In-situ repairing tool and repairing method for leakage of underground tubular column connector

Abstract

The invention relates to a downhole tubular column connector leakage in-situ repairing tool and method, the repairing tool comprises a center pipe, an air bag, two flexible sealing pieces and two outer pipe movement mechanisms, the center pipe is vertically arranged, and two inner pressure hole sets are formed in the center pipe at intervals; the two outer pipe movement mechanisms are coaxially arranged on the central pipe in a sleeving manner respectively, and outer pressure hole groups are formed in the two outer pipe movement mechanisms respectively; the opposite ends of the two outer pipe movement mechanisms are fixedly sleeved with the air bag, and a capsule string set containing repairing liquid is installed on the air bag. The two sealing pieces are fixedly arranged outside the center pipe in a sleeving mode and located outside the two outer pipe movement mechanisms respectively, and the air bag is located between the two sealing pieces and located outside the two outer pressure hole sets and the two inner pressure hole sets respectively. The method has the beneficial effects that the problem of oil sleeve annulus pressure caused by pipe column connector micro leakage can be effectively solved, field operation is convenient, the pipe column drift diameter and follow-up operation are not affected, and cost is greatly saved.

Description

Technical Field

[0001] The invention relates to the technical field of oil production engineering, and in particular to an in-situ repair tool and a repair method for a downhole pipe column joint leakage. Background Art

[0002] Existing deep wells, ultra-deep wells, and gas storage wells are subject to frequent opening and closing, strong injection and strong production, high temperature and high pressure, and other working conditions. The completion string is composed of multiple components such as safety valves, oil pipe strings, and packers. There are many risk points, which leads to frequent pressure in the A annulus of the gas well. For example, the highest pressure in the A annulus of the gas storage well is ≥5MPa, accounting for 61.5%. This is mainly because the threaded joints of the injection and production strings of the gas storage are prone to sealing failure under the action of alternating loads, resulting in pressure in the annulus of the oil casing of the gas storage well, and the first well barrier completely fails, which makes production extremely safe. In order to restore the first well barrier, the best approach is to replace the pipe string and repair the well, but the cost of engineering operations is too high, and the well pressure operation is very likely to cause reservoir pollution, resulting in a decrease in production. Therefore, a chemical plugging glue has appeared on the market. At present, chemical plugging glue is mostly used to plug the formation after casing perforation and restore the sealing integrity of the cement ring outside the casing. The injection of glue to plug the oil casing annulus is only used in the low-pressure environment of heavy oil thermal recovery wells in Shengli Oilfield. After plugging, a ring column of hundreds of meters is formed in the oil casing annulus, which is harder than the cement ring. The applicability of annular injection plugging in high-pressure dynamic load environments such as deep wells, ultra-deep wells, and gas storage wells is unclear. Moreover, after the oil casing is plugged, it will cause the complexity of the later pipe string repair.

[0003] The completion string uses an air-tight threaded structure, and leaks in air-tight threaded joints often result in leak point pressures. Leakage will occur above the leak point pressure, and no leakage will occur below the leak point pressure. Therefore, most leakages in the completion string joints are micro-leakages, and the cost of replacing the string is high. However, controlling the leak point pressure will reduce the injection and production operating pressure, significantly reducing production efficiency.

[0004] The main problems of the existing technology are: 1) the cost of replacing the tubing string for well repair is high and it is easy to cause reservoir pollution; 2) the existing chemical plugging glue is injected into the annulus for plugging, the amount is large and the cost is higher, and it is easy to cause the later well repair and tubing string repair to be complicated and difficult. Therefore, the present invention provides an underground in-situ repair tool and repair technology method without moving the tubing string, which greatly saves costs, realizes underground in-situ repair, and ensures the tubing string diameter without affecting subsequent production operations. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide an in-situ repair tool and a repair method for a downhole pipe column joint leakage, aiming to solve the problems in the prior art.

