Novel casing annulus packer

Abstract

The invention discloses a novel casing annulus packer, which relates to the technical field of petroleum and natural gas extraction well completion tools, and comprises a central pipe, the lower end of the central pipe is in threaded connection with a lower joint, the upper end of the central pipe is in threaded connection with a lower piston, and the top end of the lower piston is in threaded connection with an upper piston and an upper joint in sequence; the upper piston and the lower piston are in threaded connection with the two ends of the sleeve through the upper connector and the lower connector, a center pipe pressure transmitting hole is formed in the top end of the center pipe, the outer wall of the lower piston and the outer wall of the upper piston are sleeved with a lower piston outer cylinder and an upper piston outer cylinder which are in threaded connection, and the center pipe is provided with a rubber cylinder lower support through a shear pin and provided with a double-rubber-cylinder sealing assembly through the rubber cylinder lower support. Pressure in the sleeve can be transmitted into a lower piston inner cavity and an upper piston inner cavity through a central pipe pressure transmission hole and a lower piston pressure transmission hole in the central pipe respectively, and a lower piston outer cylinder and an upper piston outer cylinder are pushed to move downwards under the action of the pressure; and the lower piston outer cylinder is used for sealing the inner wall of the sleeve by extruding the double-rubber-cylinder sealing assembly.

Description

Technical Field

[0001] The invention relates to the technical field of oil and natural gas exploitation and completion tools, and in particular to a novel casing annulus packer. Background Art

[0002] In a wellbore environment with multiple challenges such as complex geological structures, coexistence of multiple pressure systems in the same open hole section, and large temperature differences, ensuring cementing quality has become a difficult task. In particular, the problem of casing annulus gas blowby is frequent and difficult. In order to significantly improve the cementing quality and sealing reliability, a casing external packer is usually connected to the middle section of the casing. This measure can effectively ensure the cementing quality and greatly improve the sealing performance of the wellbore, thereby ensuring the safety and efficiency of oil and gas production.

[0003] At present, the casing annulus packer has a simple structural design and weak functionality, and it is difficult to fully adapt to the complex and changeable wellbore environment. For example, the casing annulus packer described in the application publication number CN105569604A is only designed to cope with the emergency well shut-in control when the high-pressure gas layer fluid rushes up during the waiting stage, and lacks the ability to provide reliable isolation throughout the entire life cycle. Although the casing annulus packer involved in the authorization announcement number CN207131367U has a sealing function, it cannot achieve the anchoring and straightening functions when the force between the casing changes, thereby increasing the risk of cement ring crushing, cracking, and separation of the cement ring and the casing bonding surface. In order to overcome these shortcomings of the prior art, a new type of casing annulus packer is designed. The packer is designed to solve the problem that traditional casing packers cannot simultaneously achieve straightening, anchoring and reliable sealing during cement cementing, thereby providing a more comprehensive and efficient technical guarantee for cementing operations. Summary of the invention

[0004] The purpose of the present invention is to provide a novel casing annulus packer, which can solve the problems of simultaneously realizing straightening, anchoring and reliable sealing of the casing packer during cementing.

[0005] The technical solution of the present invention is achieved in this way: The top of the lower piston is threadedly connected to the upper piston and the bottom of the piston is threadedly connected to the piston. The upper end of the piston is threadedly connected to the piston and the upper joint in sequence, and the two ends of the casing are threadedly connected through the upper joint and the lower joint. The top of the central tube is provided with a central tube pressure transmission hole that can transmit the fluid pressure in the casing, and the outer walls of the lower piston and the upper piston are sleeved with a threaded lower piston outer cylinder and an upper piston outer cylinder, so that a lower piston inner cavity is formed between the central tube and the lower piston outer cylinder, and an upper piston inner cavity is formed between the upper piston outer cylinder and the lower piston. A rubber cylinder lower support is installed on the central tube through a shear pin, and a double rubber cylinder sealing assembly is provided through the rubber cylinder lower support, so that the pressure in the casing can be transmitted to the lower piston inner cavity and the upper piston inner cavity respectively through the central tube pressure transmission hole and the lower piston pressure transmission hole on the central tube, and the lower piston outer cylinder and the upper piston outer cylinder are pushed downward under the action of pressure, so that the lower piston outer cylinder can squeeze the double rubber cylinder sealing assembly to achieve sealing of the inner wall of the casing.

