A sealing patching tool

Abstract

A kind of sealing patching tool, it includes patching pipe assembly, expanding assembly and flow distributor, the patching pipe assembly includes patching pipe and sealing hanger, the patching pipe is matched with casing damage well casing specification Steel pipe, length is 8m-12m, both ends are all turned to sealing thread capable of being connected with sealing hanger;The sealing hanger is composed of hanger pipe, rubber sealing ring, metal sealing ring, the hanger pipe is a section of reducing steel pipe, the diameter of one end with sealing thread is same with the diameter of patching pipe, the diameter of one end with rubber sealing ring and metal sealing ring is installed is less than the diameter of patching pipe, two sets of sealing hangers are provided in each set of tool, are installed in the both ends of patching pipe by sealing thread respectively, the utility model sealing pressure is high, hanging is reliable, patching pipe does not produce flexure, patching section drift diameter is big, secondary extraction is easy.

Description

Technical Field

[0001] This utility model relates to the field of oil and gas field production technology, specifically a sealing and patching tool. Background Technology

[0002] As oilfield development continues, downhole casing breaks or is damaged for various reasons, causing injection and production tools to malfunction or become unusable. This not only affects the normal development of oil and gas fields but also pollutes formation water and the surface environment, making it a major problem that must be solved in oilfield development.

[0003] Solutions to casing damage include chemical plugging, casing replacement, and casing patching. Chemical plugging is only suitable for wells with minor casing corrosion and perforation; casing replacement is costly and limited by well depth; casing patching is the most widely used method because it is more adaptable than chemical plugging, less costly than casing replacement, and not limited by well depth.

[0004] Existing casing patching technologies include three types: non-sealed support patching, two-end expansion sealing patching, and fully expansion sealing patching.

[0005] The non-sealed support method involves inserting a section of steel pipe (hereinafter referred to as the support pipe) into the area where the casing has fractured and the fracture site has become misaligned (hereinafter referred to as misalignment). The support pipe serves to straighten and reinforce the casing. Because this method lacks a sealing function, it is only suitable for wells where the damaged area is not in the oil and gas production zone and where there is no serious leakage at the misalignment site. Since wells meeting both of these conditions are rare, its applicability is relatively limited.

[0006] The double-expansion sealing and patching method involves installing a soft metal (copper, aluminum, lead, etc.) ring (approximately 20mm wide) on the outer side of each end of the patch tube, and a high-hardness conical ring on the inner side of each end. High pressure is generated by a high-pressure pump or by igniting explosives to push the high-hardness conical rings into the patch tube, causing it to expand. The expanded patch tube presses the soft metal rings against the inner wall of the casing. The soft metal rings serve both a sealing and suspension function for the patch tube. However, because the conical rings at both ends of the patch tube are subjected to opposing forces simultaneously, the patch tube expands under compression, resulting in flexible deformation. This deformation persists after patching, causing the actual diameter of the patched section to be smaller than the theoretical diameter. This prevents some injection and production tools from reaching their operating depth due to outer diameter limitations. For example, in an oilfield, a Ø140mm casing using the double-expansion sealing and patching method has a theoretical patch diameter of Ø108mm, but even a Ø105mm well gauge cannot pass through. Secondly, this type of seal, which relies on the "fitting" of soft metal with the casing, has low pressure resistance, especially when there are corrosion pits or scale on the inner wall of the casing. Slight leakage occurs initially after patching, and over time, this slight leakage develops into a larger leak, gradually weakening the sealing performance and suspension capacity until it completely fails. During later construction work, incomplete shrinkage of the packer sleeve below the patch tube often results in the patch tube being "carried out" by the lifting string.

[0007] The fully expandable sealing and patching method involves installing several rubber rings on the outer sides of both ends of the patch tube. Once the patch tube is lowered to the designed location, a high-pressure pump is used to push a specialized expansion tool, fully expanding the patch tube. The expanded patch tube presses the rubber rings against the inner wall of the sleeve, where the rubber rings simultaneously provide a seal and suspension. This patching method offers reliable sealing and suspension, and allows for a relatively large patch diameter. However, its drawbacks include difficulty in removing the patch tube, increasing construction costs.

[0008] Of the aforementioned two or three types of subsidies, for non-sealed support subsidies, removing the subsidy tube simply requires lowering a specialized retrieval tool, catching it, and then lifting it to release the seal. For double-expansion sealed subsidies, removing the subsidy tube requires lowering a specialized milling tool to grind away the upper expansion section of the subsidy tube (generally no more than 0.3m in length), then lowering the specialized retrieval tool to catch it and lift it out. For fully expansion sealed subsidies, removing the subsidy tube requires lowering a specialized milling tool to mill away the entire subsidy tube. Because the subsidy tube is entirely attached to the inner wall of the casing, and the section requiring milling is relatively long, the selection of milling tools and the control of milling parameters are subject to strict requirements. Any error can easily damage the casing or even cause an accident.

