercritical carbon dioxide power generation system also includes a second regenerator for absorbing heat at the outlet of the supercritical carbon dioxide expander and transferring heat to the carbon dioxide at the outlet of the supercritical carbon dioxide compressor.

[0013] The shale gas development system for comprehensive utilization of carbon dioxide provided by the present invention may also have the following feature: the cooler performs cooling by heat conduction using air.

[0014] The shale gas development system for comprehensive utilization of carbon dioxide provided by the present invention may also have the following characteristics: wherein the cooler is connected to the transcritical carbon dioxide refrigeration system to form a loop to achieve cooling of supercritical carbon dioxide.

[0015] The shale gas development system for comprehensive utilization of carbon dioxide provided by the present invention may also have the following features: wherein, the pipeline assembly also includes a continuous oil pipe, a casing, a director, a whipstock, a production casing, a flexible pipe and a supercritical carbon dioxide injection rotor; one end of the continuous oil pipe is connected to the carbon dioxide high-pressure pump, and the other end is connected to the flexible pipe and the production casing through the casing; the director and the whipstock are installed in the casing; the director and the whipstock are used to bend the flexible pipe within a certain range and change the vertical direction to the horizontal direction at the bottom of the wellbore; the supercritical carbon dioxide injection rotor is installed on the other end of the flexible pipe for sending supercritical carbon dioxide to the shale layer; the other end of the production casing is arranged in the shale layer for collecting shale gas.

[0016] Functions and Effects of the Invention

[0017] The shale gas development system for comprehensive utilization of carbon dioxide involved in the present invention includes a supercritical carbon dioxide drilling system, a gas turbine power generation system, a supercritical carbon dioxide power generation system and a transcritical carbon dioxide refrigeration system. These systems have the following effects:

[0018] The supercritical carbon dioxide drilling system delivers supercritical carbon dioxide to shale layers. Since supercritical carbon dioxide has liquid-like high density, strong solvation ability, and low viscosity, shale's adsorption capacity for carbon dioxide is 4-20 times that of shale gas. Therefore, the use of supercritical carbon dioxide for mining can achieve the same effect as hydraulic fracturing, creating micro-cracks in the rock formation, connecting natural cracks, increasing the porosity of the shale layer, improving the shale gas conductivity, and increasing the single-well production and recovery rate of the gas well.

[0019] The gas turbine power generation system directly uses the collected shale gas as energy to generate electricity and stores excess energy.

[0020] The supercritical carbon dioxide power generation system absorbs the heat of the flue gas produced by the combustion of shale gas through supercritical carbon dioxide, which expands to generate electricity. After the work is done, the supercritical carbon dioxide is cooled and returns to its original state, which can be recycled.

[0021] The transcritical carbon dioxide refrigeration system uses carbon dioxide to cool the carbon dioxide in the carbon dioxide storage tank in the supercritical carbon dioxide drilling system through heat conduction and then returns it to its original state. The carbon dioxide can be recycled.

[0022] Therefore, the present invention is more effective than traditional methods in exploiting shale gas. Due to the use of the transcritical carbon dioxide refrigeration system and the supercritical carbon dioxide power generation system in the present invention, the exploited shale gas can be used on-site for energy conversion, and at the same time, the exploitation of shale gas is freed from the constraints of water, which is particularly suitable for shale gas exploitation in areas with water scarcity. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a system connection diagram of a shale gas development system for comprehensive utilization of carbon dioxide in Embodiment 1 of the present invention;

[0024] Figure 2 This is a system connection diagram of a shale gas development system for comprehensive utilization of carbon dioxide in Embodiment 2 of the present invention;

[0025] Figure 3 is a system connection diagram of a shale gas development system for comprehensive utilization of carbon dioxide in Embodiment 3 of the present invention; and

[0026] Figure 4 It is a system connection diagram of a shale gas development system for comprehensive utilization of carbon dioxide in Example 4 of the present invention. DETAILED DESCRIPTION

[0027] In order to make the technical means, creative features, objectives and effects of the present invention easy to understand, the following embodiments and accompanying drawings specifically illustrate the shale gas development system for comprehensive utilization of carbon dioxide of the present invention.