[0006] The technical solution of the present invention to solve the above technical problems is as follows:

[0007] A downhole tubular joint leakage in-situ repair tool, comprising a center tube, an airbag, two flexible sealing members and two outer tube movement mechanisms, wherein the center tube is vertically arranged and has two groups of internal pressure hole groups arranged thereon at intervals; the two outer tube movement mechanisms are respectively coaxially sleeved on the center tube, and are respectively provided with external pressure hole groups thereon, and can be moved to the two groups of external pressure hole groups to be connected with or staggered with the two groups of internal pressure hole groups respectively; the airbag is fixedly sleeved outside the opposite ends of the two outer tube movement mechanisms, and a capsule string group filled with repair fluid is installed thereon; the two sealing members are fixedly sleeved outside the center tube, and are respectively located outside the two outer tube movement mechanisms, and the airbag is located between the two sealing members, and is respectively located outside the two groups of external pressure hole groups and the two groups of internal pressure hole groups.

[0008] The beneficial effects of the present invention are as follows: during the repair process, first, the upper end of the central tube is connected to the well repair pipe string, and the lower end is connected to the positioner, and is lowered into the micro-gap of the leaking pipe string to be repaired, and the lower end of the central tube is sealed at the same time; secondly, fluid is injected into the central tube to move the two outer tube movement mechanisms to the two groups of outer pressure hole groups thereon to be connected with the two groups of inner pressure hole groups on the central tube respectively, and at the same time, the two outer tube movement mechanisms squeeze the two seals to make the two seals close to the inner wall of the leaking pipe string, so that an annular closed space is formed between the leaking pipe column joint disposed outside the leaking pipe column and the central tube and the two seals; then, fluid is continuously injected into the central tube to make the airbag expand and squeeze the capsule string group thereon, the capsule string group is broken and the repair fluid inside it flows out and mixes in the annular closed space; finally, fluid is continuously injected into the central tube, and the mixed repair fluid forms a protective film at the micro-gap under the squeezing of the airbag, so that the repair efficiency is high and the service life of the oil and gas well is extended.

[0009] The present invention can effectively solve the problem of casing annulus pressure caused by micro-leakage of the pipe column joint, is convenient for on-site operation, does not affect the pipe column diameter and subsequent operations, and greatly saves costs.

[0010] Based on the above technical solution, the present invention can also be improved as follows.

[0011] Furthermore, the capsule string group includes a plurality of repair liquid A capsule strings and a plurality of repair liquid B capsule strings, and the plurality of repair liquid A capsule strings and the plurality of repair liquid B capsule strings are evenly spaced and distributed on the airbag.

[0012] The beneficial effect of adopting the above further solution is that a plurality of repair liquid A capsule strings and a plurality of repair liquid B capsule strings are distributed on the airbag at intervals, so that the repair liquids inside the airbag can be mixed evenly, thereby ensuring the quality of the repair.

[0013] Furthermore, multiple repair liquid A capsule strings and multiple repair liquid B capsule strings are respectively arranged in multiple rows along the axial extension of the airbag, and multiple rows of repair liquid A capsule strings and multiple rows of repair liquid B capsule strings are evenly spaced and alternately arranged in sequence along the circumference of the airbag.

[0014] The beneficial effect of adopting the above further solution is that multiple repair liquid A capsule strings and multiple repair liquid B capsule strings are reasonably distributed on the airbag, which can further make the repair liquid inside it evenly mixed to ensure the quality of the repair.

[0015] Furthermore, the plurality of repair liquid A capsule strings and the plurality of repair liquid B capsule strings are spirally distributed on the airbag, and the plurality of repair liquid A capsule strings and the plurality of repair liquid B capsule strings are alternately arranged in sequence.

[0016] The beneficial effect of adopting the above further solution is that multiple repair liquid A capsule strings and multiple repair liquid B capsule strings are reasonably distributed on the airbag, which can further make the repair liquid inside it evenly mixed to ensure the quality of the repair.

[0017] Further, the plurality of repair liquid A capsule strings respectively include a plurality of repair liquid A capsules, and the plurality of repair liquid B capsule strings respectively include a plurality of repair liquid B capsules.

[0018] The beneficial effect of adopting the above further solution is that the capsule string contains multiple capsules containing different repair liquids, which facilitates the uniform mixing of different repair liquids.

[0019] Furthermore, the two groups of internal pressure hole groups respectively include multiple internal pressure holes, and the multiple internal pressure holes in each group are evenly spaced on the central tube; the two groups of external pressure hole groups respectively include multiple external pressure holes, and the multiple external pressure holes in each group are evenly spaced on the corresponding outer tube movement mechanism, which are consistent in number and corresponding in position to the multiple internal pressure holes in the corresponding group.

