A downhole tubular string joint leak in situ repair tool and method

Abstract

The application relates to a downhole pipe string joint leakage in-situ repairing tool and a repairing method, which comprises a center pipe, an air bag, two flexible sealing members and two outer pipe movement mechanisms, the center pipe is vertically arranged, two groups of inner pressure hole groups are arranged on the center pipe at intervals, the two outer pipe movement mechanisms are coaxially sleeved on the center pipe, outer pressure hole groups are arranged on the two outer pipe movement mechanisms, the air bag is fixedly sleeved on the opposite ends of the two outer pipe movement mechanisms, a capsule string group filled with repairing liquid is arranged on the air bag, the two sealing members are fixedly sleeved outside the center pipe and are located outside the two outer pipe movement mechanisms, the air bag is located between the two sealing members, and the two groups of outer pressure hole groups and the two groups of inner pressure hole groups are located outside the air bag. The application has the beneficial effect that the oil casing annulus pressure problem caused by the micro-leakage of the pipe string joint can be effectively solved, the on-site operation is convenient, the pipe string drift diameter and the subsequent operation are not affected, and the cost is greatly saved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oil production engineering, in particular to a downhole pipe string joint leakage in-situ repair tool and repair method. BACKGROUND

[0002] The existing deep well, ultra-deep well and gas storage well have frequent opening and closing, strong injection and strong production, and high temperature and high pressure working conditions. The completion pipe string is composed of safety valve, tubing string, packer and other components, and has many risk points, which leads to frequent gas well A annulus pressure. For example, the highest annulus pressure of the gas storage well A is greater than or equal to 5MPa, accounting for 61.5%, mainly because the threaded joint of the gas storage injection and production pipe string is prone to sealing failure under alternating load, which leads to the annulus pressure of the gas storage well casing, and the first well barrier is completely lost, which makes the production have extremely high safety risk. In order to restore the first well barrier, the best way is to carry out pipe string replacement work, but the engineering operation cost is too high, and the well killing operation is easy to cause reservoir pollution, resulting in production decline. Therefore, a chemical plugging glue appears in the market, which is currently mainly used for plugging the formation after casing perforation, and restoring the sealing integrity of the casing cement sheath. The annulus injection and plugging of the chemical plugging glue only has application cases in low pressure environment of heavy oil thermal recovery well in Shengli Oilfield, and forms a hundreds of meters long annular column in the oil casing annulus after plugging. The column is harder than the cement sheath. The applicability of annulus injection and plugging of the chemical plugging glue in the high pressure dynamic load environment of deep well, ultra-deep well and gas storage well is not clear, and after the oil casing is plugged, it will cause complex pipe string lifting and well repair in the later period.

[0003] The completion pipe string uses a gas seal threaded structure, and the leakage of the gas seal threaded joint often appears at the leakage point. The leakage occurs when the pressure is higher than the leakage point pressure, and no leakage occurs when the pressure is lower than the leakage point pressure. Therefore, the leakage of the completion pipe string joint is mostly micro-permeation, and the cost of replacing the pipe string is high. However, controlling the leakage point pressure will reduce the injection and production operating pressure, and the production efficiency will be greatly reduced.

[0004] The main problems existing in the prior art are: 1) the cost of replacing the pipe string for well repair is high and easy to cause reservoir pollution; 2) the existing chemical plugging glue has large dosage and high cost in annulus injection and plugging, and is easy to cause complex difficulty in pipe string lifting and well repair in the later period. Therefore, the present application provides a downhole in-situ repair tool and repair technology method, which greatly saves the cost, realizes the downhole in-situ repair, and ensures the pipe string passage diameter, without affecting the subsequent production operation. SUMMARY

[0005] The technical problem to be solved by the present application is to provide a downhole pipe string joint leakage in-situ repair tool and repair method, aiming at solving the problems in the prior art.

