Gas-liquid huff-puff oil production pipe column and huff-puff oil

Abstract

The invention discloses a gas-liquid huff and puff oil production string and a huff and puff oil production method.The gas-liquid huff and puff oil production string sequentially comprises a guide plug, a screen pipe, a packer, a safety connector, a bypass valve, a conversion gas anchor, a rod pump and an oil pipe from bottom to top, an outer barrel is connected to the periphery of the lower end of a gas anchor upper connector in the conversion gas anchor, and a center pipe is connected to the inner periphery of the lower end of the gas anchor upper connector; a gas anchor lower joint is screwed into the lower port of the outer cylinder, a sliding sleeve is inserted into the lower port of the central pipe and is fixed through a shear pin, the lower end of the sliding sleeve is inserted into a central hole of the gas anchor lower joint and is connected with a locking ring, and inner ratchets are arranged on the inner wall of the locking ring; a spiral inner pipe is arranged between the central pipe and the outer cylinder, the lower end of the spiral inner pipe is connected with external threads at the lower end of the central pipe, spiral pieces are wound on the periphery of the spiral inner pipe, and a plurality of inner pipe air holes are formed between the lower spiral pieces and communicated with an inner cavity of the spiral inner pipe; and the periphery of the sealing baffle ring is sealed with the inner wall of the upper part of the outer cylinder. Gas and liquid huff and puff and oil extraction production can be completed by one tubular column.

Description

Technical Field

[0001] The present invention relates to an oil production string, in particular to a gas-liquid throughput oil production string. The present invention also relates to a throughput oil production method of the gas-liquid throughput oil production string, and relates to the technical field of throughput oil production. Background Art

[0002] For low permeability oil reservoirs and heavy oil reservoirs, gas-liquid huff-and-puff development has unique advantages. By injecting gas and liquid into the oil well, the viscosity of crude oil is greatly reduced and the formation energy is replenished. After the well is shut down, the oil is extracted from the same well to increase crude oil production.

[0003] For gas-liquid throughput tubing, an air anchor is usually installed under the oil pump. Its function is to separate some of the gas before the downhole fluid enters the pump, reducing the impact of the gas on the pump and improving pump efficiency. The main body of the traditional air anchor is a cylindrical structure with an annular space inside for receiving the oil-gas mixture. The lower channel of the central tube is connected to the annular space, and the top is connected to the inner tube pump. Its disadvantage is that it can only separate oil and gas, and cannot serve as a closed channel for gas or liquid injection, and cannot achieve closed injection of gas or liquid from top to bottom. Therefore, the current oil well gas and liquid throughput process requires two trips of tubing, that is, first lowering the throughput tubing with a packer to inject gas or liquid, and then switching to the pump for production after the throughput and blowdown are completed. This not only increases the operating cost, but also poses risks of reservoir contamination and well control during the operation and well washing process.

[0004] A packer needs to be installed above the formation. Conventional packers have a short effective seal and are prone to failure. Their small internal diameter also makes them susceptible to jamming. Self-expanding packers significantly alleviate these issues. They can be used in both cased and open-hole wells, addressing water intrusion and corrosion. They can replace conventional packers for interlayer annular space isolation and maintain a good seal even in harsh conditions such as rough terrain. However, self-expanding packers still have the following problems: they require a long and thick rubber to meet pressure resistance requirements and ensure a seal; conventional self-expanding packers lack a release mechanism and backwash channel, and self-expanding can also lead to uneven expansion. Summary of the Invention

[0005] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the abstract and title of the invention of this application, and such simplifications or omissions cannot be used to limit the scope of the present invention.

[0006] In view of the above problems and / or the problems existing in the prior art, the present invention is proposed.

[0007] The primary purpose of the present invention is to overcome the problems existing in the prior art and provide a gas-liquid throughput oil production tubing string that can complete gas and liquid throughput and oil production in one trip.

[0008] In order to solve the above technical problems, a gas-liquid throughput production string of the present invention includes a guide wire plug A, a screen tube B, a packer C, a safety joint D, a bypass valve E, a conversion gas anchor F, a rod pump G and an oil pipe H connected in sequence from bottom to top. In the conversion gas anchor F, the lower end of the gas anchor upper joint 31 is externally threadedly connected to the outer cylinder 32, the lower end of the gas anchor upper joint 31 is internally threadedly connected to the center pipe 36, the lower end of the outer cylinder 32 is threadedly connected to the gas anchor lower joint 42, the lower end of the center pipe 36 is inserted into the sliding sleeve 39 and fixed by a shear nail 38, the lower end of the sliding sleeve 39 is inserted into the center hole of the gas anchor lower joint 42 and connected to a locking ring 41, the inner wall of the locking ring 41 is provided with an internal ratchet; A spiral inner tube 35 is provided between the central tube 36 and the outer tube 32. The lower end of the spiral inner tube 35 is connected to the external thread of the lower end of the central tube 36. A spiral sheet 34 is wrapped around the outer periphery of the spiral inner tube 35. A plurality of inner tube air holes 5a are provided between the lower spiral sheets 34 and communicate with the inner cavity annulus of the spiral inner tube 35. A sealing retaining ring 33 is screwed to the upper outer periphery of the spiral inner tube 35, and the outer periphery of the sealing retaining ring 33 is sealed with the upper inner wall of the outer tube 32.

[0009] Furthermore, the upper part of the sleeve 39 is the upper sealing section of the sleeve, and the outer periphery of the upper sealing section of the sleeve is embedded with an O-ring 37 to seal with the lower inner wall of the center tube 36. The lower part of the sleeve 39 is provided with a lower sealing section of the sleeve, and the outer periphery of the lower sealing section of the sleeve is embedded with a sealing ring to achieve sealing with the upper inner wall of the air anchor lower joint 42; a plurality of retaining spring grooves are provided on the circumference below the lower sealing section of the sleeve 39, and a retaining spring 40 is embedded in each retaining spring groove.

[0010] Furthermore, the upper outer step of the sliding sleeve 39 abuts against the first inner step at the lower end of the center tube 36, and the upper outer step of the expanded diameter section of the sliding sleeve 39 abuts against the second inner step at the lower end of the center tube 36; the upper end of the sliding sleeve 39 is provided with a chamfer that is wider at the top and narrower at the bottom, and the inner diameter of the sliding sleeve 39 is smaller than the inner diameter of the center tube 36.

[0011] Furthermore, the outer cylinder 32 is provided with an outer cylinder liquid inlet 32a and an outer cylinder exhaust hole 32b. The outer cylinder liquid inlet 32a is located below the sealing ring 33, and the outer cylinder exhaust hole 32b is located between the top of the sealing ring 33 and the bottom of the air anchor upper joint 31.

[0012] Furthermore, the inner diameter of the sleeve 39 matches the outer diameter of the plug 43, and the lower end of the plug 43 is provided with an outer ratchet 43a; after the plug 43 is put into the pipe column and falls into the sleeve 39, the outer ratchet 43a at the lower end of the plug 43 is locked by the inner ratchet of the locking ring 41; when the shear nail 38 is cut off, the sleeve 39 descends until the bottom of the outer step abuts against the upper end of the air anchor lower joint 42, and the retaining spring 40 reaches below the lower port of the air anchor lower joint 42 and stretches open, preventing the sleeve 39 from ascending.

[0013] Furthermore, the packer C includes a core tube 20, the upper and lower ends of which are respectively connected to the packer upper joint 1 and the packer lower joint 19, the middle section of the core tube 20 is sheathed with a support tube 13, and a gap is provided between the inner wall of the support tube 13 and the outer wall of the core tube 20 as an annular backwash channel; the outer periphery of the support tube 13 is sheathed with a self-expanding rubber tube 14, and the upper and lower ends of the self-expanding rubber tube 14 are respectively embedded in the limiting end ring 12; the upper and lower ports of the support tube 13 are respectively provided with inner conical surfaces, the inner conical surface of the upper port of the support tube 13 abuts against the lower outer conical surface of the lower end of the movable expansion ring 11, and the middle and lower inner wall of the movable expansion ring 11 abuts against the outer wall of the core tube 20 and is sealed with the core tube 20; the inner conical surface of the lower port of the support tube 13 abuts against the upper outer conical surface of the upper end of the fixed expansion ring 15, and the inner wall of the fixed expansion ring 15 is screwed to the external threaded section of the middle and lower part of the core tube 20.

[0014] Furthermore, the fixed expansion ring 15 is provided with a plurality of lower backwash channels 15a extending axially, and the upper port of each lower backwash channel 15a is connected to the lower port of the annular backwash channel; the circumference of the movable expansion ring 11 is provided with a plurality of upper backwash channels 11c extending axially, and the lower end of each upper backwash channel 11c is connected to the upper port of the annular backwash channel.