[0028] <Example 1>

[0029] Figure 1 is a system diagram of a shale gas development system for comprehensive utilization of carbon dioxide in Embodiment 1 of the present invention;

[0030] like Figure 1 As shown, the shale gas development system 100 for comprehensive utilization of carbon dioxide includes a supercritical carbon dioxide drilling system 10, a gas turbine power generation system 20, a supercritical carbon dioxide power generation system 30 and a transcritical carbon dioxide refrigeration system 40.

[0031] The supercritical carbon dioxide drilling system 10 includes a carbon dioxide storage tank 11, a pressure balance tank 12, a carbon dioxide high-pressure pump 13 and a pipeline assembly. The pipeline assembly also includes a continuous oil pipe 14, a casing 141, a director 142, a whipstock 143, a production casing 15, a flexible pipe 16 and a supercritical carbon dioxide injection rotor 17.

[0032] The carbon dioxide storage tank 11 can store carbon dioxide, and the pressure balance tank 12 can maintain the gas pressure in the tank at 2MPa-4MPa. The continuous oil pipe 14 enters the well through the wellhead 1. One end of the continuous oil pipe is connected to the carbon dioxide high-pressure pump 13, and the other end is connected to the production casing 15 and the flexible pipe 16 through the casing 141. The orienter 142 and the whipstock 143 set in the casing 141 can make the flexible pipe 16 bend within a certain range and change from a vertical direction to a horizontal direction at the bottom of the wellbore. The other end of the flexible pipe 16 is equipped with a supercritical carbon dioxide injection rotor 17. The carbon dioxide high-pressure pump 13 sends the carbon dioxide in the carbon dioxide storage tank 11 to the shale layer through the pipeline assembly to displace the shale gas. The production casing 15 collects the mined shale gas and sends it to the gas turbine power generation system 20.

[0033] The gas turbine power generation system 20 includes an air compressor 21 , a generator 22 , a combustor 23 , and a turbine mechanism 24 .

[0034] The air is compressed by the air compressor 21 and then enters the burner 23 to be mixed with the shale gas sent to the burner 23 by the production casing 15 for combustion. After combustion, the high-temperature and high-pressure flue gas generated enters the turbine mechanism 24 to expand and do work. The turbine mechanism 24 drives the air compressor 21, and the excess energy is recovered and stored by the generator 22.

[0035] The supercritical carbon dioxide power generation system 30 includes a supercritical carbon dioxide storage tank 31 , a motor 32 , a supercritical carbon dioxide compressor 33 , a heat exchanger 34 , a supercritical carbon dioxide expander 35 , a generator 36 and a cooler 37 .

[0036] The supercritical carbon dioxide stored in the supercritical carbon dioxide storage tank 31 enters the supercritical carbon dioxide compressor 33 driven by the motor 32 for compression, and is sent to the heat exchanger 34 to absorb the residual heat of the flue gas generated by the gas turbine power generation system 20. The supercritical carbon dioxide carries the heat into the supercritical carbon dioxide expander 35, and the expansion work drives the generator 36 to generate electricity. The supercritical carbon dioxide that has completed the work enters the cooler 37, is cooled by air, and returns to the supercritical carbon dioxide storage tank 31 after cooling, completing a cycle.

[0037] The transcritical carbon dioxide refrigeration system 40 includes a transcritical carbon dioxide storage tank 41 , a transcritical carbon dioxide compressor 42 , an air cooler 43 , a throttle valve 44 and a refrigerator 45 .