[0020] The beneficial effect of adopting the above further scheme is that multiple internal pressure holes and multiple external pressure holes are evenly distributed, which makes it easy to utilize the pressure changes in the central tube to expand the airbag to squeeze the capsule string group on the airbag. The capsule string group ruptures to allow the repair fluid inside to flow out for pipe column repair, making repair convenient.

[0021] Furthermore, two annular grooves are arranged at intervals on the central tube, the two outer tube movement mechanisms are movably installed in the two annular grooves respectively, and the two internal pressure hole groups are distributed in the two annular grooves respectively.

[0022] The beneficial effect of adopting the above further solution is that the structural design of the central tube is reasonable, and the installation of the two outer tube movement mechanisms is convenient.

[0023] Furthermore, the two sealing members are respectively annular rubber cylinders, the airbag is an annular airbag, and the outer diameters of the two annular rubber cylinders are greater than the outer diameter of the annular airbag.

[0024] The beneficial effect of adopting the above further scheme is that the shapes of the airbag and the two rubber cylinders are reasonably designed, which is convenient for assembly on the central tube, expansion of the rubber cylinder to fit the inner wall of the pipe column, and expansion of the airbag to squeeze the capsule string group for repair work.

[0025] Furthermore, both ends of the central tube are respectively connected with joints.

[0026] The beneficial effect of adopting the above further solution is that the two joints are reasonably designed, which facilitates the connection of the workover pipe string and the positioner.

[0027] The present invention also relates to a method for in-situ repairing a downhole tubular joint leakage, which is implemented by using the in-situ repairing tool for downhole tubular joint leakage as described above, and comprises the following specific steps:

[0028] S1: The upper end of the central pipe is connected to the workover string, and the lower end is connected to the positioner, and is lowered into the micro-gap of the leaking string to be repaired, while sealing the lower end of the central pipe;

[0029] S2: injecting fluid into the central tube to move the two outer tube movement mechanisms to the point where the two groups of outer pressure holes on the outer tube are respectively connected to the two groups of inner pressure holes on the central tube, and at the same time, the two outer tube movement mechanisms squeeze the two seals to make the two seals closely attached to the inner wall of the leakage column, so that an annular closed space is formed between the leakage column joint disposed outside the leakage column and the central tube and the two seals;

[0030] S3: continue to inject fluid into the central tube to expand the airbag and squeeze the capsule string group thereon, so that the capsule string group ruptures and the repair fluid inside thereof flows out and mixes in the annular closed space;

[0031] S4: Continue to inject fluid into the central tube, and the mixed repair fluid forms a protective film at the micro gap under the squeezing of the airbag.

[0032] The beneficial effect of adopting the above further scheme is that the present invention also provides a repair method, which can effectively solve the problem of oil casing annulus pressure caused by micro-leakage of the pipe column joint, is convenient for on-site operation, does not affect the pipe column diameter and subsequent operations, and greatly saves costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a schematic diagram of the overall structure of the repair tool in the present invention;

[0034] Figure 2 It is a schematic diagram of the overall structure of the repair tool of the present invention during repair;

[0035] Figure 3 This is a schematic diagram of the first distribution scheme of the capsule string group in the present invention;

[0036] Figure 4 This is a schematic diagram of the second distribution scheme of the capsule string group in the present invention.

[0037] In the accompanying drawings, the components represented by the reference numerals are listed as follows:

[0038] 1. Upper joint; 2. Center tube; 3. Outer tube movement mechanism; 4. Upper rubber cylinder; 5. Inner pressure hole; 6. Air bag; 7. Repair fluid A capsule string; 8. Outer pressure hole; 9. Lower rubber cylinder; 10. Lower joint; 11. Leaking pipe column; 12. Leaking pipe column joint; 13. Micro gap; 14. Repair fluid B capsule string. DETAILED DESCRIPTION

[0039] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0040] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and the like are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", and the like may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0041] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0042] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0043] Example 1

[0044] like Figures 1 to 4 As shown, this embodiment provides an in-situ repair tool for downhole tubular joint leakage, including a center tube 2, an airbag 6, two flexible seals and two outer tube motion mechanisms 3, wherein the center tube 2 is vertically arranged, and two groups of internal pressure hole groups are arranged thereon at intervals; the two outer tube motion mechanisms 3 are respectively coaxially sleeved on the center tube 2, and are respectively provided with external pressure hole groups, and can be moved to the two groups of external pressure hole groups to be connected with or staggered with the two groups of internal pressure hole groups respectively; the airbag 6 is fixedly sleeved outside the opposite ends of the two outer tube motion mechanisms 3, and a capsule string group filled with repair fluid is installed thereon; the two seals are fixedly sleeved outside the center tube 2, and are respectively located outside the two outer tube motion mechanisms 3, and the airbag 6 is located between the two seals, and is located outside the two groups of external pressure hole groups and the two groups of internal pressure hole groups respectively.

