Gas well full life cycle well completion gas production device and process method

Abstract

The invention belongs to the technical field of gas field well completion, and particularly relates to a gas well full life cycle well completion gas production device and process method.The device comprises an upper connector, a lower connector, a first outer barrel, a first connecting pipe, a second outer barrel, a second connecting pipe, a third outer barrel and a gas nozzle base which are sequentially connected through screw threads, and O-shaped ring seals are arranged at the screw thread connecting positions; a first communicating structure is arranged on the inner wall of the first outer barrel and used for communicating or separating the inner space and the outer space of the first outer barrel according to the life cycle of a gas well; a second communicating structure is arranged on the inner wall of the second outer barrel and used for communicating or separating the inner space and the outer space of the second outer barrel according to the life cycle of the gas well. The first communicating structure and the second communicating structure are arranged, so that gas production of a gas well from initial well completion to waste full-life-cycle well completion is achieved, the running and fishing operation cost of a preset flow controller and a slip flow controller is saved, and underground accidents caused by running and fishing failures of the two flow controllers are avoided.

Description

Technical Field

[0001] The present invention belongs to the technical field of gas field completion, and in particular relates to a gas well completion and gas production device and a process method for the whole life cycle of a gas well. Background Art

[0002] The gas wells in tight gas fields have a short high-pressure period and a long low-pressure period. 75% of the cumulative gas production is produced during the low-pressure period. Therefore, it is particularly important to select gas production technology suitable for the full life cycle of low-pressure and low-production gas wells. The 60.3mm Ф tubing completion method widely used in the early stage, although the gas production process is mature, the main process measures are implemented in stages, with poor results and high costs. In recent years, the 50.8mm Ф continuous tubing completion technology has been initially formed in China, and has become the main completion technology for tight gas wells, with a total of more than 550 wells.

[0003] At present, there is a contradiction between fracturing fluid return and downhole throttling during the on-site application of coiled tubing completion in tight gas wells. Specifically, on the one hand, before the gas well is completed by coiled tubing, only the Ф114.3mm large casing is used, which is insufficient to completely return the fracturing fluid. After completion, a small-diameter Ф50.8mm coiled tubing is needed to return the fracturing fluid. On the other hand, since the ground gas transmission pipeline network generally adopts medium and low pressure gathering and transportation, the downhole throttling process must be used to reduce the wellhead oil pressure during the production of gas wells completed by Ф50.8mm coiled tubing. The outer diameter of the throttling nozzle used in the downhole throttling process is only 3-8mm, which seriously affects the return of fracturing fluid. There are two current practices: one is to install a pre-set choke mandrel at the end of the coiled tubing when completing the well. After the gas well fracturing fluid is completely returned, the choke core (including the choke nozzle) is placed through wireline operation. Once there is sand and scale accumulation in the mandrel, the choke core cannot be set; the other is to place the slip-type downhole choke to the middle of the coiled tubing through wireline operation. Since the maximum outer diameter of the slip-type downhole choke is only 38mm, the overall strength of this tool is low, it is easy to break and difficult to salvage. If the choke cannot be salvaged, various drainage and gas production processes such as plunger gas lift cannot be implemented subsequently, which seriously affects the production of the gas well. Therefore, a new completion process and tool are urgently needed. By pre-setting a special tool at the tail end of the coiled tubing during well completion, the coiled tubing can be sealed when under pressure - full-bore coiled tubing returns fracturing fluid - downhole throttling production - full-bore velocity string drainage and gas production - plunger gas lift drainage and gas production until the gas well is scrapped. Summary of the invention

[0004] In order to overcome the defects of the above-mentioned prior art, the purpose of the present invention is to provide a gas well completion and gas production device and process method for the whole life cycle of the gas well, and the first stage is realized after the completion of the well: the continuous oil pipe is sealed when the pipe is lowered under pressure to prevent the production of natural gas in the wellbore; the second stage: the full-bore continuous oil pipe and the side port return the fracturing fluid to improve the return rate of the fracturing fluid and ensure the smooth production of the gas well; the third stage: downhole throttling production to prevent the freezing of hydrate production in the wellbore and reduce the wellhead oil pressure to the pressure of the gathering and transportation system; the fourth stage: the full-bore continuous oil pipe and the side port implement the speed string water drainage gas production production to ensure the stable liquid-carrying production of the gas well for a period of time; the fifth stage: the plunger gas lift is used to discharge the wellbore accumulated liquid in the fourth stage, and then the plunger gas lift production is continued until the gas well is scrapped.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A gas well full life cycle completion and gas production device, comprising an upper joint, a lower joint, a first outer tube, a first connecting pipe, a second outer tube, a second connecting pipe, a third outer tube and a gas nozzle seat connected in sequence by threads, and a sealing structure is provided at the threaded connection.

