Wellhead connector, mechanical unlocking tool and unlocking method thereof

Abstract

The present invention belongs to the technical field of offshore oil equipment, and discloses a wellhead connector, a mechanical unlocking tool and an unlocking method thereof. The mechanical unlocking tool is placed on the body of a Christmas tree, and the mechanical unlocking tool on the wellhead connector is locked in cooperation with a mechanical locking rod. Then, hydraulic pressure is injected into the pressurized channel of the mechanical unlocking tool through a drill pipe, and the piston body of the mechanical unlocking tool moves downward until it contacts the Christmas tree, and the lifting cylinder of the mechanical unlocking tool drives the mechanical unlocking rod to move upward, thereby realizing the mechanical unlocking of the wellhead connector.

Description

Technical Field

[0001] The invention belongs to the technical field of marine oil equipment, and in particular relates to a wellhead connector, a mechanical unlocking tool and an unlocking method thereof. Background Art

[0002] The underwater Christmas tree wellhead connector is an important component of the Christmas tree. The working performance of the wellhead connector is to connect the Christmas tree to the underwater wellhead on the seabed.

[0003] There are two main types of underwater wellhead connectors in the prior art:

[0004] One is a mechanically independent wellhead connector, such as the Chinese utility model patent with announcement number CN206309329U, which discloses a connector for an underwater wellhead and a Christmas tree, which uses a hydraulic cylinder to drive a sleeve to achieve locking or unlocking of the claws. However, the disadvantage of this wellhead connector is that a sleeve must be built in to connect the hydraulic cylinder and the claws, and movement space must be reserved for the hydraulic cylinder telescopic rod. The hydraulic cylinder is fixedly connected to the outside, which results in a large overall volume of the wellhead connector.

[0005] One is a hydraulic integrated wellhead connector, such as the Chinese invention patent with announcement number CN106837235A, which discloses a hydraulically driven claw-type underwater connector, with a cavity on the outside of the claw, the cavity is used to set a drive ring, the drive ring is located in the cavity, and hydraulic channels are provided above and below the cavity. The up and down movement of the drive ring is controlled by pressurization and decompression of the hydraulic channel, so as to achieve the locking and unlocking of the claw. Although the wellhead connector of this structure is small in size, it has high requirements for hydraulic sealing. Since the working environment of the wellhead connector is located on the seabed, it faces harsh working conditions such as waves, currents, drilling ship drift, circulating internal pressure, etc. These factors directly affect the working performance of the wellhead connector and cause the locking and unlocking functions to fail.

[0006] The Chinese invention patent, application number 201810459252.9, discloses an electric wellhead connector for an underwater all-electric Christmas tree. The technical solution adopted in this patent is to install an electric actuator system, that is, an electric cylinder to drive the drive sleeve to move up and down, thereby driving the locking and unlocking of the claws. However, the installed electric actuator system still makes the wellhead connector as a whole large and easy to fail on the seabed. Summary of the invention

[0007] In view of this, an object of the present invention is to provide a wellhead connector, a mechanical unlocking tool and an unlocking method thereof, so as to reduce the volume of the wellhead connector and ensure that the wellhead connector can be safely unlocked after failure.

[0008] The present invention solves the above technical problems through the following technical means: a wellhead connector, comprising an upper body and a lower body, and a claw slidably connected between the upper body and the lower body, an outer cylinder body is fixedly connected outside the upper body and the lower body, a cavity is enclosed between the outer cylinder body, the upper body and the lower body, a driving ring for pushing the claw to slide inward and outward is provided in the cavity, a hydraulic channel connected to the cavity for pushing the driving ring to move up and down is opened on the outer cylinder body, a mechanical unlocking rod is fixedly connected to the upper end of the driving ring, the mechanical unlocking rod extends out of the upper body, and the mechanical unlocking rod is used to lift the driving ring.

[0009] The present invention also provides a technical solution: a mechanical unlocking tool, comprising a connecting plate cooperating with a mechanical unlocking rod; and a lifting cylinder fixedly connected to the connecting plate; and a cover body fixedly connected to the lifting cylinder, a pressurized channel being provided on the cover body; and a piston body located inside the lifting cylinder, the piston body being slidably connected to the lifting cylinder, and a limiting bolt fixed on the lifting cylinder for limiting the piston body from falling out of the lifting cylinder.

[0010] The present invention also provides a technical solution, an unlocking method, comprising the following steps:

[0011] S1: Place the mechanical unlocking tool on the Christmas tree body, and lock the connecting plate and the mechanical locking rod together;

[0012] S2: Inject hydraulic pressure into the pressurized channel through the drill pipe, and the piston body moves downward until it contacts the Christmas tree. The lifting cylinder drives the mechanical unlocking rod to move upward to achieve mechanical unlocking of the wellhead connector.