[0038] The carbon dioxide in the transcritical carbon dioxide storage tank 41 is compressed in the transcritical carbon dioxide compressor 42 driven by the gas turbine power generation system 20, and then enters the air cooler 43 for cooling. The cooled carbon dioxide enters the throttle valve 44, and the carbon dioxide at the outlet of the throttle valve 44 enters the refrigerator 45 to cool the carbon dioxide in the carbon dioxide storage tank 11 by heat conduction, and the temperature is controlled at -20℃-0℃. The heated carbon dioxide returns to the transcritical carbon dioxide storage tank 41, completing a cycle.

[0039] Functions and Effects of Embodiment 1

[0040] The shale gas development system for comprehensive utilization of carbon dioxide involved in this embodiment 1 includes a supercritical carbon dioxide drilling system, a gas turbine system, a supercritical carbon dioxide power generation system and a transcritical carbon dioxide refrigeration system. These structures have the following effects:

[0041] The supercritical carbon dioxide drilling system is used to extract and supply natural gas, including carbon dioxide storage tanks, carbon dioxide high-pressure pumps and pipeline components. The pressure of carbon dioxide in the carbon dioxide storage tank is 2MPa-4MPa, the pressure is maintained by the pressure balance tank, and the temperature is -20℃-0℃, which is maintained by the refrigerator in the transcritical carbon dioxide refrigeration system. The pipeline components include continuous tubing, direction finder, whipstock, flexible pipe, production casing and supercritical carbon dioxide jet rotor. The director and whipstock are installed at the bottom of the continuous oil pipe, the production casing and the flexible pipe installation set are installed on the continuous oil pipe, and a supercritical carbon dioxide injection rotor is installed at the bottom of the flexible pipe. The carbon dioxide is sent to the shale layer through the pipeline assembly by a carbon dioxide high-pressure pump. Since carbon dioxide has high density, strong solvation ability and low viscosity similar to liquid, the adsorption capacity of shale for carbon dioxide is 4-20 times that of shale gas. Therefore, the use of supercritical carbon dioxide for mining can achieve the same effect as hydraulic fracturing, causing micro-cracks in the rock formation, connecting natural cracks, and increasing the porosity of the shale layer. The conductivity of shale gas and the single well production and recovery rate of the gas well are increased. The collected shale gas is sent to the burner in the gas turbine power generation system through the pipeline assembly. At the same time, the carbon dioxide sent to the shale layer will be sealed in the shale layer, reducing the carbon dioxide in the atmosphere, which has a certain effect on reducing the greenhouse effect.

[0042] The gas turbine power generation system includes an air compressor, a burner, a turbine mechanism, and a generator. After the air is compressed by the air compressor, it reacts with the shale gas sent to the burner to produce high-temperature and high-pressure flue gas. The high-temperature and high-pressure flue gas drives the turbine mechanism to rotate and drives the generator to generate electricity. Since the air is compressed by the air compressor, the oxygen content per unit volume also increases, so that the shale gas can be fully burned and generate a lot of heat. At the same time, the generator is used to store excess energy to achieve full utilization of energy.

[0043] The supercritical carbon dioxide power generation system includes a supercritical carbon dioxide storage tank, a supercritical carbon dioxide compressor, a heat exchanger, a supercritical carbon dioxide expander, a generator and a cooler. The flue gas that has done work in the gas turbine power generation system still has residual heat. The supercritical carbon dioxide in the supercritical carbon dioxide storage tank is compressed by the supercritical carbon dioxide compressor and then enters the heat exchanger to further absorb the residual heat in the flue gas that has done work. The carbon dioxide that has absorbed the heat enters the supercritical carbon dioxide expander to expand and do work to drive the generator to generate electricity. The cooler uses air to cool the carbon dioxide that has done work, and after cooling, it returns to the supercritical carbon dioxide storage tank to complete a cycle. The supercritical carbon dioxide power generation system uses the residual heat in the flue gas that has done work to generate electricity, improve energy utilization, and use it locally, reducing the transportation cost of shale gas and the loss of shale gas during transportation. The integrated design is more convenient and efficient.

