Modular system for underwater exploitation and underwater storage of offshore oil and gas and construction method

Abstract

The invention discloses a modularized system for underwater exploitation and underwater storage of offshore oil and gas and a construction method, belongs to the technical field of offshore oil and gas storage and transportation, and aims to solve the problem that an existing offshore oil storage and drainage device is high in construction cost. The modularized system for underwater exploitation and underwater storage of the offshore oil and gas comprises an underwater exploitation module and an underwater storage module, the underwater storage module comprises an outer frame (1) and an oil storage bag (3), the outer frame (1) comprises a frame body (11) and a containing space (12), and the oil storage bag (3) is fixed in the containing space (12). The underwater storage module is built underwater, the cost of the outer frame and the oil storage bag is relatively low, meanwhile, safe storage and output of crude oil can be achieved, the oil field development problem is solved, the benefits of oil field development are guaranteed, and safe and efficient development of offshore oil is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of marine oil and gas storage and export, and specifically to a modular system for marine oil and gas underwater exploitation and storage, and also to a method for constructing the modular system for marine oil and gas underwater exploitation and storage. Background Art

[0002] In the process of offshore oilfield development, the storage and transportation of crude oil is an important link. The conventional storage and transportation modes are: 1. The well flow produced by the jacket wellhead platform is transported to the central production and processing platform through the submarine mixed pipeline for processing, and the finished oil is then transported to the land terminal through the submarine oil and gas pipelines respectively; 2. The well flow produced by the jacket wellhead platform is transported to the floating production storage and spillway unit (FPSO) through the submarine mixed pipeline for processing, and the finished oil is stored on the FPSO, and the oil is regularly unloaded by shuttle tankers and sent to the port. The conventional development model has a large investment in the initial stage of development, a long construction period, high operation and maintenance costs, and poor economic efficiency, especially in the development of small offshore oil fields and offshore marginal oil fields, the economic effect is extremely poor, and it is difficult to achieve profitability. Summary of the invention

[0003] In order to solve the problem of high construction cost of the above-mentioned existing offshore oil storage and drainage devices, the present invention provides a modular system for underwater exploitation and storage of marine oil and gas and a construction method thereof. The multi-chamber combined underwater oil storage bag device in the modular system for underwater exploitation and storage of marine oil and gas is built underwater, and the cost of the outer frame and the oil storage bag is relatively low. At the same time, it can realize the safe storage and external transportation of crude oil, so as to solve the problems of oil field development, reduce economic losses, ensure the benefits of oil field development, reduce operational risks, and realize safe and efficient development of marine oil.

[0004] The technical solution adopted by the embodiment of the present invention to solve the technical problem is:

[0005] A modular system for underwater exploitation and storage of marine oil and gas, comprising an underwater exploitation module and an underwater storage module; the underwater exploitation module contains an underwater wellhead device and an underwater separation device; the underwater storage module contains a multi-cavity combined underwater oil storage bag device, the multi-cavity combined underwater oil storage bag device comprises an outer frame and an oil storage bag, the outer frame contains a frame body and a containing space, the oil storage bag is fixed in the containing space, the oil storage bag contains a plurality of mutually independent bag chambers, the plurality of mutually independent bag chambers are arranged in a left-right direction, and adjacent bag chambers are isolated by partitions; the underwater wellhead device, the underwater separation device and the oil storage bag are connected in sequence.

[0006] The frame body comprises an upper frame, supporting columns and a lower frame which are connected in sequence from top to bottom. The accommodating space is cut into a trapezoidal cross section by a vertical section extending in the front-to-back direction, with the top of the trapezoid facing upward and the bottom facing downward. The lower frame can be connected and fixed to the seabed by a suction anchor.

[0007] The frame is a steel tube concrete structure, the upper frame contains multiple upper beams, the multiple upper beams are arranged at intervals along the front and rear directions, the upper beams extend along the left and right directions, the support columns are located around the frame, and the oil storage bag is a cubic structure.

[0008] A plurality of fixed flanges are fixed on the upper crossbeam, and the plurality of fixed flanges are arranged at intervals in the left-right direction. A plurality of flange seats are fixed on the upper surface of the oil storage bag, and the flange seats are connected and fixed correspondingly to the fixed flanges, and the upper crossbeam can bear the weight of the oil storage bag.