[0006] Furthermore, a slip support is threadedly connected to the top end of the central tube near the lower joint, and a slip assembly engaging with the inner wall of the casing is provided between the slip support and the lower support of the rubber cylinder.

[0007] Furthermore, the slip assembly includes a slip lower connecting rod movably connected to the upper end of the slip support through a plurality of first mounting grooves arranged in an annular manner; The bottom end of the rubber cylinder lower support is movably connected with a slip upper connecting rod matched with the slip lower connecting rod through a plurality of second mounting grooves, and a toothed slip is connected between the slip lower connecting rod and the slip upper connecting rod through a pin shaft.

[0008] Furthermore, the meshing teeth on two adjacent toothed slips are in opposite directions.

[0009] Furthermore, a straightening mechanism capable of straightening the casing is provided at the bottom end of the slip support through a lower joint.

[0010] Furthermore, the righting mechanism comprises a righting support threadedly connected to the bottom end of the lower joint, a righting slip ring is provided between the righting support and the slip support via the lower joint sleeve, and the righting slip ring is abutted against the slip support via a wave spring.

[0011] Furthermore, the righting mechanism also includes a righting assembly arranged between the righting support and the righting slip ring; the righting assembly includes a righting lower connecting rod movably connected to the top of the righting support through a third mounting groove, the bottom end of the righting slip ring is connected to a righting upper connecting rod corresponding to the righting lower connecting rod through a pin shaft, and a righting slider is movably connected between the righting upper connecting rod and the righting lower connecting rod through a pin shaft.

[0012] Furthermore, roller mounting grooves are provided at both ends of the straightening slider, and rollers are installed through the roller mounting grooves in cooperation with pins. A straightening middle connecting rod connected to a straightening support through a pin is provided between the two rollers on the straightening slider.

[0013] Furthermore, the casing annulus packer also includes a locking ring with an annular opening, the inner wall of the locking ring is provided with fine teeth matching with the first ratchet teeth on the outer wall of the upper piston, and the outer wall is provided with coarse teeth matching with the second ratchet teeth on the outer tube of the locking ring.

[0014] Furthermore, the outer wall of the bottom end of the locking ring outer tube is threadedly connected to the upper piston outer tube.

[0015] The beneficial effects of the present invention are as follows: the present invention ensures the righting effect and low friction resistance during the lowering process through a three-link righting mechanism, and ensures the performance of bidirectional anchoring by adopting a double-link anchoring, and ensures the life of the rubber cylinder and the sealing reliability by adopting a double-rubber cylinder sealing component covered with a nickel-based alloy shoulder guard, and ensures sufficient setting force by adopting a double-piston setting seal while reducing the radial size of the packer to ensure the cementing efficiency of the cement slurry, and ensures the rapid locking performance after setting and the reliability of long-term locking by a locking ring and a locking ring outer cylinder, thereby providing more comprehensive and long-term technical guarantees for cementing operations. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 is a schematic diagram of a casing annulus packer; Figure 2 It is an overall cross-sectional view of the casing annulus packer in working state; Figure 3 is a half-section view of the center tube; Figure 4 is a half-section view of the lower piston; Figure 5 is a half-section view of the lower piston outer cylinder; Figure 6 is a half-section view of the upper piston outer cylinder; Figure 7 is a half-section view of the upper piston; Figure 8 for Figure 2 The enlarged view of point A in the middle; Fig. 9 for Figure 2 The enlarged view of point B in the middle; Fig.10 It is a half-section view of the toothed slip support; Fig.11 It is the axonometric view of the righting slide; Fig.12 It is an axonometric view of the toothed slip; Fig.13 It is a half-section view of the lower support of the rubber cylinder; Fig.14 It is a half-section view of the righting support; Fig.15 is an axonometric view of the lock ring; Fig.16 It is a half-section view of the outer cylinder of the lock ring; Fig.17 for Figure 2 Enlarged view of point C in the middle.

