A connector for connecting a Christmas tree body to a wellhead riser and a method of installing the same

Abstract

The application discloses a connector connecting a Christmas tree body and a wellhead riser and a mounting method thereof, which comprises a seat body, the seat body is a columnar body, a central through hole is arranged at the center of the seat body, the upper part of the central through hole is fixedly connected with the Christmas tree body through a connecting device, the lower part of the central through hole is movably connected with the wellhead riser through a locking assembly, the locking assembly comprises annularly arranged locking blocks, elastic components are arranged between two adjacent locking blocks, the elastic components make the locking blocks expand on the hole wall of the central through hole, a driving ring is slidably sleeved in the central through hole, a first oil cavity is formed between the upper end of the driving ring and the seat body, an insertion part is arranged at the lower end of the driving ring, when hydraulic oil is injected into the first oil cavity, the driving ring slides axially downwards along the central through hole, the insertion part is inserted into the gap between the locking assembly and the central through hole, the locking blocks are inwards retracted, and the wellhead riser is connected. The application has the advantages of simple structure, convenient operation, easy control, high locking connection strength and the like.

Description

A connector for connecting the wellhead tree body and the wellhead riser and its installation method. Technical Field

[0001] This invention belongs to the field of petroleum extraction technology, and in particular relates to a connector for connecting the wellhead tree body and the wellhead riser and its installation method. Background Technology

[0002] A wellhead is a type of wellhead device used in subsea oil and gas field development. Its function is equivalent to an underwater transfer platform for oil transportation, enabling functions such as monitoring oil volume, oil pressure, cable crossing, chemical injection, and process monitoring.

[0003] The connector is the pipeline joint for underwater installation of the Christmas tree, and its function is to connect the wellhead riser and the Christmas tree body. In practical applications, the connector is first connected to the Christmas tree body on the surface, and then the Christmas tree is lowered underwater so that the connector mates with the wellhead riser, thus completing the Christmas tree installation.

[0004] In the existing technology, the connection structure between the connector and the wellhead riser mainly uses mechanical or hydraulic jaws to achieve radial locking. However, whether it is mechanical or hydraulic, the jaws and the power source are connected by a connecting rod or rocker arm, which has problems such as structural redundancy, high complexity of locking operation, and insufficient locking strength. Summary of the Invention

[0005] The problem to be solved by the present invention is to provide a connector for connecting the Christmas tree body and the wellhead riser and its installation method, especially a connector with simple structure, convenient operation, firm connection with the Christmas tree body and the wellhead riser, and high locking reliability.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a connector for connecting the Christmas tree body and the wellhead riser, comprising a base body, the base body being cylindrical, a central through hole being provided at the center of the base body, the upper part of the central through hole being fixedly connected to the Christmas tree body through a connecting device, and the lower part of the central through hole being movably connected to the wellhead riser through a locking assembly, the locking assembly comprising locking blocks arranged in a ring array, an elastic component being provided between two adjacent locking blocks, the elastic component causing the locking blocks to expand on the wall of the central through hole, a drive ring being slidably sleeved inside the central through hole, the upper end of the drive ring and the base body forming a first oil cavity, the lower end of the drive ring being provided with an insertion part, when hydraulic oil is injected into the first oil cavity, the drive ring slides down along the central through hole axially, the insertion part is inserted into the gap between the locking assembly and the central through hole, causing the locking blocks to retract inward and connect with the wellhead riser.

[0007] Furthermore, the locking block is an arc-shaped block with a boss at the bottom of the inner arc surface and an annular groove at the outer edge of the top of the wellhead riser. The boss and the annular groove cooperate to achieve a tight connection between the connector and the wellhead riser. Both ends of the locking block are provided with mounting holes. The elastic component is a disc spring with support shafts at both ends, and the support shafts are placed in the mounting holes.

[0008] Furthermore, the central through hole wall is provided with a first step portion, which is placed between the connecting device and the drive ring, and the first step portion and the top surface of the drive ring together form the first oil cavity.

