Underwater oil storage system

Abstract

The utility model provides an underwater oil storage system. The underwater oil storage system comprises an underwater oil tank, an oil-water separation tank and a water tank, a communicating pipe is arranged in the oil tank, a first communicating opening of the communicating pipe is communicated with the oil tank and located at the bottom of the oil tank, a second communicating opening of the communicating pipe is communicated with the oil-water separation tank and located at the top of the oil-water separation tank, and an oil-water separator, a first connecting pipe, a second connecting pipe and a third connecting pipe are arranged in the oil-water separation tank, an external connector of the first connecting pipe is located at the bottom of the oil-water separation cabin, an outlet of the second connecting pipe is communicated with the oil cabin, and an external connector of the third connecting pipe is communicated with the water cabin so that water separated by the oil-water separator can be conveyed into the water cabin. According to the utility model, the exploitation rate of crude oil is improved, the crude oil storage capacity in unit oil storage space is improved, and the defect of insufficient oil storage space is overcome.

Description

Technical Field

[0001] The utility model relates to the field of offshore crude oil storage, in particular to an underwater oil storage system. Background Art

[0002] The receipt and storage of crude oil all rely on large oil depots. Therefore, the concept of offshore oil depots came into being. Crude oil produced and transported offshore can be stored in offshore oil depots, saving the construction resources of docks and land.

[0003] In the prior art, floating tankers can be used to store crude oil. However, due to the size of the tankers, the oil tank storage capacity is small. At the same time, due to the influence of offshore wind volume and climate conditions, floating tankers cannot be installed and arranged on a large scale, which seriously limits the storage scale of crude oil. Fixed production platforms combined with floating oil storage tankers, fixed wellhead platforms combined with floating production storage devices, self-elevating production storage and unloading devices combined with shuttle tankers can be used for development. However, the above solutions are all limited by variable loads. For example, the platform needs to meet various requirements such as production, power, storage and transportation, external transmission and life, and its oil storage space is greatly compressed, and the recovery rate of crude oil is low. Utility Model Content

[0004] The utility model provides an underwater oil storage system, which solves the problems existing in the prior art of small oil storage space, great influence by ocean waves and low crude oil recovery rate.

[0005] The utility model provides an underwater oil storage system, comprising an underwater oil tank, an oil-water separation tank and a water tank;

[0006] An oil inlet pipe is provided in the oil tank, and crude oil enters the oil tank through the oil inlet pipe; a connecting pipe is provided in the oil tank, a first connecting port of the connecting pipe is connected to the oil tank and is located at the bottom of the oil tank, and a second connecting port of the connecting pipe is connected to the oil-water separation cabin and is located at the top of the oil-water separation cabin, so as to transport the oil-water mixture below the oil-water interface in the oil tank to the oil-water separation cabin;

[0007] An oil-water separator and a first connecting pipe, a second connecting pipe and a third connecting pipe connected to the oil-water separator are arranged in the oil-water separation cabin. The external interface of the first connecting pipe is located at the bottom of the oil-water separation cabin to transport the oil-water mixture to the oil-water separator. The outlet of the second connecting pipe is connected to the oil tank to transport the oil separated by the oil-water separator to the oil tank. The external interface of the third connecting pipe is connected to the water tank to transport the water separated by the oil-water separator to the water tank.

[0008] The embodiment of the utility model can not only save floating oil storage equipment and greatly reduce production and construction costs, but also utilize the density difference between oil and water to make the oil-water mixture circulate in the three tanks in an orderly manner and then be efficiently separated, greatly reducing the loss of crude oil mixed with water, improving the recovery rate of crude oil, and increasing the crude oil storage capacity per unit oil storage space, improving the defect of insufficient oil storage space, and because the entire device of the embodiment of the utility model is located underwater, it can greatly reduce the influence of wind volume at sea level.

[0009] Optionally, the underwater oil storage system further includes a circulating oil pump, and the outlet of the second connecting pipe is connected to the oil inlet pipe through the circulating oil pump to transport the oil separated by the oil-water separator to the oil tank.

