Gravity-compressed gas energy storage system and method depending on waste oil and gas well

Abstract

The invention belongs to the technical field of power generation and energy storage systems, and discloses a gravity-compressed gas energy storage system and method depending on a waste oil and gas well. The system comprises a compressed gas energy storage device, a waste oil and gas well and a gravity energy storage device which are sequentially connected. The compressed gas energy storage device comprises a compression device and a high-pressure container; the high-pressure container is connected with a waste oil-gas well; a piston is installed in a shaft of the waste oil and gas well, gas is arranged above the piston, and water is arranged below the piston. The bottom of the waste oil-gas well is connected with a water injection pipe and a water return pipe; the water injection pipe and the water return pipe are connected with the reversible pump turbine; the reversible pump turbine is connected with the ground reservoir through a water pipe and is in driving connection with the generator set. The gravity energy storage device and the compressed air energy storage device are built in the underground space of a large number of waste oil and gas wells, resources are fully saved and integrated, the energy utilization rate is increased, and operation is easy, reliable and practical.

Description

Technical Field

[0001] The present invention belongs to the technical field of power generation and energy storage systems, and in particular relates to a gravity-compressed gas energy storage system and method based on abandoned oil and gas wells. Background Art

[0002] At present, there are a large number of abandoned oil and gas wells in my country. In order to give full play to their value, reduce environmental pollution and improve energy utilization, they can be used in gravity energy storage to give full play to their secondary value.

[0003] In the prior art, patent document CN201599160U discloses a large-capacity gravity energy storage device for power stations, including: a counterweight body, the counterweight body is used to be lifted to a high altitude so as to convert electrical energy into the gravitational potential energy increased by the counterweight body; a support device, including a support column and a beam erected on the support column; an electric lifting device, the electric lifting device at least includes a motor, a winding wheel shaft driven by the motor, a pulley arranged above the counterweight body, and a cable passing around the pulley in the middle, one end of the cable is fixed to the support device, and the other end is fixed to the winding wheel shaft; a power generation device, including a generator, the generator is connected to the winding wheel shaft through a transmission member to convert the gravitational potential energy of the counterweight body into electrical energy. The technical solution of this patent can realize ultra-large capacity energy storage, with the advantages of high energy density, small footprint, high energy cycle efficiency, and small limitations. However, the technical solution of this patent requires a large support column structure, which consumes a high cost. At the same time, the large support column structure standing on the ground is easily disturbed by external environmental factors such as wind and rain, and the safety factor and reliability are low.

[0004] Patent document CN209676010U discloses a gravity energy storage system based on a coal mine, including a weight arranged in a vertical shaft of the mine and an energy storage and release mechanism corresponding to the weight, wherein the energy storage and release mechanism is connected to a power grid. The technical solution of this patent uses the abandoned coal mine shaft for the gravity energy storage system, and discloses the energy conversion between electrical energy and gravitational potential energy by transferring potential energy through water and sinking and floating of heavy objects. However, in the technical solution of this patent, since the sinking and floating of an object is related to the weight and volume of the object itself, as well as the density, viscosity and flow rate (kinetic energy impact force of water) of the fluid carrying the heavy object, when the technical solution of this patent uses water to transfer potential energy, in the process of floating the heavy object by water pumping, it is not only necessary to consider the buoyancy of the object, but also the weight and volume of the heavy object, the pumping flow rate of water, the changes in the density and viscosity of water caused by the change in water pressure, and the influence of the change in buoyancy, etc. At the same time, it is also necessary to consider whether the heavy object can remain floating after the water stops pumping after the heavy object floats up, and the kinetic energy impact force of the water disappears, and the buoyancy will also decrease. That is, the potential energy stored when the technical solution is implemented is affected by many factors, and its energy storage is limited. The reliability and practicality of the energy storage method need to be further discussed.

