Carbon dioxide airtight packer

Abstract

The invention relates to the technical field of carbon dioxide airtight packers, in particular to a carbon dioxide airtight packer which comprises a central pipe, the upper end of the central pipe is fixedly connected with the inner side of the lower end of an upper connector, and the central pipe is sequentially sleeved with a piston, a sealing assembly, a guide ring, an upper cone, a slip mechanism and a lower cone from top to bottom. The sealing assembly can expand and seal and has hardness gradient, a lock ring sleeve is installed on the outer side of the lower end of the upper connector through a starting pin and a lock ring, the lock ring sleeve is matched with the lock ring through teeth, and the upper end of the piston is fixedly connected with the lower end of the lock ring sleeve. The sealing device is reasonable and compact in structure and convenient to use, and by arranging the sealing assembly with the hardness gradient, the sealing performance when the sealing assembly is extruded and the stability of the whole structure can be guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of packers, and is a carbon dioxide airtight packer. Background Art

[0002] Substantially, carbon dioxide geological storage is to compress carbon dioxide gas to the supercritical state and inject it into the underground formation with appropriate sealing conditions for long-term storage and isolation, so as to reduce the carbon dioxide emissions in the atmosphere within a period of time and slow down the trends of global warming and deterioration of the earth's environment.

[0003] In carbon dioxide geological storage, injection wells and production wells are usually also provided. The captured carbon dioxide is injected into the formation through the injection wells, and at the same time, the corresponding fluid in the formation migrates and is discharged from the production wells. In order to prevent leakage, similar to using a packer to isolate the producing formation to prevent the leakage of produced fluid or injected fluid in an oil well, a packer is also used in geological storage to seal the annular space between the pipe string and the wellbore and between the pipe strings to isolate the storage formation.

[0004] With the continuous expansion and extension of the oil exploration and development field, the proportion of complex oil and gas reservoirs and difficult-to-produce reserves is increasing. Considering the characteristics of low-porosity, low-permeability, and extremely thick oil layers, the steam injection process for heavy oil thermal recovery needs to be considered, and it is necessary to ensure that the packer has strong resistance to bidirectional pressure difference. However, the sealing assembly of the conventional packer has poor application effect in the high-pressure gas injection environment, and the sealing assembly has become a shortcoming, and there may be leakage points due to processing problems during use. Summary of the Invention

[0005] The present invention provides a carbon dioxide airtight packer, which overcomes the deficiencies of the above-mentioned prior art and can effectively solve the problem that the sealing assembly of the existing packer has poor application effect in the high-pressure gas injection environment.

[0006] The technical solution of the present invention is achieved by the following measures: A carbon dioxide airtight packer includes a central tube. The upper end of the central tube is fixedly connected to the inner side of the lower end of the upper joint. A piston, a sealing assembly, a guide ring, an upper cone, a slip mechanism, and a lower cone are sequentially sleeved on the central tube from top to bottom. The sealing assembly can expand and seal, and the assembly has a hardness gradient. The outer side of the lower end of the upper joint is provided with a lock ring sleeve through a starting pin and a lock ring. The lock ring sleeve is engaged with the lock ring through teeth. The upper end of the piston is fixedly connected to the lower end of the lock ring sleeve. A pressure transmission hole is provided on the central tube at the upper end position of the piston. The lower end of the guide ring is fixedly connected to the upper end of the upper cone. The slip mechanism is fixedly connected to the lower end of the upper cone through a first shear pin. The lower end of the slip mechanism is fixedly connected to the lower cone through a second shear pin. The lower end of the lower cone is fixedly connected to the upper end of the ratchet sleeve. The lower end of the ratchet sleeve is fixedly connected to the upper end of the lower joint. The middle part of the ratchet sleeve is sleeved on the outer circle of the ratchet. The upper end of the ratchet is fixedly connected to the lower end of the central tube. A release ring is installed at the inner circle inlet of the lower end of the ratchet through a release pin. The lower end of the release ring is positioned by the inner circle step at the upper end of the lower joint.