[0009] The front side, rear side, left side and right side of the oil storage bag are fixedly connected with fixed lifting rings, which are connected to the upper frame through fixed cable chains. The fixed cable chains can limit the horizontal movement of the oil storage bag relative to the frame.

[0010] The oil storage bag includes a bag shell, and the multiple independent bag chambers are all located in the bag shell. The material of the bag shell is a flexible material. The bag shell contains an oil-resistant layer, a pressure-resistant layer and a corrosion-resistant layer stacked in sequence from the inside to the outside; the material of the oil-resistant layer is fluororubber material, the material of the pressure-resistant layer is aramid fiber composite material, and the material of the corrosion-resistant layer is chlorosulfonated polyethylene rubber material.

[0011] The oil storage bag is connected with a plurality of oil inlets and a plurality of oil outlets, and the oil inlets and the oil outlets are connected with the bag chambers one by one, and each oil inlet is connected with a control valve.

[0012] The underwater wellhead device is connected to the underwater separation device through a first delivery pipeline, and the underwater separation device is connected to the inlet end of each control valve through a second delivery pipeline.

[0013] The modular system for underwater exploitation and storage of marine oil and gas also includes an external transmission module, which includes a buoy, a third transmission pipeline and an external transmission oil tanker. The buoy can float on the sea surface, and the buoy is located above the outer frame. The inlet end of the third transmission pipeline is connected to the oil outlet in a one-to-one correspondence, and the oil outlet is located at the upper end of the oil storage bag. The outlet end of the third transmission pipeline is connected to the buoy, and the buoy is connected to the outer frame through an anchor chain.

[0014] A method for constructing the above-mentioned modular system for underwater oil and gas production and storage comprises the following steps:

[0015] Installing underwater wellhead equipment and underwater separation equipment underwater;

[0016] Measure the direction of ocean currents on the seafloor;

[0017] Install the multi-chamber combined underwater oil storage bag device on the seabed, with the front side or the rear side of the outer frame facing the direction of the sea current;

[0018] The underwater wellhead device, the underwater separation device and the oil storage bag are connected in sequence.

[0019] The beneficial effects of the embodiments of the present invention are:

[0020] 1. Modularize the entire process of underwater oil and gas production, storage and transportation to realize the process-based operation of crude oil production, storage and transportation. At the same time, it can avoid the use of conventional new production and processing platforms or the use of FPSO to carry out crude oil storage operations, and realize underwater storage and transportation of produced crude oil.

[0021] 2. A multi-chamber combined underwater oil storage bag device is used to store crude oil on the seabed. The seabed environment is relatively stable, which can avoid severe sea conditions on the sea surface and maintain the continuous crude oil extraction and storage operations under strong wind, wave and sea ice conditions.

[0022] 3. The multi-chamber combined underwater oil storage bag device contains multiple independent multi-chamber structures. When a sub-chamber is damaged, the other undamaged sub-chambers can be used to continue the crude oil storage operation. At the same time, the oil inlet flow of the oil storage bag can be controlled by the control valve, which effectively reduces the environmental pollution and economic losses caused by the damage and leakage of the underwater oil storage bag, making the underwater exploitation, storage and external transportation of marine oil and gas safer and more efficient.

[0023] 4. The oil storage bag in the multi-chamber combined underwater oil storage bag device has good compatibility, and the storage capacity can be increased by connecting multiple oil storage bags, which is safer and more convenient. At the same time, each oil storage bag is equipped with a separate frame to ensure that each device can work independently or cooperate with each other. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The drawings in the specification, which constitute a part of this application, are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0025] Figure 1 It is a schematic diagram of the main view of the modular system for underwater exploitation and storage of marine oil and gas according to the present invention.

[0026] Figure 2 It is a right side schematic diagram of the multi-cavity combined underwater oil storage bag device of the present invention.

[0027] Figure 3 It is a structural diagram of an outer frame.

[0028] Figure 4 This is a schematic diagram showing the left cystic chamber in a full state.

[0029] Figure 5 This is a schematic diagram showing the left and middle chambers being full.

