Large-diameter washable bridge plug for non-metal pipe

Abstract

The application discloses a large-diameter washable bridge plug suitable for non-metal pipes, which comprises a tubular upper central pipe, a lower joint sleeved on the outer side of one end of the upper central pipe, a pipe sleeve sleeved on the outer side of the end of the lower joint connected with the upper central pipe, a rubber sleeve seat sleeved on the outer side of the pipe sleeve, an upper slip and accessories, a rubber sleeve, a lower slip and accessories installed on the outer side of the rubber sleeve seat from the end far from the lower joint, a soluble joint sleeved on the outer sides of the rubber sleeve seat and the pipe sleeve, an upper joint sleeved on the other end of the upper central pipe, an upper piston sleeved on the outer side of the upper central pipe next to the upper joint, and a reverse well washing mechanism arranged between the upper piston and the upper central pipe. The bridge plug can replace the conventional Y341 water injection packer matched with the existing non-metal oil pipe, and solves the problems of oil pipe thread breakage, even oil pipe breakage and downhole accidents caused by the matching use of the non-metal oil pipe and the water injection packer.

Description

Technical Field

[0001] This invention belongs to the field of oilfield water injection technology, specifically relating to a washable well bridge plug suitable for large-diameter non-metallic pipes. Background Technology

[0002] Non-metallic tubing in wells possesses strong corrosion resistance, effectively mitigating tubing corrosion. Furthermore, its smooth inner wall reduces scale buildup, lowers the resistance rate during testing and mixing, and effectively extends the service life of the injection string. However, non-metallic tubing is made of fiber and polymer materials, exhibiting characteristics such as high flexibility, high elongation, low tensile strength, and poor resistance to external extrusion compared to ordinary steel tubing. Therefore, the release force of the matching water injection packer should not be excessive. Currently, the Y341 water injection packer is commonly used with non-metallic tubing. Because the release force of the packer, combined with the weight of the non-metallic tubing itself, exceeds the tensile strength of the non-metallic tubing threads, difficulties arise in releasing the packer. Forcibly pulling up the non-metallic tubing can easily cause the threads to dislodge or even break, leading to downhole accidents. Summary of the Invention

[0003] The purpose of this invention is to provide a washable well plug suitable for large-diameter non-metallic tubing. This plug solves the problems of difficulty in unsealing conventional packers and easy breakage of non-metallic tubing threads during unsealing in non-metallic tubing applications.

[0004] The technical solution adopted in this invention is:

[0005] Suitable for large-diameter washable well bridge plugs for non-metallic tubing, including a tubular upper center tube, a lower connector sleeved on the outer side of one end of the upper center tube, an insert sleeve sleeved on the outer side of the end of the lower connector connected to the upper center tube, a rubber sleeve seat sleeved on the outer side of the insert sleeve, a fusible connector sleeved on the outer side of the rubber sleeve seat and the insert sleeve, and an upper slip and accessories, a rubber sleeve, and a lower slip and accessories are sequentially installed on the outer side of the rubber sleeve seat, starting from the end furthest from the lower connector; an upper connector sleeved on the other end of the upper center tube, an upper piston sleeved on the outer side of the upper center tube and adjacent to the upper connector, and a backwashing mechanism is provided between the upper center tube and the upper piston.

[0006] The invention is further characterized by:

[0007] The lower connector is connected and secured to the upper central tube via an internal thread, and the lower connector is connected and secured to the insertion tube via an external thread.

[0008] A bushing is provided between the upper slip and the upper piston, and a retaining ring is provided between the lower slip and the fusible joint.

[0009] The soluble connector secures the rubber sleeve and the insertion tube together via internal threads.

[0010] One end of the upper piston is fixed to the outside of the rubber sleeve seat by a pin.

[0011] An upper outer sleeve is fitted onto the outer side of the end of the upper connector that connects to the upper central tube, and the upper connector and the upper outer sleeve are fastened together by a pin.

