Carbon dioxide injection sealing assembly

Abstract

A carbon dioxide injection sealing assembly belongs to downhole operation tools in the petroleum industry, is used for downhole carbon dioxide injection, and particularly relates to a carbon dioxide injection sealing assembly structure of a salvageable intubation bridge plug. The utility model provides a carbon dioxide injection sealing assembly which can solve the problems that after an underground tool is used for injecting carbon dioxide, the underground tool cannot be pulled out, and long-term sealing is achieved. The device is characterized in that an upper joint is in threaded connection with an insertion tube, a back cap is in threaded connection with a sealing cylinder, a gasket, a first combined seal, a baffle ring and a second combined seal are arranged in the sealing cylinder, and a guide sleeve is in threaded connection with the sealing cylinder. The upper pressing ring is in threaded connection with the sealing cylinder. The rubber cylinder, the spacer ring and the pressing ring are sleeved on the rubber cylinder shaft; and the rubber cylinder shaft is in threaded connection with the sealing cylinder.

Description

Technical Field

[0001] The utility model belongs to a downhole operation tool of the petroleum industry and is used for injecting carbon dioxide downhole, in particular to a carbon dioxide injection sealing assembly structure of a retrievable intubation bridge plug. Background Art

[0002] Carbon dioxide flooding is a technical approach to increasing oilfield production. Injecting CO2 into reservoirs effectively reduces crude oil viscosity, lowers residual oil saturation, dissolves colloids in the reservoir, and significantly improves oil recovery. However, CO2 injection wells place higher demands on downhole tools. CO2 is highly corrosive to downhole tools and is prone to scaling. When conventional tools are lowered into the well for CO2 injection, scaling can form between moving parts and between the tool and casing. This can lead to excessive loading on the string, string breakage, and major repairs, impacting well production and wasting significant manpower and financial resources. Conventional tools are made of ordinary steel that is unsuitable for CO2 injection. The corrosive nature of CO2 can easily lead to tool seal failure. During CO2 injection and shut-off, significant temperature differences can cause tubing expansion and contraction, potentially de-sealing the tool. This can lead to annular pressure buildup, jeopardizing well safety and damaging the casing. Loss of sealing requires pulling the string and re-running the tool, impacting production schedules. Utility Model Content

[0003] The utility model aims at solving the above problems and provides a carbon dioxide injection sealing assembly which can solve the problems of downhole tools being unable to be removed and being sealed for a long time after being used for carbon dioxide injection.

[0004] In order to achieve the above-mentioned purpose of the utility model, the utility model adopts the following technical solutions, the utility model includes an upper joint, a cannula, a guide sleeve, a gasket, a first combination seal, a first retaining ring, a second combination seal, a back cap, a sealing cylinder, an upper pressure ring, a rubber cylinder, a spacer ring, a de-sealing sleeve, a lower pressure ring, a shear pin seat, a rubber cylinder shaft, an upper cone, an upper locking spring, a slip cover, a slip, a slip spring, a center tube, a lower cone, a lower locking spring, a slip cover back cap, a seat seal piston, a cylinder, a first block, a starting piston, a connecting sleeve, a lower back cap, and a lower sleeve. , guide shoe, resistance sleeve, hanging sleeve, ball seat, second clamping block, support sleeve, second retaining ring, seat sealing shear nail, falling shear nail, throwing shear nail, steel ball, lower liquid inlet hole, starting shear nail, upper liquid inlet hole, unsealing shear nail, characterized in that: the upper joint is threadedly connected to the cannula, the back cap is threadedly connected to the sealing cylinder, the gasket, the first combination seal, the retaining ring, and the second combination seal are installed in the sealing cylinder, the guide sleeve is threadedly connected to the sealing cylinder; the upper pressure ring and the sealing cylinder are threadedly connected; the rubber cylinder, the spacer ring, and the lower pressure ring are sleeved on the rubber cylinder shaft, and the rubber cylinder shaft is threadedly connected to the sealing cylinder The shear pin seat is threadedly connected to the rubber cylinder shaft, the unsealing shear pin is fixed between the unsealing sleeve and the shear pin seat, and the unsealing sleeve supports the upper end thread of the center tube; the upper cone and the lower pressure ring are threadedly connected; the upper locking spring is installed in the groove of the upper cone, and the slip cover is hung on the upper cone; the slip is installed in the slip cover, and the slip spring is fixed between the slip and the slip cover; the lower cone is installed on the center tube and is limited between the slip cover back cap and the slip, and the lower locking spring is installed in the groove of the lower cone; the slip cover back cap and the slip cover are threadedly connected; the piston is threadedly connected to the lower cone; the first clamping block is inserted into The seat seal piston cooperates with the groove of the center tube, the starting piston is pressed on the first clamping block, and the starting shearing pin is installed between the seat seal piston and the starting piston; the cylinder is sleeved on the seat seal piston and the starting piston; the connecting sleeve is threadedly connected to the center tube; the second clamping block is installed in the resistance sleeve, the support sleeve is sleeved on the resistance sleeve, the support sleeve cooperates with the second clamping block, and the resistance sleeve is threadedly connected to the insert pipe; the ball seat is sleeved in the resistance sleeve to support the second clamping block and the resistance sleeve; the shearing pin is installed between the support sleeve and the resistance sleeve; the seat seal shearing pin is installed between the ball seat and the resistance sleeve.

