Coiled tubing completion connector

Abstract

The utility model relates to oil and gas collection technical field, especially to a coiled tubing completion connector, include: the upper joint, its upper end is connected with the completion well mouth hanger, its inside is equipped with sealing structure, the connector body is connected with the lower extreme of upper joint, metal sealing structure is equipped between upper joint and connector body, and first locking mechanism, including the depression cap and the taper slip of setting in the depression cap, the depression cap is connected with the connector body. The utility model discloses through the design composite sealing structure including metal sealing structure, has guaranteed the overall sealing property of coiled tubing completion connector, solved the problem that the traditional sealing ring structure leaks under the high temperature, high pressure and corrosion environment because the sealing ring is easy to age failure, makes coiled tubing completion connector applicable to the oil and gas production environment of high temperature, high pressure and having corrosion, ensures long -term reliable operation.

Description

Technical Field

[0001] This utility model relates to the field of oil and gas extraction technology, and in particular to a coiled tubing completion connector. Background Technology

[0002] With the progress of oilfield exploration and development, various new technologies and products are rapidly developing. The application of coiled tubing technology in oil exploration and development is increasing, and the use of coiled tubing is becoming more and more common. Coiled tubing technology has advantages such as fast operation speed, less preparation time for the well site, fewer equipment, and shorter relocation and installation time; high construction efficiency, enabling rapid running and pulling of coiled tubing, pressure testing at any time, and continuous operation throughout the entire process; it can be carried out under harsh production conditions with fewer construction personnel; it is safe and reliable, allowing continuous operation under pressure without blowout or pressure release; it reduces reservoir pollution, protects the environment, and avoids formation damage caused by well control.

[0003] Because of the advantages mentioned above, coiled tubing is now used to complete many conventional construction procedures, reducing the labor intensity of construction workers, increasing speed and efficiency, and enabling some unconventional pressurized operations. Coiled tubing is not only used for construction operations; it is also increasingly being used for some well completion production strings. This requires the design of special equipment and tools to facilitate the transition of coiled tubing from its operational state to its production state, transforming it from a moving work string to a stationary production string. Unlike conventional tubing, coiled tubing is made from a long steel strip, rolled and welded to create a highly resilient and pressure-resistant steel tubing. The tubing itself has no threads or couplings, making conventional threaded connections impossible. Therefore, a coiled tubing completion connector is needed to connect the end of the coiled tubing to the threaded lower end of the wellhead hanger, bearing the weight of the coiled tubing suspended in the well for well completion production and withstanding the high pressure inside the well, providing a production channel for oil and gas.

[0004] Existing coiled tubing completion connectors have a locking mechanism at the bottom for locking the coiled tubing and a thread at the top for connecting to the completion wellhead hanger. However, because they only have a common sealing structure on the outside of the coiled tubing, although they enhance the sealing effect by setting multiple sealing rings, there is still a risk of leakage due to the sealing rings aging and failing in the high temperature, high pressure and corrosive environment of oil and gas extraction. Utility Model Content

[0005] The purpose of this utility model is to provide a coiled tubing completion connector. By designing a composite sealing structure that includes a metal sealing structure, the overall sealing performance of the coiled tubing completion connector is guaranteed, making it suitable for high-temperature, high-pressure, and corrosive oil and gas production environments, and ensuring long-term reliable operation.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A coiled tubing completion connector, comprising: The upper connector is connected to the wellhead hanger at its upper end, and its inner side is equipped with a sealing structure. The connector body is connected to the lower end of the upper connector. A metal sealing structure is provided between the upper connector and the connector body. The metal sealing structure includes a pressure ring and a metal sealing ring. The pressure ring can compress the metal sealing ring to deform it. The first locking mechanism includes a lower pressure cap and a conical collet disposed inside the lower pressure cap. The inner side of the lower pressure cap is provided with a conical surface structure that mates with the conical collet. The lower pressure cap is connected to the connector body. The upper connector, the connector body, and the lower pressure cap all have a cylindrical hollow structure for inserting continuous tubing.

[0007] In one embodiment, the contact surface between the pressure ring and the metal sealing ring is provided with an annular protrusion, and the contact surface between the metal sealing ring and the pressure ring is provided with an annular groove that mates with the annular protrusion.