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

[0007] The application discloses a downhole tubular string joint leakage in-situ repairing tool, which comprises a center pipe, a gas bag, two flexible sealing members and two outer pipe moving mechanisms, the center pipe is vertically arranged and is provided with two groups of inner pressure holes at intervals, the two outer pipe moving mechanisms are coaxially arranged on the center pipe and are respectively provided with outer pressure hole groups, and the outer pipe moving mechanisms are respectively movable to the two groups of outer pressure hole groups to be communicated with or staggered with the two groups of inner pressure hole groups, the gas bag is fixedly arranged on the opposite ends of the two outer pipe moving mechanisms and is provided with a capsule string group containing repairing liquid, and the two sealing members are fixedly arranged outside the center pipe and are respectively located outside the two outer pipe moving mechanisms, the gas bag is located between the two sealing members and is located outside the two groups of outer pressure hole groups and the two groups of inner pressure hole groups.

[0008] The application has the beneficial effects that, during the repairing process, firstly, the upper end of the center pipe is connected with a well repairing tubular string, the lower end is connected with a positioner, and is lowered into a micro gap of a leakage tubular string to be repaired, and the lower end of the center pipe is sealed; secondly, fluid is injected into the center pipe to move the two outer pipe moving mechanisms to be communicated with the two groups of outer pressure hole groups on the center pipe, and the two outer pipe moving mechanisms extrude the two sealing members to make the two sealing members closely adhere to the inner wall of the leakage tubular string, so that an annular closed space is formed between the leakage tubular string joint sleeved on the leakage tubular string, the center pipe and the two sealing members; thirdly, the fluid is continuously injected into the center pipe to make the gas bag swell and extrude the capsule string group on the gas bag, the capsule string group is broken, the internal repairing liquid flows out and is mixed in the annular closed space; and finally, the fluid is continuously injected into the center pipe, the mixed repairing liquid forms a protective film at the micro gap under the extrusion of the gas bag, the repairing efficiency is high, and the service life of the oil and gas well is prolonged.

[0009] The application can effectively solve the problem of casing annulus pressure caused by the micro leakage of the tubular string joint, is convenient for field operation, does not affect the tubular string diameter and subsequent operation, and greatly saves the cost.

[0010] On the basis of the above technical scheme, the application can be further improved as follows.

[0011] Further, the capsule string group comprises a plurality of repairing liquid A capsule strings and a plurality of repairing liquid B capsule strings, and the plurality of repairing liquid A capsule strings and the plurality of repairing liquid B capsule strings are uniformly and intervally distributed on the gas bag.

[0012] The beneficial effects of the above further scheme are that the plurality of repairing liquid A capsule strings and the plurality of repairing liquid B capsule strings are intervally distributed on the gas bag, so that the internal repairing liquid can be uniformly mixed, and the repairing quality is ensured.

[0013] Further, the plurality of said repair liquid A capsule strings and the plurality of said repair liquid B capsule strings are arranged in multiple rows along the axial direction of the air bag, and the multiple rows of said repair liquid A capsule strings and the multiple rows of said repair liquid B capsule strings are alternately arranged in sequence and uniformly spaced along the circumferential direction of the air bag.

[0014] The beneficial effect of the above further scheme is that the plurality of repair liquid A capsule strings and the plurality of repair liquid B capsule strings are reasonably distributed on the air bag, which can further mix the repair liquid inside evenly to ensure the quality of repair.

[0015] Further, the plurality of said repair liquid A capsule strings and the plurality of said repair liquid B capsule strings are spirally distributed on the air bag, and the plurality of said repair liquid A capsule strings and the plurality of said repair liquid B capsule strings are alternately arranged in sequence.

[0016] The beneficial effect of the above further scheme is that the plurality of repair liquid A capsule strings and the plurality of repair liquid B capsule strings are reasonably distributed on the air bag, which can further mix the repair liquid inside evenly to ensure the quality of repair.

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

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

[0019] Further, the two groups of said inner pressure hole groups respectively comprise a plurality of inner pressure holes, and the plurality of said inner pressure holes in each group are uniformly spaced on the center pipe; the two groups of said outer pressure hole groups respectively comprise a plurality of outer pressure holes, and the plurality of said outer pressure holes in each group are uniformly spaced on the corresponding outer pipe movement mechanism, and the number and position of the plurality of said inner pressure holes in the corresponding group are consistent.