[0007] The following is a further optimization and / or improvement of the above-mentioned invention technical solution: Preferably, the sealing assembly includes an upper rubber cylinder, an upper back ring, an upper support ring, a middle rubber cylinder, a lower support ring, a lower back ring, and a lower rubber cylinder that are sequentially sleeved on the central tube from top to bottom. The upper rubber cylinder, the upper back ring, and the upper support ring are symmetrically arranged on both sides of the middle rubber cylinder with the lower support ring, the lower back ring, and the lower rubber cylinder.

[0008] Preferably, the upper rubber cylinder and the lower rubber cylinder adopt a high-hardness hydrogenated nitrile rubber vulcanized 316L stainless steel wire mesh and copper support ring forming structure.

[0009] Preferably, the upper back ring and the lower back ring adopt an integrally die-cast aluminum bronze material, which has ductility and toughness.

[0010] Preferably, the upper support ring and the lower support ring adopt a modified polytetrafluoroethylene material added with carbon brazing and graphite, and its hardness is higher than that of the upper rubber cylinder, the lower rubber cylinder, and the middle rubber cylinder.

[0011] Preferably, the middle rubber cylinder is made of a modified hydrogenated nitrile material, with both ends vulcanized and embedded with a coil spring. The rubber hardness at both ends of the vulcanized part is slightly higher than the middle hardness. The middle rubber cylinder is matched with the upper support ring and the lower support ring through an inclined surface. The annular groove on the inner surface of the middle rubber cylinder is a preset compression compensation position, and the M-shaped ring groove on the outer surface divides the sealing surface into multiple segments. The contact width and contact stress are more uniform when the M-shaped ring groove on the outer surface contacts the inner wall of the casing after compression.

[0012] Preferably, the slips mechanism includes a slips sleeve, slips and a spring. The upper end of the slips sleeve is fixedly connected to the lower end of the upper cone through a first shear pin, and the lower end of the slips sleeve is fixedly connected to the upper end of the lower cone through a second shear pin. The slips and the spring are arranged between the slips sleeve and the outer wall of the central tube; or / and, the lower sub is threadedly connected to the ratchet sleeve and fixed by a fastening screw. The lower sub is sealed with the ratchet sleeve through a sixth O-ring; the lock ring sleeve is sealed with the connecting joint through a first O-ring; the piston is sealed with the lock ring sleeve through a second O-ring, and the piston is sealed with the central tube through a third O-ring; the ratchet sleeve is sealed with the ratchet through a fourth O-ring; the ratchet is sealed with the central tube through a fifth O-ring.

[0013] The structure of the present invention is reasonable and compact, and it is convenient to use. By setting a sealing component with a hardness gradient, the sealing performance of the sealing component when being extruded and the stability of the overall structure can be ensured. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] FIG Figure 1 is a schematic diagram of the main view semi-sectional structure of an embodiment of the present invention.

[0015] FIG Figure 2 is the enlarged structural schematic diagram of the upper half part in FIG Figure 1 FIG

[0016] FIG Figure 3 is the enlarged structural schematic diagram of the lower half part in FIG Figure 1 FIG

[0017] FIG Figure 4 is the enlarged structural schematic diagram after the sealing component rotates to the horizontal direction.

[0018] The codes in the drawings are respectively: 1. upper sub; 2. starting pin; 3. first O-ring; 4. lock ring sleeve; 5. lock ring; 6. second O-ring; 7. piston; 8. third O-ring; 9. sealing component; 91. upper rubber cylinder; 92. upper back ring; 93. upper support ring; 94. middle rubber cylinder; 95. lower support ring; 96. lower back ring; 97. lower rubber cylinder; 10. central tube; 11. guide ring; 12. upper cone; 13. slips sleeve; 14. first shear pin; 15. slips; 16. spring; 17. second shear pin; 18. lower cone; 19. ratchet sleeve; 20. fourth O-ring; 21. fifth O-ring; 22. ratchet; 23. fastening screw; 24. sixth O-ring; 25. releasing pin; 26. releasing ring; 27. lower sub. DETAILED DESCRIPTION OF THE INVENTION

[0019] The present invention is not limited by the following embodiments, and the specific implementation manners can be determined according to the technical solutions of the present invention and actual situations.