[0045] During the repair process, first, the upper end of the central tube 2 is connected to the repairing pipe string, and the lower end is connected to the positioner (the positioner is preferably a magnetic positioning logging instrument in the prior art), and is lowered into the micro gap 13 of the leaking pipe string 11 to be repaired, and the lower end of the central tube 2 is sealed at the same time; secondly, fluid is injected into the central tube 2 to move the two outer tube movement mechanisms 3 to the two groups of outer pressure hole groups on it, respectively connected with the two groups of inner pressure hole groups on the central tube, and at the same time, the two outer tube movement mechanisms 3 squeeze the two seals to make the two seals and the leaking pipe string 11 The inner wall is tightly attached, so that an annular closed space is formed between the leakage column joint 12 arranged outside the leakage column 11 and the central pipe 2 and the two sealing members; then, the fluid is continuously injected into the central pipe 2 to expand the airbag 6 to squeeze the capsule string group thereon, and the capsule string group is broken and the internal repair fluid flows out and mixes in the annular closed space; finally, the fluid is continuously injected into the central pipe 2, and the mixed repair fluid forms a protective film at the micro gap 13 under the squeezing of the airbag 6, so that the repair efficiency is high and the service life of the oil and gas well is extended.

[0046] Based on the above scheme, the two external pressure hole groups need to be connected or staggered with the two internal pressure hole groups at the same time. When connected, it is ensured that the two outer tube movement mechanisms 3 can squeeze the two seals, so that an annular closed space is formed between the two seals, the center tube 2 and the leaking pipe column 11 to facilitate subsequent repair operations.

[0047] Preferably, in this embodiment, the central tube 2 is preferably a circular tubular structure, and both ends thereof are open.

[0048] Preferably, in this embodiment, the airbag 6 is preferably a rubber airbag.

[0049] It should be noted that during repair, pressure can be injected into the central tube 2 in a manner that can be imagined by those skilled in the art, for example, an air pump on the ground is connected to the interior of the central tube 2 through a pipeline.

[0050] In addition, the specific structures and matching relationships of the two outer tube movement mechanisms 3 and the two seals are based on the prior art. For the specific structure, please refer to the Chinese patent "a double rubber tube packer" with announcement number CN207315296U.

[0051] The sealing principle of the upper and lower seals is the same as that of the double-rubber tube packers sold on the market, namely: 1) a certain internal pressure is applied to the central pipe 2 (fluid is injected) to first cause the lower outer pipe movement mechanism 3 to move and squeeze the lower flexible seal, so that the seal is tightly fixed to the lower part of the inner wall of the joint of the leaking pipe column 11 and sealed; 2) continue to pressurize the central pipe, the upper outer pipe movement mechanism 3 moves and squeezes the upper flexible seal, so that the seal is tightly fixed to the upper part of the inner wall of the joint of the leaking pipe column 11 and sealed, thereby forming an annular closed space between the leaking pipe column 11, the upper and lower seals, and the repair tool, and the sealing of the repair tool is completed.

[0052] If the central tube 2 is continuously pressed, the outer tube movement mechanism 3 moves further, so that the outer pressure hole 8 is connected with the inner pressure hole 5 of the central tube; the central tube 2 is continuously pressed, the airbag 6 swells, and the arc-shaped guide of the seal makes the airbag 6 gradually approach the inner wall of the leaking pipe column joint 12, and the capsule string is broken under the gradual squeezing of the airbag, and the internal repair fluid flows out and mixes. This embodiment can effectively solve the problem of oil casing annulus pressure caused by micro-leakage of the pipe column joint, is convenient for on-site operation, does not affect the pipe column diameter and subsequent operations, and greatly saves costs.

