Energy storage system coupled with thickened oil steam drive exploitation and operation method of energy storage system

Abstract

The invention relates to the technical field of environment and energy systems, in particular to an energy storage system coupled with thickened oil steam drive exploitation and an operation method of the energy storage system. The system comprises a thickened oil recovery device, an energy storage device, an energy release device and a heat circulation device, and the thickened oil recovery device, the energy storage device and the energy release device are sequentially connected to form a circulation loop; the heat circulation device is used for absorbing heat released by the energy storage device and further used for transmitting the absorbed heat released by the energy storage device to the energy release device and the thickened oil recovery device. The system can flexibly adjust the steam temperature and pressure and the carbon dioxide temperature and pressure, the thickened oil is exploited through carbon dioxide assisted steam flooding, the requirement of steam flooding for hot steam is lowered, the crude oil recovery rate is increased, and the energy consumption in the whole thickened oil exploitation process is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of environment and energy systems, and in particular to an energy storage system coupled with heavy oil steam drive production and an operation method thereof. Background Art

[0002] The commonly used heavy oil recovery methods include steam stimulation, steam flooding, steam-assisted gravity drainage technology, fire flooding technology, carbon dioxide flooding, chemical flooding, etc. The basic principle of steam flooding is to inject steam into the formation, one well injects, and another well produces and recovers heavy oil. However, there are some difficulties that have not yet been overcome in steam flooding, including steam overburden, crossflow and viscous fingering. For this, non-hydrocarbon gases such as carbon dioxide can be used to assist steam displacement, which can improve these defects while saving a lot of hot steam.

[0003] Carbon dioxide energy storage technology is a gas-liquid interconversion and two-state synergy energy storage technology that is independent of geological conditions, has low pressure and temperature levels, high reliability and low cost. The basic principle is to use excess electricity to compress carbon dioxide gas at normal temperature and pressure into liquid during the low electricity consumption period, and store the heat energy generated during the compression process; during the peak electricity consumption period, the stored heat energy is used to heat the liquid carbon dioxide to gaseous state to drive the turbine to generate electricity.

[0004] In the existing technology, steam-driven heavy oil production has problems such as high energy consumption, steam overburden, crossflow and viscous fingering. Therefore, a method of energy storage system coupled with heavy oil steam-driven production is proposed, which combines carbon dioxide gas to assist steam displacement. While improving these problems, a large amount of hot steam is saved. Summary of the invention

[0005] In order to solve the above problems, the present invention provides an energy storage system coupled with heavy oil steam flooding and an operation method thereof. The present invention provides the following technical solutions:

[0006] An energy storage system coupled with heavy oil steam drive production, the system comprises a heavy oil production device, an energy storage device, an energy release device and a heat circulation device, wherein:

[0007] The heavy oil production device, the energy storage device, and the energy release device are connected in sequence to form a circulation loop;

[0008] The heat circulation device is used to absorb the heat released by the energy storage device, and is also used to transfer the absorbed heat released by the energy storage device to the energy release device and the heavy oil production device.

[0009] Furthermore, the heavy oil production device includes a production unit, a mixture separation unit, an oil storage unit and a second steam heater, wherein:

[0010] The second steam heater is used to heat the mining unit;

[0011] The outlet of the production unit is connected to the inlet of the mixture separation unit, the first outlet of the mixture separation unit is connected to the inlet of the oil storage unit, and the second outlet of the mixture separation unit is connected to the energy storage device.

[0012] Furthermore, the energy storage device includes a multi-stage compressor, a plurality of coolers, a gas-liquid separator, a first throttle valve and a high-pressure working fluid storage unit, wherein:

[0013] Multiple compressors are connected in series, and a cooler is provided at the outlet of each compressor.

[0014] The inlet of the first-stage compressor is connected to the second outlet of the mixture separation unit and the low-pressure working fluid storage unit. A gas-liquid separator is arranged in front of the inlet of the last-stage compressor. The outlet of the last-stage compressor is connected to the inlet of the first throttle valve through the heat exchange medium side of the corresponding cooler, and the outlet of the first throttle valve is connected to the inlet of the high-pressure working fluid storage unit.

[0015] Furthermore, the energy storage device includes a first compressor, a second compressor, a first cooler, a second cooler, a gas-liquid separator, a first throttle valve and a high-pressure working fluid storage unit, wherein:

[0016] The outlet of the first compressor is connected to the inlet of the gas-liquid separator through the heat exchange medium side of the first cooler.

[0017] The outlet of the gas-liquid separator is connected to the inlet of the second compressor.

[0018] The outlet of the second compressor is connected to the inlet of the first throttle valve through the heat exchange medium side of the second cooler, and the outlet of the first throttle valve is connected to the inlet of the high-pressure working medium storage unit.

[0019] Furthermore, the energy release device includes a plurality of heaters, a multi-stage turbine expander, a valve, a second throttle valve, a third throttle valve and a low-pressure working fluid storage unit, wherein:

[0020] The multi-stage turbine expanders are connected in series, and a heater is provided at the inlet of each stage of the turbine expander.

[0021] The first outlet of the heat exchange medium side of the heater corresponding to the last stage turbine expander is connected to the inlet of the last stage turbine expander, and the second outlet of the heat exchange medium side of the heater corresponding to the last stage turbine expander is connected to the heavy oil production device through the valve and the second throttle valve in sequence;

[0022] The outlet of the high-pressure working medium storage unit is connected to the inlet of the first-stage turbine expander through the heat exchange medium side of the heater, and the first outlet of the last-stage turbine expander is connected to the inlet of the low-pressure working medium storage unit through the third throttle valve;

[0023] The second outlet of the final stage turbine expander is connected to the heavy oil production device through a second throttle valve.