[0007] The inner wall of the first outer cylinder is provided with a first communication structure, and the first communication structure is used to connect or separate the inner and outer spaces of the first outer cylinder according to the life cycle of the gas well;

[0008] The inner wall of the second outer cylinder is provided with a second connecting structure, and the second connecting structure is used to connect or separate the inner and outer spaces of the second outer cylinder according to the life cycle of the gas well.

[0009] Optionally, an air nozzle is inserted into the air nozzle seat, one end of the air nozzle is inserted into the air nozzle seat, and a pressure cap is provided at the other end. The pressure cap is connected to the air nozzle seat by a thread. A sand cover is provided on the outside of the pressure cap, and the sand cover is connected to the air nozzle seat by a thread. A sealing structure is provided at the threaded connection.

[0010] Optionally, the inner cavity of the upper joint is provided with a conical slip and a conical sleeve.

[0011] Optionally, the first connecting structure includes a first shear pin, an upper sleeve and a first outlet, the inner wall of the first outer cylinder is fixedly connected to the upper sleeve by the first shear pin, the cylinder wall of the first outer cylinder is provided with a first outlet, the upper sleeve covers the first outlet, and the flow area of ​​the first outlet is not less than the flow area of ​​the continuous oil pipe.

[0012] Optionally, the second connecting structure includes a second shear pin, a lower sleeve, a second outlet and a plugging head. The inner wall of the second outer cylinder is fixedly connected to the outer wall of the lower sleeve by the second shear pin. The second outer cylinder is provided with a second outlet on the wall of the lower sleeve. A through hole is opened at a position corresponding to the second outlet. A plugging head is provided in the lower sleeve. One end of the plugging head covers the through hole. A limiting block is provided at the other end of the plugging head and is connected to the second connecting pipe by a third shear pin. A limiting groove is provided at one end of the limiting block of the second connecting pipe.

[0013] Optionally, the second outer tube is a reducing tube, and the inner diameter of one end of the second outer tube close to the first connecting tube is smaller than the inner diameter of one end of the second outer tube close to the second connecting tube;

[0014] The lower sliding sleeve is located at one end of the second outer tube close to the first connecting tube, and a check spring is provided at one end of the lower sliding sleeve close to the second connecting tube. The check spring is located between the second outer tube and the lower sliding sleeve, and one end of the check spring is in contact with the inner wall of the second outer tube. The other end of the check spring is fixedly connected to the lower sliding sleeve by a pin, and the check spring is in a compressed state.

[0015] Optionally, a check assembly is provided at one end of the second connecting tube close to the third outer tube, the check assembly is in a compressed state, one end of the check assembly is fixedly connected to the inner wall of the second connecting tube by a pin, and the other end of the check assembly is fixed by a soluble material.

[0016] Optionally, the gas well full life cycle completion and gas production device also includes soluble balls, steel balls and plungers.

[0017] The outer diameter of the soluble ball is larger than the inner diameter of the lower sleeve and smaller than the inner diameters of the first connecting pipe and the second outer tube. The soluble ball gradually dissolves when it encounters fracturing fluid or water and can be completely dissolved within 30 days.

[0018] The outer diameter of the steel ball is larger than the inner diameter of the upper sliding sleeve and smaller than the inner diameter of the first outer cylinder;

[0019] The size of the plunger is adapted to the inner diameter of the upper connector;

[0020] The soluble ball, steel ball and plunger are used to be put into the gas production device from the upper joint in sequence according to the life cycle of the gas well.

[0021] Optionally, the strengths of the third shear nail, the second shear nail and the first shear nail are increased in sequence.

