Efficient thermal recovery packer

Abstract

The invention discloses an efficient thermal recovery packer, and relates to the technical field of oil field downhole tools. The upper cooler and the lower cooler are both of a heat pipe structure, the upper cooler and the lower cooler are both of a closed cavity structure, capillary objects are bonded to the inner wall of a cavity, the cavity is filled with working fluid, and air pressure in the cavity is in a negative pressure state. The device has the beneficial effects that the outer circle of the lower cooling disc expands when the lower cooling disc is heated, the outer circle of the lower cooling disc is elastically attached to the inner wall of the sleeve, steam can be directly blocked on the lower side of the rubber barrel, meanwhile, the lower cooling disc makes direct contact with the sleeve and can exchange heat with the sleeve below the rubber barrel, and the temperature of the sleeve making contact with the rubber barrel is reduced; the temperature of the rubber sleeve is further reduced, the sealing performance of the rubber sleeve is improved, the service life of the rubber sleeve is prolonged, an annular groove in the outer circle of the lower cooling disc enables an annular space to be formed between the lower cooling disc and the sleeve, and heat insulation and elastic connection are facilitated.

Description

Technical Field

[0001] This invention relates to the field of oilfield downhole tool technology, and more particularly to a high-efficiency thermal recovery packer. Background Technology

[0002] Thermal recovery packers are common and critical downhole tools in heavy oil extraction, used for sealing steam injection wells and stratified steam injection. Thermal recovery packers need to withstand high temperatures and pressures and have high performance requirements. After each steam injection, the well needs to be shut down for a period of time to allow the viscosity of the heavy oil to be sufficiently reduced before extraction. Repeated long-term steam injections and well shut-downs cause the packer's rubber sleeve to age, and leaks will occur between the rubber sleeve and the casing. The leaks will continue to expand over time, eventually leading to packer failure. Summary of the Invention

[0003] To address the problem that current thermal recovery packers cannot maintain a seal for a long time, this invention provides a high-efficiency thermal recovery packer.

[0004] The technical solution provided by this invention is: a high-efficiency thermal recovery packer, including an upper connector and a lower connector. The upper connector is threadedly sealed to a central tube, and the lower part of the central tube is threadedly sealed to a lower connector. A cylinder liner extends upward from the outer circle of the lower connector. A piston is provided between the cylinder liner and the central tube. The piston, the cylinder liner, and the central tube are connected by a clearance fit through a sealing assembly. The central tube has a liquid inlet hole at the lower part of the sealing assembly of the piston. An inner heat insulation sleeve is fitted around the outside of the central tube. The inner heat insulation sleeve is positioned at the bottom of the upper connector. The upper part of the inner heat insulation sleeve has a flange for positioning. An upper cooler and a lower cooler are fitted around the outside of the inner heat insulation sleeve. The upper cooler has two upper cooling plates, and the lower cooler has two lower cooling plates. The upper cooler has an outer contact sleeve, and the lower cooler has an inner contact sleeve. The outer contact sleeve and the inner contact sleeve are inserted together. Two nuts are threaded to the lower part of the inner heat insulation sleeve. The two nuts are blocked at the bottom of the lower cooling plates. An outer heat insulation sleeve is fitted around the outer contact sleeve and the inner contact sleeve. A rubber sleeve is fitted around the outer heat insulation sleeve. The upper part of the outer heat insulation sleeve has a flange that is sandwiched between the rubber sleeve and the upper cooling plate. Both the upper and lower coolers are heat pipe structures: both the upper and lower coolers are closed cavity structures with capillary material adhering to the inner wall of the cavity, the cavity is filled with working fluid, and the air pressure inside the cavity is in a negative pressure state. The piston is fixedly connected to a push rod, which is arranged in four evenly circumferences. The lower cooling plate has a through hole at the push rod position. The push rod passes through the through hole and rests on the bottom of the spacer ring. The spacer ring is installed under the rubber sleeve, and the inner hole of the spacer ring is clearance-fitted with the outer heat insulation sleeve.

