Device and method for repairing deformed casing in oil and gas field production well

Abstract

The invention relates to the technical field of oil and gas field production, in particular to a device and method for repairing a deformed casing pipe in an oil and gas field production well, and the device comprises a high-pressure barrel, a low-pressure barrel, an extrusion plunger and a pressurization piston. The device is reasonable and compact in structure, when the device is used, after the high-pressure barrel and the extrusion plunger are assembled, hydraulic oil is added into the high-pressure acting cavity to reach a set value, the high-pressure barrel and the low-pressure barrel are connected, then the low-pressure barrel and the pipe string are connected and then are put into a target position in a sleeve, and then power liquid is added into the pipe string; after the pressure of the power liquid is increased to a set value, the pressure is kept for a certain time, the high-pressure power liquid acts on the pressurizing piston to enable the pressurizing piston to move downwards, and after the pressurizing piston moves downwards, the extrusion plunger extends outwards to extrude the deformed part in the casing pipe, so that the repair operation of the deformed part of the casing pipe is completed. According to the method, the repair of the deformed casing pipe in the horizontal well section can be completed, the casing pipe can be repaired under the working condition with pressure, and the casing pipe repair efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field of oil and gas field production, and relates to a device and a method for repairing a deformed casing in a production well of an oil and gas field. Background Art

[0002] During the production process of oil and gas fields, due to the complex formation pressure, the metal casing in the wellbore is deformed and the diameter becomes smaller. The subsequent construction tools cannot reach the destination, which seriously affects the production of the oil field and even causes the wellbore to be scrapped, resulting in serious economic losses to oil and gas production companies. In order to achieve normal production, oil and gas field companies generally use overhaul operations to repair deformed casing. At present, the main tools used to repair deformed casing are pear-shaped expanders, rotary shock shapers, eccentric roller shapers, three-cone roller casing shapers and deflagration shapers. In principle, these tools usually use gravity or impact force to force the deformed parts of the casing to expand and round, which is relatively inefficient and prone to extrusion and adhesion, resulting in drill jamming accidents. The cost of repairing deformed casing is very high.

[0003] The Chinese invention patent with publication number CN217501613U discloses a hydraulic casing shaper, including an upper joint, an outer cylinder, a guide cone plug, a spring, an expansion shaft, an expansion body and a plugging steel ball. The upper end of the upper joint has a connection structure, and the lower end is provided with an external thread. The upper end of the guide cone plug is provided with an external thread, and the lower end is provided with a conical guide surface. The upper and lower ends of the outer cylinder are respectively connected with the upper joint and the guide cone plug by threads. The side wall is provided with an expansion window with a limited position support ear on the outer edge. The expansion shaft is set on the outer In the inner cavity of the cylinder, the upper end is limited by the upper joint, and the lower end is supported by a spring. The upper end axial hole of the expansion shaft is provided with a conical sealing surface corresponding to the sealing steel ball structure, and a receiving groove with a guide slope along the upper end is provided on the outer circumferential surface of the expansion shaft. The hydraulic casing shaper uses hydraulic control to balance the force of the expansion block to trim the downhole casing, and adopts a guiding method combining the end guide cone and the spiral arrangement of the expansion block. It is preferred that the expansion body uses an expansion roller and an expansion ball structure and is arranged in different areas to improve the shaping effect and shaping efficiency. The device uses internal pressure in the pipe column to push the cone-shaped core shaft downward to squeeze the shaping rollers evenly distributed in the circumferential direction outward to repair the deformed casing. The disadvantage of this device is that after the pressure is released, the core shaft is reset by the spring. If it is stuck tightly, the spring force will be insufficient to push the core shaft, and the tool will also get stuck.

[0004] The Chinese invention patent casing hydraulic shaping device with publication number CN207499831U is composed of a pressure relief device, a hydraulic anchor device, a hydraulic power device, and a reducer shaper; the pressure relief device, the hydraulic anchor device, the hydraulic power device, and the reducer shaper are connected from top to bottom by threads. The device requires the anchor claws to bite the casing wall to provide support, and the hydraulic cylinder pushes the mandrel to push the repair roller outward by the conical structure to repair the casing. The anchor claws need to withstand a sufficiently large thrust. This will cause certain bites to the casing, affecting the life of the casing, and can even break the casing with more serious corrosion.

[0005] The above casing hydraulic shaping device is suitable for shaping casing with slow deformation and small deformation, but it is inefficient for repairing casing with relatively large deformation and deformation gradient. The existing method for repairing deformed casing has a certain effect in vertical well sections. In the increasingly increasing number of horizontal wells and highly deviated well sections, deformed casing is prone to drill jamming accidents due to many shortcomings, making it difficult to repair deformed casing. Summary of the invention

[0006] The present invention provides a device and method for repairing deformed casing in oil and gas field production wells, which overcomes the shortcomings of the above-mentioned prior art and can effectively solve the problem that the existing deformed casing repairing device is difficult to repair casing with relatively large deformation amount and deformation gradient, resulting in low casing repair efficiency.

[0007] Furthermore, the present invention also solves the problem of low casing repair efficiency due to difficulty in repairing deformed casing in horizontal well sections existing in existing deformed casing repair devices.

[0008] One of the technical solutions of the present invention is achieved through the following measures: a device for repairing deformed casing in a production well of an oil and gas field, comprising a high-pressure cylinder, a low-pressure cylinder, an extrusion plunger and a boosting piston, a high-pressure action chamber with an opening upward and larger at the top and smaller at the bottom is provided at the upper end of the high-pressure cylinder, a low-pressure cylinder is sealed and fixedly installed at the upper end of the high-pressure cylinder, a low-pressure action chamber whose lower end is connected with the upper end of the high-pressure action chamber is provided at the upper end of the low-pressure cylinder, a plurality of staggered and radially penetrating sliding holes are provided at intervals at upper and lower intervals on the outer side of the lower part of the high-pressure cylinder corresponding to the position of the small-diameter section of the high-pressure action chamber, a pair of extrusion plungers are sealed and slidably installed in each sliding hole, a boosting piston is sealed and slidably installed in the low-pressure action chamber, and each extrusion plunger can extend outward after the lower end moves downward, and an elastic reset part that can move the boosting piston upward is installed on the inner side of the lower part of the low-pressure action chamber.