[0015] Furthermore, the movable expansion ring 11 is located in the annular space between the hydraulic chamber sleeve 10 and the core tube 20, and the middle section of the hydraulic chamber sleeve 10 is provided with an inner step with a reduced diameter to achieve sealing with the middle outer wall of the movable expansion ring 11; the upper end of the movable expansion ring 11 is provided with an outwardly bent outer convex ring 11a, and the outer wall of the outer convex ring 11a is gap-fitted with the inner wall of the hydraulic chamber sleeve 10, and the return spring 21 is supported between the outer convex ring 11a of the movable expansion ring 11 and the inner step of the hydraulic chamber sleeve 10.

[0016] Furthermore, the upper limiting end ring 12 is sleeved on the lower outer periphery of the hydraulic chamber sleeve 10 and the top is against the bottom of the outer step of the hydraulic chamber sleeve 10, and the lower limiting end ring 12 is sleeved on the outer periphery of the backwash connecting sleeve 16, and the upper inner wall of the backwash connecting sleeve 16 is threadedly connected to the outer wall of the fixed expansion ring 15.

[0017] Furthermore, the upper end of the hydraulic chamber sleeve 10 is connected to the outer wall of the lower end of the hydraulic valve, the lower inner wall of the hydraulic valve is screwed to the outer wall of the core tube 20, and the upper part of the hydraulic valve is embedded between the core tube 20 and the lower inner wall of the hydraulic valve sleeve 2; the upper external thread of the hydraulic valve sleeve 2 is connected to the internal thread of the lower end of the upper joint 1 of the packer, the top of the hydraulic valve sleeve 2 rests under the inner step of the upper joint 1 of the packer, the lower port of the upper joint 1 of the packer rests on the outer step of the hydraulic valve sleeve 2, and the upper internal thread of the hydraulic valve sleeve 2 is connected to the upper external thread of the core tube 20.

[0018] Furthermore, the hydraulic valve includes an annular valve body 3, which is sleeved on the upper periphery of the core tube 20, and the lower inner wall of the valve body 3 is screwed to the core tube 20; an axially penetrating valve body axial channel is provided along the middle of the valve body wall thickness, and the valve body axial channel is thin in the middle and thick at both ends; a bell mouth opening downward is provided at the lower diameter change part of the valve body axial channel, and a valve ball 6 is sealed at the bell mouth, and the bottom of the valve ball 6 is supported in the concave arc at the top of the valve support 7, and a valve support center rod is provided at the center of the lower end face of the valve support 7. A valve body spring 8 is sleeved on the outer periphery of the valve support center rod, and the upper end of the valve body spring 8 rests on the bottom of the valve support 7, and the lower end of the valve body spring 8 is supported in the center countersunk hole of the upper end face of the pressure cap 9, and the external thread of the pressure cap 9 is screwed into the internal thread at the lower end of the valve body axial channel, and the center of the pressure cap 9 is provided with a through pressure cap center hole communicating with the space below.

[0019] Furthermore, a valve plug 5 is provided in the upper inner cavity of the axial channel of the valve body, and a valve plug tail rod 5b extending downward is provided at the bottom center of the valve plug 5, and the lower end of the valve plug tail rod 5b is close to the valve ball 6; the upper part of the valve plug 5 is sealed with the upper inner wall of the axial channel of the valve body, and the top of the valve plug 5 is provided with a valve plug reduction section 5a, and the outer periphery of the valve plug reduction section 5a forms an annular flow space, and the upper outer wall of the valve body 3 is provided with a valve body unsealing water inlet 3a which is communicated with the annular flow space; a plug 4 is pressed above the valve plug reduction section 5a, and the plug 4 is screwed into the upper port of the axial channel of the valve body; a valve sleeve unsealing water inlet 2a is provided on the lower outer wall of the hydraulic valve sleeve 2 which is communicated with the outer port of the valve body unsealing water inlet 3a.

[0020] Furthermore, axially penetrating tail rod grooves 5c are symmetrically provided on both sides of the valve plug tail rod 5b as axial flow channels for water flow; the middle inner wall of the valve body 3 is provided with a valve body seat seal water inlet 3b which is connected to the axial flow channel on the outer periphery of the valve plug tail rod 5b; the core tube 20 is provided with a core tube water inlet hole 20a which is connected to the outer port of the valve body seat seal water inlet 3b.

[0021] Furthermore, a backwash ring cavity is provided below the inner step sealing section in the middle of the hydraulic cavity sleeve 10, and a backwash water inlet 10a is provided on the outer wall of the hydraulic cavity sleeve 10 to communicate with the backwash ring cavity; the upper ends of each upper backwash channel 11c of the movable expansion ring 11 are respectively communicated with the backwash ring cavity through the movable expansion ring radial hole 11b.

[0022] Furthermore, the lower end internal thread of the backwash connecting sleeve 16 is connected to the upper end external thread of the lower joint 19 of the packer, and the upper end internal thread of the lower joint 19 of the packer is connected to the lower end external thread of the core tube 20; a radially through-going backwash outlet 16a is provided in the middle and upper part of the backwash connecting sleeve 16, and a backwash retaining ring 17 and a backwash spring 18 are provided in the annular space between the backwash connecting sleeve 16 and the core tube 20, the lower end of the backwash spring 18 is supported on the top of the lower joint 19 of the packer, and the upper end of the backwash spring 18 is supported below the backwash retaining ring 17, the inner wall of the backwash retaining ring 17 is abutted against the outer wall of the core tube 20, and the outer wall of the backwash retaining ring 17 is abutted against the inner wall of the backwash connecting sleeve 16 and blocks the inner port of the backwash outlet 16a.

[0023] Furthermore, the safety joint D includes: The hand-discharging upper joint 22 has a middle section outer wall symmetrically provided with downwardly opening grooves; The lower release joint 27 has an upper portion which is sleeved on the outer periphery of the lower portion of the release joint 22 and is fixedly connected to the release joint 22 via release shear nails 23. The upper end is symmetrically provided with tenons, each tenon being embedded in a groove of the release joint 22. The sealing bushing 26 has an upper external thread section connected to the internal thread of the lower end of the release joint 22. The lower outer wall of the upper external thread section is sealed with the lower inner wall of the release joint 22. The lower end of the sealing bushing 26 is expanded to form an outer step and is sealed with the lower inner wall of the release lower joint 27. The soluble release ring 25 is located in the annular space between the middle inner wall of the lower release joint 27 and the outer wall of the sealing bushing 26. The inner circumferential wall of its upper end abuts against the middle outer circumferential wall of the sealing bushing 26. There is a gap between the inner wall below the upper inner step and the middle outer wall of the sealing bushing 26 and it is flush with the lower inner wall of the lower release joint 27. The external thread on the lower outer periphery of the soluble release ring 25 is connected to the internal thread above the inner step of the lower release joint 27.

[0024] Furthermore, the top of the soluble release ring 25 rests against the bottom of the release upper joint 22, and the bottom of the soluble release ring 25 rests against the inner step of the release lower joint 27; the top of the sealing bushing 26 rests against the bottom of the inner step of the release upper joint 22, and the sealing bushing 26 is flush with the inner wall of the release upper joint 22.

[0025] Furthermore, the bypass valve E includes a bypass upper joint 28, the lower end of the bypass upper joint 28 is screwed with a bypass lower joint 30, the middle section of the bypass lower joint 30 is provided with a plurality of through bypass flow grooves 30a, the inner cavity of the bypass lower joint 30 is provided with an inner sleeve 29 and is fixed to the bypass lower joint by a pin 29b, the upper end of the inner sleeve 29 is provided with a bell mouth for ball setting, and the upper and lower outer peripheries of the inner sleeve 29 are respectively embedded with inner sleeve sealing rings 29a to achieve sealing with the upper and lower inner walls of the bypass lower joint 30.

[0026] Another object of the present invention is to overcome the problems existing in the prior art and provide a throughput oil production method for a gas-liquid throughput oil production string, which can complete gas and liquid throughput and oil production in one trip of the string.

[0027] To solve the above technical problems, the present invention provides a gas-liquid throughput oil production method for a production string, which comprises the following steps in sequence: S1, throw the ball to set the packer C; S2, injecting gas or liquid into the oil layer through the rod pump G, conversion gas anchor F, bypass valve E, safety joint D and the central channel of the packer C; S3, soaking the well to reduce the viscosity of crude oil; S4, opening the wellhead to start flowing oil production; S5, throw the ball to open the bypass valve E; S6, throwing a plugging device to close the bottom channel of the conversion air anchor F; S7. Connect the plunger to the lower part of the sucker rod and lower the sucker rod and the connected plunger into the well using the sucker rod elevator until the plunger enters the pump barrel of the rod pump G. S8. Start the pumping unit on the ground. Under the pumping action of the rod pump G, the oil from the formation enters the annulus above the packer C through the bypass valve E, and then enters the conversion air anchor F from the upper part of the conversion air anchor F for gas-liquid separation. The degassed oil is sent to the wellhead through the rod pump G and the oil pipe H.