[0020] In the present invention, for the convenience of description, the relative positional relationship of each component is described according to the layout mode of the accompanying drawings of the specification. For example, the positional relationships such as front, rear, upper, lower, left, and right are determined according to the layout direction of the accompanying drawings of the specification. Figure 1 The layout mode of the accompanying drawings is used for description. For example, the positional relationships such as front, rear, upper, lower, left, and right are determined according to the layout direction of the accompanying drawings of the specification.

[0021] The present invention will be further described below in conjunction with embodiments and the accompanying drawings: Embodiment 1: As shown in Figures 1-4 the figure, the carbon dioxide airtight packer includes a central tube 10. The upper end of the central tube 10 is fixedly connected to the inner side of the lower end of the upper joint 1. A piston 7, a sealing assembly 9, a guide ring 11, an upper cone 12, a slip mechanism, and a lower cone 18 are sequentially sleeved on the central tube 10 from top to bottom. The sealing assembly 9 can expand and seal and the assembly has a hardness gradient. A lock ring sleeve 4 is installed on the outer side of the lower end of the upper joint 1 through a starting pin 2 and a lock ring 5. The lock ring sleeve 4 and the lock ring 5 are in tooth engagement. The upper end of the piston 7 is fixedly connected to the lower end of the lock ring sleeve 4. A pressure transmission hole is provided on the central tube 10 at the upper end position of the piston 7. The lower end of the guide ring 11 is fixedly connected to the upper end of the upper cone 12. The slip mechanism is fixedly connected to the lower end of the upper cone 12 through a first shear pin 14. The lower end of the slip mechanism is fixedly connected to the lower cone 18 through a second shear pin 17. The lower end of the lower cone 18 is fixedly connected to the upper end of the ratchet sleeve 19. The lower end of the ratchet sleeve 19 is fixedly connected to the upper end of the lower joint 27. The middle part of the ratchet sleeve 19 is sleeved on the outer circle of the ratchet 22. The upper end of the ratchet 22 is fixedly connected to the lower end of the central tube 10. A release ring 26 is installed at the inner circle inlet of the lower end of the ratchet 22 through a release pin 25. The lower end of the release ring 26 is positioned by the inner circle step at the upper end of the lower joint 27.

[0022] The usage process of the present invention is as follows: Setting packer: When using the present invention, a ball seat is connected to the lower part, or the running tool itself has a ball seat. A ball is dropped onto the ball seat and pump pressure is applied. The pressure passes through the pressure transmission hole in the upper part of the central tube 10 to push the piston 7 downward. The piston 7 is threadedly connected to the lock ring sleeve 4. When the pressure reaches the starting pressure, the piston 7 drives the lock ring sleeve 4 to cut off the starting pin 2 and continues to move downward. The piston 7 pushes the sealing assembly 9, the guide ring 11, and the upper cone 12 downward, cuts off the first shear pin 14, and pushes the slip mechanism to transmit force to act on the lower cone 18, cuts off the second shear pin 17. The slip mechanism expands towards the casing, bites the casing tightly, the sealing assembly 9 expands and seals the casing, and the lock ring sleeve 4 locks the lock ring 5 upward under the push of the piston 7 to prevent the sealing assembly 9 from rebounding, thus completing the setting of the packer; Releasing packer: A special release tool is lowered into the lower joint 27, and then the release ring 26 is pulled upward until the release pin 25 is cut off. The release ring 26 moves upward to the bottom end of the milled groove of the ratchet 22, driving the central tube 10 to move upward together. The elastic claws of the ratchet 22 retract. The central tube 10 drives the upper joint 1 and the lock ring 5 to move upward until the lock ring sleeve 4 and the piston 7 are driven to move upward. The sealing assembly 9 rebounds and the slip mechanism retracts, thus completing the release of the packer.