[0009] The following is a further optimization and / or improvement of one of the above-mentioned technical solutions: The projections of the central axes of the above-mentioned several sliding holes on the horizontal plane can be evenly spaced along the circumference, and an annular groove located on the inner wall of the high-pressure action chamber is provided between the end faces of each pair of extrusion plungers that are close to each other, and a limiting ring is installed in each annular groove. The outer side of each extrusion plunger is sealed with a sealing pressure cap that is screwed to the corresponding position of the sliding hole, and the end of each sealing pressure cap close to the high-pressure action chamber is fixed with a first sealing sleeve that is in sealing contact with the corresponding position of the sliding hole, and the outer side of the end of each extrusion plunger close to the limiting ring is fixed with a first outer ring platform that can move axially in the first sealing sleeve.

[0010] The first sealing sleeve corresponding to the position between the first outer ring platform and the sealing pressure cap can be equipped with a first buffer pad, and the lower end of the high-pressure cylinder is provided with an oil filling hole connected to the lower end of the high-pressure action chamber, and an oil filling plug is sealed and fixedly installed in the oil filling hole.

[0011] The inner side of the upper end of the high-pressure cylinder body can be sealed and fixedly installed with a connecting sleeve which is mounted on the outer side of the lower part of the boosting piston. The outer side of the upper part of the connecting sleeve and the inner side of the lower end of the low-pressure cylinder body are fixedly installed together. The boosting piston is T-shaped with a larger upper part and a smaller lower part. The outer side of the upper end of the boosting piston is sealingly and slidably installed on the inner side of the upper part of the low-pressure cylinder body. The inner side of the lower part of the connecting sleeve has a first step surface, and the upper end of the first step surface is spaced from bottom to top with a lower support ring and an upper support ring which are mounted on the outer side of the lower part of the boosting piston. A plurality of packing rings which are sealed and mounted on the outer side of the lower part of the boosting piston are stacked in sequence from bottom to top between the lower support ring and the upper support ring. A tubular packing pressure cap whose lower end is abutted against the upper support ring is fixedly installed on the inner side of the upper part of the connecting sleeve. The outer side of the upper part of the connecting sleeve has a second step surface, and at least one connecting hole which is connected to the inside and outside is distributed along the circumferential direction at intervals corresponding to the outer side of the lower part of the low-pressure cylinder body above the second step surface. The elastic reset part is mounted on the inner side of the low-pressure cylinder body between the lower end surface of the large diameter section of the boosting piston and the second step surface.

[0012] A first inner ring platform whose lower end abuts against the upper end of the boosting piston can be fixed on the inner side of the upper part of the low-pressure cylinder body, and a straightening cylinder whose upper end is located above the low-pressure cylinder body is sealed and fixed on the inner side of the upper end of the low-pressure cylinder body, and an injection tube whose upper end is located above the straightening tube is sealed and slidably installed in the straightening tube, and at least one external drainage hole connected inside and outside is circumferentially spaced apart on the outer side of the lower part of the injection tube corresponding to the position above the first inner ring platform, and a second outer ring platform with a spacing between the upper end and the lower end of the straightening tube is fixed on the outer side of the lower part of the injection tube, and at least one first sealing member is arranged between the outer side of the second outer ring platform corresponding to the position above the external drainage hole and the inner side of the low-pressure cylinder body, and at least one second sealing member is arranged between the inner side of the first inner ring platform and the outer side of the lower end of the injection tube, and at least one internal drainage hole connected inside and outside is circumferentially spaced apart on the outer side of the injection tube corresponding to the position above the second outer ring platform.

[0013] The outer side of the upper part of the above-mentioned straightening cylinder can be evenly distributed along the circumference with a plurality of straightening grooves opening outward, each straightening groove is fitted with a friction pin of a cylindrical structure, a third outer ring platform fitted in the straightening groove is fixed to the outer side of the end of the friction pin close to the inner wall of the straightening cylinder, a friction sleeve fitted on the outer side of the friction pin is fixedly installed in the straightening groove, and a compression spring is installed between the inner side of the friction pin and the inner wall of the straightening groove, which can make the end faces of the third outer ring platform and the friction sleeve abut against each other.

[0014] A conversion joint can be sealed and fixedly installed on the upper end of the straightening cylinder.

[0015] The end surface of the friction pin away from the straightening cylinder may be in the shape of a spherical crown.

[0016] The end surface of the sealing pressure cap away from the limiting ring can be fixed with a disassembly sleeve sleeved on the outside of the extrusion plunger, and the outer contour surface of the disassembly sleeve is hexagonal.

[0017] A conical transition surface with a larger upper portion and a smaller lower portion may be formed between the large diameter section and the small diameter section of the high pressure action chamber.

[0018] A second buffer pad and a third sealing member may be arranged in sequence from outside to inside between the end of the first sealing sleeve and the inner side of the sliding hole.

[0019] The end surface of the extrusion plunger away from the limiting ring may be in a spherical crown shape.

[0020] The outer side of the lower end of the high-pressure cylinder may be provided with a chamfered structure.

[0021] A third buffer pad and a fourth sealing member may be arranged in sequence from outside to inside between the outer side of the upper portion of the oil filling plug and the inner side of the oil filling hole.

[0022] The second technical solution of the present invention is achieved by the following measures: A method for repairing a deformed casing, characterized by comprising the following steps: The first step is to assemble a device for repairing a deformed casing in a production well of an oil and gas field, invert the device for repairing a deformed casing in a production well of an oil and gas field, remove the oil injection plug, extract the extrusion plunger, and inject hydraulic oil into the high-pressure cavity through the oil injection hole. The liquid level of the hydraulic oil rises to the oil injection hole when all the extrusion plungers are retracted, and then the oil injection plug is sealed and fixedly installed in the oil injection hole, and the device for repairing a deformed casing in a production well of an oil and gas field is assembled and turned over, and the conversion joint is connected to the pipe string; The second step is to lower the high-pressure cylinder into the deformation position of the casing; The third step is to inject power fluid into the pipe string, and the power fluid flows into the injection pipe through the conversion joint; The fourth step is to increase the power fluid pressure and stabilize it for a certain period of time; Step 5: Stop injecting the power fluid and lift the pipe string; Step 6: Repeat steps 2 to 5 until the repair of the deformed casing section is completed.

