Concealed underwater production facility suitable for limited sea area and use method of concealed underwater production facility

Abstract

The invention discloses a concealed underwater production facility suitable for a restricted sea area and a use method thereof. The concealed underwater production facility comprises a mud surface lower box body, the mud surface lower box body comprises a top cover and a base, a side wall is arranged between the top cover and the base, and the top cover, the base and the side wall jointly define a containing cavity; an underwater production assembly is arranged in the containing cavity and comprises a well drilling guide pipe and a Christmas tree, and the Christmas tree is fixed to a well head in the well drilling guide pipe. The underwater production assembly and the integrated supporting structure are fixed to the mud surface lower box body capable of isolating silt and muddy water after being skid-mounted, so that the underwater production facility formed by integrating and skid-mounting the mud surface lower box body and the underwater production assembly structurally forms a skid-mounted assembly, and the skid-mounted assembly can be arranged in a mud surface lower foundation pit for production; therefore, the influence on normal navigation in a shallow water military sensitive area and a maritime navigation sensitive area is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of offshore oil and gas engineering, and particularly relates to a concealed underwater production facility applicable to restricted sea areas and a method for using the same. Background Art

[0002] An underwater production facility refers to a production facility that uses underwater completion technology in combination with facilities such as fixed platforms and floating production platforms to form different offshore oilfield development forms. It is one of the key technologies for offshore oilfield development. The underwater production facility mainly includes key equipment such as wellheads, subsea christmas trees, pipelines, and control systems, and can be installed and operated on different platforms or facilities.

[0003] Among the offshore oil and gas resources in China's sea areas, military-sensitive areas and maritime navigation-sensitive areas account for a relatively large proportion. Maritime navigation-sensitive areas and military-sensitive areas belong to shallow water areas. For shallow waters, the traditional approach is to use fixed jacket platforms and build oil production equipment on the platforms for easy operation and adjustment. However, for the shallow water areas of military-sensitive areas and maritime navigation-sensitive areas, using fixed jacket platforms or subsea production facilities on the mud surface will occupy the space of the navigation area, thus affecting the normal navigation of military-sensitive areas and maritime navigation-sensitive areas. Summary of the Invention

[0004] In order to solve the above technical problems, the present invention provides a concealed underwater production facility applicable to restricted sea areas and a method for using the same.

[0005] In a first aspect, the present invention provides a concealed underwater production facility applicable to restricted sea areas, which is achieved by adopting the following technical solutions.

[0006] A concealed underwater production facility applicable to restricted sea areas includes a subsea box body. The subsea box body includes a top cover and a base, and a side wall is provided between the top cover and the base. The top cover, the base, and the side wall jointly enclose a receiving cavity. An underwater production assembly is provided in the receiving cavity. The underwater production assembly includes a drilling conductor and a christmas tree, and the christmas tree is fixed to the wellhead inside the drilling conductor.

[0007] Furthermore, an integrated support structure is provided between the top cover and the base of the subsea box body. The integrated support structure is connected to the base and the side wall to form a structural whole, and the underwater production assembly is integrated with the integrated support structure into a skid.

[0008] Even further, the integrated support structure has a first surface facing the top cover, and an opening is formed in the middle of the first surface. Along the vertical direction, a part of the christmas tree passes through the opening. The first surface, the side wall, and the top cover jointly enclose a diver passage, and the diver passage surrounds the opening.

[0009] Further, the top cover includes a top cover body, on which a diver inlet and an equipment inlet are provided. A first cover member is provided on the diver inlet, and a second cover member is provided on the equipment inlet. In the vertical direction, the projection of the equipment inlet on the first surface overlaps at least part of the opening, and the projection of the diver inlet on the first surface overlaps at least part of the diver passage.

[0010] Further, the subsea production assembly further includes a subsea distribution unit, a pipeline assembly, and a flying lead assembly. The subsea distribution unit is connected to the pipeline assembly and the christmas tree through the flying lead assembly, and the pipeline assembly is connected to the christmas tree. The subsea distribution unit is fixed on the upper surface of the integrated support structure, and at least part of the pipeline assembly and the flying lead assembly are fixed on the base and / or the side of the integrated support structure away from the subsea distribution unit.

[0011] Furthermore, the subsea distribution unit includes an umbilical termination, a subsea routing module, and a subsea control module. The umbilical termination is connected to the christmas tree through the subsea routing module and the subsea control module.