[0005] The central tube extends outward from the top rod section with a support shaft. The support shaft rests on the lower part of the inner insulation sleeve. The support shaft has an upper section hole and a lower section hole at the top rod section. The upper section hole is larger than the lower section hole. The top rod passes through the upper section hole and the lower section hole. An expansion tube is installed in the upper section hole. The expansion tube is made of polyethylene material. A locking sleeve is provided at the lower part of the expansion tube. The locking sleeve rests at the bottom of the upper section hole. The upper part of the support shaft is connected to a pressure cap by bolts. The pressure cap presses on the upper part of the expansion tube. The locking sleeve is made of elastic metal. The upper part of the locking sleeve is a tapered conical surface that tapers upward. There are six evenly distributed slits on the circumference of the locking sleeve. The inner hole of the locking sleeve is machined into a continuous one-way toothed ring. The direction of the one-way toothed ring is such that when the inner hole of the locking sleeve tapers and wraps around the top rod, the one-way toothed ring causes the top rod to move only upward. The central tube has several heat-conducting grooves at the support shaft position, which extend to the vicinity of the upper section hole.

[0006] The lower cooling plate has an annular groove on its outer circumference, and both the upper and lower end faces of the lower cooling plate have an annular corrugated structure. The upper cooling plate has the same structure.

[0007] In use, two high-efficiency thermal recovery packers are used simultaneously, with the upper high-efficiency thermal recovery packer sleeve installed above the piston and the lower high-efficiency thermal recovery packer sleeve installed below the piston.

[0008] The lower part of the locking sleeve has a stepped hole, and the slit is cut downwards to the stepped hole.

[0009] The piston has two annular grooves on its outer circumference and inner bore. High-temperature resistant packing is inserted into the annular grooves. A baffle is provided at the bottom of the packing. A pressure channel is opened inside the piston, which connects the two annular grooves and the pressure-bearing surface of the piston.

[0010] Several gaskets are provided between the gland and the expansion tube.

[0011] The beneficial effects of the present invention are as follows: 1. An upper cooler and a lower cooler are set at the top and bottom of the rubber tube. Taking advantage of the heat transfer characteristics of the heat pipe, the heat transfer inside the heat pipe mainly relies on the vapor-liquid phase change of the working liquid. The thermal resistance is very small, so it has a high thermal conductivity. The lower cooler transfers the heat of the vapor at the bottom of the rubber tube to the upper cooler, and the upper cooler dissipates the heat, thereby reducing the external ambient temperature of the rubber tube. 2. Due to the annular corrugated structure on the upper and lower end faces of the lower cooling plate, the outer circle of the lower cooling plate expands when heated. The outer circle of the lower cooling plate elastically adheres to the inner wall of the sleeve, which can directly block the steam on the lower side of the rubber sleeve. At the same time, the lower cooling plate is in direct contact with the sleeve, and can directly exchange heat with the sleeve below the rubber sleeve, that is, lower the temperature of the sleeve in contact with the rubber sleeve, further reducing the temperature of the rubber sleeve, improving the sealing performance and service life of the rubber sleeve. The annular groove on the outer circle of the lower cooling plate forms an annular space between the lower cooling plate and the sleeve, which is beneficial for heat insulation and elastic connection. 3. The locking mechanism consists of a support shaft, an expansion tube, and a locking sleeve, which can lock the top rod at a set temperature, allowing the rubber sleeve to be stably sealed with the sleeve within a certain temperature range. At this time, the seal of the rubber sleeve is not affected by changes in the injected steam pressure. At the same time, the unsealing temperature is high, the speed is fast, and the operation efficiency is high. Attached Figure Description

[0012] Appendix Figure 1 This is a schematic diagram of the structure of the present invention; Appendix Figure 2 It is attached Figure 1 Enlarged view of point A; Appendix Figure 3 It is attached Figure 1 Enlarged view of point B; Appendix Figure 4 It is attached Figure 1 Enlarged view of point C; Appendix Figure 5 This is a schematic diagram of the central tube in this invention; Appendix Figure 6 This is a schematic diagram showing the connection between the upper cooler and the lower cooler in this invention; Appendix Figure 7 This is a schematic diagram of the locking sleeve in this invention; Appendix Figure 8 This is a perspective view of the locking sleeve in this invention; Appendix Figure 9 This is an installation diagram of the present invention.