[0044] The transcritical carbon dioxide refrigeration system includes a transcritical carbon dioxide storage tank, a transcritical carbon dioxide compressor, an air cooler, and a refrigerator. The turbine mechanism of the gas turbine power generation system synchronously drives the transcritical carbon dioxide compressor to compress the carbon dioxide from the transcritical carbon dioxide storage tank. The compressed carbon dioxide enters the air cooler for cooling, and then enters the refrigerator to cool the carbon dioxide in the carbon dioxide storage tank of the supercritical carbon dioxide drilling system by heat conduction. The carbon dioxide that absorbs heat returns to the transcritical carbon dioxide storage tank, completing a cycle. The transcritical carbon dioxide refrigeration system maintains the temperature in the carbon dioxide storage tank at -20℃-0℃, increasing the efficiency of shale gas extraction. At the same time, the carbon dioxide in the transcritical carbon dioxide refrigeration system can be recycled, which will not cause waste of resources and greenhouse gas emissions, making the entire shale gas development system green and environmentally friendly.

[0045] Therefore, the supercritical carbon dioxide drilling system, transcritical carbon dioxide refrigeration system and supercritical carbon dioxide power generation system included in this invention make shale gas extraction have higher benefits and effects compared with traditional methods. At the same time, on-site utilization not only reduces production costs, but also makes the shale gas development process more green and environmentally friendly.

[0046] <Example 2>

[0047] Figure 2 It is a system diagram of a shale gas development system for comprehensive utilization of carbon dioxide in Example 2 of the present invention. For ease of expression, in this embodiment, the same symbols are given to the same structures as in Example 1, and the same descriptions are omitted.

[0048] Compared with the first embodiment, the second embodiment adds a first heat regenerator in the closed loop of the transcritical carbon dioxide refrigeration system and a second heat regenerator in the closed loop of the supercritical carbon dioxide power generation system.

[0049] In this embodiment, the carbon dioxide coming out of the transcritical carbon dioxide storage tank 41 enters the first regenerator 46 to absorb the heat at the outlet of the air cooler, and then enters the transcritical carbon dioxide compressor 42 for compression. The high-pressure carbon dioxide enters the air cooler 43 and the first regenerator 46 for cooling. The cooled carbon dioxide enters the throttle valve 44. The carbon dioxide at the outlet of the throttle valve 44 enters the refrigerator 45 to cool the carbon dioxide in the drilling system carbon dioxide storage tank 11. The heated carbon dioxide returns to the transcritical carbon dioxide storage tank 41 to complete a cycle.

[0050] The carbon dioxide coming out of the supercritical carbon dioxide storage tank 31 enters the supercritical carbon dioxide compressor 33 for compression and first absorbs the heat at the outlet of the supercritical carbon dioxide expander 35 in the second regenerator 38, and then enters the heat exchanger 34 to absorb the heat of the flue gas. The high-temperature and high-pressure carbon dioxide enters the supercritical carbon dioxide expander 35 to expand and do work. The carbon dioxide that has done the work enters the second regenerator 38 to transfer the heat to the carbon dioxide at the outlet of the supercritical carbon dioxide compressor 33, and then enters the cooler 37 to be cooled and then returns to the carbon dioxide storage tank 31 to complete a cycle.

[0051] Functions and Effects of Embodiment 2

[0052] The same structure as in the first embodiment has the same effect in the second embodiment, and will not be described in detail here.

[0053] In the second embodiment, a first regenerator is provided in the transcritical carbon dioxide refrigeration system. Before the carbon dioxide enters the transcritical carbon dioxide compressor for compression, it first absorbs the heat of the carbon dioxide at the cooler outlet, so that the carbon dioxide is fully cooled, thereby improving the effect of the refrigerator and further increasing the production of shale gas.