[0018] Description of the drawings: 1. Lower joint; 2. Righting support; 3. Double rubber cylinder sealing assembly; 4. Righting lower connecting rod; 6. Righting middle connecting rod; 7. Roller; 8. Righting slider; 9. Righting upper connecting rod; 10. Righting sliding ring; 11. Wave spring; 12. Slip support; 13. Slip lower connecting rod; 14. Toothed slip; 15. Slip upper connecting rod; 16. Rubber cylinder lower support; 17. Shear pin; 21. Center tube; 23. Lower piston outer cylinder; 24. Lower piston; 25. Upper piston outer cylinder; 26. Upper piston; 27. Lock Ring outer tube; 28, locking ring; 29, upper joint; 34, third mounting groove; 36, roller mounting groove; 42, first mounting groove; 46, bite teeth; 47, second mounting groove; 54, center tube pressure transmission hole; 57, lower piston outer tube guide hole; 61, lower piston pressure transmission hole; 65, cement slurry guide hole; 69, first ratchet; 72, second ratchet; 73, fine teeth; 74, coarse teeth; 77, lower piston inner cavity; 78, lower piston outer cavity; 79, upper piston inner cavity; 80, upper piston outer cavity; 81, cement locking cavity. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0020] In the description of the present invention, it is necessary to understand that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0021] See attached Figure 1-Figure 17 The novel casing annulus packer according to the embodiment of the present invention comprises a central tube 21, the lower end of the central tube 21 is threadedly connected with a lower joint 1, the upper end is threadedly connected with a lower piston 24, the top end of the lower piston 24 is threadedly connected with an upper piston 26 and an upper joint 29 in sequence, and the two ends of the casing are threadedly connected through the upper joint 29 and the lower joint 1, and the top end of the central tube 21 is provided with a central tube pressure transmission hole 54 capable of transmitting the fluid pressure in the casing. The outer walls of the lower piston 24 and the upper piston 26 are sleeved with a threaded lower piston outer cylinder 23 and an upper piston outer cylinder 25, so that a lower piston inner cavity 77 is formed between the central tube 21 and the lower piston outer cylinder 23, and an upper piston inner cavity 79 is formed between the upper piston outer cylinder 25 and the lower piston 24, and a rubber tube lower support 16 is installed on the central tube 21 through a shear pin 17, and a double rubber tube sealing assembly 3 is provided through the rubber tube lower support 16.

[0022] When the casing annulus packer is lowered to the designated position and the cementing operation is completed, the rubber plug is lowered to clean the cement slurry on the inner wall of the casing and realize the pressure holding operation in the casing. The pressure in the casing is transmitted to the lower piston inner cavity 77 and the upper piston inner cavity 79 through the central tube pressure transmission hole 54 on the central tube 21 and the lower piston pressure transmission hole 61 on the lower piston 24, respectively, and the lower piston outer cylinder 23 and the upper piston outer cylinder 25 are pushed downward by the pressure, so that the lower piston outer cylinder 23 can squeeze the double rubber cylinder sealing assembly 3 to achieve the sealing of the inner wall of the casing.

[0023] It should be noted that when the pressure in the casing is transmitted to the lower piston inner cavity 77 and the upper piston inner cavity 79 respectively through the center tube pressure transmission hole 54 on the center tube 21 and the lower piston pressure transmission hole 61 on the lower piston 24, the fluid in the lower piston outer cavity 78 formed between the lower piston 24 and the lower piston outer tube 23 can be discharged through the lower piston outer tube guide hole 57 on the lower piston outer tube 23 to prevent the pressure from being blocked and hindering the sealing.