[0009] Furthermore, the top of the seat is provided with a vertically oriented oil passage, which connects to the outside and the first oil cavity, and the upper part of the seat is provided with a horizontally oriented branch passage, which connects to the outside and the oil passage.

[0010] Furthermore, the seat body is provided with an annular groove located below the first oil cavity. The diameter of the annular groove is larger than the diameter of the first oil cavity. The drive ring is provided with a support piece that protrudes radially outward in the middle. The support piece is placed in the annular groove. The lower side of the support piece is connected to the upper surface of the push block. The push block is slidably installed in the annular groove. The push block and the annular groove form a second oil cavity.

[0011] Furthermore, a second step is provided on the wall of the central through hole, the second step is positioned directly above the annular groove, a traction rod is fixedly connected to the upper surface of the support plate, the traction rod passes vertically upward through the second step and exits the seat body, and the traction rod is slidably connected to the seat body.

[0012] Furthermore, the insertion part is a guide slope structure, and the upper end of the locking block and the lower end of the driving ring are both provided with mutually cooperating guide slopes.

[0013] Furthermore, the connecting device has a threaded structure. The upper part of the central through hole is provided with a first internal thread, and the oil production tree body is provided with an external thread. The external thread engages with the first internal thread to achieve a tight connection between the connector and the upper part of the oil production tree body. A locking ring is installed inside the drive ring. The locking ring slides with the drive ring. The inner wall of the locking ring is provided with a second internal thread. The external thread engages with the second internal thread to achieve a tight connection between the connector and the lower part of the oil production tree body.

[0014] Furthermore, the inner wall of the locking ring is provided with a strip groove. When the tree body is placed inside the locking ring, a flat key is inserted into the strip groove to prevent relative rotation between the tree body and the locking ring.

[0015] Furthermore, the present invention also provides a connector installation method for connecting the Christmas tree body and the wellhead riser, which includes the following steps using the aforementioned connector for connecting the Christmas tree body and the wellhead riser.

[0016] S1: Connect the wellhead body and the connector via a connecting device;

[0017] S2: Lower the assembled tree body and connector as a whole to the wellhead riser;

[0018] S3: After the wellhead riser extends into the central area enclosed by the locking assembly, hydraulic oil is injected into the first oil chamber through the hydraulic system. The hydraulic oil pushes the drive ring to slide downward along the central through hole. The lower end of the drive ring is inserted into the gap between the locking assembly and the central through hole, forcing each locking block to overcome the resistance of the elastic component and retract inward. The boss of the locking block is embedded in the annular groove of the wellhead riser, realizing the connection between the production tree body and the wellhead riser.

[0019] The advantages and positive effects of this invention are:

[0020] 1. When using this invention, the wellhead riser is inserted into the central hole formed by the locking assembly. Under the push of hydraulic oil, the drive ring slides downward, forcing the locking assembly to overcome the resistance of the elastic component and retract inward. This causes the boss of the locking block to fix the wellhead riser onto the connector, thereby realizing the docking and installation of the wellhead riser and the production tree body. The locking assembly is controlled to clamp the wellhead riser through the above-mentioned driving method. It has the advantages of simple structure, convenient operation, easy control, and high locking connection strength.

[0021] 2. The Christmas tree connector provided by this invention is equipped with a three-level unlocking method with the wellhead riser. The first two levels are hydraulically driven, and the third level is mechanically controlled. Since the Christmas tree body and connector are often underwater, they are prone to damage and have a high failure rate. Multiple unlocking methods ensure successful disassembly of the connector from the wellhead riser. Attached Figure Description

[0022] Figure 1 is a schematic diagram of the overall structure of an embodiment of the present invention.

[0023] Figure 2 is a schematic diagram of the usage state of an embodiment of the present invention.

[0024] Figure 3 is an exploded schematic diagram of the locking assembly according to an embodiment of the present invention.