[0010] Optionally, the underwater oil storage system also includes a dirty oil pipe, one interface of the dirty oil pipe is connected to the water tank and is located on the top of the water tank, and the other interface of the dirty oil pipe is connected to the pipe section in the second connecting pipe located upstream of the circulating oil pump.

[0011] The utility model embodiment can transport the oil flower layer on the top of the water tank to the circulating oil pump and then enter the oil tank through the arrangement of the dirty oil pipe, further improving the recovery rate of crude oil, thereby improving the crude oil production rate and avoiding waste of resources.

[0012] Optionally, the underwater oil storage system also includes an emulsion inlet pipe and an emulsion outlet pipe, the emulsion inlet pipe is connected to a pipe section in the second connecting pipe located upstream of the circulating oil pump, and the emulsion outlet pipe is connected to a pipe section in the second connecting pipe located downstream of the circulating oil pump.

[0013] The embodiment of the utility model provides an emulsion inlet pipe and an emulsion outlet pipe, so that the emulsion in the oil-water mixture can be extracted by a circulating oil pump to avoid corrosion of the pipeline and the equipment flowing through it, which is beneficial to improving the service life of the underwater oil storage system.

[0014] Optionally, the underwater oil storage system further includes a chemical agent pipe, which is connected to the connecting pipe in the oil tank and the first connecting pipe in the oil-water separation cabin.

[0015] The embodiment of the utility model can improve the emulsification of crude oil by injecting chemicals into the pipeline through the arrangement of the chemical agent pipe, further improve the oil-water separation efficiency, and thus improve the crude oil recovery rate.

[0016] Optionally, an oil outlet pipe is further provided in the oil tank, and the outlets of the oil inlet pipe and the inlet of the oil outlet pipe are both multiple, and the multiple outlets of the oil inlet pipes and the multiple inlet of the oil outlet pipes are evenly arranged in a ring along the side wall of the oil tank.

[0017] The multiple oil inlet pipe outlets and the oil outlet pipe inlet of the embodiment of the utility model are arranged in a ring along the side wall of the oil tank, which can reduce the disturbance of the medium in the oil tank when the crude oil enters and exits the oil tank, reduce the disturbance of the oil-water interface, and is conducive to improving the accuracy of oil-water separation in the underwater oil storage system.

[0018] Optionally, an unloading pump is provided on the oil outlet pipe, and the crude oil in the oil tank is transported to the outside through the oil outlet pipe and the unloading pump.

[0019] Optionally, the underwater oil storage system further comprises a heated liquid supply pipe, a heated coil and a heated liquid return pipe;

[0020] The heating coil is arranged in the oil tank, the inlet of the heating coil is connected to the heating liquid supply pipe, and the outlet of the heating coil is connected to the heating liquid return pipe.

[0021] The embodiment of the utility model can heat the crude oil in the oil tank by arranging the heating liquid supply pipe, the heating coil and the heating liquid return pipe, so as to maintain the storage temperature of the crude oil and avoid wax precipitation and solidification of the crude oil.

[0022] Optionally, a water outlet pipe and a water inlet pipe are provided in the water tank; the inlet of the water outlet pipe and the outlet of the water inlet pipe are connected to the water tank, and the inlet of the water outlet pipe, the outlet of the water outlet pipe, the inlet of the water inlet pipe and the outlet of the water inlet pipe are all located at the bottom of the water tank. The water outlet pipe arranged in this way can prevent the dirty oil on the top of the water tank from being discharged from the water tank to pollute the seawater, and the water inlet pipe arranged in this way can avoid disturbing the dirty oil layer on the top, resulting in the oil-water mixed dirty oil in the water tank being discharged from the water outlet pipe.