[0009] The reason for removing the subsidy pipe is that this situation frequently occurs: some wells experience new casing damage after subsidy is applied, and about 50% of the new casing damage points are below the original damage points. To apply subsidy to the new damage points, the subsidy pipe for the original damage point must first be removed. Because the outer diameter of the subsidy tool is larger than the inner diameter of the original subsidy section, it cannot be lowered. After applying subsidy to the new damage points, the original damage points are then re-subsidized. Therefore, removing the subsidy pipe is an unavoidable procedure in major workover operations; otherwise, the damaged well cannot be repaired.

[0010] In view of the current state of the technology, the present invention provides a new sealing and patching process to overcome the shortcomings of the above patching methods. Utility Model Content

[0011] In view of the above situation and to overcome the defects of the prior art, this utility model provides a sealing and patching tool, which effectively solves the problems mentioned in the background art.

[0012] To achieve the above objectives, this utility model provides the following technical solution: This utility model includes a subsidy pipe assembly, an expansion assembly, and a flow distributor.

[0013] The subsidy pipe assembly includes a subsidy pipe and a sealing suspension body. The subsidy pipe is a steel pipe that matches the specifications of the casing of the damaged well, with a length of 8m-12m, and both ends are machined with sealing threads that can connect to the sealing suspension body. The sealing suspension body consists of a suspension pipe, a rubber sealing ring, and a metal sealing ring. The suspension pipe is a section of steel pipe with different diameters. The diameter of the end with the sealing thread is the same as the diameter of the subsidy pipe, and the diameter of the end with the rubber sealing ring and the metal sealing ring is smaller than the diameter of the subsidy pipe. Each tool set is equipped with two sets of sealing suspension bodies, which are installed at both ends of the subsidy pipe through sealing threads.

[0014] The expansion assembly includes an expansion cone, a central tube, a central rod, a transition connecting tube, and a flow distributor. The expansion cone is conical in shape, with a conical surface a at one end for expanding the tube, and grooves on both the inner and outer sides of the other end for installing the first sealing ring. Each set of sealing and patching tools is equipped with one expansion cone. The two cones are identical in shape and size and are installed opposite each other at the large diameter of the sealing suspension body at both ends of the patch tube assembly. The central tube and the central rod pass through the inner holes of the upper and lower expansion cones, respectively, and are then connected into a whole by the threads on the transition connecting tube, the flow distributor, and the limiting ring. The function of the expansion assembly is to carry the patch tube assembly down into the well and expand the diameter of both ends of the patch tube assembly downhole to achieve the purpose of sealing and suspension. After the sealing and suspension actions are achieved, the expansion assembly can be retrieved from the well.

[0015] The flow distributor consists of components such as a connector, upper connecting pipe, upper valve, upper valve seat, pressure regulating spring, rubber sleeve, rubber sleeve seat, rubber sleeve center tube, lower center tube, ball head assembly, support spring, lower valve seat, lower valve, adjusting ring, and second sealing ring. Its function is to automatically control the flow rate of the liquid driving the expansion cone to move, ensuring that both the upper and lower expansion cones can operate in place. Before going down into the well, the spring force of the pressure regulating spring is adjusted through the connector and adjusting ring to set the opening pressure of the upper and lower valves between 0.5MPa and 0.8MPa.

[0016] The flow distributor has a ball head assembly and two support springs at its center. The upper and lower ball heads of the ball head assembly, together with the center holes of the upper and lower valve seats, respectively, form the upper annular channel T1 and the lower annular channel T2. The two support springs prevent the upper and lower ball heads from contacting the sealing surfaces of the valve seats when there is liquid flow in both the upper and lower annular channels T1 and T2, ensuring unobstructed flow. When the high-pressure pump pressurizes, the liquid enters the flow distributor through the central tube, enters the central channel T through the main inlet, and then splits into two paths: one path flows through the upper annular channel T1 and the outlet, pushing open the upper valve. After leaving the upper valve seat, some pressure is lost and the liquid enters the sealed space formed by the expansion assembly and the auxiliary tube assembly, pushing the upper expansion cone upward. The other liquid flows through the lower annular channel T and the lower outlet hole, pushing the lower valve away from the lower valve seat. After losing some pressure, the liquid enters the sealed space formed by the expansion assembly and the auxiliary tube assembly, pushing the lower expansion cone downward. The flow rates of the two liquids are the same. At the same time as the two liquids flow out of the valve and the valve seat, a pressure drop of 0.5MPa-0.8MPa is generated due to the action of the pressure regulating spring. The pressure difference between the inside and outside causes the rubber sleeve to expand and stick to the inner wall of the auxiliary tube.