[0028] Furthermore, the setting of the packer C in step S1 includes the following sub-steps: S1.1. Apply pressure through the oil pipe, causing water to flow out from the core tube water inlet 20a on the core tube 20 and enter the middle section of the valve body axial channel through the valve body seat seal water inlet 3b; S1.2. Push down the valve ball 6 in the hydraulic valve, allowing water to enter the space above the movable expansion ring 11, pushing the movable expansion ring 11 downward and compressing the return spring 21. S1.3. The outer conical surface at the lower end of the movable expansion ring 11 and the outer conical surface at the upper end of the fixed expansion ring 15 jointly squeeze the support tube 13 to expand evenly outward, achieving mechanical sealing expansion of the self-expanding rubber tube 14. S1.4. After the pressurization is stopped, the hydraulic valve is closed, and the pressure is maintained above the movable expansion ring 11. The self-expanding rubber cylinder 14 absorbs water and continues to expand on the basis of mechanical expansion until it is close to the pipe wall, completing the coupled expansion of mechanical expansion and self-expansion.

[0029] Furthermore, when the packer needs to be backwashed in the set state, the following steps are performed: A1. Pressurize the oil casing annulus so that water enters the backwash annulus from the backwash water inlet 10a on the hydraulic chamber sleeve 10; A2. Backwash water sequentially passes through the upper backwash channel 11c of the movable expansion ring 11, the gap between the support tube 13 and the core tube 20, and the lower backwash channel 15a of the fixed expansion ring 15; A3. The backwash water pushes the backwash retaining ring 17 to compress the backwash spring 18 and move it downward, opening the backwash outlet 16a on the backwash connecting sleeve 16, and the backwash water flows out from the backwash outlet 16a; A4. The backwash water continues to flow downward into the lower port of the tubing string and returns to the wellhead along the central channel to achieve backwashing.

[0030] Furthermore, when the packer needs to be unsealed, the following steps are performed: B1. Pressurize the annulus of the oil casing to allow water to enter through the valve sleeve unsealing water inlet hole 2a on the hydraulic valve sleeve 2; B2. Push the valve plug 5 downward, and the valve plug tail stem 5b at the lower end of the valve plug 5 pushes the valve ball 6 away; B3, water flows out from the core tube water inlet 20a on the core tube 20 to complete the internal pressure relief of the hydraulic valve; B4. The return spring 21 extends, the movable expansion ring 11 returns upward, the support tube 13 and the movable expansion ring 11 lose support, and the seal is released.

[0031] Furthermore, when the packer fails to be unsealed, the following steps are performed: the tubing is lifted with a certain load to cut the release shear pin 23, thereby moving the release joint 22 and the sealing bushing 26 upward together. After the lower outer step of the sealing bushing 26 contacts the upper inner step of the soluble release ring 25, the lower sealing section of the sealing bushing 26 reaches the upper middle part of the soluble release ring 25, so that the lower inner wall of the soluble release ring 25 contacts the well fluid. The soluble release ring 25 will gradually dissolve when immersed in the high-mineralization well fluid, thereby lifting the upper tubing string and then salvaging the lower tubing string.

[0032] Compared with the existing technology, the present invention has achieved the following beneficial effects: 1. The throughput production achieves a win-win situation for environmental protection and efficient development of crude oil. The core tube of the conversion gas anchor serves as an injection channel for gas or liquid during gas or liquid throughput, realizing closed injection; during oil production, it can be used as a gas anchor after being pressurized by a plugger, achieving the purpose of integrated gas and liquid throughput and oil production; greatly reducing the well occupation period and saving operating costs; and it can reduce reservoir pollution and reduce well control risks.

[0033] 2. The packer features a hydraulic valve, expansion ring, and support tube, which work together to achieve a coupled expansion effect of mechanical and self-expansion. The hydraulic valve solves the problem of conventional self-expanding packers, which suffer from excessive resistance in the rubber tube when the tubing string needs to be moved, allowing for smooth packing. A backwash channel is established, and backwashing is achieved through the use of a backwash retaining ring and backwash spring, making the self-expanding packer simple and convenient, meeting all backwashing requirements.

[0034] 3. Set up a bypass valve to introduce the formation oil into the annulus above the packer, so as to facilitate the entry of the conversion gas anchor for degassing, protect the rod pump and improve the pump efficiency.

[0035] 4. When the packer fails to release, the release shear pins are cut by lifting the tubing, so that the release joint and the sealing bushing move upward together. The soluble release ring contacts the well fluid and gradually dissolves under the immersion of high-salinity well fluid, achieving reliable release. This ensures that the upper tubing can be lifted out and the lower tubing can be salvaged, reducing the risk of overhaul, saving operating costs, and shortening the well occupation period. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive work. The drawings are provided for reference and explanation only and are not intended to limit the present invention. Among them: Figure 1 This is a schematic structural diagram of the gas-liquid throughput production string of the present invention; Figure 2 Schematic diagram of the structure of the packer in the present invention; Figure 3 It is a structural diagram of the hydraulic valve in the packer; Figure 4 Schematic diagram of the structure of the safety joint in the present invention; Figure 5 Schematic diagram of the structure of the bypass valve in the present invention; Figure 6 This is a state diagram of the conversion of the air anchor in the present invention; In the figure: A. Guide wire plug; B. Screen tube; C. Packer; D. Safety joint; E. Bypass valve; F. Conversion air anchor; G. Rod pump; H. Tubing; C. Packer: 1. Packer connector; 2. Hydraulic valve sleeve; 2a. Valve sleeve unsealing water inlet; 3. Valve body; 3a. Valve body unsealing water inlet; 3b. Valve body seat seal water inlet; 4. Plug; 5. Valve plug; 5a. Valve plug reduction section; 5b. Valve plug tail stem; 5c. Tail stem groove; 6. Valve ball; 7. Valve support; 8. Valve body spring; 9. Pressure cap; 10. Hydraulic chamber sleeve; 10a. Backwash water inlet; 11. Expansion ring ; 11a. Outer convex ring; 11b. Radial hole of movable expansion ring; 11c. Upper backwash channel; 12. Restriction end ring; 13. Support tube; 14. Self-expanding rubber cylinder; 15. Fixed expansion ring; 15a. Lower backwash channel; 16. Backwash connecting sleeve; 16a. Backwash water outlet; 17. Backwash retaining ring; 18. Backwash spring; 19. Lower joint of packer; 20. Core tube; 20a. Core tube water inlet hole; 21. Return spring.

[0037] D. Safety connector: 22. Hand release connector; 23. Hand release shear pin; 24. O-ring; 25. Fusible hand release ring; 26. Sealing bushing; 26a. Bushing upper sealing ring; 26b. Bushing lower sealing ring; 27. Hand release lower connector; 27a. Tenon; E. Bypass valve: 28. Bypass upper connector; 29. ​​Inner sleeve; 29a. Inner sleeve seal; 29b. Pin; 30. Bypass lower connector; 30a. Bypass flow channel; F. Conversion air anchor: 31. Air anchor upper connector; 32. Outer tube; 32a. Liquid inlet of outer tube; 32b. Exhaust hole of outer tube; 33. Sealing ring; 34. Spiral plate; 35. Spiral inner tube; 35a. Air hole of inner tube; 36. Center tube; 37. O-ring; 38. Shear pin; 39. Sleeve; 40. Circlip; 41. Locking ring; 42. Air anchor lower connector; 43. Plug; 43a. External ratchet. DETAILED DESCRIPTION

[0038] In the following description of the present invention, the terms "up", "down", "front", "back", "left", "right", "inside", "outside", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not mean that the device must have a specific direction.

[0039] In order to make the technical means, creative features, objectives and effects of the present invention easier to understand, the present invention is further described below with reference to specific figures. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present invention pertains. The terms used herein in the specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention.

[0041] like Figure 1 As shown, the gas-liquid huff-and-puff production string of the present invention includes a guide wire plug A, a screen tube B, a packer C, a safety joint D, a bypass valve E, a conversion gas anchor F, a rod pump G and an oil pipe H connected in sequence from bottom to top.

[0042] like Figure 2 、 Figure 3 As shown, the packer in the present invention includes a packer upper joint 1, a hydraulic valve sleeve 2, a valve body 3, a plug 4, a valve plug 5, a valve ball 6, a valve support 7, a valve body spring 8, a pressure cap 9, a hydraulic chamber sleeve 10, a movable expansion ring 11, a limiting end ring 12, a support tube 13, a self-expanding rubber tube 14, a fixed expansion ring 15, a backwash connecting sleeve 16, a backwash retaining ring 17, a backwash spring 18, a packer lower joint 19, a core tube 20 and a return spring 21.