[0030] Figure 6 It is a schematic diagram showing that the left chamber, the middle chamber and the right chamber are all in a full state.

[0031] Figure 7 It is a schematic structural diagram of the multi-cavity combined underwater oil storage bag device of the present invention installed in offshore waters.

[0032] Figure 8 It is a schematic diagram of the working state of the multi-cavity combined underwater oil storage bag device of the present invention in offshore waters.

[0033] Fig. 9 It is a structural schematic diagram of the modular system combination connection for underwater exploitation and storage of marine oil and gas.

[0034] The following are the descriptions of the reference numerals:

[0035] 1. External frame; 2. Suction anchor; 3. Oil storage bag; 4. Underwater wellhead device; 5. Underwater separation device; 6. Float; 7. External oil tanker; 8. Seabed;

[0036] 11. Frame; 12. Accommodating space; 13. Fixing flange;

[0037] 21. Pumping hole;

[0038] 31. Chamber; 32. Interlayer; 33. Flange seat; 34. Fixed lifting ring; 35. Fixed cable chain; 36. Oil inlet; 37. Oil outlet; 38. Control valve;

[0039] 41. The first delivery pipeline;

[0040] 51. Second delivery pipeline;

[0041] 61. Anchor chain; 62. The third delivery pipeline;

[0042] 111, upper frame; 112, support column; 113, lower frame; 114, upper beam; 115, lower beam;

[0043] 311, left cystic chamber; 312, middle cystic chamber; 313, right cystic chamber. DETAILED DESCRIPTION

[0044] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0045] For the convenience of understanding and description, an absolute positional relationship is adopted in the following description of the present invention. Without special instructions, the orientation word "upper" herein represents Figure 1 the upper side direction in Figure 1 the lower side direction in Figure 1 the left side direction in Figure 1 the right side direction in Figure 1 the direction perpendicular to the Figure 1 paper surface and pointing to the inner side of the paper surface, and the orientation word "rear" represents the direction perpendicular to the

[0046] paper surface and pointing to the outer side of the paper surface. The present invention is described from the observation perspective of the reader or user, but the above orientation words should not be understood or interpreted as limiting the protection scope of the present invention. Regarding the dimensions and angles of the components therein, those skilled in the art can specifically determine them according to actual needs or through a limited number of tests.

[0046] As Figure 1 and Figure 2 shown, a modular system for underwater exploitation and underwater storage of offshore oil and gas according to an embodiment of the present invention includes an underwater exploitation module and an underwater storage module; the underwater exploitation module includes an underwater wellhead device 4 and an underwater separation device 5; the underwater storage module includes a multi-chamber combined underwater oil storage bladder device, and the multi-chamber combined underwater oil storage bladder device includes an outer frame 1 and an oil storage bladder 3. The outer frame 1 includes an external frame body 11 and an internal accommodation space 12. The oil storage bladder 3 is fixed in the accommodation space 12. The oil storage bladder 3 contains a plurality of mutually independent bladder chambers 31. The plurality of bladder chambers 31 are not communicated with each other, and the plurality of mutually independent bladder chambers 31 are arranged in the left-right direction, and adjacent bladder chambers 31 are isolated by a partition layer 32.

[0047] As Figures 1 to 3 shown, the frame body 11 includes an upper layer frame 111, a support column 112, and a lower layer frame 113 that are sequentially connected from top to bottom. The cross-section of the accommodation space 12 cut by a vertical section extending in the front-rear direction is a trapezoid, preferably an isosceles trapezoid. The top of the trapezoid faces upward and the bottom faces downward. The lower layer frame 113 can be connected and fixed to the seabed 8 through a suction anchor 2. The suction anchors 2 are respectively located in front of and behind the accommodation space 12. For example, suction anchors 2 are provided both in front of and behind the accommodation space 12.

