Plugging device for moon pool in multi-wellhead floating platform and floating platform

Abstract

The plugging device for the moon pool in the multi-wellhead floating platform comprises a plugging body, and the plugging body is fixed to the bottom in the moon pool and seals an opening in the bottom of the moon pool. A plurality of first through holes used for ventilation and water permeation and a plurality of second through holes allowing vertical pipes to penetrate through are formed in the plugging body in the vertical direction, the plugging device separates water inside the moon pool from water outside the moon pool, the plugging device moves synchronously with the floating body, and therefore the water inside the moon pool is restrained; free movement of water in the moon pool is effectively reduced, and adverse effects of water resonance in the moon pool on floating body movement are reduced; in addition, the plugging body is fixed to the bottom in the moon pool, the vertical pipe penetrates through the second through hole in the plugging body, effective transverse support can be provided for the vertical pipe, and interference and collision of the vertical pipe under the large-plane deviation condition of the floating platform are avoided.

Description

Technical Field

[0001] The invention relates to the technical field of deepwater oil and gas field development, and in particular to a plugging device for a moon pool in a multi-wellhead floating platform and a floating platform. Background Art

[0002] The moon pool is usually a riser channel of an offshore floating platform. The channel passes vertically from top to bottom through the floating part of the floating platform, and the inner side of the channel is connected to the seawater. The drilling riser or dry production riser passes through the moon pool to connect the floating platform with the seabed wellhead, thereby realizing the development of oil and gas fields. With the acceleration of deepwater oil and gas development and the expansion of development scale, the increase in the number of dry wellheads has caused the moon pool to expand significantly. The scale of the water body in the moon pool has increased accordingly, and the nonlinear hydrodynamic characteristics brought about by it have become more obvious, resulting in a significant rise in liquid level, endangering the safety of the equipment on the top of the riser, and generating additional pitch moment, aggravating the dynamic tilt angle of the platform. Due to the large number of risers arranged in the moon pool, interference and collision are prone to occur under the resonance condition of the moon pool water body, threatening the service safety of the dry riser.

[0003] Therefore, there is an urgent need for a new plugging device for the moon pool in a multi-wellhead floating platform and a floating platform to solve the above technical problems. Summary of the invention

[0004] The present invention aims to solve the above technical problems, that is, to solve the existing problems that with the acceleration of deepwater oil and gas development and the expansion of development scale, the increase in the number of dry wellheads causes the size of the moon pool to expand significantly, and the scale of the water body in the moon pool increases accordingly, which brings more and more obvious nonlinear hydrodynamic characteristics, resulting in a significant liquid level rise, endangering the safety of the equipment on the top of the riser, and at the same time generating additional pitch moment, aggravating the dynamic tilt angle of the platform, and because a large number of risers are arranged in the moon pool, interference and collision are prone to occur under the resonance condition of the moon pool water body, threatening the service safety of the dry riser.

[0005] To this end, in a first aspect, the present invention provides a plugging device for a moon pool in a multi-wellhead floating platform, comprising a plugging body, wherein the plugging body is fixed to the bottom of the moon pool and seals the bottom opening of the moon pool, and the plugging body is provided with a plurality of first through holes for air and water permeability and a plurality of second through holes for rising pipes to pass through in a vertical direction.

[0006] In the specific embodiment of the above-mentioned sealing device for the moon pool in a multi-wellhead floating platform, the sealing body includes an upper sealing plate and a lower sealing plate distributed up and down, the upper sealing plate and the lower sealing plate are fixedly connected by a plurality of spaced support rods, and the first through hole and the second through hole penetrate the upper sealing plate and the lower sealing plate.

[0007] In the above-mentioned specific implementation of the plugging device for the moon pool in a multi-wellhead floating platform, an elastic member is provided between the inner wall of the second through hole and the outer wall of the riser to separate the two.

[0008] In the above specific implementation of the plugging device for the moon pool in a multi-wellhead floating platform, the diameter of the second through hole is 1.5 times the diameter of the riser.

[0009] In the above-mentioned specific implementation of the plugging device for the moon pool in a multi-wellhead floating platform, guides in the shape of a flared mouth are respectively installed at the top and bottom ends of the second through hole.

[0010] In the above-mentioned specific implementation of the plugging device for the moon pool in a multi-wellhead floating platform, the inclination angle of the horn opening of the guide is 45°-60°.