[0054] In the second embodiment, a second heat regenerator is provided in the supercritical carbon dioxide power generation system. Before the supercritical carbon dioxide enters the heat exchanger, it first absorbs the heat at the outlet of the supercritical carbon dioxide expander, and then absorbs the residual heat of the flue gas in the heat exchanger. The residual heat of the flue gas is further utilized on-site, thereby reducing heat loss, reducing the impact on the surrounding environment, and making the process of shale gas development green and environmentally friendly.

[0055] <Example 3>

[0056] Figure 3 This is a system diagram of a shale gas development system for comprehensive utilization of carbon dioxide in Example 3 of the present invention. For ease of expression, in this embodiment, the same symbols are given to the same structures as in Example 1, and the same descriptions are omitted.

[0057] In the first embodiment, the cooler uses air to cool the supercritical carbon dioxide that has completed work in the supercritical carbon dioxide expander, while in this embodiment, carbon dioxide from a transcritical carbon dioxide refrigeration system is used instead of air to cool the supercritical carbon dioxide that has completed work in the supercritical carbon dioxide expander.

[0058] In this embodiment, the transcritical carbon dioxide in the transcritical carbon dioxide storage tank 41 is compressed by the transcritical carbon dioxide compressor 42, and then enters the air cooler 43 for cooling. The cooled transcritical carbon dioxide passes through the throttle valve 44 and enters the supercritical carbon dioxide cooler 37 to cool the supercritical carbon dioxide at the outlet of the supercritical carbon dioxide expander 35 by heat conduction, and then enters the refrigerator 45 to cool the carbon dioxide in the drilling system carbon dioxide storage tank 11 by heat conduction. The carbon dioxide after absorbing heat returns to the transcritical carbon dioxide storage tank 41 to complete a cycle.

[0059] Functions and Effects of Embodiment 3

[0060] The same structure as in the first embodiment has the same effect in the third embodiment, and will not be described in detail here.

[0061] In the third embodiment, the cooler of the supercritical carbon dioxide power generation system does not use air to cool the supercritical carbon dioxide that has done work, but uses the carbon dioxide in the transcritical carbon dioxide refrigeration system to cool the supercritical carbon dioxide that has done work. Compared with air, the carbon dioxide in the transcritical carbon dioxide refrigeration system has better heat conduction efficiency and effect, which accelerates the cooling of the supercritical carbon dioxide and improves the power generation efficiency of the supercritical carbon dioxide power generation system.

[0062] <Example 4>

[0063] Figure 4 This is a system diagram of a shale gas development system for comprehensive utilization of carbon dioxide in Embodiment 4 of the present invention. For ease of expression, the same symbols are given to the same structures in this embodiment as those in Embodiment 1, and the same descriptions are omitted.

[0064] Compared with Example 1, Example 4 integrates the two schemes of Example 2 and Example 3, adds a first heat regenerator in the closed loop of the transcritical carbon dioxide refrigeration system and a second heat regenerator in the closed loop of the supercritical carbon dioxide power generation system, and at the same time, in this Example 4, the carbon dioxide of the transcritical carbon dioxide refrigeration system is used instead of air to cool the supercritical carbon dioxide that has done work in the supercritical carbon dioxide expander.

[0065] The carbon dioxide coming out of the transcritical carbon dioxide storage tank 41 enters the regenerator 46 to absorb the heat at the outlet of the cooler 37, and then enters the transcritical carbon dioxide compressor 42 for compression. The high-pressure carbon dioxide enters the air cooler 43 for cooling. The cooled carbon dioxide enters the supercritical carbon dioxide cooler 37 to cool the working fluid at the outlet of the supercritical carbon dioxide expander 35, and then enters the heat exchanger 46 for cooling. Finally, it passes through the throttle valve 44 and enters the refrigerator 45 to cool the carbon dioxide in the drilling system carbon dioxide storage tank 11. The heated carbon dioxide returns to the transcritical carbon dioxide storage tank 41 to complete a cycle.

