Circulating sliding sleeve

Abstract

The utility model relates to a circulating sliding sleeve which comprises an upper connector, a middle connector, a lower connector, an inner sliding sleeve and a ball seat. The upper joint and the lower joint are hermetically inserted into two ends of the middle joint respectively; the upper joint, the middle joint and the lower joint are provided with communicated inner cavities; the inner sliding sleeve is arranged in an inner cavity of the middle connector, and the inner sliding sleeve is provided with an inner channel. The ball seat is arranged in the middle of an inner channel of the inner sliding sleeve. A soluble ball is thrown into the inner sliding sleeve, after the soluble ball is supported on the ball seat, pressure building is carried out to drive the ball seat and the inner sliding sleeve to move in the inner cavity of the middle connector in the direction from the upper connector to the lower connector, and after the ball seat and the inner sliding sleeve move in place, well killing fluid channels located on the upper portion and the lower portion of the inner sliding sleeve are opened. The circulating sliding sleeve is opened by throwing the soluble ball for pressure building, well killing fluid channels on the upper portion and the lower portion of the circulating sliding sleeve are opened, well killing operation in the space above the circulating sliding sleeve can be carried out, and well killing operation in the space below the circulating sliding sleeve can also be carried out.

Description

Technical Field

[0001] The utility model relates to the technical field of oil and gas well completion operations, and particularly relates to a circulating sliding sleeve. Background Technique

[0002] During the oil well completion and well testing under high temperature and high pressure, after the completion string is lowered into the well, the Christmas tree is installed, the completion packer is set, and the production testing is completed, it is necessary to pull out the completion string above the anchoring mechanism part. An important key technical measure is the well killing operation. There are two common well killing methods. One well killing method is to punch holes in the tubing above the anchoring mechanism to connect the space inside the tubing with the annulus between the casing and the tubing to establish a circulating well killing channel. However, it is difficult to implement due to the influence of high temperature, high pressure and sulfur-containing conditions in the wellbore or the influence of large well deviation angle. At the same time, the operation risk is high and the operation cost is high. Another well killing method is to install a circulating sliding sleeve above the anchoring mechanism part and open the circulating sliding sleeve by ball plugging with resin balls to establish a circulating well killing channel. However, due to ball plugging, the lower channel of the circulating sliding sleeve is isolated, and the wellbore part below the circulating sliding sleeve cannot be well killed, which brings well control risks to the pulling out of the completion string. It can also use soluble balls to solve the problem of isolation of the lower channel of the circulating sliding sleeve, but the space where the soluble balls are located is very small and the liquid in the space cannot flow, and the dissolution of the soluble balls is uncontrollable, resulting in uncontrollable well killing operation time and high operation cost.

[0003] In current high temperature, high pressure and sulfur-containing wells, due to high pressure, high temperature, high sulfur content and strong corrosion, the requirements for the pressure-bearing operation equipment for tubing perforation are too high, the risk of tubing perforation operation is extremely high, and at the same time the operation cost is too high. Generally, tubing perforation is difficult to implement.

[0004] In highly deviated wells, due to the large well deviation, it brings certain risks to the lowering and positioning of the tubing perforation device, and it is difficult to successfully implement the tubing perforation operation.

[0005] Currently, all existing circulating sliding sleeves adopt the resin ball opening method. However, due to the ball plugging and pressure opening method, the upper and lower spaces of the circulating sliding sleeve are isolated. As a result, during the later well killing operation, the well killing operation can only be realized in the space above the circulating sliding sleeve, and the wellbore space below the circulating sliding sleeve cannot be well killed. This will lead to the incompleteness of the well killing operation of the entire wellbore. When pulling out the completion string, the wellbore liquid column pressure will be lower than the bottom hole pressure, which is extremely likely to cause well kick, overflow, and even serious accidents such as blowout.

[0006] Existing circulating sliding sleeves adopt the soluble ball opening method. However, after the soluble balls fall on the internal ball seat of the circulating sliding sleeve, the upper and lower spaces are small and the liquid does not have fluidity, which will lead to a significant reduction in the dissolution rate of the soluble balls. The dissolution time of the soluble balls is uncertain, the well killing operation time is uncontrollable, and the operation cost is high. Utility Model Content

[0007] The utility model aims to solve at least one technical problem in the background technology and provide a circulating sliding sleeve.

