Integrated underwater low pressure wellhead installation tieback tool

Abstract

This invention discloses an integrated subsea low-pressure wellhead installation and reconnection tool, comprising a main body and a reconnection connector. The main body includes a casing coupling, a body body, and an insertion connector connected in sequence. A rotating ring is fitted around the outside of the body, and multiple detachable guide arms are evenly distributed around the circumference of the rotating ring. The insertion connector connects to the low-pressure wellhead or the reconnection connector. The insertion connector is a sleeve structure, and its outer wall forms a locking structure, a guide groove, and a sealing structure from top to bottom. The reconnection connector includes an integrally formed large-diameter section and a small-diameter section. The inner wall of the large-diameter section forms a guide ramp, a limiting structure, and a connecting structure from top to bottom. This invention provides the functionality of two tools in one unit, reducing the number of tools and simplifying transportation, tool preparation, and maintenance. Reconnecting the tool to the low-pressure wellhead only requires pressing down and lifting, without rotation, thus reducing the requirements for the low-pressure wellhead tilt angle and platform positioning accuracy, and lowering the operational difficulty.

Description

Technical Field

[0001] This invention belongs to the field of oil and gas drilling and production equipment technology, specifically relating to an integrated underwater low-pressure wellhead installation and reconnection tool. Background Technology

[0002] The low-pressure wellhead is equivalent to the wellhead support ring of a surface wellhead. It is anchored to the seabed to form a solid foundation, supporting part of the weight of the wellbore, riser, and blowout preventer assembly. A 36-inch or 30-inch casing can be welded to the lower part of the low-pressure wellhead. The upper part of the low-pressure wellhead is equipped with a locking ring groove and an anti-rotation groove for easy connection to low-pressure wellhead service tools.

[0003] The friction between the low-pressure wellhead and the outer wall of the casing and the seabed soil forms a solid foundation on the seabed, supporting part of the weight of the wellbore, riser, and blowout preventer assembly.

[0004] Currently, conventional low-pressure wellheads require specialized installation tools and do not have the function of being reconnected to the work platform. A guide base plate is installed on the outside of the low-pressure wellhead, which can be used to install guide piles and guide ropes, serving as a device for guiding drilling tools, blowout preventers, and wellheads.

[0005] For reconnectable low-pressure wellheads, two types of service tools are available: a low-pressure wellhead installation tool and a low-pressure wellhead reconnection tool. The installation tool is used for initial installation, and the reconnection tool is used when reconnecting the wellhead to the platform after installation. However, there is a lack of tools on the market that combine installation and reconnection functions, allowing a single tool to perform both insertion and reconnection. Summary of the Invention

[0006] This invention is proposed to solve the problems existing in the prior art, and its purpose is to provide an integrated underwater low-pressure wellhead installation and reconnection tool.

[0007] This invention is achieved through the following technical solution:

[0008] An integrated subsea low-pressure wellhead installation and reconnection tool includes a main body and a reconnection connector. The main body comprises a casing coupling, a body body, and an insertion connector connected in sequence. A rotating ring is fitted around the outside of the body, and multiple detachable guide arms are evenly distributed around the circumference of the rotating ring. The insertion connector connects to the low-pressure wellhead or the reconnection connector. The insertion connector is a sleeve structure, and its outer wall forms a locking structure, a guide double-cone surface, and a sealing structure from top to bottom. The reconnection connector includes an integrally formed large-diameter section and a small-diameter section. The inner wall of the large-diameter section forms a guide inclined surface, a tool limiting structure, and a connecting structure from top to bottom.

[0009] In the above technical solution, the sleeve coupling is a sleeve structure with a sleeve female thread formed on its inner wall. The sleeve coupling is connected to the sleeve male thread through the sleeve female thread on its inner wall.

[0010] In the above technical solution, the body is a sleeve structure, with an upper limit ring and a lower limit ring sleeved on its outer wall, and a rotating ring placed between the upper limit ring and the lower limit ring.

