A rotatable rig and drillship structure

Abstract

The present application relates to a kind of rotatable drilling platform and drilling ship structure, belong to marine engineering technical field, it includes main hull, be set on the drilling platform support of main hull, be set on the winch of main hull and be located the outer periphery of drilling platform support, be set on the drilling platform of drilling platform support, and be set on the derrick of drilling platform, main hull is opened with moon pool opening, drilling platform support is set to multiple and is distributed in the outer periphery of moon pool opening, winch can drive drilling platform support around moon pool opening axis on main hull rotation and / or to the fixed binding of drilling platform support.The drilling platform in the present application can be slidably rotated on the hull deck, when the bow is adjusted at an angle with the direction of the sea waves, the drilling platform can rotate in the opposite direction, ensuring that various pipelines are not entangled, ensuring the positioning accuracy of the dynamic positioning system, so that the ship is not affected by the changes in the sea waves, thereby improving the efficiency of drilling operations.

Description

Technical Field

[0001] This invention relates to drilling vessels with drilling capabilities, and more particularly to drilling vessels with independent drilling rig structures, belonging to the field of marine engineering technology. Background Technology

[0002] Nowadays, deep-sea drilling is mainly achieved through drilling ships and drilling platforms. Drilling platforms can usually fix the center position of the wellhead by mooring at multiple points, but drilling ships are positioned by dynamic positioning (DP) equipment at the fore and aft of the hull.

[0003] During the operation of drilling ships at sea to drill deep wells, from the start of the ship's dynamic positioning to the drilling, drilling, fixing the wellhead, completing the drilling task, and then recovering the drill pipe, the time cycle often takes more than 5 days, and the time cycle gradually increases with the depth of the well.

[0004] During dynamic positioning, ship positioning systems (DP) often adjust the ship's bow orientation according to the direction of the waves (to ensure a favorable wave angle). Maintaining the bow facing the waves is crucial for successful and accurate positioning. However, if the wave direction is at a significant angle to the bow (e.g., above 15°), the area of ​​the hull exposed to the waves increases, leading to increased wave loads. When these loads reach a certain level, the DP system may gradually fail, affecting drilling accuracy and potentially forcing a halt to drilling operations.

[0005] Meanwhile, when the bow adjusts its angle too much with the waves, the pipelines (hydraulic lines, signal control lines, cables, coolant lines, etc.) connecting to the riser from the drilling rig will become entangled. Because the riser cannot be rotated after it is connected, when the drilling rig rotates with the ship, many pipelines will become entangled, which will restrict the bow's direction adjustment and cause the drilling plan to be terminated prematurely.

[0006] When drilling vessels are operating in deep water, large changes in wave angle can significantly impact their dynamic positioning capabilities, and in extreme cases, the drilling mission may be terminated prematurely.

[0007] Therefore, the existing technology has the following technical problems: during dynamic positioning, when the bow rotates at a large angle, the pipelines will become entangled, affecting the safety of system operation and reducing operation efficiency. Summary of the Invention

[0008] To address the aforementioned issues, a rotatable drilling rig design for use on drilling vessels is proposed. The rig can slide and rotate on the ship's deck. When the bow adjusts its angle according to the wave direction, the rig can rotate in the opposite direction, ensuring that various pipelines are not entangled, guaranteeing the positioning accuracy of the dynamic positioning system, and preventing the ship from being affected by wave changes, thereby improving drilling efficiency.

[0009] To achieve the above objectives, the present invention provides a rotatable drilling platform and drilling vessel structure, including a main hull, a drilling platform support mounted on the main hull, a winch mounted on the main hull and located on the outer periphery of the drilling platform support, a drilling platform mounted on the drilling platform support, and a derrick mounted on the drilling platform. The main hull has a moon pool opening, and multiple drilling platform supports are provided and evenly distributed on the outer periphery above the moon pool opening. The winch can drive the drilling platform support to rotate around the axis of the moon pool opening on the main hull and / or fix and bind the drilling platform support.

[0010] Preferably, the drill platform support and the winch support are connected by a wire rope buckle.