[0005] As a preferred solution of the utility model, the hanging sleeve is sleeved on the cannula, and the shear pin is installed between the hanging sleeve and the cannula; the second retaining ring is threadedly connected to the resistance sleeve.

[0006] As another preferred solution of the present invention, the cannula sealing stroke is set to 3000 mm.

[0007] The beneficial effects of the utility model are as follows: 1. Tool seating and gas injection are completed in one trip through the tubing string, and the structure of the process tubing string is simple.

[0008] 2. Under normal circumstances, when the tubing string is pulled out, the downhole bridge plug can be pulled out of the well together with the tubing string.

[0009] 3. The seal between the cannula and the bridge plug can ensure reliable long-term gas injection sealing.

[0010] 4. The plug has a release function. When the bridge plug cannot be pulled out, the oil pipe in the well can be safely pulled out of the well.

[0011] 5. During the bridge plug seating process and when the pipe string is injected with gas and creeps, the seal between the cannula and the bridge plug will not be lost. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a structural diagram of the present utility model.

[0013] Figure 2 yes Figure 1 Magnified view of part A.

[0014] Figure 3 yes Figure 1 Enlarged view of part B.

[0015] Figure 4 yes Figure 1 Enlarged view of part C.

[0016] Figure 5 yes Figure 1 Enlarged view of part D. DETAILED DESCRIPTION

[0017] The utility model comprises an upper joint 1, a cannula 2, a guide sleeve 3, a gasket 4, a first combined seal 5, a retaining ring 6, a second combined seal 7, a back cap 8, a sealing cylinder 9, an upper pressure ring 10, a rubber cylinder 11, a spacer ring 12, an unsealing sleeve 13, a lower pressure ring 14, a shear pin seat 15, a rubber cylinder shaft 16, an upper cone 17, an upper locking spring 18, a slip cover 19, a slip 20, a slip spring 21, a center tube 22, a lower cone 23, a lower locking spring 24, a slip The back cap 25 of the tile cover, the sealing piston 26, the cylinder 27, the first clamping block 28, the starting piston 29, the connecting sleeve 30, the lower back cap 31, the lower sleeve 32, the guide shoe 33, the resistance sleeve 34, the hanging sleeve 35, the ball seat 36, the second clamping block 37, the support sleeve 38, the retaining ring 39, the sealing shear pins 40, the shear pins 41 for shearing off, the shear pins 42 for shearing off, the steel ball 43, the lower liquid inlet 44, the starting shear pins 45, the upper liquid inlet 46, and the releasing shear pins 47 are arranged in a specific embodiment: the upper joint 1 is threadedly connected to the cannula 2, the back cap 8 is threadedly connected to the sealing sleeve 9, the gasket 4, the first combination seal 5, the retaining ring 6, and the second combination seal 7 are installed in the sealing sleeve 9, and the guide sleeve 3 is threadedly connected to the sealing sleeve 9. The upper pressure ring 10 is threadedly connected to the sealing sleeve 9. The rubber sleeve 11, the spacer ring 12, and the lower pressure ring 14 are sleeved on the rubber sleeve shaft 16, and the rubber sleeve shaft 16 is threadedly connected to the sealing sleeve 9. The shear pin holder 15 is threadedly connected to the rubber cylinder shaft 16. The unsealing shear pin 47 is fixed between the unsealing sleeve 13 and the shear pin holder 15. The unsealing sleeve 13 supports the upper end thread of the center tube 22. The upper cone 17 is threadedly connected to the lower pressure ring 14. The upper locking spring 18 is installed in the groove of the upper cone 17, and the slip cover 19 is hung on the upper cone 17. The slip 20 is installed in the slip cover 19, and the slip spring 21 is fixed between the slip 20 and the slip cover 19. The lower cone 23 is installed on the center tube 22 and is limited between the slip cover back cap 25 and the slip 20. The lower locking spring 24 is installed in the groove of the lower cone 23. The slip cover back cap 25 and the slip cover 19 are threadedly connected. The piston 26 is threadedly connected to the lower cone 23. The first clamping block 28 is inserted into the sealing piston 26 and cooperates with the groove of the central tube 22. The starting piston 29 is pressed against the first clamping block 28, and the starting shear pin 45 is installed between the sealing piston 26 and the starting piston 29. The cylinder 27 is sleeved on the sealing piston 26 and the starting piston 29. The connecting sleeve 30 is threadedly connected to the central tube 22. The second clamping block 37 is installed in the resistance sleeve 34, and the support sleeve 38 is sleeved on the resistance sleeve 34. The support sleeve 38 cooperates with the second clamping block 37, and the resistance sleeve 34 is threadedly connected to the insert 2. The ball seat 36 is sleeved in the resistance sleeve 34, supporting the second clamping block 37 and the resistance sleeve 34. The shear pin 41 is installed between the support sleeve 38 and the resistance sleeve 34. The sealing shear pin 40 is installed between the ball seat 36 and the resistance sleeve 34.