[0048] Among them, Figure 1 the front view structure of the multi-chamber combined underwater oil storage bladder device of the multi-chamber combined underwater oil storage bladder device shown in Figure 2 the right view structure of the multi-chamber combined underwater oil storage bladder device of the multi-chamber combined underwater oil storage bladder device shown in

[0049] The frame 11 is a steel tube concrete frame structure, which improves strength and rigidity and is conducive to the installation of the suction anchor 2. The upper frame 111 is a rectangular structure, and the upper frame 111 contains a plurality of upper beams 114, which can be steel tube concrete beams, and the plurality of upper beams 114 are arranged at intervals along the front-to-back direction, and the upper beams 114 extend along the left-to-right direction, and the support columns 112 are located around the frame 11, and the oil storage bag 3 is a cubic structure.

[0050] like Figures 1 to 3 As shown, a plurality of fixing flanges 13 are fixed on the upper crossbeam 114, and the plurality of fixing flanges 13 are arranged at intervals in the left-right direction. A plurality of flange seats 33 are fixed on the upper surface of the oil storage bag 3, and the flange seats 33 are connected and fixed with the fixing flanges 13 in a one-to-one correspondence, thereby limiting the oil storage bag 3 in the accommodation space 12 of the outer frame 1. The upper crossbeam 114 can bear the weight of the oil storage bag 3, and the weight of the oil storage bag 3 and the crude oil stored therein are transferred to the upper crossbeam 114 through the flange seats 33 and the fixing flanges 13 in sequence.

[0051] The support column 112 is in an inclined state, and the support column 112 can be a steel tube concrete column. The upper ends of the four support columns 112 are connected and fixed to the four corners of the upper frame 111 one by one. The lower frame 113 is roughly a rectangular structure. The lower frame 113 contains multiple lower beams 115, which can be steel tube concrete beams. The multiple lower beams 115 are arranged at intervals in the left-right direction, and the lower beams 115 extend in the front-back direction.

[0052] Along the up and down direction, the front side, rear side, left side and right side of the oil storage bag 3 are fixedly connected to the middle outside with fixed rings 34, and the fixed rings 34 are connected to the upper frame 111 or the support column 112 through a fixed chain 35. The fixed chain 35 can limit the horizontal movement of the oil storage bag 3 relative to the frame 11, thereby ensuring that when the oil storage bag 3 is fully loaded, there is a gap between the bottom of the bag and the seabed mud to avoid wear of the bag.

[0053] The oil storage capsule 3 comprises a capsule shell (or also called a capsule body), the partition layer 32 and the multiple independent capsule chambers 31 are all located in the capsule shell, the capsule shell is made of flexible material, and the capsule shell comprises an oil-resistant layer, a pressure-resistant layer and a corrosion-resistant layer which are stacked in sequence from the inside to the outside.

[0054] The material of the oil-resistant layer is fluororubber (FKM), which has good tolerance to complex components of crude oil. Its advantages are: excellent chemical resistance and high temperature resistance, strong tolerance to crude oil and its complex additives and corrosive substances. In harsh environments with high temperature and high pressure, complex crude oil components and corrosive substances, it can strongly resist crude oil erosion and temperature shock, ensure oil storage safety and bladder life, and has significant advantages in oil storage facilities under harsh working conditions of large offshore oil fields.

[0055] The material of the pressure-resistant layer is aramid fiber composite material, which has high strength, light weight, high modulus, and excellent fatigue and impact resistance. Its advantages are: greatly enhancing the pressure resistance of the oil storage bladder, its excellent fatigue resistance and impact resistance, reliably maintaining the stability of the bladder in the complex marine environment of deep sea high pressure and frequent external force impact, building a key defense line for oil storage safety, and being indispensable in deep sea oil fields or oil storage facilities in areas with harsh sea conditions, which can effectively reduce the risk of oil storage bladder failure caused by environmental factors and extend the maintenance cycle.

[0056] The material of the corrosion-resistant layer is chlorosulfonated polyethylene rubber (CSM), which contains molecular chlorine and sulfonyl chloride groups and has good corrosion resistance and aging resistance. Its advantages are: it can fully resist the erosion of seawater salinity, microorganisms and atmospheric corrosive media in the marine environment, and its aging resistance ensures that the corrosion resistance of the oil storage bladder is stable during long-term use, and the bladder shell has a long-lasting protective effect. It is widely used in offshore or shallow sea oil storage bladders, economical and practical, and can significantly extend the service life of the oil storage bladder at a reasonable cost, reducing maintenance costs and replacement frequency.