[0013] The above technical solution has the following technical effects:

[0014] 1. Apply pressure from the first pressure inlet channel to push the drive ring to slide downward, and the drive ring will push the claws to move inward, so that the claws can tighten the Christmas tree and prevent the Christmas tree from detaching from the wellhead connector, thereby connecting the Christmas tree to the underwater wellhead through the wellhead connector. Apply pressure from the second pressure inlet channel to push the drive ring upward, and the drive ring will release the thrust on the claws, release the claws from locking the Christmas tree, and facilitate the removal of the Christmas tree from the wellhead connector.

[0015] Second, when the drive ring is stuck and the wellhead connector fails, the mechanical unlocking rod is lifted up by external force, which can drive the drive ring to move upward to release the clamping claw from the Christmas tree, ensuring that the Christmas tree can be safely disconnected from the wellhead connector in an emergency.

[0016] 3. When the hydraulic system inside the wellhead connector does not fail, the mechanical unlocking tool used to pull the mechanical unlocking rod is not installed on the wellhead connector, which reduces the overall size and weight of the wellhead connector and facilitates installation.

[0017] 4. Place the mechanical unlocking tool on the Christmas tree from top to bottom, and then the mechanical unlocking rod cooperates with the connecting plate, and the external drill pipe is inserted into the pressurized channel for pressurization, and a downward pressure is applied to the piston body, so that the piston body and the top of the Christmas tree located inside the lifting cylinder are always in contact, and then the lifting cylinder will slide upward relative to the piston body, thereby driving the connecting plate to pull the mechanical unlocking rod upward to achieve emergency unlocking of the wellhead connector.

[0018] 5. The mechanical unlocking tool is usually not installed on the seabed. It is only used when the hydraulic system of the wellhead connector fails and gets stuck. This ensures that the mechanical unlocking tool is not affected by the seabed environment and the mechanical unlocking tool always maintains the normal function of its parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the structure of the wellhead connector of the present invention;

[0020] Figure 2 is a top view of the wellhead connector of the present invention;

[0021] Figure 3 It is a schematic diagram of the structure of the mechanical unlocking tool of the present invention;

[0022] Figure 4 is a bottom view of the mechanical unlocking tool of the present invention;

[0023] Figure 5 is a cross-sectional view of the mechanical unlocking tool of the present invention;

[0024] Figure 6 yes Figure 5 A partial enlarged view of the middle A;

[0025] Figure 7 It is a schematic diagram of the local structure of the groove of the present invention;

[0026] Figure 8 is a top view of the mechanical unlocking tool of the present invention;

[0027] Fig. 9 yes Figure 8 Sectional view at B in the middle;

[0028] Wherein: 100-wellhead connector, 10-upper body, 20-lower body, 30-claw, 40-outer cylinder, 41-hydraulic channel, 411-first pressure inlet channel, 412-second pressure inlet channel, 50-cavity, 60-driving ring, 70-mechanical unlocking rod;

[0029] 200-mechanical unlocking tool, 210-connecting plate, 215-reinforcement plate, 220-lifting cylinder, 230-cover plate body, 231-pressurization channel, 240-piston body, 250-limit bolt, 260-guide core shaft, 261-groove, 270-shear pin, 280-limit pin, 290-proportional unloading valve, 310-control ball valve, 320-righting sleeve. DETAILED DESCRIPTION

[0030] The following describes the implementation of the present invention through specific embodiments. Those skilled in the art can understand the advantages and effects of the present invention from the contents disclosed in this specification.

[0031] Please refer to Figure 1 and Figure 2 The wellhead connector 100 includes an upper body 10 and a lower body 20, and a claw 30 slidably connected between the upper body 10 and the lower body 20. The upper body 10 and the lower body 20 are fixedly connected with an outer cylinder body 40. A cavity 50 is enclosed between the outer cylinder body 40, the upper body 10 and the lower body. A driving ring 60 for pushing the claw 30 to slide inward and outward is provided in the cavity 50. The outer cylinder body 40 is provided with a hydraulic channel 41 connected with the cavity 50 for pushing the driving ring 60 to move up and down; a mechanical unlocking rod 70 is fixedly connected to the upper end of the driving ring 60, and the mechanical unlocking rod 70 extends out of the upper body 10. The mechanical unlocking rod 70 is used to lift the driving ring 60.