[0011] In the above-mentioned specific implementation of the plugging device for the moon pool in a multi-wellhead floating platform, the top wall surface and the bottom wall surface in the elastic sleeve are both conical surfaces.

[0012] In the specific implementation of the above-mentioned plugging device for the moon pool in a multi-wellhead floating platform, the plugging body is fixedly connected to the bulkhead of the moon pool area and the strong crossbeam in the floating platform.

[0013] In the specific implementation of the above-mentioned plugging device for the moon pool in a multi-wellhead floating platform, the plugging body is provided with multiple rows of first hole groups distributed at intervals, each row of the first hole group includes a plurality of first through holes arranged at equal intervals, and the first through holes in two adjacent rows of the first hole groups are staggered.

[0014] In a second aspect, the present invention further provides a floating platform, comprising a buoy, wherein a moon pool is provided on the buoy, wherein a plugging device for a moon pool in a multi-wellhead floating platform as described in any one of the first aspects is installed in the moon pool.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. The blocking device designed in the present invention separates the water inside the moon pool from the external water, and its movement is synchronized with the floating body, thereby realizing the constraint of the water inside the moon pool, effectively reducing the free movement of the water inside the moon pool, and reducing the adverse effect of the resonance of the water body in the moon pool on the movement of the floating body.

[0016] 2. The plugging body designed in the present invention is fixed at the bottom of the moon pool, and the riser passes through the second through hole on the plugging body, which can provide effective lateral support for the riser and avoid interference and collision of the riser under the condition of large plane offset of the floating platform.

[0017] 3. The plugging device designed in the present invention is connected with the bulkhead and strong cross beam of the floating body, so as to ensure the continuity of the overall structure and thus improve the overall strength. The overall structure is simple and can be installed during the construction of the hull, thus reducing the difficulty of construction and installation.

[0018] 4. An elastic member is provided between the inner wall of the second through hole and the outer wall of the riser to separate the two. The elastic member is elastic and can reduce the collision load between the riser and the blocking body when the floating body moves, thereby ensuring the safety of the riser. The guide is provided in a trumpet shape to facilitate the passage of the riser.

[0019] 5. The plugging body designed in the present invention is filled with water in the in-place state, which reduces the pressure difference between the inside and outside of the in-place state and effectively saves construction steel. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings, in which: Figure 1 It is a structural schematic diagram of a plugging device for a moon pool in a multi-wellhead floating platform provided by the present invention installed in the moon pool; Figure 2 It is a schematic diagram of the structure of the elastic member and the guide installed on the plugging body; Figure 3 is a top view of the plugging device; Figure 4 It is a structural schematic diagram of the plugging body; Figure 5 It is a comparison chart of the platform heave and sink movement before and after the installation of the plugging device verified by the water tank test.

[0021] List of reference numerals: 1. Floating body; 2. Moon pool; 3. Sealing device; 31. Guide; 32. Elastic member; 33. First through hole; 34. Sealing body; 341. Upper sealing plate; 342. Lower sealing plate; 343. Support rod; 35. Second through hole; 4. Standpipe. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0023] In the description of the present invention, it should be noted that the directions or positional relationships indicated by the terms "upper", "lower", "inner", "outer", etc. are based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the system or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", etc. are used to define components, only for the convenience of distinguishing the above components, and unless otherwise stated, the above terms have no special meanings and cannot be understood as indicating or implying relative importance.

[0024] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "setting", and "connection" 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 an indirect connection 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 the present invention can be understood according to specific circumstances.