[0043] The external threads on the upper portion of the hydraulic valve sleeve 2 are connected to the internal threads on the lower end of the packer upper connector 1. The top of the hydraulic valve sleeve 2 rests below the inner step of the packer upper connector 1, and the lower end of the packer upper connector 1 rests on the outer step of the hydraulic valve sleeve 2. The internal threads on the upper end of the hydraulic valve sleeve 2 are connected to the external threads on the upper end of the core tube 20.

[0044] The valve body 3 is an annular structure, the center hole of the valve body is axially through and is sleeved on the upper outer periphery of the core tube 20, and the lower inner wall of the center hole of the valve body is provided with a valve body internal thread connected with the upper external thread of the core tube 20.

[0045] An axially penetrating valve body axial channel is provided along the middle of the valve body wall thickness. The valve body axial channel is thin in the middle and thick at both ends. A valve plug 5 is provided in the upper inner cavity of the valve body axial channel. A sealing ring is embedded in the outer periphery of the upper sealing section of the valve plug 5 to achieve sealing with the upper inner wall of the valve body axial channel. A valve plug reduced diameter section 5a is provided on the top of the valve plug 5, and an annular flow space is formed on the outer periphery of the valve plug reduced diameter section 5a; a plug 4 is pressed above the valve plug reduced diameter section 5a, and a sealing ring is embedded in the outer periphery of the lower part of the plug 4 to achieve sealing with the upper inner wall of the valve body axial channel. The upper external thread of the plug 4 is screwed into the upper internal thread of the valve body axial channel.

[0046] A valve body convex ring with an enlarged diameter is provided on the outer periphery of the middle section of the valve body 3. The upper part of the valve body convex ring is located between the inner wall of the hydraulic valve sleeve 2 and the outer wall of the core tube 20. The upper part of the valve body convex ring is provided with an external thread on the valve body. The upper part of the valve body external thread is provided with a valve body plain wall section. The top of the valve body plain wall section abuts against the bottom of the inner step of the hydraulic valve sleeve 2. The upper part of the valve body external thread is connected to the lower internal thread of the hydraulic valve sleeve 2, and the lower end of the hydraulic valve sleeve 2 abuts against the upper part of the valve body convex ring.

[0047] The root of the intersection between the plain wall section of the valve body and the external thread on the valve body is provided with a valve body unsealing water inlet 3a, which communicates with the annular flow space around the outer periphery of the valve plug reduced diameter section 5a. The lower outer wall of the hydraulic valve sleeve 2 is provided with a valve sleeve unsealing water inlet hole 2a, which communicates with the outer end of the valve body unsealing water inlet 3a.

[0048] A downwardly extending valve plug tail rod 5b is provided at the bottom center of the valve plug 5. The valve plug tail rod 5b is inserted into the middle reduced diameter section of the axial channel of the valve body. Axially penetrating tail rod grooves 5c are symmetrically provided on both sides of the valve plug tail rod 5b, serving as an axial flow channel for water.

[0049] The valve body 3 has a seat-sealed water inlet 3b formed on the central inner wall. The inner end of the seat-sealed water inlet 3b communicates with the axial flow passage around the outer periphery of the valve plug stem 5b. The core tube 20 has a core tube water inlet hole 20a that communicates with the outer end of the seat-sealed water inlet 3b. The core tube water inlet hole 20a also serves as the unsealing outlet for the core tube 20.

[0050] A bell-shaped mouth with a downward opening is provided at the lower diameter change part of the axial channel of the valve body, and a valve ball 6 is seated at the bell-shaped mouth. The bottom of the valve ball 6 is supported in the concave arc at the top of the valve support 7. A valve support center rod is provided at the center of the lower end face of the valve support 7. A valve body spring 8 is sleeved on the outer periphery of the valve support center rod. The upper end of the valve body spring 8 rests on the bottom of the valve support 7. The lower end of the valve body spring 8 is supported in the center countersunk hole of the upper end face of the pressure cap 9. The external thread of the pressure cap 9 is screwed into the internal thread of the lower end of the axial channel of the valve body. The center of the pressure cap 9 is provided with a through pressure cap center hole that communicates with the space below.

[0051] The outer wall of the valve body 3 is embedded with an O-ring to seal with the hydraulic chamber sleeve 10, and the inner wall of the valve body 3 is embedded with an O-ring to seal with the outer wall of the core tube 20 to prevent leakage and hydraulic valve failure.

[0052] A lower external thread of the valve body is provided below the convex ring of the valve body, which is connected to the upper internal thread of the hydraulic chamber sleeve 10. The top of the hydraulic chamber sleeve 10 is against the lower outer step of the convex ring of the valve body, and a sealing ring is embedded below the convex ring of the valve body to achieve sealing with the inner wall of the upper port of the hydraulic chamber sleeve 10.

[0053] The movable expansion ring 11 is located in the annular space between the hydraulic chamber sleeve 10 and the core tube 20. The middle section of the hydraulic chamber sleeve 10 is provided with a hydraulic chamber sleeve inner step sealing section with a reduced diameter. The inner wall of the hydraulic chamber sleeve inner step sealing section is embedded with a sealing ring and the middle outer wall of the movable expansion ring 11 to achieve sealing. The middle and lower inner wall of the movable expansion ring 11 is in contact with the outer wall of the core tube 20. The middle inner wall of the movable expansion ring 11 is embedded with a sealing ring and the outer wall of the core tube 20 to achieve sealing.

[0054] The upper end of the movable expansion ring 11 is provided with an outward-bent outer convex ring 11a, the outer wall of the outer convex ring 11a is gap-fitted with the inner wall of the hydraulic chamber sleeve 10, the top of the return spring 21 is supported below the outer convex ring 11a of the movable expansion ring 11, and the bottom of the return spring 21 is supported above the step sealing section inside the hydraulic chamber sleeve.

[0055] A backwash annular cavity is provided below the stepped sealing section in the hydraulic cavity sleeve, and a backwash water inlet 10a is provided on the outer wall of the hydraulic cavity sleeve 10 and communicates with the backwash annular cavity.

[0056] The bottom of the movable expansion ring 11 is provided with an outer conical surface, which abuts against the inner conical surface at the upper end of the support tube 13, facilitating outward compression of the support tube 13. The middle portion of the movable expansion ring 11 is provided with an upper backwash channel 11c extending axially through to the bottom. Four upper backwash channels 11c are evenly spaced around the circumference of the movable expansion ring 11. The upper end of each upper backwash channel 11c is provided with a movable expansion ring radial hole 11b, communicating with the backwash ring cavity.

[0057] A gap is provided between the inner wall of the support tube 13 and the outer wall of the core tube 20 as an annular backwash channel. The self-expanding rubber cylinder 14 is sleeved on the outer periphery of the support tube 13. The upper and lower ends of the self-expanding rubber cylinder 14 are respectively embedded in the limiting end rings 12. The upper limiting end ring 12 is sleeved on the lower outer periphery of the hydraulic chamber sleeve 10 and the top is against the bottom of the outer step of the hydraulic chamber sleeve 10. The lower limiting end ring 12 is sleeved on the outer periphery of the backwash connecting sleeve 16.

[0058] A fixed expansion ring 15 is provided below the support tube 13. The inner conical surface of the upper end of the fixed expansion ring 15 abuts against the inner conical surface below the lower end of the support tube 13. The internal thread of the fixed expansion ring 15 is connected to the external thread of the lower middle part of the core tube 20. The fixed expansion ring 15 is provided with a lower backwash channel 15a that passes through in the axial direction. Four lower backwash channels 15a are evenly arranged along the circumference of the fixed expansion ring 15. The upper end of each lower backwash channel 15a is communicated with the annular backwash channel between the support tube 13 and the core tube 20.

[0059] The movable expansion ring 11 and the fixed expansion ring 15 each have an outer conical surface at one end, which cooperates with the inner conical surface of the support tube 13 to expand the self-expanding rubber cylinder 14. They also have an upper backwash channel 11c and a lower backwash channel 15a, respectively, within them. The openings of the backwash channels have been enlarged to ensure they are as large as possible while meeting strength requirements.

[0060] The support tube 13 has conical inner surfaces at both ends to mate with the expansion rings. A through-hole is also formed around the circumference of the support tube 13. Once the self-expanding rubber cylinder 14 is lowered into place, liquid from the wellbore enters the backwash channel through the open backwash inlet 10a, and then enters the inner layer of the self-expanding rubber cylinder 14 through the small holes in the support tube 13, causing it to expand evenly and efficiently. Slits are intersecting the upper and lower ends of the support tube 13 to facilitate uniform outward expansion of the support tube 13.

