Staggered casing centralizing and reinforcing tool and method

Abstract

The invention discloses a staggered casing centralizing and reinforcing tool and method, and the tool comprises a central pipe, and the outer side of the central pipe is provided with a lining; the central pipe is provided with two sealing sleeves which are respectively positioned above and below the dislocated part of the casing pipe, and the two sealing sleeves are used for sealing and separating the dislocated part of the casing pipe to form a sealing cavity; side holes for injecting cement into the sealing cavity are formed in the lining and the central pipe; the problems that according to an existing broken casing pipe repairing method, an upper casing pipe and a lower casing pipe cannot be aligned in the cement squeezing process, the upper casing pipe and the lower casing pipe are not concentric after cement is solidified, and follow-up tools cannot enter the lower casing pipe are effectively solved.

Description

Technical Field

[0001] This disclosure relates to the downhole tool part in the major overhaul construction of oilfield development, and specifically relates to the repair of broken casings. Background Art

[0002] Currently, expansion tubes are used to subsidize broken casings, but it is impossible to squeeze cement into the broken parts for reinforcement, and the inner diameter of the casing decreases after subsidization, affecting subsequent construction. Summary of the Invention

[0003] In view of this, this disclosure provides a tool for straightening and reinforcing broken casings, which solves the problem that the current method of using expansion tubes to straighten and reinforce broken casings has a short effective period after subsidization because it is impossible to squeeze cement into the broken position for reinforcement.

[0004] In addition, this disclosure also provides a method for straightening and reinforcing broken casings using the above tool.

[0005] In the first aspect, the tool for straightening and reinforcing broken casings includes: A central tube, with a bushing arranged outside the central tube; Two sealing sleeves are arranged on the central tube, respectively above and below the broken part of the casing. The two sealing sleeves form a sealed cavity by sealing off at the broken part of the casing; The bushing and the central tube are provided with side holes for injecting cement into the sealed cavity.

[0006] In this disclosure and possible embodiments, the bushing is a resin tube.

[0007] In this disclosure and possible embodiments, the resin tube is a Pe nylon tube.

[0008] In this disclosure and possible embodiments, the two sealing sleeves are either both sealing rubber cylinders, or both sealing rubber rings, or one is a sealing rubber cylinder and the other is a sealing rubber ring.

[0009] In this disclosure and possible embodiments, a sealing ring is arranged between the bushing and the central tube.

[0010] In this disclosure and possible embodiments, sealing grease is injected between the bushing and the central tube.

[0011] In this disclosure and possible embodiments, the lower end of the central tube is connected to a guiding body.

[0012] In this disclosure and possible embodiments, the upper end of the central tube is connected to a releasing joint.

[0013] In the second aspect, the method for straightening and reinforcing broken casings includes: Use the tool described in the first aspect to straighten and reinforce the misaligned part of the casing.

[0014] In the present disclosure and possible embodiments, lower the misaligned casing straightening and reinforcing tool into the well, align the sealing cavity with the misaligned part of the casing, inject cement into the sealing cavity through the side holes, wait for the cement to solidify, separate the central tube from the bushing, and remove the central tube and the sealing sleeve.

[0015] In the present disclosure and possible embodiments, after removing the central tube, drill and grind the bushing to fully restore the casing diameter at the misaligned part.

[0016] The present disclosure has the following beneficial effects: The misaligned casing straightening and reinforcing tool of the present disclosure adopts a double-layer structure design of an outer bushing and an inner central tube. When injecting cement into the misaligned part, the tool is left in the well to keep the casing in a straightened state. After the cement solidifies, the central tube is removed, and the outer bushing is left in the well. Then, the outer bushing left in the well is drilled and ground, so as to fully restore the inner diameter of the casing, achieving the purpose of injecting cement to stabilize the fracture after straightening the misaligned casing, and avoiding the problems that the upper and lower casings cannot be aligned during squeezing cement in the past, resulting in non-concentric upper and lower casings after the cement solidifies and the tool cannot enter the lower casing. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Through the following description of the embodiments of the present disclosure with reference to the accompanying drawings, the above and other objects, features, and advantages of the present disclosure will become clearer. In the drawings: Figure 1 is a schematic structural diagram of the misaligned casing straightening and reinforcing tool according to an embodiment of the present disclosure; Figure 2 is Figure 1 the A-A view in EMBODIMENTS

[0018] The following is a description of the present disclosure based on embodiments. However, it should be noted that the present disclosure is not limited to these embodiments. In the following detailed description of the present disclosure, some specific details are described in detail. However, for the parts that are not described in detail, those skilled in the art can also fully understand the present disclosure.

[0019] In addition, those of ordinary skill in the art should understand that the provided drawings are only for illustrating the purposes, features, and advantages of the present disclosure, and the drawings are not actually drawn to scale. At the same time, unless the context clearly requires otherwise, the words such as "including" and "comprising" in the whole specification and claims should be interpreted as having the meaning of including rather than exclusive or exhaustive meaning; that is, it is the meaning of "including but not limited to".