[0023] Optionally, the oil tank, the oil-water separation tank and the water tank are distributed in parallel in the same direction; or, the oil tank and the water tank are distributed in parallel in the same direction, and the oil-water separation tank and the water tank are distributed in parallel in another direction. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic diagram of the structure of the underwater oil storage system of the embodiment of the utility model, wherein the oil tank, the oil-water separation tank and the water tank are arranged in parallel in the same direction;

[0025] Figure 2 This is a schematic diagram of the layout of the outlets of multiple oil inlet pipes of the oil tank of the underwater oil storage system according to an embodiment of the utility model;

[0026] Figure 3 This is a schematic diagram of the structure of the underwater oil storage system of an embodiment of the utility model, wherein the oil tank and the water tank are arranged in parallel in the same direction, and the oil-water separation tank and the water tank are arranged in parallel in another direction;

[0027] Figure 4-5 All of them are schematic diagrams of the cabin layout of the underwater oil storage system according to the embodiments of the present utility model.

[0028] Description of reference numerals:

[0029] 1: Underwater oil storage system;

[0030] 11: oil tank; 110: insulation layer; 111: oil inlet pipe; 1110: outlet; 112: oil outlet pipe; 113: connecting pipe;

[0031] 12: oil-water separation cabin; 121: oil-water separator; 121A: first connecting pipe; 121B: second connecting pipe; 121C: third connecting pipe;

[0032] 13: water tank; 131: dirty oil pipe; 132: water outlet pipe; 133: water inlet pipe;

[0033] 141: circulating oil pump; 142: unloading pump;

[0034] 151: emulsion inlet pipe; 152: emulsion outlet pipe;

[0035] 16: Chemical pipe;

[0036] 171: Heating liquid supply pipe; 172: Heating liquid return pipe; 173: Heating coil. DETAILED DESCRIPTION

[0037] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and a specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0038] It should be noted that in this specification, similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings.

[0039] In the description of this embodiment, it should be noted that the terms "upper", "lower", "inner", "bottom", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which the utility model product is usually placed when in use. They are only for the convenience of describing the utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the utility model.

[0040] The terms “first”, “second”, etc. are only used for distinguishing descriptions and should not be understood as indicating or implying relative importance.

[0041] In the description of this embodiment, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this embodiment can be understood according to specific circumstances.

[0042] In order to make the purpose, technical solution and advantages of the present invention more clear, the implementation mode of the present invention will be further described in detail below with reference to the accompanying drawings.

[0043] The utility model provides an underwater oil storage system 1, which can be used as a fixed tank sunk to the bottom and fixed on the seabed, and can also be used for offshore oil field development to store produced crude oil.

[0044] For details, see Figure 1 The underwater oil storage system 1 includes an oil tank 11, an oil-water separation tank 12 and a water tank 13 located underwater.

[0045] The oil tank 11 is the main storage tank, the oil-water separation tank 12 is used to store the oil-water interface medium in the oil tank, and the water tank 13 is mainly used to store ballast water during crude oil loading and unloading. The loading and unloading of crude oil is achieved through underwater oil-water displacement. The crude oil enters the oil tank 11 and squeezes the seawater to flow to the oil-water separation tank 12. The oil and water are separated by the oil-water separator 121 at the bottom of the oil-water separation tank 12. The water flows into the water tank 13, and the separated crude oil returns to the oil tank 11. During unloading, the seawater is squeezed into the oil tank 11 through the water tank 13, and then the crude oil is replaced to complete the unloading.

[0046] An oil inlet pipe 111 is provided in the oil tank 11, and crude oil enters the oil tank 11 through the oil inlet pipe 111. A connecting pipe 113 is provided in the oil tank 11, a first connecting port of the connecting pipe 113 is connected to the oil tank 11 and is located at the bottom of the oil tank, and a second connecting port of the connecting pipe 113 is connected to the oil-water separation cabin 12 and is located at the top of the oil-water separation cabin, so as to transport the oil-water mixture below the oil-water interface in the oil tank 11 to the oil-water separation cabin 12.

[0047] An oil-water separator 121 (e.g., an oil-water coalescer) and a first connecting pipe 121A, a second connecting pipe 121B, and a third connecting pipe 121C connected to the oil-water separator are provided in the oil-water separation cabin 12. The external interface of the first connecting pipe 121A is located at the bottom of the oil-water separation cabin 12 to transport the oil-water mixture to the oil-water separator 121. The outlet of the second connecting pipe 121B is connected to the oil tank 11 to transport the oil separated by the oil-water separator 121 to the oil tank 11. The external interface of the third connecting pipe 121C is connected to the water tank 13 to transport the water separated by the oil-water separator 121 to the water tank 13.

