A large-diameter casing patching process string and patching method

Abstract

The application discloses a large-diameter casing patching process pipe column and a patching method. The method comprises the following steps: using a full-size well-through process pipe column to pass through a well, and determining whether the casing is deformed or the deformation condition; and using a large-diameter casing patching process pipe column to patch the damaged casing. The large-diameter casing patching process pipe column comprises an expansion pipe patching execution assembly, the expansion pipe patching execution assembly comprises an adjusting central pipe, an anchor shoe locking mechanism and a hydraulic cylinder mechanism; the anchor shoe locking mechanism is sleeved on the adjusting central pipe and is used for fixing the expansion pipe clamp lock on the inner wall of the casing; the hydraulic cylinder mechanism is arranged at the lower end of the adjusting central pipe, and the expansion pipe base pipe is fixed on the inner wall of the plugging section casing in a mode of constant pressurization, expansion and pressure relief; the process pipe column and the patching method can realize repeated patching of multiple sections with the same diameter, the process is simple, and processes such as bottom plugging treatment and well mouth repairing are not needed, and the whole process is completed by one pipe column.

Description

Technical Field

[0001] This invention relates to the field of casing repair technology, and in particular to a large-diameter casing patching process string and patching method. Background Technology

[0002] With the continuous development of oil and water well exploitation, casing damage in oilfields is becoming increasingly serious due to various engineering and geological factors. Casing damage has become a severe problem facing oilfield production both domestically and internationally. Currently, commonly used casing repair technologies mainly include chemical plugging, mechanical or hydraulic reshaping, casing reinforcement with padding, small casing reinforcement, and sidetracking wellbore reconstruction. Among these, casing plugging, reshaping, and small casing reinforcement technologies generally suffer from low repair success rates, short repair durations, and significant internal diameter reduction after casing repair, affecting oil and water well productivity development and limiting the application of large-size tools. In older oilfields, the number of wells with casing damage gradually increases in the later stages of development, making expansion tubing padding technology an important technical means to improve wellbore performance.

[0003] Currently, conventional internal patching technology is used. Initial wellbore preparation work employs conventional wellbore cleaning techniques. For 5 1 / 2" casing, a Φ116 wellbore gauge is generally selected. However, the condition of the Φ116-Φ124 radial section is unknown. If the casing is deformed within this section, it will affect the patching quality. Figure 2 As shown, during the subsidy process, an internal expansion head is used, driven by a single-stage piston, and a blind tube is designed at the tail end. Before the subsidy string is inserted into the well, the expansion head needs to be prefabricated on the ground and inserted into the casing. After the expansion operation is completed, another drilling and milling string is needed to drill out the blind tube. The operation time is long, and the casing has a large inner diameter after repair, resulting in a small inner diameter. For example, the inner diameter of a 5 1 / 2" casing after subsidy is Φ103-Φ110mm. The small inner diameter and low pressure resistance after subsidy restrict the implementation of water injection, fracturing and other measures, and affect the promotion and implementation of the subsidy technology.

[0004] The casing patching technology published in the 2008 issue of Petroleum Machinery, Volume 36, No. 12, entitled "Research and Application of Expansion Tube Reinforcement Technology", is for 5 1 / 2" casing. After patching, the inner diameter is 109-110mm and the pressure is 15MPa. After the expansion head is pulled out with the tubing, the bottom plug also needs to be retrieved. Summary of the Invention

[0005] The purpose of this invention is to provide a large-diameter sleeve patching process string and patching method.

[0006] Therefore, the technical solution of the present invention is as follows:

[0007] A large-diameter sleeve-mounted process string includes an expansion tube mounting assembly, wherein the expansion tube is sleeved on the outside of the expansion tube mounting assembly.