[0025] Figure 4 is a schematic diagram of the drive ring structure according to an embodiment of the present invention.

[0026] Figure 5 is a process flow diagram of another embodiment of the present invention.

[0027] In the picture:

[0028] 1. Base 1-1, Central through hole 1-2, Annular groove

[0029] 1-3, Oil passage; 1-4, Branch passage; 1-5, Support platform

[0030] 1-6, First internal thread; 1-7, First oil cavity; 1-8, First step portion

[0031] 1-9, Second oil cavity; 1-10, Second step section; 1-11, Chamber;

[0032] 2. Locking assembly 2-1, locking block 2-1-1, mounting hole

[0033] 2-1-2, boss 2-2, elastic component 2-2-1, support shaft;

[0034] 3. Drive ring 3-1, support plate 3-2, guide slope

[0035] 3-3, pores; 3-4, thickened section;

[0036] 4. Towing rod 4-1, pull ring;

[0037] 5. Locking ring 5-1, strip groove 5-2, second internal thread;

[0038] 6. Push the block;

[0039] 7. The oil well tree itself;

[0040] 8. Wellhead riser. Detailed Implementation

[0041] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. 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.

[0042] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for 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. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0043] 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 can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0044] The embodiments of the present invention will be further described below with reference to the accompanying drawings:

[0045] As shown in Figure 1, a connector for connecting the Christmas tree body and the wellhead riser includes a base 1, which is a cylindrical body. Preferably, the base 1 provided in this embodiment is an annular cylinder. A central through hole 1-1 is provided at the center of the base 1, which penetrates the axial direction of the base 1. The upper part of the central through hole 1-1 is fixedly connected to the Christmas tree body 7 through a connecting device, and the lower part of the central through hole 1-1 is movably connected to the wellhead riser 8 through a locking assembly 2.

[0046] The connecting device is used to connect the tree trunk body 7 and the connector. The connecting device can have various structures, as long as it achieves the above functions. Specifically, as shown in Figure 2, the connecting device provided in this embodiment is a threaded structure. A first internal thread 1-6 is provided on the upper part of the central through hole 1-1, and an external thread is provided on the tree trunk body 7. The external thread mates with the first internal thread 1-6 to achieve a tight connection between the connector and the upper part of the tree trunk body 7. A drive ring 3 is slidably sleeved inside the central through hole 1-1. A locking ring 5 is installed inside the drive ring 3, and the locking ring 5 slidably mates with the drive ring 3. A second internal thread 5-2 is provided on the inner wall of the locking ring 5, and the external thread mates with the second internal thread 5-2 to achieve a tight connection between the connector and the lower part of the tree trunk body 7. Preferably, the inner wall of the locking ring 5 is provided with a strip groove 5-1 extending in the vertical direction. After the oil tree body 7 is screwed into the locking ring 5 by external thread, a flat key is inserted into the strip groove 5-1 to prevent relative rotation between the oil tree body 7 and the locking ring 5, so that the oil tree body 7 is more reliably fixed in the connector.

[0047] The locking assembly 2 is a device for locking and unlocking the connector and the wellhead riser 8. The locking assembly 2 can have various structures, as long as it achieves the above-mentioned functions. Specifically, as shown in Figure 3, the locking assembly 2 provided in this embodiment includes several locking blocks 2-1 arranged in a ring array. An elastic component 2-2 is provided between any two adjacent locking blocks 2-1. The elastic component 2-2 applies a pushing force to the locking blocks 2-1. Under the action of this pushing force, each locking block 2-1 is in contact with the wall of the central through hole 1-1, that is, the locking assembly 2 is in an expanded state. At this time, the inner diameter of the locking assembly 2 is at its maximum value. Preferably, the locking block 2-1 is arc-shaped. A boss 2-1-2 is provided at the bottom of the inner arc surface of the locking block 2-1. An annular groove is provided on the outer edge of the top of the wellhead riser 8. The boss 2-1-2 cooperates with the annular groove to achieve a tight connection between the connector and the wellhead riser 8. The locking block 2-1 has mounting holes 2-1-1 on both ends. The elastic component 2-2 is a disc spring, and the disc spring has support shafts 2-2-1 on both ends. The support shafts 2-2-1 are placed inside the mounting holes 2-1-1. Preferably, a support platform 1-5 is provided at the lower part of the central through hole 1-1, and the locking assembly 2 is placed on the support platform 1-5.