[0053] Example 2

[0054] Based on Example 1, in this example, the capsule string group includes multiple repair liquid A capsule strings 7 (such as silicone-modified epoxy resin) and multiple repair liquid B capsule strings 14 (such as aromatic amine), and the multiple repair liquid A capsule strings 7 and the multiple repair liquid B capsule strings 14 are evenly spaced on the airbag 6.

[0055] A plurality of repair liquid A capsule strings 7 and a plurality of repair liquid B capsule strings 14 are distributed on the airbag 6 at intervals, so that the repair liquids inside thereof can be mixed evenly, thereby ensuring the quality of the repair.

[0056] Example 3

[0057] Based on Example 2, in this embodiment, multiple repair liquid A capsule strings 7 and multiple repair liquid B capsule strings 14 are respectively arranged in multiple rows along the axial extension of the airbag 6, and multiple rows of repair liquid A capsule strings 7 and multiple rows of repair liquid B capsule strings 14 are evenly spaced and alternately arranged in sequence along the circumference of the airbag 6.

[0058] The multiple repair liquid A capsule strings 7 and the multiple repair liquid B capsule strings 14 are reasonably distributed on the airbag, which can further make the repair liquid inside evenly mixed and ensure the quality of repair.

[0059] Example 4

[0060] Based on Example 2, in this example, the plurality of repair liquid A capsule strings 7 and the plurality of repair liquid B capsule strings 14 are spirally distributed on the airbag 6, and the plurality of repair liquid A capsule strings 7 and the plurality of repair liquid B capsule strings 14 are alternately arranged in sequence.

[0061] The multiple repair liquid A capsule strings 7 and the multiple repair liquid B capsule strings 14 are reasonably distributed on the airbag 6, which can further make the repair liquid inside it evenly mixed to ensure the quality of the repair.

[0062] The above-mentioned Embodiment 3 and Embodiment 4 are parallel solutions.

[0063] In addition, the total volume ratio of the repair liquid A in the plurality of the repair liquid A capsule strings 7 to the total volume of the repair liquid B in the plurality of the repair liquid B capsules 14 is 1:3, which is a reasonable design and ensures the repair effect.

[0064] The dimensions of the components in this embodiment are preferably as follows:

[0065] The outer diameter of the central tube 2 is 63mm-139.7mm and the length is 2000mm-5000mm; 8 internal pressure holes 5 are distributed at equal intervals in the middle of the central tube (90° in the circumferential direction and 30mm-50mm between the two holes in the longitudinal direction), and the diameter of the internal pressure hole 5 is 3mm-10mm; the outer diameter of the upper rubber tube 4 and the lower rubber tube 9 is 80mm-200mm and the length is 200mm-800mm; the outer diameter of the outer tube movement mechanism 3 is 73mm-150mm and the length matches the central tube 2; the outer diameter of the airbag 6 is 80mm-200mm and the length is 300mm-900mm; the capsule string is a hollow elliptical cylinder with a length of 15mm-30mm and a diameter of 5mm-10mm, into which the repair fluid can be injected, and the capsules can be connected in series as needed to form capsule strings of different lengths. The specific dimensions of each component of the tool are appropriately matched according to the size of the downhole pipe string to be repaired.

[0066] Example 5

[0067] On the basis of the above embodiments, in this embodiment, the plurality of repair liquid A capsule strings 7 respectively include a plurality of repair liquid A capsules, and the plurality of repair liquid B capsule strings 14 respectively include a plurality of repair liquid B capsules.

[0068] The capsule string includes a plurality of capsules containing different repair liquids, so as to facilitate uniform mixing of different repair liquids.

[0069] In addition, the plurality of repair liquid A capsule strings 7 and the plurality of repair liquid B capsule strings 14 are both formed by connecting a plurality of capsules end to end in sequence (eg, by gluing or integrally forming) to form a long string structure.

[0070] Example 6

[0071] On the basis of the above embodiments, in this embodiment, the two groups of internal pressure hole groups respectively include a plurality of internal pressure holes 5, and the plurality of internal pressure holes 5 in each group are evenly spaced on the central tube 2; the two groups of external pressure hole groups respectively include a plurality of external pressure holes 8, and the plurality of external pressure holes 8 in each group are evenly spaced on the corresponding outer tube movement mechanism 3, which are consistent in number and corresponding in position to the plurality of internal pressure holes 5 in the corresponding group.