[0032] During implementation, the inner wall of the upper body 10 is connected to the Christmas tree by threads, a sealing ring is embedded between the upper body 10 and the Christmas tree, and a hydraulic retraction bolt is provided to pass through the outer cylinder 40 and the upper body 10 and the sealing ring. The inner wall of the lower body 20 is connected to the underwater wellhead by threads. Sealing rings are embedded between the drive ring 60, the outer cylinder 40 and the lower body 20 to prevent pressure leakage. The hydraulic channel 41 includes a first pressure inlet channel 411 that pushes the drive ring 60 to move downward and a second pressure inlet channel 412 that pushes the drive ring 60 to move upward. The outlet of the first pressure inlet channel 411 is set above the upper end surface of the drive ring 60, and the outlet of the second pressure inlet channel 412 is set below the lower end surface of the drive ring 60. The drive ring 60 and the claw 30 are matched with an inclined surface, and the side of the claw 30 away from the drive ring 60 is provided with a tooth, and the claw 30 is used to connect with the outer wall of the Christmas tree.

[0033] During normal use, the first pressure inlet channel 411 is pressurized to push the drive ring 60 to slide downward, and the drive ring 60 will push the claw 30 to move inward, so that the claw 30 can tighten the Christmas tree and prevent the Christmas tree from being separated from the wellhead connector 100, thereby connecting the Christmas tree to the underwater wellhead through the wellhead connector 100. The second pressure inlet channel 412 is pressurized to push the drive ring 60 upward, and the drive ring 60 releases the thrust on the claw 30, releasing the locking of the claw 30 on the Christmas tree, making it easier to remove the Christmas tree from the wellhead connector 100.

[0034] When the drive ring 60 is stuck and the wellhead connector 100 fails, the mechanical unlocking rod 70 is lifted up by external force, so that the drive ring 60 can be driven to move upward to release the engagement of the claw 30 with the oil tree, thereby ensuring that the oil tree can be safely released from the wellhead connector 100 in an emergency.

[0035] In addition, in normal use, the external device for pulling the mechanical unlocking rod 70 is not installed on the wellhead connector 100, which reduces the overall volume and weight of the wellhead connector 100 and facilitates installation.

[0036] Among them, one end of the mechanical unlocking rod 70 away from the driving ring 60 is in the shape of a mushroom head.

[0037] In this way, when the wellhead connector 100 fails, it is convenient to quickly complete the effective cooperation with the mechanical unlocking rod 70 to lift the mechanical unlocking rod 70.

[0038] See also Figures 3 to 9 The mechanical unlocking tool 200 includes a connecting plate 210 that cooperates with the mechanical unlocking rod 70; a lifting cylinder 220 fixedly connected to the connecting plate 210; a cover body 230 fixedly connected to the lifting cylinder 220, and a pressurized channel 231 is provided on the cover body 230; and a piston body 240 located inside the lifting cylinder 220, the piston body 240 is slidably connected to the lifting cylinder 220, and a limiting bolt 250 fixed on the lifting cylinder 220 for limiting the piston body 240 from falling out of the lifting cylinder 220.

[0039] During implementation, the mechanical unlocking rod 70 and the connecting plate 210 are both in the shape of mushroom heads that fit each other. The mechanical unlocking tool 200 is placed on the Christmas tree from top to bottom, and then the mechanical unlocking rod 70 is inserted through a relatively large diameter hole opened on the connecting plate 210. Then, the mechanical unlocking tool 200 is rotated, and the top of the mechanical unlocking rod 70 can be locked on the connecting plate 210. When the mechanical unlocking tool 200 is placed, the piston body 240 is pushed upward, and under the action of the gravity of the piston body 240, the bottom surface of the piston body 240 is always kept in contact with the top of the Christmas tree.

[0040] In this way, by inserting an external drill pipe into the pressurized channel 231 for pressurization, a downward pressure is applied to the piston body 240, so that the piston body 240 is always in contact with the top of the oil production tree located inside the lifting cylinder 220, and then the lifting cylinder 220 will slide upward relative to the piston body 240, thereby driving the connecting plate 210 to pull the mechanical unlocking rod 70 upward, thereby realizing the emergency unlocking of the wellhead connector 100.

[0041] In addition, the mechanical unlocking tool 200 is not usually installed on the seabed. It is only used when the hydraulic system of the wellhead connector 100 fails urgently and becomes stuck, which ensures that the mechanical unlocking tool 200 is not affected by the seabed environment and the mechanical unlocking tool 200 always maintains the normal functionality of its parts.

[0042] Specifically, the diameter of the pressurized channel 231 gradually decreases from top to bottom, so that the external pressurized drill rod can be inserted into the pressurized channel 231 quickly and accurately.