[0025] The present invention relates to the technical field of deepwater oil and gas field development, and in particular to a plugging device for a moon pool in a multi-wellhead floating platform and a floating platform. The purpose is to solve the problem that as the development process of deepwater oil and gas is accelerated and the scale of development is expanded, the number of dry wellheads increases, resulting in a significant expansion of the scale of the moon pool. The scale of the water body in the moon pool increases accordingly, and the nonlinear hydrodynamic characteristics brought about by it become more and more obvious, resulting in a significant rise in liquid level, endangering the safety of the equipment on the top of the riser, and at the same time generating additional pitch moment, aggravating the dynamic tilt angle of the platform. Since a large number of risers are arranged in the moon pool, interference collisions are prone to occur under the resonance condition of the moon pool water body, thereby threatening the service safety of the dry risers. To this end, the present invention provides a plugging device for a moon pool in a multi-wellhead floating platform, comprising a plugging body, the plugging body is fixed to the bottom of the moon pool and seals the bottom opening of the moon pool, and a plurality of first through holes for air and water permeability and a plurality of second through holes for the risers to pass through are provided on the plugging body along the vertical direction. In this application, the vertical direction refers to Figure 1 In the up-down direction, that is, the axial direction of the riser, the plugging device designed in the present application separates the water body inside the moon pool from the external water body, and its movement is synchronized with the floating body, thereby realizing the constraint on the water body inside the moon pool, effectively reducing the free movement of the water body inside the moon pool, and reducing the adverse effect of the resonance of the water body in the moon pool on the movement of the floating body; in addition, the plugging body designed in the present application is fixed at the bottom of the moon pool, and the riser passes through the second through hole on the plugging body, which can provide effective lateral support for the riser, and avoid interference and collision of the riser under the condition of large plane offset of the floating platform.

[0026] Hereinafter, a plugging device for a moon pool in a multi-wellhead floating platform provided by an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

[0027] See also Figure 1-4 The present invention provides a plugging device for a moon pool in a multi-wellhead floating platform, wherein the plugging device 3 comprises a plugging body 34, which is fixed to the bottom of the moon pool 2 and seals the bottom opening of the moon pool 2. The plugging body 34 is provided with a plurality of first through holes 33 for air and water permeability and a plurality of second through holes 35 for the riser to pass through in the vertical direction. In this application, the vertical direction refers to Figure 1 The up and down direction in the moon pool 2 is the axial direction of the riser. Specifically, the blocking body 34 is fixedly connected to the bulkhead of the moon pool area and the strong crossbeam in the floating platform. The provision of the first through hole 33 facilitates the entry of seawater into the moon pool 2. The blocking device 3 designed in the present application separates the internal water body of the moon pool 2 from the external water body, and its movement is synchronized with the floating body 1, thereby realizing the constraint on the internal water body of the moon pool 2, effectively reducing the free movement of the internal water body of the moon pool 2, and reducing the adverse effects of the resonance of the water body in the moon pool 2 on the movement of the floating body 1; in addition, the blocking body 34 designed in the present application is fixed to the bottom of the moon pool 2, and the riser passes through the second through hole on the blocking body 34, which can provide effective lateral support for the riser, and avoid interference and collision of the risers under the condition of large plane offset of the floating platform.

[0028] In one embodiment, see Figure 4 The sealing body 34 includes an upper sealing plate 341 and a lower sealing plate 342 which are distributed up and down. The upper sealing plate 341 and the lower sealing plate 342 are fixedly connected by a plurality of support rods 343 which are distributed at intervals. The first through hole 33 and the second through hole penetrate the upper sealing plate 341 and the lower sealing plate 342.

[0029] In addition, in the present application, the sealing body 34 can be made of steel material, which is easy to weld to the float 1 itself. Its shape and size can be adjusted according to the shape of the moon pool 2. It can be circular, rectangular, polygonal, etc., suitable for any moon pool 2 design, and can also adapt to different numbers of risers.

[0030] In one embodiment, see Figure 3 The blocking body 34 is provided with a plurality of rows of first hole groups distributed at intervals, each row of the first hole groups includes a plurality of first through holes 33 arranged at equal intervals, and the first through holes 33 in two adjacent rows of the first hole groups are staggered.

[0031] In the present application, the number and arrangement of the second through holes are not specifically limited, but are flexibly set according to the wellhead layout and the distribution and number of the risers, such as Figure 3 As shown, it can be seen from the distribution of the guides that the plurality of second through holes are arranged in a plurality of rows on the blocking body 34, and the spacing between adjacent second through holes in each row is equal.

[0032] In one embodiment, the diameter of the second through hole is 1.5 times the diameter of the standpipe.

[0033] It should be noted that the above-described second through hole diameter being 1.5 times the riser diameter is a typical example, and the specific size can be flexibly set according to the riser diameter and number.

[0034] In one embodiment, see Figure 2 An elastic member is provided between the inner wall of the second through hole and the outer wall of the vertical pipe to separate the two.

