Packer removal device and removal method

Abstract

This invention provides a packer removal device, comprising an insertion mechanism including a tubing string, a first short section extending radially outward from the tubing string, and a packer disposed downstream of the first short section for setting within the wellbore. A removal mechanism for insertion into the tubing string includes a drill pipe, a centralizer sleeved on the drill pipe for engaging with the first short section, and a cutter disposed at the lower end face of the drill pipe. This invention ensures smooth insertion of the tubing string into the wellbore and the drill pipe into the tubing string, and also ensures the cutter moves smoothly to a predetermined position, thereby improving the positioning accuracy and cutting quality of the cutter in the packer removal device.

Description

Technical Field

[0001] This invention relates to the field of well completion packers, and more particularly to a packer removal device and a removal method. Background Technology

[0002] Currently, the production string is difficult to remove during the later stages of unsealing or side-drilling in the wellbore. As a result, the use of removable permanent packers in wells such as gas storage facilities is gradually increasing.

[0003] In existing technologies, removable permanent packers are typically equipped with specialized removal tools for positioning and cutting the permanent packer. However, permanent packers can remain in use downhole for several years or even more than a decade. Providing specialized removal tools during these applications is difficult, and using cable-cutting tools is impractical in this type of well due to the non-magnetic nature of nickel-based alloy materials.

[0004] Therefore, it is desirable in the art to provide a packer removal device and removal method to solve the above-mentioned technical problems. Summary of the Invention

[0005] The purpose of this invention is to provide a packer removal device that can axially align and effectively engage with the first short section of the tubing during the tubing insertion process using a drill rod stabilizer, thereby ensuring that the cutter can move smoothly and accurately to the predetermined position, thus achieving the purpose of precise cutting.

[0006] According to a first aspect of the invention, a packer removal device is provided, comprising a lowering mechanism including a tubing string, a first short section extending radially outward from the tubing string, and a packer disposed downstream of the first short section for setting within the wellbore.

[0007] A removal mechanism for inserting into the tubing string, the removal mechanism including a drill pipe, a stabilizer sleeved on the drill pipe for engaging with the first short section, and a cutter disposed on the lower end face of the drill pipe.

[0008] In one embodiment, a pressure regulating chamber is formed within the drill pipe, and both the stabilizer and the cutter are configured to open under the pressure of the pressure regulating chamber.

[0009] In one embodiment, the centralizer is configured as a hydraulic centralizer, and the opening pressure of the centralizer is less than the opening pressure of the cutter.

[0010] In one embodiment, the distance between the stabilizer and the cutter is equal to the distance between the first short section and the packer.

[0011] In one embodiment, a radially inwardly extending safety valve is also provided on the tubing, the safety valve being located upstream of the first short section.

[0012] In one embodiment, the outer diameters of both the stabilizer and the cutter are smaller than the inner diameter of the safety valve in the contracted state.

[0013] In one embodiment, the tubing is further provided with a second short section extending radially inward for abutting against the cutter, the second short section being located downstream of the packer.

[0014] In one embodiment, the distance between the packer and the first short section is smaller than the distance between the packer and the second short section.

[0015] According to a second aspect of the present invention, a method for removing a packer using a removal device as described above is provided, comprising the following steps:

[0016] S1. The lowering mechanism is set into the wellbore via the packer;

[0017] S2. The removal mechanism enters the tubing through the safety valve and increases the pressure in the pressure regulating chamber to open the centralizer and engage it on the first short section.

[0018] S3. Continue to apply pressure to fully open the cutter and rotate the drill rod to perform a cutting operation to remove the packer.

[0019] In one embodiment, the following steps are included:

[0020] When the stabilizer is not engaged with the first short section, the removal mechanism continues to fall until it abuts against the second short section through the cutter. The drill pipe is then lifted to align the stabilizer axially with the first short section, thereby allowing the cutter to perform a cutting operation to remove the packer.

[0021] Compared with the prior art, the advantages of the present invention are as follows:

[0022] Firstly, this invention enables the drill pipe centralizer to axially align and effectively engage with the first short section of the tubing during the tubing string insertion process. This ensures that the cutter can move smoothly and accurately to the predetermined position, achieving precise positioning of the cutter and ensuring that the cutter can perform cutting operations smoothly downhole, thereby further achieving the purpose of removing the packer.