[0048] As shown in Figure 1, a drive ring 3 is slidably sleeved within the central through hole 1-1. The drive ring 3 can slide up and down within the central through hole 1-1. A first step portion 1-8 is provided on the wall of the central through hole 1-1, and the first step portion 1-8 is placed between the connecting device and the drive ring 3, as shown in Figure 4. A thickened portion 3-4 is provided at the upper end of the drive ring 3, and a first oil cavity 1-7 is formed between the first step portion 1-8 and the thickened portion 3-4. An insertion portion is provided at the lower end of the drive ring 3. When hydraulic oil is injected into the first oil cavity 1-7, the drive ring 3 slides down axially along the central through hole 1-1, and the insertion portion is inserted into the gap between the locking assembly 2 and the central through hole 1-1, so as to force the locking assembly 2 to overcome the resistance of the elastic component 2-2 and contract inward, connecting with the wellhead riser 8.

[0049] Specifically, the insertion part is a guide slope structure, and the upper end of the locking block 2-1 and the lower end of the drive ring 3 are provided with mutually cooperating guide slopes 3-2.

[0050] The Christmas tree connector provided by this invention is configured with a three-level unlocking method with the wellhead riser 8. The first two levels are hydraulically driven, and the third level is mechanically controlled. Since the Christmas tree body 7 and the connector are constantly underwater, they are prone to damage and have a high failure rate. Multiple unlocking methods ensure that the connector can be successfully disassembled from the wellhead riser 8.

[0051] To facilitate the supply and discharge of hydraulic oil to and from the first oil chamber 1-7, specifically as shown in Figure 1, the top of the base 1 is provided with a vertically oriented oil passage 1-3, which connects the outside to the first oil chamber 1-7. The upper part of the base 1 is provided with a horizontally oriented branch passage 1-4, which connects the outside to the oil passage 1-3. The oil passage 1-3 is used to supply oil to the first oil chamber 1-7, and the branch passage 1-4 is used to discharge the hydraulic oil from the first oil chamber 1-7.

[0052] Specifically, the hydraulic system draws out hydraulic oil from the first oil chamber 1-7 through the branch channel 1-4. Under negative pressure, the drive ring 3 slides upward along the central through hole 1-1. When the lower end of the drive ring 3 completely leaves the gap between the locking assembly 2 and the central through hole 1-1, the elastic component 2-2 deforms the locking assembly 2 into an expanded state again. The boss 2-1-2 of the locking block 2-1 disengages radially from the annular groove 1-2 of the wellhead riser 8, thereby realizing the separation of the production tree body 7 from the wellhead riser 8.

[0053] To prevent the above unlocking methods from failing and causing disassembly failure during the unlocking process, this embodiment also integrates two other unlocking methods on the connector, as follows:

[0054] As shown in Figure 1, the seat 1 has an annular groove 1-2 located below the first oil cavity 1-7. The diameter of the annular groove 1-2 is larger than the diameter of the first oil cavity 1-7. As shown in Figure 4, the drive ring 3 has a support plate 3-1 that protrudes radially outward in the middle. The support plate 3-1 is placed in the annular groove 1-2. The lower side of the support plate 3-1 is connected to the upper surface of the push block 6. The push block 6 is slidably installed in the annular groove 1-2. The push block 6 can be slidably installed in the annular groove 1-2. The push block 6 and the annular groove 1-2 form a second oil cavity 1-9.