[0013] In the diagram, 1-upper connector, 2-lower connector, 201-cylinder liner, 3-center tube, 301-support shaft, 302-upper section hole, 303-lower section hole, 304-heat conduction groove, 305-liquid inlet hole, 4-piston, 401-packing, 402-partition plate, 403-pressure channel, 5-push rod, 6-rubber sleeve, 7-gasket, 8-inner heat insulation sleeve, 9-upper cooler, 901-upper cooling plate, 902-outer contact sleeve. 10-Outer heat insulation sleeve, 11-Spacer ring, 12-Lower cooler, 1201-Lower cooling plate, 1202-Inner contact sleeve, 1203-Through hole, 13-Nut, 14-Capillary material, 15-Glander cap, 16-Expansion tube, 17-Locking sleeve, 1701-Conical surface, 1702-Slit, 1703-One-way toothed ring, 1704-Stepped hole, 18-Sleeve, 19-Annular groove, 20-Annular corrugation. Detailed Implementation

[0014] like Figures 1-9A high-efficiency thermal recovery packer includes an upper connector 1 and a lower connector 2. The upper connector 1 is threadedly sealed to a central tube 3. The lower part of the central tube 3 is threadedly sealed to the lower connector 2. A cylinder liner 201 extends upward from the outer circle of the lower connector 2. A piston 4 is provided between the cylinder liner 201 and the central tube 3. The piston 4 is connected to the cylinder liner 201 and the central tube 3 through a clearance fit of a sealing assembly. The central tube 3 has a liquid inlet hole 305 at the lower part of the sealing assembly of the piston 4. An inner heat insulation sleeve 8 is fitted on the outside of the central tube 3. The inner heat insulation sleeve 8 is positioned at the bottom of the upper connector 1. The upper part of the inner heat insulation sleeve 8 has a flange for positioning. An upper cooler 9 and a lower cooler 12 are fitted on the outside of the inner heat insulation sleeve 8. The upper cooler 9 is provided with two upper cooling plates 901, and the lower cooler 12 is provided with two lower cooling plates 1201. The upper cooler 9 is provided with an outer contact sleeve 902, and the lower cooler 12 is provided with an inner contact sleeve 1202. The outer contact sleeve 902 and the inner contact sleeve 1202 are inserted together. Two nuts 13 are threaded to the lower part of the inner heat insulation sleeve 8. The two nuts 13 are blocked at the bottom of the lower cooling plates 1201. An outer heat insulation sleeve 10 is fitted on the outside of the outer contact sleeve 902 and the inner contact sleeve 1202. A rubber sleeve 6 is fitted on the outside of the outer heat insulation sleeve 10. The upper part of the outer heat insulation sleeve 10 has a flange that is sandwiched between the rubber sleeve 6 and the upper cooling plate 901. Both the upper cooler 9 and the lower cooler 12 are heat pipe structures: both the upper cooler 9 and the lower cooler 12 are closed cavity structures, the inner wall of the cavity is adhered with capillary material 14, the cavity is filled with working fluid, and the air pressure inside the cavity is in a negative pressure state. The piston 4 is fixedly connected to the push rod 5. The number of push rods 5 is four evenly arranged in a circle. The lower cooling plate 1201 has a through hole 1203 at the position of the push rod 5. The push rod 5 passes through the through hole 1203 upward and hits the spacer ring 11 below. The spacer ring 11 is installed below the rubber sleeve 6. The inner hole of the spacer ring 11 is clearance-fitted with the outer heat insulation sleeve 10.