[0020] The beneficial effect of the above further scheme is that the plurality of inner pressure holes and the plurality of outer pressure holes are uniformly distributed, which facilitates the expansion of the air bag by the pressure change in the center pipe to extrude the capsule string group on the air bag, and the repair liquid inside the broken capsule string group flows out to repair the pipe column, which is convenient for repair.

[0021] Further, the center pipe is provided with two annular grooves at intervals, and the two outer pipe movement mechanisms are movably installed in the two annular grooves, and the two groups of said inner pressure holes are respectively distributed in the two annular grooves.

[0022] The beneficial effect of the above further scheme is that the structure of the center pipe is reasonably designed, which facilitates the installation of the two outer pipe movement mechanisms.

[0023] Further, the two sealing members are annular rubber rings, the air bag is an annular air bag, and the outer diameters of the two annular rubber rings are greater than the outer diameter of the annular air bag.

[0024] The beneficial effect of the further scheme is that the shapes of the air bag and the two rubber rings are reasonable, which facilitates assembly on the central pipe, facilitates the expansion of the rubber rings and the adhesion of the inner wall of the pipe string, and facilitates the expansion of the air bag to extrude the capsule string, so as to facilitate the repair operation.

[0025] Further, the two ends of the central pipe are respectively connected with joints.

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

[0027] The present application also relates to a downhole pipe string joint leakage in-situ repair method, which is realized by using the downhole pipe string joint leakage in-situ repair tool as described above, and comprises the following specific steps:

[0028] S1: the upper end of the central pipe is connected with a workover pipe string, the lower end of the central pipe is connected with a positioner, and the central pipe is lowered into a micro gap of a leakage pipe string to be repaired, and the lower end of the central pipe is sealed;

[0029] S2: fluid is injected into the central pipe to move the two outer pipe movement mechanisms to the two groups of outer pressure hole groups to be in communication with the two groups of inner pressure hole groups on the central pipe, and the two sealing members are extruded by the two outer pipe movement mechanisms to be tightly attached to the inner wall of the leakage pipe string, so that the leakage pipe string joint outside the leakage pipe string forms an annular airtight space with the central pipe and the two sealing members;

[0030] S3: the fluid is continuously injected into the central pipe to extrude the capsule string group on the air bag, the capsule string group is broken, the internal repair liquid flows out and mixes in the annular airtight space;

[0031] S4: the mixed repair liquid forms a protective film at the micro gap under the extrusion of the air bag by continuously injecting the fluid into the central pipe.

[0032] The beneficial effect of the further scheme is that the present application also provides a repair method, which can effectively solve the problem of casing annulus pressure caused by the micro leakage of the pipe string joint, the field operation is convenient, the pipe string drift diameter and subsequent operation are not affected, and the cost is greatly saved. BRIEF DESCRIPTION OF DRAWINGS

[0033] Fig. 1 It is a schematic diagram of the overall structure of the repair tool in the present application;

[0034] Fig. 2 It is a schematic diagram of the overall structure of the repair tool in the present application;

[0035] Fig. 3 Figure 1 is a schematic diagram of a first distribution scheme of capsule strings in the present application.

[0036] Fig. 4 Figure 2 is a schematic diagram of a second distribution scheme of capsule strings in the present application.

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

[0038] 1, upper joint; 2, central tube; 3, outer tube movement mechanism; 4, upper rubber sleeve; 5, inner pressure hole; 6, air bag; 7, repair liquid A capsule string; 8, outer pressure hole; 9, lower rubber sleeve; 10, lower joint; 11, leak-off string; 12, leak-off string joint; 13, micro gap; 14, repair liquid B capsule string. DETAILED DESCRIPTION

[0039] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0040] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element indicated must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second" and the like are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features limited by "first", "second" and the like can explicitly or implicitly include one or more of the features. In the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0041] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