[0008] To achieve the above object, the utility model provides a circulating sleeve, comprising: an upper joint, an intermediate joint, a lower joint, an inner sleeve and a ball seat;

[0009] The upper joint and the lower joint are respectively sealed and plugged at two ends of the middle joint;

[0010] The upper joint, the middle joint and the lower joint have inner cavities;

[0011] The inner sleeve is arranged in the inner cavity of the middle joint, and the inner sleeve is provided with an internal channel;

[0012] The ball seat is arranged in the middle of the inner channel of the inner sleeve;

[0013] By throwing a soluble ball into the inner sleeve, the soluble ball is supported on the ball seat and then the pressure is held to drive the ball seat and the inner sleeve to move in the inner cavity of the middle joint along the direction from the upper joint to the lower joint. After moving into place, the well-killing fluid channels located at the upper and lower parts of the inner sleeve are opened.

[0014] According to one aspect of the utility model, the inner sleeve comprises a first sleeve portion and a second sleeve portion, the first sleeve portion and the second sleeve portion are fixedly connected, and the wall thickness of the first sleeve portion is greater than the wall thickness of the second sleeve portion;

[0015] The ball seat is arranged at the end of the second sleeve part close to the first sleeve part, and its outer wall is sealed with the inner wall of the second sleeve part. The end of the through hole arranged at the center for supporting the soluble ball has an air gap with the tail end of the first sleeve part.

[0016] According to one aspect of the utility model, a plurality of first through holes are evenly arranged circumferentially at one end of the middle joint close to the upper joint;

[0017] When the inner sleeve is driven by the soluble ball to move toward the lower joint, the first through hole is communicated with the inner cavity of the upper joint to form a well-killing fluid channel located on the upper part of the inner sleeve.

[0018] According to one aspect of the utility model, second through holes are evenly distributed circumferentially at one end of the inner sleeve away from the upper joint, and the second through holes are located on a side of the ball seat away from the soluble ball.

[0019] According to one aspect of the utility model, a plurality of third through holes are evenly arranged circumferentially at one end of the middle joint close to the lower joint;

[0020] When the inner sliding sleeve moves towards the lower sub through the driving of the soluble ball and abuts against the end of the lower sub, the second through hole communicates with the third through hole to form a kill fluid passage located at the lower part of the inner sliding sleeve.

[0021] According to one aspect of the present utility model, before the soluble ball is thrown, one end of the inner sliding sleeve abuts against one end of the upper sub, the outer wall of the inner sliding sleeve is connected to the intermediate sub through shear pins, and the outer wall of the inner sliding sleeve seals the first through hole.

[0022] According to one aspect of the present utility model, the upper sub and the intermediate sub are hermetically connected through an O-ring seal;

[0023] A plurality of groups of O-ring seals are arranged at intervals on the outer wall of the inner sliding sleeve and are slidably and hermetically connected to the inner wall of the intermediate sub;

[0024] The intermediate sub and the lower sub are hermetically connected through an O-ring seal.

[0025] According to the solution of the present utility model, the kill fluid circulating sliding sleeve of the present utility model is based on the original circulating sliding sleeve, and a mechanism for synchronously opening the passage is added at the lower part of the circulating sliding sleeve. While opening the kill fluid passage at the upper part of the circulating sliding sleeve (communicating the inner space of the tubing with the annulus between the casing and the tubing) by ball throwing and pressure buildup, the kill fluid passage at the lower part of the circulating sliding sleeve (communicating the inner space of the tubing with the annulus between the casing and the tubing) is also opened; after the circulating sliding sleeve is opened by pressure buildup, there is no isolated space in the entire wellbore. In this way, when performing the kill operation, the kill operation for the space above the circulating sliding sleeve and the kill operation for the space below the circulating sliding sleeve can be implemented.