[0012] Furthermore, the pipeline assembly includes a subsea pipeline, a flowmeter, an underwater valve, and a christmas tree jumper. The subsea pipeline is connected to the christmas tree through the christmas tree jumper. The subsea pipeline and / or the christmas tree jumper are provided with a flowmeter and an underwater valve.

[0013] Further, the concealed subsea production facility further includes a protection structure located outside the box body below the mud line. The protection structure is an inclined protection wall, and both sides of the protection wall are respectively connected to the top cover and the base. The projected area of the base is larger than that of the top cover. The angle between the surface of the protection structure and the vertical direction is an acute angle. The base is a hollow structure; and / or, the protection structure is provided with mesh holes.

[0014] Further, the concealed subsea production facility further includes at least one of driven piles, suction piles, and anti-settlement plates provided at the bottom of the base.

[0015] In a second aspect, the present invention provides a method for using a concealed subsea production facility applicable to restricted area waters, which is realized by adopting the following technical solutions.

[0016] A method for using the above-mentioned concealed subsea production facility applicable to restricted area waters includes

[0017] Integrating at least part of the subsea production assembly on the integrated support structure of the box body below the mud line to form an integrated skid-mounted subsea production assembly;

[0018] Assembling the top cover, the base, the side wall, and the integrated support structure integrally provided with at least part of the subsea production assembly to obtain a concealed subsea production facility;

[0019] Set up a foundation pit on the underwater mud surface;

[0020] Lower the concealed underwater production facility into the foundation pit on the underwater mud surface.

[0021] The present application has the following beneficial effects.

[0022] In the present invention, by arranging the underwater production components in the box body under the mud surface, the box body under the mud surface can isolate sediment and turbid water, enabling the entire underwater production facility to operate in the foundation pit under the mud surface, so that the top of the entire underwater production facility can be lower than the underwater mud surface, reducing the possibility of the entire underwater production facility protruding above the water surface, thereby reducing the possibility of the entire underwater production facility occupying the space in the navigation channel area and minimizing the impact on the normal navigation in military-sensitive areas and maritime navigation-sensitive areas. In addition, before the entire concealed underwater production facility is lowered underwater, the drilling conduit and other equipment of the underwater production components can be first installed on the integrated support structure of the box body under the mud surface for integration, and then lowered underwater together with the box body under the mud surface, instead of first lowering the box body under the mud surface to the water surface and then using lifting equipment to lower the drilling conduit and other equipment of the underwater production components into the box body under the mud surface at the water surface for installation, thus reducing the installation cost of the underwater production facility. Description of the Drawings

[0023] Figure 1 is the structural schematic diagram of the present invention;

[0024] Figure 2 is the structural schematic diagram of the box body under the mud surface of the present invention;

[0025] Figure 3 is the schematic diagram of the integrated arrangement of the underwater production components on the integrated support structure of the present invention;

[0026] Figure 4 is the structural schematic diagram of the present invention placed in the foundation pit below the seabed mud surface;

[0027] Figure 5 is the side view of the present invention placed in the foundation pit below the seabed mud surface;

[0028] Figure 6 is the structural schematic diagram of the present invention (the area of the base is larger than the area of the top cover);

[0029] Figure 7 is the structural schematic diagram of the present invention with the top cover and part of the side wall removed;

[0030] Figure 8 is the top view of the present invention with the top cover removed;

[0031] Figure 9 is the top view of the present invention with the top cover, side wall and integrated support structure removed;

[0032] Figure 10 It is a schematic structural diagram after the installation of the protection structure of the present invention.

[0033] Among them, 100 is a concealed underwater production facility; 10 is a foundation pit; 20 is the mud surface; X is the vertical direction;

[0034] 1 is a sub-mud surface box; 11 is a top cover; 111 is a top cover main body; 112 is a first cover member; 113 is a second cover member; 12 is a base; 13 is a side wall; 14 is an integrated support structure; 141 is a first surface; 14a is an opening; 14b is a diver passage; 15 is a support member; 1a is a receiving cavity; 1b is a first space; 1c is a second space;

[0035] 2 is an underwater production assembly; 21 is a Christmas tree;

[0036] 3 is an underwater distribution unit; 31 is an underwater control module; 32 is an underwater routing module; 33 is a umbilical cable terminal; 34 is an umbilical cable;

[0037] 4 is a pipeline assembly; 41 is a subsea pipeline; 42 is a flowmeter; 43 is an underwater valve; 44 is a Christmas tree jumper;

[0038] 5 is a protection structure;

[0039] 6 is a sinker plate. Detailed implementation manners

[0040] The following further describes this patent application in conjunction with embodiments.

