Multifunctional recovery rubber sleeve type packer for multi-layer fracturing process

Abstract

The invention relates to the technical field of oil field immovable string multi-layer fracturing anti-blocking measures, in particular to a multifunctional recovery rubber sleeve type packer for a multi-layer fracturing process. The packer comprises an upper connector, the outer side of the upper connector is connected with an upper rubber sleeve seat, the lower side of the upper connector is provided with a center pipe, a plurality of shear pin assemblies are connected between the center pipe and the upper rubber sleeve seat, a first annulus is arranged between the upper rubber sleeve seat and the center pipe, and the outer side of the center pipe is sequentially connected with a rubber sleeve, a connecting sleeve and a lower connector. An upper rubber sleeve seat and a lower rubber sleeve seat are installed at the two ends of the rubber sleeve respectively, a second annulus is arranged between the lower rubber sleeve seat and the connecting sleeve, a deblocking assisting spring is installed in the second annulus, and a lower connector is arranged at the bottom end of the lower rubber sleeve seat. According to the packer provided by the invention, not only can automatic unsealing be realized through the unsealing assisting spring, but also starting and stopping of radial recovery of the rubber sleeve can be completed by lifting the upper joint besides the conventional unsealing depending on the self-recovery force of the rubber sleeve, so that forced unsealing is effectively realized, and smooth recovery of the packer is further ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of anti-sticking measures for multi-layer fracturing of oil wells without pulling out the pipe string, and particularly relates to a multi-functional recovery rubber barrel type packer for multi-layer fracturing technology. Background Art

[0002] At present, compression rubber barrel packers are widely used in oil well cementing, oil production and stimulation operations. The setting forms of this type of packer mainly include mechanical setting and hydraulic setting. In actual applications, regardless of which setting form, the compression rubber barrel packer achieves sealing by squeezing the rubber barrel to deform. Generally speaking, the compression rubber barrel packer completes the lifting and lowering of the work string or the pressure build-up in the pipe to achieve sealing through the compression rubber barrel assembly. The compression rubber barrel assembly is relatively short in length, has good sealing effect in the casing, and can withstand high pressure.

[0003] The hydraulic packer mainly installs the rubber barrel on the central pipe. The material of the rubber barrel is swelling rubber when contacting liquid. When the swelling rubber material contacts the underground oil, gas and water, the volume of the rubber expands, so as to achieve the purpose of sealing the annular space. The swelling rubber when contacting liquid can adapt to the changes of different well diameters.

[0004] With the development of oil production technology in oil wells, the distance between perforations is getting closer and closer. When carrying out layered isolation, the previous general packers are ineffective, and long rubber barrels must be used to isolate the oil layers. In the operation process of oil wells or injection wells, several layers are divided in one well. The increase in the number of fracturing layers leads to an increase in the number of packers, which easily causes the problem of difficult movement of the pipe string. In addition, the existing pipe string is prone to the problem of not opening when lifted, resulting in major repairs, which increases the cost of a single well and delays the construction. Therefore, in view of the above deficiencies, a multi-functional recovery rubber barrel type packer for multi-layer fracturing technology is proposed. Summary of the Invention

[0005] (I) Technical Problems to be Solved The present invention provides a multi-functional recovery rubber barrel type packer for multi-layer fracturing technology, which avoids the problems in the existing method of using packers to isolate oil layers. Due to adverse working conditions such as long single-layer construction time, high temperature during post-fracture shut-in, long soaking period, and the rubber barrel being in a high-pressure expansion state for a long time, the rubber barrel is prone to fatigue failure, or the recovery speed of the rubber barrel slows down and the recovery force decreases, resulting in the pipe string not opening when moved, and further causing problems such as difficult recovery or major repairs.