[0023] The present invention has a reasonable and compact structure. When in use, after the high-pressure cylinder and the extrusion plunger are assembled, hydraulic oil is added into the high-pressure action chamber to reach a set value, the high-pressure cylinder and the low-pressure cylinder are connected, and the low-pressure cylinder is connected to the pipe string and then lowered into the target position in the casing, and then power fluid is added to the pipe string, and the pressure of the power fluid is increased to the set value and maintained for a certain time. The high-pressure power fluid acts on the boosting piston to move the boosting piston downward. After the boosting piston moves downward, the extrusion plunger extends outward to squeeze the deformed part in the casing, thereby completing the repair operation of the deformed part of the casing. The present invention can also complete the repair of deformed casing in the horizontal well section, and can also perform casing repair under pressure conditions, thereby improving the efficiency of casing repair. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Attached Figure 1 It is a schematic diagram of the front cross-sectional structure of the first embodiment.

[0025] Attached Figure 2 For attachment Figure 1 Schematic diagram of the cross-sectional structure at AA in the middle.

[0026] Attached Figure 3 For attachment Figure 1 Schematic diagram of the cross-sectional structure at BB in the middle.

[0027] Attached Figure 4 For attachment Figure 1 Schematic diagram of the cross-sectional structure at CC in the middle.

[0028] Attached Figure 5 For attachment Figure 1 Schematic diagram of the cross-sectional structure at DD in the middle.

[0029] Attached Figure 6 For attachment Figure 1 Schematic diagram of the cross-sectional structure at EE in the middle.

[0030] Attached Figure 7 For attachment Figure 1 Schematic diagram of the enlarged structure at F in the middle.

[0031] Attached Figure 8 For attachment Figure 1 Schematic diagram of the enlarged structure at G in the middle.

[0032] The codes in the attached drawings are: 1 is a high-pressure cylinder, 2 is a low-pressure cylinder, 3 is an extrusion plunger, 4 is a booster piston, 5 is a high-pressure action chamber, 6 is a low-pressure action chamber, 7 is an elastic reset member, 8 is a limit ring, 9 is a sealing cap, 10 is a first sealing sleeve, 11 is a first outer ring platform, 12 is a first buffer pad, 13 is an oil injection hole, 14 is an oil injection plug, 15 is a connecting sleeve, 16 is a first step surface, 17 is a lower support ring, 18 is an upper support ring, 19 is a packing ring, 20 is a packing cap, 21 is The second step surface, 22 is the connecting hole, 23 is the first inner ring platform, 24 is the straightening cylinder, 25 is the injection pipe, 26 is the external drainage hole, 27 is the second outer ring platform, 28 is the first sealing member, 29 is the second sealing member, 30 is the internal drainage hole, 31 is the friction pin, 32 is the third outer ring platform, 33 is the friction sleeve, 34 is the compression spring, 35 is the conversion joint, 36 is the disassembly sleeve, 37 is the transition surface, 38 is the second buffer pad, 39 is the third seal, 40 is the third buffer pad, and 41 is the fourth seal. DETAILED DESCRIPTION

[0033] The present invention is not limited by the following embodiments, and specific implementation methods can be determined based on the technical solution of the present invention and actual conditions.

[0034] In the present invention, for the convenience of description, the relative position relationship of each component is described according to the attached Figure 1 The layout is described in detail, such as the positional relationship of front, back, top, bottom, left, right, etc., which is based on the attached manual. Figure 1 The layout direction is determined by the

[0035] The present invention will be further described below in conjunction with embodiments and drawings: Embodiment 1: As shown in the attached Figures 1 to 5 As shown in Figures 7 and 8, the device for repairing deformed casing in oil and gas field production wells comprises a high-pressure cylinder 1, a low-pressure cylinder 2, an extrusion plunger 3 and a boosting piston 4. The upper end of the high-pressure cylinder 1 is provided with a high-pressure action chamber 5 which opens upward and is larger at the upper end and smaller at the lower end. The upper end of the high-pressure cylinder 1 is sealed and fixedly installed with the low-pressure cylinder 2. The upper end of the low-pressure cylinder 2 is provided with a low-pressure action chamber 6 whose lower end is connected with the upper end of the high-pressure action chamber 5. A plurality of staggered and radially penetrating sliding holes are arranged at intervals from top to bottom on the outer side of the lower part of the high-pressure cylinder 1 corresponding to the small-diameter section of the high-pressure action chamber 5. A pair of extrusion plungers 3 are sealed and slidably installed in each sliding hole. A boosting piston 4 is sealed and slidably installed in the low-pressure action chamber 6, and each extrusion plunger 3 can extend outward after the lower end moves downward. An elastic reset member 7 that can move the boosting piston 4 upward is installed on the inner side of the lower part of the low-pressure action chamber 6.

[0036] When in use, after assembling the high-pressure cylinder 1 and the extrusion plunger 3, add hydraulic oil to the high-pressure action chamber 5 to reach the set value, connect the high-pressure cylinder 1 and the low-pressure cylinder 2, and then connect the low-pressure cylinder 2 to the pipe string and lower it into the target position in the casing, and then add power fluid into the pipe string, increase the pressure of the power fluid to the set value and maintain it for a certain time, the high-pressure power fluid acts on the booster piston 4, so that the booster piston 4 moves downward, after the booster piston 4 moves downward, the hydraulic oil acts on the extrusion plunger 3, and the extrusion plunger 3 extends outward to squeeze the deformed part in the casing, completing the repair of the deformed part of the casing, and then reduce the power fluid pressure, the booster piston 4 moves up and resets under the action of the elastic reset member 7, and at the same time, the liquid pressure in the casing acts on the end of the extrusion plunger 3, so that the extrusion plunger 3 is retracted, and the pipe string continues to move down to the next deformation part of the casing, and the above process is repeated to complete the repair work of the deformation part of the casing at the corresponding position, and the pipe string is lifted after the repair work is completed.

