A petroleum and natural gas co-storage type salt cavern storage and method of operating the same

Abstract

The application discloses a kind of petroleum and natural gas co-storage type salt cave reservoir and its operating method, it is related to energy storage technical field, reservoir includes: oil storage salt cave, gas storage salt cave and bottom passage, the top of bottom passage two ends respectively with the bottom of oil storage salt cave and the bottom of gas storage salt cave communication;Petroleum injection-production well, the bottom of petroleum injection-production well with the top of oil storage salt cave communication;Natural gas injection-production well, the bottom of natural gas injection-production well with the top of gas storage salt cave communication;Brine injection-production well, the bottom of brine injection-production well with the top of bottom passage middle end communication;The petroleum of oil storage salt cave is separated with the natural gas of gas storage salt cave by brine of bottom passage, the density of brine is higher than petroleum and natural gas, and brine and petroleum and natural gas are not soluble.This application proposes to separate petroleum and natural gas by brine, realize petroleum and natural gas co-storage.

Description

Technical Field

[0001] This invention relates to the field of energy storage technology, and in particular to a salt cavern storage facility for both oil and natural gas and its operation method. Background Technology

[0002] Natural gas and oil are two important fossil fuels, and their effective storage is of great significance to social and economic development. Underground salt caverns, as excellent sites for storing oil or natural gas, can achieve underground storage of both. Currently, salt cavern storage facilities use only one storage medium, allowing for the separate storage of either liquefied oil or gaseous natural gas, and cannot achieve mixed storage of the two. Mixed storage of oil and natural gas in salt caverns would result in natural gas being contaminated by petroleum volatiles, thus reducing the utilization efficiency of natural gas. In conclusion, salt caverns use only one storage medium and cannot achieve the mixed storage of gaseous natural gas and liquefied oil; therefore, establishing mixed storage facilities for natural gas and oil in salt caverns is of great significance for regional energy diversity and development. Summary of the Invention

[0003] The purpose of this invention is to provide a salt cavern storage facility for co-storing oil and natural gas and its operation method, proposing to achieve co-storage of oil and natural gas by separating oil and natural gas with brine.

[0004] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0005] One aspect of this invention provides a co-storage salt cavern for oil and natural gas, comprising: an oil storage salt cavern, a gas storage salt cavern, and a bottom channel. The top two ends of the bottom channel are respectively connected to the bottom of the oil storage salt cavern and the bottom of the gas storage salt cavern; an oil injection-production well, the bottom of which is connected to the top of the oil storage salt cavern, and the top of which is connected to an external oil pipeline via the ground; a natural gas injection-production well, the bottom of which is connected to the top of the gas storage salt cavern, and the top of which is connected to an external natural gas pipeline via the ground; and a brine injection-discharge well, the bottom of which is connected to the middle of the top of the bottom channel, and the top of which is connected to an external brine pipeline via the ground. The oil in the oil storage salt cavern and the natural gas in the gas storage salt cavern are separated by brine in the bottom channel. The brine has a higher density than both the oil and natural gas, and the brine is immiscible with both the oil and natural gas.

[0006] In some embodiments, the external oil pipeline includes a production valve, an injection valve, and an injection pump. The top of the oil injection-production well is connected to one end of the production valve and one end of the injection pump via an oil pipeline. The other end of the injection pump is connected to one end of the injection valve. The other end of the injection valve is used to inject oil into the oil storage salt cavern, and the other end of the production valve is used to extract oil from the oil storage salt cavern. The external oil pipeline also includes an oil buffer device. The first end of the oil buffer device is connected to the other end of the production valve, the second end of the oil buffer device is connected to the other end of the injection valve, and the third end of the oil buffer device is connected to a pipeline for input or output. The external oil pipeline also includes a main oil switch, and the third end of the oil buffer device is connected to the main oil switch.

[0007] In some embodiments, the external brine pipeline includes a brine discharge valve, a brine injection valve, and a brine injection pump. The top of the brine injection / discharge well is connected to one end of the brine discharge valve and one end of the brine injection pump via a brine delivery pipeline. The other end of the brine injection pump is connected to one end of the brine injection valve. The other end of the brine injection valve is used to inject brine into the bottom channel, and the other end of the brine discharge valve is used to discharge brine from the bottom channel. The external brine pipeline also includes a brine tank. The first end of the brine tank is connected to the other end of the brine discharge valve, the second end of the brine tank is connected to the other end of the brine injection valve, and the third end of the brine tank is connected to a pipeline for input or output. The external brine pipeline also includes a brine master switch, and the third end of the brine tank is connected to the brine master switch.