[0008] The expansion tube patching assembly includes an adjusting center tube, an anchor locking mechanism, and a hydraulic cylinder mechanism. The expansion tube patching assembly is connected to the oil pipe via a variable thread on the adjusting center tube. The anchor locking mechanism is sleeved on the adjusting center tube and is used to lock and fix the expansion tube to the inner wall of the casing. The hydraulic cylinder mechanism is located at the lower end of the adjusting center tube and fixes the expansion tube base tube to the inner wall of the sealing section casing by continuously pressurizing, expanding, and depressurizing, thereby achieving patching of the large-diameter casing.

[0009] Furthermore, the anchor bolt locking mechanism includes an upper limit body for the anchor bolt, an outer sheath for the anchor bolt, an adjusting spring for the anchor bolt, an adjusting spring washer for the anchor bolt, an anchor bolt for the padding assembly, a shear ring cap for the shear ring, and a release shear ring for the padding assembly.

[0010] The upper limit body of the anchor tile is fixed to the oil pipe. The upper part of the outer sheath of the anchor tile is connected to the upper limit body of the anchor tile, and the lower part is connected to the anchor tile of the auxiliary assembly, protecting the internal anchor tile adjusting spring and the anchor tile adjusting spring washer. The anchor tile of the auxiliary assembly is anchored to the oil pipe to prevent the oil pipe from moving upward during the casing auxiliary process. The release shear ring of the auxiliary assembly is set at the lower end of the outer sheath of the anchor tile and is used to connect the outer sheath of the anchor tile to the expansion tube.

[0011] Furthermore, the hydraulic cylinder mechanism includes a piston inner tube, an expansion head, a moving piston, a piston inner tube connector, a moving piston cylinder, a check valve outer sheath, a check valve inner sheath, a check valve spring, a check valve stem, a check valve seat, a check valve ball, and a supplementary assembly guide head;

[0012] The piston inner tube is connected to the last downhole tubing via a variable-thread connection and is clearance-fitted with other components of the hydraulic cylinder mechanism; the expansion head is simultaneously fixed to the moving piston and the moving piston cylinder; the moving piston, piston inner tube connector, one-way valve outer sheath, one-way valve inner sheath, and one-way valve seat are connected sequentially from top to bottom; the one-way valve stem is connected and fixed to the one-way valve inner sheath via the one-way valve spring; the one-way valve ball sits on the one-way valve seat, with the top of the one-way valve ball contacting the one-way valve stem; the auxiliary assembly guide head is fixed to the bottom of the moving piston cylinder and forms a fit with the bottom channel of the one-way valve seat.

[0013] Furthermore, the anchor bolt locking mechanism is a single anchor bolt locking mechanism or multiple anchor bolt locking mechanisms connected in series; the hydraulic cylinder mechanism is a single hydraulic cylinder mechanism or multiple single hydraulic cylinder mechanisms connected in series, but the outer diameter of the expansion head connected in series is slightly smaller than the outer diameter of the expansion head.

[0014] A method for subsidizing tubing based on the above-mentioned large-diameter sleeve subsidizing process string includes the following steps:

[0015] 1) Use a full-size wellbore cleaning process string to clean the well and determine whether the casing is deformed or the extent of deformation;

[0016] 2) Use large-diameter sleeves to repair damaged sleeves in the process tubing.

[0017] Furthermore, in step 1), a full-size well-through process string is used for well-through operation.

[0018] The full-size wellbore cleaning process string includes a wellbore gauge base, a wellbore gauge return spring, a wellbore gauge spring fixing pin, a wellbore gauge spring connecting pin, a wellbore gauge linkage limit block, a wellbore gauge variable diameter adjustment body, a wellbore gauge control ball, a linkage fluid inlet hole, and an adjustment body positioning hole.

[0019] The well gauge base is designed with a linkage fluid inlet and an adjustment body positioning hole; the upper end of the well gauge return spring is fixed to the well gauge base by a well gauge spring fixing pin, and the lower end of the well gauge return spring is fixed to the well gauge linkage limit block by a well gauge spring connecting pin; the well gauge variable diameter adjustment body is fixed in the well gauge base's designed groove; the well gauge base's designed groove has a limit, and the well gauge variable diameter adjustment body will not move after moving to the designed position, preventing the well gauge variable diameter adjustment body from falling off the well gauge base; the well gauge control ball is on the reduced diameter step at the bottom of the well gauge base, so that the full-size well cleaning process string is in a one-way sealed state.