[0017] The flow rate at which the ball head assembly begins to move is set to 3-4 times the normal flow rate of the upper annular channel T1 and the lower annular channel T2. When a certain expanding cone reaches its position, the liquid pressure drops. If the upper expanding cone reaches its position first, all the liquid will flow out through the upper annular channel T1. When its flow rate reaches the designed value for the ball head assembly to begin moving, the ball head assembly moves upward, causing the ball head sealing surface to contact the ball seat sealing surface. The liquid flow in the upper annular channel T1 is blocked. At this time, the liquid can only enter the closed space formed by the expanding assembly and the auxiliary tube assembly through the lower annular channel T2, the lower outlet hole, and the lower valve. As the pressure rises, the rubber sleeve expands to stop the liquid flow. When the pressure rises to a certain value at the leak port of the already expanded upper sealing suspension, the lower expanding cone continues to expand the sealing suspension until it is fully expanded. When the lower sealing suspension is fully expanded, the liquid flows into the wellbore through the lower sealing suspension, the system pressure drops, and all the liquid will flow out through the lower annular channel T2. When its flow rate reaches the designed value for the ball head assembly to start moving, the ball head assembly moves downward, and the upper annular channel T1 is reopened. At this time, because both the upper and lower ends of the auxiliary pipe assembly are connected to the wellbore, the ball head assembly returns to its original position under the action of the support spring, and the tubing can no longer generate pressure, indicating that the auxiliary pipe assembly has been attached to the well casing.

[0018] Beneficial effects: This utility model has high sealing and pressure resistance, reliable suspension, no bending of the patch tube, large diameter of the patch section, and easy secondary removal. Attached Figure Description

[0019] The accompanying drawings are provided to further illustrate the present invention and form part of the specification. They are used together with the embodiments of the present invention to explain the present invention, but do not constitute a limitation thereof. In the drawings:

[0020] Figure 1 This is a schematic diagram of the tubular column structure of this utility model;

[0021] Figure 2 This is a schematic diagram of the flow distributor structure of this utility model;

[0022] Figure 3 This is a utility model Figure 2 Enlarged view of the cross-section at point AA;

[0023] Figure 4 This is a utility model Figure 2 Enlarged view of the cross-section at point BB;

[0024] Figure 5 This is a schematic diagram showing the change in the shape of the sealing support column after the upper sealing suspension body of this utility model expands.

[0025] Figure 6 This is a schematic diagram showing the change in shape of the flow distributor after the upper sealing suspension body of this utility model expands.

[0026] Figure 7a This is a schematic diagram of the first structure of the flow distributor of this utility model;

[0027] Figure 7b This is a schematic diagram of the second structure of the flow distributor of this utility model;

[0028] Figure 7c This is a schematic diagram of the third structure of the flow distributor of this utility model;

[0029] Figure 8a This is a schematic diagram of the first structure of the sealing and patching tool assembly of this utility model;

[0030] Figure 8b This is a schematic diagram of the second structure of the sealing and patching tool assembly of this utility model;

[0031] Figure 8c This is a schematic diagram of the third structure of the sealing and patching tool assembly of this utility model;

[0032] Figure 9a This is a schematic diagram of the first structure of the present invention for retrieving the subsidy pipe from the well.

[0033] Figure 9b This is a schematic diagram of the second structure for retrieving the subsidy pipe from the well according to this utility model;

[0034] Figure 9c This is a schematic diagram of the third structure of the utility model for retrieving the subsidy pipe from the well.

[0035] Figure 10 This is a utility model Figure 6 A magnified structural diagram of A in the middle;

[0036] The diagram labels are as follows: 100, Subsidy pipe assembly; 101, Subsidy pipe; 200, Sealing suspension body; 201, Suspension pipe; 201a, Expanded diameter surface; 202, Rubber sealing ring; 203, Metal sealing ring; 300, Expanded diameter assembly; 301, Central pipe; 302, Expanded diameter cone; 302a, Conical surface; 303, Transition connecting pipe; 304, Central rod; 305, Limiting ring; 306, First sealing ring; 400, Flow distributor; 401, Connector; 402, Upper connecting pipe; 403, Upper valve; 404, Upper valve seat; 404a, Main inlet; 404b, Upper outlet; 404c, Ball seat sealing surface; 405, Pressure regulating spring; 406, Rubber sleeve; 407, Rubber sleeve seat; T, Central channel; T1, Upper annular channel; T2, Lower annular channel; 408, Rubber sleeve central pipe; 409. Lower center tube; 409a. Lower outlet hole; 410. Ball head assembly; 410a. Ball head sealing surface; 411. Support spring; 412. Lower valve seat; 413. Lower valve; 414. Adjusting ring; 415. Second sealing ring; 500. Well casing; 501. Milling and grinding workover tools; 502. Fishing and retrieval workover tools; 600. Marking line. Detailed Implementation

[0037] The following is in conjunction with the appendix Figure 1-10 The specific embodiments of this utility model will be described in further detail.