[0005] Gravity energy storage and compressed air energy storage are new energy storage technologies. The former uses heavy objects as energy storage media, has a simple principle and various forms, and can give full play to different geographical advantages for energy storage; the latter converts mechanical energy into the internal energy of the air through mechanical work, and drives the turbine generator to work through high-pressure gas when releasing energy. Compared with traditional energy storage technologies, gravity energy storage and compressed air energy storage technologies have very obvious advantages. However, gravity energy storage requires a large potential energy difference, while compressed air energy storage requires a larger high-pressure storage container, and both are subject to more restrictions. Summary of the invention

[0006] The present invention aims to solve at least one technical problem existing in the background technology, and provides a gravity-compressed gas energy storage system and method based on abandoned oil and gas wells, which utilizes the underground space of a large number of abandoned oil and gas wells to build gravity energy storage and compressed air energy storage devices, and integrates gravity energy storage and compressed air energy storage for utilization. It can fully utilize the deep space of a large number of abandoned oil and gas wells and save the investment in building high platforms on the ground, and can also take into account the larger potential energy difference required for gravity energy storage and the larger high-pressure storage containers required for compressed air storage, fully saving and integrating resources, improving energy utilization, and is simple, reliable and practical to operate.

[0007] In order to achieve the above technical objectives, the present invention adopts the following technical solutions:

[0008] A gravity-compressed gas energy storage system based on abandoned oil and gas wells, comprising a compressed gas energy storage device, an abandoned oil and gas well, and a gravity energy storage device;

[0009] The compressed gas energy storage device comprises a compression device and a high-pressure container connected in sequence; the high-pressure container is connected to the top of the wellbore of the abandoned oil and gas well through a pipeline;

[0010] A piston is installed in the wellbore of the abandoned oil and gas well, and lubrication and sealing are maintained between the piston and the wellbore; gas is above the piston and water is below the piston;

[0011] The gravity energy storage device includes a ground water storage tank, a reversible pump-turbine, a generator set, an injection pipe and a return pipe; the bottom of the abandoned oil and gas well is connected to the injection pipe and the return pipe respectively through water pipes; the injection pipe and the return pipe are both connected to the reversible pump-turbine; the reversible pump-turbine is connected to the ground water storage tank through a water pipe, and at the same time, the reversible pump-turbine is drivingly connected to the generator set.

[0012] Furthermore, a water injection pipe valve is provided on the water injection pipe, and a water return pipe valve is provided on the water return pipe.

[0013] Furthermore, the abandoned oil and gas wells are vertical well sections with a well depth of 1000-3000 meters.

[0014] Furthermore, above the abandoned oil and gas well is an abandoned oil and gas well platform, the compression device is connected to the high-pressure container through a pipeline and placed on the abandoned oil and gas well platform; the high-pressure container is connected to the top of the wellbore of the abandoned oil and gas well through a pipeline.

[0015] Furthermore, the high-pressure container is sealed and connected to the top of the wellbore of the abandoned oil and gas well through a connecting pipe, a connecting pipe head and a blowout preventer.

[0016] Furthermore, a pressure gauge for detecting gas pressure is provided on the connecting pipe above the wellbore.

[0017] Furthermore, the working process of the system includes an energy storage phase and a power generation phase;

[0018] The energy storage stage is specifically as follows: starting the compression device to deliver high-pressure gas to the high-pressure container, so that the upper space of the wellbore of the abandoned oil and gas well connected to the high-pressure container is filled with gas; then, starting the reversible water pump turbine, opening the water injection pipe, injecting water from the ground water reservoir into the underground wellbore through the water injection pipe, lifting the piston to move upward, compressing the gas in the upper space of the abandoned oil and gas well, so that the gas pressure reaches the set value, closing the water injection pipe, and completing the energy storage process;

[0019] The power generation stage is specifically as follows: releasing the high-pressure gas in the high-pressure container and the upper space of the wellbore, pushing the water in the lower space of the abandoned oil and gas well downward through the air pressure and the gravity of the piston itself, opening the return pipe, and allowing the water to flow back to the ground water reservoir through the return pipe. In this process, the water flow drives the reversible water pump turbine to work, driving the generator set to generate electricity, completing the energy release process.

[0020] Furthermore, in the energy storage stage, the compression device is started by utilizing valley electricity and / or renewable energy for power generation; and the reversible pump turbine is started by utilizing valley electricity and / or renewable energy for power generation.

[0021] Furthermore, the new energy power generation includes solar energy, hydrogen energy, nuclear energy, biomass energy, chemical energy, wind energy, ocean energy and geothermal energy.