[0066] The carbon dioxide coming out of the supercritical carbon dioxide storage tank 31 enters the supercritical carbon dioxide compressor 33 for compression and first absorbs the heat at the outlet of the supercritical carbon dioxide expander 35 in the supercritical carbon dioxide regenerator 38, and then enters the heat exchanger 34 to absorb the heat of the flue gas. The high-temperature and high-pressure carbon dioxide enters the supercritical carbon dioxide expander 35 to expand and do work. The carbon dioxide that has done the work enters the supercritical carbon dioxide regenerator 38 to transfer the heat to the carbon dioxide at the outlet of the supercritical carbon dioxide compressor 33, and then enters the cooler 37 to be cooled and then returns to the carbon dioxide storage tank 31 to complete a cycle.

[0067] Functions and Effects of Embodiment 4

[0068] The same structure as in the first embodiment has the same effect in the fourth embodiment, and will not be described in detail here.

[0069] In the fourth embodiment, the carbon dioxide from the transcritical carbon dioxide storage tank enters the regenerator to absorb the heat at the cooler outlet, then enters the transcritical carbon dioxide compressor for compression and enters the air cooler for cooling, then enters the supercritical carbon dioxide cooler to cool the working fluid at the supercritical carbon dioxide expander outlet, then enters the heat exchanger for cooling, and finally enters the refrigerator through the throttle valve to cool the carbon dioxide in the drilling system carbon dioxide storage tank, and the heated carbon dioxide returns to the transcritical carbon dioxide storage tank. A better closed loop is formed to make full use of energy and improve the effect of the refrigerator.

[0070] In the fourth embodiment, after the supercritical carbon dioxide enters the supercritical carbon dioxide compressor for compression, it first absorbs heat from the outlet of the supercritical carbon dioxide expander in the supercritical carbon dioxide regenerator, and then enters the heat exchanger to absorb heat from the flue gas. The high-temperature and high-pressure carbon dioxide enters the supercritical carbon dioxide expander to expand and do work. The carbon dioxide that has done the work enters the supercritical carbon dioxide regenerator to transfer heat to the carbon dioxide at the outlet of the supercritical carbon dioxide compressor, and then enters the cooler to be cooled and then returns to the carbon dioxide storage tank, thereby making full use of the residual heat in the flue gas and improving the power generation efficiency.

[0071] The above-mentioned embodiments are preferred examples of the present invention and are not intended to limit the protection scope of the present invention.

Claims

1. A shale gas development system for comprehensive utilization of carbon dioxide, used for shale gas in shale layers, characterized in that Efficiently couple the supercritical CO2 drilling system, gas turbine power generation system, supercritical CO2 power generation system and transcritical CO2 refrigeration system, including: The supercritical carbon dioxide drilling system is used to exploit and supply shale gas, and includes a carbon dioxide storage tank, a carbon dioxide high-pressure pump, and a pipeline assembly; The gas turbine power generation system is used for the combustion of the shale gas and compressed air to generate high-temperature and high-pressure flue gas, and the high-temperature and high-pressure flue gas is used to expand to generate power, and the flue gas still has residual heat after the work is done; The supercritical carbon dioxide power generation system is used to convert the residual heat in the flue gas that has completed the work into electrical energy; The transcritical carbon dioxide refrigeration system is used to cool the carbon dioxide in the carbon dioxide storage tank. Among them, the carbon dioxide storage tank in the supercritical carbon dioxide drilling system is used to store low-temperature liquid supercritical carbon dioxide, the carbon dioxide high-pressure pump sends supercritical carbon dioxide to the shale layer through the pipeline assembly, the pipeline assembly collects shale gas in the shale layer and supplies it to the gas turbine power generation system, and the gas turbine power generation system provides power for the transcritical carbon dioxide refrigeration system.