[0024] Furthermore, the energy release device includes a heater, a turbine expander, a valve, a second throttle valve, a third throttle valve and a low-pressure working fluid storage unit, wherein:

[0025] The outlet of the high-pressure working medium storage unit is connected to the inlet of the turbine expander through the first outlet on the heat exchange medium side of the heater, and the first outlet of the turbine expander is connected to the inlet of the low-pressure working medium storage unit through the third throttle valve;

[0026] The second outlet of the turbo expander is connected to the heavy oil production device through a second throttle valve;

[0027] The outlet of the high-pressure working medium storage unit is connected to the heavy oil production device through the second outlet on the heat exchange medium side of the heater, the valve and the second throttle valve.

[0028] Furthermore, the heat circulation device includes a low-temperature heat storage medium storage unit, a high-temperature heat storage medium storage unit and a first steam generator, wherein:

[0029] The outlet of the low-temperature heat storage medium storage unit is connected to the inlet of the high-temperature heat storage medium storage unit through the air side of the cooler.

[0030] The first outlet of the high temperature heat storage medium storage unit is connected to the inlet of the low temperature heat storage medium storage unit through the air side of the heater;

[0031] The second outlet of the high-temperature heat storage medium storage unit is connected to the heavy oil production device through the first steam generator.

[0032] Also provided is a method for operating the energy storage system coupled with heavy oil steam flooding as described above, the method comprising:

[0033] The carbon dioxide at normal temperature and pressure in the heavy oil production device and / or the energy release device enters the energy storage device;

[0034] The energy storage device compresses carbon dioxide at normal temperature and pressure into liquid state and stores it;

[0035] The heat circulation device obtains the heat generated by the energy storage device in the process of compressing carbon dioxide at normal temperature and pressure into a liquid state, and transfers the heat to the energy release device and / or the heavy oil recovery device;

[0036] The liquid carbon dioxide in the energy storage device enters the energy release device;

[0037] The energy release device utilizes the received heat to heat the received liquid carbon dioxide to obtain carbon dioxide in a predetermined state, and the carbon dioxide in the predetermined state enters the heavy oil production device and / or the energy release device.

[0038] Furthermore, the energy storage device compresses carbon dioxide at normal temperature and pressure into a liquid state and stores it, including:

[0039] The carbon dioxide at normal temperature and pressure is compressed by a multi-stage compressor and cooled by a corresponding cooler to obtain carbon dioxide in a first state;

[0040] The carbon dioxide in the first state is separated into water by a gas-liquid separator to obtain carbon dioxide in the second state;

[0041] The carbon dioxide in the second state is compressed by the final compressor and cooled by the cooler to obtain carbon dioxide at a predetermined temperature.

[0042] The carbon dioxide at a predetermined temperature is throttled and cooled by a first throttle valve to obtain liquid carbon dioxide;

[0043] Liquid carbon dioxide enters the high-pressure working fluid storage unit for storage.

[0044] Furthermore, the heat circulation device absorbs the heat generated in the process of the energy storage device compressing carbon dioxide at normal temperature and pressure into a liquid state, and transfers the heat to the energy release device, including:

[0045] The first low-temperature heat storage medium in the low-temperature heat storage medium storage unit passes through the air side of the cooler, absorbs the heat generated in the process of the energy storage device compressing carbon dioxide at normal temperature and pressure into liquid, and obtains high-temperature heat storage medium;

[0046] The high-temperature heat storage medium enters the high-temperature heat storage medium storage unit for storage;

[0047] After the high temperature heat storage medium in the high temperature heat storage medium storage unit releases heat through the air side of the heater, a second low temperature heat storage medium is obtained;

[0048] The second low-temperature heat storage medium enters the low-temperature heat storage medium storage unit for storage.

[0049] Furthermore, the energy release device utilizes the received heat to heat the received liquid carbon dioxide to obtain carbon dioxide in a predetermined state, and the carbon dioxide in the predetermined state enters the heavy oil production device and / or the energy release device, including:

[0050] Liquid carbon dioxide flows out from the high-pressure working fluid storage unit and is heated by the heat exchange medium side of the heater to obtain carbon dioxide in a predetermined state;

[0051] The carbon dioxide in a predetermined state enters the turbine expander through the first outlet on the heat exchange medium side of the heater to expand, drives the generator to generate electricity, and obtains the carbon dioxide in a second predetermined state;

[0052] The carbon dioxide in the second predetermined state is decompressed to normal pressure by the third throttle valve and then enters the low-pressure working fluid storage unit for storage; or,

[0053] The carbon dioxide in the second predetermined state is decompressed to a third predetermined state by the second throttle valve and then enters the heavy oil production device.

[0054] Furthermore, the method further comprises:

[0055] The carbon dioxide in a predetermined state sequentially passes through the second outlet on the heat exchange medium side of the heater, the valve, and the second throttle valve to enter the heavy oil production device.