[0018] As a preferred solution of the present invention, the hanging sleeve 35 is sleeved on the cannula 2, and the shear pin 42 is installed between the hanging sleeve 35 and the cannula 2; the retaining ring 39 and the resistance sleeve 34 are threadedly connected.

[0019] As another preferred solution of the present invention, the cannula sealing stroke is set to 3000 mm.

[0020] The utility model is lowered into the well as a whole. After the well is sealed, the bottom ball seat is knocked off and carbon dioxide is injected from the lower end of the tool to protect the upper casing. After the sealing is completed, there is no connection between the cannula and the bridge plug. The cannula can provide compensation for the creep of the pipe string during the gas injection process. The specific operation process is to connect the airtight sealing oil pipe through the upper joint 1 of the retrievable cannula bridge plug and lower it into the well. After the retrievable bridge plug reaches the designed position, the steel ball 43 is put in. After the steel ball 43 is sent to the ball seat 36 with clean water, the pipe is pressurized. The pressure is transmitted to the starting piston 29 through the lower liquid inlet hole 44, the annulus between the cannula 2 and the center pipe 22, and the upper liquid inlet hole 46. The starting piston 29 moves downward, shearing the starting shear pin 45. The first clamping block 28 is separated from the matching groove with the center pipe 22. The sealing piston 26 pushes the lower cone 23 upward to anchor the slip 20 on the casing, and the lower locking spring 24 is locked with the center pipe 22. As the pressure in the tubing increases, the steel ball 43 and ball seat 36 descend together, shearing the sealing shear pins 40. The second clamping block 37 and resistance sleeve 34 lose the support of the ball seat 36, and the second clamping block 37 disengages from the mating groove with the support sleeve 38. Under the pressure, the steel ball 43, ball seat 36, retaining ring 39, support sleeve 38, lower back cap 31, lower sleeve 32, center tube 22, sealing tube 9, and upper pressure ring 10 descend together, pushing the upper cone 17 into the slip 20 and compressing the rubber sleeve 11 until it rises to the casing wall. The upper locking spring 18 locks with the center tube 22, and the sealing is complete. When the pressure in the tubing reaches the sealing pressure, the shear pins 41 are sheared off, and the steel ball 43, ball seat 36, retaining ring 39, second clamping block 37, and resistance sleeve 34 fall to the bottom of the artificial wellbore, opening the gas injection channel. Gas injection begins. There is no connection between the upper joint 1 and the cannula 2 and the bridge plug, and the body of the cannula 2 forms a seal with the first combined seal 5 and the second combined seal 7 in the sealing cylinder 9 .

[0021] To release the bridge plug, the tubing is lifted, driving the upper connector 1, cannula 2, and hanging sleeve 35 upward. When hanging sleeve 35 hooks onto the unsealing sleeve 13, the upward force from the tubing shears the unsealing shear pins 47, with a shearing force of 80-100 kN. The unsealing sleeve 13 hooks onto the rubber sleeve shaft 16, separating the rubber sleeve shaft 16 from the central pipe 22. The rubber sleeve shaft 16 then pulls the sealing sleeve 9 and upper pressure ring 10 upward, releasing the rubber sleeve 11. The rubber sleeve shaft 16 hooks onto the lower pressure ring 14 and upper cone 17, withdrawing the upper cone 17 from the slips 20. The upper cone 17 hooks onto the slip cover 19, which pulls the slips 20 out of the lower cone 23. The tool is completely unsealed, and all remaining components are lifted out of the well along with the tubing.

[0022] If the lifting tonnage is too large and the seal cannot be released, the shear pins 42 between the hanging sleeve 35 and the cannula 2 will shear off after exceeding the tonnage it can withstand, with a shear force of 180-200 kN, and the hanging sleeve 35 will be separated from the cannula 2. The upper connector 1 and cannula 2 are lifted out of the well along with the oil pipe, and then a special fishing tool is lowered to mate with the unsealing sleeve 13 for active release.