[0008] In some embodiments, the natural gas pipeline includes a gas extraction valve, a gas injection valve, and a natural gas compressor. The top of the natural gas injection-production well is connected to one end of the gas extraction valve and one end of the natural gas compressor via a gas transmission pipeline. The other end of the natural gas compressor is connected to one end of the gas injection valve. The other end of the gas injection valve is used to inject natural gas into the gas storage salt cavern, and the other end of the gas extraction valve is used to extract natural gas from the gas storage salt cavern. The natural gas pipeline also includes a natural gas main switch, and the other ends of the gas injection valve and the gas extraction valve are both connected to the natural gas main switch.

[0009] In some embodiments, the storage tank is provided with a minimum oil-brine interface between petroleum and brine, and a minimum gas-brine interface between natural gas and brine. The oil-brine interface between petroleum and brine is not lower than the minimum oil-brine interface, and the gas-brine interface between natural gas and brine is not lower than the minimum gas-brine interface. Both the minimum oil-brine interface and the minimum gas-brine interface are higher than the bottom channel, so that the storage tank can separate the petroleum and natural gas through the brine in the bottom channel. The oil-salt storage pit, the gas-salt storage pit, and the bottom channel are all provided with sediment.

[0010] One aspect of this invention provides an operation method for a co-storage salt cavern reservoir for oil and natural gas. The operation method includes: injecting brine into a bottom channel through brine injection and discharge wells; stopping brine injection when the bottom channel, oil-storage salt cavern, gas-storage salt cavern, oil injection-production well, natural gas injection-production well, and brine injection and discharge well are full; injecting oil into the oil-storage salt cavern through the oil injection-production well and discharging brine; stopping oil injection when the oil-brine interface reaches the minimum oil-brine interface; injecting natural gas into the gas-storage salt cavern through the natural gas injection-production well and discharging brine; stopping natural gas injection when the gas-brine interface reaches the minimum gas-brine interface; and injecting brine into the bottom channel through the brine injection and discharge wells when gas or oil needs to be extracted, thereby discharging natural gas or oil.

[0011] In some embodiments, when oil is injected into the oil-salt storage cavern through the oil injection-production well and brine is discharged, the oil injection is stopped when the oil-brine interface reaches the lowest oil-brine interface. The method includes: closing the gas injection valve, gas production valve, natural gas compressor, oil production valve, brine injection valve and brine injection pump; opening the oil injection valve, oil injection pump, oil main switch, brine main switch and brine discharge valve; the oil enters the oil buffer device through the oil main switch, and then enters the oil-salt storage cavern through the oil injection valve, oil injection pump and oil injection-production well.

[0012] In some embodiments, natural gas is injected into the gas storage salt cavern through the natural gas injection-production well, and brine is discharged. When the gas-brine interface between natural gas and brine reaches the lowest gas-brine interface, the injection of natural gas is stopped. The method includes: closing the oil production valve, oil injection valve, oil injection pump, brine injection valve, brine injection pump, and gas production valve; opening the brine discharge valve, brine main switch, natural gas main switch, gas injection valve, and natural gas compressor; and natural gas entering the gas storage salt cavern through the natural gas main switch, gas injection valve, natural gas compressor, and natural gas injection-production well.

[0013] In some embodiments, when gas or oil needs to be extracted, brine is injected into the bottom channel through the brine injection and discharge well, and natural gas or oil is discharged through the injected brine. The method includes: closing the gas injection valve, gas production valve, natural gas compressor, oil injection valve, oil injection pump and brine discharge valve; opening the main oil switch, oil production valve, brine injection valve and brine injection pump; brine entering the bottom channel through the brine injection and discharge well; oil being discharged; and oil being extracted through the outlet of the main oil switch.

[0014] In some embodiments, when gas or oil needs to be extracted, brine is injected into the bottom channel through the brine injection and discharge well, and natural gas or oil is discharged through the injected brine. The method includes: closing the oil production valve, oil injection valve, oil injection pump, brine discharge valve, gas injection valve and natural gas compressor; opening the brine injection valve, brine injection pump, gas production valve and natural gas main switch; brine entering the bottom channel through the brine injection and discharge well; natural gas being discharged; and gas being extracted through the outlet of the natural gas main switch.