[0056] Furthermore, the method further comprises:

[0057] The heat stored in the high-temperature heat storage medium storage unit assists the steam generated by the first steam generator, and the carbon dioxide in a predetermined state after expansion by the turbine expander enters the heavy oil production device through the second throttle valve and is injected into the production unit to obtain a heavy oil production mixture;

[0058] The heavy oil production mixture enters the mixture separation unit for separation, the separated crude oil enters the oil storage unit for storage, and the separated carbon dioxide enters the compressor.

[0059] Technical effects and advantages of the present invention:

[0060] The system of the present invention combines the carbon dioxide-assisted steam-driven heavy oil production technology with the compressed carbon dioxide energy storage technology, so that the carbon dioxide working fluid and heat are used in a gradient manner in the system, and the carbon dioxide and steam required for heavy oil production are used to generate electricity consumed in the off-peak electricity stage to reduce electricity costs. The system of the present invention can flexibly adjust the steam temperature and pressure and the carbon dioxide temperature and pressure, and produce heavy oil through carbon dioxide-assisted steam-driven production, thereby reducing the demand for hot steam for steam-driven production, improving crude oil recovery, and reducing energy consumption in the entire process of heavy oil production. Injecting carbon dioxide into heavy oil reservoirs can achieve greenhouse gas emission reduction, which has economic, environmental and social benefits. Combined with carbon dioxide energy storage technology, the power grid consumes electricity in the off-peak load stage and supplies electricity in the peak load stage, which can smooth out power grid load fluctuations, improve the overall load rate of the power system, improve the comprehensive utilization rate of power assets, and obtain electricity price difference benefits.

[0061] The compressor runs during off-peak hours, because of its high power, and although it only runs for a few hours, it can meet the heat consumption of heavy oil production steam and the consumption of pressurized carbon dioxide for 24 hours. During peak power consumption, the superheated carbon dioxide evaporated by the heat exchanger enters the turbine to expand and drive the generator to generate electricity and go online, supplying peak power and earning electricity price income.

[0062] Other features and advantages of the present invention will be described in the following description, and partly become obvious from the description, or be understood by implementing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] Figure 1 This is a diagram of an energy storage system coupled with heavy oil steam drive production provided in an embodiment of the present application.

[0064] In the figure: 1—low-pressure working fluid storage unit; 2-1—first motor; 2-2—second motor; 3-1—first compressor; 3-2—second compressor; 4-1—first cooler; 4-2—second cooler; 5—gas-liquid separator; 6—first throttle valve; 7—high-pressure working fluid storage unit; 8—low-temperature heat storage medium storage unit; 9—high-temperature heat storage medium storage unit; 10—heater; 11—turbine expander; 12—generator; 13—valve; 14—second throttle valve; 15—third throttle valve; 16—first steam generator; 17—second steam generator; 18—mixture separation unit; 19—oil storage unit. DETAILED DESCRIPTION

[0065] 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.

[0066] To solve the deficiencies of the prior art, the present invention discloses an energy storage system coupled with heavy oil steam drive production, such as Figure 1 As shown, the system includes a heavy oil production device, an energy storage device, an energy release device and a heat circulation device, wherein the heavy oil production device, the energy storage device and the energy release device are connected in sequence to form a circulation loop; the heat circulation device is used to absorb the heat released by the energy storage device, and is also used to transfer the absorbed heat released by the energy storage device to the energy release device and the heavy oil production device.

[0067] In a specific embodiment of the present invention, the heavy oil production device includes a production unit, a mixture separation unit 18, an oil storage unit 19 and a second steam heater 17, wherein:

[0068] The outlet of the production unit is connected to the inlet of the mixture separation unit 18, which is used to transport the heavy oil production mixture produced by the heavy oil production unit using high-temperature and high-pressure steam and pressurized carbon dioxide injected into the oil layer to the mixture separation unit 18, and separate the crude oil and carbon dioxide gas through the mixture separation unit 18.

[0069] The inlet of the extraction unit is connected to the second steam heater 17 and the first steam generator 16 to obtain high-temperature and high-pressure steam for oil extraction. The first outlet of the mixture separation unit 18 is connected to the inlet of the oil storage unit 19 to transport the separated crude oil to the oil storage unit 19; the second outlet of the mixture separation unit 18 is connected to the energy storage device to transport the separated atmospheric pressure carbon dioxide to the compressor of the energy storage device.

[0070] When more high-temperature steam is not needed in the heavy oil production process, the second steam generator 17 can be turned off to save costs. Only the first steam generator 16 delivers high-temperature and high-pressure steam to the production unit.

[0071] In a specific embodiment of the present invention, the energy storage device includes a multi-stage compressor, a plurality of coolers, a gas-liquid separator 5, a first throttle valve 6 and a high-pressure working fluid storage unit 7, wherein:

[0072] Multiple stages of compressors are connected in series in sequence, and a cooler is provided at the outlet of each stage of the compressor. The inlet of the first-stage compressor is connected to the second outlet of the mixture separation unit 18, and a gas-liquid separator 5 is provided in front of the inlet of the last-stage compressor. The outlet of the last-stage compressor is connected to the inlet of the first throttle valve 6 through the heat exchange medium side of the cooler, and the outlet of the first throttle valve 6 is connected to the inlet of the high-pressure working fluid storage unit 7.