[0023] Secondly, the present invention can limit the movement of the drill pipe within the tubing by having the second short section of the tubing abut against the cutter on the drill pipe. Furthermore, by raising the drill pipe by a casing distance, the cutter can accurately reach the predetermined position within the tubing again, which facilitates subsequent cutting operations and effectively improves the success rate of packer removal.

[0024] Thirdly, this invention ensures the smooth insertion of the tubing and drill pipe into the wellbore, and also ensures the cutter moves smoothly to its predetermined position, thereby improving the positioning accuracy and cutting quality of the cutter in the packer removal device. Furthermore, this invention can utilize commercially available hydraulic cutters and hydraulic centralizers, effectively reducing downhole operation costs. Additionally, the invention's advantage of tool reusability further reduces downhole operation costs. Attached Figure Description

[0025] The invention will now be described in detail with reference to the accompanying drawings, in which:

[0026] Figure 1 A schematic cross-sectional view of a packer removal device according to the present invention is shown.

[0027] Figure 2 for Figure 1 A partial view showing the structure of the centralizer in the packer removal device of the present invention;

[0028] Figure 3 for Figure 1 A partial view showing the structure of the first short section in the packer removal device of the present invention.

[0029] In the accompanying drawings, the same parts use the same reference numerals. The drawings are not drawn to scale. Detailed Implementation

[0030] To make the technical solutions and advantages of the present invention clearer, exemplary embodiments of the present invention will be described in further detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not an exhaustive list of all embodiments. Furthermore, without conflict, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0031] In the description of this invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature.

[0032] In this invention, unless otherwise explicitly specified and limited, the terms "installation", "connection", "linking", "fixing", etc., 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.

[0033] Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0034] Directional terms such as "upstream," "above," or similar terms refer to the direction closer to the wellhead, i.e. Figure 1 The direction from the top of the wellhead. Directional terms such as "downstream," "below," or similar terms refer to the direction away from the wellhead, i.e. Figure 1 The bottom direction.

[0035] The invention will now be further described with reference to the accompanying drawings.

[0036] Figure 1 A schematic cross-sectional view of a packer removal device 100 according to the present invention is shown.

[0037] Figure 2 for Figure 1 A partial view showing the structure of the centralizer 22 in the packer removal device 100 of the present invention;

[0038] Figure 3 for Figure 1 A partial view showing the structure of the first section 12 in the packer removal device 100 of the present invention.

[0039] According to a first aspect of the invention, a packer removal device 100 is provided, which includes a lowering mechanism. For example... Figure 1 and 3 As shown, the lowering mechanism includes a tubular column 11, a first short section 12 extending radially outward from the tubular column 11, and a packer 13 disposed outside the tubular column 11. Preferably, the packer 13 is arranged at a distance from the first short section 12, and the packer 13 is located below the first short section 12.

[0040] In this invention, the packer 13 is preferably a permanent packer.

[0041] In one embodiment, the lowering mechanism is configured to be smoothly seated within the wellbore 30 via the packer 13.

[0042] According to the present invention, the packer removal device 100 further includes a removal mechanism used in conjunction with the downhole mechanism. Preferably, the removal mechanism is capable of entering the downhole mechanism and smoothly removing the packer 13 downhole, as described below.

[0043] In one embodiment, such as Figure 1 and 2 As shown, the removal mechanism includes a drill pipe 21, a centralizer 22 sleeved on the outside of the drill pipe 21, and a cutter 23 disposed on the lower end face of the drill pipe 21. Preferably, during the process of running the drill pipe 21, the centralizer 22 can form a stable engagement with the first short section 12 to further achieve the purpose of accurately positioning the cutter 23, thereby ensuring that the cutter 23 can smoothly cut the tubing string 11, and thus successfully remove the packer 13 on the tubing string 11 downhole, which helps to facilitate subsequent unsealing or sidetracking re-drilling of the wellbore.

[0044] In one specific embodiment of the present invention, the distance between the centralizer 22 and the cutter 23 on the tubing string 11 is equal to the distance between the first short section 12 on the drill pipe 21 and the packer 13. Therefore, when the centralizer 22 on the drill pipe 21 and the first short section 12 on the tubing string 11 are axially aligned and effectively engaged, the cutter 23 can move smoothly to below the packer 13, thereby achieving precise positioning of the cutter 23 and ensuring that the cutter 23 can perform cutting operations smoothly downhole.