[0037] The present invention injects hydraulic oil into a closed high-pressure action chamber 5, injects power fluid through a pipe string and acts on a booster piston 4, and the booster piston 4 pressurizes the hydraulic oil in the high-pressure action chamber 5, thereby pushing the extrusion plunger 3 to extend outward. After the extrusion plunger 3 extends out, the deformed part of the casing is extruded and repaired. The present invention can also complete the repair of deformed casing in horizontal well sections, with a low drill sticking accident rate. At the same time, the casing can be repaired under pressure conditions, thereby improving the efficiency of casing repair.

[0038] Embodiment 2: As an optimization of the above embodiment, as shown in the attached Figures 1 to 5 As shown in Figures 7 and 8, the projections of the central axes of the plurality of sliding holes on the horizontal plane are uniformly spaced along the circumference, and an annular groove located on the inner wall of the high-pressure action chamber 5 is provided between the end faces of each pair of extrusion plungers 3 that are close to each other, and a limiting ring 8 is installed in each annular groove. The outer side of each extrusion plunger 3 is sealed with a sealing pressure cap 9 that is screwed to the corresponding position of the sliding hole, and the end of each sealing pressure cap 9 close to the high-pressure action chamber 5 is fixed with a first sealing sleeve 10 that is in sealing contact with the corresponding position of the sliding hole, and the outer side of the end of each extrusion plunger 3 close to the limiting ring 8 is fixed with a first outer ring platform 11 that can move axially in the first sealing sleeve 10.

[0039] According to the requirements, the number of sliding holes is 4, and the middle of each sliding hole is connected to the small diameter section of the high pressure chamber 5. The angle between the projections of the central axes of the four sliding holes on the horizontal plane is 45 degrees, so that the deformation parts of the sleeve in the circumferential direction can be repaired. The central axis of the annular groove is collinear with the central axis of the sliding hole, and is perpendicular to the central axis of the high pressure chamber 5. The limit ring 8 is an existing well-known elastic retaining ring. During use, by setting the limit ring 8, the extrusion plunger 3 can be limited when it is retracted into the sliding hole, which can ensure that the extension amount of the extrusion plunger 3 is consistent when it is extended again. When the paired extrusion plungers 3 are extended, they can interact with each other to repair the deformation of the sleeve, thereby improving the repair quality.

[0040] Embodiment 3: As an optimization of the above embodiment, as shown in the attached Figures 1 to 5 As shown in Figures 7 and 8, a first buffer pad 12 is installed in the first sealing sleeve 10 corresponding to the position between the first outer ring platform 11 and the sealing pressure cap 9, and an oil filling hole 13 connected to the lower end of the high-pressure action chamber 5 is provided at the lower end of the high-pressure cylinder 1, and an oil filling plug 14 is sealed and fixedly installed in the oil filling hole 13.

[0041] According to the requirements, the first buffer pad 12 is an existing well-known copper pad. During use, by setting the first buffer pad 12, when the extrusion plunger 3 is extended, it can drive the first outer ring platform 11 close to the first sealing sleeve 10, and finally the first buffer pad 12 is used to achieve the sealing between the first outer ring platform 11 and the first sealing sleeve 10, so as to prevent the end face of the first outer ring platform 11 close to the limit ring 8 from being subjected to high pressure, which makes the seal between the extrusion plunger 3 and the sealing pressure cap 9 fail, thereby improving the stability of the extrusion plunger 3 when it is extended outward after being subjected to high pressure.

[0042] Embodiment 4: As an optimization of the above embodiment, as shown in the attached Figure 1 , 8As shown, a connecting sleeve 15 is sealed and fixedly installed on the inner side of the upper end of the high-pressure cylinder 1, and a sealing sleeve is installed on the outer side of the lower part of the boosting piston 4. The upper outer side of the connecting sleeve 15 and the inner side of the lower end of the low-pressure cylinder 2 are fixedly installed together. The boosting piston 4 is T-shaped with a large upper part and a small lower part. The upper outer side of the boosting piston 4 is sealed and slidably installed on the upper inner side of the low-pressure cylinder 2. The lower inner side of the connecting sleeve 15 has a first step surface 16. The upper end of the first step surface 16 is spaced from bottom to top with a lower support ring 17 and an upper support ring 18 installed on the outer side of the lower part of the boosting piston 4. The lower support ring 17 and the upper support ring 18 are installed at intervals from bottom to top. A number of sealing packing rings 19 are stacked in sequence from bottom to top between the support rings 18, and the packing rings 19 are sealed and sleeved on the outer side of the lower part of the boosting piston 4. A tubular packing pressure cap 20 is fixedly installed on the inner side of the upper part of the connecting sleeve 15, and the lower end of which abuts against the upper support ring 18. The outer side of the upper part of the connecting sleeve 15 has a second step surface 21, and at least one connecting hole 22 connected inside and outside is distributed along the circumferential direction at intervals on the outer side of the lower part of the low-pressure cylinder 2 corresponding to the position above the second step surface 21. The elastic reset member 7 is sleeved on the inner side of the low-pressure cylinder 2 between the lower end surface of the large diameter section of the boosting piston 4 and the second step surface 21.

[0043] According to the requirements, the elastic reset member 7 is an existing well-known technology, such as a compression spring 34. During use, by setting the upper support ring 18 and the lower support ring 17, the packing ring 19 can be limited to prevent the packing ring 19 from being worn prematurely during the up and down movement of the booster piston 4, resulting in a lower sealing performance of the high-pressure action chamber 5. The booster piston 4 is T-shaped with a large upper part and a small lower part, and the pressure of the liquid in the injection tube 25 can be transferred to the pressure of the fluid in the high-pressure action chamber 5 through the booster piston 4, thereby increasing the pressure of the fluid in the high-pressure action chamber 5, thereby pushing the extrusion plunger 3 to extend and squeeze the deformed part of the sleeve, and quickly completing the repair work of the sleeve.