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

[0043] Embodiment 1

[0044] As Figs. 1 to 4 The embodiment provides a downhole pipe string joint leakage in-situ repair tool which comprises a center pipe 2, an air bag 6, two flexible sealing members and two outer pipe movement mechanisms 3, the center pipe 2 is vertically arranged, two groups of inner pressure holes are arranged on the center pipe 2 at intervals, the two outer pipe movement mechanisms 3 are coaxially arranged on the center pipe 2 respectively, outer pressure hole groups are arranged on the two outer pipe movement mechanisms 3 respectively, and the two outer pipe movement mechanisms 3 can be moved to the two groups of outer pressure holes to be communicated with or staggered with the two groups of inner pressure holes respectively, the air bag 6 is fixedly arranged on the opposite ends of the two outer pipe movement mechanisms 3, and a capsule string group containing a repair liquid is arranged on the air bag 6, and the two sealing members are fixedly arranged outside the center pipe 2 and located outside the two outer pipe movement mechanisms 3 respectively, the air bag 6 is located between the two sealing members and outside the two groups of outer pressure holes and the two groups of inner pressure holes.

[0045] During the repair process, first, the upper end of the center pipe 2 is connected with a workover pipe string, the lower end is connected with a positioner (the positioner is preferably a magnetic positioning logging instrument in the prior art), and the center pipe 2 is lowered to the micro gap 13 of the leakage pipe string 11 to be repaired, and the lower end of the center pipe 2 is sealed; second, fluid is injected into the center pipe 2 to move the two outer pipe movement mechanisms 3 to the two groups of outer pressure holes to be communicated with the two groups of inner pressure holes on the center pipe 2, and the two outer pipe movement mechanisms 3 extrude the two sealing members to make the two sealing members tightly adhere to the inner wall of the leakage pipe string 11, so that the leakage pipe string joint 12 sleeved on the leakage pipe string 11 forms an annular closed space with the center pipe 2 and the two sealing members; then, the fluid is continuously injected into the center pipe 2 to make the air bag 6 expand and extrude the capsule string group on the air bag 6, the capsule string group is broken, the repair liquid in the capsule string group flows out and mixes in the annular closed space; finally, the fluid is continuously injected into the center pipe 2, and the mixed repair liquid forms a protective film at the micro gap 13 under the extrusion of the air bag 6, the repair efficiency is high, and the service life of the oil and gas well is prolonged.

[0046] Based on the above scheme, the two groups of outer pressure holes need to be communicated with or staggered with the two groups of inner pressure holes at the same time, when communicated, the two outer pipe movement mechanisms 3 can extrude the two sealing members, so that the two sealing members, the center pipe 2 and the leakage pipe string 11 form an annular closed space, so as to facilitate the subsequent repair operation.

[0047] Preferably, in the embodiment, the center pipe 2 is preferably a circular pipe structure, and the two ends of the center pipe 2 are both open.

[0048] Preferably, in the embodiment, the air bag 6 is preferably a rubber air bag.

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

[0050] In addition, the specific structure and matching relationship of the two outer pipe movement mechanisms 3 and the two sealing members are both prior art, and the specific structure is disclosed in a Chinese patent with publication number CN207315296U, a double rubber cylinder packer.

[0051] The setting principles of the upper and lower sealing members are the same as those of the double rubber cylinder packer on the market, that is, 1) a certain internal pressure (fluid injection) is applied to the central pipe 2, the lower outer pipe movement mechanism 3 is first moved to extrude the lower flexible sealing member, and the sealing member is tightly set on the lower part of the inner wall of the leaking pipe string 11 joint; 2) continue to press the central pipe, the upper outer pipe movement mechanism 3 moves to extrude the upper flexible sealing member, and the sealing member is tightly set on the upper part of the inner wall of the leaking pipe string 11 joint, so that an annular closed space is formed between the leaking pipe string 11, the upper and lower sealing members, and the repair tool, and the repair tool is set.