[0035] Specifically, the elastic member is an elastic sleeve, which is fixedly connected to the inner wall of the second through hole. Since the second through hole is provided on the upper sealing plate and the lower sealing plate, the top outer wall of the elastic sleeve is fixedly connected to the upper sealing plate, and the bottom outer wall of the elastic sleeve is fixedly connected to the lower sealing plate. The inner cavity of the elastic sleeve is used for the vertical pipe to pass through, and the inner wall of the elastic sleeve contacts the outer wall of the vertical pipe when the vertical pipe passes through. The elastic member is made of elastic rubber material.

[0036] In the above embodiment, the elastic member separates the inner wall of the second through hole from the outer wall of the riser. The elastic member is elastic and can reduce the collision load between the riser and the blocking body when the floating body moves, thereby ensuring the safety of the riser.

[0037] In one embodiment, see Figure 2 The top and bottom ends of the second through hole are respectively provided with guides in the shape of bell mouths, which play a guiding role and make it easier for the riser to pass through the second through hole. For example, the bell mouth of the guide has an inclination angle of 45°-60°.

[0038] In one embodiment, the top wall surface and the bottom wall surface in the elastic sleeve are both conical surfaces, which are convenient for connection with the guide.

[0039] In addition, see Figure 1 The present invention further provides a floating platform, including a floating body, a moon pool is provided on the floating body, and a plugging device for the moon pool in a multi-wellhead floating platform as described in any of the above various embodiments is installed in the moon pool.

[0040] See also Figure 5 The present application verifies through a water tank model test that the influence of waves on the rising and sinking movement of the floating platform after the plugging device is installed is significantly smaller than the influence of waves on the production movement of the floating platform when the plugging device is not installed. It can be seen that the present application separates the internal water body of the moon pool from the external water body through a plugging device, and its movement is synchronized with the floating body, thereby realizing the constraint of the internal water body of the moon pool, effectively reducing the free movement of the internal water body of the moon pool, and reducing the adverse effects of the resonance of the water body in the moon pool on the movement of the floating body.

[0041] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the protection scope of the technical solutions of the embodiments of the present invention.

Claims

1. A plugging device for a moon pool in a multi-wellhead floating platform, characterized in that: The plugging body comprises a plugging body which is fixed at the bottom of the moon pool and seals the bottom opening of the moon pool. The plugging body is provided with a plurality of first through holes for air and water permeability and a plurality of second through holes for vertical pipes to pass through in a vertical direction.

2. The plugging device for the moon pool in a multi-wellhead floating platform according to claim 1, characterized in that: The blocking body includes an upper sealing plate and a lower sealing plate which are distributed up and down. The upper sealing plate and the lower sealing plate are fixedly connected by a plurality of support rods which are distributed at intervals. The first through hole and the second through hole penetrate the upper sealing plate and the lower sealing plate.

3. The plugging device for a moon pool in a multi-wellhead floating platform according to claim 1, characterized in that: An elastic member is arranged between the inner wall of the second through hole and the outer wall of the standpipe to separate the two.

4. The plugging device for a moon pool in a multi-wellhead floating platform according to claim 3, characterized in that: The diameter of the second through hole is 1.5 times the diameter of the standpipe.

5. The plugging device for a moon pool in a multi-wellhead floating platform according to claim 1, characterized in that: The top end and the bottom end of the second through hole are respectively provided with guides in a bell-mouth shape.

6. The plugging device for a moon pool in a multi-wellhead floating platform according to claim 5, characterized in that: The horn opening of the guide has an inclination angle of 45°-60°.

7. The plugging device for a moon pool in a multi-wellhead floating platform according to claim 4, characterized in that: The top wall surface and the bottom wall surface in the elastic sleeve are both conical surfaces.

8. The plugging device for a moon pool in a multi-wellhead floating platform according to claim 1, characterized in that: The blocking body is fixedly connected to the bulkhead of the moon pool area and the strong cross beam of the floating platform.

9. The plugging device for a moon pool in a multi-wellhead floating platform according to claim 1, characterized in that: The blocking body is provided with a plurality of rows of first hole groups distributed at intervals, each row of the first hole groups includes a plurality of first through holes arranged at equal intervals, and the first through holes in two adjacent rows of the first hole groups are staggered.

10. A floating platform, characterized in that: The invention comprises a floating body, on which a moon pool is provided, in which a plugging device for a moon pool in a multi-wellhead floating platform as claimed in any one of claims 1 to 9 is installed.

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