[0072] Multiple internal pressure holes 5 and multiple external pressure holes 8 are evenly distributed, so that the pressure change in the central tube 2 can be used to expand the airbag 6 to squeeze the capsule string group on the airbag 6. The capsule string group ruptures to allow the repair fluid inside to flow out for pipe string repair, which is convenient for repair.

[0073] The multiple internal pressure holes 5 in each group can be evenly divided into multiple small groups, the multiple small groups are evenly spaced along the circumference of the central tube 2 , and the multiple internal pressure holes 5 in each small group are evenly spaced along the axial direction of the central tube 2 .

[0074] Example 7

[0075] On the basis of the above embodiments, in this embodiment, two annular grooves are spaced apart on the central tube 2, the two outer tube movement mechanisms 3 are movably installed in the two annular grooves, and the two internal pressure hole groups are distributed in the two annular grooves, respectively.

[0076] The structural design of the central tube 2 is reasonable, and it is convenient to install the two outer tube movement mechanisms.

[0077] Based on the above solution, when the multiple internal pressure holes 5 are connected to the multiple external pressure holes 8 respectively, the two ends of the two outer tube movement mechanisms 3 are respectively in contact with the ends of the two annular grooves on the central tube 2 that are close to each other.

[0078] Example 8

[0079] On the basis of the above embodiments, in this embodiment, the two sealing members are respectively annular rubber cylinders, the airbag 6 is an annular airbag, and the outer diameters of the two annular rubber cylinders are greater than the outer diameter of the annular airbag.

[0080] The shapes of the airbag 6 and the two rubber tubes are reasonably designed, which is convenient for assembly on the central tube 2, expansion of the rubber tube to fit the inner wall of the pipe column, and expansion of the airbag 6 to squeeze the capsule string group for repair work.

[0081] Based on the above solution, the two sealing members are respectively an upper rubber cylinder 4 and a lower rubber cylinder 9 .

[0082] Preferably, in this embodiment, the inner sides of the outer ends of the two seals (the side that is in close contact with the leakage pipe column and faces the annular airbag) are designed to be in an arc shape so that an arc space is generated after the leakage pipe column is tightened.

[0083] After the airbag is inflated, it avoids the formation of sharp corners on the inner side of the leaking pipe column and the seal to cause the accumulation of repair fluid, thereby improving the utilization efficiency of the repair fluid.

[0084] Example 9

[0085] On the basis of the above embodiments, in this embodiment, both ends of the central tube 2 are respectively connected with joints.

[0086] The two joints are reasonably designed to facilitate the connection of the workover string and the positioner.

[0087] Based on the above solution, the joint connected to the upper end of the central tube 2 is the upper joint 1 , and the joint connected to the lower end of the central tube 2 is the lower joint 10 .

[0088] Example 10

[0089] On the basis of the above embodiments, this embodiment further provides a method for in-situ repairing a downhole tubular joint leakage, which is implemented by using the in-situ repairing tool for downhole tubular joint leakage as described above, and includes the following specific steps:

[0090] S1: The upper end of the central pipe 2 is connected to the well repair string, and the lower end is connected to the positioner, and is lowered into the micro gap 13 of the leaking pipe string 11 to be repaired, and the lower end of the central pipe 2 is sealed at the same time;

[0091] S2: injecting fluid into the central tube 2 to move the two outer tube movement mechanisms 3 to the point where the two groups of outer pressure holes thereon are respectively connected to the two groups of inner pressure holes on the central tube 2, and at the same time, the two outer tube movement mechanisms 3 squeeze the two seals to make the two seals closely attached to the inner wall of the leakage column 11, so that an annular closed space is formed between the leakage column joint 12 of the leakage column 11 and the central tube 2 and the two seals;

[0092] S3: Continue to inject fluid into the central tube 2 to expand the airbag 6 and squeeze the capsule string group thereon, so that the capsule string group ruptures and the repair fluid inside flows out and mixes in the annular closed space;

[0093] S4: Continue to inject fluid into the central tube 2 , and the mixed repair fluid forms a protective film at the micro gap 13 under the squeezing of the airbag 6 .

[0094] This embodiment also provides a repair method, which can effectively solve the problem of casing annulus pressure caused by micro-leakage of the pipe column joint. The on-site operation is convenient, does not affect the pipe column diameter and subsequent operations, and greatly saves costs.