[0020] Furthermore, the method for determining whether the sleeve is deformed is as follows:

[0021] If the workover rig load increases during the upward movement of the full-size wellbore process string, the casing will deform at that location.

[0022] Furthermore, the method for patching the damaged sleeve in step 2) includes:

[0023] 2-1) Lower the expansion tube subsidy assembly into the designated position;

[0024] 2-2) Use the anchor bolt locking mechanism to lock and fix the expansion tube to the inner wall of the casing;

[0025] 2-3) Pressurize the oil pipe. The pressure is transmitted through the moving piston to drive the hydraulic cylinder mechanism to generate an upward thrust. The thrust acts on the expansion head, causing the expansion pipe to be subjected to a radial outward force from the bottom of the expansion pipe base, thus causing it to expand.

[0026] 2-4) Perform a pressure relief operation. When the hydraulic cylinder mechanism moves upward by L, the ball needle inside the guide head of the auxiliary assembly will push open the ball of the check valve, so that a channel is formed at the bottom of the check valve seat for pressure relief.

[0027] 2-5) Lift the oil pipe and repeat the pressurization, expansion, and depressurization steps until the expansion inner diameter meets the requirements, so that the expansion pipe base pipe is firmly fixed to the inner wall of the casing of the sealing section through the expansion pipe sealing body.

[0028] 2-6) Remove the expansion tool, use the release shear ring to separate the anchor bolt locking mechanism from the expansion tube, lift the oil pipe, and remove all the expansion tube and auxiliary actuator assemblies connected below.

[0029] Compared with existing technologies, this large-diameter casing patching process uses a steel-to-steel main seal and a micro-gap auxiliary seal, resulting in high anchoring force, high temperature resistance, and a casing pressure-bearing capacity of up to 70MPa after patching. The expansion head is externally positioned, and the expansion tube fits tightly with the 139.7mm outer diameter casing. After expansion, the inner diameter can reach 112-116mm (124mm inner diameter casing) or 111-112mm (121mm inner diameter casing), allowing large-size downhole tools to pass through the patched tube for subsequent operations.

[0030] It can achieve repeated patching of multiple sections of the same diameter, full-size casing wellbore cleaning, and high casing repair success rate; the casing patching process is simple, without bottom plugging treatment, top repair and other procedures, the entire process can be completed in one trip of tubing string, shortening operation time and increasing operation efficiency. After patching, no debris is left in the well, which will not have an adverse impact on subsequent procedures; the expansion start-up and travel pressure is low, which is 0.5-0.6 times that of conventional expansion tubing construction pressure, making on-site operation safer and more reliable. Attached Figure Description

[0031] Figure 1 This is a diagram showing the state of the full-size wellbore process tubing before it enters the well.

[0032] Figure 2 This is the well-drilling state of the full-size well-drilling process tubing string.

[0033] Figure 3 The process string for large-diameter casing is in the wellhead.

[0034] Figure 4 The process tubing is in an expanded state for the large-diameter sleeve.

[0035] Figure 5 This is a schematic diagram of the external large-diameter sleeve after subsidies. Detailed Implementation

[0036] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but the following embodiments are by no means intended to limit the present invention.

[0037] Unless the context clearly indicates otherwise. It should also be understood that the term "and / or" as used in one or more embodiments of this application refers to, and many specific details are set forth in the following description to provide a full understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of this application; therefore, this application is not limited to the specific embodiments disclosed below.

[0038] The terminology used in one or more embodiments of this application is for the purpose of describing particular embodiments only and is not intended to limit the scope of one or more embodiments of this application. The singular forms “a,” “the,” and “the” used in one or more embodiments of this application and in the appended claims are also intended to include the plural forms, encompassing any or all possible combinations of one or more associated listed items.