[0038] Example 1, by Figure 1-10 The present invention provides a sealing and patching tool, which consists of four parts: patching tube, sealing suspension body, expansion accessory, and flow distributor.

[0039] The supplementary pipe 101 is a steel pipe that matches the specifications of the casing of the damaged well, typically 8m-12m in length. Both ends are machined with sealing threads for connection to the sealing suspension body 200. The sealing suspension body 200 consists of the suspension pipe 201, a rubber sealing ring 202, and a metal sealing ring 203. The suspension pipe 201 is a section of steel pipe with a different diameter; the end with the sealing threads has the same diameter as the supplementary pipe 101, while the end with the rubber sealing ring 202 and metal sealing ring 203 has a smaller diameter than the supplementary pipe 101. This smaller end will eventually be expanded downhole to match the inner diameter of the larger end. Each tool kit includes two sealing suspension bodies 200, installed at both ends of the supplementary pipe 101 via sealing threads. The assembly of the supplementary pipe 101 and the sealing suspension body 200 is called the supplementary pipe assembly 100.

[0040] Reference Figure 1 Figure 2The expansion assembly 300 consists of the expansion accessories and the flow distributor 400. The expansion cone 302 is a major component of the expansion assembly 300. The expansion cone 302 is conical, with a conical surface 301a for expanding the pipe at one end, and grooves for installing the first sealing ring 306 on both the inner and outer sides of the other end. Each sealing and patching tool is equipped with two expansion cones 302, which are identical in shape and size and are installed opposite each other (in opposite directions) at the large diameter of the sealing suspension bodies 200 at both ends of the patch pipe assembly 100. The central tube 301 and the central rod 304 pass through the inner holes of the upper and lower expansion cones 302, respectively, and are then connected into a whole by threads on the transition connecting pipe 303, the flow distributor 400, and the limiting ring 305. In the sealing and patching process, the function of the expansion assembly 300 is to carry the patch pipe assembly 100 downhole and expand the diameter of both ends of the patch pipe assembly 100 downhole to achieve the purpose of sealing and suspension. After the sealing and suspension actions are completed, the enlarged diameter assembly 300 needs to be pulled out of the well.

[0041] Reference Figures 1-4 The flow distributor 400 is another major component of the expansion assembly 300. Its function is to automatically control the flow rate of the liquid driving the expansion cone 302, ensuring that both the upper and lower expansion cones 302 are in position. The flow distributor 400 consists of a connector 401, an upper connecting pipe 402, an upper valve 403, an upper valve seat 404, a pressure regulating spring 405, a rubber sleeve 406, a rubber sleeve seat 407, a rubber sleeve center tube 408, a lower center tube 409, a ball head assembly 410, a support spring 411, a lower valve seat 412, a lower valve 413, an adjusting ring 414, and a second sealing ring 415. The relative positions and connections of these components will be detailed in the tool and ground assembly operation method.

[0042] The ground assembly operation method of the sealing and patching tool of the present invention:

[0043] A. Ground assembly method for flow distributor

[0044] Reference Figure 7a

[0045] 1-1, 1-2: Connect the internal thread of the large diameter end of connector 401 to the upper connecting pipe 402;

[0046] 1-3, 1-4: Sequentially place the pressure adjusting spring 405 and the upper valve 403 with the second sealing ring 415 pre-installed on the outside of the upper connecting pipe 402;

[0047] 1-5: Connect the upper valve seat 404 to the lower part of the upper connecting pipe 402;

[0048] 1-6: Connect the center tube 408 of the rubber sleeve to the lower part of the upper valve seat 404;

[0049] 1-7: Fit the support springs 411 onto the outside of the ball head 410, one on each side. Then place them inside the upper valve seat 404;

[0050] 1-8: Connect the lower center tube 409 to the bottom of the rubber sleeve center tube 408;

[0051] Reference Figure 7b

[0052] 1-9, 1-10, 1-11: Connect the upper end of the rubber sleeve 406 to the rubber sleeve seat 407 and the lower end to the lower valve seat 412. Then, fit this connected assembly onto the outside of the rubber sleeve center tube 408 and the lower center tube 409, and connect the thread of the lower valve seat 412 to the thread of the lower center tube 409.

[0053] Reference Figure 7c

[0054] 1-12, 1-13: Sequentially place the lower valve 413, which has the second sealing ring 415 pre-installed, and the pressure adjusting spring 405 on the outside of the lower central tube 409;

[0055] 1-14: Connect the adjusting ring 414 to the outside of the lower central tube 409 via thread. The flow distributor is now assembled on the ground. Before lowering it into the well, adjust the spring force of the pressure regulating spring through the connector 401 and the adjusting ring 414 to set the opening pressure of the upper and lower valves between 0.5MPa and 0.8MPa.