2. The shale gas development system for comprehensive utilization of carbon dioxide according to claim 1, characterized in that: in, The gas turbine power generation system comprises a compressor, a combustor, a turbine mechanism and a first generator. The compressor is used to compress air. The burner is used for burning the compressed air and the shale gas to generate a large amount of high-temperature and high-pressure flue gas. The high-temperature and high-pressure flue gas drives the first generator to generate electricity through the turbine mechanism. The first generator supplies power to the compressor and the transcritical carbon dioxide refrigeration system and stores the remaining electrical energy.

3. The shale gas development system for comprehensive utilization of carbon dioxide according to claim 1, characterized in that: in, The transcritical carbon dioxide refrigeration system comprises a transcritical carbon dioxide storage tank, a transcritical carbon dioxide compressor, an air cooler and a refrigerator. The transcritical carbon dioxide storage tank is used to store carbon dioxide in a transcritical carbon dioxide refrigeration system. The transcritical carbon dioxide compressor is used to compress carbon dioxide in a transcritical carbon dioxide refrigeration system. The air cooler is used to cool carbon dioxide in a transcritical carbon dioxide refrigeration system. The refrigerator is used to cool the carbon dioxide in the carbon dioxide storage tank in the supercritical carbon dioxide drilling system by heat conduction.

4. The shale gas development system for comprehensive utilization of carbon dioxide according to claim 3 is characterized in that: in, The transcritical carbon dioxide refrigeration system further includes a first regenerator, which is used to absorb heat at the outlet of the air cooler.

5. The shale gas development system for comprehensive utilization of carbon dioxide according to claim 3 is characterized by: in, The heat absorption process of the carbon dioxide in the transcritical carbon dioxide compressor is in the subcritical region, and the heat release process in the air cooler is in the supercritical region.

6. The shale gas development system for comprehensive utilization of carbon dioxide according to claim 1, characterized in that: in, The supercritical carbon dioxide power generation system comprises a supercritical carbon dioxide storage tank, a motor, a supercritical carbon dioxide compressor, a motor, a heat exchanger, a supercritical carbon dioxide expander, a second generator and a cooler. The supercritical carbon dioxide storage tank is used to store supercritical carbon dioxide. The electric motor provides power to the supercritical carbon dioxide compressor. The supercritical carbon dioxide compressor is used to compress supercritical carbon dioxide. The heat exchanger is used to allow the supercritical carbon dioxide to absorb the residual heat in the flue gas that has done work. The supercritical carbon dioxide expander and the generator are used to generate electricity by utilizing the expansion of carbon dioxide after absorbing heat. The cooler is used to cool the supercritical carbon dioxide that has done work.

7. The shale gas development system for comprehensive utilization of carbon dioxide according to claim 6, characterized in that: in, The supercritical carbon dioxide power generation system also includes a second regenerator for absorbing heat at the outlet of the supercritical carbon dioxide expander and transferring heat to the carbon dioxide at the outlet of the supercritical carbon dioxide compressor.

8. The shale gas development system for comprehensive utilization of carbon dioxide according to claim 6, characterized in that: in, The cooler performs cooling by heat conduction through air.

9. The shale gas development system for comprehensive utilization of carbon dioxide according to claim 6, characterized in that: in, The cooler is connected to the transcritical carbon dioxide refrigeration system to form a loop to achieve cooling of supercritical carbon dioxide.

10. The shale gas development system for comprehensive utilization of carbon dioxide according to claim 1, characterized in that: in, The pipeline assembly also includes a coiled tubing, a casing, a direction finder, a whipstock, a production casing, a flexible pipe, and a supercritical carbon dioxide injection rotor. One end of the coiled tubing is connected to the carbon dioxide high-pressure pump, and the other end is connected to the flexible pipe and the production casing through the casing, wherein the orienter and the whipstock are mounted in the casing. The orienter and the whipstock are used to bend the flexible pipe within a certain range, and change the vertical direction to the horizontal direction at the bottom of the wellbore. The supercritical carbon dioxide injection rotor is mounted on the other end of the flexible pipe to deliver supercritical carbon dioxide to the shale layer. One end of the production casing is arranged in the shale layer for collecting shale gas.

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