[0015] According to an embodiment of the present invention, a salt cavern storage facility for co-storing oil and natural gas and its operation method have at least the following beneficial effects: brine is injected into the bottom channel, oil is injected into the oil storage salt cavern, and natural gas is injected into the gas storage salt cavern. Because the density of brine is higher than that of oil and natural gas, the brine is kept in the bottom channel. Moreover, the brine is immiscible with oil and natural gas. The brine in the bottom channel isolates the oil and natural gas on both sides, so that the two salt caverns can store natural gas and oil respectively, thereby realizing the co-storage of natural gas and oil. By sharing the middle brine injection and drainage well, two independent circulation processes of gas injection and oil injection are realized, thereby ultimately realizing the co-storage of oil and natural gas in the salt cavern.

[0016] It should be understood that the above general description and the following detailed description are merely exemplary and do not limit this disclosure. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the oil injection and brine discharge operation of a co-storage salt cavern reservoir for oil and natural gas according to an embodiment.

[0019] Figure 2 This is a schematic diagram of the gas injection and brine discharge operation of a co-storage salt cavern storage facility for oil and natural gas according to an embodiment;

[0020] Figure 3 This is a schematic diagram of brine injection and oil recovery operation of a co-storage salt cavern reservoir for oil and gas according to an embodiment;

[0021] Figure 4 This is a schematic diagram of the brine injection and gas production operation of a co-storage salt cavern for oil and natural gas according to an embodiment. The reference numerals are explained as follows: 1. Oil storage salt cavern; 2. Gas storage salt cavern; 3. Bottom channel; 4. Oil injection / production well; 5. Natural gas injection / production well; 6. Brine injection / discharge well; 7. Oil production valve; 8. Oil injection valve; 9. Oil injection pump; 10. Oil buffer device; 11. Oil main switch; 12. Brine discharge valve; 13. Brine injection valve; 14. Brine injection pump; 15. Brine tank; 16. Brine main switch; 17. Gas production valve; 18. Gas injection valve; 19. Natural gas compressor; 20. Natural gas main switch; 21. Lowest interface between oil and brine; 22. Lowest interface between gas and brine; 23. Sediment. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] In the description of this invention, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0024] The terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first," "second," or "third" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0025] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connection," "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0026] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, they are provided so that the description of this disclosure will be more complete and fully convey the concept of the exemplary embodiments to those skilled in the art. The drawings are merely illustrative of this disclosure and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and therefore repeated descriptions of them will be omitted.

[0027] The following is a brief description of the oil and gas co-storage type salt cavern storage facility according to an embodiment of this application:

[0028] According to some embodiments, such as Figure 1As shown, this application provides a salt cavern storage facility for both oil and natural gas, the facility comprising:

[0029] The bottom channel 3 consists of an oil-salt storage cavity 1, a gas-salt storage cavity 2, and a bottom channel 3, with the top two ends of the bottom channel 3 connected to the bottom of the oil-salt storage cavity 1 and the bottom of the gas-salt storage cavity 2, respectively.

[0030] Oil injection well 4, the bottom of which is connected to the top of the oil storage salt cavern 1, and the top of which is connected to an external oil pipeline through the ground.

[0031] Natural gas injection well 5, the bottom of which is connected to the top of the gas storage salt cavern 2, and the top of which is connected to an external natural gas pipeline via the ground;

[0032] The brine injection and drainage well 6 is connected at its bottom to the top middle of the bottom channel 3, and at its top to an external brine pipeline via the ground.

[0033] The oil in the oil storage salt cavern 1 and the natural gas in the gas storage salt cavern 2 are separated by brine in the bottom channel 3. The brine has a higher density than the oil and natural gas and is immiscible with the oil and natural gas.

[0034] Based on the above embodiments, brine is injected into the bottom channel 3, petroleum is injected into the oil storage salt cavern 1, and natural gas is injected into the gas storage salt cavern 2. The density of the brine is higher than that of the petroleum and natural gas, and the brine is immiscible with both. Therefore, the brine remains in the bottom channel 3, while the petroleum and natural gas are located above the brine.

[0035] In some embodiments, the storage tank is provided with an oil-brine minimum interface 21 for oil and brine, and a gas-brine minimum interface 22 for natural gas and brine. The oil-brine interface is not lower than the oil-brine minimum interface 21, and the gas-brine interface is not lower than the gas-brine minimum interface 22. Both the oil-brine minimum interface 21 and the gas-brine minimum interface 22 are higher than the bottom channel 3, so that the storage tank can separate the oil and natural gas through the brine in the bottom channel 3. When the oil-salt storage cavern 1 and the gas-salt storage cavern 2 store oil and natural gas respectively, the operating pressure should be controlled and maintained within a reasonable range to ensure that the pressure difference between the oil-salt storage cavern 1 and the gas-salt storage cavern 2 remains within a reasonable range, thus preventing oil from entering the gas-salt storage cavern 2. In some embodiments, such as... Figure 1 As shown, the oil storage salt cavern 1, the gas storage salt cavern 2, and the bottom channel 3 are all provided with sediment 23.