[0039] It should be understood that although the terms first, second, etc., may be used to describe various information in one or more embodiments of this application, such information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, first may also be referred to as second without departing from the scope of one or more embodiments of this application, and similarly, second may also be referred to as first. Depending on the context, the word "if" as used herein may be interpreted as "when," "when," or "in response to a determination."

[0040] This invention provides a large-diameter casing patching process string and method consisting of two steps: the first step is to run a full-size wellbore cleaning process string to clean the well and determine whether the casing is deformed or the extent of deformation; the second step is to patch the casing according to the corresponding external large-diameter casing patching process string.

[0041] It should be noted that the above-mentioned subsidy method can also achieve secondary casing compensation. If there is casing damage below the subsidy section, firstly, a full-size wellbore process string is used to circulate the well through the original subsidy section. Then, an external large-diameter casing compensation process string using a variable-diameter expansion head is run in to compensate, thereby compensating for the casing below the subsidy section.

[0042] Example 1:

[0043] The structure of the full-size wellbore string used in the large-diameter casing patching method provided by this invention is as follows: Figure 1-2 As shown.

[0044] The main components include: tubing 1, casing 2, full-size wellbore cleaning process string 3, wellbore gauge base 301, wellbore gauge return spring 302, wellbore gauge spring fixing pin 303, wellbore gauge spring connecting pin 304, wellbore gauge linkage limit block 305, wellbore gauge diameter adjustment body 306, wellbore gauge control ball 307, linkage fluid inlet hole 30101, adjustment body positioning hole 30102, etc.

[0045] The tubing 1 is connected to the full-size wellbore process string 3 to form the full-size wellbore process string; the wellbore gauge base 301 is designed with a linkage fluid inlet 30101 and an adjustment body positioning hole 30102; the upper end of the wellbore gauge return spring 302 is fixed to the wellbore gauge base 301 by the wellbore gauge spring fixing pin 303; the lower end of the wellbore gauge return spring 302 is fixed to the wellbore gauge linkage limit block 305 by the wellbore gauge spring connecting pin 304; the wellbore gauge variable diameter adjustment body 306 is fixed in the designed groove of the wellbore gauge base 301; there is a limit in the designed groove of the wellbore gauge base 301, and the wellbore gauge variable diameter adjustment body 306 will not move after moving to the designed position, to prevent the wellbore gauge variable diameter adjustment body 306 from falling off the wellbore gauge base 301; the wellbore gauge control ball 307 is on the reduced diameter step at the bottom of the wellbore gauge base 301, so that the full-size wellbore process string 3 is in a one-way sealed state.

[0046] The working principle of the above full-size wellbore cleaning process string is as follows:

[0047] When the full-size wellbore process string is in such a state Figure 1 When the full-size wellbore process string is lowered into the designed position, the wellbore gauge control ball 307 is inserted, the tubing 1 is pressurized, and the wellbore gauge variable diameter adjustment body 306 is moved outward from the wellbore gauge base 301 design groove under hydraulic pressure until it reaches the wellbore gauge base 301 design groove limit mechanism and contacts the inner wall of the casing 2.

[0048] At the same time, under the action of hydraulic pressure, the well gauge linkage limit block 305 moves downward and stretches the well gauge reset spring 302. The well gauge linkage limit block 305 moves to the bottom of the well gauge diameter adjustment body 306 to prevent the well gauge diameter adjustment body 306 from resetting.

[0049] The full-size wellbore process string 3 is moved upward under pressure to achieve full-size wellbore clearance of casing 2.

[0050] After well cleaning is completed, the pressure relief well cleaning gauge linkage limit block 305 moves upward under the action of the well cleaning gauge reset spring 302, and the well cleaning gauge variable diameter adjustment body 306 returns to its initial position.

[0051] If the well gauge linkage limit block 305 does not reset after depressurization, pressurize the annulus and hydraulically push the well gauge linkage limit block 305 to reset.