[0011] In the above technical solution, multiple detachable guide arm connecting panels are evenly distributed along the circumference of the outer wall of the rotating ring. The number of detachable guide arm connecting panels is the same as the number of detachable guide arms. The detachable guide arms are connected to the detachable guide arm connecting panels by bolts.

[0012] In the above technical solution, the detachable guide arm includes a connecting plate, a connecting arm, and a guide horn connected in sequence; the connecting plate and the detachable guide arm connecting panel are connected by bolts.

[0013] In the above technical solution, the locking structure includes multiple sets of locking units evenly distributed along the circumference. Each locking unit is composed of multiple spaced upper locking bars. The gap between adjacent upper locking bars forms an upper locking groove. The upper locking bar is a horizontally placed rectangular bar structure, and the top surface of the upper locking bar is an inclined surface that slopes downward towards the center of the circle. A limiting block is provided above the locking unit.

[0014] In the above technical solution, the guide double cone surface is a V-shaped groove structure composed of an upper cone surface with a gradually decreasing diameter and a lower cone surface with a gradually increasing diameter; the sealing structure includes at least one sealing groove, and a sealing ring is provided in the sealing groove.

[0015] In the above technical solution, the outer wall of the feeding joint forms a lower anti-rotation block mounting groove, and the lower end of the body forms an upper anti-rotation block mounting groove; the lower anti-rotation block mounting groove is connected to the upper anti-rotation block mounting groove at the lower end of the body; the anti-rotation block is placed in the upper and lower anti-rotation block mounting grooves.

[0016] In the above technical solution, the guide slope is formed on the top surface of the large diameter section, and the guide slope is a slope that slopes downward from the circumference to the center; the connecting structure is the same as the locking structure of the feed connector; the tool limiting structure is composed of multiple tool limiting grooves evenly distributed along the circumference, and the tool limiting groove is a rectangular groove with a protrusion formed on one side of the groove wall.

[0017] In the above technical solution, multiple elastic shear pin mounting holes are evenly distributed along the circumference of the lower outer wall of the small diameter section, and elastic shear pins are installed in the elastic shear pin mounting holes; a sealing structure is provided on the bottom outer wall of the small diameter section, and the sealing structure includes at least one ring of return joint sealing groove.

[0018] The beneficial effects of this invention are:

[0019] This invention provides an integrated underwater low-pressure wellhead installation and reconnection tool. It connects to the low-pressure wellhead through a locking structure to realize the function of a low-pressure wellhead installation tool. It reconnects to the low-pressure wellhead through a reconnection joint and an elastic shear pin to realize the function of a low-pressure wellhead reconnection tool. The reconnection and separation process only requires pressing down and lifting, without rotation. It has lower requirements for the tilt angle of the low-pressure wellhead and the positioning accuracy of the platform, thus reducing the difficulty of operation. Attached Figure Description

[0020] Figure 1 This is a perspective view of the main body of the present invention;

[0021] Figure 2 This is the front view of the main body of the present invention;

[0022] Figure 3 This is a top view of the main body of the present invention;

[0023] Figure 4 yes Figure 3 Cross-sectional view along the AA direction;

[0024] Figure 5 This is a perspective view of the reconnector in this invention;

[0025] Figure 6 This is a front view of the reconnector in this invention;

[0026] Figure 7 This is a cross-sectional view of the reconnection connector in this invention;

[0027] Figure 8 This is a schematic diagram of the integrated underwater low-pressure wellhead used in this invention.

[0028] Figure 9 This is a cross-sectional view of the integrated underwater low-pressure wellhead used in this invention;

[0029] Figure 10 This is a diagram showing the usage status of the integrated underwater low-pressure wellhead installation for which the present invention is applied;

[0030] Figure 11 This is a diagram showing the usage status of the integrated underwater low-pressure wellhead reconnection of the present invention.