[0022] At the same time, the present invention also provides a gravity-compressed gas energy storage method based on abandoned oil and gas wells, which is implemented by using any of the above energy storage systems, and the method comprises the following steps:

[0023] Step S1: pre-compression of gas; using valley electricity and / or new energy to generate electricity, starting the compression device to deliver high-pressure gas to the high-pressure container and the upper space of the wellbore, so that the gas storage space between the piston and the high-pressure container has an initial volume V1 and an initial pressure P1;

[0024] Step S2: gas compression energy storage; using valley electricity and / or new energy to generate electricity, start the reversible pump turbine, open the water injection pipe valve, inject water from the ground reservoir into the underground wellbore through the water injection pipe, lift the piston upward, reduce the volume of the gas storage space between the wellbore and the high-pressure container to V2, and increase the gas pressure to the design pressure P2;

[0025] Step S3: The system releases energy to generate electricity; the high-pressure gas in the high-pressure container and the upper part of the wellbore is released, and the water in the lower space of the abandoned oil and gas well is pushed downward with the help of the gravity of the piston itself, and the return pipe is opened to allow the water to flow back to the ground reservoir through the return pipe. In this process, the water flow drives the reversible water pump turbine to work, driving the generator set to generate electricity, completing the energy release process.

[0026] Compared with the prior art, the beneficial effects of the present invention are:

[0027] (1) The gravity-compressed gas energy storage system and method based on abandoned oil and gas wells provided by the present invention can utilize the underground space of a large number of abandoned oil and gas wells in oil and gas fields to build gravity energy storage and compressed air energy storage devices, integrating gravity energy storage and compressed air energy storage together for utilization, which can fully utilize the deep space of a large number of abandoned oil and gas wells and save the investment in building high platforms on the ground, and can also take into account the large potential energy difference required for gravity energy storage and the large high-pressure storage container required for compressed air storage, fully saving and integrating resources and improving energy utilization;

[0028] (2) The gravity-compressed gas energy storage system and method based on abandoned oil and gas wells provided by the present invention can utilize a large number of abandoned oil and gas wells in oil and gas fields for gravity energy storage, fully utilize the well depth to store the potential energy of heavy objects, and save the investment in building a high platform on the ground;

[0029] (3) The present invention provides a gravity-compressed gas energy storage system and method based on abandoned oil and gas wells, which utilizes the wellbore space to store compressed air energy without the need to build a large-capacity pressure vessel, and can achieve large-scale air energy storage;

[0030] (4) The present invention provides a gravity-compressed gas energy storage system and method based on abandoned oil and gas wells, which transfers potential energy through water energy and converts energy between electrical energy and gas compression potential energy through compressed air. The gas compression potential energy is only related to the gas volume and gas pressure, has few influencing factors, is highly controllable, and has the advantages of large energy storage, simple and reliable operation, and strong practicality. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A schematic diagram of the structure of the energy storage process of the energy storage system in an embodiment of the present invention;

[0032] Figure 2A schematic diagram of the structure of the power generation process of the energy storage system in an embodiment of the present invention;

[0033] Explanation of the markings in the figure: 1-compression device; 2-high-pressure container; 3-abandoned oil and gas well; 4-piston; 5-reversible pump-turbine; 6-generator set; 7-ground water storage tank; 8-injection pipe valve; 9-return pipe valve; 10-injection pipe; 11-return pipe. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] In the description of the present invention, it is necessary to understand that the terms "coaxial", "bottom", "one end", "top", "middle", "the other end", "upper", "one side", "top", "inside", "front", "center", "both ends" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0036] In the present invention, unless otherwise clearly stipulated and limited, the terms such as "installation", "setting", "connection", "fixation" and "screw-on" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal connection of two elements or the interaction relationship between two elements. Unless otherwise clearly defined, ordinary technicians in this field can understand the specific meanings of the above terms in the present invention according to the specific circumstances.

[0037] Example 1

[0038] Combination Figure 1-2 As shown, an embodiment of the present invention provides a gravity-compressed gas energy storage system based on abandoned oil and gas wells, including a compressed gas energy storage device, an abandoned oil and gas well 3 and a gravity energy storage device.

[0039] Among them, the compressed gas energy storage device includes a compression device 1 and a high-pressure container 2, and the gravity energy storage device includes a ground water reservoir 7, a reversible pump turbine 5, a generator set 6, an injection pipe valve 8, a return pipe valve 9, an injection pipe 10 and a return pipe 11.

[0040] Above the abandoned oil and gas well 3 is an abandoned oil and gas well platform. The compression device 1 is connected to the high-pressure container 2 through a pipeline and is placed on the abandoned oil and gas well platform. The high-pressure container 2 is sealed and connected to the top of the wellbore of the abandoned oil and gas well 3 through a connecting pipeline, a connecting pipe head and a blowout preventer, etc. A pressure gauge (not shown) for detecting gas pressure is provided on the connecting pipeline above the wellbore.

