Tubular column uncoupling compensator

Abstract

The utility model belongs to the technical field of downhole tools, and particularly relates to a tubular column uncoupling compensator. The tubular column uncoupling compensator comprises an inner cylinder connected with the upper connector and an outer cylinder connected with the lower connector, the outer cylinder is arranged on the outer wall of the inner cylinder in a sliding and sleeving mode, a limiting structure used for limiting the axial movement stroke of the inner cylinder and the outer cylinder is arranged between the inner cylinder and the outer cylinder, and the inner cylinder is provided with a locking mechanism used for keeping the limiting structure in the limiting state. When the tubular column is influenced by factors such as temperature and pressure, the inner cylinder and the outer cylinder move relatively in the axial direction within the range limited by the limiting structure so as to provide telescopic compensation for the tubular column, compared with the prior art, the tubular column disconnecting compensator can be in a working state without pitching and pressing operation, and the operation procedure is simplified; in the downhole operation process, the limiting structure keeps limiting the axial movement stroke of the inner cylinder and the outer cylinder under the cooperation of the locking mechanism, so that the inner cylinder directly bears the weight, transmitted by the outer cylinder, of downhole operation tools such as pipe columns, and safety of production operation is guaranteed.

Description

Technical Field

[0001] The utility model belongs to the technical field of downhole tools, and specifically relates to a pipe column disconnection compensator. Background Technology

[0002] The packer is a commonly used downhole tool with elastic sealing elements. It can isolate various sizes of tubing and wellbore and the annular space between tubing to form an operating layer to control the production of fluid and protect the casing. Usually, the packer is fixed on the tubing. In the layered steam injection and layered water blocking operations, two or more stages of packers are often used in combination to achieve the purpose of layered oil and gas production, or to isolate oil, gas and water layers. However, in production practice, due to the influence of production operations, the formation mud and sand are returned into the inlet tube with the well fluid and deposited on the upper part of each stage of the packer. At the same time, combined with the unsealing force of each stage of the packer itself, if the multi-stage packer is unsealed at the same time, the unsealing load will be large; if the tubing is stuck due to sand production, scaling, etc., the unsealing load will be even greater, which is easy to cause unsealing failure. At the same time, the downhole tubing is affected by the combined influence of downhole pressure, temperature and other factors, and will inevitably experience expansion and creep during operation. Especially during the steam or water injection process of thermal recovery operations, the expansion and creep of the production tubing connected between adjacent packers will inevitably bring additional axial force to the packer, affecting its working performance; for the tubing itself, the tubing between the packers will inevitably be subject to the axial stress generated by the expansion and creep, causing the tubing to bend, deform or break.

[0003] The Chinese utility model patent with the authorization announcement number CN207110986U and the authorization announcement date March 16, 2018 discloses a telescopic tube for downhole tubulars, including an inner telescopic compensation tube (i.e., inner tube), a tubular ball seat (i.e., sliding sleeve), and an outer telescopic compensation tube (i.e., outer sleeve). The inner end of the inner telescopic compensation tube is connected to the tubular ball seat through a destructible connection structure (i.e., locking pin), and the end of the tubular ball seat away from the inner telescopic compensation tube is provided with a first limiting structure for limiting the telescopic amount. The inner end of the outer telescopic compensation tube is connected to the tubular ball seat through the first limiting structure, and the other end is connected to the inner telescopic compensation tube sleeve. A surplus amount for axial telescopic expansion is left between the outer telescopic compensation tube and the inner telescopic compensation tube.