[0031] in:

[0032] 1. Main body;

[0033] 11. Sleeve coupling;

[0034] 12. Main body; 121. Upper limit ring; 122. Lower limit ring;

[0035] 13. Feed connector; 131. Limiting block; 132. Upper locking strip; 133. Guide double cone surface; 134. Sealing groove;

[0036] 14. Rotating ring; 141. Detachable guide arm connecting panel;

[0037] 15. Detachable guide arm; 151. Connecting plate; 152. Connecting arm; 153. Guide bell mouth;

[0038] 16. Anti-rotation block;

[0039] 2. Reconnect the connector;

[0040] 21. Large diameter section; 211. Guide slope; 212. Tool limiting groove; 213. Connecting structure;

[0041] 22. Small diameter section; 221. Flexible shear pin mounting hole; 222. Reconnection joint sealing groove;

[0042] 3. Flexible shear pin;

[0043] 4. Guide base plate;

[0044] 5. Guide piles;

[0045] A1. Low-pressure wellhead connection; A11. Tool guide ramp; A12. Limiting groove; A13. Feeding connector connection structure; A131. Connecting key; A132. Feeding connector connecting groove; A2. Low-pressure wellhead functional section; A21. Low-pressure wellhead return section; A211. Guide key; A212. Guide base plate heading adjustment groove; A213. Return connector limiting groove; A22. Installation limiting section; A221. Bolt hole; A222. Guide base plate limiting groove; A223. Service tool sealing groove; A224. High-pressure wellhead bearing ring; A23. Connection transition section; A3. Low-pressure wellhead casing connection; A4. Lifting bolt; A5. Disassembly bolt.

[0046] For those skilled in the art, other related figures can be obtained from the above figures without any creative effort. Detailed Implementation

[0047] To enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0048] Example 1

[0049] like Figures 1-7 As shown, an integrated underwater low-pressure wellhead installation and reconnection tool includes a main body 1 and a reconnection connector 2;

[0050] The main body 1 includes a sleeve coupling 11, a body 12 and a feed connector 13 welded from top to bottom. A rotating ring 14 is sleeved on the outside of the body 12. Multiple detachable guide arms 15 are evenly distributed around the outside of the rotating ring 14.

[0051] The casing coupling 11 is a sleeve structure with a casing female thread formed on its inner wall. The casing coupling 11 can be connected and sealed with the male thread of a large-size casing through the casing female thread on its inner wall, thus constructing the circulation channel required in drilling operations and bearing the tensile and bending loads during drilling.

[0052] The body 12 is a sleeve structure, with an upper limit ring 121 and a lower limit ring 122 welded to its outer wall, and a rotating ring 14 placed between the upper limit ring 121 and the lower limit ring 122; the upper limit ring 121 and the lower limit ring 122 provide vertical limitation for the rotating ring 14;

[0053] The lower end of the main body 12 forms an upper anti-rotation block mounting groove;

[0054] The inner diameter of the rotating ring 14 is larger than the outer diameter of the body 12; multiple detachable guide arm connecting panels 141 are evenly distributed along the circumference of the outer wall of the rotating ring 14, and the number of detachable guide arm connecting panels 141 is the same as the number of detachable guide arms 15. In this embodiment, two are set for each; the detachable guide arms 15 are connected to the detachable guide arm connecting panels 141 by bolts.

[0055] The detachable guide arm 15 includes a connecting plate 151, a connecting arm 152, and a guide horn 153 connected in sequence; the connecting plate 151 is connected to the detachable guide arm connecting panel 141 by bolts; the detachable guide arm 15 cooperates with the guide stake and guide rope to provide guidance and straightening functions for the tool;

[0056] The feed connector 13 is connected to the low-pressure wellhead or the return connector 2 to construct the circulation channel required in drilling operations.

[0057] The feed connector 13 is a sleeve structure, and its outer wall is formed from top to bottom as a locking structure, a guide double cone surface 133 and a sealing structure.

[0058] The locking structure includes multiple sets of locking units evenly distributed along the circumference. Each locking unit consists of multiple spaced upper locking bars 132. The gap between adjacent upper locking bars 132 forms an upper locking groove. The upper locking bar 132 is a horizontally placed rectangular bar structure, and the top surface of the upper locking bar 132 is an inclined surface sloping downwards towards the center of the circle. The locking structure cooperates with the connection structure of the low-pressure wellhead or reconnection joint to achieve connection and withstand tensile and bending loads during drilling.