[0056] B. Ground assembly method for sealing and patching tools

[0057] Reference Figure 8a Assemble the expanded diameter assembly

[0058] 2-1, 2-2: Pass the central tube 301 through the expanded diameter cone 302 pre-installed with the first sealing ring 306, with the cone surface 302a facing the central tube coupling;

[0059] 2-3, 2-4: Connect the transition connecting pipe 303 below the central pipe 301, and then connect the flow distributor 400 below the transition connecting pipe 303;

[0060] 2-5: Connect the center rod 304 to the bottom of the flow distributor 400;

[0061] 2-6, 2-7: Place the expanded diameter cone 302, which has the first sealing ring 306 pre-installed, on the outside of the center rod 304, with the cone surface 302a facing the direction of the installation limit ring 305, and then install the limit ring 305.

[0062] Reference Figure 8b Assemble the upper sealed suspension body and the auxiliary pipe.

[0063] 2-8: With the threaded end of the sealing suspension body 200 facing downwards, slide it over the center tube 301 and onto the outside of the expanded diameter assembly 300;

[0064] 2-9: Insert the subsidy tube 101 upwards from the side of the center rod and connect it to the sealing suspension body 200 through threads;

[0065] Reference Figure 8c Assemble the lower sealed suspension body

[0066] 2-10: With the threaded end of the sealing suspension body 200 facing upwards, slide it under the center rod 304 and connect it to the auxiliary tube 101 through the thread. Then adjust the distance between the upper surface of the limiting ring 305 and the bottom surface of the sealing suspension body 200 to make it 10mm to 20mm greater than the length of the expanding cone 302.

[0067] At this point, the sealing and patching tool has been fully assembled on the ground.

[0068] Working principle of the sealing and patching tool of this invention:

[0069] Reference Figures 1-6 Subsidized columns, such as Figure 1 As shown. When the tubing is lowered to the designed depth in the well, a high-pressure pump is used on the surface to pressurize the liquid (water or mud, etc.) inside the tubing. The liquid pressure acts simultaneously on the bottom surfaces of the upper and lower expansion cones 302, causing the cone surface 302a of the expansion cone 302 to expand the expansion surface 201a of the suspension pipe 201. Finally, the upper and lower expansion cones 302 completely expand the small diameter portion of their respective sealing suspension bodies 200, so that the rubber sealing ring 202 and the metal sealing ring 203 are tightly pressed between the suspension pipe 201 and the inner wall of the well casing, achieving the effect of sealing and suspension.

[0070] As can be seen from the above working principle, the upper and lower expanding cones 302 are in the same pressure system and move in opposite directions. The advantage of this reverse movement is that it allows the auxiliary tube 101 to be suspended under tension, completely avoiding the deflection phenomenon caused by the auxiliary tube 101 being subjected to opposing forces in existing auxiliary technologies. The reverse movement of the upper and lower expanding cones 302 means that each expanding cone 302 corresponds to a set of expanded components, including one suspension tube 201, two rubber sealing rings 202, and one metal sealing ring 203, which expand in opposite directions. Although each expanding cone 302 and each set of expanded parts are made of the same material, shape and size, due to the influence of many unknown and uncontrollable factors such as the microscopic differences in the material and size of the parts and the slight differences in the inner diameter and shape of the sleeve at the sealing suspension, the upper and lower expanding cones 302 cannot be in position at the same time (referring to the position of the expanding cone 302 when the small diameter part of the sealing suspension 200 is fully expanded). When either one is in position, the liquid pressure will drop immediately because that end loses its seal. At this time, the expanding cone 302 that has not been in position will stop moving due to the loss of driving force, so that the subsidy cannot be completed in the end.