[0061] The internal thread of the upper inner wall of the backwash connecting sleeve 16 is connected to the external thread of the fixed expansion ring 15, the upper external thread of the packer lower joint 19 is connected to the lower internal thread of the backwash connecting sleeve 16, and the upper internal thread of the packer lower joint 19 is connected to the lower external thread of the core pipe 20.

[0062] A radially penetrating backwash outlet 16a is provided in the middle and upper part of the backwash connecting sleeve 16, and a backwash baffle ring 17 and a backwash spring 18 are provided in the annular space between the backwash connecting sleeve 16 and the core pipe 20. The lower end of the backwash spring 18 is supported on the top of the lower joint 19 of the packer, and the upper end of the backwash spring 18 is supported below the backwash baffle ring 17. The inner wall of the backwash baffle ring 17 is abutted against the outer wall of the core pipe 20, and the outer wall of the backwash baffle ring 17 is abutted against the inner wall of the backwash connecting sleeve 16 and blocks the inner port of the backwash outlet 16a.

[0063] When the packer is lowered into place, the liquid in the wellbore will enter the backwash channel through the backwash water inlet 10a on the hydraulic chamber sleeve 10, and then enter the inner layer of the self-expanding rubber cylinder 14 through the small holes on the support tube 13, achieving uniform and efficient expansion.

[0064] like Figure 4 As shown, the safety joint of the present invention includes an upper release joint 22, a release shear pin 23, an O-ring 24, a soluble release ring 25, a sealing bushing 26, and a lower release joint 27. The middle outer wall of the release joint 22 is symmetrically provided with downwardly opening grooves. The upper portion of the lower release joint 27 is sleeved onto the outer periphery of the lower portion of the release joint 22, and the upper end is symmetrically provided with upwardly extending tenons 27a. The tenons 27a are inserted into the grooves of the release joint 22 and mate with each other to transmit torque.

[0065] The shoulder of the lower end of the tenon 27a of the lower release joint 27 rests against the lower outer step of the upper release joint 22. The upper circumference of the lower release joint 27 is fixedly connected to the upper release joint 22 by the release shear nails 23. Two O-rings 24 are embedded in the lower outer circumference of the upper release joint 22 to achieve a seal with the upper inner wall of the lower release joint 27.

[0066] The externally threaded upper section of the sealing bushing 26 is connected to the internally threaded lower end of the release joint 22. Below the upper externally threaded section of the sealing bushing 26 is the upper sealing section of the sealing bushing. Two upper sealing rings are embedded in the outer wall of this upper sealing section, which seals against the lower inner wall of the release joint 22. The top of the sealing bushing 26 rests against the lower inner step of the release joint 22, and the sealing bushing 26 is flush with the inner wall of the release joint 22.

[0067] The lower end of the sealing bushing 26 extends downward and is provided with a sealing bushing lower sealing section. The sealing bushing lower sealing section expands outward to form an outer step. Two bushing lower sealing rings are embedded in the outer periphery of the sealing bushing lower sealing section to achieve sealing with the lower inner wall of the lower release joint 27.

[0068] The release joint 22 and the sealing bushing 26 are made of high-strength materials to ensure stability and reliability when subjected to high pressure or large axial load.

[0069] The soluble release ring 25 is located in the annular space between the central inner wall of the lower release joint 27 and the outer wall of the sealing sleeve 26. The top of the soluble release ring 25 abuts the bottom of the upper release joint 22. The inner wall of the upper end of the soluble release ring 25 is a reduced diameter section, the inner circumference of which abuts the central outer circumference of the sealing sleeve 26. An inner step is formed below the reduced diameter section. Below the inner step, the inner wall of the soluble release ring 25 is flush with the lower inner wall of the lower release joint 27, with a gap between it and the central outer wall of the sealing sleeve 26, forming an annular, sealed cavity. The bottom of the soluble release ring 25 abuts the inner step of the lower release joint 27, and the external thread on the lower outer circumference of the soluble release ring 25 connects with the internal thread of the lower release joint 27.

[0070] like Figure 5 As shown, the bypass valve E in the present invention includes a bypass upper joint 28, the lower end of which is threadedly connected to a bypass lower joint 30. The middle section of the bypass lower joint 30 is provided with a plurality of through-flow bypass grooves 30a. The inner cavity of the bypass lower joint 30 is provided with an inner sleeve 29 and is fixed to the bypass lower joint by a pin 29b. The upper end of the inner sleeve 29 is provided with a bell mouth for ball setting. The upper and lower outer circumferences of the inner sleeve 29 are respectively embedded with inner sleeve sealing rings 29a to achieve sealing with the upper and lower inner walls of the bypass lower joint 30.

[0071] Before the ball is dropped, the inner sleeve 29 covers the inner port of the bypass chute 30a, with the upper and lower ends sealed by the inner sleeve seal 29a. When the ball lands in the bell-shaped opening at the upper end of the inner sleeve 29, the accumulated pressure shears the pin 29b, causing the inner sleeve 29 to drop, opening the bypass chute 30a and allowing the oil to enter the outer annulus of the tubing string through the bypass chute 30a.

[0072] like Figure 6As shown, the conversion air anchor of the present invention includes an air anchor upper joint 31, an outer tube 32, a sealing retaining ring 33, a spiral sheet 34, a spiral inner tube 35, a center tube 36, a sliding sleeve 39, a locking ring 41, an air anchor lower joint 42, and a plug 43. The upper end external thread of the center tube 36 is connected to the internal thread of the center hole of the air anchor upper joint 31 and is sealed to the air anchor upper joint 31 via a sealing ring. The upper end internal thread of the outer tube 32 is connected to the lower end external thread of the air anchor upper joint 31. The upper end internal thread of the sealing retaining ring 33 is connected to the upper end external thread of the spiral inner tube 35. The outer wall of the sealing retaining ring 33 is embedded with a sealing ring to seal with the inner wall of the outer tube 32.

[0073] The lower end of the central tube 36 is provided with an enlarged lower externally threaded section, which is connected to the internally threaded lower end of the spiral inner tube 35. The lower end of the spiral inner tube 35 rests on the lower outer step of the central tube 36. The spiral blade 34 is welded to the outer circumference of the spiral inner tube 35. The external threads at the upper end of the air anchor lower joint 42 are connected to the internal threads at the lower end of the outer tube 32.

[0074] The upper end of the sleeve 39 is inserted into the lower port of the center tube 36. The upper part of the sleeve 39 is the upper sealing section of the sleeve. The top of the upper sealing section of the sleeve rests under the second inner step at the lower end of the center tube 36. The upper end of the sleeve 39 is provided with a chamfer that is wider at the top and narrower at the bottom. The inner diameter of the sleeve 39 is smaller than the inner diameter of the center tube 36.

[0075] An O-ring 37 is embedded around the outer periphery of the upper sealing section of the sliding sleeve, sealing it against the lower inner wall of the center tube 36. Below the upper sealing section of the sliding sleeve is a sliding sleeve expansion section, with the outer walls of both the upper sealing section and the expansion section resting against the corresponding inner walls of the center tube 36. The upper outer step of the expansion section of the sliding sleeve rests below the first inner step at the lower end of the center tube 36. Multiple shear pins 38 are evenly distributed along the circumference, each screwed into a threaded hole at the bottom of the center tube 36. The inner end of each shear pin 38 engages a countersunk hole in the outer wall of the expansion section of the sliding sleeve, securing the center tube 36 and the sliding sleeve 39.

[0076] A lower sealing section of the sliding sleeve is provided at the lower part of the sliding sleeve 39. The outer periphery of the lower sealing section of the sliding sleeve is embedded with sealing rings at both ends to achieve sealing with the upper inner wall of the lower air anchor joint 42. Three retaining spring grooves are provided on the circumference below the lower sealing section of the sliding sleeve, and the retaining springs 40 are respectively clamped in the retaining spring grooves of the sliding sleeve 39.

[0077] The internal thread of the lower end of the sliding sleeve 39 is connected to the external thread of the locking ring 41 , the top of the locking ring 41 abuts against the lower inner step of the lower end of the sliding sleeve 39 , and the inner wall of the locking ring 41 is provided with an inner ratchet.

[0078] The central tube 36 serves as a gas or liquid injection channel. When injecting gas or liquid, the upper end of the gas anchor upper joint 31 is connected to the oil pipe, and the lower end of the gas anchor lower joint 42 is connected to the pipe string. The gas anchor serves as a closed gas or liquid injection channel. The gas and liquid enter the lower pipe string through the central tube 36 and are injected into the oil layer.