[0059] A limiting block 131 is provided above the locking unit;

[0060] The guide double cone surface 133 is a V-groove structure composed of an upper cone surface with a gradually decreasing diameter and a lower cone surface with a gradually increasing diameter. The guide double cone surface 133 cooperates with the guide slope of the low-pressure wellhead or reconnection joint to provide guidance and straightening during the process of installing the reconnection tool at the low-pressure wellhead and connecting it to the low-pressure wellhead or reconnection joint.

[0061] The sealing structure includes at least one sealing groove 134, and a sealing ring is provided in the sealing groove 134. In this embodiment, two sealing grooves are provided, one upper and one lower. The sealing structure achieves sealing with the low-pressure wellhead or the return joint, and constructs the circulation channel required in drilling operations.

[0062] The outer wall of the feed connector 13 forms a lower anti-rotation block mounting groove, which is connected to the upper anti-rotation block mounting groove at the lower end of the body 12; the anti-rotation block 16 is placed in the upper and lower anti-rotation block mounting grooves to restrict the feed connector 13 from rotating in the vertical axis direction of the low-pressure wellhead or return connector.

[0063] The outer diameter of the sleeve coupling 11 is larger than that of the body 12; the outer diameter of the feed connector 13 is larger than that of the body 12; the inner diameters of the sleeve coupling 11, the body 12 and the feed connector 13 are the same.

[0064] The reconnection connector 2 includes an integrally formed large-diameter section 21 and a small-diameter section 22, with a smooth transition connection between the large-diameter section 21 and the small-diameter section 22;

[0065] The inner wall of the large-diameter section 21 forms, from top to bottom, a guide slope 211, a tool limiting structure, and a connecting structure 213.

[0066] The guide slope 211 is formed on the top surface of the large diameter section 21. The guide slope 211 is a downward slope from the circumference to the center. The guide slope 211 provides guidance and straightening during the connection between the main body 1 and the reconnection joint 2.

[0067] The tool limiting structure is composed of multiple tool limiting grooves 212 evenly distributed along the circumference. Each tool limiting groove 212 is a long groove with a protrusion formed on one side of its groove wall.

[0068] The protrusion of the tool limiting groove 212 cooperates with the groove wall of the tool limiting groove 212 to limit the limiting block 131. At the same time, the tool limiting groove 212 provides an assembly position for the anti-rotation block 16 when the integrated underwater low-pressure wellhead is connected to the tool.

[0069] The connection structure 213 is the same as the locking structure of the feed connector 13, and the two work together to achieve the connection between the feed connector 13 and the return connector 2.

[0070] Multiple elastic shear pin mounting holes 221 are evenly distributed along the circumference of the lower outer wall of the small diameter section 22. An elastic shear pin 3 is installed in the elastic shear pin mounting hole 221. When it is embedded in the retaining groove of the return joint of the low-pressure wellhead, it cannot be withdrawn, thus establishing a connection between the return joint and the low-pressure wellhead. When it is forcibly pulled up to a certain tension, the elastic shear pin is cut off, and the return joint is separated from the low-pressure wellhead.

[0071] The bottom outer wall of the small diameter section 22 is provided with a sealing structure, which includes at least one ring of return joint sealing groove 222. The return joint sealing groove 222 seals with the low-pressure wellhead, thus constructing the circulation channel required in drilling operations.

[0072] In this embodiment, two rings of reconnection joint sealing grooves 222 are provided, along with eight elastic shear pin mounting holes 221 and eight elastic shear pins 3.

[0073] This invention provides an integrated underwater low-pressure wellhead installation and reconnection tool that combines the functions of both a delivery tool and a reconnection tool in a single unit. This reduces the number of tools required and simplifies transportation, preparation, and maintenance. The main body 1 can be used independently, and its delivery connector enables the delivery and installation of the low-pressure wellhead, fulfilling the delivery tool function. When the main body 1 is connected to the reconnection connector 2, it functions as a reconnection tool. The reconnection connector reconnects to the low-pressure wellhead only requires downward pressure and overlift, without rotation. This reduces the requirements for the low-pressure wellhead tilt angle and platform positioning accuracy, thus lowering the operational difficulty.