[0036] This application isolates oil and natural gas on both sides through brine in the bottom channel 3, enabling two salt caverns to store natural gas and oil respectively, thus achieving co-storage of natural gas and oil. By sharing the middle brine injection and drainage well 6, two independent circulation processes of gas injection and oil injection are achieved, ultimately realizing co-storage of oil and natural gas in the salt caverns.

[0037] The following is in conjunction with the appendix to this instruction manual. Figure 1 This paper provides a more detailed description of the oil and gas co-storage salt cavern storage facility proposed in this application.

[0038] According to some embodiments, such as Figure 1 As shown, the external oil pipeline includes an oil production valve 7, an oil injection valve 8, and an oil injection pump 9. The top of the oil injection-production well 4 is connected to one end of the oil production valve 7 and one end of the oil injection pump 9 through an oil pipeline. The other end of the oil injection pump 9 is connected to one end of the oil injection valve 8. The other end of the oil injection valve 8 is used to inject oil into the oil storage salt cavern 1, and the other end of the oil production valve 7 is used to extract oil from the oil storage salt cavern 1.

[0039] Based on the above embodiments, during oil extraction, the oil extraction valve 7 needs to be opened, and the oil injection valve 8 and oil injection pump 9 need to be closed; during oil injection, the oil injection valve 8 and oil injection pump 9 need to be opened, and the oil extraction valve 7 needs to be closed. The oil extraction valve 7 and oil injection valve 8 can prevent external impurities from entering the oil storage salt cavern 1.

[0040] Furthermore, such as Figure 1 As shown, the external oil pipeline also includes an oil buffer device 10. The first end of the oil buffer device 10 is connected to the other end of the oil production valve 7, the second end of the oil buffer device 10 is connected to the other end of the oil injection valve 8, and the third end of the oil buffer device 10 is connected to a pipeline for input or output.

[0041] Furthermore, such as Figure 1 As shown, the external oil pipeline also includes an oil main switch 11, and the third end of the oil buffer device 10 is connected to the oil main switch 11.

[0042] Based on the above embodiments, during oil extraction, the oil extraction valve 7 and the main oil switch 11 need to be opened, and the oil injection valve 8 and the oil injection pump 9 need to be closed; during oil injection, the oil injection valve 8, the oil injection pump 9, and the main oil switch 11 need to be opened, and the oil extraction valve 7 needs to be closed; when neither oil extraction nor injection is performed, the main oil switch 11, the oil extraction valve 7, the oil injection valve 8, and the oil injection pump 9 need to be closed. The main oil switch 11 can prevent external impurities from entering the oil buffer device 10.

[0043] According to some embodiments, such as Figure 1As shown, the natural gas pipeline includes a gas extraction valve 17, a gas injection valve 18, and a natural gas compressor 19. The top of the natural gas injection-production well 5 is connected to one end of the gas extraction valve 17 and one end of the natural gas compressor 19 through a gas transmission pipeline. The other end of the natural gas compressor 19 is connected to one end of the gas injection valve 18. The other end of the gas injection valve 18 is used to inject natural gas into the gas storage salt cavern 2, and the other end of the gas extraction valve 17 is used to extract natural gas from the gas storage salt cavern 2.

[0044] Based on the above embodiments, during gas extraction, the gas extraction valve 17 needs to be opened, and the gas injection valve 18 and natural gas compressor 19 need to be closed; during natural gas injection, the gas injection valve 18 and natural gas compressor 19 need to be opened, and the gas extraction valve 17 needs to be closed. The gas extraction valve 17 and the gas injection valve 18 can prevent external gas from entering the gas storage salt cavern 2.

[0045] According to some embodiments, such as Figure 1 As shown, the natural gas pipeline also includes a natural gas main switch 20, and the other end of the gas injection valve 18 and the other end of the gas extraction valve 17 are both connected to the natural gas main switch 20.

[0046] Based on the above embodiments, when gas is extracted, the gas extraction valve 17 and the natural gas main switch 20 need to be opened, and the gas injection valve 18 and the natural gas compressor 19 need to be closed; when natural gas is injected, the gas injection valve 18, the natural gas compressor 19 and the natural gas main switch 20 need to be opened, and the gas extraction valve 17 needs to be closed; when neither gas is extracted nor injected, the natural gas main switch 20, the gas extraction valve 17, the gas injection valve 18 and the natural gas compressor 19 need to be closed.