[0071] To address the issue of pressure system loss caused by the upper and lower expanding cones not reaching their positions simultaneously, a flow distributor 400 was designed. (Refer to...) Figure 2 - Figure 4The flow distributor 400 has a ball head assembly 410 and two support springs 411 at its center. The upper and lower ball heads of the ball head assembly 410, together with the center holes of the upper valve seat 404 and the lower valve seat 412, respectively, form the upper annular channel T1 and the lower annular channel T2. Because the ball head assembly 410 has a built-in centering wing, the two ball heads are always centered in the flow distributor 400. The two support springs 411 prevent the upper and lower ball heads from contacting the sealing surfaces of the ball seats when there is liquid flow in both the upper annular channel T1 and the lower annular channel T2, ensuring unobstructed flow. When the high-pressure pump pressurizes, liquid enters the flow distributor 400 through the central pipe 301 and enters the central channel T through the main inlet port 404a. The flow then splits into two paths: one path flows through the upper annular channel T1 and the outlet hole 404b, pushing open the upper valve 403 and leaving the upper valve seat 404. After losing some pressure, it enters the sealed space formed by the expansion assembly 300 and the auxiliary pipe assembly 100, pushing the upper expansion cone 302 upward. Simultaneously, the other path flows through the lower annular channel T2 and the lower outlet hole 409a, pushing open the lower valve 413 and leaving the lower valve seat 412. After losing some pressure, it enters the sealed space formed by the expansion assembly 300 and the auxiliary pipe assembly 100, pushing the lower expansion cone 302 downward. Because the upper and lower expansion cones 302 and the upper and lower sealing suspension bodies 200 are exactly the same size in the entire device, the movement speed of the two expansion cones will be basically the same under the same pressure, so the flow rates of the two paths are basically the same. As the two liquids flow out from the valve and valve seat, a pressure drop of 0.5MPa-0.8MPa is generated due to the action of the pressure regulating spring. The internal and external pressure difference causes the rubber sleeve 406 to expand and adhere to the inner wall of the auxiliary tube 101. When the pressure rises to a certain value, the upper and lower expanding cones 302 begin to expand their respective sealing suspension bodies 200.

[0072] In fluid mechanics, the study and analysis of flow around a cylinder in a water pipe shows that when water flows around a cylinder, it forms a complex vortex structure. These vortices interact with the surface of the cylinder, generating lift and drag. As the flow velocity increases, the lift and drag also increase. When these forces are sufficient to overcome the static friction of the cylinder, the cylinder begins to move. In this invention, the ball joint assembly 410 is equivalent to the cylinder in the water pipe. By controlling the flow velocity of the liquid flowing over its surface, its stationary or moving state can be controlled. In application, the normal flow rates of the upper annular channel T1 and the lower annular channel T2 can be calculated based on the dimensions of the auxiliary pipe assembly 100 and the designed operating speed of the expansion cone 302. By changing the cross-sectional areas of the annular channel T1 and the lower annular channel T2, combined with experiments such as adjusting the elastic force of the support spring 411, a suitable threshold for the ball joint assembly 410 to begin moving can be determined. In this invention, the flow rate at which the ball joint assembly 410 begins to move is set to 3 to 4 times the normal flow rates of the upper annular channel T1 and the lower annular channel T2.

[0073] Reference Figure 5 , Figure 6 This further explains the working principle of the flow distributor 400. During construction, when a certain expansion cone 302 reaches its position, it is assumed here that the upper expansion cone 302 reaches its position first (e.g., Figure 5 At this point, due to the large influx of liquid into the wellbore from the already expanded upper sealing suspension 200, the system pressure immediately drops, and the expanding cone 302 stops moving due to loss of propulsion. This cessation of movement inevitably results in no liquid flowing through the lower annular channel T2. At this time, all the liquid will flow out through the upper annular channel T1. When its flow rate reaches the designed value for the ball head assembly 410 to begin moving, the ball head assembly 410 moves upward, causing the ball head sealing surface 410a to contact the ball seat sealing surface 404c (as shown). Figure 6 (Enlarged at point A) The fluid flow in the upper annular channel T1 is blocked. At this time, the fluid has only one path: through the lower annular channel T2 and the lower outlet hole 409a, it pushes open the lower valve 413 and enters the sealed space formed by the expansion assembly 300 and the auxiliary pipe assembly 100. Although the upper sealing suspension 200 has expanded, creating a fluid leak, as the pressure rises, the rubber sleeve 406 expands and adheres to the inner wall of the auxiliary pipe 101, preventing the fluid from flowing to the leak. When the pressure rises to a certain value, the lower expansion cone 302 continues to expand the sealing suspension 200 until it is fully expanded. When the lower sealing suspension 200 is fully expanded, a large amount of fluid flows into the wellbore through the lower sealing suspension 200, and the system pressure drops accordingly. At this time, all the fluid will flow out through the lower annular channel T2. When its flow rate reaches the designed value for the ball head assembly 410 to start moving, the ball head assembly 410 moves downward, and the closed upper annular channel T1 is reopened. At this point, since both ends of the auxiliary pipe assembly 100 are connected to the wellbore, the fluid will simultaneously flow into the wellbore through the upper annular channel T1 and the lower annular channel T2. The fluid flow velocity in both directions of the ball head assembly 410 is the same, and the forces exerted by the fluid on it are opposite in direction, resulting in a net force of zero. It returns to its original position under the action of the support spring. At this point, no more pressure can be generated in the tubing string, indicating that the auxiliary pipe assembly 100 has been successfully attached to the well casing. The tubing string is then deployed, bringing out the enlarged diameter assembly 300 and all accessories including the flow distributor 400, completing the installation.