[0052] If the central pipe 2 is continuously pressed, the outer pipe movement mechanism 3 will further move to connect the outer pressure hole 8 and the central pipe internal pressure hole 5; the air bag 6 is inflated by continuously pressing the central pipe 2, and the circular arc shape of the sealing member guide makes the air bag 6 gradually approach the inner wall of the leaking pipe string joint 12, the capsule string is broken under the gradual extrusion of the air bag, and the internal repair liquid flows out and mixes. The embodiment can effectively solve the problem of oil-casing annulus pressure caused by micro-leakage of the pipe string joint, the on-site operation is convenient, the pipe string diameter and subsequent operation are not affected, and the cost is greatly saved.

[0053] Embodiment 2

[0054] On the basis of embodiment 1, in the embodiment, the capsule string group includes a plurality of repair liquid A capsule strings 7 (such as organic silicon modified epoxy resin) and a plurality of repair liquid B capsule strings 14 (such as aromatic amine), and the plurality of repair liquid A capsule strings 7 and the plurality of repair liquid B capsule strings 14 are uniformly and interval distributed on the air bag 6.

[0055] The plurality of repair liquid A capsule strings 7 and the plurality of repair liquid B capsule strings 14 are interval distributed on the air bag 6, which can make the internal repair liquid mix uniformly and ensure the quality of repair.

[0056] Embodiment 3

[0057] On the basis of embodiment 2, in the embodiment, the plurality of repair liquid A capsule strings 7 and the plurality of repair liquid B capsule strings 14 are arranged into multiple rows along the axial direction of the air bag 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 and uniformly and interval along the circumferential direction of the air bag 6.

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

[0059] Embodiment 4

[0060] In the embodiment, the multiple repair liquid A capsule strings 7 and the multiple repair liquid B capsule strings 14 are spirally distributed on the air bag 6, and the multiple repair liquid A capsule strings 7 and the multiple 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 air bag 6, which can further make the repair liquid inside mixed uniformly and ensure the quality of repair.

[0062] The above-mentioned embodiment 3 and embodiment 4 are parallel schemes.

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

[0064] The sizes of the components in the 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 inner pressure holes 5 are distributed at equal intervals in the central tube (90° in the circumferential direction, 30mm-50mm apart between two holes in the longitudinal direction), and the diameter of the inner pressure hole 5 is 3mm-10mm; the outer diameter of the upper rubber cylinder 4 and the lower rubber cylinder 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 air bag 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, which can inject repair liquid, and the capsules can be connected together to form a capsule string of different lengths as needed. The specific sizes of the components of the tool are matched according to the size of the downhole pipe string to be repaired.

[0066] Embodiment 5

[0067] In the embodiment, the multiple repair liquid A capsule strings 7 each include multiple repair liquid A capsules, and the multiple repair liquid B capsule strings 14 each include multiple repair liquid B capsules.

[0068] The capsule string contains multiple capsules containing different repair liquids, which facilitates 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 each formed by sequentially connecting (e.g., by adhesive or by integral molding) a plurality of capsules end to end.

[0070] Embodiment 6

[0071] On the basis of the above embodiments, in the present embodiment, the two groups of inner pressure holes each include a plurality of inner pressure holes 5, which are uniformly spaced on the central pipe 2; the two groups of outer pressure holes each include a plurality of outer pressure holes 8, which are uniformly spaced on the corresponding outer pipe movement mechanism 3, and the number and positions of the plurality of outer pressure holes 8 in each group correspond to those of the plurality of inner pressure holes 5 in the corresponding group.

[0072] The uniform distribution of the plurality of inner pressure holes 5 and the plurality of outer pressure holes 8 facilitates the use of pressure changes in the central pipe 2 to cause the air bag 6 to expand to squeeze the capsule string group on the air bag 6, and the rupture of the capsule string group to cause the repair liquid inside to flow out to repair the pipe column.

[0073] The plurality of inner pressure holes 5 in each group can be divided into a plurality of subgroups, which are uniformly spaced along the circumference of the central pipe 2, and the plurality of inner pressure holes 5 in each subgroup are uniformly spaced along the axis of the central pipe 2.