[0004] However, when the telescopic tube for the downhole tubular column is used, it is necessary to first throw a steel ball into the tubular column and pressurize it to shear off the connection between the tubular ball seat and the inner telescopic compensation tube so that the telescopic tube is in a telescopic working state; when the telescopic tube is lowered into the well, since the inner telescopic compensation tube is connected to the tubular ball seat through a shear pin, the shear pin needs to bear the weight of the downhole working tools such as the tubular column connected to the telescopic tube. Under the combined effect of the weight of the downhole working tools such as the tubular column and the pressure in the well, there is a risk that the shear pin will be sheared off in advance, thereby causing a production accident. Contents of utility model

[0005] The purpose of the present utility model is to provide a pipe string disconnection compensator, so as to solve the problems of cumbersome operation procedures caused by the need to first throw a ball and apply pressure in the prior art when using a telescopic pipe for downhole pipe strings to make the telescopic pipe in a telescopic working state, and the problem that when the telescopic pipe is lowered into the well, the shear pin needs to bear the weight of downhole operation tools such as the pipe string connected to the telescopic pipe and is cut off in advance.

[0006] To achieve the above purpose, the following technical solutions are adopted for the pipe string disconnection compensator in the present utility model:

[0007] A pipe string disconnection compensator includes an inner cylinder connected to an upper joint and an outer cylinder connected to a lower joint. The outer cylinder is slidably sleeved on the outer wall of the inner cylinder. A limiting structure for defining the axial movement stroke of the two is provided between the inner cylinder and the outer cylinder, and the inner cylinder is configured with a locking mechanism for keeping the limiting structure in a limiting state.

[0008] Further, the limiting structure includes a claw provided at the lower part of the inner cylinder. The claw has a first stop portion for restricting the upward stroke of the inner cylinder, and the outer cylinder is provided with a second stop portion that is in stop cooperation with the first stop portion.

[0009] Further, the mating surfaces of the first stop portion and the second stop portion are guiding inclined surfaces.

[0010] Further, the number of claws is at least two, and each claw is arranged at the lower end of the inner cylinder at equal intervals in the circumferential direction.

[0011] Further, the locking mechanism includes a sliding sleeve, and the sliding sleeve is connected to the inner cylinder through a disconnectable connection structure.

[0012] Further, the disconnectable connection structure is a locking pin.

[0013] Further, a ball seat sealing surface is provided at the upper end of the sliding sleeve.

[0014] Further, a sealing structure is provided between the inner cylinder and the outer cylinder. The sealing structure includes a graphite ring and / or a sealing ring provided between the inner cylinder and the outer cylinder.

[0015] Further, a limiting pressure ring is threadedly connected to the outer cylinder for restricting the graphite ring.

[0016] Further, the limiting pressure ring is provided with a guiding structure.

[0017] The beneficial effects of the present utility model are as follows: The present utility model is improved based on the prior art. By providing a limiting structure between the inner cylinder and the outer cylinder for restricting their axial movement, when the pipe string is affected by factors such as temperature and pressure, the inner cylinder and the outer cylinder can relatively axially move within the range restricted by the limiting structure, thereby providing telescopic compensation for the pipe string. Compared with the prior art, it is not necessary to perform operations such as ball throwing and pressure pumping to enable the inner cylinder and the outer cylinder to be in a telescopic working state, simplifying the operation procedure. At the same time, during the downhole operation process, the limiting structure, in cooperation with the locking mechanism, maintains the limitation of the axial movement stroke of the inner cylinder and the outer cylinder, enabling the inner cylinder to directly bear the weight of downhole operation tools such as the pipe string transmitted by the outer cylinder. Compared with the prior art, it ensures the safety of production operations. Description of the Drawings

[0018] Figure 1 It is a schematic structural diagram of the pipe string disconnection compensator in the embodiment of the pipe string disconnection compensator of the present utility model.

[0019] In the figure: 1, upper joint; 2, inner pipe; 3, limiting retaining ring; 4, sliding sleeve; 5, outer sleeve; 6, lower joint; 21, second sealing ring; 22, claw arm; 23, first limiting shoulder; 24, locking pin; 41, first sealing ring; 42, ball seat sealing surface; 51, first graphite ring; 52, second limiting shoulder; 53, diameter-expanded section; 61, third sealing ring; 62, second graphite ring. Detailed Embodiments

[0020] The features and performance of the present utility model will be further described in detail below in conjunction with the embodiments.