[0041] The abandoned oil and gas well 3 can freely select a vertical well section and ensure a sufficient depth, such as a well depth of 1000-3000 meters; a piston 4 is installed in the wellbore of the abandoned oil and gas well 3, and lubrication and sealing are maintained between the piston 4 and the wellbore of the abandoned oil and gas well 3; there is gas above the piston 4 and water below it.

[0042] The bottom of the abandoned oil and gas well 3 is connected to the injection pipe 10 and the return pipe 11 through water pipes; the injection pipe 10 and the return pipe 11 are both connected to the reversible pump turbine 5; the reversible pump turbine 5 is connected to the ground water reservoir 7 through a water pipe, and at the same time, the reversible pump turbine 5 is driven and connected to the generator set 6.

[0043] In addition, a water injection pipe valve 8 is provided on the water injection pipe 10 , and a water return pipe valve 9 is provided on the water return pipe 11 .

[0044] The working method of the energy storage system of the embodiment of the present invention is as follows:

[0045] (1) Energy storage stage: Figure 1 As shown, valley electricity and / or new energy are used to generate electricity, and the compression device 1 is started to deliver high-pressure gas to the high-pressure container 2, so that the upper space of the wellbore of the abandoned oil and gas well 3 connected to the high-pressure container 2 is filled with gas; at the same time, valley electricity and / or new energy are used to generate electricity, and the reversible pump turbine 5 is started to work, and the water injection pipe valve 8 is opened, and the water in the ground water reservoir 7 is injected into the underground wellbore through the water injection pipe 10, and the lifting piston 4 moves upward, so that the volume between the wellbore and the high-pressure container 2 is reduced, and the gas in the upper space of the abandoned oil and gas well 3 is compressed, so that the gas pressure reaches the set value, and the water injection pipe valve 8 is closed, and the energy storage process is completed;

[0046] (2) Power generation stage: Figure 2 As shown, the high-pressure gas in the high-pressure container 2 and the upper space of the wellbore is released, and the water in the lower space of the abandoned oil and gas well 3 is pushed downward by the air pressure and the gravity of the piston 4 itself, and the return pipe valve 9 is opened to allow the water to flow back to the ground water reservoir 7 through the return pipe 11. In this process, the water flow drives the reversible water pump turbine 5 to work, driving the generator set 6 to generate electricity, completing the energy release process.

[0047] Example 2

[0048] The embodiment of the present invention provides a gravity-compressed gas energy storage method based on abandoned oil and gas wells, which is implemented using the energy storage system in Example 1. The method includes the following steps:

[0049] Step S1: Gas pre-compression

[0050] Using valley electricity and / or new energy to generate electricity, the compression device 1 is started to deliver high-pressure gas to the high-pressure container 2, so that the gas storage space between the piston 4 and the high-pressure container 2 has an initial volume V1 and an initial pressure P1;

[0051] Step S2: Gas compression energy storage

[0052] Using valley electricity and / or new energy to generate electricity, the reversible pump turbine 5 is started, the water injection pipe valve 8 is opened, and the water in the ground water reservoir 7 is injected into the underground wellbore through the water injection pipe 10, so that the piston 4 moves upward, and the volume of the gas storage space between the wellbore and the high-pressure container 2 is reduced to V2, so that the pressure of the gas storage space is further increased to the design pressure P2, so as to maximize the storage capacity of the system;

[0053] Step S3: The system releases energy to generate electricity

[0054] The high-pressure gas in the high-pressure container 2 and the upper part of the wellbore is released, and the water in the lower space of the abandoned oil and gas well 3 is pushed downward by the gravity of the piston 4 itself, and the return pipe valve 9 is opened to allow the water to flow back to the ground water reservoir 7 through the return pipe 11. In this process, the water flow drives the reversible pump turbine 5 to work, driving the generator set 6 to generate electricity, completing the energy release process.

[0055] The above description is only an embodiment of the present invention and is not intended to limit the present invention. Any modification, equivalent replacement and improvement made within the application scope of the present invention shall be included in the protection scope of the present invention.