[0041] As Figures 1-10 shown, a concealed underwater production facility applicable to restricted area waters includes a sub-mud surface box 1 and an underwater production assembly 2. The sub-mud surface box 1 includes a top cover 11, a base 12 and a side wall 13. The top cover 11 is arranged on one side of the side wall 13, the base 12 is arranged on the other side of the side wall 13, and the top cover 11, the base 12 and the side wall 13 jointly enclose a receiving cavity 1a. The underwater production assembly 2 is arranged in the receiving cavity 1a. The underwater production assembly 2 includes a drilling riser and a Christmas tree 21. The drilling riser is fixed to the integrated support structure 14, and the drilling riser passes through the base 12 to drill the oil field so that the subsequent Christmas tree 21 can extract oil and gas. The Christmas tree 21 is detachably fixed to the wellhead (not shown) inside the drilling riser. The Christmas tree 21 is connected to the wellhead, the later-installed Christmas tree jumper 44 and the pre-installed or later-installed flying wire.

[0042] In this application, by arranging the subsea production assembly 2 inside the subsea floor box 1, the subsea floor box 1 can isolate sediment and turbid water, enabling the entire concealed subsea production facility 100 to be installed in the foundation pit 10 below the seabed surface 20 for operation, so that the top of the entire concealed subsea production facility 100 can be lower than the subsea mud surface 20, reducing the possibility of the entire concealed subsea production facility 100 protruding above the water surface, thereby reducing the possibility of the entire concealed subsea production facility 100 occupying the space in the navigation channel area and minimizing the impact on the normal navigation in military-sensitive areas and maritime navigation-sensitive areas. It can be understood that the subsea floor system can also be installed on the seabed surface or partially below the seabed surface. Therefore, the concealed subsea production facility 100 of this application can also be installed on the seabed surface or partially below the seabed surface.

[0043] In some embodiments, the subsea floor box 1 includes an integrated support structure 14, which is arranged between the top cover 11 and the base 12, and the subsea production assembly 2 is integrally arranged on the integrated support structure 14. The integrated support structure 14 is connected to the base 12 and the side wall 13 to form a structural whole; at the same time, the subsea production assembly 2 and the integrated support structure 14 are integrated into a skid. Preferably, the integrated support structure 14 can adopt a grid plate. While improving the bearing performance, sediment and other impurities entering the subsea floor box 1 can flow through the grid holes of the grid plate to the lower part of the grid plate, reducing the impact of sediment and other impurities on the equipment above the integrated support structure 14. The integrated support structure 14 is provided with an opening 14a, and at least part of the Christmas tree 21 passes through the opening 14a along the vertical direction X, that is, at least part of the Christmas tree 21 is located above the integrated support structure 14, making it more convenient for divers to install and repair the Christmas tree 21 when they move on the integrated support structure 14.

[0044] In some embodiments, the subsea floor box 1 includes a support member 15, and the top cover 11, the base 12, the side wall 13 and the integrated support structure 14 are all fixed to the support member 15. The support member 15 is used as the core support structure of the concealed subsea production facility 100. The support member 15 can be cylindrical, strip-shaped or other shapes. Preferably, the number of support members 15 is four, and the four support members 15 are respectively located at the four corners of the base 12 to improve the stability of the entire concealed subsea production facility 100. The above-mentioned integrated support structure 14 is pre-fixed to the support member 15.

[0045] In some embodiments, along the vertical direction X, the integrated support structure 14 divides the accommodation cavity 1a to form a first space 1b and a second space 1c; the base 12, the side wall 13 and the integrated support structure 14 jointly enclose the first space 1b, and the integrated support structure 14, the side wall 13 and the top cover 11 jointly enclose the second space 1c, and at least part of the Christmas tree 21 is located in the second space 1c. The subsea production assembly 2 includes a subsea distribution unit 3, a pipeline assembly 4 and a flying lead assembly. The subsea distribution unit 3 is pre-fixed to the integrated support structure 14, at least part of the pipeline assembly 4 is pre-fixed to the base 12 and / or the integrated support structure 14, at least part of the flying lead assembly is pre-fixed to the base 12 and / or the integrated support structure 14. The subsea distribution unit 3 is located in the second space 1c, at least part of the pipeline assembly 4 is located in the first space 1b, and at least part of the flying lead assembly is located in the first space 1b.