[0055] Based on this, when the first oil chamber 1-7 fails and cannot be unlocked, hydraulic oil can be injected into the second oil chamber 1-9, and the push block 6 and the support plate 3-1 will push the drive ring 3 upward to slide in the opposite direction, thereby unlocking.

[0056] A second step 1-10 is provided on the wall of the central through hole 1-1, positioned directly above the annular groove 1-2. A traction rod 4 is fixedly connected to the upper surface of the support plate 3-1, and the traction rod 4 passes vertically upward through the second step 1-10 and exits the seat 1, slidably connected to the seat 1. A pull ring 4-1 is provided at the top of the traction rod 4. Based on this, when both the first oil chamber 1-7 and the second oil chamber 1-9 fail and cannot be unlocked, the traction rod 4 can be pulled by mechanical traction, forcing the drive ring 3 to slide upward, thereby achieving unlocking.

[0057] As shown in Figure 4, the support plate 3-1 is provided with air holes 3-3. When the mechanical pull of the traction rod 4 is performed, as the drive ring 3 moves upward, a chamber 1-11 will be formed between the push block 6 and the drive ring 3. This chamber 1-11 will generate negative pressure to hinder the support plate 3-1 from moving upward. Therefore, the setting of air holes 3-3 can prevent the chamber 1-11 from generating negative pressure and ensure that the drive ring 3 and the traction rod 4 can move upward smoothly.

[0058] As shown in Figure 5, the present invention also provides a connector installation method for connecting the Christmas tree body and the wellhead riser. The method utilizes the aforementioned connector for connecting the Christmas tree body and the wellhead riser, and includes the following steps:

[0059] S1: Connect the Christmas tree body 7 to the connector via a connecting device. Specifically, when installing the Christmas tree body 7 on the ground, the lower end of the Christmas tree body 7 extends into the central through hole 1-1, and is then threaded onto the inner wall of the locking ring 5, fixing the lower end of the Christmas tree body 7 inside the connector, and fixing the upper end of the Christmas tree body 7 to the internal thread at the top of the connector.

[0060] S2: Lower the assembled tree body 7 and connector as a whole to the wellhead riser 8;

[0061] S3: After the wellhead riser 8 extends into the central area enclosed by the locking assembly 2, hydraulic oil is injected into the first oil chamber 1-7 through the hydraulic system. The hydraulic oil pushes the drive ring 3 to slide downward along the central through hole 1-1. The lower end of the drive ring 3 is inserted into the gap between the locking assembly 2 and the central through hole 1-1, forcing each locking block 2-1 to overcome the resistance of the elastic component 2-2 and contract inward. The boss 2-1-2 of the locking block 2-1 is embedded in the annular groove 1-2 of the wellhead riser 8, realizing the connection between the production tree body 7 and the wellhead riser 8.

[0062] The advantages and positive effects of this invention are:

[0063] 1. When using this invention, the wellhead riser is inserted into the central hole formed by the locking assembly. Under the push of hydraulic oil, the drive ring slides downward, forcing the locking assembly to overcome the resistance of the elastic component and retract inward. This causes the boss of the locking block to fix the wellhead riser onto the connector, thereby realizing the docking and installation of the wellhead riser and the production tree body. The locking assembly is controlled to clamp the wellhead riser through the above-mentioned driving method. It has the advantages of simple structure, convenient operation, easy control, and high locking connection strength.

[0064] 2. The Christmas tree connector provided by this invention is equipped with a three-level unlocking method with the wellhead riser. The first two levels are hydraulically driven, and the third level is mechanically controlled. Since the Christmas tree body and connector are often underwater, they are prone to damage and have a high failure rate. Multiple unlocking methods ensure successful disassembly of the connector from the wellhead riser.

[0065] The embodiments of the present invention have been described in detail above, but the content described is only a preferred embodiment of the present invention and should not be considered as limiting the scope of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the patent coverage of the present invention.