[0022] On the other hand, the present invention discloses a gas well completion and gas production process during the whole life cycle, which uses the above-mentioned device to complete the well and produce gas, including:

[0023] S1. Insert the coiled tubing into the inner cavity of the upper joint, conical slip, cone sleeve and lower joint until it is locked, lower the coiled tubing and gas production device into the casing to the preset depth, and complete the coiled tubing hanging, pipe cutting, sealing and gas wellhead installation in sequence;

[0024] S2. Inject nitrogen into the coiled tubing and gradually increase the pressure, so that the third shear nail is cut off, the plugging head falls into the sand cover, the second outlet is opened, and the fracturing fluid is returned;

[0025] S3. Throw a soluble ball into the coiled tubing to the lower sleeve, inject nitrogen into the coiled tubing and gradually pressurize it, push the soluble ball and the lower sleeve to move together, thereby shearing the second shear nail, until the lower sleeve moves to the connecting pipe, close the second outlet, and the lower sleeve moves down to the expanded diameter of the second outer tube. The compressed check spring stretches to prevent the lower sleeve from moving back to its original position. The soluble ball is completely dissolved after contacting the fracturing fluid or water, and the downhole choke production begins;

[0026] S4. When the gas well is opened for production, the soluble material at one end of the check assembly dissolves when it encounters water in the wellbore, and the compressed check assembly radially extends, thereby preventing the plugging head from returning to the initial position and blocking the coiled tubing;

[0027] S5. When the gas well adopts downhole throttling production and liquid begins to accumulate in the wellbore, a steel ball is thrown into the coiled tubing to the upper sleeve, and nitrogen is injected into the coiled tubing and gradually pressurized to push the steel ball and the upper sleeve to move together, thereby shearing off the first shear pin until the upper sleeve moves to the connecting pipe, the first outlet is opened, and the coiled tubing is used as a velocity string to discharge the liquid accumulated in the wellbore;

[0028] S6. When liquid accumulation appears in the wellbore of the gas well again, a plunger is thrown into the coiled tubing to the upper joint, and the gas production device is used as a receiver of the plunger. The plunger is used to drain water and produce gas until the gas well reaches the abandonment pressure.

[0029] Technical effects and advantages of the present invention:

[0030] The present invention realizes pressure-carrying pipe, fracturing fluid return, downhole throttling production, velocity string water drainage and gas production, and plunger gas lift water drainage and gas production in sequence, covering the entire life cycle of the gas well from initial completion to abandonment, ensuring the orderly connection of various water drainage and gas production measures, saving the cost of launching and salvaging preset throttles and slip throttles, and avoiding downhole accidents caused by failure of launching and salvaging these two types of throttles.

[0031] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is a structural schematic diagram of a first connecting structure of the present invention;

[0033] Figure 2is a structural schematic diagram of a second connecting structure of the present invention;

[0034] Figure 3 It is a schematic diagram of the device of the present invention being connected to the coiled tubing and then being lowered under pressure;

[0035] Figure 4 A schematic diagram of the device of the present invention for removing the plug and secondary return of fracturing fluid;

[0036] Figure 5 This is a schematic diagram of the device of the present invention in which soluble balls are put into the device to close the fracturing sleeve;

[0037] Figure 6 It is a schematic diagram of downhole throttling production after the soluble balls of the device of the present invention are dissolved;

[0038] Figure 7 It is a schematic diagram of the device of the present invention when a steel ball is put into the device to open the drainage and gas recovery sliding sleeve velocity column for production;

[0039] Figure 8 This is a schematic diagram of the present invention when the plunger is deployed to drain water and produce gas.