[0020] To make the objectives, technical solutions and advantages of the present invention more clear and understandable, the following provides further detailed descriptions of the present invention according to the accompanying drawings and by way of examples.

[0021] Before listing the embodiments, first explain the technical concept of the casing straightening and reinforcement tool of the present invention: a double-layer structure is formed between the inner central tube and the outer liner. During the process of injecting cement into the broken casing, the inner central tube continuously straightens the casing and provides a supporting effect on the liner to prevent the liner from deforming and avoid the misalignment of the broken casing during the cement solidification process. When the cement is completely solidified, since the central tube and the liner form a double-layer structure, they can be separated from each other, and the central tube can be removed without being unable to be taken out due to the solidification of the cement. What remains in the well is only the liner. After the other components of the tool are taken out with the central tube and the liner is drilled and milled off, the diameter of the casing at the broken part can be completely restored, which does not affect the subsequent smooth lowering of the tool at all.

[0022] Figure 1 is a schematic structural diagram of the broken casing straightening and reinforcement tool according to an embodiment of the present disclosure; in combination with Figure 1 As shown: the broken casing straightening and reinforcement tool includes a central tube 3, and a bushing 4 is arranged outside the central tube 3. Two sealing sleeves are arranged on the central tube 3. After the tool of this embodiment is lowered into the well, the two sealing sleeves are respectively located above and below the broken part of the casing, ensuring that the two sealing sleeves form a sealed cavity at the broken part of the casing, and side holes for injecting cement into the sealed cavity are arranged on the bushing and the central tube, and cement is injected into the sealed cavity through the side holes; during the cement solidification process, due to the straightening effect of the central tube 3, the alignment of the broken part of the casing can be fully guaranteed, preventing the upper and lower casings from being non-concentric after the cement solidifies; after the cement solidifies, since the bushing and the central tube are only sleeved, the bushing and the central tube can be separated, and the separated central tube and the sealing sleeves are taken out, and the cement ring formed after solidification can continue to reinforce the broken part of the casing after straightening, achieving the purpose of perfectly repairing the broken casing.

[0023] In Figure 1 of this embodiment, the bushing selected is a resin tube, and more preferably, the resin tube is a Pe nylon tube; the reason is that the resin tube is easier to drill and mill. After taking out components such as the central tube, the remaining liner is continuously drilled and milled to fully remove the residual liner, and the inner diameter of the casing at the broken part can be completely restored, facilitating the subsequent tool to smoothly enter the lower casing.

[0024] In Figure 1 of this embodiment, the two sealing sleeves can both be sealing rubber cylinders or both be sealing rubber rings. Preferably, the sealing rubber cylinder 6 is located above and the sealing rubber ring 2 is located below. When injecting cement into the sealed cavity, a pressure difference is formed between the two sealing sleeves, and under the action of the pressure difference, the two sealing sleeves expand and seal to form a sealed cavity.

[0025] In Figure 1 , an O-ring 5 is arranged between the bushing and the central pipe of this embodiment. More preferably, sealing grease is injected between the bushing and the central pipe, aiming to prevent part of the cement slurry from entering the annular gap between the bushing and the central pipe during the process of injecting cement into the sealing cavity, increasing the difficulty of separating the two subsequently.

[0026] In Figure 1 , the lower end of the central pipe of this embodiment is connected to a guiding body 1. The guiding body can adopt general techniques in the art, specifically a tapered tip, through which the tool can smoothly enter the broken part of the casing. Preferably, as Figure 2 shown, a number of ridges or protrusions are axially arranged on the side wall of the guiding body 1. Correspondingly, the sealing sleeve arranged at the lower end of the central pipe 3 is a Y-shaped sealing rubber ring, and the Y-shaped sealing rubber rings are limited by the ridge or protrusion structure.

[0027] In Figure 1 , the upper end of the central pipe of this embodiment is connected to a releasing joint 8, and is connected to the drill pipe through this releasing joint, so as to achieve the purpose of lowering the whole tool into the well with the drill pipe. Preferably, the central pipe 3 is connected to the releasing joint 8 through a connecting pipe 7, and then a sealing rubber cylinder 6 is arranged on the connecting pipe 7, aiming to facilitate assembly and processing.

[0028] A method for straightening and strengthening a broken casing by using the broken casing straightening and strengthening tool of the embodiment of the present disclosure. The core is to lower the broken casing straightening and strengthening tool into the well, and make the sealing cavity correspond to the broken part of the casing, inject cement into the sealing cavity through the side hole, wait for the cement to solidify, separate the central pipe from the bushing, and take out the central pipe and the sealing sleeve.

[0029] Preferably, after taking out the central pipe, grind the bushing to completely restore the diameter of the casing at the broken part.