[0073] Combination Figure 1 In the embodiment, the energy storage device provided by the present invention includes a first compressor 3-1, a second compressor 3-2, a first cooler 4-1, a second cooler 4-2, a gas-liquid separator, a throttle valve 6 and a high-pressure working fluid storage unit 7, wherein the first compressor 3-1 is connected to the first motor 2-1, and the second compressor 3-2 is connected to the second motor 2-2; the outlet of the first compressor 3-1 is connected to the inlet of the gas-liquid separator 5 through the heat exchange medium side of the first cooler 4-1, the outlet of the gas-liquid separator 5 is connected to the inlet of the second compressor 3-2, the outlet of the second compressor 3-2 is connected to the inlet of the first throttle valve 6 through the heat exchange medium side of the second cooler 4-2, and the outlet of the first throttle valve 6 is connected to the inlet of the high-pressure working fluid storage unit 7.

[0074] In a specific embodiment of the present invention, the energy release device includes multiple heaters, a multi-stage turbine expander, a second throttle valve 14, a third throttle valve 15 and a low-pressure working fluid storage unit 1, wherein the multi-stage turbine expanders are connected in series, a heater is provided at the inlet of each stage of the turbine expander, the outlet of the high-pressure working fluid storage unit 7 is connected to the inlet of the first-stage turbine expander through the heat exchange medium side of the heater, the first outlet of the last-stage turbine expander is connected to the inlet of the low-pressure working fluid storage unit 1 through the third throttle valve 15; the second outlet of the last-stage turbine expander is connected to the heavy oil production device through the second throttle valve 14.

[0075] Combination Figure 1 In the embodiment, the energy release device provided by the present invention includes a heater 10, a turbine expander 11, a second throttle valve 14, a third throttle valve 15 and a low-pressure working fluid storage unit 1, wherein the outlet of the high-pressure working fluid storage unit 7 is connected to the inlet of the turbine expander 11 through the first outlet on the heat exchange medium side of the heater 10, and the first outlet of the turbine expander 11 is connected to the inlet of the low-pressure working fluid storage unit 1 through the third throttle valve 15; the second outlet of the turbine expander 11 is connected to the heavy oil production device through the second throttle valve 14. The outlet of the high-pressure working fluid storage unit 7 is connected to the heavy oil production device through the second outlet on the heat exchange medium side of the heater 10, the valve 13 and the second throttle valve 14, to ensure that a sufficient amount of carbon dioxide can be provided for heavy oil production during the period when the turbine expander 11 is not in operation.

[0076] The compressor and the turbine expander in the energy storage device for compressing carbon dioxide and the energy release device for expanding carbon dioxide may include multiple stages, and heat exchangers are provided at the outlet of each compressor and the inlet of each turbine. The appropriate number of compressor and turbine expander stages is set according to the system design, the storage pressure of the high-pressure working fluid, the temperature of the heat storage medium, the steam temperature required for heavy oil production, and the carbon dioxide pressure. The pressurized carbon dioxide used for carbon dioxide-assisted steam drive to produce heavy oil can be the inter-stage exhaust of the turbine.

[0077] In a specific embodiment of the present invention, the heat circulation device includes a low-temperature heat storage medium storage unit 8, a high-temperature heat storage medium storage unit 9 and a first steam generator 16, wherein the outlet of the low-temperature heat storage medium storage unit 8 is connected to the inlet of the high-temperature heat storage medium storage unit 9 through the air side of the cooler, and the first outlet of the high-temperature heat storage medium storage unit 9 is connected to the inlet of the low-temperature heat storage medium storage unit 8 through the air side of the heater 10; the second outlet of the high-temperature heat storage medium storage unit 9 is connected to the first steam generator 16.

[0078] Combination Figure 1Exemplarily, the heat circulation device includes a low-temperature heat storage medium storage unit 8 and a high-temperature heat storage medium storage unit 9, wherein the outlet of the low-temperature heat storage medium storage unit 8 is connected to the inlet of the high-temperature heat storage medium storage unit 9 after passing through the air side of the first cooler 4-1 and / or the second cooler 4-2, and the first outlet of the high-temperature heat storage medium storage unit 9 is connected to the inlet of the low-temperature heat storage medium storage unit 8 through the air side of the heater 10; the second outlet of the high-temperature heat storage medium storage unit 9 is connected to the heavy oil production device through the first steam generator 16.

[0079] The first steam generator in the heat circulation device can adopt different forms. For example, if water is used as the heat storage medium of the heat exchanger after the compressor, high-temperature and high-pressure water vapor can be obtained by flash evaporation, and the low-temperature heat storage medium storage device needs to replenish the heat storage medium water during operation; if heat transfer oil is used as the heat storage medium of the heat exchanger after the compressor, high-temperature and high-pressure water vapor can be obtained by a heat exchange steam generator.

[0080] Energy storage devices, energy release devices, heat circulation devices and heavy oil production devices involve the heat balance of the operating medium and the amount of material balance. The system operating parameters can be adjusted according to different needs to achieve different operating requirements such as energy storage power generation, heat storage utilization, and carbon dioxide-assisted steam drive heavy oil production.

[0081] The present invention also provides an operation method of an energy storage system coupled with heavy oil steam drive production, the method comprising:

[0082] Step 1: The carbon dioxide at normal temperature and pressure in the heavy oil production device and / or the energy release device enters the energy storage device; wherein the carbon dioxide at normal temperature and pressure comes from the carbon dioxide at normal temperature and pressure obtained after separation by the mixture separation unit 18 in the heavy oil production device; or, the carbon dioxide at normal temperature and pressure comes from the carbon dioxide in the low-pressure working fluid storage unit 1 in the energy release device.