[0021] The present utility model provides a pipe string disconnection compensator. By providing a limiting structure between the inner cylinder and the outer cylinder for restricting their axial movement, the inner cylinder and the outer cylinder have the ability of telescopic compensation. At the same time, through the cooperation of the limiting structure and the locking mechanism, the inner cylinder directly bears the weight of downhole operation tools such as the pipe string. Compared with the prior art, it simplifies the operation procedure and ensures the safety of production operations.

[0022] Embodiment of the pipe string disconnection compensator in the present utility model:

[0023] As Figure 1 shown, this embodiment provides a pipe string disconnection compensator, including an inner cylinder and an outer cylinder movably sleeved at one end of the inner cylinder.

[0024] In this embodiment, the inner cylinder includes an upper joint 1 and an inner pipe 2 threadedly connected to the upper joint 1; the outer cylinder includes a lower joint 6 and an outer sleeve 5 threadedly connected to the lower joint 6. Among them, the upper joint 1 has an internal thread, one end of the upper joint 1 is connected to the well inner string, and the other end is threadedly connected to the inner pipe 2; the lower end of the outer sleeve 5 is connected to one end of the lower joint 6 through an internal thread, and the other end of the lower joint 6 is connected to the well inner string through an external thread; the outer periphery of the end of the inner pipe 2 away from the upper joint 1 is sealingly sleeved with the outer sleeve 5 in an axially movable manner, and a compensation distance for axial expansion and contraction is formed between the lower end surface of the inner pipe 2 and the upper end surface of the lower joint 6. Of course, in other embodiments, the upper joint 1 and the inner pipe 2 can be fixedly connected by welding or the like. Similarly, the lower joint 6 and the outer sleeve 5 can be fixedly connected by welding or the like.

[0025] In this embodiment, an inner conical surface structure is provided at one end of the lower joint 6 close to the upper joint 1, so as to provide a guiding function for the fishing anchor when it is lowered.

[0026] A limiting structure for limiting the axial movement stroke of the inner pipe 2 and the outer sleeve 5 is provided between the inner pipe 2 and the outer sleeve 5. In this embodiment, the limiting structure includes a first stop portion provided outside the lower end of the inner pipe 2 and a second stop portion provided on the outer sleeve 5 and used for stop cooperation with the first stop portion to limit the axial expansion and contraction compensation distance; the first stop portion and the second stop portion constitute the first limiting structure.

[0027] Specifically, the inner pipe 2 includes a claw provided at the lower end of the inner pipe 2. The claw includes a claw arm 22 connected to the body of the inner pipe 2 and a first limiting shoulder 23 provided at the end of the claw arm 22; the outer sleeve 5 includes an expanded diameter section 53 and a second limiting shoulder 52 for cooperation with the first limiting shoulder 23. Among them, the second limiting shoulder 52 protrudes inward along the radial direction of the expanded diameter section 53, and the expanded diameter section 53 is used for the first limiting shoulder 23 of the inner pipe 2 to slide axially for a certain distance; the limit of the extreme position when the inner pipe 2 and the outer sleeve 5 move away from each other is realized through the stop cooperation between the first limiting shoulder 23 and the second limiting shoulder 52. In this embodiment, the first limiting shoulder 23 constitutes the first stop portion for restricting the upward stroke of the inner pipe 2, and the second limiting shoulder 52 constitutes the second stop portion. During the downhole operation process, through the stop cooperation between the first limiting shoulder 23 and the second limiting shoulder 52, the inner pipe 2 directly bears the weight of downhole operation tools such as the pipe string transmitted by the outer sleeve 5, ensuring the safety of the production operation.