[0023] Technical parameters of drillable intubation bridge plug: 1. Maximum outer diameter of tool: Φ114mm.

[0024] 2. Minimum inner diameter of tool: Φ55mm.

[0025] 3. Working temperature: ≤120℃.

[0026] 4. Working pressure: ≤50MPa.

[0027] 5. Applicable casing: Φ121mmΦ126mm.

[0028] 6. Unsealing force: 80100kN.

[0029] 7. Throwing force: 180200kN.

[0030] It can be understood that the above specific description of the present invention is only used to illustrate the present invention and is not limited to the technical solutions described in the embodiments of the present invention. Ordinary technicians in this field should understand that the present invention can still be modified or replaced by equivalents to achieve the same technical effects; as long as the use requirements are met, they are within the scope of protection of the present invention.

Claims

1. Carbon dioxide injection seal assembly, including upper joint (1), insert (2), guide sleeve (3), gasket (4), first combination seal (5), first retaining ring (6), second combination seal (7), back cap (8), sealing cylinder (9), upper pressure ring (10), rubber cylinder (11), spacer ring (12), unsealing sleeve (13), lower pressure ring (14), shear pin seat (15), rubber cylinder shaft (16), upper cone (17), upper locking spring (18), slip cover (19), slip (20), slip spring (21), center tube (22), lower cone (23), lower locking spring (24), Slip cover back cap (25), seat seal piston (26), cylinder (27), first clamping block (28), starting piston (29), connecting sleeve (30), lower back cap (31), lower sleeve (32), guide shoe (33), resistance sleeve (34), hanging sleeve (35), ball seat (36), second clamping block (37), support sleeve (38), second retaining ring (39), seat seal shear nail (40), shear nail (41), shear nail (42), steel ball (43), lower liquid inlet hole (44), starting shear nail (45), upper liquid inlet hole (46), unsealing shear nail (47); characterized in that: The upper joint (1) is threadedly connected to the insert (2), the back cap (8) is threadedly connected to the sealing cylinder (9), the gasket (4), the first combined seal (5), the first retaining ring (6), and the second combined seal (7) are installed in the sealing cylinder (9), and the guide sleeve (3) is threadedly connected to the sealing cylinder (9); the upper pressure ring (10) is threadedly connected to the sealing cylinder (9); the rubber cylinder (11), the spacer ring (12), and the lower pressure ring (14) are sleeved on the rubber cylinder shaft (16), and the rubber cylinder shaft (16) is threadedly connected to the sealing cylinder (9); the shear nail seat (15) is threadedly connected to the rubber cylinder shaft (16) , the unsealing shear nail (47) is fixed between the unsealing sleeve (13) and the shear nail seat (15), and the unsealing sleeve (13) supports the upper end thread of the center tube (22); the upper cone (17) and the lower pressure ring (14) are threadedly connected; the upper locking spring (18) is installed in the groove of the upper cone (17), and the slip cover (19) is hung on the upper cone (17); the slip (20) is installed in the slip cover (19), and the slip spring (21) is fixed between the slip (20) and the slip cover (19); the lower cone (23) is installed on the center tube (22), limited to the slip cover back cap (25) and The lower locking spring (24) is installed in the groove of the lower cone (23); the slip cover back cap (25) and the slip cover (19) are threadedly connected; the piston (26) and the lower cone (23) are threadedly connected; the first clamping block (28) is inserted into the sealing piston (26) and matched with the groove of the center tube (22); the starting piston (29) is pressed on the first clamping block (28), and the starting shear pin (45) is installed between the sealing piston (26) and the starting piston (29); the cylinder (27) is sleeved on the sealing piston (26) and the starting piston (29); the connecting sleeve (30) and the center tube (22) are threadedly connected; the second clamping block (37) is installed in the resistance sleeve (34), the support sleeve (38) is sleeved on the resistance sleeve (34), the support sleeve (38) cooperates with the second clamping block (37), and the resistance sleeve (34) is threadedly connected to the cannula (2); the ball seat (36) is sleeved in the resistance sleeve (34) to support the second clamping block (37) and the resistance sleeve (34); the shear nail (41) is installed between the support sleeve (38) and the resistance sleeve (34); the seat seal shear nail (40) is installed between the ball seat (36) and the resistance sleeve (34).

2. The carbon dioxide injection sealing assembly according to claim 1, characterized in that: The hanging sleeve (35) is sleeved on the cannula (2), and the shear nail (42) is installed between the hanging sleeve (35) and the cannula (2); the second retaining ring (39) and the resistance sleeve (34) are threadedly connected.

3. The carbon dioxide injection sealing assembly according to claim 1, characterized in that: The cannula sealing stroke is set to 3000mm.

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