[0045] In this invention, the stabilizer 22 is preferably a hydraulic stabilizer; the cutter 23 is preferably a hydraulic cutter. Preferably, both the stabilizer 22 and the cutter 23 can open outward under external pressure (i.e., open state), and both the stabilizer 22 and the cutter 23 can retract and return to their original position without pressure (i.e., retracted state).

[0046] According to the present invention, such as Figure 1 As shown, a radially inwardly extending safety valve 14 is also provided on the tubing 11. Preferably, when in the retracted state, the outer diameters of both the centralizer 22 and the cutter 23 are smaller than the inner diameter of the safety valve 14. Therefore, under no pressure, the centralizer 22 and the cutter 23 are in the retracted state and can pass smoothly through the safety valve 14.

[0047] This method allows the removal mechanism to be more easily coordinated with the lowering mechanism within the confined space of the wellbore 30, thereby improving the success rate of removing the permanent packer. Furthermore, the invention can ensure that the drill pipe 21 can be smoothly lifted or lowered into the tubing string 11 by retracting the centralizer 22 and the cutter 23. Additionally, the invention offers advantages such as low operating costs and reusable tools.

[0048] In one embodiment, such as Figure 1 As shown, a pressure regulating chamber 211 is formed inside the drill pipe 21. Preferably, both the stabilizer 22 and the cutter 23 are configured to open under the pressure of the pressure regulating chamber 211, that is, by pressurizing the pressure regulating chamber 211, the stabilizer 22 and the cutter 23 are sequentially opened within the tubing 11.

[0049] In a preferred embodiment of the present invention, the opening pressure of the stabilizer 22 is lower than that of the cutter 23. Preferably, the opening state of the stabilizer 22 and the cutter 23 in the tubing 11 can be controlled by adjusting the pressure in the pressure regulating chamber 211, thereby ensuring that the drill pipe 21 can smoothly reach the predetermined position in the tubing 11, thus improving the positioning accuracy of the cutter 23 in the tubing 11 to facilitate precise cutting, and further improving the success rate of removing the permanent packer.

[0050] Preferably, the safety valve 14 is located upstream of the first short section 12.

[0051] When the drill pipe 21 enters the tubing 11, the pressure regulating chamber 211 is in a pressureless state, and both the centralizer 22 and the cutter 23 are in a retracted state. Therefore, the drill pipe 21 can smoothly pass through the safety valve 14 and continue to move into the tubing 11.

[0052] After the stabilizer 22 of the drill pipe 21 passes through the safety valve 14, pressure is applied to the pressure regulating chamber 211 to make the stabilizer 22 fully open and abut against the inner wall of the tubing string 11, thereby playing a good stabilizing role for the cutter 23, ensuring that the cutter 23 can always be in a centered state in the tubing string 11, and further playing the purpose of protecting the tubing string 11.

[0053] When the centralizer 22 of the drill pipe 21 is axially aligned and effectively engaged with the first short section 12 on the tubing 11, the packer 13 is removed by continuing to pressurize the pressure regulating chamber 211 to fully open the cutter 23 and by rotating the drill pipe 21 to perform a cutting operation (i.e., the cutter 23 cuts the tubing 11).

[0054] In this invention, when the centralizer 22 on the drill pipe 21 is aligned with and effectively engaged with the first short section 12 on the tubing string 11, the cutter 23 can accurately reach the predetermined position below the packer 13, thereby ensuring that the cutter 22 can make accurate cuts within the tubing string 11, further improving the success rate of removing the permanent packer.

[0055] According to the present invention, such as Figure 1As shown, a second short section 15 extending radially inward is also provided on the tubing 11. Preferably, the second short section 15 is located downstream of the packer 13, and the cutter 23 is configured to abut against the second short section 15, thereby facilitating subsequent remedial cutting measures to further improve the success rate of removing the permanent packer, as described below.