[0026] According to the solution of the present utility model, the kill fluid circulating sliding sleeve of the present utility model only needs to be opened by ball throwing and pressure buildup, and is not affected by high temperature, high pressure and sulfur-containing conditions. Moreover, even in highly deviated wells or even horizontal wells, the circulating sliding sleeve can be opened by pumping the ball in place. The installation method is to install a circulating sliding sleeve of the present utility model above the packer anchoring mechanism. The cost only increases the tool cost of a circulating sliding sleeve of the present utility model, with low risk and controllable cost. After the circulating sliding sleeve is seated by ball throwing, a certain pump pressure is applied at the wellhead. The shear pins of the inner sliding sleeve inside the circulating sliding sleeve are sheared and the inner sliding sleeve descends, simultaneously opening the kill fluid passages at the upper and lower parts of the circulating sliding sleeve (communicating the inner space of the tubing with the annulus between the casing and the tubing), creating conditions for performing the kill operation for the entire wellbore, with simple operation, no risk and low cost.

[0027] According to the solution of the present utility model, there is no need to perforate the tubing. Only by pumping and holding pressure with a ball (either a resin ball or a soluble ball) can the circulation sliding sleeve be opened. Whether it is a high-temperature, high-pressure sour well, a highly deviated well or a well under other well conditions, the operation is the same. The operation is simple and risk-free, and the tool cost is low.

[0028] By pumping and holding pressure with a resin ball to open the circulation sliding sleeve, there is also an opening mechanism at the lower part of the inner sliding sleeve. When pumping and holding pressure with the ball to open the kill fluid passage at the upper part of the circulation sliding sleeve (connecting the inner space of the tubing with the annulus between the casing and the tubing), the opening mechanism simultaneously opens the kill fluid passage at the lower part of the circulation sliding sleeve (connecting the inner space of the tubing with the annulus between the casing and the tubing), solving the problem that the lower channel of the circulation sliding sleeve is isolated, and the kill operation of the entire wellbore can be realized.

[0029] By pumping and holding pressure with a soluble ball to open the circulation sliding sleeve, the kill fluid passages at the upper and lower parts of the circulation sliding sleeve (connecting the inner space of the tubing with the annulus between the casing and the tubing) are both opened. There is no need to wait for the soluble ball to dissolve, and the kill operation can be directly carried out. The kill operation time is controllable, and the operation cost is low. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 Schematically showing a structural cross-sectional view of the initial state of the circulation sliding sleeve according to an embodiment of the present utility model;

[0031] Figure 2 Schematically showing a structural cross-sectional view of the moving state of the inner sliding sleeve in the circulation sliding sleeve according to an embodiment of the present utility model;

[0032] Figure 3 Schematically showing a structural cross-sectional view of the inner sliding sleeve in the circulation sliding sleeve moving into place to open the kill fluid passage according to an embodiment of the present utility model. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0033] Now, the content of the present utility model will be described with reference to exemplary embodiments. It should be understood that the described embodiments are only for enabling those of ordinary skill in the art to better understand and thus implement the content of the present utility model, rather than implying any limitation on the scope of the present utility model.

[0034] As used herein, the term "comprising" and its variants are to be construed as open-ended terms meaning "including but not limited to". The term "based on" is to be construed as "at least partially based on". The terms "one embodiment" and "an embodiment" are to be construed as "at least one embodiment".

[0035] Figure 1 Schematically showing a structural cross-sectional view of the initial state of the circulation sliding sleeve according to an embodiment of the present utility model; Figure 2Schematic cross-sectional view showing the movement state structure of the inner sliding sleeve in a circulating sliding sleeve according to an embodiment of the present invention; Figure 3 Schematic cross-sectional view showing the structure of the inner sliding sleeve in the circulating sliding sleeve moving into place to open the kill fluid passage according to an embodiment of the present invention. As Figures 1 - 3 shown, in this embodiment, the circulating sliding sleeve includes: an upper joint 1, an intermediate joint 2, a lower joint 3, an inner sliding sleeve 4, and a ball seat 5;

[0036] The upper joint 1 and the lower joint 3 are respectively sealed and inserted at both ends of the intermediate joint 2;

[0037] The upper joint 1, the intermediate joint 2, and the lower joint 3 have an inner cavity 6;