Claims

1. A connector for connecting the wellhead tree body and the wellhead riser, characterized in that: The system includes a base, which is cylindrical in shape. A central through-hole is located at the center of the base. The upper part of the central through-hole is fixedly connected to the wellhead tree body via a connecting device. The lower part of the central through-hole is movably connected to the wellhead riser via a locking assembly. The locking assembly includes locking blocks arranged in a ring array. An elastic component is provided between adjacent locking blocks, allowing the locking blocks to expand against the wall of the central through-hole. A drive ring is slidably fitted inside the central through-hole. The upper end of the drive ring and the base form a first oil cavity. The lower end of the drive ring has an insertion part. When hydraulic oil is injected into the first oil chamber, the drive ring slides down axially along the central through hole, and the insertion part is inserted into the gap between the locking assembly and the central through hole, causing the locking block to retract inward and connect with the wellhead riser. The locking block is arc-shaped, with a boss at the bottom of the inner arc surface and an annular groove at the outer edge of the top of the wellhead riser. The boss and the annular groove cooperate to achieve a tight connection between the connector and the wellhead riser. Both ends of the locking block have mounting holes. The elastic component is a disc spring. Each component is provided with a support shaft, which is placed inside the mounting hole. The wall of the central through hole has a first step, which is placed between the connecting device and the drive ring. The first step and the top surface of the drive ring together form the first oil cavity. The top of the seat has a vertically oriented oil passage, which connects to the outside and the first oil cavity. The upper part of the seat has a horizontally oriented branch passage, which connects to the outside and the oil passage. The seat has an annular groove located below the first oil cavity, and the diameter of the annular groove is larger than the diameter of the first oil cavity. The middle part of the drive ring has a support piece that protrudes radially outward, which is placed inside the annular groove. The lower side of the support piece is connected to the upper surface of a push block, which is slidably installed in the annular groove. The push block and the annular groove form a second oil cavity. The wall of the central through hole has a second step, which is placed directly above the annular groove. The upper surface of the support piece is fixedly connected to a traction rod, which passes vertically upward through the second step and exits the seat. The traction rod is slidably connected to the seat.

2. The connector for connecting the wellhead tree body and the wellhead riser according to claim 1, characterized in that: The insertion part is a guide slope structure, and the upper end of the locking block and the lower end of the driving ring are both provided with mutually cooperating guide slopes.

3. A connector for connecting the wellhead tree body and the wellhead riser according to claim 1 or 2, characterized in that: The connecting device has a threaded structure. The upper part of the central through hole is provided with a first internal thread, and the oil production tree body is provided with an external thread. The external thread engages with the first internal thread to achieve a tight connection between the connector and the upper part of the oil production tree body. A locking ring is installed inside the drive ring. The locking ring slides with the drive ring. The inner wall of the locking ring is provided with a second internal thread. The external thread engages with the second internal thread to achieve a tight connection between the connector and the lower part of the oil production tree body.

4. A connector for connecting the wellhead tree body and the wellhead riser according to claim 3, characterized in that: The inner wall of the locking ring is provided with a strip groove. When the tree body is placed in the locking ring, a flat key is inserted into the strip groove to prevent relative rotation between the tree body and the locking ring.

5. A method for installing a connector connecting the Christmas tree body and the wellhead riser, utilizing the connector for connecting the Christmas tree body and the wellhead riser as described in any one of claims 1 to 4, characterized in that: The process includes the following steps: S1: Connecting the Christmas tree body and the connector via a connecting device; S2: Lowering the assembled Christmas tree body and the connector as a whole to the wellhead riser; S3: After the wellhead riser extends into the central area enclosed by the locking assembly, hydraulic oil is injected into the first oil chamber through the hydraulic system. The hydraulic oil pushes the drive ring to slide downward along the central through hole. The lower end of the drive ring is inserted into the gap between the locking assembly and the central through hole, forcing each locking block to overcome the resistance of the elastic component and retract inward. The protrusion of the locking block is embedded in the annular groove of the wellhead riser, thereby connecting the Christmas tree body and the wellhead riser.

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