[0079] The spiral inner tube 35 is used for oil and gas separation. After the gas or liquid intake and discharge is completed, the plug 43 is put into the sleeve 39. After the plug 43 falls into the sleeve 39, the outer ratchet 13a at the lower end of the plug 43 is locked by the inner ratchet of the locking ring 41, so that the plug 43 is combined with the sleeve 39, and the sealing ring on the upper outer periphery of the plug 43 is sealed with the upper inner wall of the sleeve 39.

[0080] By applying pressure to the oil pipe, the plug 43 drives the locking ring 41 and the sleeve 39 to move downward, the shear pin 38 is cut off, and the sleeve 39 moves downward to the lower outer step of the sleeve expansion section and hooks the upper end of the air anchor lower joint 42. The retaining spring 40 reaches below the lower port of the air anchor lower joint 42 and expands, preventing the sleeve 39 from moving upward, and then the pressure is stopped.

[0081] An outer cylinder 32 is designed on the outside of the air anchor, with an outer cylinder liquid inlet 32a and an outer cylinder exhaust hole 32b. The outer cylinder liquid inlet 32a is located below the sealing ring 33, and the annulus between the upper outer wall of the spiral inner tube 35 and the inner wall of the outer cylinder 32 is connected to the outer cylinder liquid inlet 32a.

[0082] The outer tube exhaust hole 32b is located between the top of the sealing ring 33 and the bottom of the air anchor upper joint 31, and the annular space between the inner wall of the spiral inner tube 35 and the outer wall of the central tube 36 is communicated with the outer tube exhaust hole 32b.

[0083] During production, because the injection channel is blocked by plug 43, gas-laden oil flows through outer tube liquid inlet hole 32a on outer tube 32 into the annulus between outer tube 32 and the spiral inner tube. It then flows through the spiral blades and, under the action of centrifugal force, flows closely against the inner wall of outer tube 32 into the annulus between plug 43, sleeve 39, and outer tube 32. It ultimately ascends through the central passage of center tube 36 into the oil pipe and is pumped out. Gas, on the other hand, flows through inner tube air hole 35a on spiral inner tube 35 into the annulus between spiral inner tube 35 and center tube 36, and is ultimately discharged through outer tube air hole 32b on outer tube 32.

[0084] Through the above steps, gas and liquid injection and production can be completed in one trip through the tubing string, which simplifies the operation process, improves construction efficiency, and also improves the oil and gas separation efficiency, thereby increasing oil production and quality.

[0085] The gas-liquid throughput oil production method of the production string of the present invention comprises the following steps in sequence: S1, throw the ball to set the packer C; S2. Inject liquid carbon dioxide or other injection fluid into the oil layer through the rod pump G, conversion gas anchor F, bypass valve E, safety joint D and the central channel of the packer C; S3, soaking the well, when carbon dioxide or injection fluid contacts the crude oil and dissolves in the oil, causing the crude oil to swell and increase its elasticity, while also acting on the relevant components of the crude oil to reduce its viscosity; S4, opening the wellhead to start flowing oil production; S5. After the self-flowing oil production is completed, the ball is thrown to open the bypass valve E; S6, throwing a plugging device to close the bottom channel of the conversion air anchor F; S7. Connect the plunger to the lower part of the sucker rod using a sucker rod coupling or other dedicated connection device to ensure a secure connection to prevent it from becoming disengaged during downhole operation. Then, lower the sucker rod and connected plunger into the well using the sucker rod elevator until the plunger enters the pump barrel of the rod pump G. S8. Start the beam pumping unit on the ground. Under the pumping action of the rod pump G, the oil from the formation enters the annulus above the packer C through the bypass valve E, and then enters the conversion air anchor F from the upper part of the conversion air anchor F for gas-liquid separation. The degassed oil is sent to the wellhead through the rod pump G and the oil pipe H.

[0086] The setting of the packer C in step S1 includes the following sub-steps: S1.1. Apply pressure through the oil pipe, causing water to flow out from the core tube water inlet 20a on the core tube 20 and enter the middle section of the valve body axial channel through the valve body seat seal water inlet 3b; S1.2. Push down the valve ball 6 in the hydraulic valve, allowing water to enter the space above the movable expansion ring 11, pushing the movable expansion ring 11 downward and compressing the return spring 21. S1.3. The outer conical surface at the lower end of the movable expansion ring 11 and the outer conical surface at the upper end of the fixed expansion ring 15 jointly squeeze the support tube 13 to expand evenly outward, achieving mechanical sealing expansion of the self-expanding rubber tube 14. S1.4. After the pressurization is stopped, the hydraulic valve is closed, and the pressure is maintained above the movable expansion ring 11. The self-expanding rubber cylinder 14 absorbs water and continues to expand on the basis of mechanical expansion until it is close to the pipe wall, completing the coupled expansion of mechanical expansion and self-expansion.

[0087] In step S7, after the plunger enters the pump barrel, a pump-up test is typically performed. This involves moving the plunger up and down within the pump barrel several times to check the pump's operation and remove any debris that may be present. After the pump-up test is complete, the anti-surge distance is adjusted according to design requirements to prevent the plunger from colliding with the fixed valve of the rod pump G during operation. After the pump-up test and anti-surge distance adjustment are complete, the wellhead assembly is installed to ensure a leak-proof seal.

[0088] When backwashing is required for packer C in the set state, perform the following steps: A1. Pressurize the oil casing annulus so that water enters the backwash annulus from the backwash water inlet 10a on the hydraulic chamber sleeve 10; A2. Backwash water sequentially passes through the upper backwash channel 11c of the movable expansion ring 11, the gap between the support tube 13 and the core tube 20, and the lower backwash channel 15a of the fixed expansion ring 15; A3. The backwash water pushes the backwash retaining ring 17 to compress the backwash spring 18 and move it downward, opening the backwash outlet 16a on the backwash connecting sleeve 16, and the backwash water flows out from the backwash outlet 16a; A4. The backwash water continues to flow downward into the lower port of the tubing string and returns to the wellhead along the central channel to achieve backwashing.

[0089] When packer C needs to be unsealed, perform the following steps: B1. Pressurize the annulus of the oil casing to allow water to enter through the valve sleeve unsealing water inlet hole 2a on the hydraulic valve sleeve 2; B2. Push the valve plug 5 downward, and the valve plug tail stem 5b at the lower end of the valve plug 5 pushes the valve ball 6 away; B3, water flows out from the core tube water inlet 20a on the core tube 20 to complete the internal pressure relief of the hydraulic valve; B4. The return spring 21 extends, the movable expansion ring 11 returns upward, the support tube 13 and the movable expansion ring 11 lose support, and the seal is released.

[0090] When the packer fails to be unsealed, the following steps are performed: the tubing is lifted to a certain load to cut the release shear nail 23, thereby moving the release joint 22 and the sealing bushing 26 upward together. After the lower outer step of the sealing bushing 26 contacts the upper inner step of the soluble release ring 25, the lower sealing section of the sealing bushing 26 reaches the upper middle part of the soluble release ring 25, so that the lower inner wall of the soluble release ring 25 contacts the well fluid. The soluble release ring 25 will gradually dissolve when immersed in the high-mineralization well fluid, thereby lifting the upper tubing string and then salvaging the lower tubing string to reduce the risk of overhaul.

[0091] The above description is only a preferred embodiment of the present invention, which shows and describes the basic principles, main features and advantages of the present invention, but does not limit the scope of patent protection of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. In addition to the above embodiments, the present invention may have other implementation modes without departing from the spirit and scope of the present invention. The present invention may also have various changes and improvements, and all technical solutions formed by equivalent replacement or equivalent transformation fall within the scope of protection required by the present invention. The scope of protection required by the present invention is defined by the attached claims and their equivalents. Technical features not described in the present invention can be achieved by or using existing technologies, and will not be described here.

Claims

1. A gas-liquid huff-and-puff production string, characterized in that: The invention comprises a guide wire plug (A), a screen tube (B), a packer (C), a safety joint (D), a bypass valve (E), a conversion air anchor (F), a rod pump (G) and an oil pipe (H) connected in sequence from bottom to top, characterized in that: in the conversion air anchor (F), the lower end of the air anchor upper joint (31) is externally threadedly connected to an outer cylinder (32), the lower end of the air anchor upper joint (31) is internally threadedly connected to a center pipe (36), a lower air anchor lower joint (42) is threadedly connected in the lower port of the outer cylinder (32), a sliding sleeve (39) is inserted in the lower port of the center pipe (36) and fixed by a shear nail (38), the lower end of the sliding sleeve (39) is inserted into the center hole of the air anchor lower joint (42) and is connected to a locking ring (41), and the inner wall of the locking ring (41) is provided with an inner ratchet; A spiral inner tube (35) is provided between the central tube (36) and the outer tube (32). The lower end of the spiral inner tube (35) is connected to the outer thread of the lower end of the central tube (36). A spiral sheet (34) is wound around the outer periphery of the spiral inner tube (35). A plurality of inner tube air holes (5a) are provided between the lower spiral sheets (34) and communicate with the inner cavity annulus of the spiral inner tube (35). A sealing retaining ring (33) is screwed on the outer periphery of the upper portion of the spiral inner tube (35). The outer periphery of the sealing retaining ring (33) is sealed with the upper inner wall of the outer tube (32).

