Thermal recovery packer capable of achieving rapid setting

Abstract

The utility model discloses a thermal recovery packer capable of achieving rapid setting, and relates to the technical field of oil field downhole tools. A central pipe is arranged on the lower portion of the upper connector, the lower end of the central pipe is in threaded sealing connection with a lower connector, the outer circle of the lower connector is fixedly connected with a cylinder sleeve through a pin and a sealing ring, a piston is arranged between the cylinder sleeve and the central pipe, and the piston is in clearance fit with the cylinder sleeve and the central pipe through sealing rings. An upper baffle ring, a rubber sleeve and a lower baffle ring are sequentially sleeved on the central pipe below the step surface A of the upper joint, and the lower baffle ring is pressed on the top of the piston. The packer has the advantages that setting is achieved through pressure of injected steam instead of expansion of a thermosensitive medium, the setting process is fast, fast setting can be achieved without waiting for temperature rise of a shaft, the rubber sleeve keeps stable in sealing within a certain temperature range and is not affected by steam temperature change by arranging the limiting assembly, and the packer is simple in structure and convenient to operate. Meanwhile, the method has the characteristic of quick deblocking.

Description

Technical Field

[0001] This utility model relates to the field of oilfield downhole tools technology, and in particular to a rapid-setting thermal recovery packer. Background Technology

[0002] In the thermal extraction of heavy oil wells, thermal recovery packers are needed to seal the annular space between the tubing and casing. When injecting steam into thermal recovery wells in oilfields, high steam pressure and temperature are required, and the heat loss of steam from the wellhead to the formation should be minimal. To achieve this, high-temperature and high-pressure resistant thermal recovery packers are generally installed on the steam injection string above the formation to prevent steam from flowing into the casing and causing heat loss. There are many types of thermal recovery packers available, all of which utilize the thermally sensitive sheet on the packer to deform and open the rubber sleeve when the temperature rises above 300°C. The setting time is long, and the heat loss is large. The sealing performance during setting depends on the temperature of the injected steam. When the temperature of the injected steam drops, the thermally sensitive sheet shrinks, and the sealing effect between the rubber sleeve and the casing decreases accordingly. Utility Model Content

[0003] To address the problems of long setting time, large heat loss, and unstable sealing effect of current thermal recovery packers, this utility model provides a thermal recovery packer that can be set quickly.

[0004] The technical solution provided by this utility model is: a rapid-setting thermal recovery packer, including an upper connector and a lower connector. The lower part of the upper connector is provided with a central tube with a reduced diameter. A stepped surface A is formed between the central tube and the upper connector. The lower end of the central tube is threaded and sealed to the lower connector. The outer circle of the lower connector is fixedly connected to the cylinder liner by a pin and a sealing ring. A piston is provided between the cylinder liner and the central tube. The piston is in clearance fit with the cylinder liner and the central tube by a sealing ring. An air inlet is opened in the central tube below the sealing ring of the piston. An upper retaining ring, a rubber sleeve and a lower retaining ring are sequentially fitted on the central tube below the stepped surface A of the upper connector. The lower retaining ring presses on the top of the piston.

[0005] The central tube has an annular groove in the middle of the piston. A limiting component is installed in the annular groove. The limiting component includes an expansion sleeve, which is a hollow and closed elastic structure filled with heat-conducting oil. The expansion sleeve is fitted into the annular groove. Several support plates are bonded to the upper and lower end faces of the expansion sleeve. The support plates are evenly arranged around the circumference and are inserted into the upper and lower end faces of the annular groove. The piston has a receiving hole in the middle. Above the receiving hole, the piston has a stepped hole with a reduced diameter. A step surface B is formed between the stepped hole and the receiving hole. The inner diameter of the stepped hole is larger than the outer diameter formed by the support plates.

[0006] The beneficial effects of this utility model are as follows: This utility model sets the seal by injecting steam pressure instead of by expanding the seal with a heat-sensitive medium. The setting process is fast, reducing steam loss. It can quickly set the seal without waiting for the wellbore temperature to rise. By setting a limiting component, the rubber sleeve can maintain a stable seal within a certain temperature range. Changes in the pressure of the injected steam will not affect the setting effect. It also has the characteristic of rapid unsealing. Attached Figure Description

[0007] Appendix Figure 1 This is a schematic diagram of the structure of this utility model;

[0008] Appendix Figure 2 This is a schematic diagram of the structure of this utility model after it has been sealed.

[0009] Appendix Figure 3 This is a schematic diagram of the limiting component in this utility model;

[0010] Appendix Figure 4 This is a schematic diagram of the upper connector in this utility model;

[0011] Appendix Figure 5 This is a schematic diagram of the piston structure in this utility model.

[0012] In the diagram, 1-upper connector, 101-center tube, 102-step surface A, 103-ring groove, 2-lower connector, 3-rubber sleeve, 4-piston, 401-step hole, 402-accommodating hole, 403-step surface B, 5-limiting component, 501-expansion sleeve, 502-support plate, 6-cylinder liner, 7-pin, 8-lower retaining ring, 9-upper retaining ring, 10-inlet port. Detailed Implementation

[0013] As attached Figures 1-5 A rapid-setting thermal recovery packer includes an upper connector 1 and a lower connector 2. The lower part of the upper connector 1 is provided with a central tube 101 with a reduced diameter. A stepped surface A102 is formed between the central tube 101 and the upper connector 1. The lower end of the central tube 101 is threaded and sealed to the lower connector 2. The outer circle of the lower connector 2 is fixedly connected to the cylinder liner 6 by a pin 7 and a sealing ring. A piston 4 is provided between the cylinder liner 6 and the central tube 101. The piston 4 is in clearance fit with the cylinder liner 6 and the central tube 101 by a sealing ring. The central tube 101 has an air inlet 10 below the sealing ring of the piston 4. The central tube 101 is fitted with an upper retaining ring 9, a rubber sleeve 3 and a lower retaining ring 8 in sequence below the stepped surface A102 of the upper connector 1. The lower retaining ring 8 presses against the top of the piston 4.