[0048] The embodiment of the utility model can not only save floating oil storage equipment and greatly reduce production and construction costs, but also make use of the difference in oil-water density to make the oil-water mixture circulate in the three tanks in an orderly manner and then be separated efficiently, greatly reduce the loss of crude oil mixed in water, improve the recovery rate of crude oil, increase the storage capacity of crude oil per unit oil storage space, improve the defect of insufficient oil storage space, and because the entire device of the embodiment of the utility model is located underwater, it can greatly reduce the influence of wind volume at sea level.

[0049] In one embodiment, the connecting pipe 113 may be, for example, disposed through the side wall of the oil tank 11, and the oil-water mixture can only be connected to the oil tank 11 and the oil-water separation cabin 12 through the connecting pipe 113. In one embodiment, the oil-water separator 121 may be welded to the inner wall of the oil-water separation cabin 12, and the oil and water can only enter the oil-water separator 121 through the first connecting pipe 121A. In other alternative embodiments, the oil-water separator 121 may also be disposed outside the oil-water separation cabin 12.

[0050] See also Figure 2 , Figure 2It can be understood as a cross-sectional schematic diagram of an oil tank. In one embodiment, the outlet of the oil inlet pipe 111 of the oil tank 11 may be, for example, multiple, and the outlets 1110 of the multiple oil inlet pipes 111 are evenly arranged in an annular shape along the side wall of the oil tank 11. Further, the side wall of the oil tank 11 is also provided with an oil outlet pipe 112, and the inlet of the oil outlet pipe 112 is provided on the side wall of the oil tank 11. The inlet of the oil outlet pipe 112 may also be multiple, and the inlet of the multiple oil outlet pipes may also be evenly arranged in an annular shape along the side wall of the oil tank 11. The structure in which the outlets 1110 of the multiple oil inlet pipes 111 and the inlet of the oil outlet pipe 112 are all arranged in an annular shape along the side wall of the oil tank 11 can reduce the disturbance of the medium in the oil tank when the crude oil enters and leaves the oil tank, reduce the disturbance of the oil-water interface, and help improve the accuracy of oil-water separation in the underwater oil storage system. Among them, the oil inlet pipe 111 and the oil outlet pipe 112 are independent pipelines to achieve simultaneous operation of production and unloading.

[0051] For further information, see Figure 1 and Figure 3 The layout of the oil tank 11, the oil-water separation tank 12 and the water tank 13 is not limited. In one embodiment, Figure 1 As shown, the oil tank 11, the oil-water separation tank 12 and the water tank 13 are arranged in parallel along the same direction (for example, the horizontal direction shown in the figure). In other alternative embodiments, Figure 3 As shown, the oil tank 11 and the water tank 13 are arranged side by side in the same direction (eg, the horizontal direction as shown), and the oil-water separation tank 12 and the water tank 13 are arranged side by side in another direction (eg, the vertical direction as shown).

[0052] It can be understood by those skilled in the art that the present invention has no limitation on the shape, quantity and material of each cabin. Figure 4 and Figure 5 For example, the cabin can be a cubic structure or a cylindrical structure, and the bottom shape of each cabin can be a circular cylindrical flat bottom, a rectangular cylindrical flat bottom, an elliptical head circular cylindrical flat bottom, a hemispherical head circular cylindrical flat bottom, a sphere, etc. Further, the number of the oil tank 11, the oil-water separation tank 12 and the water tank 13 can also be multiple, for example Figure 4 and Figure 5 As shown, the number of oil tanks 11 is 6. In other alternative embodiments, the number may be other, and the number of other tanks may also be multiple. The material of each tank may be, for example, steel structure material, cement material, or a composite material of steel structure and cement.