[0011] Preferably, the cross-section of the drill platform leg includes a fan-shaped ring structure, wherein the centers of the two arcs of the fan-shaped ring structure coincide with the center of the moon pool opening.

[0012] Preferably, a reinforcing rib connects the two arcs of the fan-ring structure.

[0013] Preferably, the drill rig legs are equipped with winch tension eye plates for connecting wire rope buckles.

[0014] Preferably, each of the drill rig legs has two winch tension eye plates, located at both ends of the long arc of the fan ring.

[0015] Preferably, the moon pool opening has a drill platform leg support structure extending outward, and the drill platform bracket is mounted on the drill platform leg support structure.

[0016] Preferably, the top of the drill rig leg support structure is provided with a wear-resistant deck, and the drill rig legs are disposed on the wear-resistant deck.

[0017] Preferably, the wear-resistant deck is provided with annular wear-resistant limiting baffles on both the outer and inner rings of the drilling platform legs.

[0018] Preferably, the side of the wear-resistant limiting baffle away from the drill rig leg is connected to the wear-resistant deck with a supporting elbow plate.

[0019] This application differs from existing related technologies, solving the problem of riser pipe entanglement and the problem that the bow of the drilling vessel cannot be rotated at will due to changes in sea waves during long-term drilling operations, which makes it impossible to guarantee the accuracy of DP. Attached Figure Description

[0020] Figure 1 This is a top view of the ship's hull.

[0021] Figure 2 A schematic diagram showing the bow of a drilling vessel rotating with the waves during operations. Figure 3 A schematic diagram showing the winch pulling the outriggers of the drilling rig. Figure 4 A schematic diagram showing the pull force of the winch when the bow is rotated 30°. Figure 5 A schematic diagram showing the pull force of the winch when the bow is rotated 60°. Figure 6 A schematic diagram showing the pulling force of the winch when the bow is rotated 90°. Figure 7 This is a schematic diagram of the cross-section of the drill rig's support leg; Figure 8 Schematic diagram of the sliding drilling rig legs on the deck; Figure 9 This is a top view of the drilling rig; Figure 10 Diagram illustrating the three positioning and tying methods for the outriggers of a drilling rig. Figure 1 ; Figure 11 Diagram illustrating the three positioning and tying methods for the outriggers of a drilling rig. Figure 2 ; Figure 12 Diagram illustrating the three positioning and tying methods for the outriggers of a drilling rig. Figure 3 .

[0022] Reference numerals: 1. Moon pool opening; 11. Structural support bulkhead; 2. Drill platform leg; 21. Drill platform leg support structure; 22. Winch; 23. Winch wire rope tension direction; 24. Winch tension eye plate; 25. Reinforcing rib; 26. Power supply station; 27. Battery emergency power supply station; 3. Drill platform surface; 31. Turntable opening; 4. Wear-resistant deck; 41. Support elbow plate; 42. Wear-resistant limit baffle. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] 1. Layout scheme of the rotatable drilling rig This application provides a rotatable drilling platform and hull design that, during drilling operations, can ensure that hydraulic lines do not become entangled when the bow angle is adjusted by rotating the drilling platform.

[0025] like Figure 1 As shown, the circular opening in the middle circle is the moon pool opening 1 in the middle of the drilling vessel's hull. The two dotted lines extending outward from the moon pool opening 1 are the drilling platform leg support structure 21, which is responsible for supporting the drilling platform legs 2 and also serves as the track support for the rotation and sliding of the drilling platform legs 2.

[0026] 2. The relationship between the ship's rotation with the waves and the center of the moon pool. During drilling operations, dynamic positioning must ensure that the center of the moon pool remains constant. When the bow adjusts its direction, the relative position between the moon pool center and the underwater wellhead center must also remain unchanged. Therefore, the bow rotation angle is as follows: Figure 2 As shown.

[0027] Dynamic positioning systems typically have a maximum and minimum range of wave angles they can withstand. For example, when the angle between the wave and the hull is ±15°, dynamic positioning (DP) can work normally. However, as the angle increases, the DP will fail as the wave force on the hull gradually increases, and the hull will be pushed away by the waves, causing the center of the moon pool to be out of its original position.