[0012] The reverse well washing mechanism includes an upper well washing sleeve, a well washing piston is sleeved between the upper well washing sleeve and the upper central tube, and a well washing spring is installed between the upper well washing sleeve and the well washing piston.

[0013] The outer circumference of the insertion tube is evenly provided with several sealing ring grooves. The outer circumference of the lower end of the upper connector, the outer circumference and inner hole of the upper piston, the contact point between the upper central tube and the upper washing sleeve, and the outer circumference and inner hole of the upper and lower ends of the washing piston are all provided with sealing ring grooves. Sealing rings are installed in the sealing ring grooves.

[0014] The beneficial effects of this invention are:

[0015] This invention designs a large-diameter washable well plug suitable for non-metallic tubing. This plug can replace the conventional Y341 water injection packer that is used with existing non-metallic tubing, solving the problem of tubing thread breakage or even tubing breakage causing downhole accidents when non-metallic tubing is used with water injection packers. It further expands the application range of non-metallic tubing in water injection wells and reduces the tubing string replacement cost throughout the entire life cycle of water injection wells.

[0016] The large-diameter washable well plug of this invention has two main features: First, it achieves a sealing connection between the sealing ring assembly of the insertion tube and the inner wall of the rubber sleeve seat. Upon unsealing, the soluble joint dissolves in water, allowing for easy well lifting by raising the tubing string. Second, the well-washing channel formed by the upper central tube, upper washing sleeve, washing spring, washing piston, and the inner wall of the insertion tube enables the backwashing function of the drillable bridge plug. This invention fills a market gap for such products, meets the needs of precise water injection, and features simple design, easy operation, and good sealing performance. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of the large-diameter washable well bridge plug of the present invention.

[0018] In the diagram, 1. Upper connector, 2. Upper outer sleeve, 3. Upper piston, 4. Upper well-washing sleeve, 5. Lower slip, 6. Upper central tube, 7. Rubber sleeve, 8. Well-washing spring, 9. Well-washing piston, 10. Liner ring, 11. Rubber sleeve seat, 12. Insert pipe, 13. Retaining ring, 14. Soluble connector, 15. Lower connector, 16. Upper slip. Detailed Implementation

[0019] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0020] Example 1

[0021] like Figure 1As shown, the washable well plug of the present invention includes a tubular upper central tube 6. A lower connector 15 is sleeved on the outer side of one end of the upper central tube 6. An insert tube 12 is sleeved on the outer side of the end of the lower connector 15 that connects to the upper central tube 6. The lower connector 15, the upper central tube 6, and the insert tube 12 are all threadedly connected. A rubber sleeve seat 11 is sleeved on the outer side of the insert tube 12. Starting from the end away from the lower connector 15, a bushing 10, an upper slip 16 and accessories, a rubber sleeve 7, a lower slip 5 and accessories, and a retaining ring 13 are installed sequentially on the outer side of the rubber sleeve seat 11. A fusible connector 14 is sleeved on the outside of the rubber sleeve seat 11 and the insert tube 12. The fusible connector 14 connects and secures the rubber sleeve seat 11 and the insert tube 12 through internal threads. An upper connector 1 is sleeved on the other end of the upper central tube 6. An upper piston 3 is sleeved on the outside of the upper central tube 6 close to the upper connector 1. One end of the upper piston 3 is fixed to the outer side of the rubber sleeve seat 11 by a pin. A backwashing mechanism is provided between the insert tube 12 and the upper central tube 6.