[0052] If the load on the workover rig increases during the upward movement of the full-size well-through process string 3, the casing 2 will deform at that position.

[0053] By replacing the smaller well gauge variable diameter adjustment body 306, it was determined that the casing 2 had a deformed dimension at this position, which guided the next step of the external large diameter casing patching process.

[0054] The well gauge linkage limit block 305 drives the well gauge diameter adjustment body 306 by applying pressure.

[0055] The well gauge control ball 307 can be inserted into the bottom 301 of the well gauge base of the full-size well-gazing process string 3 through the tubing 1, so that the full-size well-gazing process string 3 is in a sealed state.

[0056] Example 2:

[0057] This invention provides a large-diameter sleeve-supported process tubing string, the structure of which is as follows: Figure 3-4 As shown:

[0058] The assembly includes an expansion tube subsidy execution assembly 4, with the expansion tube 5 sleeved on the outside of the expansion tube subsidy execution assembly 4. The expansion tube subsidy execution assembly 4 consists of an upper buckle 401 of the adjusting center tube, an adjusting center tube 402, an upper limit body of the anchor tile 403, an outer sheath of the anchor tile 404, an anchor tile adjusting spring 405, an anchor tile adjusting spring washer 406, an anchor tile of the subsidy assembly 407, a shear ring cap 408, a release shear ring of the subsidy assembly 409, a lower buckle 410 of the adjusting center tube, an inner piston tube 411, an expansion head 412, a moving piston 413, an inner piston tube connector 414, a moving piston cylinder 415, an outer sheath of the one-way valve 416, an inner sheath of the one-way valve 417, a one-way valve spring 418, a one-way valve rod 419, a one-way valve seat 420, a one-way valve ball 421, and a guide head of the subsidy assembly 422.

[0059] The upper end of the regulating center tube 402 is connected to the oil pipe 1 through the regulating center tube upper buckle 401.

[0060] The expansion tube subsidy assembly 4 consists of an anchor tile upper limit body 403, an anchor tile outer sheath 404, an anchor tile adjusting spring 405, an anchor tile adjusting spring washer 406, a subsidy assembly anchor tile 407, a shear ring cap 408, and a subsidy assembly release shear ring 409, which together form an anchor tile locking mechanism to lock and fix the expansion tube 5 to the inner wall of the sleeve 2.

[0061] The upper limit body 403 of the anchor shoe is fixed to the tubing 1. The upper part of the outer sheath 404 of the anchor shoe is connected to the upper limit body 403, and the lower part of the outer sheath 404 is connected to the anchor shoe 407 of the adapter assembly, protecting the internal anchor shoe adjusting spring 405 and anchor shoe adjusting spring washer 406. The anchor shoe 407 of the adapter assembly is anchored to the tubing 1 to prevent the tubing 1 from moving upwards during the casing adapter process.

[0062] To improve anchoring reliability, multiple anchor locking mechanisms can be designed in series.

[0063] The expansion tube subsidy assembly 4 comprises a piston inner tube 411, an expansion head 412, a moving piston 413, a piston inner tube connector 414, a moving piston cylinder 415, a check valve outer sleeve 416, a check valve inner sleeve 417, a check valve spring 418, a check valve rod 419, a check valve seat 420, a check valve ball 421, and a subsidy assembly guide head 422, which together form a hydraulic cylinder mechanism. The piston inner tube 411 is connected to the lower end of the adjusting center tube 402 via the adjusting center tube lower buckle 410.

[0064] The piston inner tube 411 is connected to the last downhole tubing 1 via a variable-thread connection and has a clearance fit with other components of the hydraulic cylinder mechanism. The expansion head 412 is fixed to the moving piston 413 and the moving piston cylinder 415. The moving piston 413, piston inner tube connector 414, check valve outer sleeve 416, check valve inner sleeve 417, and check valve seat 420 are connected sequentially from top to bottom. The check valve stem 419 is connected and fixed to the check valve inner sleeve 417 via the check valve spring 418. The check valve ball 421 sits on the check valve seat 420, with its top contacting the check valve stem 419. The auxiliary assembly guide head 422 is fixed to the bottom of the moving piston cylinder 415 and forms a fit with the bottom channel of the check valve seat 420.