[0006] (II) Technical Solutions To solve the above problems, the present invention provides a multi-functional recovery rubber barrel type packer for multi-layer fracturing technology, including: Upper joint, the outer side of the upper joint is connected with an upper rubber cylinder seat through threads, the lower side of the upper joint is a central tube, a plurality of shear pin assemblies are connected between the central tube and the upper rubber cylinder seat, a first annulus is arranged between the central tube and the upper rubber cylinder seat, the outer side of the central tube is sequentially connected with a rubber cylinder, a connecting sleeve and a lower joint, both ends of the rubber cylinder are respectively provided with an upper rubber cylinder seat and a lower rubber cylinder seat, a second annulus is arranged between the lower rubber cylinder seat and the connecting sleeve, a booster unsealing spring is installed in the second annulus, and the bottom end of the lower rubber cylinder seat is a lower joint; After the shear pin assembly breaks, the upper joint can drive the upper rubber cylinder seat to move upward, the first annulus limits the moving distance of the upper rubber cylinder seat, the upper rubber cylinder seat synchronously drives the rubber cylinder and the lower rubber cylinder seat to move upward, the rubber cylinder can expand and contract, the booster unsealing spring can stretch, the lower rubber cylinder seat compresses the booster unsealing spring by moving upward, and the second annulus limits the stretching distance of the booster unsealing spring.

[0007] Preferably, the shear pin assembly includes soluble shear pins and springs, a plurality of soluble shear pins are connected between the central tube and the upper rubber cylinder seat, springs are sleeved on the outer sides of the lower ends of the soluble shear pins, and the lower ends of the springs are the central tube.

[0008] Preferably, the soluble shear pins can dissolve, the soluble shear pins complete the fracture of the shear pin assembly through dissolution, the soluble shear pins stretch the springs through dissolution, and the springs can maintain the connection distance between the central tube and the upper rubber cylinder seat.

[0009] Preferably, after the booster unsealing spring is compressed to the limit, both ends of the booster unsealing spring are respectively connected with the lower rubber cylinder seat and the connecting sleeve, and the rubber cylinder starts radial recovery.

[0010] Preferably, the central tube is provided with a step, the first annulus is between the step and the upper rubber cylinder seat, the upper rubber cylinder seat is connected with the step by moving upward, and the rubber cylinder stops radial recovery.

[0011] Preferably, the inner side of the rubber cylinder is connected with the central tube through threads, the lower end of the rubber cylinder is a connecting sleeve, there is a gap between the rubber cylinder and the connecting sleeve, the inner side of the connecting sleeve is connected with the central tube through threads, the outer side of the connecting sleeve is connected with the lower rubber cylinder seat, and the inner side of the lower joint is connected with the central tube through threads.

[0012] Preferably, the upper joint and the upper rubber cylinder seat are fixed through anti-rotation pins.

[0013] Preferably, the lower rubber cylinder seat and the connecting sleeve are sealed through a sealing ring.

[0014] (III)Advantages The multi-functional recovery rubber barrel type packer for multi-layer fracturing process provided by the present invention can not only be released by relying on the self-recovery force of the rubber barrel conventionally, but also can be automatically released through the auxiliary release spring, making the release more labor-saving and effectively solving the problem of difficult moving pipe string. At the same time, the start and stop of the radial recovery of the rubber barrel are completed by lifting the upper joint, effectively realizing forced release. On the basis of self-help release, the release operation of the packer can be realized more thoroughly, further ensuring the smooth recovery of the packer. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic structural diagram of the multi-functional recovery rubber barrel type packer for multi-layer fracturing process in the embodiment of the present invention; Figure 2 In the embodiment of the present invention Figure 1 The cross-sectional schematic diagram at A-A in; Figure 3 It is a schematic structural diagram of the shear pin assembly in the embodiment of the present invention.

[0016] Wherein: 1 - upper joint; 2 - anti-rotation pin; 3 - upper rubber barrel seat; 4 - soluble shear pin; 5 - spring; 6 - central tube; 7 - rubber barrel; 8 - lower rubber barrel seat; 9 - connecting sleeve; 10 - auxiliary release spring; 11 - sealing ring; 12 - lower joint. EMBODIMENTS

[0017] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0018] In the description of the present invention, it is necessary to understand that the orientation or positional relationship indicated by "upper", "lower", "inner", "outer", "top", "bottom", etc. is all based on the orientation or positional relationship shown in the drawings. The purpose is only to facilitate the description of the present invention and simplify the description, rather than indicating or implying that the indicated components must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present invention.