[0057] Preferably, the oil storage bag 3 contains three chambers 31, which are respectively a left chamber 311, a middle chamber 312 and a right chamber 313. The three chambers 31 are used to store crude oil from the branch pipeline, and the chambers are independent and do not interfere with each other. The three chambers 31 are used in conjunction with the following control valve 38 to ensure that the oil storage and external transmission operations continue when a chamber leaks. Figures 4 to 6 shown.

[0058] The oil storage bag 3 is connected to multiple oil inlets 36 and multiple oil outlets 37, and the oil inlets 36 and the oil outlets 37 are connected to the bag chambers 31 one-to-one, that is, the bag chambers 31 are connected to their own independent oil inlets 36 and oil outlets 37, and the oil inlet and oil outlet of each bag chamber 31 do not affect each other. Each oil inlet 36 is connected to the outside of the control valve 38, that is, the control valve 38 corresponds to the bag chamber 31 one-to-one, and the stored oil can be distributed through the control valve 38.

[0059] The lower end surface of the oil storage bag 3 is higher than the lower end surface of the outer frame 1, and there is a gap between the lower end surface of the oil storage bag 3 and the surface of the seabed 8. The underwater wellhead device 4 is connected to the underwater separation device 5 through the first transmission pipeline 41, and the underwater separation device 5 is connected to the inlet end of each control valve 38 through the second transmission pipeline 51.

[0060] The underwater mining module extracts crude oil from the bottom of the well to the wellhead, and performs oil (or gas) and water separation to obtain crude oil (natural gas) with higher purity. It is composed of an underwater wellhead device 4 and an underwater separation device 5. The underwater wellhead device 4 is used to control and regulate the production of the oil well, and transport the reservoir fluid to the underwater separation device 5 through a first transmission pipeline 41. The underwater separation device 5 receives the mixed fluid from the submarine pipeline, performs oil (or gas) and water separation processing on it, and obtains high-purity crude oil.

[0061] Specifically, the underwater wellhead device 4 and the underwater separation device 5 can both adopt existing technologies. The underwater wellhead device 4 mainly includes an oil production tree and an underwater manifold. The first delivery pipeline 41 of the underwater manifold is connected to the underwater separation device 5. The underwater wellhead device 4 and the first delivery pipeline 41 deliver the produced oil and gas to the underwater separation device 5. The underwater separation device 5 can separate the produced oil and gas resources, and the separated crude oil or natural gas can be delivered to the oil storage bag 3 through the second delivery pipeline 51 for storage.

[0062] like Figure 1 to Figure 2 As shown, the modular system for underwater exploitation and storage of marine oil and gas also includes an external transmission module, which includes a buoy 6, a third transmission pipeline 62 and an external transmission tanker 7. The buoy 6 can float on the sea surface, and the buoy 6 is located above the outer frame 1. There are multiple third transmission pipelines 62, and the inlet ends of the third transmission pipelines 62 are connected to the oil outlets 37 one by one. The outlet end of the third transmission pipeline 62 is connected to the buoy 6, and the buoy 6 is connected to the upper part of the outer frame 1 through an anchor chain 61. The buoy 6 is moored on the sea surface through the anchor chain 61. The external transmission tanker 7 extracts crude oil (or natural gas) from the underwater oil storage bag through the third transmission pipeline 62 and transports it back to land.

[0063] The oil outlet 37 is located at the upper end of the oil storage capsule 3, and the oil outlets 37 of the left capsule chamber 311, the middle capsule chamber 312 and the right capsule chamber 313 are all located at the upper end. Based on the principle of oil-water density difference, oil and water form an oil-water interface after standing for a long time, and the oil will float above the water. The oil delivery pipe is connected to the oil delivery port for external delivery, which can reduce the water content of the externally delivered oil.

[0064] The advantages of the present invention are: the entire process of underwater exploitation, underwater storage and external transmission of marine oil and gas is modularized, and an underwater oil storage method is introduced. The basic principle of the method is to use the flexible characteristics of the underwater oil storage bag to achieve rapid and efficient collection and storage of seabed oil and gas under complex underwater geological conditions. Compared with traditional oil and gas storage methods, this method has the advantages of small size, light weight, simple structure, etc., can better meet the needs of underwater oil production operations, reduce production costs, ensure the benefits of oil field development, reduce development risks, and achieve efficient development of marine oil fields.