[0074] Specifically: When the integrated subsea low-pressure wellhead is sent in, the sending connector 13 of the integrated subsea low-pressure wellhead installation and reconnection tool is connected to the integrated subsea low-pressure wellhead.

[0075] During connection, first align the locking structure of the insertion connector 13 with the limiting structure on the inner wall of the low-pressure wellhead connection part A1 of the integrated underwater low-pressure wellhead and the insertion connector connection structure A13, that is, align the corresponding groove and protrusion. After pressing it in, reverse the direction. At this time, the limiting block 131 is limited between the protrusion of the limiting groove A12 and the groove wall of the limiting groove A12. Then install the anti-rotation block 16 into the limiting groove A12. During separation, first remove the anti-rotation block 16, and then rotate it in the forward direction to separate.

[0076] When reconnecting the integrated subsea low-pressure wellhead, the feed connector 13 of the integrated subsea low-pressure wellhead installation reconnection tool is first connected to the reconnection connector 2, and then connected to the integrated subsea low-pressure wellhead.

[0077] During connection, the elastic shear pin 3 of the reconnector 2 engages with the reconnector limiting groove A213 of the integrated underwater low-pressure wellhead. Installation involves direct downward pressure; the elastic shear pin, with its internal spring-loaded retractable mechanism, springs out and locks into place when positioned within the reconnector limiting groove A213. For separation, lifting the pin cuts off the elastic shear pin 3, thus separating the components. Therefore, installation and retrieval do not require rotation.

[0078] The structure of the integrated subsea low-pressure wellhead used in this invention is as follows: Figure 8 , Figure 9 As shown, it includes a low-pressure wellhead connection part A1, a low-pressure wellhead functional part A2, and a low-pressure wellhead casing connection part A3, which are integrally formed from top to bottom.

[0079] The low-pressure wellhead connection part A1 is a sleeve structure, which is connected to the feed joint 13 or the reconnection joint 2 of the integrated underwater low-pressure wellhead installation and reconnection tool through various structures on the inner wall.

[0080] The inner wall of the low-pressure wellhead connection A1 is formed from top to bottom as a tool guide inclined surface A11, a limiting structure, and an insertion connector connection structure A13;

[0081] The tool guide slope A11 is formed on the top surface of the low-pressure wellhead connection part A1, and is a slope that slopes downward from the circumferential wall towards the center. The tool guide slope A11 is used to connect to the feed joint 13 or the reconnection joint 2 of the integrated underwater low-pressure wellhead installation and reconnection tool, providing guidance and straightening functions for the tool.

[0082] The limiting structure consists of multiple limiting grooves A12 evenly distributed along the circumference. Each limiting groove A12 is a rectangular groove with a protrusion on one side of its groove wall. The protrusion of the limiting groove A12 cooperates with the groove wall of the limiting groove A12 to limit the limiting block 131 of the integrated underwater low-pressure wellhead installation and reconnection tool. At the same time, the limiting groove A12 provides an assembly position for the anti-rotation block 16 when the integrated underwater low-pressure wellhead is connected to the tool.

[0083] The feed connector connection structure A13 is composed of multiple sets of connecting key units evenly distributed along the circumference; each connecting key unit includes multiple connecting keys A131 spaced apart, and the interval between adjacent connecting keys A131 forms a feed connector connection groove A132; the connecting key A131 is a horizontally placed rectangular strip structure, and the top surface of the connecting key A131 is an inclined surface sloping downward towards the center of the circle; the feed connector connection structure A13 cooperates with the locking structure of the feed connector 13 for connecting the feed connector 13 of the integrated underwater low-pressure wellhead installation and reconnection tool to the integrated underwater low-pressure wellhead.

[0084] The low-pressure wellhead functional section A2 includes a low-pressure wellhead reconnection section A21, an installation limiting section A22, and a connection transition section A23 connected sequentially from top to bottom.