[0038] The inner sliding sleeve 4 is arranged in the inner cavity 6 of the intermediate joint 2, and the inner sliding sleeve 4 is provided with an internal passage 7;

[0039] The ball seat 5 is arranged in the middle of the internal passage 7 of the inner sliding sleeve 4;

[0040] By throwing a soluble ball 8 into the inner sliding sleeve 4, after the soluble ball 8 is supported on the ball seat 5, pressure is applied to drive the ball seat 5 and the inner sliding sleeve 4 to move in the inner cavity 6 of the intermediate joint 2 along the direction from the upper joint 1 to the lower joint 3. After moving into place, the kill fluid passages located above and below the inner sliding sleeve 4 are opened.

[0041] As Figure 1 shown, when the soluble ball reaches the position and the inner sliding sleeve has not been activated yet, neither the kill fluid passage in the upper part of the circulating sliding sleeve nor the kill fluid passage in the lower part of the circulating sliding sleeve is opened;

[0042] As Figure 2 shown, after the soluble ball reaches the position, pressure is applied to drive the inner sliding sleeve to start. During operation, the kill fluid passage in the upper part of the circulating sliding sleeve and the kill fluid passage in the lower part of the circulating sliding sleeve cannot be connected;

[0043] As Figure 3 shown, when the inner sliding sleeve moves into place, both the kill fluid passage in the upper part of the circulating sliding sleeve and the kill fluid passage in the lower part of the circulating sliding sleeve are opened and can be connected. At this time, the positive circulating kill operation can be carried out. The kill fluid enters the kill fluid passage in the upper part of the circulating sliding sleeve, and the kill fluid also enters the kill fluid passage in the lower part of the circulating sliding sleeve, and the entire wellbore is filled with the kill fluid.

[0044] Furthermore, as Figures 1 - 3 shown, in this embodiment, the inner sliding sleeve 4 includes a first sliding sleeve part 14 and a second sliding sleeve part 15. The first sliding sleeve part 14 and the second sliding sleeve part 15 are fixedly connected, and the wall thickness of the first sliding sleeve part 14 is greater than the wall thickness of the second sliding sleeve part 15;

[0045] As Figures 1 - 3As shown in the figure, in this embodiment, the ball seat 5 is arranged at the end of the second sliding sleeve part 15 close to the first sliding sleeve part 14. Its outer wall is hermetically connected to the inner wall of the second sliding sleeve part 15. The end 16 of the through hole provided in its center for supporting the soluble ball has an air gap 17 with the tail end of the first sliding sleeve part 14. With such an arrangement, the soluble ball can be limited and supported during the process of falling into the inner sliding sleeve 4, so that the soluble ball can be stably supported on the ball seat 5 with a better sealing and pressure-holding effect. Moreover, the air gap 17 provided between the end of the ball seat 5 and the tail end of the first sliding sleeve part can play an adaptive buffering role when the soluble ball falls to the ball seat 5, ensuring that the soluble ball will not directly hit the end of the ball seat 5, resulting in damage to the ball seat, thereby effectively ensuring the normal working life of the ball seat 5. Such a solution effectively solves the problems of poor stability, poor sealing and pressure-holding effect, and easy damage to the ball seat caused by directly throwing the soluble ball to the top of the inner sliding sleeve in the traditional solution.

[0046] Furthermore, as Figures 1 - 3 shown, in this embodiment, a plurality of first through holes 9 are evenly arranged circumferentially at one end of the intermediate joint 2 close to the upper joint 1;

[0047] When the inner sliding sleeve 4 drives and moves towards the lower joint 3 through the soluble ball 8, the first through holes 9 communicate with the inner cavity of the upper joint 1 to form a kill fluid channel located above the inner sliding sleeve 4.

[0048] Furthermore, as Figures 1 - 3 shown, in this embodiment, a plurality of second through holes 10 are evenly arranged circumferentially at one end of the inner sliding sleeve 4 away from the upper joint 1, and the second through holes 10 are located on the side of the ball seat 5 facing away from the soluble ball 8.