[0030] The process of casing misalignment straightening and reinforcement is as follows: The whole tool is lowered into the well along with the drill pipe. The liner 4 of the tool is made of Pe nylon pipe. The guiding body 1 guides the whole tool into the lower offset casing. Since the outer diameter of the tool is comparable to the inner diameter of the casing, it forces the upper and lower casings to align coaxially. After confirming that the middle part of the Pe nylon pipe of the tool is located at the misalignment position, start the pump to squeeze and inject cement. Under the action of pressure difference, the upper sealing rubber cylinder and the lower Y-shaped sealing rubber ring expand and seal, so that the cement enters the misaligned part from the side holes of the tool. After the cement injection is completed, remove the pressure difference applied to the upper sealing rubber cylinder and the lower Y-shaped sealing rubber ring, and the expansion seal of the sealing rubber cylinder and the Y-shaped sealing rubber ring fails. Drop the ball and release the tool string, and the whole tool still remains in the well. After the cement solidifies, lower a special fishing tool to fish the release joint 8 of the tool, lift the fishing central pipe 3, and the central pipe 3 separates from the Pe nylon pipe. The Pe nylon pipe remains in the well, and the rest of the tool is completely lifted out of the wellbore. Lower a milling tool to mill the nylon bushing remaining in the well to restore the passage inside the casing. Since the upper and lower casings at the misalignment position have been solidified by cement, the misaligned casing is no longer in a movable state, achieving the purpose of completely straightening and reinforcing the misaligned casing and creating conditions for subsequent construction.

[0031] Application Example When logging with a sixteen-arm tool in a certain well, it encountered resistance at 943 meters. Lower a Φ116mm lead mold for printing, and the printing depth is 942.75m. The imprint shows casing misalignment, and the minimum internal diameter is Φ85mm. Use a 80-118mm milling cone to mill and expand the diameter step by step. Finally, use a 120mm milling cone to mill until there is no sticking when lifting and lowering. Lower the straightening and reinforcement tool of the present disclosure into the wellbore at the casing misalignment point using tubing, slowly apply pressure to make the guiding body gradually enter the lower casing, verify the data, align the middle position of the Pe nylon sleeve with the misalignment position, lock the hook of the workover rig, and ensure that the tool is in a static state. Start the pump to squeeze and inject cement. Under the action of pressure difference, the upper sealing rubber cylinder and the lower Y-shaped sealing rubber ring expand and seal, so that the cement enters the misaligned part from the side holes of the tool. After the cement slurry injection is completed, drop the ball and release the tool string, and the tool remains in the well. Wait for 24 hours for setting. After connecting the drill pipe and then lifting 38t, the tool mandrel is lifted out. Lower a 120mm milling cone to drill and mill the bushing remaining in the well to restore the internal diameter of the sleeve and ensure the smooth passage for subsequent construction.

[0032] The above-described embodiments are only for expressing the implementation modes of the present disclosure, and the description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent of the present disclosure. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present disclosure, several deformations, equivalent replacements, improvements, etc. can be made, and these all belong to the protection scope of the present disclosure. Therefore, the protection scope of the patent of the present disclosure should be subject to the appended claims.

Claims

1. A misaligned casing centralizing and strengthening tool, characterized in that, Comprising: A central tube, with a bushing arranged outside the central tube; Two sealing sleeves are arranged on the central tube, respectively above and below the casing offset part. The two sealing sleeves enclose and form a sealing cavity at the casing offset part; Side holes for injecting cement into the sealing cavity are arranged on the bushing and the central tube.

2. The offset casing straightening and strengthening tool according to claim 1, characterized in that: The bushing is a resin tube.

3. The offset casing straightening and strengthening tool according to claim 1 or 2, characterized in that: The resin tube is a Pe nylon tube; and / or, The two sealing sleeves are either both sealing rubber cylinders, or both sealing rubber rings, or one is a sealing rubber cylinder and the other is a sealing rubber ring.

4. The offset casing straightening and strengthening tool according to claim 3, characterized in that: A sealing ring is arranged between the bushing and the central tube.

5. The offset casing straightening and strengthening tool according to claim 4, characterized in that: Sealing grease is injected between the bushing and the central tube.

6. The offset casing straightening and strengthening tool according to claim 1, 2, 4 or 5, characterized in that: The lower end of the central tube is connected to a guiding body.

7. The offset casing straightening and strengthening tool according to claim 6, characterized in that: The upper end of the central tube is connected to a releasing joint.

8. A method for straightening and strengthening a misaligned casing, characterized in that, Comprising: Using the tool according to any one of claims 1-7 to straighten and strengthen the casing offset part.

9. The offset casing straightening and strengthening method according to claim 8, characterized in that: Lower the offset casing straightening and strengthening tool into the well, and make the sealing cavity correspond to the casing offset part. Inject cement into the sealing cavity through the side holes. After the cement solidifies, separate the central tube from the bushing, and take out the central tube and the sealing sleeves.

10. The offset casing straightening and strengthening method according to claim 9, characterized in that: After taking out the central tube, drill and grind the bushing to completely restore the casing diameter at the offset part.

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