[0040] : 1. upper joint; 2. conical slip; 3. conical sleeve; 4. lower joint; 5. first shear pin; 6. first outlet; 7. upper sliding sleeve; 8. first outer tube; 9. first connecting pipe; 10. second outer tube; 11. lower sliding sleeve; 12. second shear pin; 13. second outlet; 14. check spring; 15. plugging head; 16. third shear pin; 17. second connecting pipe; 18. check assembly; 19. third outer tube; 20. air nozzle seat; 21. air nozzle; 22. pressure cap; 23. sand cover; 24. soluble ball; 25. steel ball; 26. plunger. DETAILED DESCRIPTION

[0041] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] In order to overcome the defects of the above-mentioned prior art, the present invention provides a gas well full life cycle completion and gas production device, including an upper joint 1, a lower joint 4, a first outer tube 8, a first connecting pipe 9, a second outer tube 10, a second connecting pipe 17, a third outer tube 19 and a gas nozzle seat 20 connected in sequence by threads, and the threaded connections are all provided with sealing structures, such as O-ring seals, and the inner wall of the first outer tube 8 is provided with a first connecting structure, and the first connecting structure is used to connect or separate the inner and outer spaces of the first outer tube 8 according to the life cycle of the gas well; the inner wall of the second outer tube 10 is provided with a second connecting structure, and the second connecting structure is used to connect or separate the inner and outer spaces of the second outer tube 10 according to the life cycle of the gas well.

[0043] Optionally, an air nozzle 21 is inserted into the air nozzle seat 20, one end of the air nozzle 21 is inserted into the air nozzle seat 20, and a pressure cap 22 is provided at the other end. The pressure cap 22 is connected to the air nozzle seat 20 by a thread. A sand cover 23 is provided on the outer side of the pressure cap 22. The sand cover 23 is connected to the air nozzle seat 20 by a thread, and a sealing structure, such as an O-ring seal, is provided at the threaded connection.

[0044] Optionally, the inner cavity of the upper joint 1 is provided with a conical slip 2 and a conical sleeve 3.

[0045] Optional, Figure 1 is a schematic diagram of the structure of the first connected structure, such as Figure 1 As shown, the first connecting structure includes a first shear nail 5, an upper sleeve 7 and a first outlet 6. The inner wall of the first outer cylinder 8 is fixedly connected to the upper sleeve 7 through the first shear nail 5. The cylinder wall of the first outer cylinder 8 is provided with the first outlet 6. The upper sleeve 7 covers the first outlet 6. The flow area of ​​the first outlet 6 is not less than the flow area of ​​the coiled tubing.

[0046] Optional, Figure 2 is a schematic diagram of the structure of the second connected structure, such as Figure 2 As shown, the second connecting structure includes a second shear nail 12, a lower sleeve 11, a second outlet 13 and a plugging head 15. The inner wall of the second outer cylinder 10 is fixedly connected to the outer wall of the lower sleeve 11 by the second shear nail 12. The cylinder wall of the second outer cylinder 10 is provided with a second outlet 13. The lower sleeve 11 is provided with a through hole at a position corresponding to the second outlet 13. The lower sleeve 11 is provided with a plugging head 15. One end of the plugging head 15 covers the through hole. The other end of the plugging head 15 is provided with a limiting block and is connected to the second connecting pipe 17 by a third shear nail 16. A limiting groove is provided at one end of the second connecting pipe 17 corresponding to the limiting block.

[0047] Optionally, the second outer tube 10 is a reducing tube, and the inner diameter of the end of the second outer tube 10 close to the first connecting tube 9 is smaller than the inner diameter of the end close to the second connecting tube 17;

[0048] The lower sleeve 11 is located at one end of the second outer tube 10 close to the first connecting tube 9, and a check spring 14 is provided at one end of the lower sleeve 11 close to the second connecting tube 17. The check spring 14 is located between the second outer tube 10 and the lower sleeve 11. One end of the check spring 14 is in contact with the inner wall of the second outer tube 10, and the other end of the check spring 14 is fixedly connected to the lower sleeve 11 by a pin, and the check spring 14 is in a compressed state.

[0049] Optionally, a check assembly 18 is provided at one end of the second connecting tube 17 close to the third outer tube 19, and the check assembly 18 is in a compressed state. One end of the check assembly 18 is fixedly connected to the inner wall of the second connecting tube 17 by a pin, and the other end of the check assembly 18 is fixed by a soluble material.