[0008] In one embodiment, the pressure ring includes an upper pressure ring and a lower pressure ring, which are respectively disposed on the upper and lower sides of the metal sealing ring, and an annular deformation groove is provided in the middle of both the inner and outer sides of the metal sealing ring.

[0009] In one embodiment, the sealing structure includes at least two sealing ring grooves for placing sealing rings.

[0010] In one embodiment, the sealing ring is made of fluororubber.

[0011] In one embodiment, a first retaining ring is provided between the connector body and the metal sealing structure, the first retaining ring being capable of axially compressing the metal sealing structure; a second retaining ring is provided between the connector body and the tapered slip, the second retaining ring being capable of axially compressing the tapered slip.

[0012] In one embodiment, the connector body has at least two relatively parallel first clamping planes on the side near the upper connector end, at least two relatively parallel second clamping planes on the side near the lower cap end, and at least two relatively parallel third clamping planes on the side of the lower cap.

[0013] In one embodiment, the coiled tubing completion connector further includes a second locking mechanism, which is a rivet-type locking mechanism disposed on the connector body. The connector body has a threaded hole for installing a threaded rivet, and the coiled tubing has a pre-set recess for engaging the threaded rivet.

[0014] In one embodiment, multiple sets of threaded hole groups are provided at axial intervals along the connector body. Each threaded hole group includes a plurality of threaded holes evenly distributed circumferentially along the connector body. Adjacent threaded hole groups are arranged equidistantly at a 30° right-hand helical angle to form a spirally distributed array of threaded holes.

[0015] In one embodiment, the conical slip has a plurality of slip flaps along its circumference, and slip teeth are provided on the inner side of each slip flap.

[0016] Compared with the prior art, the advantages of this utility model are: This invention, through the design of a composite sealing structure including a metal sealing structure, ensures the overall sealing performance of the coiled tubing completion connector. It solves the problem of leakage caused by the easy aging and failure of the sealing ring in traditional sealing ring structures under high temperature, high pressure and corrosive environments. This makes the coiled tubing completion connector suitable for high temperature, high pressure and corrosive oil and gas production environments, ensuring long-term reliable operation. Attached Figure Description

[0017] The present invention will be described in more detail below based on embodiments and with reference to the accompanying drawings.

[0018] Figure 1 A schematic diagram of the structure of the coiled tubing completion connector provided by this utility model; Figure 2 An exploded view of the coiled tubing completion connector provided by this utility model; Figure 3 for Figure 2 Cross-sectional view of section AA; Figure 4 for Figure 2 Cross-sectional view of section BB in the middle; Figure 5 for Figure 2 Cross-sectional view of section CC; Figure 6 for Figure 2 Cross-sectional view of section DD; Figure 7 for Figure 2 A magnified view of a section at point E in the middle; Figure 8A schematic diagram of the connection structure between the coiled tubing completion connector and the coiled tubing provided by this utility model; Figure 9 for Figure 8 A magnified view of a section at point F in the middle; Figure 10 This is a schematic diagram of the wellhead hanger for well completion.

[0019] Figure label: 1. Upper connector; 1-1. Sealing ring groove; 1-2. Sealing ring; 2. Upper pressure ring; 2-1. Annular protrusion; 3. Metal sealing ring; 3-1. Annular groove; 3-2. Annular deformation groove; 4. Lower pressure ring; 5. First retaining ring; 6. Connector body; 6-1. First clamping plane; 6-2. Threaded hole; 6-3. Second clamping plane; 7. Second retaining ring; 8. Conical slip; 8-1. Slip teeth; 9. Lower pressure cap; 9-1. Third clamping plane; 10. Coiled tubing; 11. Wellhead hanger for completion; 11-1. Connecting thread. Detailed Implementation

[0020] The technical solution of this utility model 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 this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0021] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model 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 this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0022] In the description of this utility model, 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; they can also refer to the internal connection of two components; and they can refer to a wireless connection or a wired connection. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0023] Furthermore, the technical features involved in the different embodiments of this utility model described below can be combined with each other as long as they do not conflict with each other.

[0024] The purpose of this utility model is to provide a coiled tubing completion connector. By designing a metal sealing structure, the overall sealing performance of the coiled tubing completion connector is guaranteed, making it suitable for high-temperature, high-pressure, and corrosive oil and gas production environments, and ensuring long-term reliable operation.