[0023] According to actual needs, the above-mentioned carbon dioxide airtight packer can be further optimized and / or improved as follows: Example 2: As shown in Figure 1 , 2 , and Figure 4, the sealing assembly 9 includes an upper rubber cylinder 91, an upper back ring 92, an upper support ring 93, an intermediate rubber cylinder 94, a lower support ring 95, a lower back ring 96, and a lower rubber cylinder 97 that are sequentially sleeved on the central tube 10 from top to bottom. The upper rubber cylinder 91, the upper back ring 92, and the upper support ring 93 are symmetrically arranged on the upper and lower sides of the intermediate rubber cylinder 94 with the lower support ring 95, the lower back ring 96, and the lower rubber cylinder 97. The upper rubber cylinder 91, the upper back ring 92, and the upper support ring 93 are made of different materials to form different hardness gradients. When the sealing assembly 9 is squeezed, it can maintain the sealing performance after sufficient compression of the intermediate rubber cylinder 94 and the stability of the overall structure. The sealing assembly 9 is used in an airtight environment containing high-concentration carbon dioxide and is particularly suitable for processes such as injecting critical carbon dioxide and sealing layer gas production with low temperature requirements.

[0024] Example 3: As shown in Figure 4 , the upper rubber cylinder 91 and the lower rubber cylinder 97 are formed by vulcanizing a high-hardness hydrogenated nitrile rubber with a 316L stainless steel wire mesh and a copper support ring. The internal wire mesh can significantly improve the strength, wear resistance, and fatigue resistance of the upper rubber cylinder 91 and the lower rubber cylinder 97. The copper support ring can maintain the overall structure of the end rubber cylinder. The upper rubber cylinder 91 and the lower rubber cylinder 97 play a role in shoulder protection against collision and preventing premature setting when the packer is lowered and during large-displacement circulation.

[0025] Example 4: As shown in Figure 4 , the upper back ring 92 and the lower back ring 96 are made of integrally die-cast aluminum bronze material, which has ductility and toughness. This setting can prevent the end rubber cylinder from being overly folded after being squeezed and deformed, ensuring uniform expansion of the end rubber cylinder and the intermediate rubber cylinder 94.

[0026] Example 5: As shown in Figure 4 , the upper support ring 93 and the lower support ring 95 are made of modified polytetrafluoroethylene material added with carbon brazing and graphite, and their hardness is higher than that of the upper rubber cylinder 91, the lower rubber cylinder 97, and the intermediate rubber cylinder 94. The upper support ring 93 and the lower support ring 95 made of modified polytetrafluoroethylene material added with carbon brazing and graphite have excellent corrosion resistance and temperature resistance in a carbon dioxide environment, and their hardness is higher than that of the end rubber cylinder and the intermediate rubber cylinder, playing a major role in maintaining the structure and supporting the setting of the entire sealing system.

[0027] Example 6: As shown in Figure 4As shown, the middle rubber cylinder 94 is made of modified hydrogenated nitrile material, vulcanized at both ends and embedded with a ring of springs. The rubber hardness at both ends of the vulcanized part is slightly higher than that in the middle. The middle rubber cylinder 94 is matched with the upper support ring 93 and the lower support ring 95 through inclined planes. The annular groove on the inner surface of the middle rubber cylinder 94 is the preset compression compensation position, and the M-shaped ring groove on the outer surface divides the sealing surface into multiple segments. There is a ring of spring protection structure embedded at both ends by vulcanization to maintain the balance and uniform expansion of the middle rubber cylinder 94 and provide auxiliary resilience when the packer is released; the annular groove on the inner surface is the preset compression compensation position to prevent the middle rubber cylinder 94 from arching and losing stability when being squeezed or the gap extrusion at the joint with the central pipe 10. The M-shaped ring groove on the outer surface divides the sealing surface into multiple segments, and the contact width and contact stress are more uniform when contacting the inner wall of the casing after compression.