[0028] In order to improve the smoothness when the inner tube 2 is disengaged from the outer sleeve 5, the mating surfaces of the first stop portion and the second stop portion are guiding inclined surfaces. Specifically, one ends of the first limiting shoulder 23 and the second limiting shoulder 52 that are mated are both guiding inclined surfaces. Of course, in other embodiments, one end of the first limiting shoulder 23 and the second limiting shoulder 52 that are mated is a guiding inclined surface, and one end of the second limiting shoulder 52 and the first limiting shoulder 23 that are mated is a horizontal surface or an arc surface; or, one end of the second limiting shoulder 52 and the first limiting shoulder 23 that are mated is a guiding inclined surface, and one end of the first limiting shoulder 23 and the second limiting shoulder 52 that are mated is a horizontal surface or an arc surface. It should be understood that in this embodiment, by providing the guiding inclined surface, the claws of the inner tube 2 can be more easily contracted relative to the second limiting shoulder 52 of the outer sleeve 5 under the action of force, so that the outer sleeve 5 and the inner tube 2 are more smoothly disengaged from each other, and at the same time, the contact area is effectively increased during the stop cooperation to improve the effect of the limiting stop.

[0029] In order to ensure the effect when the first limiting shoulder 23 and the second limiting shoulder 52 are in stop cooperation, in this embodiment, the number of claws is set to four, and each claw is arranged at the lower end of the inner tube 2 at equal intervals in the circumferential direction. Of course, in other embodiments, the number of claws can be set to one, two or other appropriate numbers. It should be understood that the specific number of claws is preferably such that the connection strength between the inner tube 2 and the outer sleeve 5 can be ensured when the claws are in stop cooperation through the first limiting shoulder 23 and the second limiting shoulder 52. By setting an appropriate number of claws, the connection strength between the inner tube 2 and the outer sleeve 5 when the first limiting shoulder 23 and the second limiting shoulder 52 are in stop cooperation is ensured.

[0030] The inner tube 2 is configured with a locking mechanism for supporting and limiting the claws, so that the first limiting structure is maintained in a limiting state. Specifically, the inner tube 2 is connected with a sliding sleeve 4 for restricting the shrinkage and deformation of the claws through a disconnectable connection structure, and one end of the sliding sleeve 4 is connected to the inner wall of the first limiting shoulder 23 through a disconnectable connection structure. In this embodiment, the sliding sleeve 4 and the disconnectable connection structure constitute a locking mechanism.

[0031] During use, the sliding sleeve 4 supports and limits the claws of the inner tube 2 to restrict the shrinkage and deformation of the claws, so that the claws of the inner tube 2 are maintained in a stop state. Furthermore, the first limiting shoulder 23 of the claw is in stop cooperation with the second limiting shoulder 52 of the outer sleeve 5, so as to ensure that the first limiting shoulder 23 of the inner tube 2 and the outer sleeve 5 will not come out when moving relative to each other within the range of the axial telescopic compensation distance; when subjected to an external force, the disconnectable connection structure is damaged to release the connection between the sliding sleeve 4 and the inner tube 2, and further release the support restriction of the sliding sleeve 4 on the shrinkage and deformation of the claws. The claws are stressed and shrink and deform to release the stop cooperation between the first limiting shoulder 23 and the second limiting shoulder 52, so that the inner tube 2 is separated from the outer sleeve 5; at the same time, when the first limiting shoulder 23 and the second limiting shoulder 52 are in stop cooperation, the weight of downhole operation tools such as the pipe string connected to the lower joint 6 is directly transmitted to the inner tube 2 through the first limiting structure. In this process, the disconnectable connection structure does not bear the weight of downhole operation tools such as the pipe string.

[0032] In order to facilitate the positioning of the sliding sleeve 4 and the inner tube 2 when connected by the locking pin 24 during use, in this embodiment, the lower end surface of the sliding sleeve 4 is flush with the lower end surface of the inner tube 2.

[0033] In order to facilitate the sealing cooperation between the sliding sleeve 4 and the input steel ball when releasing the support limit of the sliding sleeve 4 on the claws, in this embodiment, the upper end of the sliding sleeve 4 is provided with a ball seat sealing surface 42. Specifically, the ball seat sealing surface 42 is set as a conical surface, so as to increase the force-bearing area of the sliding sleeve 4 and improve the shearing effect on the locking pin 24 to ensure the smooth disconnection between the sliding sleeve 4 and the inner tube 2. Of course, the ball seat sealing surface 42 can be set as a concave surface or other structural forms, which is specifically selected reasonably according to needs, and this embodiment does not limit this.