[0065] The following is a method for constructing the modular system for underwater oil and gas production and storage. The method for constructing the modular system for underwater oil and gas production and storage comprises the following steps:

[0066] Installing an underwater wellhead device 4 and an underwater separation device 5 underwater;

[0067] Measure the direction of the sea current on the seabed 8, for example, the direction of the sea current is direction A or direction B, such as Figure 2 As shown;

[0068] The connected outer frame 1 and the oil storage bag 3 are hoisted as a whole, and are placed on the seabed 8 by their own gravity. The multi-cavity combined underwater oil storage bag device is installed on the seabed 8. During installation, the front side or rear side of the outer frame 1 is ensured to face the sea current direction A or B, and the outer frame 1 is connected and fixed to the seabed 8 by the suction anchor 2; the front side or rear side of the outer frame 1 faces the sea current direction A or B, which can avoid vortex-induced vibration fatigue damage, and the cross-section of the accommodating space 12 after being cut by the vertical section extending in the front-to-back direction is trapezoidal, which not only ensures the bottom-sitting stability of the frame, but also facilitates the connection of the fixing flange;

[0069] The specific installation method of the suction anchor 2 is to pump out the seawater in the anchor barrel of the suction anchor 2 through the pumping hole 21, so that low pressure is formed inside the anchor barrel, and the suction anchor 2 is inserted into the seabed soil by using high-pressure seawater, thereby fixing the outer frame 1. After the outer frame 1 is fixed, the underwater wellhead device 4, the underwater separation device 5 and the oil storage bag 3 are connected in sequence, the underwater wellhead device 4 is connected to the underwater separation device 5 through the first delivery pipeline 41, and the underwater separation device 5 is connected to each control valve 38 of the oil storage bag 3 through the second delivery pipeline 51. When the pipeline of the underwater oil production equipment is connected to the delivery pipeline, that is, when the oil delivery pipeline is connected to the oil storage bag 3, the oil storage operation can be carried out.

[0070] When in use, crude oil is input into the chamber 31 of the required oil storage bag 3 through the second delivery pipeline 51 and the control valve 38, the volume of the oil storage bag 3 will increase, and the oil storage bag 3 will store crude oil; when the underwater oil storage bag 3 reaches a full state, the control valve 38 is closed to prevent the oil inlet 36 from continuing to enter the oil and causing leakage. In addition, when the bag body is partially damaged, it only needs to adjust the state of the control valve 38 to stop injecting oil and gas into the damaged sub-capsule chamber, and the oil storage operation can continue through other sub-capsule chambers.

[0071] During the export operation stage, the relevant equipment on the export tanker 7 is connected to the outlet end of the third transmission pipeline 62 connected to the capsule chamber 31 of the required oil storage bag 3, and the crude oil in the capsule chamber 31 of the required oil storage bag 3 is exported to the export tanker 7, and then the export tanker 7 completes the transportation of marine oil and gas resources.

[0072] When in use, when performing oil storage operations, the oil flow rate of the oil production equipment can be distributed by controlling the control valve 38 on the second delivery pipeline 51, and the flow rate can be distributed to the three chambers of the left chamber 311, the middle chamber 312 and the right chamber 313 respectively.

[0073] When the oil storage volume reaches the condition for external transmission, the external transmission oil tanker 7 is close to the floating ball 6, and the third transmission pipeline 62 corresponding to the capsule chamber for pre-transporting oil is connected, so that the oil stored in the capsule chamber can be transported to the external transmission oil tanker 7 for external transmission. When the capsule body is partially damaged, after it is determined that one / two capsule chambers of the left capsule chamber 311, the middle capsule chamber 312 and the right capsule chamber 313 are leaking, the control valve 38 corresponding to the leaking capsule chamber can be controlled to continue to use the other two / one capsule chambers for oil storage without stopping the oil production operation. The operation process can be remotely controlled and monitored, which improves the safety and reliability of oil production and the environmental conditions of the workers.