[0053] In one implementation, see Figure 1 and Figure 3The underwater oil storage system 1 also includes a circulating oil pump 141. The outlet of the second connecting pipe 121B is connected to the oil inlet pipe 111 through the circulating oil pump 141 to transport the oil separated by the oil-water separator 121 to the oil tank 11. Furthermore, it also includes a dirty oil pipe 131. One interface of the dirty oil pipe 131 is connected to the water tank 13 and is located at the top of the water tank 13. The other interface of the dirty oil pipe 131 is connected to the pipe section located upstream of the circulating oil pump 141 in the second connecting pipe 121B. The dirty oil pipe 131 with such a structure can transport the oil flower layer on the top of the water tank to the circulating oil pump 141 and then enter the oil tank 11, further improving the recovery rate of crude oil, thereby improving the crude oil production rate and avoiding resource waste.

[0054] In one implementation, see Figure 1 and Figure 3 The underwater oil storage system 1 further includes an emulsion inlet pipe 151 and an emulsion outlet pipe 152. The emulsion inlet pipe 151 is connected to a pipe section in the second connecting pipe 121B located upstream of the circulating oil pump 141, and the emulsion outlet pipe 152 is connected to a pipe section in the second connecting pipe 121B located downstream of the circulating oil pump 141. The embodiment of the utility model can use the circulating oil pump 141 to extract the emulsion in the oil-water mixture by setting the emulsion inlet pipe 151 and the emulsion outlet pipe 152, thereby avoiding corrosion of the emulsion to the pipeline and the equipment flowing through, which is conducive to improving the service life of the underwater oil storage system.

[0055] Furthermore, the underwater oil storage system 1 further includes a chemical agent pipe 16, which is connected to the connecting pipe 113 in the oil tank 11 and the first connecting pipe in the oil-water separation tank 12. The embodiment of the utility model can improve the emulsification of crude oil by injecting chemicals into the pipeline through the chemical agent pipe 16, further improve the oil-water separation efficiency, and thus improve the crude oil recovery rate.

[0056] In one implementation, see Figure 1 and Figure 3, an unloading pump 142 is provided on the oil outlet pipe 112, and the crude oil in the oil tank 11 is transported to the outside through the oil outlet pipe 112 and the unloading pump 142. Among them, the unloading pump 142 can be located in the oil tank 11, and in other alternative embodiments, it can also be located outside the oil tank 11. Furthermore, in one embodiment, the underwater oil storage system 1 also includes a heating supply pipe 171, a heating coil 173 and a heating return pipe 172. The heating coil 173 is coiled in the oil tank, the inlet of the heating coil 173 is connected to the heating supply pipe 171, and the outlet of the heating coil 173 is connected to the heating return pipe 172. Among them, in an exemplary embodiment, the heating medium in the heating coil 173 can be hot water or other high-temperature media. By providing the heating supply pipe 171, the heating coil 173 and the heating return pipe 172, the crude oil in the oil tank 11 can be heated to maintain the storage temperature of the crude oil and avoid wax precipitation and solidification of the crude oil. In one embodiment, as Figure 1 As shown, the outer wall of the oil tank 11 is provided with an insulation layer 110 to further maintain the storage temperature of the crude oil.

[0057] Further, in one embodiment, a water outlet pipe 132 and a water inlet pipe 133 are provided in the water tank 13. The inlet of the water outlet pipe 132 and the outlet of the water inlet pipe 133 are connected to the water tank 13, and the inlet of the water outlet pipe 132, the outlet of the water outlet pipe 132, the inlet of the water inlet pipe 133 and the outlet of the water inlet pipe 133 are all located at the bottom of the water tank. The water outlet pipe 132 arranged in this way can prevent the dirty oil on the top of the water tank 13 from being discharged from the water tank 13 to pollute the seawater, and the water inlet pipe 133 arranged in this way can avoid disturbing the dirty oil layer on the top, resulting in the oil-water mixed dirty oil in the water tank 13 being discharged from the water outlet pipe 132.