[0085] Multiple guide keys A211 are evenly distributed along the circumference of the outer wall of the low-pressure wellhead return section A21. The interval between adjacent guide keys A211 forms a guide base plate heading adjustment groove A212. The guide base plate heading adjustment groove A212 cooperates with the anti-rotation block installed on the guide base plate to provide anti-rotation function in the vertical axis direction of the guide base plate. By installing the anti-rotation block in different guide base plate heading adjustment grooves A212 during installation, the heading adjustment function is realized. The guide key A211 is a long strip structure with a trapezoidal cross-section, and its top and bottom surfaces are both inclined.

[0086] The inner wall of the low-pressure wellhead reconnection section A21 forms a reconnection connector limiting groove A213; the reconnection connector limiting groove A213 is an annular groove, and its groove cross-section is a right-angled trapezoid, that is, the upper section of the reconnection connector limiting groove A213 has a uniform diameter, and the lower section gradually narrows in diameter; the reconnection connector limiting groove A213 cooperates with the elastic shear pin 3 on the reconnection connector 2. When the elastic shear pin 3 is embedded in the reconnection connector limiting groove A213, it cannot be withdrawn, thus establishing a connection between the reconnection connector 2 and the low-pressure wellhead. When forcibly lifted to a certain pulling force, the elastic shear pin 3 is cut off, and the reconnection connector 2 is separated from the low-pressure wellhead;

[0087] The outer diameter of the installation limiting section A22 is larger than the outer diameter of the low-pressure wellhead return section A21, and the inner diameter of the installation limiting section A22 is smaller than the inner diameter of the low-pressure wellhead return section A21.

[0088] The outer wall of the middle part of the installation limiting section A22 forms a plurality of bolt holes A221 evenly distributed along the circumference. The bolt holes A221 are through holes and are used to connect the lifting bolts A4 and / or the disassembly bolts A5. The lifting bolts A4 are used to lift the low-pressure wellhead during land testing, and the disassembly bolts A5 are used to compress the high-pressure wellhead outer locking ring embedded in the low-pressure wellhead, so as to separate the high-pressure wellhead from the low-pressure wellhead.

[0089] The lower outer wall of the installation limiting section A22 forms a guide base plate limiting groove A222. The guide base plate limiting groove A222 is an annular groove, which cooperates with the elastic limiting latch installed on the guide base plate to provide vertical limiting function for the guide base plate, so as to suspend the guide base plate and prevent the guide base plate from separating from the low-pressure wellhead.

[0090] The inner wall of the installation limiting section A22 forms a service tool sealing groove A223 and a high-pressure wellhead bearing ring A224; the service tool sealing groove A223 is located above the plane where the bolt hole A221 is located, and the high-pressure wellhead bearing ring A224 is located below the plane where the bolt hole A221 is located.

[0091] The service tool sealing groove A223 is an annular groove. The upper part of the service tool sealing groove A223 is completely connected to the interior of the low-pressure wellhead return section A21, and the inner wall of the low-pressure wellhead return section A21 smoothly transitions with the groove wall of the service tool sealing groove A223. The service tool sealing groove A223 cooperates with the sealing structure on the feed joint and return joint to achieve the sealing between the low-pressure wellhead and the feed joint and return joint, thus constructing the closed circulation channel required for drilling.

[0092] The high-pressure wellhead bearing ring A224 is formed at the connection between the installation limiting section A22 and the connecting transition section A23; the top surface of the high-pressure wellhead bearing ring A224 is an inclined surface that slopes downward from the circumferential wall towards the center; the high-pressure wellhead bearing ring A224 cooperates with the high-pressure wellhead to suspend the high-pressure wellhead;

[0093] The outer wall of the connecting transition section A23 gradually narrows from top to bottom; the inner diameter of the connecting transition section A23 is the same as the inner diameter of the high-pressure wellhead bearing ring A224.

[0094] The bottom of the low-pressure wellhead casing connection part A3 is a gradually narrowing slope; the outer diameter of the low-pressure wellhead casing connection part A3 matches the connecting casing.