[0024] like Figure 2 , Figure 8 , Fig.10 , Fig.12 and Fig.13 As shown, in order to improve the anchoring effect on the sleeve and avoid changes in the sleeve force. A slip support 12 is threadedly connected to the top of the center pipe 21 near the lower joint 1, and a slip assembly that engages with the inner wall of the sleeve is provided between the slip support 12 and the lower support 16 of the rubber cartridge. Specifically, the slip assembly includes a slip lower connecting rod 13 movably connected to the upper end of the slip support 12 through a plurality of first mounting grooves 42 arranged in an annular manner; the lower end of the lower support 16 of the rubber cartridge is movably connected to a slip upper connecting rod 15 adapted to the slip lower connecting rod 13 through a plurality of second mounting grooves 47, and a toothed slip 14 is connected between the slip lower connecting rod 13 and the slip upper connecting rod 15 through a pin shaft. Preferably, the directions of the engaging teeth 46 on two adjacent toothed slips 14 are opposite.

[0025] Specifically, the lower piston outer cylinder 23 and the upper piston outer cylinder 25 will gradually squeeze the double rubber cylinder sealing assembly 3 during the downward movement, and further squeeze the lower rubber cylinder support 16 to cut off the shear pin 17. After the shear pin 17 is cut off, the lower rubber cylinder support 16 pushes the toothed slip 14 to extend and engage the casing through the slip upper connecting rod 15, thereby realizing the bidirectional anchoring of the packer. After the anchoring is completed, the lower piston outer cylinder 23 and the upper piston outer cylinder 25 will further squeeze the double rubber cylinder sealing assembly 3 during the downward movement, so that the axial dimension of the double rubber cylinder sealing assembly 3 is compressed and the radial dimension is increased, and finally the inner wall of the casing is squeezed to achieve sealing. Among them, the opposite and alternating arrangement of the engaging teeth 46 on the toothed slip 14 realizes the axial bidirectional anchoring of the packer. At the same time, compared with the inclined support design adopted by the traditional slip, it reduces the number of pins and avoids sliding friction loss, thereby improving the transmission efficiency of the slip setting process.

[0026] like Figure 1 , Figure 2 , Fig. 9 , Fig.10 , Fig.11 and Fig.14 As shown, in order to make the axis of the packer parallel and ensure the straightening effect, the present application is provided with a straightening mechanism capable of straightening the casing at the bottom end of the slip support 12 through the lower joint 1, the straightening mechanism comprises a straightening support 2 threadedly connected to the bottom end of the lower joint 1, a straightening slip ring 10 is sleeved between the straightening support 2 and the slip support 12 through the lower joint 1, and the straightening slip ring 10 is abutted against the slip support 12 through a wave spring 11.

[0027] A righting assembly is arranged between the righting support 2 and the righting slip ring 10, and the righting assembly includes a righting lower connecting rod 4 movably connected to the top of the righting support 2 through a third mounting groove 34, and a righting upper connecting rod 9 corresponding to the righting lower connecting rod 4 is connected to the bottom of the righting slip ring 10 through a pin shaft, and a righting slider 8 is movably connected between the righting upper connecting rod 9 and the righting lower connecting rod 4 through a pin shaft, roller mounting grooves 36 are provided at both ends of the righting slider 8, and rollers 7 are installed through the roller mounting grooves 36 and the pin shafts, and a righting middle connecting rod 6 connected to the righting support 2 through a pin shaft is provided between the two rollers 7 on the righting slider 8.