[0047] According to some embodiments, such as Figure 1 As shown, the external brine pipeline includes a brine discharge valve 12, a brine injection valve 13, and a brine injection pump 14. The top of the brine injection and discharge well 6 is connected to one end of the brine discharge valve 12 and one end of the brine injection pump 14 through a brine conveying pipeline. The other end of the brine injection pump 14 is connected to one end of the brine injection valve 13. The other end of the brine injection valve 13 is used to inject brine into the bottom channel 3, and the other end of the brine discharge valve 12 is used to discharge brine from the bottom channel 3.

[0048] According to some embodiments, such as Figure 1 As shown, the external brine pipeline also includes a brine tank 15. The first end of the brine tank 15 is connected to the other end of the brine discharge valve 12, the second end of the brine tank 15 is connected to the other end of the brine injection valve 13, and the third end of the brine tank 15 is connected to a pipeline for input or output.

[0049] According to some embodiments, such as Figure 1 As shown, the external brine pipeline also includes a brine main switch 16, and the third end of the brine tank 15 is connected to the brine main switch 16.

[0050] The operation method of the oil and gas co-storage type salt cavern storage according to the embodiments of this application is briefly described below:

[0051] According to some embodiments, such as Figures 1 to 4 As shown, this application provides an operation method for a salt cavern storage facility that combines oil and natural gas storage, the operation method comprising:

[0052] Step 101: Brine is injected into the bottom channel 3 through the brine injection and drainage well 6. When the brine fills the bottom channel 3, the oil and salt storage cavern 1, the gas storage cavern 2, the oil injection and production well 4, the natural gas injection and production well 5, and the brine injection and drainage well 6, the brine injection is stopped.

[0053] Step 102: Inject oil into the oil-salt cavern 1 through the oil injection-production well 4 and discharge the brine. When the oil-brine interface between the oil and the brine reaches the lowest oil-brine interface 21, stop injecting oil.

[0054] Step 103: Inject natural gas into the gas storage salt cavern 2 through the natural gas injection-production well 5 and discharge the brine. When the gas-brine interface between the natural gas and the brine reaches the lowest gas-brine interface 22, stop injecting natural gas.

[0055] Step 104: When gas or oil needs to be extracted, brine is injected into the bottom channel 3 through the brine injection well 6, and natural gas or oil is discharged through the injected brine.

[0056] In step 101, the oil production valve 7, the main oil switch 11, the gas production valve 17, the main natural gas switch 20, the brine injection valve 13, and the brine injection pump 14 are opened; the oil injection valve 8, the oil injection pump 9, the gas injection valve 18, and the natural gas compressor 19 are closed. Brine is then introduced into the bottom channel 3, the oil storage salt cavern 1, the gas storage salt cavern 2, the oil injection-production well 4, the natural gas injection-production well 5, and the brine injection-discharge well 6 through the brine injection valve 13 and the brine injection pump 14. When the bottom channel 3, the oil storage salt cavern 1, the gas storage salt cavern 2, the oil injection-production well 4, the natural gas injection-production well 5, and the brine injection-discharge well 6 are filled with brine, the brine injection is stopped.

[0057] The following is in conjunction with the appendix to this instruction manual. Figures 1 to 4 The operating method of the oil and gas co-storage salt cavern storage facility described in this application is further elaborated in detail.

[0058] According to some embodiments, in step 102, oil is injected into the oil-salt cavern 1 through the oil injection-production well 4, and brine is discharged. When the oil-brine interface reaches the lowest oil-brine interface 21, the injection of oil is stopped. The method includes:

[0059] Close the gas injection valve 18, gas production valve 17, natural gas compressor 19, oil production valve 7, brine injection valve 13, and brine injection pump 14. Open the oil injection valve 8, oil injection pump 9, oil main switch 11, brine main switch 16, and brine discharge valve 12. The oil enters the oil buffer device 10 through the oil main switch 11, and then enters the oil storage salt cavern 1 through the oil injection valve 8, oil injection pump 9, and oil injection-production well 4.