[0025] To achieve the above objectives, the present invention adopts the following technical solution: like Figures 1-10 As shown, a coiled tubing completion connector includes: an upper connector 1, a connector body 6, and a first locking mechanism. The upper end of the upper connector 1 is connected to the completion wellhead hanger 11, and the upper end of the upper connector 1 is provided with a thread for connection to the connecting thread 11-1 of the completion wellhead hanger 11, as shown. Figure 10 As shown, the connecting thread 11-1 of the wellhead hanger 11 is an internal thread, while the thread on the upper connector 1 is an external thread. A sealing structure is provided on the inner side of the upper connector 1. The connector body 6 is connected to the lower end of the upper connector 1, and the connector body 6 is threadedly connected to the upper connector 1. A metal sealing structure is provided between the upper connector 1 and the connector body 6. The metal sealing structure includes a pressure ring and a metal sealing ring 3. When the connector body 6 and the upper connector 1 are tightened, the pressure ring compresses the metal sealing ring 3, causing it to deform. The inner surface of the metal sealing ring 3 presses against the outer wall of the coiled tubing 10, achieving a seal. The metal sealing ring 3 is made of soft metal, preferably brass. The first locking mechanism includes a lower pressure cap 9 and a conical slip 8 disposed inside the lower pressure cap 9. The inner side of the lower pressure cap 9 has a conical surface structure that mates with the conical slip 8. The lower pressure cap 9 is connected to the connector body 6, and the lower pressure cap 9 is threadedly connected to the connector body 6. The upper connector 1, the connector body 6, and the lower pressure cap 9 all have a cylindrical hollow structure for inserting the coiled tubing 10.

[0026] like Figure 9As shown, an annular protrusion 2-1 is provided on the contact surface between the pressure ring and the metal sealing ring 3, and an annular groove 3-1 that mates with the annular protrusion 2-1 is provided on the contact surface between the metal sealing ring 3 and the pressure ring. By setting the mutually mating annular protrusion 2-1 and annular groove 3-1, the metal sealing ring 3 can easily undergo radial deformation, thereby pressing the outer wall of the continuous oil pipe 10 to achieve sealing.

[0027] Specifically, such as Figure 9 As shown, the pressure ring includes an upper pressure ring 2 and a lower pressure ring 4. The upper pressure ring 2 and the lower pressure ring 4 are respectively disposed on the upper and lower sides of the metal sealing ring 3. The inner and outer sides of the metal sealing ring 3 are provided with annular deformation grooves 3-2. By providing annular deformation grooves 3-2, it is more conducive to the metal sealing ring 3 to produce radial deformation when subjected to extrusion pressure at both ends. Figure 9 This indicates the structural state of the metal sealing ring 3 when the connector body 6 and the upper connector 1 are not yet tightened, and there is still a gap between the metal sealing ring 3 and the continuous oil pipe 10.

[0028] Preferred, such as Figure 1 and Figure 8 As shown, the inner side of the upper connector 1 is provided with at least two sealing ring grooves 1-1 for placing the sealing rings 1-2. The sealing rings 1-2 are made of fluororubber, which has the characteristics of high temperature resistance, high pressure resistance, and corrosion resistance, making it suitable for high-temperature, high-pressure, and corrosive oil and gas production environments. The mating surfaces between the upper connector 1 and the metal sealing ring 3 are designed with a high-gloss finish to ensure a close fit between the upper connector 1 and the metal sealing ring 3, which is beneficial for withstanding high pressure. Compared with the rubber materials commonly used in traditional sealing rings, the metal material is more resistant to high temperature, high pressure, and corrosion. By setting a composite sealing structure, that is, by setting a metal sealing structure and a sealing ring sealing structure, the connection sealing between the coiled tubing completion connector and the coiled tubing 10 can be better guaranteed, making the coiled tubing completion connector suitable for high-temperature, high-pressure, and corrosive oil and gas production environments, ensuring long-term reliable operation.

[0029] like Figure 1 and Figure 2 As shown, a first retaining ring 5 is provided between the connector body 6 and the metal sealing structure. The first retaining ring 5 can compress the metal sealing structure axially. A second retaining ring 7 is provided between the connector body 6 and the tapered slip 8. The second retaining ring 7 can compress the tapered slip 8 axially. By setting the first retaining ring 5, when tightening the connector body 6 and the upper connector 1, the wear on the metal sealing structure is reduced, so that the metal sealing structure is only subjected to the axial clamping force from the first retaining ring 5. Similarly, when tightening the lower cap 9 and the connector body 6, the wear on the tapered slip 8 is reduced, so that the tapered slip 8 is only subjected to the axial clamping force from the second retaining ring 7.