[0095] How to use this invention:

[0096] Installation conditions, such as Figure 10 As shown, during installation, the integrated underwater low-pressure wellhead installation and reconnection tool does not include the detachable guide arm 15 and the reconnection connector 2. The specific process is as follows:

[0097] First, during land preparation or deck preparation, connect the feed joint 13 of the low-pressure wellhead installation return tool to the low-pressure wellhead, and connect the wire rope and sling to the low-pressure wellhead installation return tool and the low-pressure wellhead extension casing.

[0098] Next, the guide base plate 4 is hoisted to the small platform, and the guide piles 5 and accessories are installed;

[0099] Next, connect the lowered sleeve string and pass the sleeve through the center hole of the guide base plate 4. Use the sleeve clips to suspend the sleeve string on the turntable.

[0100] Next, using slings, the low-pressure wellhead installation and reconnection tool, the low-pressure wellhead, and the extension casing are horizontally hoisted to the catwalk. The service tool spindle is connected to the platform top drive hook. A steel wire rope is tied to the low-pressure wellhead extension casing to keep it connected to the crane hook. The top drive and the crane work together to lift the low-pressure wellhead installation and reconnection tool, the low-pressure wellhead, and the extension casing, completing the conversion of the low-pressure wellhead installation and reconnection tool, the low-pressure wellhead, and the extension casing from a horizontal to a vertical position, and connecting them to the casing suspended on the turntable.

[0101] Next, the low-pressure wellhead installation and reconnection tool and the low-pressure wellhead are lowered, so that the low-pressure wellhead passes through the rotary table to the small platform below the drilling rig, and the low-pressure wellhead is connected to the guide base plate.

[0102] Finally, after being lowered to the designated depth, the low-pressure wellhead is rotated to adjust the direction of the guide base plate, cementing is carried out for subsequent operations, and the deployed tool is rotated and retrieved according to the operational requirements.

[0103] Submarine reconnection conditions, such as Figure 11 As shown, during the reconnection process, the integrated subsea low-pressure wellhead reconnection tool installs the detachable guide arm 15 and the reconnection connector 2. The specific process is as follows:

[0104] First, install the reconnection tool at the low-pressure wellhead on the platform, and move the guide rope within the alignment range of the guide bell mouth 153 of the reconnection tool.

[0105] Next, lower the low-pressure wellhead installation reconnection tool to the vicinity of the guide pile 5, install the detachable guide arm 15 and the reconnection joint 2, check the installation status of components such as the anti-rotation block 16 and the elastic shear pin 3, and slowly lower the low-pressure wellhead installation reconnection tool so that the guide bell mouth 153 of the reconnection tool passes through the guide pile 5.

[0106] Continue lowering the low-pressure wellhead installation and reconnection tool until it enters the low-pressure wellhead. The elastic shear pin 3 installed on the low-pressure wellhead installation and reconnection tool is embedded in the reconnection joint limiting groove of the low-pressure wellhead. Raise the low-pressure wellhead installation and reconnection tool to a certain tension to confirm that the connection between the low-pressure wellhead installation and reconnection tool and the low-pressure wellhead is normal.

[0107] Finally, according to the operational requirements, the low-pressure wellhead installation and reconnection tool is lifted to cut the elastic shear pin, and the low-pressure wellhead installation and reconnection tool is retrieved.