[0050] Optionally, the device further comprises a soluble ball 24, a steel ball 25 and a plunger 26, wherein the outer diameter of the soluble ball 24 is larger than the inner diameter of the lower sleeve 11 and smaller than the inner diameters of the first connecting tube 9 and the second outer tube 10, and the soluble ball 24 gradually dissolves when it encounters fracturing fluid or water, and can be completely dissolved within 30 days;

[0051] The outer diameter of the steel ball 25 is larger than the inner diameter of the upper sliding sleeve 7 and smaller than the inner diameter of the first outer cylinder 8;

[0052] The size of the plunger 26 is adapted to the inner diameter of the upper connector 1;

[0053] The soluble ball 24, the steel ball 25 and the plunger 26 are used to be put into the gas production device from the upper joint 1 in sequence according to the life cycle of the gas well.

[0054] Optionally, the strengths of the third shear nail 16, the second shear nail 12 and the first shear nail 5 are enhanced in sequence to ensure that the shear nails are sheared in sequence when gas injection and ball injection are performed inside the coiled tubing.

[0055] On the other hand, the present invention also discloses a gas well completion and gas production process in the whole life cycle, which uses the above-mentioned device to complete the well and produce gas, including:

[0056] S1. Insert the coiled tubing into the inner cavity of the upper joint 1, the conical slip 2, the cone sleeve 3 and the lower joint 4 until it is locked, lower the coiled tubing and the gas production device into the casing to the preset depth, and complete the coiled tubing hanging, pipe cutting, sealing and gas wellhead installation in sequence;

[0057] S2. Nitrogen is injected into the coiled tubing and gradually pressurized, so that the third shear nail 16 is sheared off, the plug 15 falls into the sand cover 23, the second outlet 13 is opened, and the fracturing fluid is returned;

[0058] S3. Throw a soluble ball 24 into the coiled tubing to the lower sleeve 11, inject nitrogen into the coiled tubing and gradually pressurize it, push the soluble ball 24 and the lower sleeve 11 to move together, thereby shearing the second shear nail 12, until the lower sleeve 11 moves to the connecting pipe 17, close the second outlet 13, and the lower sleeve 11 moves down to the expanded diameter of the second outer cylinder 10. The check spring 14 in the compressed state stretches, thereby preventing the lower sleeve 11 from moving up to its original position. The soluble ball 24 is completely dissolved after contacting the fracturing fluid or water, and the downhole choke production begins;

[0059] S4. When the gas well is opened for production, the soluble material at one end of the check assembly 18 dissolves when it encounters water in the wellbore, and the compressed check assembly 18 radially extends, thereby preventing the plugging head 15 from returning to the initial position and blocking the coiled tubing;

[0060] S5. When the gas well adopts downhole throttling production and liquid begins to accumulate in the wellbore, a steel ball 25 is thrown into the coiled tubing to the upper sleeve 7, and nitrogen is injected into the coiled tubing and gradually pressurized to push the steel ball 25 and the upper sleeve 7 to move together, thereby shearing off the first shear pin 5 until the upper sleeve 7 moves to the connecting pipe 9, and the first outlet 6 is opened, and the coiled tubing is used as a velocity string to discharge the liquid accumulated in the wellbore;

[0061] S6. When liquid accumulation appears in the gas wellbore again, a plunger 26 is thrown into the coiled tubing to the upper joint 1, and the gas production device is used as a receiver of the plunger 26. The plunger 26 is used to drain water and produce gas until the gas well reaches the abandonment pressure.

[0062] Taking the example of Φ50.8mm coiled tubing under pressure after Φ114.3mm casing fracturing construction to complete the well, the specific operation process is as follows:

[0063] 1. Run the coiled tubing under pressure

[0064] On the ground, the integrated completion device is installed according to Figure 3 After the assembly is completed, insert the Φ50.8mm coiled tubing into the upper joint 1, the conical slip 2, the cone sleeve 3 and the inner cavity of the lower joint 4. The upper joint 1 and the lower joint 4 are gradually pushed forward and tightened through the thread. The upper joint 1 pushes the conical slip 2 and the cone sleeve 3 to produce relative movement, forcing the conical slip 2 to retract and gradually hold the coiled tubing until it is locked. Figure 3 The device shown is lowered into the Φ114.3mm casing together with the coiled tubing to the designed depth, and the coiled tubing hanging, pipe cutting, sealing and gas wellhead installation are completed in sequence.