[0074] The modular system for underwater oil and gas production and storage can be applied not only to offshore areas but also to offshore areas, such as Figure 7 and Figure 8 Of course, for nearshore oil fields, the export module can be optimized. Under nearshore conditions, the third transmission pipeline 62 can be directly connected to the onshore equipment to avoid the use of the buoy 6, the mooring anchor chain 61 and the export tanker 7, further saving the mining cost.

[0075] Of course, for shallow water oil fields, the fixing method of the suction anchor 2 can be adjusted to pile-type fixing. Under this condition, the corresponding external transmission mode can also be optimized. The connection between the underwater storage module and the underwater mining module can be disconnected by an underwater frogman, and the piles can be pulled out by a crane, and the underwater oil storage bag 3 can be directly lifted onto the tugboat to achieve the transportation purpose. This method simplifies the equipment involved in the external transmission module and the connection between modules, and can effectively improve the working efficiency.

[0076] When large-volume underwater oil storage is performed in an oil field, a plurality of the modular systems for underwater production and storage of marine oil and gas can be installed, and the single multi-chamber combined underwater oil storage bag device can be expanded into a plurality of multi-chamber combined underwater oil storage bag devices by connecting the oil production equipment to the oil inlet connection end of the respective second transmission pipelines 51, thereby realizing large-volume oil storage in an oil field, such as Fig. 9 shown.

[0077] The modular system for underwater oil and gas exploitation and storage can complete the underwater storage and export operations after the exploitation of marine oil and gas. Its advantages are that underwater oil storage is not affected by floating ice, strong winds and huge waves on the sea surface, and can be continuously produced even in severe sea conditions; it is isolated from fire sources and lightning, and oil and gas are not easily ignited, and there is no need to set up an inert gas system; the oil storage bag is installed on the seabed, and the probability of being hit by ships and other objects is greatly reduced. The underwater oil storage bag has low construction cost, high efficiency, and good economy, which can significantly reduce the daily operation and maintenance costs of oil fields and improve the safety of the operation links.

[0078] The present invention is used for the exploitation, storage and export of marine oil and gas resources. The entire process of underwater exploitation, underwater storage and export of marine oil and gas is modularized, and can realize the rapid and efficient collection and storage of seabed oil and gas under complex underwater environmental conditions. Compared with the traditional oil and gas storage method, this method has the advantages of small size, light weight, simple structure, etc., can better meet the needs of underwater oil production operations, and avoid the construction of new production and processing platforms to exploit marine oil and gas fields. It can continue to carry out exploitation and storage operations under harsh sea conditions, improve the working environment of workers, avoid the occurrence of high-risk leakage, reduce production costs while ensuring safe development, ensure the benefits of oil field development, and is conducive to the efficient development of marine oil fields. It has good practicality and promotion value.

[0079] The above is only a specific embodiment of the present invention, and cannot be used to limit the scope of the invention. Therefore, the replacement of equivalent components, or equivalent changes and modifications made according to the protection scope of the present invention should still fall within the scope of the present invention. In addition, the technical features of the present invention can be freely combined with each other, with technical features and technical solutions, with technical solutions and embodiments.

Claims

1. A modular system for underwater production and storage of marine oil and gas, characterized in that: The modular system for underwater exploitation and storage of marine oil and gas comprises an underwater exploitation module and an underwater storage module; The underwater mining module comprises an underwater wellhead device (4) and an underwater separation device (5); The underwater storage module comprises a multi-cavity combined underwater oil storage bag device, the multi-cavity combined underwater oil storage bag device comprises an outer frame (1) and an oil storage bag (3), the outer frame (1) comprises a frame body (11) and a receiving space (12), the oil storage bag (3) is fixed in the receiving space (12), the oil storage bag (3) comprises a plurality of mutually independent bag chambers (31), the plurality of mutually independent bag chambers (31) are arranged in a left-right direction, and adjacent bag chambers (31) are isolated by a partition (32); the underwater wellhead device (4), the underwater separation device (5) and the oil storage bag (3) are connected in sequence.