[0044] Embodiment 5: As an optimization of the above embodiment, as shown in the attached Figure 1 , 8 As shown, a first inner ring platform 23 whose lower end abuts against the upper end of the boosting piston 4 is fixed on the inner side of the upper part of the low-pressure cylinder 2, a straightening cylinder 24 whose upper end is located above the low-pressure cylinder 2 is sealed and fixed on the inner side of the upper end of the low-pressure cylinder 2, a liquid injection tube 25 whose upper end is located above the straightening cylinder 24 is installed and slidably installed in the straightening cylinder 24, at least one external liquid discharge hole 26 connected inside and outside is distributed at intervals along the circumferential direction on the outer side of the lower part of the liquid injection tube 25 corresponding to the position above the first inner ring platform 23, a second outer ring platform 27 whose upper end is spaced apart from the lower end of the straightening cylinder 24 is fixed on the outer side of the lower part of the liquid injection tube 25, at least one first sealing member 28 is provided between the outer side of the second outer ring platform 27 corresponding to the position above the external liquid discharge hole 26 and the inner side of the low-pressure cylinder 2 at an interval of up and down, at least one second sealing member 29 is provided between the inner side of the first inner ring platform 23 and the outer side of the lower end of the liquid injection tube 25 at an interval of up and down, and at least one internal liquid discharge hole 30 connected inside and outside is distributed at intervals along the circumferential direction on the outer side of the liquid injection tube 25 corresponding to the position above the second outer ring platform 27.

[0045] According to the requirements, the second sealing member 29 is an existing well-known O-ring. During use, the lower end of the first inner ring 23 abuts against the upper end of the booster piston 4, so that the elastic reset member 7 has a pre-compression amount. The elastic reset member 7 supports the booster piston 4 to prevent the booster piston 4 from moving downward under the action of gravity and acting on the high-pressure action chamber 5 during the casing lowering process, so that the extrusion plunger 3 extends outward and causes difficulty in entering the well. At the same time, after the casing deformation repair is completed, the elastic reset member 7 can cause the booster piston 4 to rise and then reset, so that the extrusion plunger 3 is retracted into place.

[0046] After entering the well and reaching the deformation part of the casing, the high-pressure cylinder 1 moves downward and encounters resistance, and the injection pipe 25 drives the second outer ring platform 27 to move downward. After the second outer ring platform 27 moves downward, it contacts the upper end of the first inner ring platform 23 and seals the external drainage hole 26. At this time, the pressure of the liquid in the injection pipe 25 can be increased to the set value, and then the pressure is stabilized for 2 minutes, and the deformation part of the casing can be repaired by squeezing the plunger 3.

[0047] When the pressure in the injection pipe 25 increases, the fluid in the injection pipe 25 flows through the inner drainage hole 30 into the annular cavity between the outside of the injection pipe 25, the inside of the low-pressure cylinder 2, the upper end of the second outer ring platform 27 and the lower end of the straightening cylinder 24, and when the pressure increases synchronously, pressure can be applied to the upper end surface of the second outer ring platform 27, thereby avoiding the pressure applied to the upper end of the booster piston 4 being reduced after the second outer ring platform 27 moves upward during the repair process, thereby improving the efficiency and quality of casing deformation repair.

[0048] When the deformation restoration and repair of the casing is completed, the pressure in the injection tube 25 is reduced, the tube string is lifted, and the second outer ring platform 27 is moved up so that the lower end of the injection tube 25 is connected with the casing through the external discharge hole 26. The fluid at the upper end of the booster piston 4 is injected into the casing after the elastic restoration member 7 is restored. The upper end surface of the booster piston 4 is balanced with the pressure in the casing, so that the liquid pressure in the casing acts on the end surface of the extrusion plunger 3, forcing the extrusion plunger 3 to be retracted, and the deformation part of the casing at the next depth or other circumferential surface at the same depth is continued to be repaired.

[0049] Embodiment 6: As an optimization of the above embodiment, as shown in the attached Figure 1 , 6As shown, a number of straightening grooves with openings facing outward are evenly spaced along the circumference on the outer side of the upper part of the straightening cylinder 24, and each straightening groove is fitted with a friction pin 31 of a cylindrical structure, and a third outer ring stage 32 fitted in the straightening groove is fixed to the outer side of the end of the friction pin 31 close to the inner wall of the straightening cylinder 24, and a friction sleeve 33 fitted on the outer side of the friction pin 31 is fixedly installed in the straightening groove, and a compression spring 34 is installed between the inner side of the friction pin 31 and the inner wall of the straightening groove to enable the end faces of the third outer ring stage 32 and the friction sleeve 33 to abut against each other. According to the requirements, the number of straightening grooves is three, the hardness of the friction pin 31 after heat treatment is not less than HRC50, and the inner side of the end face of the friction sleeve 33 away from the third outer ring stage 32 is a regular hexagon, so as to facilitate the disassembly and assembly of the friction sleeve 33. During use, through such an arrangement, the straightening cylinder 24 is lowered into the casing, and the friction pin 31 is extended outward under the action of the compression spring 34 and then abuts against the inner wall of the casing, so that the straightening cylinder 24 can be located in the center of the casing. When the paired extrusion plungers 3 are extended, the deformed part of the casing can be repaired to prevent the repair from failing to achieve the expected effect due to the different distances between the ends of the paired extrusion plungers 3 and the deformed part of the casing. At the same time, after the end of the friction pin 31 abuts against the inner wall of the casing, it can fix the low-pressure cylinder 2, making it convenient to move the injection pipe 25 up and down through the pipe string.

[0050] Embodiment 7: As an optimization of the above embodiment, as shown in the attached Figure 1 As shown, a conversion joint 35 is sealed and fixedly installed on the upper end of the centralizing cylinder 24. In the process of use, such an arrangement facilitates the connection between the centralizing cylinder 24 and the pipe string, and improves the efficiency of disassembly and assembly.