[0028] Example 7: As shown in the appendix Figure 3 As shown, the slip mechanism includes a slip sleeve 13, slips 15 and a spring 16. The upper end of the slip sleeve 13 is fixedly connected to the lower end of the upper cone 12 through a first shear pin 14, and the lower end of the slip sleeve 13 is fixedly connected to the upper end of the lower cone 18 through a second shear pin 17. The slips 15 and the spring 16 are arranged between the slip sleeve 13 and the outer wall of the central pipe 10. During setting, the slips 15 are pushed, and the slips 15 drive the slip sleeve 13 to transmit force to act on the lower cone 18, cutting the second shear pin 17. The slips 15 expand towards the casing, compressing the spring 16 and biting tightly on the casing; during release, the slips 15 retract, pushing the slip sleeve 13 and the upper cone 12 to move upward.

[0029] Example 8: As shown in the appendix Figures 1-4 As shown, the lower sub 27 is threadedly connected to the ratchet sleeve 19 and fixed by a fastening screw 23. The lower sub 27 is sealed with the ratchet sleeve 19 through a sixth O-ring 24; the lock ring sleeve 4 is sealed with the connecting sub 1 through a first O-ring 3; the piston 7 is sealed with the lock ring sleeve 4 through a second O-ring 6, and the piston 7 is sealed with the central pipe 10 through a third O-ring 8; the ratchet sleeve 19 is sealed with the ratchet 22 through a fourth O-ring 20; the ratchet 22 is sealed with the central pipe 10 through a fifth O-ring 21. By setting the fastening screw 23, the connection thread between the lower sub 27 and the ratchet sleeve 19 is prevented from loosening, and by setting the O-rings, the sealing performance is enhanced to ensure the pressure retention during pump pressure setting.

[0030] The above technical features respectively constitute the embodiments of the present invention, which have strong adaptability and implementation effects. Non-essential technical features can be added or reduced according to actual needs to meet the requirements of different situations.

Claims

1. A carbon dioxide airtight packer, characterized in that It includes a central tube. The upper end of the central tube is fixedly connected to the inner side of the lower end of the upper joint. A piston, a sealing assembly, a guide ring, an upper cone, a slip mechanism, and a lower cone are successively sleeved on the central tube from top to bottom. The sealing assembly can expand and seal, and the assembly has a hardness gradient. A lock ring sleeve is installed on the outer side of the lower end of the upper joint through a starting pin and a lock ring. The lock ring sleeve and the lock ring are engaged by teeth. The upper end of the piston is fixedly connected to the lower end of the lock ring sleeve. A pressure transmission hole is provided on the central tube at the upper end position of the piston. The lower end of the guide ring is fixedly connected to the upper end of the upper cone. The slip mechanism is fixedly connected to the lower end of the upper cone through a first shear pin. The lower end of the slip mechanism is fixedly connected to the lower cone through a second shear pin. The lower end of the lower cone is fixedly connected to the upper end of the ratchet sleeve. The lower end of the ratchet sleeve is fixedly connected to the upper end of the lower joint. The middle part of the ratchet sleeve is sleeved on the outer circle of the ratchet. The upper end of the ratchet is fixedly connected to the lower end of the central tube. A release ring is installed at the inner circle inlet of the lower end of the ratchet through a release pin. The lower end of the release ring is positioned by the inner circle step at the upper end of the lower joint.