[0065] 2. Remove the plug 15 and return the fracturing fluid

[0066] Connect a nitrogen truck or other pressurizing device to the wellhead gas tree venting test valve, inject nitrogen into the coiled tubing and gradually pressurize it until the pressure reaches 3MPa, at which time the third shear nail 16 is cut off. Figure 4 As shown, the plugging head 15 falls into the pocket of the sand cover 23. As the plugging head 15 falls, the second outlet 13 is opened. The flow area of ​​the second outlet 13 is the same as the flow area of ​​the Φ50.8mm continuous oil pipe, ensuring that the fracturing fluid that has not been discharged using the Φ114.3mm casing can be discharged smoothly along the second outlet 13.

[0067] 3. Throw in a soluble ball 24 to close the second outlet 13

[0068] like Figure 5 As shown, at the gas production wellhead, a soluble ball 24 of Φ26 mm is thrown into the coiled tubing to the lower sleeve 11 through the gas tree venting test valve, a nitrogen truck or other pressurizing device is connected to the wellhead gas tree venting test valve, nitrogen is injected into the coiled tubing and gradually pressurized, the outer diameter of the soluble ball 24 is larger than the inner diameter of the lower sleeve 11, and the high-pressure nitrogen pushes the soluble ball 24 and the lower sleeve 11 to move together, thereby shearing the second shear nail 12 until the lower sleeve 11 moves to the second connecting pipe 17, the outer diameter of the lower sleeve 11 is larger than the inner diameter of the second connecting pipe 17, at this time, along with the movement of the lower sleeve 11, the second outlet 13 is closed, the lower sleeve 11 moves down to the expanded diameter of the second outer tube 10, the check spring 14 originally in a compressed state is extended, thereby preventing the lower sleeve 11 from moving back to its original position, the soluble ball 24 is completely dissolved after contacting the fracturing fluid or water, and the downhole choke production begins.

[0069] 4. Underground throttling production

[0070] When the gas well is opened for production, the high-pressure natural gas and other fluids in the formation flow through the sand cover 23, the pressure cap 22, and the gas nozzle 21 in sequence, enter the coiled tubing and reach the surface gathering and transportation pipeline network. Since the diameter of the gas nozzle 21 is 2-8mm, the high-pressure natural gas will produce a throttling and pressure reduction effect when passing through the gas nozzle 21, thereby realizing the downhole throttling production of the gas well. Figure 6 As shown, when the natural gas in the wellbore flows at a high speed, it may impact the plugging head 15 to move upward, or even return to the initial position and block the coiled tubing. Since the soluble material at one end of the non-return component 18 dissolves when encountering water in the wellbore, the non-return component 18, which was originally in a compressed state, recovers its deformation and radially extends, thereby preventing the plugging head 15 from returning to the initial position and blocking the coiled tubing.

[0071] 5. Throw steel ball 25 to open the upper sliding sleeve 7 speed string for drainage and gas production

[0072] After a period of downhole throttling production, as the production capacity declines, liquid begins to accumulate in the wellbore. Since the diameter of the gas nozzle 21 is 2-8 mm, the flow area is small and the friction resistance is large when the liquid flows through, which seriously affects drainage and gas production.

[0073] like Figure 7 As shown, at the gas production wellhead, a Φ30mm steel ball 25 is thrown into the coiled tubing to the upper sleeve 7 through the gas tree venting test valve, and a pressurizing device such as a nitrogen truck is connected to the wellhead gas tree venting test valve, and nitrogen is injected into the coiled tubing and gradually pressurized. Since the outer diameter of the steel ball 25 is larger than the inner diameter of the upper sleeve 7, the high-pressure nitrogen pushes the steel ball 25 and the upper sleeve 7 to move together, thereby shearing the first shear nail 5 until the upper sleeve 7 moves to the first connecting pipe 9. At this time, along with the movement of the upper sleeve 7, the first outlet 6 is opened, and the flow area of ​​the first outlet 6 is not less than the flow area of ​​the coiled tubing, ensuring that the wellbore liquid can be effectively discharged when the Φ50.8mm coiled tubing is used as the velocity string for production.