[0046] Since at least part of the Christmas tree 21 is located in the second space 1c, the subsea distribution unit 3 is located in the second space 1c, at least part of the pipeline assembly 4 is located in the first space 1b, and at least part of the flying lead assembly is located in the first space 1b, the pipeline assembly 4 and the flying lead assembly located in the first space 1b cause less interference (such as electromagnetic interference, mechanical vibration interference, temperature interference, signal interference, etc.) to the subsea distribution unit 3 and the Christmas tree 21 located in the second space 1c, improving the stability and reliability of the entire concealed subsea production facility 100, and also making the layout of the entire concealed subsea production facility 100 modular, facilitating installation, disassembly and maintenance. In addition, the first space 1b located under the lower layer of the subsea housing 1 can also be used to accommodate sediment impurities entering the subsea housing 1, so as to reduce the occupation of the second space 1c by sediment impurities and thus affect the normal operation of the Christmas tree 21 and the subsea distribution unit 3.

[0047] In some embodiments, the integrated support structure 14 has a first surface 141 facing the top cover 11, an opening 14a is located in the middle of the first surface 141, and the periphery of the first surface 141, the side wall 13 and the top cover 11 jointly enclose a diver passage 14b, and the diver passage 14b is used as the activity space for divers. The diver passage 14b surrounds the opening 14a to facilitate the installation and maintenance of the equipment at the opening 14a in the middle of the first surface 141 by divers.

[0048] In some embodiments, the top cover 11 is detachably disposed on the side wall 13, and the top cover 11 can be removed or covered as a whole. The top cover 11 includes a top cover body 111, a first cover member 112 and a second cover member 113. The top cover body 111 is provided with a diver inlet and an equipment inlet. The first cover member 112 covers the diver inlet, and the second cover member 113 covers the equipment inlet. The diver inlet is used for divers to enter and exit the subsea box 1, and the equipment inlet is used for components and / or equipment of the subsea production facility 100 to enter and exit the subsea box 1. Along the vertical direction X, the projection of the equipment inlet on the first surface 141 overlaps at least partially with the opening 14a, so as to facilitate equipment such as the subsea production component 2, the subsea distribution unit 3, the pipeline component 4 and the flying lead component to enter the subsea box 1 through the equipment inlet and be installed near the opening 14a, and to facilitate the equipment near the opening 14a to be taken out of the subsea box 1 through the equipment inlet. The projection of the diver inlet on the first surface 141 overlaps at least partially with the diver passage 14b, so as to facilitate divers to enter the subsea box 1 through the diver inlet and descend to the diver passage 14b, and to facilitate the divers located in the diver passage 14b to rise to the diver inlet and exit the subsea box 1.

[0049] In some embodiments, the subsea distribution unit 3 includes an umbilical termination 33, a subsea routing module 32 and a subsea control module 31. The umbilical termination 33 is connected to the Christmas tree 21 and other equipment through the subsea routing module 32 and the subsea control module 31 to transmit power, communication signals, hydraulic oil and chemical agents to the Christmas tree 21 and other equipment. The umbilical termination 33, the subsea routing module 32 and the subsea control module 31 are all located in the second space 1c, so that the pipeline component 4 and the flying lead component partially located in the first space 1b have less interference with the umbilical termination 33, the subsea routing module 32, the subsea control module 31 and part of the Christmas tree 21 located in the second space 1c. Preferably, the umbilical termination 33, the subsea routing module 32 and the subsea control module 31 are pre-fixed to the integrated support structure 14.

[0050] In some embodiments, the pipeline assembly 4 includes a subsea pipeline 41, a flowmeter 42, an underwater valve 43, and a production tree jumper 44. The subsea pipeline 41 is connected to the production tree 21 through the production tree jumper 44. The subsea pipeline 41 and / or the production tree jumper 44 are provided with a flowmeter 42 and an underwater valve 43. At least a part of the subsea pipeline 41 is located in the first space 1b, at least a part of the flowmeter 42 is located in the first space 1b, at least a part of the underwater valve 43 is located in the first space 1b, and at least a part of the production tree jumper 44 is located in the first space 1b. In this way, the subsea pipeline 41, the flowmeter 42, the underwater valve 43, and the production tree jumper 44 partially located in the first space 1b cause less interference to the umbilical cable terminal 33, the underwater routing module 32, the underwater control module 31, and the production tree 21 located in the second space 1c. The valve is used to open, close, and adjust the flow rate of the subsea pipeline 41 and / or the production tree jumper 44. The flowmeter 42 is used to measure the flow rate of the oil and gas in the subsea pipeline 41 and / or the production tree jumper 44, and the flowmeter 42 can be a multiphase flowmeter. Chemical reagent injection holes, temperature and pressure sensors, sand production monitors, and other devices can also be provided on the subsea pipeline 41 and / or the production tree jumper 44 for chemical reagent injection, temperature and pressure monitoring, and sand production monitoring, etc.