[0022] Example 2

[0023] like Figure 1 As shown, the washable well plug of the present invention includes a tubular upper central tube 6. A lower connector 15 is sleeved on the outer side of one end of the upper central tube 6. An insert tube 12 is sleeved on the outer side of the end of the lower connector 15 that connects to the upper central tube 6. The lower connector 15, the upper central tube 6, and the insert tube 12 are all threadedly connected. A rubber sleeve seat 11 is sleeved on the outer side of the insert tube 12. Starting from the end away from the lower connector 15, a bushing 10, an upper slip 16 and accessories, a rubber sleeve 7, a lower slip 5 and accessories, and a retaining ring 13 are installed sequentially on the outer side of the rubber sleeve seat 11. A fusible connector 14 is sleeved on the outside of the rubber sleeve seat 11 and the insert tube 12. The fusible connector 14 connects and secures the rubber sleeve seat 11 and the insert tube 12 through internal threads. An upper connector 1 is sleeved on the other end of the upper central tube 6. An upper piston 3 is sleeved on the outside of the upper central tube 6 close to the upper connector 1. One end of the upper piston 3 is fixed to the outer side of the rubber sleeve seat 11 by a pin. A backwashing mechanism is provided between the insert tube 12 and the upper central tube 6. The backwashing mechanism includes an upper washing sleeve 4, a washing piston 9 is sleeved between the upper washing sleeve 4 and the upper central tube 6, and a washing spring 8 is provided between the upper washing sleeve 4 and the washing piston 9. An upper outer sleeve 2 is sleeved on the outer side of the end of the upper connector 1 that is connected to the upper central tube 6, and the upper outer sleeve 2 is locked to the upper connector 1 by a pin.

[0024] Example 3

[0025] like Figure 1As shown, the washable well plug of the present invention includes a tubular upper central tube 6. A lower connector 15 is sleeved on the outer side of one end of the upper central tube 6. An insert tube 12 is sleeved on the outer side of the end of the lower connector 15 that connects to the upper central tube 6. The lower connector 15, the upper central tube 6, and the insert tube 12 are all threadedly connected. A rubber sleeve seat 11 is sleeved on the outer side of the insert tube 12. Starting from the end away from the lower connector 15, a bushing 10, an upper slip 16 and accessories, a rubber sleeve 7, a lower slip 5 and accessories, and a retaining ring 13 are installed sequentially on the outer side of the rubber sleeve seat 11. A fusible connector 14 is sleeved on the outside of the rubber sleeve seat 11 and the insert tube 12. The fusible connector 14 connects and secures the rubber sleeve seat 11 and the insert tube 12 through internal threads. An upper connector 1 is sleeved on the other end of the upper central tube 6. An upper piston 3 is sleeved on the outside of the upper central tube 6 close to the upper connector 1. One end of the upper piston 3 is fixed to the outer side of the rubber sleeve seat 11 by a pin. A backwashing mechanism is provided between the insert tube 12 and the upper central tube 6. The backwashing mechanism includes an upper washing sleeve 4, a washing piston 9 is sleeved between the upper washing sleeve 4 and the upper central tube 6, and a washing spring 8 is provided between the upper washing sleeve 4 and the washing piston 9. An upper outer sleeve 2 is sleeved on the outer side of the end of the upper connector 1 that is connected to the upper central tube 6, and the upper outer sleeve 2 is locked to the upper connector 1 by a pin.

[0026] The outer circumference of the insertion tube 12 is evenly provided with several sealing ring grooves, and a sealing ring is installed in each of the sealing ring grooves.

[0027] Example 4

[0028] This invention provides a washable well bridge plug suitable for large-diameter non-metallic tubing, with the structure as follows: Figure 1 As shown, it includes a tubular upper central tube 6, with a lower connector 15 sleeved on the outer side of one end of the upper central tube 6, and an insertion tube 12 sleeved on the outer side of the end of the lower connector 15 that connects to the upper central tube 6. The lower connector 15, the upper central tube 6, and the insertion tube 12 are all threaded connections. A rubber sleeve seat 11 is sleeved on the outer side of the insertion tube 12. On the outer side of the rubber sleeve seat 11, starting from the end away from the lower connector 15, a bushing 10, an upper clamp 16 and accessories, a rubber sleeve 7, a lower clamp 5 and accessories, and a retaining ring 13 are installed in sequence. A fusible connector 14 is sleeved on the outside of the rubber sleeve seat 11 and the insertion tube 12. The fusible connector 14 connects and secures the rubber sleeve seat 11 and the insertion tube 12 through internal threads. The other end of the upper central tube 6 is fitted with an upper connector 1. The upper piston 3 is fitted onto the outside of the upper central tube 6, close to the upper connector 1. One end of the upper piston 3 is fixed to the outside of the rubber sleeve seat 11 by a pin. A backwashing mechanism is provided between the insertion tube 12 and the upper central tube 6. The backwashing mechanism includes an upper washing sleeve 4. A washing piston 9 is fitted between the upper washing sleeve 4 and the upper central tube 6. A washing spring 8 is provided between the upper washing sleeve 4 and the washing piston 9. An upper outer sleeve 2 is fitted onto the outside of the end of the upper connector 1 that is connected to the upper central tube 6. The upper outer sleeve 2 and the upper connector 1 are locked together by a pin.