[0028] Assuming that at the beginning of drilling operations, the main hull is in a wave-facing state (i.e., waves directly hit the bow and flow towards the stern), as the weather changes, wind direction, and wave direction change, and gradually exceed the maximum angle range that the DP can withstand, the DP should adjust the bow angle to adapt to the wave changes. Figure 2 The text only states that the maximum angle at which the bow turns to the port side is 90°, but the actual application angle of this application is 360° full coverage.

[0029] 3. How to achieve drill table rotation To prevent pipeline entanglement, the drilling rig needs to maintain a constant relative position to the center of the moon pool, or have an acceptable angle of rotation. Therefore, if the bow rotates too much, drilling rig support leg 2 needs to be rotated in the opposite direction for adjustment. The rotation scheme for drilling rig support leg 2 is described in [link to diagram]. Figure 3 As shown.

[0030] Depend on Figure 3 As shown, the drilling platform legs 2 are driven by four winches 22 on the ship's deck, which pull the legs 2 to slide. When the ship rotates counterclockwise as shown, the pulling force of the winches 22 should be clockwise, as indicated by the arrows in the figure. For ease of observation, the four drilling platform legs 2 are numbered as 1, 2, 3, and 4 in the figure. Under the pulling force of the winches 22, the entire drilling platform leg 2 slides within a specific circular track (limiting groove), thus realizing the rotational function of the drilling platform and its legs 2. When the ship rotates too much, the wire rope of the winches 22 needs to be unhooked and rewound to another drilling platform leg 2 before being pulled again to achieve the large-angle rotation function. Figures 4 to 6 The diagram shows the bow being pulled at a large angle.

[0031] Figure 6 The diagram illustrates the pulling force of winch 22 when the bow rotates 90°. This diagram demonstrates how, by repeatedly disassembling and reassembling the wire rope buckles of winch 22, the rotatable function of the drilling platform's outrigger 2 can be achieved through pulling. (Comparison) Figure 3 and Figure 6 The positions of the drilling platform's outriggers 1, 2, 3, and 4 remained unchanged, while the hull had rotated 90°.

[0032] 4. How are the drilling platform outriggers 2 connected to the ship's deck? First, the cross-sectional structure of the drilling platform support leg 2 needs to be a closed, hollow fan-shaped box, with the bottom connected to the main hull deck and the top welded to the drilling platform.

[0033] When the drill rig support leg 2 is slidable at the ship's deck due to being pulled by winch 22, then the drill rig support leg 2 must not be welded to the main hull. To ensure that the drill rig support leg 2 always has structural support inside the main hull, its sliding trajectory must also be circular. Therefore, the two sides of the fan-shaped drill rig support leg 2 must be formed by arcs, equal to the radius of the circular support inside the ship's interior. The cross-section of the drill rig support leg 2 is shown below. Figure 5 As shown.

[0034] Figure 7 The cross-section of drill platform leg 2 is shown in the figure. As can be seen, two sides of drill platform leg 2 are formed by arcs, allowing it to slide along the supporting arc of the ship's deck. It maintains a supporting structure at any position, ensuring the structural strength meets requirements. The winch tension eye plate 24 in the figure provides the attachment and detachment buckle for the winch 22's wire rope. The winch 22 can slide the drill platform leg 2 by pulling on the eye plate. The reinforcing rib 25 in the drawing is necessary to ensure the strength of drill platform leg 2.

[0035] Figure 8 A schematic diagram of the sliding drilling rig support leg 2 at the deck is shown, as follows: Figure 8 As shown, the drill rig legs 2 slide between the wear-resistant limiting baffles 42 on the hull deck.

[0036] 5. How to solve the power supply problem? When the outrigger 2 slides on the hull of the drilling rig, problems arise with the power supply cables for the equipment on the rig. Since the cables are non-retractable, this restricts the rotation angle between the drilling rig and the hull. The solution is to install a power supply station 26 on the deck, as detailed in [link to details]. Figure 1 .