[0074] 6. Release plunger 26 to drain water and produce gas

[0075] As the gas well productivity declines, when the production is lower than the critical liquid carrying flow rate of the Φ50.8mm coiled tubing, liquid accumulation occurs again in the gas wellbore. Figure 8 As shown, at the wellhead, a Φ38mm plunger 26 is thrown into the coiled tubing through the gas tree venting test valve. The device of the present invention can be used as a receiver for the plunger 26. The inner diameter of the upper joint 1 is adapted to the size of the plunger 26. The plunger 26 is used to drain water and produce gas until the gas well reaches the abandonment pressure. At this point, the full life cycle production of the gas well from production to abandonment is completed.

[0076] In summary, the process method of the present invention realizes pressure-carrying pipe, fracturing fluid return, downhole throttling production, velocity string water drainage and gas production, and plunger gas lift water drainage and gas production in sequence, covering the entire life cycle of the gas well from the initial completion to the abandonment, ensuring the orderly connection of various water drainage and gas production measures, saving the cost of launching and salvaging operations of preset throttles and cava throttles, avoiding downhole accidents caused by the failure of launching and salvaging these two types of throttles, and meeting the full life cycle production needs of the gas well from commissioning to scrapping.

[0077] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A gas well completion and gas production device for the entire life cycle of a gas well. It is characterized in that The invention comprises an upper joint (1), a lower joint (4), a first outer tube (8), a first connecting pipe (9), a second outer tube (10), a second connecting pipe (17), a third outer tube (19) and a valve seat (20) which are connected in sequence by threads, wherein the threaded connections are all provided with sealing structures. The inner wall of the first outer cylinder (8) is provided with a first connecting structure, and the first connecting structure is used to connect or separate the inner and outer spaces of the first outer cylinder (8) according to the life cycle of the gas well; The inner wall of the second outer cylinder (10) is provided with a second connecting structure, and the second connecting structure is used to connect or separate the inner and outer spaces of the second outer cylinder (10) according to the life cycle of the gas well.

2. A gas well full life cycle completion and gas production device according to claim 1, It is characterized in that An air nozzle (21) is inserted into the air nozzle seat (20), one end of the air nozzle (21) is inserted into the air nozzle seat (20), and the other end is provided with a pressure cap (22), the pressure cap (22) is connected to the air nozzle seat (20) by means of a thread, a sand-proof cover (23) is provided on the outer side of the pressure cap (22), the sand-proof cover (23) is connected to the air nozzle seat (20) by means of a thread, and a sealing structure is provided at the threaded connection.

3. A gas well full life cycle completion and gas production device according to claim 1, It is characterized in that The inner cavity of the upper joint (1) is provided with a conical slip (2) and a conical sleeve (3).

4. A gas well full life cycle completion and gas production device according to claim 1, It is characterized in that The first connecting structure comprises a first shear pin (5), an upper sleeve (7) and a first outlet (6); the inner wall of the first outer cylinder (8) is fixedly connected to the upper sleeve (7) via the first shear pin (5); the cylinder wall of the first outer cylinder (8) is provided with a first outlet (6); the upper sleeve (7) covers the first outlet (6); and the flow area of ​​the first outlet (6) is not less than the flow area of ​​the coiled tubing.

5. A gas well full life cycle completion and gas production device according to claim 4, It is characterized in that The second connecting structure comprises a second shearing nail (12), a lower sleeve (11), a second outlet (13) and a plugging head (15); the inner wall of the second outer cylinder (10) is fixedly connected to the outer wall of the lower sleeve (11) by the second shearing nail (12); the cylinder wall of the second outer cylinder (10) is provided with a second outlet (13); the lower sleeve (11) is provided with a through hole at a position corresponding to the second outlet (13); the lower sleeve (11) is provided with a plugging head (15); one end of the plugging head (15) covers the through hole; the other end of the plugging head (15) is provided with a limiting block and is connected to the second connecting pipe (17) by a third shearing nail (16); and one end of the second connecting pipe (17) is provided with a limiting groove corresponding to the limiting block.