[0051] Preferably, one end of the later-installed production tree jumper 44 is detachably connected to the production tree 21, and the other end of the production tree jumper 44 is detachably connected to the subsea pipeline 41 to converge the oil and gas collected by the production tree 21 to the subsea pipeline 41 and then transport it to the outside through the subsea pipeline 41. Through the detachable connection method of the production tree jumper 44, the production tree 21 and the subsea pipeline 41 can be quickly and safely connected or disconnected to meet different production requirements and maintenance operations. The detachable connection method can be a flange connection, a claw connection, a clamp connection, a threaded connection, or other connection methods.

[0052] The flying lead assembly includes a plurality of flying leads. For example, the flying leads can include electrical flying leads, hydraulic flying leads, and optical flying leads. The electrical flying leads are mainly used to transmit electricity to ensure that the electricity can be stably and reliably transmitted to each underwater device, thus maintaining the normal operation of the concealed underwater production facility 100. The hydraulic flying leads are used to transmit hydraulic power, which is an important energy source for driving underwater devices such as valves and pumps to support the normal operation and efficient operation of the concealed underwater production facility 100. The optical flying leads are used to transmit communication signals to ensure unobstructed information between the underwater devices and the onshore control center. Preferably, both ends of the flying lead are detachably connected, so that the flying lead can be quickly and safely connected or disconnected to meet different production requirements and maintenance operations.

[0053] In some embodiments, please refer to Figure 10, along the vertical direction X, the top cover 11 and the base 12 are oppositely arranged, and the projected area of the base 12 is larger than that of the top cover 11, so that the base 12 has a larger supporting area and can more stably support the entire concealed underwater production facility 100, providing better stability and the ability to resist deformation. The concealed underwater production facility 100 includes a protective structure 5, and the protective structure 5 is an inclined protective wall. The two sides of the protective wall are respectively connected to the top cover 11 and the base 12. The angle between the surface of the protective structure 5 and the vertical direction X is an acute angle, so that when the concealed underwater production facility 100 is subjected to lateral forces, the protective structure 5 can more effectively disperse and resist these forces, thereby increasing the stability of the entire concealed underwater production facility 100. The protective structure 5 can be used to prevent the dragging of large debris in the sea such as fishing nets and ship anchors. In addition, the inclined protective structure 5 and the base 12 with a larger area can more effectively guide impurities such as sediment to flow down along the protective structure 5 and be discharged outside the mud surface box body 1, reducing the accumulation and penetration of impurities such as sediment on the surface of the mud surface box body 1, thereby improving the performance of preventing impurities such as sediment and reducing the cleaning difficulty and maintenance cost.

[0054] In some embodiments, the base 12 is a hollow structure, so that the liquid and sediment entering the interior of the mud surface box body 1 can be discharged from the base 12. Preferably, the base 12 can be composed of round tubes and / or steel sections to facilitate the processing and preparation of the base 12. For example, the base 12 includes a number of steel sections distributed crosswise to form a stable load-bearing frame. The steel sections are fixed and connected through connectors, and the connectors can be the cooperation of bolts and nuts. Of course, the steel sections can also be fixed by welding. And / or, the protective structure 5 is provided with mesh holes. Specifically, the aperture of the mesh holes is small, so that the liquid can pass through the mesh holes, but the sediment cannot pass through the mesh holes, thereby reducing the entry of external sediment into the space between the mud surface box body 1 and the protective structure 5 through the protective structure 5.