Claims

1. A gravity-compressed gas energy storage system based on abandoned oil and gas wells, characterized in that: Includes compressed gas energy storage devices, abandoned oil and gas wells, and gravity energy storage devices; The compressed gas energy storage device comprises a compression device and a high-pressure container connected in sequence; the high-pressure container is connected to the top of the wellbore of the abandoned oil and gas well through a pipeline; A piston is installed in the wellbore of the abandoned oil and gas well, and lubrication and sealing are maintained between the piston and the wellbore; gas is above the piston and water is below the piston; The gravity energy storage device includes a ground water storage tank, a reversible pump-turbine, a generator set, an injection pipe and a return pipe; the bottom of the abandoned oil and gas well is connected to the injection pipe and the return pipe respectively through water pipes; the injection pipe and the return pipe are both connected to the reversible pump-turbine; the reversible pump-turbine is connected to the ground water storage tank through a water pipe, and at the same time, the reversible pump-turbine is drivingly connected to the generator set.

2. The system according to claim 1, characterized in that The water injection pipe is provided with a water injection pipe valve, and the water return pipe is provided with a water return pipe valve.

3. The system according to claim 1, characterized in that The abandoned oil and gas wells are vertical well sections with a well depth of 1000-3000 meters.

4. The system according to claim 1, characterized in that Above the abandoned oil and gas well is an abandoned oil and gas well platform. The compression device is connected to the high-pressure container through a pipeline and is placed on the abandoned oil and gas well platform; the high-pressure container is connected to the top of the wellbore of the abandoned oil and gas well through a pipeline.

5. The system according to claim 4, characterized in that The high-pressure container is sealed and connected to the top of the wellbore of the abandoned oil and gas well through a connecting pipeline, a connecting pipe head and a blowout preventer.

6. The system according to claim 5, characterized in that A pressure gauge for detecting gas pressure is arranged on the connecting pipe above the wellbore.

7. The system according to any one of claims 1 to 6, characterized in that: The working process of the system includes an energy storage phase and a power generation phase; The energy storage stage is specifically as follows: starting the compression device to deliver high-pressure gas to the high-pressure container, so that the upper space of the wellbore of the abandoned oil and gas well connected to the high-pressure container is filled with gas; then, starting the reversible water pump turbine, opening the water injection pipe, injecting water from the ground water reservoir into the underground wellbore through the water injection pipe, lifting the piston to move upward, compressing the gas in the upper space of the abandoned oil and gas well, so that the gas pressure reaches the set value, closing the water injection pipe, and completing the energy storage process; The power generation stage is specifically as follows: releasing the high-pressure gas in the high-pressure container and the upper space of the wellbore, pushing the water in the lower space of the abandoned oil and gas well downward through the air pressure and the gravity of the piston itself, opening the return pipe, and allowing the water to flow back to the ground water reservoir through the return pipe. In this process, the water flow drives the reversible water pump turbine to work, driving the generator set to generate electricity, completing the energy release process.

8. The system according to claim 7, characterized in that In the energy storage stage, the compression device is started by utilizing valley electricity and / or renewable energy for power generation; the reversible pump turbine is started by utilizing valley electricity and / or renewable energy for power generation.

9. The system according to claim 8, characterized in that The new energy power generation includes solar energy, hydrogen energy, nuclear energy, biomass energy, chemical energy, wind energy, ocean energy and geothermal energy.

10. A gravity-compressed gas energy storage method based on abandoned oil and gas wells, implemented by using the energy storage system according to any one of claims 1 to 9, characterized in that: The method comprises the following steps: Step S1: pre-compression of gas; using valley electricity and / or new energy to generate electricity, starting the compression device to deliver high-pressure gas to the high-pressure container and the upper space of the wellbore, so that the gas storage space between the piston and the high-pressure container has an initial volume V1 and an initial pressure P1; Step S2: gas compression energy storage; using valley electricity and / or new energy to generate electricity, start the reversible pump turbine, open the water injection pipe valve, inject water from the ground reservoir into the underground wellbore through the water injection pipe, lift the piston upward, reduce the volume of the gas storage space between the wellbore and the high-pressure container to V2, and increase the gas pressure to the design pressure P2; Step S3: The system releases energy to generate electricity; the high-pressure gas in the high-pressure container and the upper part of the wellbore is released, and the water in the lower space of the abandoned oil and gas well is pushed downward with the help of the gravity of the piston itself, and the return pipe is opened to allow the water to flow back to the ground reservoir through the return pipe. In this process, the water flow drives the reversible water pump turbine to work, driving the generator set to generate electricity, completing the energy release process.

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