[0034] In this embodiment, the disconnectable connection structure is the locking pin 24. Through the connection method of the locking pin 24, the connection structure is simple; at the same time, the locking pin 24 is sheared after being subjected to a set external force, so that the sliding sleeve 4 and the inner tube 2 are smoothly separated, and further the support limit of the sliding sleeve 4 on the claws of the inner tube 2 is released.

[0035] The upper end of the outer sleeve 5 is also threadedly connected with a limit retaining ring 3, and the limit retaining ring 3 is in clearance fit with the inner tube 2. The limit retaining ring 3 is used to limit the first graphite ring 51 between the outer sleeve 5 and the inner tube 2. In this embodiment, the limit retaining ring 3 is provided with a guiding conical surface; specifically, the guiding conical surface is an inner conical surface structure provided at one end of the limit retaining ring 3 close to the upper joint 1, so as to facilitate guiding when fishing for the lower joint 6 and provide a guiding function for lowering the fishing anchor through this guiding conical surface.

[0036] In this embodiment, the limiting structure further includes a second limiting structure formed by the upper end face of the lower joint 6 and the lower end face of the inner tube 2. When the inner tube 2 slides relative to the outer sleeve 5 in the direction close to the lower joint 6, the upper end face of the lower joint 6 and the lower end face of the inner tube 2 are in a stop fit, thereby limiting the extreme position when the inner tube 2 moves towards the lower joint 6.

[0037] As a further embodiment, the limiting structure further includes a third limiting structure formed by the lower end face of the upper joint 1 and the upper end face or inner conical surface of the limiting pressure ring 3. When the inner tube 2 moves relative to the outer sleeve 5 in the direction close to the lower joint 6, the limiting pressure ring 3 and the lower end face of the upper joint 1 also form a stop fit, further limiting the extreme position when the inner tube 2 moves in the direction close to the lower joint 6; or, when the inner tube 2 moves in the direction away from the lower joint 6, the lower end face of the upper joint 1 and the upper end face or inner conical surface of the limiting pressure ring 3 form a stop fit to limit the extreme position when the inner tube 2 moves in the direction away from the lower joint 6.

[0038] A first sealing structure is provided between the inner tube 2 and the sliding sleeve 4. Specifically, a first sealing groove is provided on the sliding sleeve 4, and a first sealing ring 41 is provided in the first sealing groove. In this embodiment, two first sealing grooves are arranged at intervals along the axial direction of the sliding sleeve 4. Correspondingly, two first sealing rings 41 are also provided. The sliding sleeve 4 and the inner tube 2 are sealed through the first sealing structure, thereby preventing the influence of well impurities between the sliding sleeve 4 and the inner tube 2, ensuring that the sliding sleeve 4 can be smoothly disconnected from the inner tube 2 after the locking pin 24 is cut, and at the same time avoiding the problem that the claw cannot contract due to the influence of well impurities.

[0039] In order to ensure the sealing performance between the outer sleeve 5 and the inner tube 2 during relative sliding, in this embodiment, a second sealing structure is provided between the outer sleeve 5 and the inner tube 2. Specifically, a second sealing structure is provided between the upper end of the outer sleeve 5 and the inner tube 2. The second sealing structure includes a first graphite ring 51 provided between the outer sleeve 5 and the inner tube 2, a second sealing groove provided on the inner tube 2, and a second sealing ring 21 provided in the second sealing groove; wherein, two second sealing grooves are arranged at intervals along the axial direction of the inner tube 2. Correspondingly, two second sealing rings 21 are also provided. Of course, as other embodiments, only one of the first graphite ring or the second sealing ring is provided between the outer sleeve and the inner tube.