[0083] Step 2: The energy storage device compresses the carbon dioxide at normal temperature and pressure into a liquid state and stores it;

[0084] Step 3: The heat circulation device obtains the heat generated by the energy storage device in the process of compressing carbon dioxide at normal temperature and pressure into a liquid state, and transfers the heat to the energy release device and / or the heavy oil recovery device;

[0085] Step 4: The liquid carbon dioxide in the energy storage device enters the energy release device;

[0086] Step 5: The energy release device uses the received heat to heat the received liquid carbon dioxide to obtain carbon dioxide in a predetermined state, and the carbon dioxide in the predetermined state enters the heavy oil production device and / or the energy release device.

[0087] In a specific embodiment of the present invention, in step 2, the energy storage device compresses carbon dioxide at room temperature and pressure into a liquid state and stores it, including:

[0088] Step 201: The carbon dioxide at normal temperature and pressure is compressed by a multi-stage compressor to reach a high temperature and high pressure state, and then cooled by a corresponding cooler to obtain carbon dioxide in a first state;

[0089] Step 202: The carbon dioxide in the first state is separated from the water by the gas-liquid separator 5 to obtain the carbon dioxide in the second state;

[0090] Step 203: The carbon dioxide in the second state is compressed by a compressor and cooled by a cooler until carbon dioxide at a predetermined temperature is obtained.

[0091] Step 204: The carbon dioxide at a predetermined temperature is throttled and cooled and liquefied through the first throttle valve 6 to obtain liquid carbon dioxide;

[0092] Step 205: Liquid carbon dioxide enters the high-pressure working fluid storage unit 7 for storage.

[0093] The compressor in the energy storage device for compressing carbon dioxide is the main power-consuming equipment of the system of the present invention. The power and operating time can be reasonably set according to the heat and carbon dioxide requirements of the system of the present invention, so that the operating stage is at the low point of electricity prices, which significantly reduces the cost of heavy oil extraction.

[0094] In a specific embodiment of the present invention, in step 3, the circulation device obtains heat generated by the energy storage device in the process of compressing carbon dioxide at normal temperature and pressure into a liquid state, and transfers the heat to the energy release device, including:

[0095] Step 301: The first low-temperature heat storage medium in the storage unit 8 passes through the air side of the first cooler 4-1 and / or the second cooler 4-2, absorbs the heat generated in the process of the energy storage device compressing carbon dioxide at normal temperature and pressure into liquid, and obtains a high-temperature heat storage medium;

[0096] Step 302: the high temperature heat storage medium enters the high temperature heat storage medium storage unit 9 for storage;

[0097] Step 303: After the high-temperature heat storage medium in the high-temperature heat storage medium storage unit 9 releases heat through the air side of the heater, a second low-temperature heat storage medium is obtained;

[0098] Step 304: the second low-temperature heat storage medium enters the low-temperature heat storage medium storage unit 8 for storage.

[0099] The heat storage medium in the heat circulation device flows out from the low-temperature heat storage medium storage unit 8 , passes through the cooler to absorb heat, and is stored in the high-temperature heat storage medium storage unit 9 .

[0100] In a specific embodiment of the present invention, in step 4, the energy release device uses the received heat to heat the received liquid carbon dioxide to obtain carbon dioxide in a predetermined state, and the carbon dioxide in the predetermined state enters the heavy oil production device and / or the energy release device, including:

[0101] Step 401: Liquid carbon dioxide flows out from the high-pressure working fluid storage unit 7, is evaporated and superheated on the heat exchange medium side of the heater 10, and obtains carbon dioxide in a predetermined state, which is gaseous, 6MPa-7MPa, and 200°C-250°C.

[0102] Step 402: The carbon dioxide in a predetermined state is expanded by the turbine expander 11, driving the generator 12 to generate electricity;

[0103] Step 403: the predetermined state carbon dioxide after expansion by the turbine expander 11 is adjusted in pressure by the third throttle valve 15 and enters the low-pressure working medium storage unit 1 for storage; and / or,

[0104] Step 404: the carbon dioxide in a predetermined state after expansion by the turbine expander 11 enters the heavy oil production device through the second throttle valve 14.

[0105] In a specific embodiment of the present invention, the method further comprises: the heat stored in the high-temperature heat storage medium storage unit 9 assists the steam generated by the first steam generator 16, and the carbon dioxide in a predetermined state after expansion through the turbine 11 enters the heavy oil production device through the second throttle valve 14 and is injected into the production unit to obtain a heavy oil production mixture;

[0106] The heavy oil production mixture enters the mixture separation unit 18 for separation, the separated crude oil enters the oil storage unit 19 for storage, and the separated carbon dioxide enters the compressor of the heavy oil production mixture.

[0107] During the process, the heat storage medium in the high-temperature heat storage medium storage unit 9 flows out, flows into the heater 10 to heat the carbon dioxide, and then enters the low-temperature heat storage medium storage device 8. The turbine expander 11 in the energy release device for expanding carbon dioxide is a differential pressure turbine. By adjusting the pressure and temperature of the carbon dioxide at the inlet of the expander 11, the pressure and temperature of the carbon dioxide at the outlet of the turbine expander 11 can be adjusted, so that the carbon dioxide at the outlet of the turbine expander 11 can meet the auxiliary steam drive for heavy oil production. According to different needs, different levels of turbine expanders are set. When the turbine expander 11 outlet carbon dioxide is not needed to assist steam drive for heavy oil production, the carbon dioxide is further reheated and expanded to atmospheric pressure to enter the low-pressure working medium storage device 1 for storage and increase the power generation; when a large amount of carbon dioxide is needed to assist steam drive for heavy oil production, the valve 13 controls the liquid carbon dioxide to flow out of the high-pressure working medium storage unit 7, evaporate and overheat through the heat exchanger 10, and then directly enter the second throttle valve 14 without expansion through the turbine expander 11 to adjust the pressure and enter the carbon dioxide assisted steam drive for heavy oil production device.