[0060] Based on the above embodiments, such as Figure 1 As shown, during oil injection: the gas injection valve 18, gas production valve 17, and natural gas compressor 19 are closed; the oil production valve 7, brine injection valve 13, and brine injection pump 14 are closed; and the oil injection valve 8, oil injection pump 9, main oil switch 11, main brine switch 16, and brine discharge valve 12 are opened. Oil enters the oil buffer device 10 through the external oil pipeline and main oil switch 11, passes through oil injection valve 8 and oil injection pump 9, and then enters the oil storage salt cavern 1 through the oil injection-production well 4. The oil storage salt cavern 1, gas storage salt cavern 2, and bottom channel 3 are equipped with sediment 23. During oil injection, oil enters the gaps between the sediment particles 23, causing the oil-brine interface to continuously decrease. The oil-brine interface cannot exceed the lowest oil-brine interface 21. The brine enters the brine injection-discharge well 6 through the bottom channel 3, and finally enters the brine tank 15 through the brine discharge valve 12, thus completing the oil injection process. When the brine volume in the brine tank 15 reaches a certain value, it can be discharged through the main brine switch 16 or directly extracted.

[0061] According to some embodiments, in step 103, natural gas is injected into the gas storage salt cavern 2 through the natural gas injection-production well 5, and brine is discharged. When the gas-brine interface between the natural gas and the brine reaches the lowest gas-brine interface 22, the injection of natural gas is stopped. The method includes:

[0062] Close oil production valve 7, oil injection valve 8, oil injection pump 9, brine injection valve 13, brine injection pump 14 and gas production valve 17, and open brine discharge valve 12, brine main switch 16, natural gas main switch 20, gas injection valve 18 and natural gas compressor 19. Natural gas enters gas storage salt cavern 2 through natural gas main switch 20, gas injection valve 18, natural gas compressor 19 and natural gas injection-production well 5.

[0063] Based on the above embodiments, such as Figure 2As shown, during gas injection: Oil production valve 7, oil injection valve 8, oil injection pump 9, brine injection valve 13, brine injection pump 14, and gas production valve 17 are closed; brine discharge valve 12, brine main switch 16, natural gas main switch 20, gas injection valve 18, and natural gas compressor 19 are opened. Sediment 23 is installed in the oil storage salt cavern 1, gas storage salt cavern 2, and bottom channel 3. Natural gas enters the natural gas main switch 20 and gas injection valve 18 through an external natural gas pipeline, then proceeds to the natural gas compressor 19, and finally enters the gas storage salt cavern 2 through the natural gas injection-production well 5. With continuous natural gas injection, natural gas enters the gaps between the sediment particles 23, eventually filling the gas storage salt cavern 2. The gas-brine interface continuously decreases, and the gas-brine interface must not exceed the lowest gas-brine interface 22. Brine enters the brine tank 15 through the bottom channel 3, brine injection-discharge well 6, and brine discharge valve 12, thus completing the gas injection process.

[0064] Furthermore, during the processes of oil injection and brine discharge, and gas injection and brine discharge, negative pressure is not allowed at the wellhead of well 6 in the brine injection and discharge well.

[0065] Through the above-described oil and gas injection methods, two salt caverns were used to store oil and natural gas separately without mixing them, thus achieving the co-storage of oil and natural gas.

[0066] According to some embodiments, in step 104, when gas or oil needs to be extracted, brine is injected into the bottom channel 3 through the brine injection / discharge well 6, and natural gas or oil is discharged through the injected brine. The method includes:

[0067] Close the gas injection valve 18, gas production valve 17, natural gas compressor 19, oil injection valve 8, oil injection pump 9, and brine discharge valve 12. Open the main oil switch 11, oil production valve 7, brine injection valve 13, and brine injection pump 14. Brine enters the bottom channel 3 through the brine injection and discharge well 6, and oil is discharged. Oil is extracted through the outlet of the main oil switch 11.

[0068] Based on the above embodiments, such as Figure 3 As shown, during oil extraction: the gas injection valve 18, gas production valve 17, and natural gas compressor 19 are closed; the main oil switch 11, oil production valve 7, brine injection valve 13, and brine injection pump 14 are opened; the oil injection valve 8, oil injection pump 9, and brine discharge valve 12 are closed. Under the action of the brine injection pump 14, the brine passes through the brine injection and discharge well 6, through the bottom channel 3 of the salt cavern, and enters the oil storage salt cavern 1. The oil-brine interface rises, and the oil passes through the oil injection and production well 4 and the oil production valve 7 into the oil buffer device 10. The oil in the oil buffer device 10 then enters the oil tank or oil tanker through the main oil switch 11, thus realizing the oil extraction process.

[0069] According to some embodiments, in step 104, when gas or oil needs to be extracted, brine is injected into the bottom channel 3 through the brine injection / discharge well 6, and natural gas or oil is discharged through the injected brine. The method includes:

[0070] Close the oil production valve 7, oil injection valve 8, oil injection pump 9, brine discharge valve 12, gas injection valve 18 and natural gas compressor 19, open the brine injection valve 13, brine injection pump 14, gas production valve 17 and natural gas main switch 20, brine enters the bottom channel 3 through brine injection and discharge well 6, natural gas is discharged, and gas is taken out through the outlet of natural gas main switch 20.