2. The gas-liquid huff-and-puff production string according to claim 1, characterized in that: The upper part of the sliding sleeve (39) is the sliding sleeve upper sealing section, and the outer periphery of the sliding sleeve upper sealing section is embedded with an O-ring (37) to seal with the lower inner wall of the center tube (36). The lower part of the sliding sleeve (39) is provided with a sliding sleeve lower sealing section, and the outer periphery of the sliding sleeve lower sealing section is embedded with a sealing ring to achieve sealing with the upper inner wall of the air anchor lower joint (42); a plurality of retaining ring grooves are provided on the circumference below the lower sealing section of the sliding sleeve (39), and a retaining ring (40) is embedded in each retaining ring groove.

3. The gas-liquid huff-and-puff production string according to claim 2, characterized in that: The upper outer step of the sliding sleeve (39) abuts against the lower first inner step of the lower end of the central tube (36), and the upper outer step of the expanded diameter section of the sliding sleeve (39) abuts against the lower second inner step of the lower end of the central tube (36); the upper end of the sliding sleeve (39) is provided with a chamfer that is wider at the top and narrower at the bottom, and the inner diameter of the sliding sleeve (39) is smaller than the inner diameter of the central tube (36).

4. The gas-liquid huff-and-puff production string according to claim 1, characterized in that: The outer cylinder (32) is provided with an outer cylinder liquid inlet hole (32a) and an outer cylinder exhaust hole (32b); the outer cylinder liquid inlet hole (32a) is located below the sealing retaining ring (33); and the outer cylinder exhaust hole (32b) is located between the top of the sealing retaining ring (33) and the bottom of the air anchor upper joint (31).

5. The gas-liquid huff-and-puff production string according to claim 3, characterized in that: The inner diameter of the sliding sleeve (39) matches the outer diameter of the plug (43), and the lower end of the plug (43) is provided with an outer ratchet (43a); after the plug (43) is put into the pipe column and falls into the sliding sleeve (39), the outer ratchet (43a) at the lower end of the plug (43) is locked by the inner ratchet of the locking ring (41); when the shear nail (38) is cut off, the sliding sleeve (39) descends until the bottom of the outer step abuts against the upper end of the air anchor lower joint (42), and the retaining spring (40) reaches below the lower port of the air anchor lower joint (42) and opens, preventing the sliding sleeve (39) from ascending.

6. The gas-liquid huff-and-puff production string according to claim 1, characterized in that: The packer (C) comprises a core tube (20), the upper and lower ends of the core tube (20) are respectively connected to a packer upper joint (1) and a packer lower joint (19), a support tube (13) is sleeved on the outer periphery of the middle section of the core tube (20), a gap is provided between the inner wall of the support tube (13) and the outer wall of the core tube (20) as an annular backwash channel; a self-expanding rubber tube (14) is sleeved on the outer periphery of the support tube (13), and the upper and lower ends of the self-expanding rubber tube (14) are respectively embedded in the limiting end ring (12); The upper and lower ports of the support tube (13) are respectively provided with inner conical surfaces. The inner conical surface of the upper port of the support tube (13) abuts against the lower outer conical surface of the lower end of the movable expansion ring (11). The inner wall of the middle and lower part of the movable expansion ring (11) abuts against the outer wall of the core tube (20) and is sealed with the core tube (20). The inner conical surface of the lower port of the support tube (13) abuts against the upper outer conical surface of the upper end of the fixed expansion ring (15). The inner wall of the fixed expansion ring (15) is screwed onto the external thread section of the middle and lower part of the core tube (20).

7. The gas-liquid huff-and-puff production string according to claim 6, characterized in that: The fixed expansion ring (15) is provided with a plurality of lower backwash channels (15a) extending in the axial direction, and the upper end of each lower backwash channel (15a) is connected to the lower end of the annular backwash channel; the circumference of the movable expansion ring (11) is provided with a plurality of upper backwash channels (11c) extending in the axial direction, and the lower end of each upper backwash channel (11c) is connected to the upper end of the annular backwash channel.

8. The gas-liquid huff-and-puff production string according to claim 7, characterized in that: The movable expansion ring (11) is located in the annular space between the hydraulic cavity sleeve (10) and the core tube (20); the middle section of the hydraulic cavity sleeve (10) is provided with an inner step with a reduced diameter to achieve sealing with the middle outer wall of the movable expansion ring (11); the upper end of the movable expansion ring (11) is provided with an outer convex ring (11a) bent outward, the outer wall of the outer convex ring (11a) is clearance-matched with the inner wall of the hydraulic cavity sleeve (10), and the return spring (21) is supported between the outer convex ring (11a) of the movable expansion ring (11) and the inner step of the hydraulic cavity sleeve (10).

9. The gas-liquid huff-and-puff production string according to claim 8, characterized in that: The upper limiting end ring (12) is sleeved on the lower outer periphery of the hydraulic cavity sleeve (10) and the top thereof abuts against the lower outer step of the hydraulic cavity sleeve (10). The lower limiting end ring (12) is sleeved on the outer periphery of the backwash connecting sleeve (16). The upper inner wall of the backwash connecting sleeve (16) is threadedly connected to the outer wall of the fixed expansion ring (15).

10. The gas-liquid huff-and-puff production string according to claim 8, characterized in that: The upper end of the hydraulic cavity sleeve (10) is connected to the outer wall of the lower end of the hydraulic valve, the lower inner wall of the hydraulic valve is screwed to the outer wall of the core tube (20), and the upper part of the hydraulic valve is embedded between the core tube (20) and the lower inner wall of the hydraulic valve sleeve (2); the upper external thread of the hydraulic valve sleeve (2) is connected to the lower internal thread of the upper joint (1) of the packer, the top of the hydraulic valve sleeve (2) is against the lower inner step of the upper joint (1) of the packer, the lower end of the upper joint (1) of the packer is against the outer step of the hydraulic valve sleeve (2), and the upper internal thread of the hydraulic valve sleeve (2) is connected to the upper external thread of the core tube (20).

11. The gas-liquid huff-and-puff production string according to claim 10, characterized in that: The hydraulic valve comprises an annular valve body (3), the valve body (3) being sleeved on the upper periphery of the core tube (20), and the lower inner wall of the valve body (3) being screwed to the core tube (20); an axially penetrating valve body axial channel is provided along the middle of the valve body wall thickness, and the valve body axial channel is in a shape of being thin in the middle and thick at both ends; a bell mouth opening downward is provided at the lower diameter reducing portion of the valve body axial channel, a valve ball (6) is seated at the bell mouth, and the bottom of the valve ball (6) is supported on the valve support (7) In the concave arc at the top, a valve support center rod is provided at the center of the lower end surface of the valve support (7), and a valve body spring (8) is sleeved on the outer periphery of the valve support center rod. The upper end of the valve body spring (8) abuts against the bottom of the valve support (7), and the lower end of the valve body spring (8) is supported in the center countersunk hole of the upper end surface of the pressure cap (9). The external thread of the pressure cap (9) is screwed into the internal thread of the lower end of the axial channel of the valve body. A through pressure cap center hole is provided in the center of the pressure cap (9) and communicates with the space below.

12. The gas-liquid huff-and-puff production string according to claim 11, characterized in that: The upper inner cavity of the valve body axial channel is provided with a valve plug (5), and the bottom center of the valve plug (5) is provided with a valve plug tail rod (5b) extending downward, and the lower end of the valve plug tail rod (5b) is close to the valve ball (6); the upper part of the valve plug (5) is sealed with the upper inner wall of the valve body axial channel, and the top of the valve plug (5) is provided with a valve plug diameter reduction section (5a), and the outer periphery of the valve plug diameter reduction section (5a) forms an annular flow space, and the upper outer wall of the valve body (3) is provided with a valve body unsealing water inlet (3a) communicating with the annular flow space; a plug (4) is pressed above the valve plug diameter reduction section (5a), and the plug (4) is screwed into the upper port of the valve body axial channel; the lower outer wall of the hydraulic valve sleeve (2) is provided with a valve sleeve unsealing water inlet hole (2a) communicating with the outer port of the valve body unsealing water inlet (3a).