2. The modular system for underwater production and storage of marine oil and gas according to claim 1, characterized in that: The frame (11) comprises an upper frame (111), a support column (112) and a lower frame (113) which are connected in sequence from top to bottom. The cross section of the accommodating space (12) is a trapezoid after being cut by a vertical section extending in the front-to-back direction. The top end of the trapezoid faces upward and the bottom end faces downward. The lower frame (113) can be connected and fixed to the seabed (8) by a suction anchor (2).

3. The modular system for underwater production and storage of marine oil and gas according to claim 2 is characterized in that: The frame (11) is a steel tube concrete structure. The upper frame (111) contains a plurality of upper cross beams (114). The plurality of upper cross beams (114) are arranged at intervals along the front-rear direction. The upper cross beams (114) extend along the left-right direction. The support columns (112) are located around the frame (11). The oil storage bag (3) is a cubic structure.

4. The modular system for underwater production and storage of marine oil and gas according to claim 3 is characterized in that: A plurality of fixing flanges (13) are fixed on the upper crossbeam (114), and the plurality of fixing flanges (13) are arranged at intervals in the left-right direction. A plurality of flange seats (33) are fixed on the upper surface of the oil storage bag (3), and the flange seats (33) are correspondingly connected and fixed to the fixing flanges (13). The upper crossbeam (114) can bear the weight of the oil storage bag (3).

5. The modular system for underwater production and storage of marine oil and gas according to claim 3 is characterized in that: The front side, rear side, left side and right side of the oil storage bag (3) are all fixedly connected to the outside with fixed lifting rings (34), and the fixed lifting rings (14) are connected to the upper frame (111) through fixed chains (35). The fixed chains (35) can limit the movement of the oil storage bag (3) in the horizontal direction relative to the frame (11).

6. The modular system for underwater production and storage of marine oil and gas according to claim 1, characterized in that: The oil storage capsule (3) comprises a capsule shell, wherein the plurality of mutually independent capsule chambers (31) are all located in the capsule shell, wherein the capsule shell is made of a flexible material, wherein the capsule shell comprises an oil-resistant layer, a pressure-resistant layer and a corrosion-resistant layer which are sequentially stacked from the inside to the outside, wherein the oil-resistant layer is made of a fluororubber material, the pressure-resistant layer is made of an aramid fiber composite material, and the corrosion-resistant layer is made of a chlorosulfonated polyethylene rubber material.

7. The modular system for underwater production and storage of marine oil and gas according to claim 1, characterized in that: The oil storage bag (3) is connected to a plurality of oil inlets (36) and a plurality of oil outlets (37), the oil inlets (36) and the oil outlets (37) are connected to the bag chamber (31) in a one-to-one correspondence, and each oil inlet (36) is connected to a control valve (38).

8. The modular system for underwater production and storage of marine oil and gas according to claim 7, characterized in that: The underwater wellhead device (4) is connected to the underwater separation device (5) via a first delivery pipeline (41), and the underwater separation device (5) is connected to the inlet end of each control valve (38) via a second delivery pipeline (51).

9. The modular system for underwater production and storage of marine oil and gas according to claim 7, characterized in that: The modular system for underwater exploitation and storage of marine oil and gas also includes an external transmission module, which includes a buoy (6), a third transmission pipeline (62) and an external transmission tanker (7). The buoy (6) is capable of floating on the sea surface. The buoy (6) is located above the outer frame (1). The inlet end of the third transmission pipeline (62) is connected to the oil outlet (37) in a one-to-one correspondence. The oil outlet (37) is located at the upper end of the oil storage bag (3). The outlet end of the third transmission pipeline (62) is connected to the buoy (6). The buoy (6) is connected to the outer frame (1) via an anchor chain (61).

10. A method for constructing a modular system for underwater oil and gas production and storage according to claim 2, characterized in that: The method for constructing a modular system for underwater oil and gas production and storage comprises the following steps: Installing an underwater wellhead device (4) and an underwater separation device (5) underwater; Measure the direction of ocean currents on the seafloor; The multi-chamber combined underwater oil storage bag device is installed on the seabed, with the front side or the rear side of the outer frame (1) facing the direction of the sea current; The underwater wellhead device (4), the underwater separation device (5) and the oil storage bag (3) are connected in sequence.

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