[0037] Figure 1 This shows a top view of one moon pool opening on the hull, from... Figure 1As can be seen, power is supplied by setting up power supply stations 26 on the deck, with a total of 4 power supply stations 26. The cables that supply power to the equipment on the drilling rig usually connect upwards from the internal space of the legs to the top of the drilling rig. When the drilling rig legs 2 rotate to any angle, they will be relatively close to the adjacent power supply stations 26. By setting up jumper connectors on the cables, the connection to any power station can be adjusted at any time, thus solving the power supply problem.

[0038] In addition, a battery emergency power station 27 is installed at the top of the drilling rig, which can temporarily ensure system safety when the power station 26 below experiences a power failure. See details. Figure 7 .

[0039] Figure 9 A top view of the drilling rig is shown, from Figure 9 As can be seen, the emergency battery power station 27 on the top of the drilling rig can solve the problem of temporary power outages.

[0040] 6. How to secure the second outrigger of the drilling rig after it has slid into place? After the drilling platform outrigger 2 slides to the designated position, the position of the wire rope is adjusted, and it is tightened and secured by winch 22. Figure 10 As shown, when any of the drill platform legs 2 are in any position in the figure, they can be fixed by locking them with the pulling force of the winch 22.

[0041] Figures 10 to 12 The diagram shows three different positioning and securing methods for the rig's outrigger 2. 7. Other issues explained In the existing technical solution, the support structure 22 that is reinforced and radiates outwards inside the hull corresponding to the drilling leg 2 is divided into 12 parts within the 360° arc range where the drilling leg 2 can slide, that is, each part is 30°; the size of each drilling leg 2 is also equal to any one of the parts divided into, so as to ensure that the four bulkheads of the drilling leg 2 are exactly aligned with the support structure under the hull deck and meet the strength requirements.

[0042] In this scheme, the angle at which the winch 22 pulls the drilling platform support leg 2 each time must also be 30°. However, the patent application intends to express that each slide is not limited to every 30° increment. This is just for illustration. It can be changed to every 10°, 15°, 30° or 45° increment as needed, as long as the internal reinforcement structure of the hull can meet the construction space requirements.

[0043] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A rotatable drilling rig and drilling vessel structure, characterized in that, The system includes a main hull, drilling platform legs (2) mounted on the main hull, a winch (22) mounted on the main hull and located on the outer periphery of the drilling platform legs (2), a drilling platform mounted on the drilling platform legs (2), and a derrick mounted on the drilling platform. The main hull has a moon pool opening (1). The drilling platform legs (2) are multiple and evenly distributed on the outer periphery above the moon pool opening (1). The cross-section of the drilling platform legs (2) includes a fan-shaped ring structure. The centers of the two arcs of the fan-shaped ring structure are connected to the moon pool opening (1). 1) The center coincides, the drill leg (2) is connected to the winch (22) bracket with a wire rope buckle, the drill leg (2) is provided with a winch tension eye plate (24) for connecting the wire rope buckle, and each drill leg (2) has two winch tension eye plates (24) and is located at both ends of the long arc of the fan ring; the winch (22) can drive the drill leg (2) to rotate around the axis of the moon pool opening (1) on the main hull and / or fix and bind the drill leg (2).

2. The rotatable drilling platform and drilling vessel structure according to claim 1, characterized in that, A reinforcing rib (25) connects the two arcs of the fan-ring structure.

3. The rotatable drilling platform and drilling vessel structure according to claim 1, characterized in that, The moon pool opening (1) has a drill platform leg support structure (21) extending outward, and the drill platform leg (2) is located on the drill platform leg support structure (21).

4. The rotatable drilling platform and drilling vessel structure according to claim 3, characterized in that, The top of the drill rig leg support structure (21) is provided with a wear-resistant deck (4), and the drill rig leg (2) is located on the wear-resistant deck (4).

5. The rotatable drilling platform and drilling vessel structure according to claim 4, characterized in that, The wear-resistant deck (4) is provided with annular wear-resistant limiting baffles (42) on both the outer and inner rings of the drilling platform leg (2).

6. The rotatable drilling platform and drilling vessel structure according to claim 5, characterized in that, The wear-resistant limiting baffle (42) is connected to the wear-resistant deck (4) by a supporting elbow plate (41) on the side away from the drill leg (2).

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