[0015] The central tube 3 extends outward from the top rod 5 by a support shaft 301. The support shaft 301 rests against the lower part of the inner insulation sleeve 8. The support shaft 301 has an upper section hole 302 and a lower section hole 303 at the top rod 5. The upper section hole 302 is larger than the lower section hole 303. The top rod 5 passes through the upper section hole 302 and the lower section hole 303. An expansion tube 16 is installed in the upper section hole 302. The expansion tube 16 is made of polyethylene material. A locking sleeve 17 is provided at the lower part of the expansion tube 16. The locking sleeve 17 rests at the bottom of the upper section hole 302. The upper part of the support shaft 301 is connected to the pressure cap 15 by bolts. The pressure cap 15 presses on the upper part of the expansion tube 16. The locking sleeve 17 is made of elastic metal. The upper part of the locking sleeve 17 is a tapered surface 1701 that tapers upwards. The locking sleeve 17 has six evenly distributed slits 1702 in the circumferential direction. The inner hole of the locking sleeve 17 is machined into a continuous one-way toothed ring 1703. The direction of the one-way toothed ring 1703 is such that when the inner hole of the locking sleeve 17 tapers and wraps around the push rod 5, the one-way toothed ring 1703 makes the push rod 5 only move upwards. The central tube 3 has several heat-conducting grooves 304 at the support shaft 301 position. The heat-conducting grooves 304 extend to the vicinity of the upper section hole 302 to increase the temperature of the support shaft 301.

[0016] The support shaft 301, expansion tube 16, and locking sleeve 17 form a locking mechanism that can lock the top rod 5 at a set temperature, so that the rubber sleeve 6 can stably seal with the sleeve 18 within a certain temperature range. At this time, the seal of the rubber sleeve 6 is not affected by the change of injected steam pressure, and the unsealing temperature is high and the speed is fast.

[0017] The lower cooling plate 1201 has an annular groove 19 on its outer circumference, and the upper and lower end faces of the lower cooling plate 1201 are provided with an annular corrugated structure 20. The upper cooling plate 901 has the same structure.

[0018] An upper cooler 9 and a lower cooler 12 are installed above and below the rubber sleeve 6. Utilizing the heat transfer characteristics of the heat pipe, the lower cooler 12 transfers the heat of the steam at the bottom of the rubber sleeve 6 to the upper cooler 9, which then dissipates the heat, thereby reducing the external ambient temperature of the rubber sleeve 6. Due to the annular corrugated structure 20 on the upper and lower end faces of the lower cooling plate 1201, the outer circle of the lower cooling plate 1201 expands when heated, and the outer circle of the lower cooling plate 1201 elastically adheres to the inner wall of the sleeve 18, directly blocking the steam on the lower side of the rubber sleeve 6. At the same time, the lower cooling plate 1201 is in direct contact with the sleeve 18, which can exchange heat with the sleeve 18 below the rubber sleeve 6, thereby lowering the temperature of the sleeve 18 in contact with the rubber sleeve 6, further reducing the temperature of the rubber sleeve 6, improving the sealing performance and service life of the rubber sleeve 6. The annular groove 19 on the outer circle of the lower cooling plate 1201 forms an annular space between the lower cooling plate 1201 and the sleeve 18, which is beneficial for heat insulation and elastic connection.

[0019] In use, two high-efficiency thermal recovery packers are used simultaneously, with the upper high-efficiency thermal recovery packer rubber sleeve 6 installed above the piston 4 and the lower high-efficiency thermal recovery packer rubber sleeve 6 installed below the piston 4, so that the expansion tube 16 is in the steam heating position, thus completing the task of locking the top rod 5 and the rubber sleeve 6.