[0051] Embodiment 8: As an optimization of the above embodiment, as shown in the attached Figure 1 , 6 As shown, the end face of the friction pin 31 away from the straightening cylinder 24 is spherical. In use, such a configuration can make the friction pin 31 move up and down in the casing more smoothly, preventing jamming from affecting the high-pressure cylinder 1 moving toward the deformation of the casing, and reducing the failure rate.

[0052] Embodiment 9: As an optimization of the above embodiment, as shown in the attached Figures 1 to 5 As shown, the end face of the sealing pressure cap 9 away from the limiting ring 8 is fixed with a disassembly sleeve 36 which is sleeved on the outside of the extrusion plunger 3, and the outer contour surface of the disassembly sleeve 36 is hexagonal. According to the requirements, the outer contour surface of the disassembly sleeve 36 is a regular hexagon. During use, such a setting facilitates the installation of the disassembly sleeve 36, and at the same time, it is also convenient to adjust the distance between each pair of extrusion plungers 3 and the end face of the limiting ring 8, so that the extension amount of each pair of extrusion plungers 3 is consistent, avoiding the high-pressure cylinder 1 from tilting due to different extension amounts, which affects the repair efficiency of the deformation of the sleeve.

[0053] Embodiment 10: As an optimization of the above embodiment, as shown in the attached Figure 1As shown, a conical transition surface 37 with a larger top and a smaller bottom is formed between the large diameter section and the small diameter section of the high pressure chamber 5. In use, such a setting can ensure the stability of the fluid flow in the high pressure chamber 5, and prevent the high pressure cylinder 1 from vibrating due to sudden pressure changes, which affects the stability of the connection.

[0054] Embodiment 11: As an optimization of the above embodiment, as shown in the attached Figures 1 to 5 As shown in FIG. 7 , a second buffer pad 38 and a third sealing member 39 are sequentially arranged between the end of the first sealing sleeve 10 and the inner side of the sliding hole from the outside to the inside.

[0055] According to the requirements, the outer side of the first sealing sleeve 10 and the inner side of the sliding hole are threadedly connected, the third sealing member 39 is an existing well-known O-ring, and the second buffer pad 38 is an existing well-known copper pad. During use, the third sealing member 39 can improve the sealing performance between the first sealing sleeve 10 and the sliding hole, prevent the radial movement failure of the extrusion plunger 3 after the pressure in the high-pressure action chamber 5 is reduced, and reduce the efficiency of casing repair. By providing the buffer pad, the third sealing member 39 can be protected, preventing the third sealing member 39 from failing when subjected to high pressure, and extending the service life of the third sealing member 39.

[0056] Embodiment 12: As an optimization of the above embodiment, as shown in the attached Figures 1 to 5 As shown in Figures 7 and 8, the end surface of the extrusion plunger 3 away from the limiting ring 8 is in a spherical crown shape.

[0057] According to the requirements, the hardness of the spherical crown end of the extrusion plunger 3 after heat treatment is HRC50 to HRC55, so as to facilitate the repair of the sleeve. In the process of use, through such a setting, it is convenient for the extrusion plunger 35 to move up and down in the sleeve, reduce the friction force when the extrusion plunger 35 moves up and down, and improve the smoothness of the device in the sleeve. At the same time, when the extrusion plunger 3 is extended, it can move downward after extruding and repairing the sleeve deformation at the corresponding position, and then the extrusion plunger 3 staggered above it extrudes and repairs the sleeve deformation, so that the deformed inner wall of the sleeve at different positions can be repaired.

[0058] Embodiment 13: As an optimization of the above embodiment, as shown in the attached Figure 1 , 7 As shown, a chamfered structure is provided on the outer side of the lower end of the high-pressure cylinder 1. In the process of use, such a configuration can prevent the high-pressure cylinder 1 from colliding with the deformation of the casing when it is lowered into the casing, thereby preventing the deformation from further increasing.

[0059] Embodiment 14: As an optimization of the above embodiment, as shown in the attached Figure 1 , 7As shown, a third buffer pad 40 and a fourth seal 41 are sequentially arranged between the outer side of the upper part of the oil filling plug 14 and the inner side of the oil filling hole 13 from the outside to the inside. According to the requirements, the outer side of the oil filling plug 14 and the inner side of the oil filling hole 13 are threadedly connected, the fourth seal 41 is an existing well-known O-ring, the third buffer pad 40 is an existing well-known copper pad, and two O-rings are arranged at intervals above and below the outer side of the upper part of the oil filling plug 14 and the inner side of the oil filling hole 13 corresponding to the position above the third buffer pad 40. During use, by arranging the third buffer pad 40, the fourth seal 41 can be protected to prevent the high-pressure fluid in the sleeve and the high-pressure action chamber 5 from affecting the fourth seal 41, making the fourth seal 41 ineffective, and the sealing between the oil filling plug 14 and the oil filling hole 13 can also be improved.

[0060] Embodiment 15: As an optimization of the above embodiment, as shown in the attached Figures 1 to 8 As shown, the deformed casing repair method is characterized by comprising the following steps: The first step is to assemble a device for repairing a deformed casing in a production well of an oil and gas field, invert the device for repairing a deformed casing in a production well of an oil and gas field, remove the oil injection plug 14, extract the extrusion plunger 3, and inject hydraulic oil into the high-pressure cavity through the oil injection hole 13. The liquid level of the hydraulic oil rises to the oil injection hole 13 when all the extrusion plungers 3 are retracted, and then the oil injection plug 14 is sealed and fixedly installed in the oil injection hole 13, and the device for repairing a deformed casing in a production well of an oil and gas field is reversed and assembled, and the conversion joint 35 is connected to the pipe string; The second step is to lower the high-pressure cylinder 1 into the deformation position of the casing; The third step is to inject power fluid into the pipe string, and the power fluid flows into the injection pipe 25 through the conversion joint 35; The fourth step is to increase the power fluid pressure and stabilize it for a certain period of time; Step 5: Stop injecting the power fluid and lift the pipe string; Step 6: Repeat steps 2 to 5 until the repair of the deformed casing section is completed.