6. A gas well full life cycle completion and gas production device according to claim 5, It is characterized in that The second outer tube (10) is a reducing tube, and the inner diameter of the end of the second outer tube (10) close to the first connecting tube (9) is smaller than the inner diameter of the end close to the second connecting tube (17); The lower sleeve (11) is located at one end of the second outer tube (10) close to the first connecting tube (9), and a check spring (14) is provided at one end of the lower sleeve (11) close to the second connecting tube (17). The check spring (14) is located between the second outer tube (10) and the lower sleeve (11). One end of the check spring (14) is in contact with the inner wall of the second outer tube (10), and the other end of the check spring (14) is fixedly connected to the lower sleeve (11) by a pin. The check spring (14) is in a compressed state.

7. A gas well full life cycle completion and gas production device according to claim 6, It is characterized in that A check assembly (18) is provided at one end of the second connecting tube (17) close to the third outer tube (19), and the check assembly (18) is in a compressed state. One end of the check assembly (18) is fixedly connected to the inner wall of the second connecting tube (17) by a pin, and the other end of the check assembly (18) is fixed by a soluble material.

8. A gas well full life cycle completion and gas production device according to claim 7, It is characterized in that It also includes a soluble ball (24), a steel ball (25) and a plunger (26), The outer diameter of the soluble ball (24) is larger than the inner diameter of the lower sleeve (11) and smaller than the inner diameters of the first connecting pipe (9) and the second outer cylinder (10). The soluble ball (24) gradually dissolves when it encounters fracturing fluid or water and can be completely dissolved within 30 days. The outer diameter of the steel ball (25) is larger than the inner diameter of the upper sliding sleeve (7) and smaller than the inner diameter of the first outer cylinder (8); The size of the plunger (26) is adapted to the inner diameter of the upper connector (1); The soluble ball (24), the steel ball (25) and the plunger (26) are used to be sequentially put into the gas production device from the upper joint (1) according to the life cycle of the gas well.

9. A gas well full life cycle completion and gas production device according to claim 5, It is characterized in that The strengths of the third shear nail (16), the second shear nail (12) and the first shear nail (5) are enhanced in sequence.

10. A gas well completion and gas production process for the entire life cycle of a gas well. It is characterized in that The method uses the device according to any one of claims 1 to 9 to complete the well and produce gas, comprising: S1. Insert the coiled tubing into the inner cavity of the upper joint (1), the conical slip (2), the cone sleeve (3) and the lower joint (4) until it is locked, lower the coiled tubing and the gas production device into the casing to a preset depth, and complete the coiled tubing hanging, pipe cutting, sealing and gas wellhead installation in sequence; S2. Nitrogen is injected into the coiled tubing and gradually pressurized, so that the third shear nail (16) is sheared off, the plug (15) falls into the sand cover (23), the second outlet (13) is opened, and the fracturing fluid is returned; S3. A soluble ball (24) is thrown into the coiled tubing to the lower sleeve (11), and nitrogen is injected into the coiled tubing and gradually pressurized to push the soluble ball (24) and the lower sleeve (11) to move together, thereby shearing off the second shear nail (12) until the lower sleeve (11) moves to the connecting pipe (17), closing the second outlet (13), and the lower sleeve (11) moves down to the expanded diameter of the second outer tube (10). The compressed check spring (14) is extended to prevent the lower sleeve (11) from moving up to its original position. The soluble ball (24) is completely dissolved after contacting the fracturing fluid or water, and production using the downhole choke is started; S4. When the gas well is opened for production, the soluble material at one end of the check assembly (18) dissolves when it encounters water in the wellbore, and the compressed check assembly (18) radially extends, thereby preventing the plugging head (15) from returning to the initial position and blocking the coiled tubing; S5. When the gas well adopts downhole throttling production and liquid begins to accumulate in the wellbore, a steel ball (25) is thrown into the coiled tubing to the upper sleeve (7), and nitrogen is injected into the coiled tubing and gradually pressurized to push the steel ball (25) and the upper sleeve (7) to move together, thereby shearing off the first shear pin (5) until the upper sleeve (7) moves to the connecting pipe (9), and the first outlet (6) is opened, and the coiled tubing is used as a velocity string to discharge the liquid accumulated in the wellbore; S6. When liquid accumulation occurs again in the gas wellbore, a plunger (26) is inserted into the coiled tubing to the upper joint (1), and the gas production device is used as a receiver of the plunger (26). The plunger (26) is used to drain water and produce gas until the gas well reaches the abandonment pressure.

Images