[0065] The expansion head 412 can use a full-size wellbore process string 3, which is not limited by the inner diameter of the wellbore. It can be lowered to the position below the plugging section with a smaller size, and then expanded to a larger outer diameter (116mm). This ensures that the expansion tube can be expanded to a larger inner diameter, so as to achieve casing replacement with a larger diameter and realize casing replacement. The expansion size is about 10mm larger in diameter than the conventional structure.

[0066] To increase the expansion force of the expansion head 412, multiple hydraulic cylinders can be designed in series, but the outer diameter of the series expansion heads (115mm) should be slightly smaller than the outer diameter of the expansion head 412 (116mm).

[0067] The expansion tube 5 consists of an expansion tube base tube 501 and an expansion tube sealing body 502. The expansion tube sealing body 502 is on the outer wall of the expansion tube base tube 501 and contacts and seals with the sleeve 2.

[0068] The expansion tube seal 502 rubber is vulcanized onto the expansion tube base tube 501 to improve the sealing ability, and multiple and no less than 10 expansion tube seals 502 are vulcanized on the expansion tube base tube 501 to ensure a pressure bearing capacity of 70MPa.

[0069] Example 3:

[0070] The present invention provides a method for patching large-diameter sleeves, as detailed below:

[0071] like Figure 5As shown, after the external large-diameter sleeve repair process string is lowered into the designed position, the expansion tube 5 is aligned with the damaged position of the sleeve 2 that needs to be repaired, and the sleeve 2 is sealed and repaired.

[0072] The locking mechanism, consisting of the upper limit body 403, outer sheath 404, adjusting spring 405, adjusting spring washer 406, anchor assembly anchor 407, shear ring cap 408, and shear ring release 409 connected together, locks the expansion tube 5 onto the inner wall of the sleeve 2. At the same time, the anchor 407 of the anchor assembly, under the weight of the adjusting center tube 402 and the force of the anchor adjusting spring 405, fixes the adjusting center tube 402 and the connected tools below it at the anchor, which can prevent the expansion tube 5 from being displaced by the upward thrust during the expansion operation.

[0073] It should be noted that the subsidy process mainly includes the following steps:

[0074] (1) Pressurization and expansion:

[0075] like Figure 4 , Figure 5 When oil pipe 1 is pressurized, the pressure is transmitted through moving piston 413 to drive the hydraulic cylinder mechanism (expansion head 412, moving piston 413, piston inner tube connector 414, moving piston cylinder 415, check valve outer sleeve 416, check valve inner sleeve 417, check valve spring 418, check valve rod 419, check valve seat 420, check valve ball 421, and auxiliary assembly guide head 422) to generate an upward thrust. The thrust acts on expansion head 412, causing expansion pipe 5 to be subjected to radial outward force from the bottom of expansion pipe base pipe 501, thus causing it to expand.

[0076] (2) Pressure relief:

[0077] When the hydraulic cylinder mechanism moves upward by L, the ball needle inside the guide head 422 of the auxiliary assembly will push open the one-way valve ball 421, so that a channel is formed at the bottom of the one-way valve seat 420 for pressure relief.

[0078] (3) Raise the oil pipe:

[0079] The oil pipe 1 is lifted by a stroke distance of L, which causes the piston inner tube 411, moving piston 413, piston inner tube connector 414, moving piston cylinder 415, check valve outer sleeve 416, check valve inner sleeve 417, check valve spring 418, check valve stem 419, check valve seat 420, and check valve ball 421 below the oil pipe 1 to move upward by a stroke distance of L.

[0080] When the oil pipe 1 is lifted, the anchor bolt locking mechanism can be unlocked and will not move upward with the oil pipe 1.