[0061] When in use, first assemble the device for repairing the deformed casing in the oil and gas field production well in sequence, then invert the device for repairing the deformed casing in the oil and gas field production well, fix the lower end of the high-pressure cylinder 1 upward firmly, and keep the high-pressure cylinder 1 vertical, pull out the four pairs of extrusion plungers 3, so that the extrusion plungers 3 extend outward to the maximum position, remove the oil filling plug 14, and inject a certain amount of hydraulic oil, such as 91 ml, into the high-pressure action chamber 5 from the oil filling hole 13, and then retract the extrusion plungers 3 from bottom to top in sequence, so that the extrusion plungers 3 are retracted inward to the initial position, and the liquid is observed at this time. The liquid level position of the hydraulic oil is determined. If the liquid level of the hydraulic oil does not rise to the oil filling hole 13, continue to add hydraulic oil until the liquid level of the hydraulic oil is located in the oil filling hole 13. If the distance between the liquid level of the hydraulic oil and the lower end of the high-pressure action chamber 5 is greater than 5 mm, use a liquid suction dropper to extract excess hydraulic oil so that the distance between the liquid level of the hydraulic oil and the lower end of the high-pressure action chamber 5 is 5 mm. Then, the oil filling plug 14 is sealed and screwed into the oil filling hole 13. The device for repairing deformed casing in oil and gas field production wells is turned over and assembled. According to needs, the conversion joint 35 is connected to the continuous oil pipe or the ordinary oil pipe.

[0062] Then connect the weight meter connected to the external operation setting to the device, and then lower the device into the wellbore. Use the weight meter on the operation equipment to judge whether the casing in the wellbore where the device is located is deformed. If the value displayed on the weight meter suddenly decreases, it means that the device is stuck when it is lowered into the wellbore, that is, the casing is deformed here. After the high-pressure cylinder 1 is blocked, the injection pipe 25 continues to move downward, and the injection pipe 25 drives the second outer ring platform 27 to move downward. After the second outer ring platform 27 moves downward and contacts with the upper end of the first inner ring platform 23, it seals the external drainage hole 26, and injects power fluid into the power fluid injection device through an external continuous oil pipe or an ordinary oil pipe. When the power fluid is injected, the power fluid injection pressure can be controlled according to the well depth position of the device in the wellbore, the pressure in the wellbore, and the density of the power fluid, so that the pressure in the high-pressure action chamber 5 does not exceed 400MPa. The power fluid acts on the upper end of the booster piston 4 through the injection pipe 25. After the power fluid increases to the set value, the pressure is stabilized for 2 minutes. During this process, the power fluid The power fluid acts on the upper end surface of the booster piston 4, so that the booster piston 4 moves downward to the large diameter section of the high-pressure action chamber 5. The lower end of the booster piston 4 pressurizes the hydraulic oil in the high-pressure action chamber 5, thereby pushing the extrusion plunger 3 to extend outward and repairing the deformed part of the sleeve. After the pressure stabilization is completed, the injection of the power fluid is stopped, and the injection pipe 25 is lifted. After the second outer ring platform 27 moves up, the lower end of the injection pipe 25 and the sleeve are connected through the external discharge hole 26. The power fluid at the upper end of the booster piston 4 is injected into the sleeve after the elastic reset member 7 is reset. At this time, the booster piston 4 loses pressure, and the original liquid in the sleeve acts on the outer end surface of the extrusion plunger 3, forcing the extrusion plunger 3 to retract, and then continue to lower the device into the sleeve. If it passes smoothly, it means that the deformation part of the sleeve here has been repaired. If the lowering of the device encounters resistance, the device is lifted for a short distance and then lowered, and then the power fluid is injected into the device to the control pressure. Repeat the above process to complete the repair of the deformed sleeve.

[0063] The above technical features constitute the embodiments of the present invention, which have strong adaptability and implementation effect. Non-essential technical features can be added or reduced according to actual needs to meet the requirements of different situations.

Claims

1. A device for repairing deformed casing in a production well of an oil and gas field, characterized in that The invention comprises a high-pressure cylinder, a low-pressure cylinder, an extrusion plunger and a boosting piston. A high-pressure action chamber with an opening upward and a larger upper part and a smaller lower part is provided at the upper end of the high-pressure cylinder. A low-pressure cylinder is sealed and fixedly installed at the upper end of the high-pressure cylinder. A low-pressure action chamber whose lower end is connected with the upper end of the high-pressure action chamber is provided at the upper end of the low-pressure cylinder. A plurality of staggered and radially penetrating sliding holes are provided at intervals from top to bottom on the outer side of the lower part of the high-pressure cylinder corresponding to the position of the small-diameter section of the high-pressure action chamber. A pair of extrusion plungers are sealed and slidably installed in each sliding hole. A boosting piston is sealed and slidably installed in the low-pressure action chamber. When the lower end moves downward, each extrusion plunger can extend outward. An elastic reset part that can move the boosting piston upward is installed on the inner side of the lower part of the low-pressure action chamber.

2. The device for repairing deformed casing in oil and gas field production wells according to claim 1 is characterized in that The projections of the central axes of the plurality of sliding holes on the horizontal plane are evenly spaced along the circumference, and an annular groove located on the inner wall of the high-pressure action chamber is provided between the end faces of each pair of extrusion plungers that are close to each other, and a limiting ring is installed in each annular groove. The outer side of each extrusion plunger is sealed with a sealing pressure cap that is screwed to the corresponding position of the sliding hole, and the end of each sealing pressure cap close to the high-pressure action chamber is fixed with a first sealing sleeve that is in sealing contact with the corresponding position of the sliding hole, and the outer side of the end of each extrusion plunger close to the limiting ring is fixed with a first outer ring platform that can move axially in the first sealing sleeve.