[0020] The lower part of the locking sleeve 17 has a stepped hole 1704, and the slit 1702 extends downward to the stepped hole 1704, making the inner hole of the locking sleeve 17 more uniform when it shrinks.

[0021] The piston 4 has two annular grooves on its outer circumference and inner hole. Packing material 401 is inserted into the annular grooves. A baffle plate 402 is provided at the bottom of the packing material 401. A pressure channel 403 is provided inside the piston 4. The pressure channel 403 connects the two annular grooves and the pressure-bearing surface of the piston 4. Steam pressure can act on the baffle plate 402 through the pressure channel 403. The baffle plate 402 compresses the packing material 401 outward, resulting in a better sealing effect.

[0022] Several gaskets 7 are provided between the pressure cap 15 and the expansion tube 16. The number of gaskets 7 can be changed as needed to change the length of the expansion tube 16, thereby adjusting the expansion tube 16 to expand within a certain temperature range and compressing the locking sleeve 17 to retract the locking rod 5.

[0023] A compression spring is provided between the piston 4 and the support shaft 301. When the temperature drops to the unsealing set temperature, the locking sleeve 17 releases the push rod 5, and the piston 4 can then descend under the action of the compression spring.

[0024] After the high-efficiency thermal recovery packer is lowered into the well, high-pressure steam is introduced into the tubing string. The high-pressure steam pushes piston 4 and push rod 5 upward, pushing spacer ring 11 upward. The rubber sleeve 6 is compressed and expands, settling against the inner wall of casing 18. When the downhole temperature reaches above the set value, expansion tube 16 expands and elongates, compression locking sleeve 17 contracts, and locking sleeve 17 locks push rod 5, preventing it from descending, thus fixing the seal of rubber sleeve 6. Above the set temperature, temperature changes will not cause changes in the sealing performance of rubber sleeve 6. The temperature set in this application... The temperature is 260°C. When the temperature of the high-efficiency thermal recovery packer reaches above 260°C due to steam injection, the rubber sleeve 6 is locked and sealed. When leakage occurs in the seal of the rubber sleeve 6, the steam pressure can be increased to make the piston 4 and the push rod 5 continue to rise, increasing the expansion degree of the rubber sleeve 6 and improving the sealing effect. When unsealing, the temperature is below 260°C, the expansion tube 16 contracts, the locking sleeve 17 can release the push rod 5, the piston 4 descends under the action of the compression spring and its own weight, and the rubber sleeve 6 retracts to unseal, which is rapid.

Claims

1. A high-efficiency thermal recovery packer, comprising an upper connector (1) and a lower connector (2), characterized in that: The upper connector (1) is threadedly sealed to the central tube (3), and the lower part of the central tube (3) is threadedly sealed to the lower connector (2). The outer circle of the lower connector (2) extends upward to form a cylinder liner (201). A piston (4) is provided between the cylinder liner (201) and the central tube (3). The piston (4) is connected to the cylinder liner (201) and the central tube (3) through a clearance fit of the sealing assembly. The central tube (3) has a liquid inlet hole (305) at the lower part of the sealing assembly of the piston (4). The center tube (3) is fitted with an inner heat insulation sleeve (8), which rests on the lower part of the upper connector (1). The upper part of the inner heat insulation sleeve (8) has a flange for positioning. The outer side of the inner heat insulation sleeve (8) is fitted with an upper cooler (9) and a lower cooler (12). The upper cooler (9) is provided with two upper cooling plates (901), and the lower cooler (12) is provided with two lower cooling plates (1201). The upper cooler (9) is provided with an outer contact sleeve (902), and the lower cooler (12) is provided with an inner contact sleeve (1201). 202), the outer contact sleeve (902) and the inner contact sleeve (1202) are inserted together. The lower part of the inner heat insulation sleeve (8) is threaded with two nuts (13). The two nuts (13) are blocked at the lower part of the lower cooling plate (1201). The outer contact sleeve (902) and the inner contact sleeve (1202) are covered with an outer heat insulation sleeve (10). The outer heat insulation sleeve (10) is covered with a rubber sleeve (6). The upper part of the outer heat insulation sleeve (10) has a flange that is sandwiched between the rubber sleeve (6) and the upper cooling plate (901). The upper cooler (9) and the lower cooler (12) are both heat pipe structures: the upper cooler (9) and the lower cooler (12) are both closed cavity structures, the inner wall of the cavity is adhered with capillary material (14), the cavity is filled with working fluid, and the air pressure in the cavity is in a negative pressure state. The piston (4) is fixedly connected to the top rod (5). The number of top rods (5) is four evenly arranged in circles. The lower cooling plate (1201) has a through hole (1203) at the position of the top rod (5). The top rod (5) passes through the through hole (1203) upward and hits the spacer (11) below. The spacer (11) is installed below the rubber sleeve (6). The inner hole of the spacer (11) is clearance-fitted with the outer heat insulation sleeve (10).