[0029] The outer circumference of the insertion tube 12 is evenly provided with several sealing ring grooves. The outer circumference of the lower end of the upper connector 1, the outer circumference and inner hole of the upper piston 3, the contact point between the upper central tube 6 and the upper washing sleeve 4, and the outer circumference and inner hole of the upper and lower ends of the washing piston 9 are all provided with sealing ring grooves, and sealing rings are installed in the sealing ring grooves.

[0030] The specific connection steps of the large-diameter washable well bridge plug of this invention are as follows:

[0031] Step 1: Connect the lower connector 15 to the insertion tube 12 by thread, and install the matching sealing ring of the insertion tube 12 in the sealing ring groove;

[0032] Step 2: Place the rubber sleeve 11 onto the insertion tube 12 and adjust it to a suitable position;

[0033] Step 3: On the outside of the rubber sleeve seat 11, starting from the end furthest from the lower connector 15, install the bushing 10, upper clamp 16 and accessories, rubber sleeve 7, lower clamp 5 and accessories, and retaining ring 13 in sequence. Then, adjust the left and right positions of the retaining ring 13 by thread to firmly connect the above parts.

[0034] Step 4: First, securely connect the soluble connector 14 to the rubber sleeve seat 11 with threads, and then securely connect it to the insertion tube 12 with threads.

[0035] Step 5: First, install the matching sealing rings of the upper central tube 6 and the well washing piston 9 into their respective sealing ring grooves, and then connect the upper central tube 6 with the upper well washing sleeve 4, the well washing spring 8, and the well washing piston 9.

[0036] Step 6: Securely connect the upper central tube 6 (connected in Step 5) and the lower connector 15 (connected in Step 4) using threads.

[0037] Step 7: Install the sealing ring of the upper piston 3 into the sealing ring groove, then put the upper piston 3 into the upper central tube 6, and fix the upper piston 3 to the rubber sleeve seat 11 with a pin;

[0038] Step 8: Securely connect the upper connector 1 to the upper center tube 6 using threads, and install the sealing ring of the upper connector 1 into the sealing ring groove;

[0039] Step 9: Securely connect the upper jacket 2 to the upper connector 1 using threads and lock it in place with a pin.

[0040] The working process of this invention, suitable for large-diameter washable well plugs for non-metallic pipes, is as follows:

[0041] In use, the bridge plug is connected to the injection well tubing. The lower part of the bridge plug is usually connected to the water distributor and the tailpipe with a plug. The tubing with the water injection switch is lowered into the target section of the injection well by the workover machine. Then, the pump truck connected to the ground pressurizes the tubing, pushing the upper piston 3 to cut the pin connected to the rubber sleeve seat 11. Then the upper piston 3 moves downward, pushing the liner ring 10, the upper slip 16 and accessories, the rubber sleeve 7 and the lower slip 5 to squeeze each other, so that the rubber sleeve 7, the lower slip 5 and the upper slip 16 are spread open and engaged with the inner wall of the casing, so as to achieve the purpose of sealing the injection section.