[0056] In one embodiment of the present invention, the distance between the packer 13 and the first short section 12 is smaller than the distance between the packer 13 and the second short section 15. Preferably, the difference between the distance between the packer 13 and the first short section 12 and the distance between the packer 13 and the second short section 15 is one casing distance. Therefore, when the cutter 23 abuts against the second short section 15, lifting it by one casing distance ensures that the cutter 23 smoothly reaches the predetermined position. In the present invention, one casing distance can be determined according to actual downhole requirements, typically 10-11 mm.

[0057] In this invention, during the drilling process, if the stabilizer 22 is not fully opened or cannot open to the required size after pressurization of the pressure regulating chamber 211, the stabilizer 22 on the drill rod 21 will not be able to engage with the first short section 12 of the tubing string 11. Therefore, the drill rod 21 will continue to descend within the tubing string 11 until the cutter 23 on the drill rod 21 abuts against the second short section 15 of the tubing string 11.

[0058] Subsequently, the packer 13 is removed by raising the drill rod 21 by a casing distance and rotating the drill rod 21 to cause the cutter 23 to perform a cutting operation.

[0059] Preferably, after raising the casing by one casing distance, the stabilizer 22 on the drill pipe 21 is aligned axially with the first short section 12 on the tubing string 11, and the cutter 23 can also smoothly reach the predetermined position (i.e. below the packer 13), thereby ensuring that the cutter 22 can be accurately positioned within the tubing string 11, so as to improve the success rate of removing the permanent packer.

[0060] This allows the drilling personnel to accurately determine the specific position of the drill pipe 21 within the tubing string 11 while on the surface, and ensures that the cutter 22 smoothly reaches the predetermined position within the drill string 11 by manually raising it a fixed distance (casing distance), thus facilitating subsequent cutting operations. Furthermore, this method ensures that the cutter 22 can perform cutting operations smoothly and accurately, further improving the success rate of removing the permanent packer.

[0061] According to a second aspect of the present invention, a method for removing a packer 13 using a removal device 100 as described above is provided, comprising the following steps:

[0062] First, the lowering mechanism in the packer removal device 100 is lowered and set into the wellbore 30 by the packer 13.

[0063] Then, the removal mechanism in the packer removal device 100 is lowered, and the drill pipe 21 in the removal mechanism enters the tubing 11 through the safety valve 14.

[0064] Preferably, when the drill pipe 21 enters the tubing 11, the pressure regulating chamber 211 is in a pressureless state, and at this time, both the centralizer 22 and the cutter 23 are in a retracted state. Therefore, the drill pipe 21 can smoothly pass through the safety valve 14 and continue to move into the tubing 11.

[0065] Then, by pressurizing the pressure regulating chamber 211 (i.e. increasing the pressure inside the pressure regulating chamber 211), the stabilizer 22 on the drill pipe 21 is fully opened and comes into contact with the inner wall of the tubing string 11.

[0066] Preferably, the stabilizer 22 is in the open state at this time, so as to play a good stabilizing role for the cutter 23, ensuring that the cutter 23 can always be centered in the tubing 11, and further protecting the tubing 11.

[0067] Subsequently, as the drill pipe 21 continues to descend within the tubing 11, the stabilizer 22 on the drill pipe 21 will engage with the first short section 12 on the tubing 11.

[0068] Preferably, the cutter 23 is positioned below the packer 13 at this time, thereby ensuring that the cutter 22 can accurately reach the predetermined position within the tubing 11, thus improving the success rate of removing the permanent packer.

[0069] Finally, continue to apply pressure to fully open the cutter 23 and put it in the open state. Rotate the drill rod 21 to force the cutter 23 to perform a cutting operation, thereby achieving the purpose of removing the packer 13.

[0070] In one embodiment, the following steps are included:

[0071] During the lowering of drill pipe 21, after pressurization into the pressure regulating chamber 211, if the centralizer 22 fails to fully open or cannot open to the required size and thus cannot be secured to the first short section 12 of the tubing string 11, drill pipe 21 will continue to fall until the cutter 23 on drill pipe 21 abuts against the second short section 15 of tubing string 11. Subsequently, by raising drill pipe 21 by a casing distance and rotating drill pipe 21 to induce the cutter 23 to perform a cutting operation, the packer 13 is removed.