[0108] It should be noted that the carbon dioxide stored in the low-pressure working fluid storage unit 1 is atmospheric carbon dioxide. The carbon dioxide used for heavy oil production has a certain pressure, and this pressure can be controlled according to the turbine adjustment. If more carbon dioxide is supplied to heavy oil production, the carbon dioxide will expand and reduce the pressure in the turbine, for example, the pressure may be reduced to 1MPa, and the turbine output is small. If less carbon dioxide is supplied to heavy oil production, the carbon dioxide will expand and reduce the pressure to atmospheric pressure 0.1MPa in the turbine expander 11 and enter the low-pressure working fluid storage unit 1 for storage, and the turbine output will be large to supply more peak electricity.

[0109] In the heat circulation device, the heat storage medium in the high-temperature heat storage medium storage unit 9 stores a large amount of high-temperature heat generated after compression by the compressor, part of which is used for evaporation and superheating of liquid carbon dioxide in the expansion carbon dioxide energy release device, and part of which is used for high-temperature steam generation in the carbon dioxide-assisted steam drive heavy oil production device.

[0110] In the heavy oil recovery device used for carbon dioxide-assisted steam flooding, high-temperature and high-pressure steam and pressurized carbon dioxide are injected into the oil layer to recover the heavy oil recovery mixture, and the crude oil and carbon dioxide gas are separated by the mixture separation unit 18. The carbon dioxide gas is used as one of the working fluid sources in the compressed carbon dioxide energy storage device.

[0111] The technical solution of the present invention will be further described below in conjunction with specific implementation methods.

[0112] In the compressed carbon dioxide energy storage device, the motor 2 uses off-peak electricity, abandoned wind and abandoned photovoltaic power to drive the compressor 3-1 to compress the carbon dioxide from the low-pressure working fluid storage unit 1 and the mixture separation unit 18, from normal temperature and pressure to a high-temperature and high-pressure state, and the temperature is reduced after passing through the cooler, and then the precipitated water is separated by the gas-liquid separator 5. According to the system design, the compression and heat exchange process can be performed again. The carbon dioxide at the outlet of the final compressor is throttled and cooled and liquefied by the first throttle valve 6, and the liquid carbon dioxide enters the high-pressure working fluid storage unit 7 for storage. The heat storage medium in the heat circulation device flows out from the low-temperature heat storage medium storage unit 8, absorbs heat through the cooler and is stored in the high-temperature heat storage medium storage unit 9. The compressor in the compressed carbon dioxide energy storage device is the main power-consuming equipment of the system of the present invention. The power and operating time can be reasonably set according to the heat and carbon dioxide requirements of the system of the invention, so that the operation stage is at the low electricity price stage, which significantly reduces the cost of heavy oil extraction. For example, local policy stipulates that the electricity price is low from midnight to four o'clock every day, and the compressor is designed to have a power of 20MW. Later, the electricity price is low during the period from midnight to eight o'clock every day, and the compressor is operated at a power of 10MW, always operating during the period of low electricity price. When the steam demand for steam drive in heavy oil production increases, on the one hand, the compressor operation time can be increased to increase the heat output and store it in the heat storage medium for steam generation. On the other hand, the turbine expander 11 can be adjusted to reduce the output. The turbine consumes less heat and can supply more heat for the first steam generator 16. The system compressor, turbine operating power, and operating time can be adjusted according to different operating requirements to match the demand for steam and pressurized carbon dioxide in heavy oil production.

[0113] In the expansion carbon dioxide energy release device, liquid carbon dioxide flows out from the high-pressure working fluid storage unit 7, evaporates and superheats through the heater 10, and then the high-temperature and high-pressure gaseous carbon dioxide expands through the turbine expander 11, driving the generator 12 to generate electricity. The expanded gaseous carbon dioxide leaves the turbine expander 11 and enters the third throttle valve 15 to adjust the pressure before entering the low-pressure working fluid storage unit 1 for storage or enters the second throttle valve 14 to adjust the pressure before entering the carbon dioxide assisted steam drive heavy oil production device. During the process, the heat storage medium in the high-temperature heat storage medium storage unit 9 flows out, flows into the heater 10 to heat the carbon dioxide, and then enters the low-temperature heat storage medium storage unit 8. In the expansion carbon dioxide energy release system, the turbine expander 11 is a differential pressure turbine. By adjusting the pressure and temperature of the carbon dioxide at the inlet of the turbine expander 11, the pressure and temperature of the carbon dioxide at the outlet of the turbine expander 11 can be adjusted, so that the carbon dioxide at the outlet of the turbine expander 11 can meet the auxiliary steam drive heavy oil production. According to different needs, turbines of different stages are set. When the turbine outlet carbon dioxide-assisted steam drive for heavy oil production is not needed, the carbon dioxide is further reheated and expanded to atmospheric pressure to enter the low-pressure working fluid storage unit 1 for storage and to increase the power generation capacity; when a large amount of carbon dioxide-assisted steam drive for heavy oil production is needed, liquid carbon dioxide flows out of the high-pressure working fluid storage unit 7 through the control of valve 13, is evaporated and superheated by the heater 10, and then directly enters the second throttle valve 14 through valve 13 to adjust the pressure without expanding through the turbine expander 11, and then enters the carbon dioxide-assisted steam drive system for heavy oil production.