[0074] Embodiment 7

[0075] On the basis of the above embodiments, in the present embodiment, the central pipe 2 is provided with two annular grooves, the two outer pipe movement mechanisms 3 are movably installed in the two annular grooves, and the two groups of inner pressure holes are distributed in the two annular grooves.

[0076] The central pipe 2 is designed reasonably in structure, facilitating the installation of the two outer pipe movement mechanisms.

[0077] Based on the above scheme, when the plurality of inner pressure holes 5 and the plurality of outer pressure holes 8 are in communication, the two ends of the two outer pipe movement mechanisms 3 are in abutment with the end of the two annular grooves on the central pipe 2 that are close to each other at this time.

[0078] Embodiment 8

[0079] On the basis of the above embodiments, in the present embodiment, the two sealing members are each an annular rubber tube, the air bag 6 is an annular air bag, and the outer diameter of the two annular rubber tubes is greater than the outer diameter of the annular air bag.

[0080] The air bag 6 and the two rubber tubes are designed reasonably in shape, facilitating the assembly on the central pipe 2, the inflation of the rubber tubes to adhere to the inner wall of the pipe column, and the inflation of the air bag 6 to squeeze the capsule string group, so as to facilitate the repair operation.

[0081] Based on the above scheme, the two sealing members are the upper rubber sleeve 4 and the lower rubber sleeve 9.

[0082] Preferably, in the embodiment, the inner side of the outer end of the two sealing members (the side close to the annular air bag after being tightly attached to the leaking pipe column) is designed in a circular arc shape, so that an arc space is formed after the leaking pipe column is fastened.

[0083] After the air bag is inflated, a sharp corner space is avoided to be formed on the inner side of the contact between the leaking pipe column and the sealing member, so that the repair fluid is accumulated, and the utilization efficiency of the repair fluid is improved.

[0084] Embodiment 9

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

[0086] The two joints are reasonably designed, and the well repair pipe column and the positioner are conveniently connected.

[0087] Based on the above scheme, the joint connected with the upper end of the central pipe 2 is the upper joint 1, and the joint connected with the lower end of the central pipe 2 is the lower joint 10.

[0088] Embodiment 10

[0089] On the basis of the above embodiments, the embodiment further provides a well downhole pipe column joint leakage in-situ repair method, which is realized by using the well downhole pipe column joint leakage in-situ repair tool as described above, and includes the following specific steps.

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

[0091] S2: Fluid is injected into the central pipe 2 to make the two outer pipe movement mechanisms 3 move to the two groups of outer pressure holes respectively communicate with the two groups of inner pressure holes on the central pipe 2, while the two outer pipe movement mechanisms 3 extrude the two sealing members to make the two sealing members tightly attached to the inner wall of the leaking pipe column 11, so that the leaking pipe column joint 12 of the leaking pipe column 11 forms an annular sealed space with the central pipe 2 and the two sealing members;

[0092] S3: The fluid is continuously injected into the central pipe 2 to make the air bag 6 swell and extrude the capsule string group on it, the capsule string group is broken, and the internal repair fluid flows out and mixes in the annular sealed space;

[0093] S4: The mixed repair fluid forms a protective film at the micro gap 13 under the extrusion of the air bag 6 by continuously injecting the fluid into the central pipe 2.

[0094] The embodiment also provides a repairing method, which can effectively solve the problem of annular pressure caused by micro-leakage of a pipe string joint, is convenient for field operation, does not affect the pipe string drift diameter and subsequent operation, and greatly saves cost.