[0071] Based on the above embodiments, such as Figure 4 As shown, during gas extraction: close the oil extraction valve 7, oil injection valve 8, oil injection pump 9, and brine discharge valve 12; open the brine injection valve 13, gas extraction valve 17, and natural gas main switch 20; and close the gas injection valve 18 and natural gas compressor 19. Natural gas in the gas storage salt cavern 2 will be discharged from the gas storage salt cavern 2 under the action of external atmospheric pressure. If you want to increase the gas extraction rate or the gas extraction volume, you can open the brine injection pump 14 to inject brine into the salt cavern. The brine enters the brine injection / discharge well 6 through the brine injection valve 13 and the brine injection pump 14, and then enters the gas storage salt cavern 2 through the bottom channel 3 of the salt cavern. The gas-brine interface rises, and natural gas enters the natural gas storage tank (or natural gas buffer pool) through the natural gas injection / production well 5, the gas extraction valve 17, and the natural gas main switch 20, thus realizing the gas extraction process.

[0072] Through the above-mentioned oil and gas extraction methods, oil and natural gas were extracted from two salt caverns separately, and the extraction processes of the two processes did not affect each other, thus realizing the independent extraction of oil and natural gas stored in the salt caverns.

[0073] The two salt caverns can also store other media with similar physical properties to oil and natural gas.

[0074] In the description of the above embodiments, specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.

[0075] Although this disclosure has been described with reference to several typical embodiments, it should be understood that the terminology used is descriptive and exemplary, and not restrictive. Because this disclosure can be embodied in many forms without departing from the spirit or substance of this application, it should be understood that the above embodiments are not limited to any of the foregoing details, but should be interpreted broadly within the spirit and scope defined by the appended claims. Therefore, all variations and modifications falling within the scope of the claims or their equivalents should be covered by the appended claims.

Claims

1. A salt cavern storage facility for both oil and natural gas, characterized in that, The storage facility includes: The bottom channel comprises an oil-salt storage cavity, a gas-salt storage cavity, and a bottom channel, wherein the top two ends of the bottom channel are respectively connected to the bottom of the oil-salt storage cavity and the bottom of the gas-salt storage cavity; An oil injection-production well, the bottom of which is connected to the top of the oil-salt storage pit, and the top of which is connected to an external oil pipeline via the ground. A natural gas injection-production well, the bottom of which is connected to the top of the gas storage salt cavern, and the top of which is connected to an external natural gas pipeline via the ground; A brine injection and drainage well, wherein the bottom of the brine injection and drainage well is connected to the top middle of the bottom channel, and the top of the brine injection and drainage well is connected to an external brine pipeline through the ground. The oil in the oil storage salt cavern and the natural gas in the gas storage salt cavern are separated by brine in the bottom channel. The brine has a higher density than the oil and natural gas and is immiscible with the oil and natural gas. The storage tank is provided with a minimum oil-brine interface between oil and brine, and a minimum gas-brine interface between natural gas and brine. The oil-brine interface between oil and brine is not lower than the minimum oil-brine interface, and the gas-brine interface between natural gas and brine is not lower than the minimum gas-brine interface. Both the minimum oil-brine interface and the minimum gas-brine interface are higher than the bottom channel, so that the storage tank can separate the oil and natural gas through the brine in the bottom channel. The oil storage salt cavern, gas storage salt cavern, and bottom channel are all equipped with sediment.

2. The oil and natural gas co-storage salt cavern storage facility according to claim 1, characterized in that, The external oil pipeline includes an oil production valve, an oil injection valve, and an oil injection pump. The top of the oil injection-production well is connected to one end of the oil production valve and one end of the oil injection pump via an oil pipeline. The other end of the oil injection pump is connected to one end of the oil injection valve. The other end of the oil injection valve is used to inject oil into the oil storage salt cavern, and the other end of the oil production valve is used to extract oil from the oil storage salt cavern. The external oil pipeline also includes an oil buffer device, the first end of which is connected to the other end of the oil production valve, the second end of which is connected to the other end of the oil injection valve, and the third end of which is connected to a pipeline for input or output. The external oil pipeline also includes a main oil switch, and the third end of the oil buffer device is connected to the main oil switch.