[0055] In some embodiments, the concealed underwater production facility 100 includes driven piles, at least a part of which is disposed at the bottom of the base 12 for fixing the concealed underwater production facility 100 to the underwater mud. The number of driven piles is preferably two, three or four. Of course, the number of driven piles can also be more than four. Alternatively, the concealed underwater production facility 100 includes suction piles, which are disposed at the bottom of the base 12. By driving the sinking and floating of the suction piles, the overall sinking and floating of the system can be driven, thereby realizing the installation and recovery of the concealed underwater production facility 100, enabling the concealed underwater production facility 100 to be reused, and thus reducing the development cost of marginal oilfields. The number of suction piles is preferably two, three or four. Of course, the number of suction piles can also be more than four. And / or, the concealed underwater production facility 100 includes a sinker plate 6, which is disposed at the bottom of the base 12. The sinker plate 6 can bear multi-dimensional loads to improve the bearing capacity and stability of the concealed underwater production facility 100. The concealed underwater production facility 100 of the present application can adopt either driven piles or suction piles.

[0056] The present invention also provides a method for using a concealed underwater production facility, including: integrally disposing at least a part of the underwater production assembly 2 on the integrated support structure 14 of the subsea box 1 to form an integrated skid-mounted underwater production assembly; assembling the top cover 11, the base 12, the side wall 13 and the integrated support structure 14 integrally provided with at least a part of the underwater production assembly 2 to obtain the concealed underwater production facility 100; setting a foundation pit 10 on the underwater mud surface; and lowering the concealed underwater production facility 100 into the foundation pit 10 on the underwater mud surface. Before the entire concealed underwater production facility 100 is lowered underwater, the drilling conduit and other equipment of the underwater production assembly 2 can be first integrally disposed on the integrated support structure 14 of the subsea box 1 for integration and then lowered underwater together with the subsea box 1. Compared with the method of first lowering the subsea box 1 under the mud surface and then using a hoisting device to lower the drilling conduit and other equipment of the underwater production assembly 2 into the subsea box 1 for installation, the installation cost of the concealed underwater production facility 100 can be reduced.

[0057] The working process of the concealed underwater production facility 100 of the present invention is described below:

[0058] First, manufacture the sub-mud surface box body 1, which includes a top cover 11, a base 12, side walls 13, and an integrated support structure 14. Before the concealed underwater production facility 100 is launched, pre-installation is required, that is, install equipment of the concealed underwater production facility 100 such as the umbilical cable terminal 33, the underwater routing module 32, the underwater control module 31, the subsea pipeline 41, the flowmeter 42, the underwater valve 43, the production tree jumper 44, the drilling conductor, and the flying lead (which can also be installed later) on the sub-mud surface box body 1 to form a preliminary overall structure of the concealed underwater production facility 100; then launch the preliminary overall structure of the pre-installed concealed underwater production facility 100 and place it in the underwater foundation pit 10; after the preliminary overall structure is placed in the foundation pit 10, drill the oilfield through the drilling conductor; after drilling is completed, open the second cover 113 at the equipment inlet and outlet, and then lift the production tree 21 into the sub-mud surface box body 1 by a hoisting device and install it on the wellhead installed later inside the drilling conductor; then open the first cover 112 at the diver inlet and outlet to allow the diver to enter the diver passage 14b inside the sub-mud surface box body 1, and the diver connects and fixes the production tree jumper 44 and the flying lead accordingly to form a complete overall structure of the concealed underwater production facility 100. Then connect the umbilical cable 34 outside the sub-mud surface box body 1; if necessary, connect the power cable. Connect the production tree jumper 44 to the subsea pipeline 41. In this way, the concealed underwater production facility 100 can carry out oil production work. When the concealed underwater production facility 100 finishes working and needs to be recovered, disconnect the production tree 21 from the wellhead, the production tree jumper 44, and the flying lead, and remove the production tree 21 from the sub-mud surface box body 1 by a hoisting device. Disconnect the connection between the sub-mud surface box body 1 and the subsea pipeline 41, the umbilical cable 34, and the power cable (if any). Then recover the concealed underwater production facility 100.

[0059] The embodiments of this specific implementation manner are all preferred embodiments of the present invention, and do not limit the protection scope of the present invention accordingly. Therefore, all equivalent changes made according to the structure, shape, and principle of the present invention shall be covered within the protection scope of the present invention.

Claims

1. A concealed underwater production facility suitable for use in restricted sea areas, characterized in that: The invention comprises a box body (1) below the mud surface, wherein the box body (1) below the mud surface comprises a top cover (11) and a base (12), a side wall (13) is arranged between the top cover (11) and the base (12), and the top cover (11), the base (12) and the side wall (13) together enclose a receiving chamber (1a); an underwater production component (2) is arranged in the receiving chamber (1a), and the underwater production component (2) comprises a drilling conduit and a Christmas tree (21), and the Christmas tree (21) is fixed to a wellhead inside the drilling conduit.