[0081] Repeat the steps of pressurizing, expanding, depressurizing, and lifting the oil pipe until the inner diameter of the expansion pipe 5 expands (116mm), so that the expansion pipe 5, through the expansion pipe sealing body 502, firmly fixes the expansion pipe base pipe 501 to the inner wall of the casing 2 of the sealing section. After the casing is repaired, the pressure can reach 70MPa.

[0082] For example, if the push stroke L is 700mm each time, it is necessary to repeat the pressurization 12 times to complete the patching of an 8m expansion tube.

[0083] (4) Propose expansion tools:

[0084] Cut the shear ring 409 of the subsidy assembly to separate the anchor bolt locking mechanism, which consists of the upper limit body 403, the outer sleeve 404, the adjusting spring 405, the adjusting spring washer 406, the anchor bolt assembly anchor bolt 407, the shear ring cap 408, and the shear ring 409, from the expansion tube 5. Then, lift the oil pipe 1 to remove all the expansion tube subsidy execution assemblies 4 connected below.

[0085] The casing subsidy process is completed without the need for drilling and plugging the bottom, as is the casement subsidy process. The well string can be run directly and the product can be put into production.

[0086] Furthermore, this method can also be used to repair damaged casing below the original repair location, achieving casing-in-casing repair. The wellbore cleaning and repair technology principles are the same as the original scheme, but the expansion head 412 can only use the structure of the full-size wellbore cleaning process string 3.

[0087] The preferred embodiments disclosed above are merely illustrative of this application. The optional embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the embodiments of this application. These embodiments are selected and specifically described in this application to better explain the principles and practical applications of the embodiments of this application, thereby enabling those skilled in the art to better understand and utilize this application. This application is limited only by the claims and their full scope and equivalents.

Claims

1. A large-diameter sleeve-supported process tubing string, characterized in that, Includes an expansion tube subsidy assembly, wherein the expansion tube is sleeved on the outside of the expansion tube subsidy assembly; The expansion tube subsidy assembly includes an adjusting center tube, an anchor locking mechanism, and a hydraulic cylinder mechanism. The expansion tube subsidy assembly is connected to the oil pipe via a variable thread on the adjusting center tube. The anchor locking mechanism is sleeved on the adjusting center tube and is used to lock and fix the expansion tube to the inner wall of the casing. The hydraulic cylinder mechanism is located at the lower end of the adjusting center tube and fixes the expansion tube base tube to the inner wall of the sealing section casing by continuously pressurizing, expanding, and depressurizing, thereby achieving the subsidy of the large-diameter casing. The hydraulic cylinder mechanism includes an inner piston tube, an expansion head, a moving piston, an inner piston tube connector, a moving piston cylinder, a one-way valve outer sheath, a one-way valve inner sheath, a one-way valve spring, a one-way valve stem, a one-way valve seat, a one-way valve ball, and a guide head for the auxiliary assembly. The piston inner tube is connected to the last downhole tubing via a variable-thread connection and is clearance-fitted with other components of the hydraulic cylinder mechanism; the expansion head is simultaneously fixed to the moving piston and the moving piston cylinder; the moving piston, piston inner tube connector, one-way valve outer sheath, one-way valve inner sheath, and one-way valve seat are connected sequentially from top to bottom; the one-way valve stem is connected and fixed to the one-way valve inner sheath via the one-way valve spring; the one-way valve ball sits on the one-way valve seat, with the top of the one-way valve ball contacting the one-way valve stem; the auxiliary assembly guide head is fixed to the bottom of the moving piston cylinder and forms a fit with the bottom channel of the one-way valve seat.

2. The large-diameter sleeve-supported process tubing string according to claim 1, characterized in that, The anchor bolt locking mechanism includes an upper limit body for the anchor bolt, an outer sheath for the anchor bolt, an adjusting spring for the anchor bolt, an adjusting spring washer for the anchor bolt, an anchor bolt with a shear ring cap, and an anchor bolt with a release shear ring. The upper limit body of the anchor tile is fixed to the oil pipe. The upper part of the outer sheath of the anchor tile is connected to the upper limit body of the anchor tile, and the lower part is connected to the anchor tile of the auxiliary assembly, protecting the internal anchor tile adjusting spring and the anchor tile adjusting spring washer. The anchor tile of the auxiliary assembly is anchored to the oil pipe to prevent the oil pipe from moving upward during the casing auxiliary process. The release shear ring of the auxiliary assembly is set at the lower end of the outer sheath of the anchor tile and is used to connect the outer sheath of the anchor tile to the expansion tube.