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

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

[0097] (2) The ball is thrown to the lower joint 10 of the repairing tool or a blind plate is pre-installed at the lower joint 10 of the repairing tool, so as to block the pipe string and block the fluid;

[0098] (3) 3MPa-5MPa is pressed into the repairing tool, the outer pipe movement mechanism 3 moves to extrude the lower rubber cylinder 9, so that the rubber cylinder is tightly fixed and set on the lower inner wall of the leakage pipe string 11 joint;

[0099] (4) 6MP-8MPa is continuously pressed into the repairing pipe string, the outer pipe movement mechanism 3 moves to extrude the upper rubber cylinder 4, so that the rubber cylinder is tightly fixed and set on the upper inner wall of the leakage pipe string 11 joint;

[0100] (5) Now the annular sealing space is formed between the leakage pipe string joint 12 and the repairing tool;

[0101] (6) 9MPa-10MPa is continuously pressed into the repairing pipe string, the outer pipe movement mechanism 3 moves to make the outer pressure hole 8 communicate with the inner pressure hole 5;

[0102] (7) 11MPa-13MPa is continuously pressed into the repairing pipe string, the air bag 6 is inflated, the air bag 6 gradually approaches the inner wall of the leakage pipe string joint 12 due to the guidance of the circular arc shape of the rubber cylinder, the lower rubber cylinder string group is gradually extruded and broken under the extrusion of the air bag 6, and the internal repairing liquid flows out and mixes;

[0103] (8) 14MPa-16MPa is continuously pressed into the repairing pipe string, and the pressure is stabilized for 5-30 minutes, the repairing liquid deeply enters the micro gap 13 of the leakage joint under the continuous extrusion of the air bag 6, and a protective film is formed on the inner wall surface of the leakage joint;

[0104] (9) Gradually depressurize, lift the downhole repairing tool, and timely remove the broken rubber cylinder string group and clean the repairing tool.

[0105] The present application is aimed at the problem of annular pressure caused by micro-leakage of a well completion pipe string joint, and proposes a downhole in-situ repairing tool and repairing method without moving the pipe string, the repairing tool is lowered to the leakage position, the joint micro-leakage is repaired at the fixed point, then the repairing tool is lifted, the pipe string drift diameter is restored, and the subsequent production operation is not affected.

[0106] The downhole pipe string joint leakage in-situ repair tool and downhole repair method provided by the present application can effectively solve the problem of casing annulus pressure caused by pipe string joint micro-leakage, is convenient for field operation, does not affect the pipe string drift diameter and subsequent operation, and greatly saves various costs caused by pipe string lifting and replacement.

[0107] The present application is suitable for casing annulus pressure management in various complex gas wells. At present, various complex gas wells are being vigorously invested and constructed, and the construction of a well is in the hundreds of millions of yuan, even in the hundreds of millions of yuan. However, the existing gas wells are basically produced with annulus pressure, which brings certain safety risks, and the scheme provided by the present application can further solve the problem of annulus pressure caused by pipe string leakage, provide a technical means for annulus pressure management, restore the sealing integrity of the wellbore, and effectively prolong the service life of the oil and gas well. Therefore, the present application will produce good economic benefits and has a wide application prospect.

[0108] It should be noted that each electronic component involved in the present application uses existing technology, and each of the above components is electrically connected to the controller. The control circuit between the controller and each component is prior art.

[0109] For those skilled in the art, it is obvious that the present application is not limited to the details of the above exemplary embodiments, and the present application can be realized in other specific forms without departing from the spirit or essential characteristics of the present application. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting, and the scope of the present application is defined by the appended claims rather than the above description, and therefore all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present application. Any reference signs in the claims should not be considered as limiting the claims involved.

[0110] In addition, it should be understood that although the present specification is described in terms of embodiments, not every embodiment contains only one independent technical solution, and the description manner of the specification is only for the sake of clarity, and those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be properly combined to form other embodiments that those skilled in the art can understand.

[0111] The above is only the preferred embodiment of the present application, and is not intended to limit the present application, and any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A tool for in-situ repair of leaks in downhole tubing joints, characterized in that: The device includes a central tube (2), an airbag (6), two flexible seals, and two outer tube movement mechanisms (3). The central tube (2) is vertically arranged and has two sets of internal pressure holes spaced apart on it. The two outer tube movement mechanisms (3) are coaxially sleeved on the central tube (2) and have external pressure holes on them respectively. They are movable so that the two sets of external pressure holes are connected to or offset from the two sets of internal pressure holes respectively. The airbag (6) is fixedly sleeved on the opposite ends of the two outer tube movement mechanisms (3) and has a capsule string containing repair fluid installed on it. The two seals are fixedly sleeved on the outside of the central tube (2) and are located outside the two outer tube movement mechanisms (3) respectively. The airbag (6) is located between the two seals and is located outside the two sets of external pressure holes and the two sets of internal pressure holes respectively.