[0072] Preferably, in the above-described case, raising the casing by one casing distance ensures that the centralizer 22 on the drill pipe 21 and the first short section 12 on the tubing string 11 are axially aligned. Accordingly, the cutter 23 will also smoothly reach the predetermined cutting position, thereby ensuring that the cutter 22 can be accurately positioned within the tubing string 11, thus improving the success rate of removing the permanent packer.

[0073] Compared with existing technologies, the advantages of this invention are:

[0074] Firstly, the present invention enables the drill pipe 21's centralizer 22 to be axially aligned and effectively engaged with the first short section 12 of the tubing 11 during the tubing string 11 insertion process, thereby ensuring that the cutter 23 can move smoothly and accurately to the predetermined position, achieving the purpose of precise positioning of the cutter 23, and thus ensuring that the cutter 23 can smoothly perform cutting operations downhole, further achieving the purpose of removing the packer 13.

[0075] Secondly, the present invention can limit the movement of the drill rod 21 within the tubing 11 by having the second short section 15 of the tubing 11 abut against the cutter 23 on the drill rod 21. Furthermore, by raising the drill rod 21 by a casing distance, the cutter 23 can accurately reach the predetermined position within the tubing 11 again, which facilitates subsequent cutting operations and effectively improves the success rate of removing the packer 13.

[0076] Thirdly, this invention ensures the smooth insertion of the tubing string 11 into the wellbore 30 and the drill pipe 21 into the tubing string 11, and also ensures the cutter 23 moves smoothly to the predetermined position, thereby improving the positioning accuracy and cutting quality of the cutter 23 by the packer removal device 100. Furthermore, this invention can utilize commercially available hydraulic cutters and hydraulic centralizers, effectively reducing downhole operation costs. Additionally, the invention's advantage of tool reusability further reduces downhole operation costs.

[0077] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Those skilled in the art can easily make changes or modifications within the scope of the present invention, and such changes or modifications should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A packer removal device, comprising: The lowering mechanism includes a tubing string (11), a first short section (12) extending radially outward from the tubing string (11), and a packer (13) disposed downstream of the first short section (12) for setting within the wellbore (30). The removal mechanism for inserting into the tubing string (11) includes a drill pipe (21), a stabilizer (22) sleeved on the drill pipe (21) and used to engage with the first short section (12), and a cutter (23) disposed at the lower end face of the drill pipe (21). A pressure regulating chamber (211) is formed in the drill pipe (21). The stabilizer (22) and the cutter (23) are both configured to open under the pressure of the pressure regulating chamber (211). The stabilizer (22) is configured as a hydraulic stabilizer. The opening pressure of the stabilizer (22) is smaller than the opening pressure of the cutter (23). The distance between the stabilizer (22) and the cutter (23) is equal to the distance between the first short section (12) and the packer (13).

2. The removal device for a packer of claim 1, wherein, A radially inwardly extending safety valve (14) is also provided on the tubing (11), the safety valve (14) being located upstream of the first short section (12).

3. The packer removal device according to claim 2, characterized in that, The outer diameters of the stabilizer (22) and the cutter (23) are both smaller than the inner diameter of the safety valve (14) in the contracted state.

4. The packer removal device according to claim 3, characterized in that, The tubular column (11) is also provided with a second short section (15) extending radially inward for abutting against the cutter (23), the second short section (15) being located downstream of the packer (13).

5. The packer removal device according to claim 4, characterized in that, The distance between the packer (13) and the first short section (12) is smaller than the distance between the packer (13) and the second short section (15).

6. A method for removing a packer using the removal device according to any one of claims 4 to 5, comprising the following steps: S1. The lowering mechanism is set into the wellbore (30) by the packer (13); S2. The removal mechanism enters the tubing (11) through the safety valve (14) and increases the pressure in the pressure regulating chamber (211) to open the centralizer (22) and lock it onto the first short section (12); S3. Continue to pressurize to fully open the cutter (23) and rotate the drill rod (21) to perform a cutting operation to remove the packer (13).

7. The method according to claim 6, characterized in that, Includes the following steps: When the stabilizer (22) is not engaged with the first short section (12), the removal mechanism continues to fall until it abuts against the second short section (15) through the cutter (23). The stabilizer (22) is aligned axially with the first short section (12) by lifting the drill rod (21), thereby removing the packer (13) by cutting with the cutter (23).

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