2. The concealed underwater production facility suitable for use in restricted sea areas according to claim 1 is characterized in that: An integrated support structure (14) is provided between the top cover (11) and the base (12) of the box body (1) below the mud surface; the integrated support structure (14) is connected with the base (12) and the side wall (13) to form a structural whole; and the underwater production assembly (2) and the integrated support structure (14) are integrated into a skid.

3. The concealed underwater production facility suitable for use in restricted sea areas according to claim 2 is characterized in that: The integrated support structure (14) has a first surface (141) facing the top cover (11), an opening (14a) is formed in the middle of the first surface (141), and a portion of the Christmas tree (21) passes through the opening (14a) in the vertical direction; the first surface (141), the side wall (13) and the top cover (11) together enclose a diver's passage (14b), and the diver's passage (14b) surrounds the opening (14a).

4. The concealed underwater production facility suitable for use in restricted sea areas according to claim 1 is characterized in that: The top cover (11) comprises a top cover body (111), a diver inlet and an equipment inlet are provided on the top cover body (111), a first cover member (112) is provided on the diver inlet and an equipment inlet is provided on the top cover, and a second cover member (113) is provided on the equipment inlet and an equipment inlet; along the vertical direction, a projection of the equipment inlet and an equipment inlet on the first surface (141) overlaps at least part of the opening (14a), and a projection of the diver inlet and an equipment inlet on the first surface (141) overlaps at least part of the diver channel (14b).

5. The concealed underwater production facility suitable for restricted sea areas according to claim 1 is characterized in that: The underwater production assembly (2) further comprises an underwater distribution unit (3), a pipeline assembly (4) and a flying line assembly; the underwater distribution unit (3) is connected to the pipeline assembly (4) and the Christmas tree (21) via the flying line assembly, and the pipeline assembly (4) is connected to the Christmas tree (21); the underwater distribution unit (3) is fixed to the upper surface of the integrated support structure (14), and at least part of the pipeline assembly (4) and the flying line assembly is fixed to the base (12) and / or a side of the integrated support structure (14) away from the underwater distribution unit (3).

6. The concealed underwater production facility suitable for use in restricted sea areas according to claim 5 is characterized in that: The underwater distribution unit (3) comprises an umbilical cable terminal (33), an underwater routing module (32) and an underwater control module (31); the umbilical cable terminal (33) is connected to the Christmas tree (21) via the underwater routing module (32) and the underwater control module (31).

7. The concealed underwater production facility suitable for use in restricted sea areas according to claim 5 is characterized in that: The pipeline assembly (4) comprises a sea pipe (41), a flow meter (42), a subsea valve (43) and a Christmas tree jumper pipe (44); the sea pipe (41) is connected to the Christmas tree (21) via the Christmas tree jumper pipe (44); the sea pipe (41) and / or the Christmas tree jumper pipe (44) are provided with a flow meter (42) and a subsea valve (43).

8. The concealed underwater production facility suitable for use in restricted sea areas according to claim 1 is characterized in that: The concealed underwater production facility further comprises a protective structure (5) located outside the box (1) below the mud surface, the protective structure (5) being an inclined protective wall, the two sides of which are respectively connected to the top cover (11) and the base (12), the projection area of ​​the base (12) being larger than the projection area of ​​the top cover (11); the angle between the surface of the protective structure (5) and the vertical direction is an acute angle; the base (12) is a hollow structure; and / or the protective structure (5) is provided with mesh holes.

9. The concealed underwater production facility suitable for use in restricted sea areas according to claim 1 is characterized in that: The concealed underwater production facility also includes at least one of a hammer pile, a suction pile and an anti-sinking plate arranged at the bottom of the base (12).

10. A method for using the concealed underwater production facility applicable to restricted sea areas according to any one of claims 1 to 9, characterized in that: include Integrate at least part of the underwater production component (2) into the integrated support structure (14) of the box (1) below the mud surface to form an integrated skid-mounted underwater production component; Assembling the top cover (11), the base (12), the side wall (13) and the integrated support structure (14) integrated with at least part of the underwater production component (2) to obtain a concealed underwater production facility; Setting up foundation pit on underwater mud surface; The concealed underwater production facility is lowered into a foundation pit on the underwater mud surface.

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