[0019] Figure 1 It is a schematic structural diagram of the multi-functional recovery rubber barrel type packer for multi-layer fracturing process in the embodiment of the present invention, Figure 2 In the embodiment of the present invention Figure 1 The cross-sectional schematic diagram at A-A in, as Figures 1 to 2 shown, the present invention provides a multi-functional recovery rubber barrel type packer for multi-layer fracturing process, including: Upper joint 1, the outer side of the upper joint 1 is connected to the rubber cylinder seat 3 by thread. The lower side of the upper joint 1 is the central tube 6. A plurality of shear pin assemblies are connected between the central tube 6 and the rubber cylinder seat 3. There is a first annulus between the rubber cylinder seat 3 and the central tube 6. The outer side of the central tube 6 is sequentially connected to the rubber cylinder 7, the connecting sleeve 9 and the lower joint 12. Both ends of the rubber cylinder 7 are respectively installed with the upper rubber cylinder seat 3 and the lower rubber cylinder seat 8. There is a second annulus between the lower rubber cylinder seat 8 and the connecting sleeve 9. The second annulus is installed with an auxiliary unsealing spring 10. The bottom end of the lower rubber cylinder seat 8 is the lower joint 12.

[0020] In practical applications, after the shear pin assembly breaks, the upper joint 1 can drive the upper rubber cylinder seat 3 to move upward. The first annulus limits the moving distance of the upper rubber cylinder seat 3. The upper rubber cylinder seat 3 synchronously drives the rubber cylinder 7 and the lower rubber cylinder seat 8 to move upward. The rubber cylinder 7 can expand and contract. The auxiliary unsealing spring 10 can expand and contract. The lower rubber cylinder seat 8 compresses the auxiliary unsealing spring 10 by moving upward. The second annulus limits the expansion and contraction distance of the auxiliary unsealing spring 10.

[0021] Figure 3 It is a schematic structural diagram of the shear pin assembly in the embodiment of the present invention. As Figure 3 shown, in this packer, the shear pin assembly includes soluble shear pins 4 and springs 5. A plurality of soluble shear pins 4 are connected between the central tube 6 and the upper rubber cylinder seat 3. Springs 5 are sleeved on the outer sides of the lower ends of the soluble shear pins 4. The lower ends of the springs 5 are the central tube 6. In practical applications, the soluble shear pins 4 can dissolve. The soluble shear pins 4 complete the fracture of the shear pin assembly by dissolving. The soluble shear pins 4 stretch the springs 5 by dissolving. The springs 5 can maintain the connection distance between the central tube 6 and the upper rubber cylinder seat 3.

[0022] In this packer, after the auxiliary unsealing spring 10 is compressed to the limit, both ends of the auxiliary unsealing spring 10 are respectively connected to the lower rubber cylinder seat 8 and the connecting sleeve 9. The rubber cylinder 7 starts radial recovery. In addition, the central tube 6 is provided with a step. The first annulus is between the step and the upper rubber cylinder seat 3. The upper rubber cylinder seat 3 is connected to the step by moving upward. The rubber cylinder 7 stops radial recovery.

[0023] In practical applications, the inner side of the rubber cylinder 7 is connected to the central tube 6 by thread. The lower end of the rubber cylinder 7 is the connecting sleeve 9. There is a gap between the rubber cylinder 7 and the connecting sleeve 9. The inner side of the connecting sleeve 9 is connected to the central tube 6 by thread. The outer side of the connecting sleeve 9 is connected to the lower rubber cylinder seat 8. The inner side of the lower joint 12 is connected to the central tube 6 by thread.

[0024] It should be noted that the upper joint 1 and the upper rubber cylinder seat 3 are fixed by anti-rotation pins 2. The lower rubber cylinder seat 8 and the connecting sleeve 9 are sealed by a sealing ring 11.

[0025] In practical applications, unsealing is achieved through the self-recovery force of the rubber cylinder 7. The packer can also achieve self-service unsealing. At the same time, under the action of hydraulic pressure, the auxiliary unsealing spring 10 is extended and retracted to achieve sealing and self-service unsealing. In addition, the packer can also achieve forced unsealing. After the soluble shear pin 4 is dissolved, the packer pulls up the upper joint 1, and the upper joint 1 drives the upper rubber cylinder seat 3 to move upward. The upper rubber cylinder seat 3 simultaneously drives the sealed rubber cylinder 7 and the lower rubber cylinder seat 8. The second annulus is shortened by the lower rubber cylinder seat 8. The lower rubber cylinder seat 8 compresses the auxiliary unsealing spring 10 by moving upward. When the auxiliary unsealing spring 10 is compressed to the limit state, the auxiliary unsealing spring 10 is respectively connected to the connecting sleeve 9 and the lower rubber cylinder seat 8, stretching the rubber cylinder 7 for radial recovery, and continuing to lift the upper joint 1. The distance of the first annulus is reduced, and the step of the central pipe 6 contacts the upper rubber cylinder seat 3, and the radial recovery of the rubber cylinder 7 stops.