2. The carbon dioxide airtight packer according to claim 1, wherein The sealing assembly includes an upper rubber cylinder, an upper back ring, an upper support ring, a middle rubber cylinder, a lower support ring, a lower back ring, and a lower rubber cylinder that are successively sleeved on the central tube from top to bottom. The upper rubber cylinder, the upper back ring, and the upper support ring are symmetrically arranged on both sides of the middle rubber cylinder with the lower support ring, the lower back ring, and the lower rubber cylinder.

3. The carbon dioxide airtight packer according to claim 2, wherein The upper rubber cylinder and the lower rubber cylinder are formed by vulcanizing high-hardness hydrogenated nitrile rubber with 316L stainless steel wire mesh and a copper support ring.

4. The carbon dioxide airtight packer according to claim 2 or 3, characterized in that The upper back ring and the lower back ring are made of integrally die-cast aluminum bronze material, which has ductility and toughness.

5. The carbon dioxide airtight packer according to claim 2 or 3, characterized in that The upper support ring and the lower support ring are made of modified polytetrafluoroethylene material added with carbon brazing and graphite, and their hardness is higher than that of the upper rubber cylinder, the lower rubber cylinder, and the middle rubber cylinder.

6. The carbon dioxide airtight packer according to claim 4, wherein The upper support ring and the lower support ring are made of modified polytetrafluoroethylene material added with carbon brazing and graphite, and their hardness is higher than that of the upper rubber cylinder, the lower rubber cylinder, and the middle rubber cylinder.

7. The carbon dioxide airtight packer according to claim 2 or 3 or 6, characterized in that The middle rubber cylinder is made of modified hydrogenated nitrile material. Both ends are vulcanized and embedded with a spring. The rubber hardness at both ends of the vulcanized part is slightly higher than the middle hardness. The middle rubber cylinder cooperates with the upper support ring and the lower support ring through an inclined surface. The annular groove on the inner surface of the middle rubber cylinder is a preset compression compensation position, and the M-shaped ring groove on the outer surface divides the sealing surface into multiple segments.

8. The carbon dioxide airtight packer according to claim 4, characterized in that The middle rubber cylinder is made of modified hydrogenated nitrile material. Both ends are vulcanized and embedded with a spring. The rubber hardness at both ends of the vulcanized part is slightly higher than the middle hardness. The middle rubber cylinder cooperates with the upper support ring and the lower support ring through an inclined surface. The annular groove on the inner surface of the middle rubber cylinder is a preset compression compensation position, and the M-shaped ring groove on the outer surface divides the sealing surface into multiple segments.

9. The carbon dioxide airtight packer according to claim 5, characterized in that The middle rubber cylinder is made of modified hydrogenated nitrile material. Both ends are vulcanized and embedded with a spring. The rubber hardness at both ends of the vulcanized part is slightly higher than the middle hardness. The middle rubber cylinder cooperates with the upper support ring and the lower support ring through an inclined surface. The annular groove on the inner surface of the middle rubber cylinder is a preset compression compensation position, and the M-shaped ring groove on the outer surface divides the sealing surface into multiple segments.

10. The carbon dioxide airtight packer according to claim 1 or 2 or 3 or 6 or 8 or 9, characterized in that The slip mechanism includes a slip sleeve, slips and a spring. The upper end of the slip sleeve is fixedly connected to the lower end of the upper cone through a first shear pin, and the lower end of the slip sleeve is fixedly connected to the upper end of the lower cone through a second shear pin. The slips and the spring are arranged between the slip sleeve and the outer wall of the central tube; or / and, the lower sub is threadedly connected to the ratchet sleeve and fixed by a fastening screw. The lower sub is sealed with the ratchet sleeve through a sixth O-ring; the lock ring sleeve is sealed with the connecting sub through a first O-ring; the piston is sealed with the lock ring sleeve through a second O-ring, and the piston is sealed with the central tube through a third O-ring; the ratchet sleeve is sealed with the ratchet through a fourth O-ring; the ratchet is sealed with the central tube through a fifth O-ring.

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