[0049] Furthermore, as Figures 1 - 3 shown, in this embodiment, a plurality of third through holes 11 are evenly arranged circumferentially at one end of the intermediate joint 2 close to the lower joint 3;

[0050] When the inner sliding sleeve 4 drives and moves towards the lower joint 3 through the soluble ball 8 until it abuts against the end of the lower joint 3, the second through holes 10 communicate with the third through holes 11 to form a kill fluid channel located below the inner sliding sleeve 4.

[0051] Furthermore, as Figures 1 - 3 shown, in this embodiment, before the soluble ball 8 is thrown, one end of the inner sliding sleeve 4 abuts against one end of the upper joint 1. The outer wall of the inner sliding sleeve 4 is connected to the intermediate joint 2 through a shear pin 12, and the outer wall of the inner sliding sleeve 4 blocks the first through holes 9.

[0052] Furthermore, as Figures 1 - 3 shown, in this embodiment, the upper joint 1 and the intermediate joint 2 are hermetically connected through an O-ring 13;

[0053] Multiple groups of O-ring seals 13 are arranged at intervals on the outer wall of the inner sliding sleeve 4 and are slidably and sealingly connected to the inner wall of the intermediate joint 2;

[0054] The intermediate joint 2 and the lower joint 3 are sealingly connected through an O-ring seal 13.

[0055] According to the above solution of the present invention, the structure of the present invention is designed as three separate parts: the ball seat 5, the first sliding sleeve part 14, and the second sliding sleeve part 15, which can reduce the processing cost of materials and improve the precision requirements of the ball seat, including requirements for dimensional accuracy, shape accuracy, position accuracy, etc.; it is also convenient for manufacturing process treatment. For example, processes such as surface spraying do not require particularly long related containers. The most important thing is that the product can be serialized. For example, the inner sliding sleeve, that is, the first sliding sleeve part 14 and the second sliding sleeve part 15, are only processed into one standard specification. When customers have different requirements for the ball throwing size, only the ball seat 5 needs to be redesigned to meet different requirements, saving design costs and labor costs, accelerating the production progress, and shortening the delivery cycle.

[0056] According to the above solution of the present invention, the circulating sliding sleeve for well killing of the present invention is based on the original circulating sliding sleeve, and a set of mechanisms for synchronously opening the channel is added at the lower part of the circulating sliding sleeve. While opening the well-killing fluid channel (connecting the inner space of the tubing with the annulus between the casing and the tubing) at the upper part of the circulating sliding sleeve by throwing a ball and building up pressure, the well-killing fluid channel (connecting the inner space of the tubing with the annulus between the casing and the tubing) at the lower part of the circulating sliding sleeve is also opened; after the circulating sliding sleeve is opened by building up pressure, there is no isolated space in the entire wellbore. In this way, when implementing the well-killing operation, the well-killing operation for the space above the circulating sliding sleeve can be carried out, and the well-killing operation for the space below the circulating sliding sleeve can also be carried out.

[0057] According to the above solution of the present invention, the circulating sliding sleeve for well killing of the present invention only needs to be opened by throwing a ball and building up pressure, and is not affected by high-temperature, high-pressure, and sulfur-containing conditions. Moreover, even in highly deviated wells or even horizontal wells, the circulating sliding sleeve can be opened by pumping the ball in place. The installation method is to install a circulating sliding sleeve of the present invention above the packer anchoring mechanism, and the cost only increases the tool cost of a circulating sliding sleeve of the present invention, with low risk and controllable cost. After the circulating sliding sleeve is seated by throwing a ball, a certain pump pressure is applied at the wellhead, and the inner sliding sleeve in the circulating sliding sleeve shears the shear pins and descends, simultaneously opening the well-killing fluid channels (connecting the inner space of the tubing with the annulus between the casing and the tubing) at the upper and lower parts of the circulating sliding sleeve, creating conditions for implementing the well-killing operation for the entire wellbore, with simple operation, no risk, and low cost.

[0058] According to the above solution of the present invention, there is no need to perforate the tubing. Only by throwing a ball (either a resin ball or a soluble ball) and pumping to build up pressure can the circulating sliding sleeve be opened. Whether it is a high-temperature, high-pressure, sulfur-containing well, a highly deviated well, or a well under other well conditions, the operation is the same, with simple operation, no risk, and low tool cost.