2. The high-efficiency thermal recovery packer according to claim 1, characterized in that: The central tube (3) extends outward from the top rod (5) by a support shaft (301). The support shaft (301) rests against the lower part of the inner heat insulation sleeve (8). The support shaft (301) has an upper section hole (302) and a lower section hole (303) at the top rod (5). The upper section hole (302) is larger than the lower section hole (303). The top rod (5) passes through the upper section hole (302) and the lower section hole (303). An expansion tube (16) is installed in the upper section hole (302). The expansion tube (16) is made of polyethylene material. A locking sleeve (17) is provided at the lower part of the expansion tube (16). The locking sleeve (17) falls into the upper section hole (302). At the bottom, the upper part of the support shaft (301) is connected to the pressure cap (15) by bolts. The pressure cap (15) presses on the upper part of the expansion tube (16). The locking sleeve (17) is made of elastic metal. The upper part of the locking sleeve (17) is a conical surface (1701) that shrinks upward. The locking sleeve (17) has six evenly distributed slits (1702) in the circumferential direction. The inner hole of the locking sleeve (17) is processed into a continuous one-way toothed ring (1703). The direction of the one-way toothed ring (1703) is: when the inner hole of the locking sleeve (17) shrinks and wraps around the top rod (5), the one-way toothed ring (1703) makes the top rod (5) only move upward. The central tube (3) has several heat-conducting grooves (304) at the support shaft (301) position, and the heat-conducting grooves (304) extend to the vicinity of the upper section hole (302).

3. The high-efficiency thermal recovery packer according to claim 1, characterized in that: The lower cooling plate (1201) has an annular groove (19) on its outer circle, and the upper and lower end faces of the lower cooling plate (1201) are provided with an annular corrugated (20) structure. The upper cooling plate (901) has the same structure.

4. The high-efficiency thermal recovery packer according to claim 1, characterized in that: When in use, two high-efficiency thermal recovery packers are used simultaneously, with the upper high-efficiency thermal recovery packer sleeve (6) installed above the piston (4) and the lower high-efficiency thermal recovery packer sleeve (6) installed below the piston (4).

5. The high-efficiency thermal recovery packer according to claim 1, characterized in that: The lower part of the locking sleeve (17) has a stepped hole (1704), and the slit (1702) extends downward to the stepped hole (1704).

6. The high-efficiency thermal recovery packer according to claim 1, characterized in that: The piston (4) has two annular grooves on its outer circle and inner hole. The annular grooves are filled with packing material (401). The bottom of the packing material (401) is provided with a partition plate (402). The piston (4) has a pressure channel (403) inside. The pressure channel (403) connects the two annular grooves and the pressure-bearing surface of the piston (4).

7. A high-efficiency thermal recovery packer according to claim 2, characterized in that: Several gaskets (7) are provided between the gland (15) and the expansion tube (16).

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