2. The in-situ repair tool for leaks in downhole tubing joints according to claim 1, characterized in that: The capsule string group includes multiple repair fluid A capsule strings (7) and multiple repair fluid B capsule strings (14), which are evenly spaced on the airbag (6).

3. The in-situ repair tool for leaks in downhole tubing joints according to claim 2, characterized in that: Multiple strings of repair fluid A capsules (7) and multiple strings of repair fluid B capsules (14) are arranged in multiple rows extending along the axial direction of the airbag (6). The multiple rows of repair fluid A capsules (7) and multiple rows of repair fluid B capsules (14) are arranged alternately and at uniform intervals along the circumference of the airbag (6).

4. The in-situ repair tool for leaks in downhole tubing joints according to claim 2, characterized in that: Multiple strings of repair fluid A capsules (7) and multiple strings of repair fluid B capsules (14) are spirally distributed on the airbag (6), and the multiple strings of repair fluid A capsules (7) and multiple strings of repair fluid B capsules (14) are arranged alternately in sequence.

5. The in-situ repair tool for leaks in downhole tubing joints according to claim 3 or 4, characterized in that: The plurality of repair fluid A capsule strings (7) each include a plurality of repair fluid A capsules, and the plurality of repair fluid B capsule strings (14) each include a plurality of repair fluid B capsules.

6. The in-situ repair tool for leaks in downhole tubing joints according to any one of claims 1-4, characterized in that: The two sets of internal pressure holes each include multiple internal pressure holes (5), and the multiple internal pressure holes (5) in each set are evenly spaced on the central tube (2); the two sets of external pressure holes each include multiple external pressure holes (8), and the multiple external pressure holes (8) in each set are evenly spaced on the corresponding external tube moving mechanism (3), and their numbers and positions are consistent with the multiple internal pressure holes (5) in the corresponding set.

7. The in-situ repair tool for leaks in downhole tubing joints according to any one of claims 1-4, characterized in that: The central tube (2) is provided with two annular grooves at intervals. The two outer tube moving mechanisms (3) are respectively movably installed in the two annular grooves, and the two inner pressure hole groups are respectively distributed in the two annular grooves.

8. The in-situ repair tool for leaks in downhole tubing joints according to any one of claims 1-4, characterized in that: The two sealing elements are annular rubber cylinders, the airbag (6) is annular airbag, and the outer diameter of the two annular rubber cylinders is larger than the outer diameter of the annular airbag.

9. The in-situ repair tool for leaks in downhole tubing joints according to any one of claims 1-4, characterized in that: The two ends of the central tube (2) are respectively connected to connectors.

10. A method for in-situ repair of leaks in downhole tubing joints, characterized in that: The in-situ repair tool for leaks in downhole tubing joints as described in any one of claims 1-9 is used, and includes the following specific steps: S1: The upper end of the central tube (2) is connected to the well repair string, the lower end is connected to the locator, and it is lowered into the micro gap (13) of the leaking string (11) to be repaired, while sealing the lower end of the central tube (2). S2: Inject fluid into the central tube (2) to move the two outer tube movement mechanisms (3) to the two sets of external pressure holes on them to communicate with the two sets of internal pressure holes on the central tube (2) respectively. At the same time, the two outer tube movement mechanisms (3) squeeze the two seals to make the two seals fit tightly against the inner wall of the leakage column (11), so that the leakage column joint (12) of the leakage column (11) forms an annular sealed space between the central tube (2) and the two seals. S3: Continue to inject fluid into the central tube (2) to inflate the airbag (6) and squeeze the capsule string on it. The capsule string ruptures and the internal repair fluid flows out and mixes in the annular sealed 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 compression of the airbag (6).

Images