[0042] When well washing is required, the pressure inside the tubing is first reduced to atmospheric pressure. Then, the pump truck pressurizes the annulus of the tubing string from the ground. The pump truck pressure enters through the water washing hole of the upper piston 3. The pressure acts on the outer surface of the well washing piston 9, pushing the well washing piston 9 to compress the well washing spring 8 and move it upward. This opens the well washing channel formed by the well washing piston 9, the insertion pipe 12, and the upper central pipe 6, thus realizing the reverse washing of this type of water injection tubing string.

[0043] When it is necessary to pull out the water injection string, under the action of the highly salinized water in the formation, the soluble connector 14 completely dissolves, and the main component of the bridge plug, namely the rubber sleeve seat 11 and the outside of the rubber sleeve seat 11, is fixedly disconnected from the threaded connection of the insertion tube 12. The string is then pulled up, which in turn pulls the upper connector 1, upper central tube 6, lower connector 15, insertion tube 12, well washing piston 9, well washing spring 8, upper well washing sleeve 4, upper piston 3, upper outer sleeve 2 and other components out of the wellbore along with the string.

[0044] The large-diameter washable well bridge plug of this invention can effectively solve the problem that conventional Y341 water injection packers used with non-metallic tubing are prone to breakage and downhole accidents due to the combined effect of the unsealing force and the weight of the tubing string exceeding the tensile strength of the non-metallic tubing threads. This further expands the applicability of water injection in non-metallic tubing.

Claims

1. A washable well plug suitable for large diameter non-metallic pipes, characterized in that: The system includes a tubular upper central tube (6), with a lower connector (15) sleeved on the outer side of one end of the upper central tube (6), and an insert tube (12) sleeved on the outer side of the end of the lower connector (15) connected to the upper central tube (6). A rubber sleeve seat (11) is sleeved on the outer side of the insert tube (12), and a soluble connector (14) is sleeved on the outer side of the rubber sleeve seat (11), starting from the end furthest from the lower connector (15). An upper slip (16) and accessories, a rubber sleeve (7), and a lower slip (5) and accessories are installed sequentially on the outer side of the rubber sleeve seat (11). An upper connector (1) is sleeved on the other end of the upper central tube (6), and an upper piston (3) is sleeved on the outer side of the upper central tube (6) close to the upper connector (1). A backwashing mechanism is provided between the upper central tube (6) and the upper piston (3). The lower connector (15) is connected and fastened to the upper central tube (6) by an internal thread, and the lower connector (15) is connected and fastened to the insertion tube (12) by an external thread; One end of the upper piston (3) is fixed to the outside of the rubber sleeve seat (11) by a pin; The reverse well washing mechanism includes an upper well washing sleeve (4), a well washing piston (9) is sleeved between the upper well washing sleeve (4) and the upper central tube (6), and a well washing spring (8) is provided between the upper well washing sleeve (4) and the well washing piston (9).

2. The washable well plug suitable for large diameter non-metallic pipes according to claim 1, characterized in that, A bushing (10) is provided between the upper slip (16) and the upper piston (3), and a retaining ring (13) is provided between the lower slip (5) and the soluble connector (14).

3. The washable well plug suitable for large diameter non-metallic pipes according to claim 1, characterized in that, The soluble connector (14) connects and secures the rubber sleeve seat (11) and the insertion tube (12) through internal threads.

4. The washable well plug suitable for large diameter non-metallic pipes according to claim 1, characterized in that, The upper connector (1) is connected to the upper central tube (6) with an upper outer sleeve (2) on the outer side. The upper connector (1) and the upper outer sleeve (2) are fastened together by pins.

5. The washable well plug suitable for large diameter non-metallic pipes according to claim 1, characterized in that, The outer circle of the insertion tube (12) is uniformly provided with several sealing ring grooves. The outer circle of the lower end of the upper connector (1), the outer circle and inner hole of the upper piston (3), the contact point between the upper central tube (6) and the upper washing sleeve (4), the outer circle of the upper and lower ends of the washing piston (9) and the inner hole of the upper end are all provided with sealing ring grooves. Sealing rings are installed in the sealing ring grooves.

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