[0014] The central tube 101 has an annular groove 103 in the middle of the piston 4. A limiting component 5 is installed in the annular groove 103. The limiting component 5 includes an expansion sleeve 501, which is a hollow and closed elastic structure. The expansion sleeve 501 is filled with heat-conducting oil and fits in the annular groove 103. Several support plates 502 are bonded to the upper and lower end faces of the expansion sleeve 501. The support plates 502 are evenly arranged around the circumference and are inserted into the upper and lower end faces of the annular groove 103. The piston 4 has a receiving hole 402 in the middle. The piston 4 has a stepped hole 401 with a reduced diameter above the receiving hole 402. A stepped surface B403 is formed between the stepped hole 401 and the receiving hole 402. The inner diameter of the stepped hole 401 is larger than the outer diameter formed by the support plates 502.

[0015] When the ambient temperature of the packer reaches 300°C, the outer diameter of the expansion sleeve 501 expands, and the support plate 502 moves outward as the upper end face of the expansion sleeve 501 extends. The support plate 502 extends into the stepped surface B403 of the piston 4. At the same time, the support plate 502 remains in the upper and lower end faces of the annular groove 103. At this time, the support plate 502 plays a limiting role for the piston 4. When the ambient temperature of the packer drops to 220°C, the expansion sleeve 501 retracts, and the support plate 502 and piston 4 are pulled out from the stepped surface B403.

[0016] During steam injection in oilfield thermal recovery wells, high-pressure steam enters the inlet 10, pushing the piston 4 upward. The piston 4 then pushes the lower retaining ring 8 upward, compressing and expanding the rubber sleeve 3 to tightly adhere to the casing, achieving a set seal. This invention utilizes the high pressure of injected steam for setting, resulting in rapid setting and reduced steam heat loss. When the injected steam and wellbore temperature rise, the heat transfer oil inside the expansion sleeve 501 undergoes thermal expansion. Under the action of the upper and lower limits of the support plate 502, the expansion sleeve 501 expands radially, increasing its outer diameter and causing the support plate 502 to move outward. 02 extends into the stepped surface B403 of piston 4, preventing piston 4 from descending. The injected steam is within the range of 220-300°C (this temperature range can be adjusted according to actual needs). The setting effect of the rubber sleeve 3 is stable, and changes in the pressure of the injected steam will not affect the setting effect. When unsealing is required, the steam injection is stopped. When the wellbore temperature drops to 220°C, the support plate 502 is pulled out from the stepped surface B403 of piston 4. Piston 4 loses support and descends. The rubber sleeve 3 retracts under its own elasticity to unseal quickly.

[0017] This invention uses steam injection for pressure setting instead of expansion setting via a heat-sensitive medium. The setting process is fast, and setting can be completed quickly without waiting for the wellbore temperature to rise. By setting the limiting component 5, the rubber sleeve 3 can maintain a stable seal within a certain temperature range, unaffected by changes in steam pressure, and also has the characteristic of rapid unsealing.

Claims

1. A rapid-setting thermal recovery packer, comprising an upper connector (1) and a lower connector (2), characterized in that: The lower part of the upper connector (1) is provided with a central tube (101) with a reduced diameter. A stepped surface A (102) is formed between the central tube (101) and the upper connector (1). The lower end of the central tube (101) is threaded and sealed to the lower connector (2). The outer circle of the lower connector (2) is fixedly connected to the cylinder liner (6) by a pin (7) and a sealing ring. A piston (4) is provided between the cylinder liner (6) and the central tube (101). The piston (4) is in clearance fit with the cylinder liner (6) and the central tube (101) by a sealing ring. The central tube (101) has an air inlet hole (10) below the sealing ring of the piston (4). The central tube (101) is fitted with an upper retaining ring (9), a rubber sleeve (3) and a lower retaining ring (8) in sequence below the stepped surface A (102) of the upper connector (1). The lower retaining ring (8) presses on the top of the piston (4).

2. The rapid-setting thermal recovery packer according to claim 1, characterized in that: The central tube (101) has an annular groove (103) in the middle of the piston (4). A limiting component (5) is installed in the annular groove (103). The limiting component (5) includes an expansion sleeve (501). The expansion sleeve (501) is a hollow and closed elastic structure. The expansion sleeve (501) is filled with heat-conducting oil. The expansion sleeve (501) is fitted in the annular groove (103). Several support plates (502) are bonded to the upper and lower ends of the expansion sleeve (501). 02) The support plates (502) are evenly arranged around the circumference and inserted into the upper and lower end faces of the annular groove (103). The piston (4) has a receiving hole (402) in the middle and a stepped hole (401) with a reduced diameter is opened above the receiving hole (402). A stepped surface B (403) is formed between the stepped hole (401) and the receiving hole (402). The inner diameter of the stepped hole (401) is larger than the outer diameter formed by each support plate (502).

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