[0114] In the heat recycling system, the heat storage medium in the high-temperature heat storage medium storage unit 9 stores a large amount of high-temperature heat generated by the compressor 3 after compression, part of which is used for evaporation and superheating of the liquid carbon dioxide heater 10 in the expansion carbon dioxide energy release device, and part of which is used for high-temperature steam generation in the first steam generator 16 in the carbon dioxide-assisted steam drive heavy oil recovery device. If more high-temperature steam is needed, the second steam generator 17 is used to generate high-temperature steam at the same time, which can be a natural gas boiler or an electric boiler.

[0115] In the carbon dioxide-assisted steam drive system for heavy oil production, the high-temperature and high-pressure steam generated by the first steam generator 16 and the pressurized carbon dioxide after the pressure is adjusted by the second throttle valve 14 are injected into the oil layer to produce a heavy oil production mixture. The crude oil and carbon dioxide gas are separated by the heavy oil production mixture separation unit 18. The carbon dioxide gas is used as one of the working fluid sources in the compressed carbon dioxide energy storage system, and the crude oil enters the production oil storage unit 19 for storage.

[0116] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An energy storage system coupled with heavy oil steam flooding, characterized in that: The system comprises a heavy oil production device, an energy storage device, an energy release device and a heat circulation device, wherein: The heavy oil production device, the energy storage device, and the energy release device are connected in sequence to form a circulation loop; The heat circulation device is used to absorb the heat released by the energy storage device, and is also used to transfer the absorbed heat released by the energy storage device to the energy release device and the heavy oil production device.

2. The energy storage system coupled with heavy oil steam flooding according to claim 1, characterized in that: The heavy oil production device comprises a production unit, a mixture separation unit (18), an oil storage unit (19) and a second steam heater (17), wherein: The second steam heater (17) is used to heat the mining unit; The outlet of the production unit is connected to the inlet of the mixture separation unit (18), the first outlet of the mixture separation unit (18) is connected to the inlet of the oil storage unit (19), and the second outlet of the mixture separation unit (18) is connected to the energy storage device.

3. The energy storage system coupled with heavy oil steam flooding according to claim 2, characterized in that: The energy storage device comprises a multi-stage compressor, a plurality of coolers, a gas-liquid separator (5), a first throttle valve (6) and a high-pressure working fluid storage unit (7), wherein: Multiple compressors are connected in series, and a cooler is provided at the outlet of each compressor. The inlet of the first-stage compressor is connected to the second outlet of the mixture separation unit (18) and the low-pressure working fluid storage unit (1), and a gas-liquid separator (5) is arranged before the inlet of the final-stage compressor. The outlet of the final-stage compressor is connected to the inlet of the first throttle valve (6) through the heat exchange medium side of the corresponding cooler, and the outlet of the first throttle valve (6) is connected to the inlet of the high-pressure working fluid storage unit (7).

4. The energy storage system coupled with heavy oil steam flooding according to claim 1, characterized in that: The energy storage device comprises a first compressor (3-1), a second compressor (3-2), a first cooler (4-1), a second cooler (4-2), a gas-liquid separator (5), a first throttle valve (6) and a high-pressure working fluid storage unit (7), wherein: The outlet of the first compressor (3-1) is connected to the inlet of the gas-liquid separator (5) via the heat exchange medium side of the first cooler (4-1). The outlet of the gas-liquid separator (5) is connected to the inlet of the second compressor (3-2). The outlet of the second compressor (3-2) is connected to the inlet of the first throttle valve (6) through the heat exchange medium side of the second cooler (4-2), and the outlet of the first throttle valve (6) is connected to the inlet of the high-pressure working fluid storage unit (7).

5. The energy storage system coupled with heavy oil steam flooding according to any one of claims 1 to 4, characterized in that: The energy release device comprises a plurality of heaters, a multi-stage turbine expander, a valve (13), a second throttle valve (14), a third throttle valve (15) and a low-pressure working medium storage unit (1), wherein: The multi-stage turbine expanders are connected in series, and a heater is provided at the inlet of each stage of the turbine expander. The first outlet on the heat exchange medium side of the heater corresponding to the final stage turbine expander is connected to the inlet of the final stage turbine expander, and the second outlet on the heat exchange medium side of the heater corresponding to the final stage turbine expander is connected to the heavy oil production device through the valve (13) and the second throttle valve (14) in sequence; The outlet of the high-pressure working medium storage unit (7) is connected to the inlet of the first-stage turbine expander through the heat exchange medium side of the heater, and the first outlet of the last-stage turbine expander is connected to the inlet of the low-pressure working medium storage unit (1) through the third throttle valve (15); The second outlet of the final stage turbine expander is connected to the heavy oil production device through a second throttle valve (14).