[0030] like Figure 1 , Figure 3 and Figure 8 As shown, the connector body 6 has at least two relatively parallel first clamping planes 6-1 on the side near the upper connector 1, and at least two relatively parallel second clamping planes 6-3 on the side near the lower pressure cap 9. Figure 1 , Figure 6 and Figure 8 As shown, the side of the lower pressure cap 9 is provided with at least two relatively parallel third clamping planes 9-1. In this embodiment, the first clamping plane 6-1, the second clamping plane 6-3, and the third clamping plane 9-1 are all four planes evenly distributed along the circumference of the connector body 6. By setting the first clamping plane 6-1, the second clamping plane 6-3, and the third clamping plane 9-1, it is convenient to use a wrench to perform the tightening operation between the connector body 6 and the upper connector 1, and between the lower pressure cap 9 and the connector body 6. The first clamping plane 6-1 is used to tighten the connector body 6 and the upper connector 1, and the second clamping plane 6-3 and the third clamping plane 9-1 are used to tighten the connector body 6 and the lower pressure cap 9.

[0031] Because the coiled tubing 10 is used as the production tubing string, the long-term tensile strength requirements for the coiled tubing completion connector are higher. However, existing coiled tubing completion connectors only have a tapered slip locking mechanism. This single-stage locking mechanism may experience stress concentration under high pressure and tubing weight, and during long-term operation, fluid vibration and other factors can easily lead to locking failure, failing to guarantee tensile strength and long-term sealing, and even posing a risk of the production tubing string falling off. Therefore, the coiled tubing completion connector provided by this invention also includes a second locking mechanism, such as... Figure 1 , Figure 4 and Figure 8 As shown, the second locking mechanism is a rivet-type locking mechanism, which is installed on the connector body 6. The connector body 6 has a threaded hole 6-2 for installing a threaded rivet, and a recess for the threaded rivet is pre-set on the continuous tubing 10. When installing to the last section of the continuous tubing 10, a pressing device is used to press the recess at the position corresponding to the threaded hole 6-2 on the upper part of the last section of the continuous tubing 10.

[0032] like Figure 1 , Figure 2 and Figure 4As shown, multiple sets of threaded hole groups are spaced apart along the axial direction of the connector body 6. Each threaded hole group includes multiple threaded holes 6-2 evenly distributed circumferentially along the connector body 6. Adjacent threaded hole groups are arranged at equal intervals with a 30° right-hand rotation angle, forming a spirally distributed threaded hole array. Specifically, in this embodiment, the multiple threaded holes 6-2 are arranged in four layers along the axial direction of the connector body 6, forming four threaded hole groups. Each layer has four threaded holes 6-2 evenly distributed circumferentially along the connector body 6, for a total of 16 threaded holes 6-2, achieving a high-strength connection. This arrangement enhances the locking strength and ensures the tensile strength of the coiled tubing completion connector during long-term use. Furthermore, adjacent threaded hole groups are arranged at equal intervals axially with a 30° right-hand rotation, forming a spirally distributed threaded hole array. This arrangement facilitates the installation of threaded rivets while ensuring that the coiled tubing 10 is subjected to a more evenly distributed locking force axially, enhancing the locking effect.

[0033] like Figure 5 and Figure 7 As shown, the conical slip 8 has several slip segments along its circumference, and slip teeth 8-1 are provided on the inner side of the slip segments. With this configuration, when the lower pressure cap 9 is tightened, the connector body 6 pushes the second retaining ring 7 and the conical slip 8, and under the action of the conical surface structure of the lower pressure cap 9, radially presses the slip segments, causing the slip teeth 8-1 to bite into the outer wall of the continuous tubing 10, achieving a tight connection. In this embodiment, as... Figure 5 As shown, the conical slip 8 has two slip segments.

[0034] When using the coiled tubing completion connector provided by this utility model, the coiled tubing 10 is inserted into the upper connector 1, connector body 6, tapered slip 8, and lower pressure cap 9, aligning the recess on the coiled tubing 10 with the threaded hole 6-2. After tightening all components and securing the coiled tubing 10 with threaded rivets, the coiled tubing completion connector is then connected to the... Figure 10 The installation work is completed below the wellhead hanger 11 shown.