3. The oil and natural gas co-storage salt cavern storage facility according to claim 1, characterized in that, The external brine pipeline includes a brine discharge valve, a brine injection valve, and a brine injection pump. The top of the brine injection and discharge well is connected to one end of the brine discharge valve and one end of the brine injection pump through a brine conveying pipeline. The other end of the brine injection pump is connected to one end of the brine injection valve. The other end of the brine injection valve is used to inject brine into the bottom channel, and the other end of the brine discharge valve is used to discharge brine from the bottom channel. The external brine pipeline also includes a brine tank, the first end of which is connected to the other end of the brine discharge valve, the second end of which is connected to the other end of the brine injection valve, and the third end of which is connected to a pipeline for input or output. The external brine pipeline also includes a brine master switch, and the third end of the brine tank is connected to the brine master switch.

4. The oil and natural gas co-storage salt cavern storage facility according to claim 1, characterized in that, The natural gas pipeline includes a gas extraction valve, a gas injection valve, and a natural gas compressor. The top of the natural gas injection-production well is connected to one end of the gas extraction valve and one end of the natural gas compressor via a gas transmission pipeline. The other end of the natural gas compressor is connected to one end of the gas injection valve. The other end of the gas injection valve is used to inject natural gas into the gas storage salt cavern, and the other end of the gas extraction valve is used to extract natural gas from the gas storage salt cavern. The natural gas pipeline also includes a main natural gas switch, and the other end of the gas injection valve and the other end of the gas extraction valve are both connected to the main natural gas switch.

5. An operation method for a co-storage salt cavern storage facility for oil and natural gas, the method being applied to the co-storage salt cavern storage facility for oil and natural gas as described in claim 1, characterized in that, The operating method includes: Brine is injected into the bottom channel through brine injection and drainage wells. When the bottom channel, oil and salt storage caverns, gas and salt storage caverns, oil injection and production wells, natural gas injection and production wells, and brine injection and drainage wells are filled with brine, the injection of brine is stopped. Oil is injected into the oil-salt cavern through an oil injection-production well, and brine is discharged. When the oil-brine interface reaches the lowest oil-brine interface, the oil injection is stopped. Natural gas is injected into the gas storage salt cavern through natural gas injection and production wells, and brine is discharged. When the gas-brine interface between natural gas and brine reaches the lowest gas-brine interface, the injection of natural gas is stopped. When gas or oil needs to be extracted, brine is injected into the bottom channel through the brine injection and discharge well, and natural gas or oil is discharged through the injected brine.

6. The operating method according to claim 5, characterized in that, The method involves injecting oil into an oil-salt reservoir through an oil injection-production well, discharging brine, and stopping oil injection when the oil-brine interface reaches the minimum oil-brine interface. Close the gas injection valve, gas production valve, natural gas compressor, oil production valve, brine injection valve, and brine injection pump. Open the oil injection valve, oil injection pump, main oil switch, main brine switch, and brine discharge valve. The oil enters the oil buffer device through the main oil switch, and then enters the oil storage salt cavern through the oil injection valve, oil injection pump, and oil injection-production well.

7. The operating method according to claim 5, characterized in that, The method involves injecting natural gas into a gas-brine cavern through a natural gas injection-production well, discharging brine, and stopping the injection of natural gas when the gas-brine interface reaches its minimum. Close the oil production valve, oil injection valve, oil injection pump, brine injection valve, brine injection pump, and gas production valve. Open the brine discharge valve, brine main switch, natural gas main switch, gas injection valve, and natural gas compressor. Natural gas enters the gas storage salt cavern through the natural gas main switch, gas injection valve, natural gas compressor, and natural gas injection / production well.

8. The operating method according to claim 5, characterized in that, When gas or oil extraction is required, brine is injected into the bottom channel through the brine injection well, and natural gas or oil is discharged through the injected brine. The method includes: Close the gas injection valve, gas production valve, natural gas compressor, oil injection valve, oil injection pump, and brine discharge valve. Open the main oil switch, oil production valve, brine injection valve, and brine injection pump. Brine enters the bottom channel through the brine injection and discharge well, and oil is discharged through the outlet of the main oil switch.

9. The operating method according to claim 5, characterized in that, When gas or oil extraction is required, brine is injected into the bottom channel through the brine injection well, and natural gas or oil is discharged through the injected brine. The method includes: Close the oil production valve, oil injection valve, oil injection pump, brine discharge valve, gas injection valve, and natural gas compressor. Open the brine injection valve, brine injection pump, gas production valve, and natural gas main switch. Brine enters the bottom channel through the brine injection and discharge well, and natural gas is discharged and extracted through the outlet of the natural gas main switch.

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