3. The large-diameter sleeve-supported process tubing string according to claim 2, characterized in that, The anchor bolt locking mechanism is a single anchor bolt locking mechanism or multiple anchor bolt locking mechanisms connected in series; the hydraulic cylinder mechanism is a single hydraulic cylinder mechanism or multiple single hydraulic cylinder mechanisms connected in series, but the outer diameter of the expansion head connected in series is slightly smaller than the outer diameter of the expansion head.

4. A method for patching a large-diameter casing patching process string as described in claim 1, characterized in that, Includes the following steps: 1) Use a full-size wellbore cleaning process string to clean the well and determine whether the casing is deformed or the extent of deformation; 2) Use large-diameter casing to repair damaged casings using the process tubing.

5. The method for patching a large-diameter casing process tubing string according to claim 4, characterized in that, Step 1) involves performing well cleaning operations using a full-size well cleaning process string. The full-size wellbore cleaning process string includes a wellbore gauge base, a wellbore gauge return spring, a wellbore gauge spring fixing pin, a wellbore gauge spring connecting pin, a wellbore gauge linkage limit block, a wellbore gauge variable diameter adjustment body, a wellbore gauge control ball, a linkage fluid inlet hole, and an adjustment body positioning hole. The well gauge base is designed with a linkage fluid inlet and an adjustment body positioning hole; the upper end of the well gauge return spring is fixed to the well gauge base by a well gauge spring fixing pin, and the lower end of the well gauge return spring is fixed to the well gauge linkage limit block by a well gauge spring connecting pin; the well gauge variable diameter adjustment body is fixed in the well gauge base's designed groove; the well gauge base's designed groove has a limit device, so the well gauge variable diameter adjustment body will not move after moving to the designed position, preventing the well gauge variable diameter adjustment body from falling off the well gauge base; the well gauge control ball is on the reduced diameter step at the bottom of the well gauge base, so that the full-size well cleaning process string is in a one-way sealed state.

6. The method for patching a large-diameter casing process tubing string according to claim 5, characterized in that, The method for determining whether the sleeve is deformed is as follows: If the workover rig load increases during the upward movement of the full-size wellbore process string, the casing will deform at that location.

7. The method for patching a large-diameter casing process string according to any one of claims 4-6, characterized in that, The method for patching the damaged sleeve in step 2) includes: 2-1) Lower the expansion tube subsidy assembly into the designated position. 2-2) Use the anchor bolt locking mechanism to lock and fix the expansion tube to the inner wall of the casing; 2-3) Pressurize the oil pipe. The pressure is transmitted through the moving piston to drive the hydraulic cylinder mechanism to generate an upward thrust. The thrust acts on the expansion head, causing the expansion pipe to be subjected to a radial outward force from the bottom of the expansion pipe base, thus causing it to expand. 2-4) Perform pressure relief operation. When the hydraulic cylinder mechanism moves upward by L, the ball needle inside the guide head of the auxiliary assembly will push open the one-way valve ball, so that a channel is formed at the bottom of the one-way valve seat for pressure relief. 2-5) Lift the oil pipe and repeat the pressurization, expansion, and depressurization steps until the expansion inner diameter meets the requirements, so that the expansion pipe base pipe is firmly fixed to the inner wall of the casing of the sealing section through the expansion pipe sealing body; 2-6) Remove the expansion tool, use the release shear ring to separate the anchor bolt locking mechanism from the expansion tube, lift the oil pipe, and remove all the expansion tube and auxiliary actuator assemblies connected below.

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