[0026] The multifunctional recovery rubber cartridge type packer for multi-layer fracturing process provided by the present invention can realize automatic unsealing through the auxiliary unsealing spring in addition to the conventional unsealing by relying on the self-recovery force of the rubber cartridge, which is more labor-saving and effectively solves the difficulty of moving the pipe string. At the same time, the radial recovery of the rubber cartridge is started and stopped by pulling the upper joint, and forced unsealing is effectively realized. On the basis of self-service unsealing, the unsealing operation of the packer can be more thoroughly realized, and the smooth recovery of the packer is further guaranteed. The working principle of this multifunctional recovery rubber cartridge type packer for multi-layer fracturing process is described in detail below: In this embodiment, the upper joint 1 is connected to the upper rubber cylinder seat 3 through the anti-rotation pin 2, the lower side of the upper joint 1 is the center tube 6, and four soluble shear pins 4 are connected between the center tube 6 and the upper rubber cylinder seat 3. The outer side of the lower end of the soluble shear pin 4 is sleeved with a spring 5, and the lower end of the spring 5 is the center tube 6. The center tube 6 is provided with a step, and a first annulus is provided between the upper rubber cylinder seat 3 and the center tube 6. The lower end of the upper rubber cylinder seat 3 is installed with a rubber cylinder 7, and the lower end of the rubber cylinder 7 is installed on the lower rubber cylinder seat 8. The inner side of the rubber cylinder 7 is through A central tube 6 is threadedly connected, and the lower end of the rubber cylinder 7 is a connecting sleeve 9. A gap is provided between the rubber cylinder 7 and the connecting sleeve 9. The inner side of the connecting sleeve 9 is connected to the central tube 6 by a thread. The outer side of the connecting sleeve 9 is connected to the lower rubber cylinder seat 8. The inner side of the lower joint 12 is threadedly connected to the central tube 6. A second annulus is provided between the lower rubber cylinder seat 8 and the connecting sleeve 9. An auxiliary unsealing spring 10 is installed in the second annulus. The lower rubber cylinder seat 8 and the connecting sleeve 9 are sealed by a sealing ring 11. The bottom end of the lower rubber cylinder seat 8 is a lower joint 12.

[0027] In practical applications, the packer achieves the function of isolating the fractured layer and the non-fractured layer by expanding the rubber tube 7, and the packer is released by the self-recovery force of the rubber tube 7; Meanwhile, when the liquid flows into the second annulus, under the hydraulic action, the auxiliary unsealing spring 10 can contract, and setting can be achieved through the auxiliary unsealing spring 10. When the auxiliary unsealing spring 10 rebounds, self-unsealing is achieved through the auxiliary unsealing spring 10, effectively solving the problem of difficult moving pipe string. Compared with the traditional unsealing structure, through the setting of the auxiliary unsealing spring, automatic unsealing can be achieved, and the unsealing is more labor-saving; In addition, the soluble shear pin 4 completes the fracture of the shear pin assembly through dissolution. After the soluble shear pin 4 dissolves, the soluble shear pin 4 stretches the spring 5 through dissolution. The spring 5 can maintain the connection distance between the central tube 6 and the upper rubber cylinder seat 3. By lifting the upper joint 1, the upper joint 1 drives the upper rubber cylinder seat 3 to move upward. The upper rubber cylinder seat 3 synchronously drives the set rubber cylinder 7. By moving the rubber cylinder 7 upward, the lower rubber cylinder seat 8 can also move upward. Due to the movement of the lower rubber cylinder seat 8, the distance of the second annulus becomes shorter. The lower rubber cylinder seat 8 compresses the auxiliary unsealing spring 10 by moving upward. When the auxiliary unsealing spring 10 is compressed to the limit state, the connecting sleeve 9 connects the auxiliary unsealing spring 10, and the lower end of the auxiliary unsealing spring 10 is connected to the lower rubber cylinder seat 8, forcibly stretching the rubber cylinder 7 to radially recover. Continuing to lift the upper joint 1, the distance of the first annulus decreases until the step of the central tube 6 contacts the upper rubber cylinder seat 3, and the radial recovery of the rubber cylinder 7 stops, further realizing forced unsealing. On the basis of automatic unsealing, not only can the unsealing operation of the packer be more thoroughly realized, but also the smooth recovery of the packer can be ensured.