[0043] Specifically, a reinforcing plate 215 is provided at the bottom of the lifting cylinder 220 , that is, at the outer side of the connecting plate 210 , for stabilizing the connecting plate 210 .

[0044] Among them, see Figure 5 and Figure 6 The mechanical unlocking tool 200 also includes a guide core shaft 260 fixedly connected to the piston body 240, the guide core shaft 260 is located on the inner side of the pressurized channel 231, the guide core shaft 260 is slidably connected to the inner side wall of the cover body 230, and a groove 261 is provided on the outer side wall of the guide core shaft 260; and a shear pin 270 passing through the cover body 230, and the shear pin 270 extends into the groove 261.

[0045] In implementation, there is one groove 261 in the form of a ring.

[0046] In this way, the piston body 240 can keep its end face parallel to the horizontal plane in the lifting cylinder 220 through the guide core shaft 260, so as to prevent the piston body 240 from tilting and getting stuck.

[0047] In addition, when the mechanical unlocking tool 200 is not in use, the end of the shear pin 270 is inserted into the upper end of the groove 261 to hook the piston body 240 and the guide mandrel 260. When the pressure is greater than the bearing pressure of the shear pin 270, the shear type fracture occurs, and the guide mandrel 260 and the piston body 240 slowly slide downward until the Christmas tree is abutted. In this solution, during the process of the mechanical unlocking tool 200 being placed on the Christmas tree, the piston body 240 is not in contact with the Christmas tree, so as to avoid the collision between the piston body 240 and the Christmas tree due to the excessive gravity of the mechanical unlocking tool 200 during placement, resulting in damage to the parts.

[0048] Among them, see Figure 7There are two grooves 261 in the guide core shaft 260, and there is a height difference between the two grooves 261, wherein the shear pin 270 extends into a groove 261 with a lower height, and a limit pin 280 extends into the other groove 261, and the limit pin 280 is fixedly connected to the cover body 230.

[0049] In this way, when the mechanical unlocking tool 200 is not in use, the end of the shear pin 270 abuts against the top of a groove 261 with a low height, and the end of the limit pin 280 is located at the bottom of a groove 261 with a high height. When pressurized, when the pressure is greater than the bearing pressure of the shear pin 270, the shear-type fracture occurs, and the guide mandrel 260 and the piston body 240 slowly slide downward until the oil tree abuts. In this process, the limit pin 280 slides upward relative to the groove 261 with a high height, and does not interfere with the travel of the guide mandrel 260 and the piston body 240. When the mechanical unlocking tool 200 is lifted out of the oil tree after use, the limit pin 280 can prevent the guide mandrel 260 and the piston body 240 from falling.

[0050] In addition, after the mechanical unlocking tool 200 has been used once, the shear pin 270 has been broken. The mechanical unlocking tool 200 is lifted out of the oil tree, and the piston body 240 is pushed upward from the inner side of the lifting cylinder 220 until the limit pin 280 abuts against the bottom end of a groove 261 with a relatively high height. The broken shear pin 270 is pulled out and a new shear pin 270 is installed to complete the replacement, thereby realizing the rapid maintenance of the mechanical unlocking tool 200.

[0051] Among them, see Figure 8 and Fig. 9 The mechanical unlocking tool 200 further includes a proportional unloading valve 290 mounted on the cover plate body 230 , and the proportional unloading valve 290 is communicated with the inner side of the lifting cylinder 220 .

[0052] In this way, through the preset pressure value of proportional unloading valve 290, when hydraulic pressure is applied from the pressure inlet channel, resulting in the downward pressure of piston body 240 being greater than the preset pressure value, proportional unloading valve 290 opens to release the pressure, thereby preventing piston body 240 from crushing the Christmas tree.

[0053] Among them, see Figure 3 and Figure 8 The mechanical unlocking tool 200 further includes a control ball valve 310 mounted on the cover plate body 230 .

[0054] In this way, when the proportional unloading valve 290 fails in the seabed environment, the control ball valve 310 can be opened manually or by a robot to release the pressure, thereby preventing the piston body 240 from crushing the Christmas tree.

[0055] Among them, see Figure 5The mechanical unlocking tool 200 also includes a straightening sleeve 320 fixed on the inner wall of the lifting cylinder 220 .

[0056] In this way, the mechanical unlocking tool 200 is kept in a vertical state during the process of being placed on the Christmas tree by the straightening sleeve 320, so that the mechanical unlocking tool 200 and the mechanical unlocking rod 70 can be quickly aligned.