[0028] When the casing annulus packer is working, the lower joint 1 and the upper joint 29 are respectively connected to the two ends of the casing and are lowered together with the casing. During the lowering process, the wave spring 11 will squeeze the upper straightening connecting rod 9 and the straightening slider 8 through the straightening sliding ring 10, so that the roller 7 on the straightening slider 8 is always in contact with the casing, which plays a role in straightening and reducing friction. Specifically, the present application designs a three-link straightening mechanism and adopts a circumferentially equidistant arrangement, wherein both ends of the straightening lower connecting rod 4 and the straightening middle connecting rod 6 are connected to the straightening support 2 and the straightening slider 8 to form a parallelogram structure, ensuring that the straightening slider 8 always remains parallel to the axis of the packer to ensure the straightening effect. In addition, the upper straightening connecting rod 9 is connected to the straightening sliding ring 10 to squeeze the wave spring 11, and the high elastic modulus of the wave spring 11 provides a strong straightening force, and the roller 7 for reducing friction is designed on the straightening slider 8, which ensures the low friction resistance of the packer during the lowering process.

[0029] like Figure 7 , Fig.15 , Fig.16 and Fig.17 As shown, in order to enable the cement to solidify and further lock the packer, and finally achieve the casing annulus sealing effect. The casing annulus packer in the present application also includes a locking ring 28 with an annular opening, the inner wall of the locking ring 28 is provided with fine teeth 73 that match the first ratchet teeth 69 on the outer wall of the upper piston 26, and the outer wall is provided with coarse teeth 74 that match the second ratchet teeth 72 on the locking ring outer tube 27, and the outer wall of the bottom end of the locking ring outer tube 27 is threadedly connected with the upper piston outer tube 25.

[0030] During the downward extrusion process, the lower piston outer tube 23 and the upper piston outer tube 25 will drive the lock ring outer tube 27 to move downward. Among them, the lock ring 28 and the second ratchet 72 on the lock ring outer tube 27 are meshed with coarse teeth 74, and the meshing teeth are deep, and the radial clearance cannot meet the requirements of mutual tooth skipping between the coarse teeth 74 structures. The lock ring 28 and the first ratchet 69 on the outer wall of the upper piston 26 are meshed with fine teeth 73, and the meshing teeth are shallow, and the radial clearance can meet the requirements of mutual tooth skipping between the fine teeth 73 structures. Therefore, the lock ring outer tube 27 drives the lock ring 28 to move downward, and during the movement, it meshes with the first ratchet 69 on the outer wall of the upper piston 26 to prevent retreat. When the pressure in the casing decreases, the packer will not be unsealed under the locking action of the locking ring 28. At the same time, cement slurry flows into the upper piston outer chamber 80 (between the upper piston outer chamber 25 and the upper piston 26) and the cement locking chamber 81 (between the upper piston 26 and the locking ring outer chamber 27) through the cement slurry guide hole 65 of the upper piston outer tube 25. As time goes by, the cement solidifies and further locks the packer, ultimately achieving the sealing effect of the casing annulus.

[0031] It should be noted that the double rubber cylinder sealing assembly 3 includes two rubber cylinders, which are fixedly connected by a spacer ring. In addition, the rubber cylinder is coated with a nickel-based alloy shoulder guard, which plays a role in coating the rubber core during setting to reduce the shoulder protrusion of the rubber core structure and damage to the rubber core. At the same time, the shoulder guard plays a role in isolating the corrosive formation fluid after deformation, so that the performance of the rubber cylinder is not affected by the formation fluid and the service life is guaranteed. The design of the double sealing rubber cylinder ensures the reliability of the seal.