[0074] The above-mentioned operation of running the subsidized tubing into the well will be further explained in the application examples.

[0075] Application Examples:

[0076] The present invention will be further illustrated below through two embodiments:

[0077] Example 1: Downhole Subsidy Construction Operation Method

[0078] Downhole subsidy tubing, such as Figure 1As shown. Before running the casing into the well, the length of the replacement pipe should be determined based on the length of the damaged casing, and it should generally be 4m longer than the length of the damaged casing. If the length of the damaged casing is too long and the length of the replacement pipe cannot meet the 4m requirement, the length can be reduced to 2m.

[0079] During operation, the auxiliary tool is connected below the delivery string (drill pipe or tubing). After reaching the designed depth, water or mud, or other kill fluid, is injected into the string from the surface. The injected fluid must be free of impurities, not produce solid sediment, and expel any gas from the string.

[0080] Pressurize the tubing using a high-pressure pump on the ground, ensuring a steady pressure rise. During pressurization, carefully observe pressure changes. When the pressure reaches the value required for the expansion cone 302 to expand the sealing suspension 200, it will fluctuate within a small range and then stop rising. This indicates that the expansion cone 302 is expanding the sealing suspension 200. If the pressure suddenly drops sharply and then rises steadily, it means one expansion cone 302 has reached its operating position. If the pressure drops sharply again, until it reaches zero and cannot rise further, it means the other expansion cone 302 has also reached its operating position, and the expansion process is complete.

[0081] The delivery string was retrieved, and the condition of all components of the 300mm diameter expansion assembly was inspected to initially assess the construction effectiveness. Subsequent pressure testing, well cleaning, and depth calibration were used to qualitatively evaluate the construction results.

[0082] Example 2: Method for removing the downhole patch cord

[0083] Before construction, confirm the well casing data, auxiliary pipe specifications, and suspension pipe dimensions.

[0084] The first step is to mill the upper sealing suspension body 200 (refer to...). Figure 9a )

[0085] Based on the dimensions of the well casing, auxiliary pipe, and suspension pipe, select appropriate milling tools and lower them to the top of the upper sealing suspension body 200. Using suitable drilling pressure and rotation speed, [the tool is then]... Figure 9a The portion of the sealed suspension body circled by the 600 mark is milled off by grinding.

[0086] The second step involves retrieving the subsidy pipe and the lower sealing suspension body 200 (refer to...). Figure 9b )

[0087] Based on the dimensions of the well casing, patch tubing, and suspension tubing, select appropriate retrieval tools, lower them into the patch tubing, and slowly pull them out after securing them. If the load is heavy, move the tubing up and down slowly until the load returns to normal, then retrieve the retrieval string. Carefully inspect the retrieved patch tubing for any damage left downhole.

[0088] If the well is stuck and cannot be pulled up, exceeding the safe load of the well workover equipment, and multiple measures have failed, a reverse-threading method can be used to disconnect the connection between the auxiliary pipe and the sealing suspension 200. First, retrieve the auxiliary pipe, then lower a suitable milling tool to grind away the lower sealing suspension 200. Figure 9c As shown. This operation of the present invention is not available in existing two-end expansion sealing and patching technologies, providing a safe and efficient method for removing the patch tube.

[0089] Finally, it should be noted that the above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A sealing and patching tool, characterized in that, It includes a subsidy pipe assembly (100), an expansion assembly (300), and a flow distributor (400). The subsidy pipe assembly (100) includes a subsidy pipe (101) and a sealing suspension body (200). The subsidy pipe (101) is a steel pipe that matches the specifications of the casing of the damaged well. The length is 8m-12m, and both ends are machined with sealing threads that can be connected to the sealing suspension body (200). The sealing suspension body (200) consists of a suspension pipe (201), a rubber sealing ring (202), and a metal sealing ring (203). The suspension pipe (201) is a section of steel pipe with different diameters. The diameter of the end with the sealing thread is the same as the diameter of the subsidy pipe (101), and the diameter of the end with the rubber sealing ring (202) and the metal sealing ring (203) is smaller than the diameter of the subsidy pipe (101). Each tool set is equipped with two sets of sealing suspension bodies (200), which are installed at both ends of the subsidy pipe (101) through sealing threads.