[0057] In addition, when the mechanical unlocking tool 200 lifts the mechanical unlocking rod 70, the straightening sleeve 320 is filled in the gap between the lifting cylinder 220 and the Christmas tree to ensure that the lifting cylinder 220 is vertically upward in the opposite direction of the pulling force applied to the mechanical unlocking rod during this process, thereby preventing the drive ring 60 from getting stuck during this process.

[0058] The straightening sleeve 320 is made of a friction-resistant metal material.

[0059] In this way, by selecting a metal material such as high manganese steel, the mechanical unlocking tool 200 can withstand back-and-forth friction while providing support, thereby increasing the overall service life of the mechanical unlocking tool 200.

[0060] The unlocking method includes the following steps:

[0061] S1: Place the mechanical unlocking tool 200 on the Christmas tree body, and lock the connecting plate 210 with the mechanical locking rod;

[0062] S2: Inject hydraulic pressure into the pressurized channel 231 of the drill pipe, and move the piston body 240 downward until it contacts the Christmas tree. The lifting cylinder 220 drives the mechanical unlocking rod 70 to move upward, thereby achieving mechanical unlocking of the wellhead connector 100.

[0063] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention is described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solutions of the present invention, which should be included in the scope of the claims of the present invention. The technologies, shapes, and structural parts not described in detail in the present invention are all within the scope of the claims of the known technical invention. The technologies, shapes, and structural parts not described in detail in the present invention are all known technologies.

Claims

1. Mechanical unlocking tool, characterized in that: Used for a wellhead connector, the wellhead connector comprises a mechanical unlocking rod, and the end of the mechanical unlocking rod away from the driving ring is in the shape of a mushroom head; The mechanical unlocking tool comprises a connecting plate matched with the mechanical unlocking rod, the connecting plate is in the shape of a mushroom head matched with the mechanical unlocking rod, the mechanical unlocking rod can be inserted into a hole provided on the connecting plate, and the top end of the mechanical unlocking rod can be locked on the connecting plate by rotating the mechanical unlocking tool; and a lifting cylinder fixedly connected with the connecting plate; and a cover plate body fixedly connected with the lifting cylinder, a pressurizing channel being provided on the cover plate body; and a piston body located on the inner side of the lifting cylinder, the piston body being slidably connected with the lifting cylinder, and a limit bolt fixed on the lifting cylinder for limiting the piston body from falling out of the lifting cylinder; The mechanical unlocking tool also includes a guide core shaft fixedly connected to the piston body, the guide core shaft is located on the inner side of the pressurized channel, the guide core shaft is slidably connected to the inner wall of the cover body, and a groove is provided on the outer wall of the guide core shaft; and a shear pin passing through the cover body, the shear pin extending into the groove.

2. The mechanical unlocking tool according to claim 1, characterized in that: The wellhead connector includes an upper body and a lower body, and a claw slidably connected between the upper body and the lower body. An outer cylinder body is fixedly connected outside the upper body and the lower body. A cavity is enclosed between the outer cylinder body, the upper body and the lower body. A driving ring for pushing the claw to slide in and out is provided in the cavity. A hydraulic channel connected to the cavity for pushing the driving ring to move up and down is opened on the outer cylinder body; a mechanical unlocking rod for lifting the driving ring is fixedly connected to the upper end of the driving ring.

3. The mechanical unlocking tool according to claim 1, characterized in that: There are two guide core shaft grooves, and there is a height difference between the two grooves, wherein the shear pin extends into a groove with a lower height, and a limit pin extends into the other groove, and the limit pin is fixedly connected to the cover plate body.

4. The mechanical unlocking tool according to any one of claims 1 to 3, characterized in that: The mechanical unlocking tool further comprises a proportional unloading valve mounted on the cover plate body, wherein the proportional unloading valve is communicated with the inner side of the lifting cylinder.

5. The mechanical unlocking tool according to claim 4, characterized in that: The mechanical unlocking tool also includes a control ball valve mounted on the cover plate body.

6. The mechanical unlocking tool according to claim 5, characterized in that: The mechanical unlocking tool also includes a straightening sleeve fixed on the inner side wall of the lifting cylinder.

7. The mechanical unlocking tool according to claim 6, characterized in that: The straightening sleeve is made of a wear-resistant metal material.

8. The unlocking method of the mechanical unlocking tool according to any one of claims 1 to 3, characterized in that: The steps include: S1: Place the mechanical unlocking tool on the Christmas tree body, and lock the connecting plate and the mechanical unlocking rod together; S2: Inject hydraulic pressure into the pressurized channel through the drill pipe, and the piston body moves downward until it contacts the Christmas tree. The lifting cylinder drives the mechanical unlocking rod to move upward to achieve mechanical unlocking of the wellhead connector.

Images