[0028] The above embodiments are only used to illustrate the present invention, rather than limiting the present invention. Those of ordinary skill in the relevant technical fields can also make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, all equivalent technical solutions also belong to the scope of the present invention. The patent protection scope of the present invention shall be defined by the claims.

Claims

1. A multifunctional recovery rubber barrel type packer for multi-layer fracturing technology, characterized in that, Comprising: An upper joint (1), the outer side of the upper joint (1) is threadedly connected to an upper rubber cylinder seat (3), the lower side of the upper joint (1) is a central tube (6), a plurality of shear pin assemblies are connected between the central tube (6) and the upper rubber cylinder seat (3), a first annulus is provided between the central tube (6) and the upper rubber cylinder seat (3), the outer side of the central tube (6) is sequentially connected to a rubber cylinder (7), a connecting sleeve (9) and a lower joint (12), both ends of the rubber cylinder (7) are respectively installed with an upper rubber cylinder seat (3) and a lower rubber cylinder seat (8), a second annulus is provided between the lower rubber cylinder seat (8) and the connecting sleeve (9), a helping unsealing spring (10) is installed in the second annulus, and the bottom end of the lower rubber cylinder seat (8) is a lower joint (12); After the shear pin assembly breaks, the upper joint (1) can drive the upper rubber cylinder seat (3) to move upward, the first annulus limits the moving distance of the upper rubber cylinder seat (3), the upper rubber cylinder seat (3) synchronously drives the rubber cylinder (7) and the lower rubber cylinder seat (8) to move upward, the rubber cylinder (7) can expand and contract, the helping unsealing spring (10) can expand and contract, the lower rubber cylinder seat (8) compresses the helping unsealing spring (10) by moving upward, and the second annulus limits the expansion and contraction distance of the helping unsealing spring (10).

2. The multifunctional recovery rubber barrel type packer for multi-layer fracturing process according to claim 1, characterized in that, The shear pin assembly includes soluble shear pins (4) and springs (5), a plurality of soluble shear pins (4) are connected between the central tube (6) and the upper rubber cylinder seat (3), a spring (5) is sleeved on the outer side of the lower end of the soluble shear pin (4), and the lower end of the spring (5) is the central tube (6).

3. The multifunctional recovery rubber barrel type packer for multi-layer fracturing process according to claim 2, wherein, The soluble shear pins (4) can dissolve, the soluble shear pins (4) complete the breakage of the shear pin assembly through dissolution, the soluble shear pins (4) stretch the spring (5) through dissolution, and the spring (5) can maintain the connection distance between the central tube (6) and the upper rubber cylinder seat (3).

4. The multifunctional recovery rubber barrel type packer for multi-layer fracturing process according to claim 1, wherein, After the helping unsealing spring (10) is compressed to the limit, both ends of the helping unsealing spring (10) are respectively connected to the lower rubber cylinder seat (8) and the connecting sleeve (9), and the rubber cylinder (7) starts radial recovery.

5. The multifunctional recovery rubber barrel type packer for multi-layer fracturing process according to claim 1, characterized in that, The central tube (6) is provided with a step, the first annulus is between the step and the upper rubber cylinder seat (3), the upper rubber cylinder seat (3) is connected to the step by moving upward, and the rubber cylinder (7) stops radial recovery.

6. The multifunctional recovery rubber barrel type packer for multi-layer fracturing process according to claim 1, characterized in that, The inner side of the rubber cylinder (7) is threadedly connected to the central tube (6), the lower end of the rubber cylinder (7) is the connecting sleeve (9), there is a gap between the rubber cylinder (7) and the connecting sleeve (9), the inner side of the connecting sleeve (9) is threadedly connected to the central tube (6), the outer side of the connecting sleeve (9) is connected to the lower rubber cylinder seat (8), and the inner side of the lower joint (12) is threadedly connected to the central tube (6).

7. The multifunctional recovery rubber barrel type packer for multi-layer fracturing process according to claim 1, wherein, The upper joint (1) and the upper rubber cylinder seat (3) are fixed by anti-rotation pins (2).

8. The multifunctional recovery rubber barrel type packer for multi-layer fracturing process according to claim 6, characterized in that, The lower rubber cylinder seat (8) and the connecting sleeve (9) are sealed by a sealing ring (11).

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