[0040] In order to ensure the sealing performance at the connection between the outer sleeve 5 and the lower joint 6, in this embodiment, a third sealing structure is provided between the outer sleeve 5 and the lower joint 6. Specifically, a second graphite ring 62 is arranged between the lower end face of the outer sleeve 5 and the lower joint 6, a third sealing groove is provided on the lower joint 6, and a third sealing ring 61 is arranged in the third sealing groove. Among them, two third sealing grooves are arranged at intervals along the axial direction of the lower joint 6. Correspondingly, two third sealing rings 61 are also provided. Of course, as other embodiments, only one of the second graphite ring or the third sealing ring is arranged between the outer sleeve and the lower joint.

[0041] When the pipe string disconnecting compensator of the present utility model is in use, the pipe string disconnecting compensator is connected between two-stage slip-type packers. It is threadedly connected to the upper packer through the upper joint 1 and threadedly connected to the lower packer through the lower joint 6. Then, the pipe string disconnecting compensator and the pipe string are lowered into the well together.

[0042] After the packer is set, when the pipe string is affected by factors such as temperature and pressure, the inner pipe 2 and the outer sleeve 5 expand and contract relative to each other, so as to realize the expansion and contraction compensation of the pipe string between adjacent packers. When the packer is released, if the release load exceeds the predetermined range, steel balls are put into the pipe string and fall onto the conical surface of the sliding sleeve 4 to be in sealing cooperation with the conical surface of the sliding sleeve 4. Pressure is applied to the pipe string until the locking pin 24 is cut off. After the locking pin 24 is cut off, the sliding sleeve 4 is disconnected from the inner pipe 2 and falls to the bottom of the well. At the same time, the support and limit of the sliding sleeve 4 on the claws of the inner pipe 2 are also released, so that the inner pipe 2 and the outer sleeve 5 are in a disconnected state. The upper packer is retrieved, and the upper joint 1 and the inner pipe 2 are retrieved with the upper packer. Then, a fishing anchor is put in to cooperate with the lower joint 6 to retrieve the lower packer, so as to realize the step-by-step release of multiple packers.

[0043] The above is only the preferred embodiment of the present utility model, and it is not intended to limit the present utility model. The patent protection scope of the present utility model is subject to the claims. All equivalent structural changes made by using the description and drawings of the present utility model should be included in the protection scope of the present utility model by the same token.

Claims

1. A pipe column disconnection compensator, comprising an inner tube connected to an upper joint and an outer tube connected to a lower joint, wherein the outer tube is slidably sleeved on the outer wall of the inner tube, characterized in that: A limiting structure for limiting the axial movement stroke of the inner cylinder and the outer cylinder is provided between the inner cylinder and the outer cylinder, the inner cylinder is provided with a locking mechanism for keeping the limiting structure in a limited state, the limiting structure comprises a claw provided at the lower part of the inner cylinder, the claw has a first stop portion for limiting the upper stroke of the inner cylinder, and the outer cylinder is provided with a second stop portion that cooperates with the first stop portion for stopping.

2. The pipe column disconnection compensator according to claim 1, characterized in that: The matching surfaces of the first stopper and the second stopper are guiding inclined surfaces.

3. The pipe column disconnection compensator according to claim 1, characterized in that: There are at least two claws, and the claws are evenly arranged at the lower end of the inner cylinder along the circumferential direction.

4. The pipe column disconnection compensator according to any one of claims 1 to 3, characterized in that: The locking mechanism comprises a sliding sleeve, and the sliding sleeve is connected to the inner cylinder via a disconnectable connection structure.

5. The pipe column disconnection compensator according to claim 4, characterized in that: The disconnectable connection structure is a locking pin.

6. The pipe column disconnection compensator according to claim 4, characterized in that: A ball seat sealing surface is provided at the upper end of the sliding sleeve.

7. The pipe column disconnection compensator according to any one of claims 1 to 3, characterized in that: A sealing structure is provided between the inner cylinder and the outer cylinder, and the sealing structure comprises a graphite ring and / or a sealing ring provided between the inner cylinder and the outer cylinder.

8. The pipe column disconnection compensator according to claim 7, characterized in that: The outer cylinder is threadedly connected with a limiting pressure ring for limiting the graphite ring.

9. The pipe column disconnection compensator according to claim 8, characterized in that: The limiting pressure ring is provided with a guiding structure.

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