2. The sealing patch tool according to claim 1, characterized in that: The expansion assembly (300) includes an expansion cone (302), a central tube (301), a central rod (304), a transition connecting tube (303), and a flow distributor (400). The expansion cone (302) is conical in shape, with a conical surface (301a) for expanding the tube at one end and grooves for installing the first sealing ring (306) on both the inner and outer sides of the other end. Each set of sealing and patching tools is equipped with two expansion cones (302), which are identical in shape and size and are installed opposite each other at the large diameter of the sealing suspension bodies (200) at both ends of the patching tube assembly (100). The central tube (301) and the central rod (304) pass through the inner holes of the upper and lower expansion cones (302) respectively, and then these expansion accessories are connected into a whole through the threads on the transition connecting pipe (303), the flow distributor (400) and the limiting ring (305). The function of the expansion assembly (300) is to carry the auxiliary pipe assembly (100) down into the well, and to expand the diameter of both ends of the auxiliary pipe assembly (100) down into the well to achieve the purpose of sealing and suspension. After the sealing and suspension action is achieved, the expansion assembly (300) can be taken out from the well.

3. A sealing patch tool according to claim 2, characterized in that: The flow distributor (400) consists of a connector (401), an upper connecting pipe (402), an upper valve (403), an upper valve seat (404), a pressure regulating spring (405), a rubber sleeve (406), a rubber sleeve seat (407), a rubber sleeve center pipe (408), a lower center pipe (409), a ball head assembly (410), a support spring (411), a lower valve seat (412), a lower valve (413), an adjusting ring (414), and a second sealing ring (415). Its function is to automatically control the flow rate of the liquid driving the expansion cone (302) to ensure that both the upper and lower expansion cones (302) can operate in place. Before going down into the well, the spring force of the pressure regulating spring is adjusted through the connector (401) and the adjusting ring (414) to set the opening pressure of the upper and lower valves between 0.5MPa and 0.8MPa.

4. A sealing patch tool according to claim 3, characterized in that: The flow distributor (400) has a ball head assembly (410) and two support springs (411) at its center. The upper and lower ball heads of the ball head assembly (410) form an upper annular channel T1 and a lower annular channel T2 with the center holes of the upper valve seat (404) and the lower valve seat (412), respectively. The function of the two support springs (411) is to prevent the upper and lower ball heads from contacting the sealing surface of the ball seat when there is liquid flow in the upper annular channel T1 and the lower annular channel T2 at the same time, so as to ensure that the channel is unobstructed. When the high pressure pump pressurizes, the liquid enters the flow distributor (400) through the central tube (301), enters the central channel T through the main inlet hole, and then splits into two paths: one path flows through the upper annular channel T1 and the outlet hole, pushes open the upper valve (403) and leaves the upper annular channel T1. After losing some pressure, the valve seat (404) enters the sealed space formed by the expansion assembly (300) and the auxiliary tube assembly (100), pushing the upper expansion cone (302) upward; another flow passes through the lower annular channel T2 and the lower outlet hole, pushing the lower valve (413) away from the lower valve seat (412), and after losing some pressure, enters the sealed space formed by the expansion assembly (300) and the auxiliary tube assembly (100), pushing the lower expansion cone (302) downward. The flow rates of the two liquids are the same. At the same time as the two liquids flow out from the valve and the valve seat, a pressure drop of 0.5MPa-0.8MPa is generated due to the action of the pressure regulating spring. The pressure difference between the inside and outside causes the rubber sleeve (406) to expand and stick to the inner wall of the auxiliary tube (101).

5. A sealing patch tool according to claim 4, characterized in that: The flow rate at which the ball head assembly (410) begins to move is set to 3-4 times the normal flow rate of the upper annular channel T1 and the lower annular channel T2. When a certain expansion cone (302) reaches its position, the liquid pressure drops. If the upper expansion cone (302) reaches its position first, all the liquid will flow out through the upper annular channel T1. When its flow rate reaches the designed value for the ball head assembly (410) to begin moving, the ball head assembly (410) moves upward, so that the ball head sealing surface contacts the ball seat sealing surface. The liquid flow in the upper annular channel T1 is blocked. At this time, the liquid can only enter the closed space formed by the expansion assembly (300) and the auxiliary tube assembly (100) through the lower annular channel T2 and the lower outlet hole, pushing open the lower valve (413). As the pressure rises, the rubber sleeve (406) expands to prevent the liquid from flowing to the expanded area. When the pressure rises to a certain value, the leaking port of the expanded upper sealing suspension (200) will continue to expand the sealing suspension (200) until it is fully expanded. When the lower sealing suspension (200) is fully expanded, the liquid will flow into the wellbore through the lower sealing suspension (200), the system pressure will drop, and the liquid will flow out through the lower annular channel T2. When its flow rate reaches the designed value for the ball head assembly (410) to start moving, the ball head assembly (410) will move downwards, and the upper annular channel T1 will be reopened. At this time, since both the upper and lower ends of the auxiliary pipe assembly (100) are connected to the wellbore, the ball head assembly (410) will return to its original position under the action of the support spring. The pressure in the tubing can no longer be increased, indicating that the auxiliary pipe assembly (100) has been attached to the well casing.

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