[0095] The working principle of the present invention is as follows:

[0096] (1) The upper joint 1 of the central tube 2 is connected to the workover string, and the lower joint 10 of the central tube 2 is connected to the magnetic positioning logging instrument, so as to facilitate the lowering of the repair tool to the known leakage position and achieve accurate repair;

[0097] (2) Throwing a ball to the lower joint 10 of the repair tool or pre-installing a blind plate at the lower joint 10 of the repair tool in advance to block the pipe string and block the upper and lower fluids;

[0098] (3) Pressurize the inside of the repair tool by 3 MPa to 5 MPa, and the outer tube movement mechanism 3 moves to squeeze the lower rubber tube 9, so that the rubber tube is fastened to the lower part of the inner wall of the joint of the leaking pipe string 11 and is sealed;

[0099] (4) Continue to pressurize the repair string by 6MP to 8MPa, and the outer tube movement mechanism 3 moves to squeeze the upper rubber tube 4, so that the rubber tube is fastened to the upper part of the inner wall of the joint of the leaking string 11 and is sealed;

[0100] (5) An annular closed space is now formed between the leaking pipe column joint 12 and the repair tool;

[0101] (6) Continue to pressurize the repair string to 9MPa-10MPa, and the outer tube movement mechanism moves 3 to connect the outer pressure hole 8 with the inner pressure hole 5;

[0102] (7) Continue to pressurize the repair string at 11MPa to 13MPa, and the airbag 6 swells. Due to the guidance of the arc shape of the rubber tube, the airbag 6 gradually approaches the inner wall of the leaking pipe column joint 12. Under the gradual squeezing of the airbag 6, the capsule string group ruptures, and the internal repair fluid flows out and mixes;

[0103] (8) Continue to pressurize the repair string to 14 MPa to 16 MPa, and maintain the pressure for 5 to 30 minutes. The repair liquid penetrates into the micro gap 13 of the leaking joint under the continuous squeezing of the airbag 6, and forms a protective film on the inner wall surface of the leaking joint;

[0104] (9) Gradually release the pressure, remove the underground repair tools, promptly remove the broken capsule string, and clean the repair tools.

[0105] The present invention aims at the problem of annular pressure caused by micro-leakage of completion pipe joints, and proposes an in-situ repair tool and repair method for a fixed pipe string. The repair tool is lowered to the leakage point to perform fixed-point repair on the joint micro-leakage, and then the repair tool is pulled out to restore the pipe string diameter without affecting subsequent production operations.

[0106] The downhole tubular joint leakage in-situ repair tool and downhole repair method invented by the present invention can effectively solve the problem of casing annulus pressure caused by micro-leakage of tubular joints, facilitate on-site operations, do not affect the tubular diameter and subsequent operations, and greatly save various expenses incurred by replacing tubulars.

[0107] The present invention is applicable to the management of the annular space pressure of oil casing in various complex gas wells. Currently, a large amount of investment is being made in the construction of various complex gas wells, and the construction of a well costs tens of millions of yuan or even hundreds of millions of yuan. However, the existing gas wells are basically all produced with annular space pressure, which brings certain safety risks. The solution provided by the present invention can further solve the annular space pressure problem caused by tubing leakage, provide technical means for annular space pressure management, restore the sealing integrity of the wellbore, and effectively extend the service life of oil and gas wells. Therefore, the present invention will produce good economic benefits and has broad application prospects.

[0108] It should be noted that all electronic components involved in the present invention adopt the existing technology, and the above-mentioned components are electrically connected to the controller, and the control circuit between the controller and each component is the existing technology.

[0109] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0110] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

[0111] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A downhole pipe string joint leakage in-situ repair tool, characterized by: The invention comprises a central tube (2), an air bag (6), two flexible sealing members and two outer tube movement mechanisms (3), wherein the central tube (2) is arranged vertically and two groups of internal pressure hole groups are arranged thereon at intervals; the two outer tube movement mechanisms (3) are respectively coaxially sleeved on the central tube (2), and are respectively provided with external pressure hole groups thereon, and can be moved to the two groups of external pressure hole groups to be connected with or staggered with the two groups of internal pressure hole groups respectively; the air bag (6) is fixedly sleeved outside the opposite ends of the two outer tube movement mechanisms (3), and a capsule string group containing repair fluid is installed thereon; the two sealing members are fixedly sleeved outside the central tube (2), and are respectively located outside the two outer tube movement mechanisms (3); the air bag (6) is located between the two sealing members, and is respectively located outside the two groups of external pressure hole groups and the two groups of internal pressure hole groups.