3. The device for repairing deformed casing in oil and gas field production wells according to claim 2 is characterized in that A first buffer pad is sleeved in the first sealing sleeve corresponding to the position between the first outer ring platform and the sealing pressure cap. The lower end of the high-pressure cylinder is provided with an oil filling hole connected to the lower end of the high-pressure action chamber. An oil filling plug is sealed and fixedly installed in the oil filling hole.

4. The device for repairing deformed casing in a production well of an oil and gas field according to claim 1, 2 or 3, characterized in that The cam is secured to the inner side of the body with a seal which is fixedly mounted on the upper side of the high-pressure cylinder and is wrapped around the outside of the lower portion of the booster piston. The cam is secured to the inner side of the body with a seal which is fixedly mounted on the upper side of the high-pressure cylinder and is wrapped around the outside of the lower portion of the booster piston. The cam is secured to the inner side of the body with a seal which is fixedly mounted on the upper side of the low-pressure cylinder and is wrapped around the inside of the upper portion of the low-pressure cylinder.

5. The device for repairing deformed casing in oil and gas field production wells according to claim 4 is characterized in that A first inner ring platform is fixed on the inner side of the upper part of the low-pressure cylinder, and its lower end abuts against the upper end of the boosting piston. A straightening cylinder with its upper end located above the low-pressure cylinder is sealed and fixed on the inner side of the upper end of the low-pressure cylinder. A liquid injection tube with its upper end located above the straightening cylinder is sealed and slidably installed in the straightening cylinder. At least one external liquid discharge hole connected inside and outside is circumferentially spaced apart on the outer side of the lower part of the liquid injection tube corresponding to the position above the first inner ring platform. A second outer ring platform is fixed on the outer side of the lower part of the liquid injection tube, and an upper end thereof is spaced apart from the lower end of the straightening cylinder. At least one first sealing member is spaced apart from the upper and lower sides between the outer side of the second outer ring platform corresponding to the position above the external liquid discharge hole and the inner side of the low-pressure cylinder. At least one second sealing member is spaced apart from the upper and lower sides between the inner side of the first inner ring platform and the outer side of the lower end of the liquid injection tube. At least one internal liquid discharge hole connected inside and outside is spaced apart from the circumferential direction on the outer side of the liquid injection tube corresponding to the position above the second outer ring platform.

6. The device for repairing deformed casing in oil and gas field production wells according to claim 5 is characterized in that A number of outward-opening straightening grooves are evenly distributed along the circumference on the outer side of the upper part of the straightening cylinder, each of which is fitted with a friction pin of a cylindrical structure, a third outer ring stage fitted in the straightening groove is fixed to the outer side of the end of the friction pin close to the inner wall of the straightening cylinder, a friction sleeve fitted on the outer side of the friction pin is fixed in the straightening groove, and a compression spring is installed between the inner side of the friction pin and the inner wall of the straightening groove, which can make the end faces of the third outer ring stage and the friction sleeve abut against each other.

7. The device for repairing deformed casing in oil and gas field production wells according to claim 6 is characterized in that A conversion joint is sealed and fixedly installed on the upper end of the straightening cylinder; or / and, the end surface of the friction pin away from the straightening cylinder is in a spherical crown shape.

8. The device for repairing a deformed casing in a production well of an oil and gas field according to claim 3, 5, 6 or 7, characterized in that A disassembly sleeve which is mounted on the outside of the extrusion plunger is fixed to the end face of the sealing pressure cap away from the limiting ring, and the outer contour of the disassembly sleeve is hexagonal; or / and, a conical transition surface which is larger at the top and smaller at the bottom is formed between the large diameter section and the small diameter section of the high-pressure action chamber; or / and, a second buffer pad and a third seal are arranged in sequence from the outside to the inside between the end of the first sealing sleeve and the inner side of the sliding hole; or / and, the end face of the extrusion plunger away from the limiting ring is spherical; or / and, a chamfered structure is provided on the outer side of the lower end of the high-pressure cylinder; or / and, a third buffer pad and a fourth seal are arranged in sequence from the outside to the inside between the outer side of the upper part of the oil filling plug and the inner side of the oil filling hole.

9. The device for repairing deformed casing in a production well of an oil and gas field according to claim 4, characterized in that A disassembly sleeve which is mounted on the outside of the extrusion plunger is fixed to the end face of the sealing pressure cap away from the limiting ring, and the outer contour of the disassembly sleeve is hexagonal; or / and, a conical transition surface which is larger at the top and smaller at the bottom is formed between the large diameter section and the small diameter section of the high-pressure action chamber; or / and, a second buffer pad and a third seal are arranged in sequence from the outside to the inside between the end of the first sealing sleeve and the inner side of the sliding hole; or / and, the end face of the extrusion plunger away from the limiting ring is spherical; or / and, a chamfered structure is provided on the outer side of the lower end of the high-pressure cylinder; or / and, a third buffer pad and a fourth seal are arranged in sequence from the outside to the inside between the outer side of the upper part of the oil filling plug and the inner side of the oil filling hole.

10. A method for repairing a deformed casing in a production well of an oil and gas field using the device for repairing a deformed casing in an oil and gas field according to any one of claims 1 to 9, characterized in that The following steps are involved: The first step is to assemble a device for repairing a deformed casing in a production well of an oil and gas field, invert the device for repairing a deformed casing in a production well of an oil and gas field, remove the oil injection plug, extract the extrusion plunger, and inject hydraulic oil into the high-pressure cavity through the oil injection hole. The liquid level of the hydraulic oil rises to the oil injection hole when all the extrusion plungers are retracted, and then the oil injection plug is sealed and fixedly installed in the oil injection hole, and the device for repairing a deformed casing in a production well of an oil and gas field is assembled and turned over, and the conversion joint is connected to the pipe string; The second step is to lower the high-pressure cylinder into the deformation position of the casing; The third step is to inject power fluid into the pipe string, and the power fluid flows into the injection pipe through the conversion joint; The fourth step is to increase the power fluid pressure and stabilize it for a certain period of time; Step 5: Stop injecting the power fluid and lift the pipe string; Step 6: Repeat steps 2 to 5 until the repair of the deformed casing section is completed.

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