[0032] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A novel casing annulus packer, comprising a center pipe (21), wherein the lower end of the center pipe (21) is threadedly connected to a lower joint (1), and the upper end is threadedly connected to a lower piston (24), and the top end of the lower piston (24) is threadedly connected to an upper piston (26) and an upper joint (29) in sequence, and the two ends of the casing are threadedly connected through the upper joint (29) and the lower joint (1), and the top end of the center pipe (21) is provided with a center pipe pressure transmission hole (54) capable of transmitting the fluid pressure in the casing, characterized in that: The outer walls of the lower piston (24) and the upper piston (26) are sleeved with a threaded lower piston outer cylinder (23) and an upper piston outer cylinder (25), so that a lower piston inner cavity (77) is formed between the center tube (21) and the lower piston outer cylinder (23), and an upper piston inner cavity (79) is formed between the upper piston outer cylinder (25) and the lower piston (24). A rubber cylinder lower support (16) is installed on the center tube (21) via a shear pin (17), and a double rubber cylinder sealing assembly (3) is provided via the rubber cylinder lower support (16), so that the pressure in the casing can be transmitted to the lower piston inner cavity (77) and the upper piston inner cavity (79) respectively through the center tube pressure transmission hole (54) and the lower piston pressure transmission hole (61) on the center tube (21), and the lower piston outer cylinder (23) and the upper piston outer cylinder (25) are pushed downward under the action of pressure, so that the lower piston outer cylinder (23) can squeeze the double rubber cylinder sealing assembly (3) to achieve sealing of the inner wall of the casing.

2. A novel casing annulus packer according to claim 1, characterized in that: A slip support (12) is threadedly connected to the top end of the central tube (21) near the lower joint (1), and a slip assembly engaging with the inner wall of the casing is provided between the slip support (12) and the rubber sleeve lower support (16).

3. A novel casing annulus packer according to claim 2, characterized in that: The slip assembly comprises a slip support (12) whose upper end is movably connected to a slip lower connecting rod (13) through a plurality of first mounting grooves (42) arranged in an annular manner; The bottom end of the rubber cylinder lower support (16) is movably connected to a slip upper connecting rod (15) adapted to the slip lower connecting rod (13) via a plurality of second mounting grooves (47), and a toothed slip (14) is connected between the slip lower connecting rod (13) and the slip upper connecting rod (15) via a pin shaft.

4. A novel casing annulus packer according to claim 3, characterized in that: The directions of the engaging teeth (46) on two adjacent toothed slips (14) are opposite.

5. A novel casing annulus packer according to claim 2 or 3, characterized in that: The bottom end of the slip support (12) is provided with a straightening mechanism capable of straightening the casing via a lower joint (1).

6. A novel casing annulus packer according to claim 5, characterized in that: The righting mechanism comprises a righting support (2) threadedly connected to the bottom end of the lower joint (1); a righting slip ring (10) is provided between the righting support (2) and the slip support (12) via the lower joint (1); and the righting slip ring (10) and the slip support (12) are abutted against each other via a wave spring (11).

7. A novel casing annulus packer according to claim 6, characterized in that: The righting mechanism further comprises a righting assembly arranged between the righting support (2) and the righting slip ring (10); The righting assembly comprises a righting lower connecting rod (4) movably connected to the top of the righting support (2) via a third mounting groove (34); the bottom of the righting sliding ring (10) is connected to a righting upper connecting rod (9) corresponding to the righting lower connecting rod (4) via a pin; and a righting sliding block (8) is movably connected between the righting upper connecting rod (9) and the righting lower connecting rod (4) via a pin.

8. A novel casing annulus packer according to claim 7, characterized in that: The two ends of the straightening slider (8) are provided with roller mounting grooves (36), and rollers (7) are mounted through the roller mounting grooves (36) in cooperation with pins. A straightening middle connecting rod (6) connected to the straightening support (2) is provided between the two rollers (7) on the straightening slider (8) through a pin.

9. The novel casing annulus packer according to claim 1 is characterized in that: The casing annulus packer also includes a locking ring (28) with an annular opening, the inner wall of the locking ring (28) being provided with fine teeth (73) cooperating with the first ratchet teeth (69) on the outer wall of the upper piston (26), and the outer wall being provided with coarse teeth (74) cooperating with the second ratchet teeth (72) on the outer tube (27) of the locking ring.

10. A novel casing annulus packer according to claim 9, characterized in that: The outer wall of the bottom end of the lock ring outer cylinder (27) is threadedly connected to the upper piston outer cylinder (25).

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