2. The downhole pipe string joint leakage in-situ repair tool according to claim 1, characterized in that: The capsule string group comprises a plurality of repair liquid A capsule strings (7) and a plurality of repair liquid B capsule strings (14), and the plurality of repair liquid A capsule strings (7) and the plurality of repair liquid B capsule strings (14) are evenly spaced and distributed on the airbag (6).

3. The downhole pipe string joint leakage in-situ repair tool according to claim 2, characterized in that: The plurality of repair liquid A capsule strings (7) and the plurality of repair liquid B capsule strings (14) are respectively arranged in a plurality of rows along the axial direction of the airbag (6); the plurality of rows of repair liquid A capsule strings (7) and the plurality of rows of repair liquid B capsule strings (14) are alternately arranged in sequence at even intervals along the circumference of the airbag (6).

4. The downhole pipe string joint leakage in-situ repair tool according to claim 2, characterized in that: The plurality of repair liquid A capsule strings (7) and the plurality of repair liquid B capsule strings (14) are distributed on the airbag (6) in a spiral shape, and the plurality of repair liquid A capsule strings (7) and the plurality of repair liquid B capsule strings (14) are arranged alternately in sequence.

5. The downhole pipe string joint leakage in-situ repair tool according to claim 3 or 4, characterized in that: The plurality of repair liquid A capsule strings (7) respectively include a plurality of repair liquid A capsules, and the plurality of repair liquid B capsule strings (14) respectively include a plurality of repair liquid B capsules.

6. The downhole pipe string joint leakage in-situ repair tool according to any one of claims 1 to 4, characterized in that: The two groups of internal pressure hole groups respectively include a plurality of internal pressure holes (5), and the plurality of internal pressure holes (5) in each group are evenly spaced and distributed on the central tube (2); the two groups of external pressure hole groups respectively include a plurality of external pressure holes (8), and the plurality of external pressure holes (8) in each group are evenly spaced and distributed on the corresponding outer tube movement mechanism (3), and the number and position of the plurality of internal pressure holes (5) in the corresponding group are consistent.

7. The downhole pipe string joint leakage in-situ repair tool according to any one of claims 1 to 4, characterized in that: Two annular grooves are arranged at intervals on the central tube (2), the two outer tube movement mechanisms (3) are movably installed in the two annular grooves respectively, and the two internal pressure hole groups are distributed in the two annular grooves respectively.

8. The downhole pipe string joint leakage in-situ repair tool according to any one of claims 1 to 4, characterized in that: The two sealing members are respectively annular rubber cylinders, the airbag (6) is an annular airbag, and the outer diameters of the two annular rubber cylinders are greater than the outer diameter of the annular airbag.

9. The downhole pipe string joint leakage in-situ repair tool according to any one of claims 1 to 4, characterized in that: Both ends of the central tube (2) are respectively connected with joints.

10. A method for in-situ repair of downhole pipe string joint leakage, characterized in that: The method is implemented by using the downhole pipe string joint leakage in-situ repair tool as claimed in any one of claims 1 to 9, comprising the following specific steps: S1: The upper end of the central pipe (2) is connected to the well repairing pipe string, and the lower end is connected to the positioner, and is lowered into the micro gap (13) of the leaking pipe string (11) to be repaired, and the lower end of the central pipe (2) is sealed at the same time; S2: injecting fluid into the central tube (2) to move the two outer tube movement mechanisms (3) to the point where the two groups of outer pressure holes on the central tube (2) are respectively connected to the two groups of inner pressure holes on the central tube (2); at the same time, the two outer tube movement mechanisms (3) squeeze the two seals so that the two seals are in close contact with the inner wall of the leakage pipe column (11), so that an annular closed space is formed between the leakage pipe column joint (12) of the leakage pipe column (11), the central tube (2) and the two seals; S3: Continue to inject fluid into the central tube (2) to expand the airbag (6) and squeeze the capsule string group thereon, so that the capsule string group ruptures and the repair fluid inside flows out and mixes in the annular closed space; S4: Continue to inject fluid into the central tube (2), and the mixed repair fluid forms a protective film at the micro gap (13) under the squeezing of the air bag (6).

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