[0035] This invention provides a coiled tubing completion connector with improved sealing and tensile strength through the design of a composite sealing and locking structure. The composite sealing structure, employing high-temperature and high-pressure resistant sealing rings 1-2 and a brass metal sealing ring 3, can withstand pressures up to 50 MPa. The composite locking structure, using rivets and slips, can withstand a tensile force of 300 kN, which is 1.5 to 2.0 times the tensile force required to pull the completion production tubing string. The performance of this device fully meets the production requirements of shale gas wells.

[0036] In summary, this utility model, by designing an upper connector 1 and a connector body 6 and setting a metal sealing structure between them, and by setting a sealing ring 1-2 inside the upper connector 1, designs a composite sealing structure that includes a metal sealing structure. This ensures the overall sealing performance of the coiled tubing completion connector and solves the problem of leakage caused by the easy aging and failure of the sealing ring in traditional sealing ring structures under high temperature, high pressure and corrosive environments. This makes the coiled tubing completion connector suitable for high temperature, high pressure and corrosive oil and gas production environments, ensuring long-term reliable operation.

[0037] Although the present invention has been described with reference to preferred embodiments, various modifications can be made thereto and components can be replaced with equivalents without departing from the scope of the invention. In particular, the technical features mentioned in the various embodiments can be combined in any manner, provided there is no structural conflict. The present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A coiled tubing completion connector, characterized in that, include: The upper connector is connected to the wellhead hanger at its upper end, and its inner side is equipped with a sealing structure. The connector body is connected to the lower end of the upper connector. A metal sealing structure is provided between the upper connector and the connector body. The metal sealing structure includes a pressure ring and a metal sealing ring. The pressure ring can compress the metal sealing ring to deform it. The first locking mechanism includes a lower pressure cap and a conical collet disposed inside the lower pressure cap. The inner side of the lower pressure cap is provided with a conical surface structure that mates with the conical collet. The lower pressure cap is connected to the connector body. The upper connector, the connector body, and the lower pressure cap all have a cylindrical hollow structure for inserting continuous tubing.

2. The coiled tubing completion connector according to claim 1, characterized in that, The contact surface between the pressure ring and the metal sealing ring is provided with an annular protrusion, and the contact surface between the metal sealing ring and the pressure ring is provided with an annular groove that mates with the annular protrusion.

3. The coiled tubing completion connector according to claim 2, characterized in that, The pressure ring includes an upper pressure ring and a lower pressure ring, which are respectively disposed on the upper and lower sides of the metal sealing ring. The metal sealing ring has an annular deformation groove in the middle of both the inner and outer sides.

4. The coiled tubing completion connector according to claim 1, characterized in that, The sealing structure includes at least two sealing ring grooves for placing sealing rings.

5. The coiled tubing completion connector according to claim 4, characterized in that, The sealing ring is made of fluororubber.

6. The coiled tubing completion connector according to claim 1, characterized in that, A first retaining ring is provided between the connector body and the metal sealing structure, and the first retaining ring can compress the metal sealing structure axially; a second retaining ring is provided between the connector body and the tapered slip, and the second retaining ring can compress the tapered slip axially.

7. The coiled tubing completion connector according to claim 1, characterized in that, The connector body has at least two relatively parallel first clamping planes on the side near the upper connector end, at least two relatively parallel second clamping planes on the side near the lower cap end, and at least two relatively parallel third clamping planes on the side of the lower cap.

8. The coiled tubing completion connector according to claim 1, characterized in that, It also includes a second locking mechanism, which is a rivet-type locking mechanism, and is disposed on the connector body. The connector body is provided with a threaded hole for installing a threaded rivet, and the continuous tubing is pre-set with a recess for cooperating with the threaded rivet.

9. The coiled tubing completion connector according to claim 8, characterized in that, Multiple sets of threaded holes are provided at intervals along the axial direction of the connector body. Each set of threaded holes includes multiple threaded holes evenly distributed along the circumference of the connector body. Adjacent sets of threaded holes are arranged at equal intervals with a 30° right-hand helical angle to form a spirally distributed array of threaded holes.

10. The coiled tubing completion connector according to any one of claims 1-9, characterized in that, The conical latch has several latch flaps along its circumference, and the inner side of each latch flap has latch teeth.

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