[0058] Furthermore, in one embodiment, a plurality of sensors are provided in the underwater oil storage system, for example, an oil-water interface monitor is provided at the bottom of the oil tank 11, which is used to control the loading of crude oil to prevent the crude oil from entering the oil-water separation tank 12. In one embodiment, a temperature sensor is provided in the oil tank 11, and the temperature sensor and the oil-water interface monitor work together to monitor the storage temperature of the crude oil. Once the temperature of the crude oil drops to the alarm value, the corresponding valves of the heating liquid supply pipe 171 and the heating liquid return pipe 172 are automatically opened to heat the crude oil. In one embodiment, a discharge water oil content monitor is provided in the oil tank 11, and the oil-water interface monitor and the discharge water oil content monitor work together to monitor the emulsification degree of the crude oil. According to specific needs, the chemical agent pipe 16 is activated, and chemical agents are injected into the connecting pipe 113 of the oil tank 11 and the first connecting pipe 121A in the oil-water separation tank 12 to reduce the emulsification degree of the crude oil, so as to improve the separation efficiency of oil and water and meet the requirements of the discharge water oil content.

[0059] The working process of the underwater oil storage system 1 of the embodiment of the present application is described below. Figure 1 and Figure 3understand.

[0060] When loading crude oil, the crude oil enters the oil tank 11 through the oil inlet pipe 111 and the outlet of the oil inlet pipe 111 arranged around the side wall of the oil tank 11, so as to avoid disturbing the oil-water interface and causing crude oil emulsification. As the crude oil continues to enter the oil tank 11, the water at the bottom of the tank is squeezed through the connecting pipe 113 and enters the oil-water separation tank 12 from the top until the oil-water interface area enters the oil-water separation tank. The oil-water interface monitor is set at the bottom of the oil tank to control the loading of crude oil to avoid crude oil entering the oil-water separation tank. The volume capacity of the oil-water separation tank can store the oil-water interface area, which serves as the first barrier to prevent a large amount of crude oil from entering the water tank 13. The oil-water interface is separated again by gravity at the top of the oil-water separation tank 12, and the water carrying a trace amount of crude oil enters the oil-water separator 121 from the first connecting pipe 121A at the bottom of the oil-water separation tank 12, and the oil-water separation is completed through the oil-water separator 121. The oil-water separator 121 serves as the second barrier to prevent crude oil from entering the water tank. The crude oil separated by the oil-water separator 121 enters the oil tank 11 through the second connecting pipe 121B, and is returned to the oil tank 11 for storage through the circulating oil pump 141. The separated water enters the water tank 13 through the third connecting pipe 121C, and comes out from the top of the water tank 13. The oil and water are separated again by gravity. A dirty oil pipe 131 is installed on the top of the water tank, which is connected to the top of the water tank 13, and sucks the dirty oil and mixes into the second connecting pipe 121B, which acts as a third barrier to prevent the crude oil from being discharged into the water tank. The volume capacity of the water tank 13 can store ballast water used for crude oil loading and unloading. The water inlet pipe 133 and the water outlet pipe 132 are installed inside. The water discharged into the water tank by the third connecting pipe 121C is discharged from the water tank through the water outlet pipe 132 to achieve the pressure balance of the underwater oil storage.

[0061] When crude oil is unloaded, the unloading pump 142 is started, and the crude oil is transported out through the oil outlet pipe 112. At the same time, the water inlet pipe 133 is opened, and seawater enters the water tank 13 to increase the water pressure head. In order to achieve the pressure balance of underwater oil storage, seawater with a volume equal to the volume of the transported crude oil enters the water tank 13 through the water inlet pipe 133. The seawater in the water tank 13 enters the oil-water separator 121 through the third connecting pipe 121C, and enters the oil-water separation cabin 12 from the first connecting pipe 121A. The oil and water in the oil-water separation cabin 12 are squeezed into the bottom of the oil tank 11 from the connecting pipe 113, and continuously rise to replace the volume of the crude oil transported out. Finally, the crude oil in the oil tank is transported out through the oil outlet pipe 112.