[0108] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0109] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0110] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. An integrated subsea low pressure wellhead installation tieback tool, characterized by: The utility model relates to a kind of integrated underwater low-pressure wellheads, including main body (1) and tieback sub (2);The main body (1) includes casing collar (11), body (12) and running sub (13) connected in sequence, body (12) is externally equipped with swivel ring (14), swivel ring (14) is externally distributed with multiple detachable guide arms (15) along circumference;The running sub (13) is connected with low-pressure wellhead or tieback sub (2); The running sub (13) is sleeve structure, and its outer wall is sequentially formed with locking structure, guide double-cone surface (133) and sealing structure from top to bottom. The locking structure includes multiple groups of locking units distributed along circumference, and the locking unit is composed of multiple upper locking strips (132) arranged at intervals;The gap between adjacent upper locking strips (132) forms an upper locking groove;The upper locking strip (132) is horizontally placed in a rectangular strip structure, and the top surface of the upper locking strip (132) is an inclined surface inclined downward toward the center of the circle;A limiting block (131) is arranged above the locking unit;The locking structure cooperates with the connecting structure of the running sub connecting structure (A13) of the low-pressure wellhead or the connecting structure of the tieback sub (2) to realize connection. The tieback sub (2) includes a large-diameter section (21) and a small-diameter section (22) formed integrally;The inner wall of the large-diameter section (21) is sequentially formed with a guide inclined surface (211), a tool limiting structure and a connecting structure (213) from top to bottom;The outer wall of the lower end of the small-diameter section (22) is distributed with multiple elastic shear pin mounting holes (221) along the circumference, and an elastic shear pin (3) is arranged in the elastic shear pin mounting hole (221);When connected, the elastic shear pin (3) of the tieback sub (2) cooperates with the tieback sub limiting groove (A213) of the integrated underwater low-pressure wellhead to establish the connection between the tieback sub (2) and the low-pressure wellhead;The connecting structure (213) is the same as the locking structure of the running sub (13), and the two cooperate to realize the connection between the running sub (13) and the tieback sub (2). When installed, the integrated underwater low-pressure wellhead does not install the detachable guide arm (15) and the tieback sub (2) when installing the tieback tool. When tied back, the integrated underwater low-pressure wellhead installs the detachable guide arm (15) and the tieback sub (2) when installing the tieback tool.

2. The integrated subsea low pressure wellhead tieback tool of claim 1, wherein: The casing collar (11) is sleeve structure, and its inner wall forms casing box thread, and the casing collar (11) is connected with the pin thread of the casing through the casing box thread of its inner wall.

3. The integrated subsea low pressure wellhead tieback tool of claim 1, wherein: The body (12) is sleeve structure, and its outer wall is equipped with upper limiting ring (121) and lower limiting ring (122), and the swivel ring (14) is arranged between the upper limiting ring (121) and the lower limiting ring (122).

4. The integrated subsea low pressure wellhead tieback tool of claim 1, wherein: The outer wall of the swivel ring (14) is distributed with multiple detachable guide arm connecting panels (141) along the circumference, the number of the detachable guide arm connecting panels (141) is consistent with the number of the detachable guide arms (15), and the detachable guide arms (15) are connected with the detachable guide arm connecting panels (141) through bolts.

5. The integrated subsea low pressure wellhead tieback tool of claim 1, wherein: The detachable guide arm (15) comprises a connecting plate (151), a connecting arm (152) and a guide horn (153) connected in sequence; the connecting plate (151) is connected with the detachable guide arm connecting panel (141) by bolts.

6. The integrated subsea low pressure wellhead tieback tool of claim 1, wherein: The guide double-cone surface (133) is a V-shaped groove structure composed of an upper taper surface gradually reducing in diameter and a lower taper surface gradually increasing in diameter; the sealing structure comprises at least one sealing groove (134) in which a sealing ring is arranged.

7. The integrated subsea low pressure wellhead tieback tool of claim 1, wherein: The outer wall of the feeding joint (13) is formed with a lower anti-rotation block mounting groove, and the lower end of the body (12) is formed with an upper anti-rotation block mounting groove; the lower anti-rotation block mounting groove is communicated with the upper anti-rotation block mounting groove at the lower end of the body (12); the anti-rotation block (16) is arranged in the upper and lower anti-rotation block mounting grooves.

8. The integrated subsea low pressure wellhead tieback tool of claim 1, wherein: The guide slope (211) is formed on the top surface of the large-diameter section (21), and the guide slope (211) is a slope inclined downward from the circumferential direction to the center direction; the connecting structure (213) is the same as the locking structure of the feeding joint (13); the tool limiting structure is composed of a plurality of tool limiting grooves (212) uniformly distributed along the circumference, and the tool limiting groove (212) is a rectangular groove, and a protrusion is formed on one side groove wall.

9. The integrated subsea low pressure wellhead tieback tool of claim 1, wherein: The bottom end outer wall of the small-diameter section (22) is provided with a sealing structure, and the sealing structure comprises at least one return joint sealing groove (222).

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