[0059] The circulating sliding sleeve is opened by injecting resin balls to build up pressure. Meanwhile, there is also an opening mechanism at the lower part of the inner sliding sleeve. When the resin balls are injected to build up pressure to open the kill fluid passage at the upper part of the circulating sliding sleeve (connecting the inner space of the tubing with the annulus between the casing and the tubing), the opening mechanism simultaneously opens the kill fluid passage at the lower part of the circulating sliding sleeve (connecting the inner space of the tubing with the annulus between the casing and the tubing), solving the problem of isolation of the lower channel of the circulating sliding sleeve, and the kill operation of the entire wellbore can be realized.

[0060] The circulating sliding sleeve is opened by injecting soluble balls to build up pressure. The kill fluid passages (connecting the inner space of the tubing with the annulus between the casing and the tubing) at the upper and lower parts of the circulating sliding sleeve are both opened. There is no need to wait for the soluble balls to dissolve, and the kill operation can be directly carried out. The time of the kill operation is controllable and the operation cost is low.

[0061] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention rather than to limit them. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made in form and details without departing from the scope defined by the claims of the present invention.

Claims

1. Circulating sliding sleeve, characterized in that, include: Upper joint, middle joint, lower joint, inner sleeve and ball seat; The upper joint and the lower joint are respectively sealed and plugged at two ends of the middle joint; The upper joint, the middle joint and the lower joint have inner cavities; The inner sleeve is arranged in the inner cavity of the middle joint, and the inner sleeve is provided with an internal channel; The ball seat is arranged in the middle of the inner channel of the inner sleeve; By throwing a soluble ball into the inner sleeve, the soluble ball is supported on the ball seat and then the pressure is held to drive the ball seat and the inner sleeve to move in the inner cavity of the middle joint along the direction from the upper joint to the lower joint. After moving into place, the well-killing fluid channels located at the upper and lower parts of the inner sleeve are opened.

2. The circulating sliding sleeve according to claim 1, wherein, The inner sliding sleeve comprises a first sliding sleeve portion and a second sliding sleeve portion, the first sliding sleeve portion and the second sliding sleeve portion are fixedly connected, and the wall thickness of the first sliding sleeve portion is greater than the wall thickness of the second sliding sleeve portion; The ball seat is arranged at the end of the second sleeve part close to the first sleeve part, and its outer wall is sealed with the inner wall of the second sleeve part. The end of the through hole arranged at the center for supporting the soluble ball has an air gap with the tail end of the first sleeve part.

3. The circulating sliding sleeve according to claim 1, wherein A plurality of first through holes are evenly distributed circumferentially on one end of the middle joint close to the upper joint; When the inner sleeve is driven by the soluble ball to move toward the lower joint, the first through hole is communicated with the inner cavity of the upper joint to form a well-killing fluid channel located on the upper part of the inner sleeve.

4. The circulating sliding sleeve according to claim 1, wherein The inner sleeve has one end away from the upper joint and is evenly provided with second through holes in the circumferential direction. The second through holes are located on a side of the ball seat away from the soluble ball.

5. The circulating sliding sleeve according to claim 4, wherein A plurality of third through holes are evenly arranged circumferentially on one end of the middle joint close to the lower joint; When the inner sleeve is driven by the soluble ball to move toward the lower joint until it abuts against the end of the lower joint, the second through hole is communicated with the third through hole to form a well killing fluid channel located below the inner sleeve.

6. The circulating sliding sleeve according to claim 3, characterized in that, Before throwing the soluble ball, one end of the inner sleeve abuts against one end of the upper joint, the outer wall of the inner sleeve is connected to the middle joint through a shear pin, and the outer wall of the inner sleeve blocks the first through hole.

7. The circulating sliding sleeve according to any one of claims 1-6, characterized in that, The upper joint and the middle joint are sealed and connected via an O-ring; A plurality of groups of O-rings are arranged at intervals on the outer wall of the inner sleeve and are slidably and sealingly connected to the inner wall of the middle joint; The middle joint and the lower joint are sealed and connected via an O-ring.

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