[0062] The preferred specific embodiments of the utility model are described in detail above. It should be understood that ordinary technicians in this field can make many modifications and changes based on the concept of the utility model without creative work. Therefore, all technical solutions that can be obtained by technicians in this technical field based on the concept of the utility model through logical analysis, reasoning or limited experiments on the basis of the existing technology should be within the scope of protection determined by the claims.

Claims

1. An underwater oil storage system, characterized in that: Including oil tanks, oil-water separation tanks and water tanks located underwater; An oil inlet pipe is provided in the oil tank, and crude oil enters the oil tank through the oil inlet pipe; a connecting pipe is provided in the oil tank, a first connecting port of the connecting pipe is connected to the oil tank and is located at the bottom of the oil tank, and a second connecting port of the connecting pipe is connected to the oil-water separation cabin and is located at the top of the oil-water separation cabin, so as to transport the oil-water mixture located below the oil-water interface in the oil tank to the oil-water separation cabin; An oil-water separator and a first connecting pipe, a second connecting pipe and a third connecting pipe connected to the oil-water separator are arranged in the oil-water separation cabin. The external interface of the first connecting pipe is located at the bottom of the oil-water separation cabin to transport the oil-water mixture into the oil-water separator. The outlet of the second connecting pipe is connected to the oil tank to transport the oil separated by the oil-water separator into the oil tank. The external interface of the third connecting pipe is connected to the water tank to transport the water separated by the oil-water separator into the water tank.

2. The underwater oil storage system according to claim 1, characterized in that: It also includes a circulating oil pump, and the outlet of the second connecting pipe is connected to the oil inlet pipe through the circulating oil pump to transport the oil separated by the oil-water separator to the oil tank.

3. The underwater oil storage system according to claim 2, characterized in that: It also includes a dirty oil pipe, one interface of which is connected to the water tank and located at the top of the water tank, and the other interface of the dirty oil pipe is connected to the pipe section in the second connecting pipe located upstream of the circulating oil pump.

4. The underwater oil storage system according to claim 2, characterized in that: It also includes an emulsion inlet pipe and an emulsion outlet pipe, wherein the emulsion inlet pipe is connected to a pipe section in the second connecting pipe located upstream of the circulating oil pump, and the emulsion outlet pipe is connected to a pipe section in the second connecting pipe located downstream of the circulating oil pump.

5. The underwater oil storage system according to any one of claims 1 to 4, characterized in that: It also includes a chemical agent pipe, which is connected to the connecting pipe in the oil tank and the first connecting pipe in the oil-water separation cabin.

6. The underwater oil storage system according to any one of claims 1 to 4, characterized in that: The oil tank is also provided with an oil outlet pipe, and the outlet of the oil inlet pipe and the inlet of the oil outlet pipe are both multiple; The outlets of the plurality of oil inlet pipes and the inlets of the plurality of oil outlet pipes are evenly arranged in an annular shape along the side wall of the oil tank.

7. The underwater oil storage system according to claim 6, characterized in that: The oil outlet pipe is provided with an unloading pump, and the crude oil in the oil tank is transported to the outside through the oil outlet pipe and the unloading pump.

8. The underwater oil storage system according to any one of claims 1 to 4, characterized in that: It also includes a heating liquid supply pipe, a heating coil and a heating liquid return pipe; The heating coil is arranged in the oil tank, the inlet of the heating coil is connected to the heating liquid supply pipe, and the outlet of the heating coil is connected to the heating liquid return pipe.

9. The underwater oil storage system according to any one of claims 1 to 4, characterized in that: A water outlet pipe and a water inlet pipe are provided in the water tank; the inlet of the water outlet pipe and the outlet of the water inlet pipe are connected to the water tank, and the inlet of the water outlet pipe, the outlet of the water outlet pipe, the inlet of the water inlet pipe and the outlet of the water inlet pipe are all located at the bottom of the water tank.

10. The underwater oil storage system according to any one of claims 1 to 4, characterized in that: The oil tank, the oil-water separation tank and the water tank are arranged in parallel in the same direction; or, the oil tank and the water tank are arranged in parallel in the same direction, and the oil-water separation tank and the water tank are arranged in parallel in another direction.

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