13. The gas-liquid huff-and-puff production string according to claim 12, characterized in that: Axially penetrating tail rod grooves (5c) are symmetrically provided on both sides of the valve plug tail rod (5b) as axial flow passages for water flow; a valve body seat seal water inlet (3b) is provided on the inner wall of the middle portion of the valve body (3) and is communicated with the axial flow passage on the periphery of the valve plug tail rod (5b); and a core tube water inlet hole (20a) is provided on the core tube (20) and is communicated with the outer end of the valve body seat seal water inlet (3b).

14. The gas-liquid huff-and-puff production string according to claim 8, characterized in that: A backwash ring cavity is provided below the inner step sealing section in the middle of the hydraulic cavity sleeve (10), and a backwash water inlet (10a) is provided on the outer wall of the hydraulic cavity sleeve (10) and communicates with the backwash ring cavity; the upper ends of the upper backwash channels (11c) of the movable expansion ring (11) are communicated with the backwash ring cavity through the radial holes (11b) of the movable expansion ring.

15. The gas-liquid huff-and-puff production string according to claim 9, characterized in that: The lower end internal thread of the backwash connecting sleeve (16) is connected to the upper end external thread of the lower joint (19) of the packer, and the upper end internal thread of the lower joint (19) of the packer is connected to the lower end external thread of the core tube (20); a radially penetrating backwash outlet (16a) is provided in the middle and upper part of the backwash connecting sleeve (16), and a backwash retaining ring (17) and a backwash spring (18) are provided in the annular space between the backwash connecting sleeve (16) and the core tube (20), the lower end of the backwash spring (18) is supported on the top of the lower joint (19) of the packer, and the upper end of the backwash spring (18) is supported below the backwash retaining ring (17), the inner wall of the backwash retaining ring (17) is in contact with the outer wall of the core tube (20), and the outer wall of the backwash retaining ring (17) is in contact with the inner wall of the backwash connecting sleeve (16) and blocks the inner port of the backwash outlet (16a).

16. The gas-liquid huff-and-puff production string according to claim 1, characterized in that: The safety connector (D) comprises: The hand-dropping joint (22) has a middle section outer wall symmetrically provided with grooves opening downwards; The lower hand release joint (27) has an upper portion which is sleeved on the outer periphery of the lower portion of the hand release joint (22) and is fixedly connected to the hand release joint (22) via hand release shear nails (23). The upper end is symmetrically provided with tenons, each tenon being embedded in a groove of the hand release joint (22); A sealing bushing (26) having an upper external thread section connected to an internal thread at the lower end of the release upper joint (22), a lower outer wall of the upper external thread section being sealed to an inner wall at the lower end of the release upper joint (22), and a lower end of the sealing bushing (26) being enlarged to form an outer step and sealing to an inner wall at the lower end of the release lower joint (27); The soluble hand release ring (25) is located in the annular space between the middle inner wall of the lower hand release joint (27) and the outer wall of the sealing sleeve (26), the inner peripheral wall of the upper end of the hand release ring abuts against the middle outer peripheral wall of the sealing sleeve (26), a gap is left between the inner wall below the upper inner step and the middle outer wall of the sealing sleeve (26) and the hand release ring is flush with the lower inner wall of the lower hand release joint (27), and the outer thread of the lower outer periphery of the soluble hand release ring (25) is connected with the inner thread above the inner step of the lower hand release joint (27).

17. The gas-liquid huff-and-puff production string according to claim 16, characterized in that: The top of the soluble release ring (25) abuts against the bottom of the release upper joint (22), and the bottom of the soluble release ring (25) abuts against the inner step of the release lower joint (27); the top of the sealing bushing (26) abuts against the lower inner step of the release upper joint (22), and the sealing bushing (26) is flush with the inner wall of the release upper joint (22).

18. The gas-liquid huff-and-puff production string according to claim 1, characterized in that: The bypass valve (E) includes a bypass upper joint (28), the lower end of the bypass upper joint (28) is screwed with a bypass lower joint (30), the middle section of the bypass lower joint (30) is provided with a plurality of through bypass flow grooves (30a), the inner cavity of the bypass lower joint (30) is provided with an inner sleeve (29) and is fixed to the bypass lower joint by a pin (29b), the upper end of the inner sleeve (29) is provided with a bell mouth for ball setting, and the upper and lower outer peripheries of the inner sleeve (29) are respectively embedded with inner sleeve sealing rings (29a) to achieve sealing with the upper and lower inner walls of the bypass lower joint (30).

19. A gas-liquid throughput oil production method using an oil production string, characterized in that: The method of using the gas-liquid huff-and-puff production string as claimed in claim 1 includes the following steps in sequence: S1. Throw the ball to set the packer (C); S2, injecting gas or liquid into the oil layer through the rod pump (G), conversion gas anchor (F), bypass valve (E), safety joint (D) and the central channel of the packer (C); S3, soaking the well to reduce the viscosity of crude oil; S4, opening the wellhead to start flowing oil production; S5, throw the ball to open the bypass valve (E); S6. Throw a plug to close the bottom channel of the conversion air anchor (F); S7. Connect the plunger to the lower part of the sucker rod and lower the sucker rod and the connected plunger into the well using the sucker rod elevator until the plunger enters the pump barrel of the rod pump (G). S8. Start the pumping unit on the ground. Under the pumping action of the rod pump (G), the oil from the formation enters the annulus above the packer (C) through the bypass valve (E), and then enters the conversion air anchor (F) from the upper part to separate the gas and liquid. The degassed oil is sent to the wellhead through the rod pump (G) and the oil pipe (H).

20. The gas-liquid huff-and-puff production string according to claim 19, characterized in that: The setting of the packer (C) in step S1 includes the following sub-steps: S1.

1. Apply pressure through the oil pipe to make water flow out from the core tube water inlet hole (20a) on the core tube (20) and enter the middle section of the valve body axial channel through the valve body seat seal water inlet (3b); S1.

2. Push the valve ball (6) in the hydraulic valve downward, allowing water to enter the space above the movable expansion ring (11), pushing the movable expansion ring (11) downward and compressing the return spring (21); S1.

3. The outer conical surface of the lower end of the movable expansion ring (11) and the outer conical surface of the upper end of the fixed expansion ring (15) jointly squeeze the support tube (13) to expand evenly outward, thereby achieving mechanical sealing expansion of the self-expanding rubber tube (14); S1.

4. After the pressurization is stopped, the hydraulic valve is closed, and the pressure is maintained above the movable expansion ring (11). The self-expanding rubber cylinder (14) absorbs water and continues to expand on the basis of mechanical expansion until it is close to the pipe wall, completing the coupled expansion of mechanical expansion and self-expansion.

21. The gas-liquid huff-and-puff production string according to claim 19, characterized in that: When the packer needs to be backwashed in the set state, perform the following steps: A1. Pressurize the oil casing annulus to allow water to enter the backwash annulus through the backwash water inlet (10a) on the hydraulic chamber sleeve (10); A2, backwash water passes through the upper backwash channel (11c) of the movable expansion ring (11), the gap between the support cylinder (13) and the core tube (20), and the lower backwash channel (15a) of the fixed expansion ring (15) in sequence; A3. The backwash water pushes the backwash retaining ring (17) to compress the backwash spring (18) and move it downward, opening the backwash outlet (16a) on the backwash connecting sleeve (16), and the backwash water flows out from the backwash outlet (16a); A4. The backwash water continues to flow downward into the lower port of the tubing string and returns to the wellhead along the central channel to achieve backwashing.

22. The gas-liquid huff-and-puff production string according to claim 19, characterized in that: When the packer needs to be unsealed, perform the following steps: B1. Pressurize the annulus of the oil casing to allow water to enter through the valve sleeve unsealing water inlet hole (2a) on the hydraulic valve sleeve (2); B2. Push the valve plug (5) downward, and the valve plug tail rod (5b) at the lower end of the valve plug (5) pushes the valve ball (6) away; B3, water flows out from the core tube water inlet (20a) on the core tube (20) to complete the internal pressure relief of the hydraulic valve; B4. The return spring (21) stretches, the movable expansion ring (11) returns upward, the support cylinder (13) and the movable expansion ring (11) lose support, and unsealing is achieved.

23. The gas-liquid huff-and-puff production string according to claim 22, characterized in that: When the packer fails to be unsealed, the following steps are performed: the pipe string is lifted to a certain load, the release shear nail (23) is cut off, so that the release joint (22) and the sealing bushing (26) are moved upward together, and after the lower outer step of the sealing bushing (26) contacts the upper inner step of the soluble release ring (25), the lower sealing section of the sealing bushing (26) reaches the upper middle part of the soluble release ring (25), so that the lower inner wall of the soluble release ring (25) contacts the well fluid, and the soluble release ring (25) will gradually dissolve when immersed in the high-mineralization well fluid, thereby raising the upper pipe string and then salvaging the lower pipe string.

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