6. The energy storage system coupled with heavy oil steam flooding according to any one of claims 1 to 4, characterized in that: The energy release device comprises a heater (10), a turbine expander (11), a valve (13), a second throttle valve (14), a third throttle valve (15) and a low-pressure working medium storage unit (1), wherein: The outlet of the high-pressure working medium storage unit (7) is connected to the inlet of the turbine expander (11) through the first outlet on the heat exchange medium side of the heater (10), and the first outlet of the turbine expander (11) is connected to the inlet of the low-pressure working medium storage unit (1) through the third throttle valve (15); The second outlet of the turbo expander (11) is connected to the heavy oil production device through a second throttle valve (14); The outlet of the high-pressure working fluid storage unit (7) is connected to the heavy oil production device through the second outlet on the heat exchange medium side of the heater (10), the valve (13) and the second throttle valve (14).

7. The energy storage system coupled with heavy oil steam flooding according to claim 1, characterized in that: The heat circulation device comprises a low-temperature heat storage medium storage unit (8), a high-temperature heat storage medium storage unit (9) and a first steam generator (16), wherein: The outlet of the low-temperature heat storage medium storage unit (8) is connected to the inlet of the high-temperature heat storage medium storage unit (9) through the air side of the cooler. The first outlet of the high-temperature heat storage medium storage unit (9) is connected to the inlet of the low-temperature heat storage medium storage unit (8) through the air side of the heater (10); The second outlet of the high-temperature heat storage medium storage unit (9) is connected to the heavy oil production device via the first steam generator (16).

8. The method for operating an energy storage system coupled with heavy oil steam flooding according to any one of claims 1 to 7, characterized in that: The method comprises, The carbon dioxide at normal temperature and pressure in the heavy oil production device and / or the energy release device enters the energy storage device; The energy storage device compresses carbon dioxide at normal temperature and pressure into liquid state and stores it; The heat circulation device obtains the heat generated by the energy storage device in the process of compressing carbon dioxide at normal temperature and pressure into a liquid state, and transfers the heat to the energy release device and / or the heavy oil recovery device; The liquid carbon dioxide in the energy storage device enters the energy release device; The energy release device utilizes the received heat to heat the received liquid carbon dioxide to obtain carbon dioxide in a predetermined state, and the carbon dioxide in the predetermined state enters the heavy oil production device and / or the energy release device.

9. The operating method according to claim 8, characterized in that: The energy storage device compresses carbon dioxide at normal temperature and pressure into a liquid state and stores the carbon dioxide, including: The carbon dioxide at normal temperature and pressure is compressed by a multi-stage compressor and cooled by a corresponding cooler to obtain carbon dioxide in a first state; The carbon dioxide in the first state is separated into water by a gas-liquid separator (5) to obtain carbon dioxide in the second state; The carbon dioxide in the second state is compressed by the final compressor and cooled by the cooler to obtain carbon dioxide at a predetermined temperature. The carbon dioxide at a predetermined temperature is throttled and cooled by a first throttle valve (6) to obtain liquid carbon dioxide; Liquid carbon dioxide enters the high-pressure working fluid storage unit (7) for storage.

10. The operating method according to claim 8, characterized in that: The heat circulation device absorbs the heat generated by the energy storage device in the process of compressing carbon dioxide at normal temperature and pressure into a liquid state, and transfers the heat to the energy release device, including: The first low-temperature heat storage medium in the low-temperature heat storage medium storage unit (8) passes through the air side of the cooler, absorbs the heat generated in the process of the energy storage device compressing carbon dioxide at normal temperature and pressure into liquid, and obtains high-temperature heat storage medium; The high-temperature heat storage medium enters a high-temperature heat storage medium storage unit (9) for storage; After the high-temperature heat storage medium in the high-temperature heat storage medium storage unit (9) releases heat through the air side of the heater, a second low-temperature heat storage medium is obtained; The second low-temperature heat storage medium enters the low-temperature heat storage medium storage unit (8) for storage.

11. The operating method according to claim 8, characterized in that: The energy release device uses the received heat to heat the received liquid carbon dioxide to obtain carbon dioxide in a predetermined state, and the carbon dioxide in the predetermined state enters the heavy oil production device and / or the energy release device, including: Liquid carbon dioxide flows out from the high-pressure working fluid storage unit (7) and is heated by the heat exchange medium side of the heater (10) to obtain carbon dioxide in a predetermined state; The carbon dioxide in a predetermined state enters a turbine expander (11) through a first outlet on the heat exchange medium side of the heater (10) to expand, drives a generator (12) to generate electricity, and obtains carbon dioxide in a second predetermined state; The carbon dioxide in the second predetermined state is decompressed to a normal pressure state through a third throttle valve (15) and then enters a low-pressure working fluid storage unit (1) for storage; or, The carbon dioxide in the second predetermined state is decompressed to a third predetermined state through a second throttle valve (14) and then enters the heavy oil production device.

12. The operating method according to claim 11, characterized in that: The method further comprises: The carbon dioxide in a predetermined state enters the heavy oil production device through the second outlet on the heat exchange medium side of the heater (10), the valve (13), and the second throttle valve (14) in sequence.

13. The operating method according to claim 11 or 12, characterized in that: The method further comprises: The heat stored in the high-temperature heat storage medium storage unit (9) assists the steam generated by the first steam generator (16), and the carbon dioxide in a predetermined state after expansion through the turbine expander (11) enters the heavy oil production device through the second throttle valve (14) and is injected into the production unit to obtain a heavy oil production mixture; The heavy oil production mixture enters the mixture separation unit (18) for separation, the separated crude oil enters the oil storage unit (19) for storage, and the separated carbon dioxide enters the compressor.

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