High-efficiency sealed thermal recovery packer

Abstract

The application relates to a high-efficiency sealing thermal recovery packer, relating to the technical field of oilfield downhole tools. A sealing guarantee assembly, a spacer ring, a rubber sleeve and an unsealing sleeve are sequentially sleeved on a center pipe above a piston, the unsealing sleeve is in threaded connection with the center pipe, the threads for connecting the center pipe with an upper joint and a lower joint are right-handed threads, and the threads for connecting the unsealing sleeve with the center pipe are left-handed threads. The packer has the beneficial effects that the sealing guarantee assembly is arranged, the hollow sleeve is made to have high height growth by using the high-temperature environment of steam injection, the rubber sleeve is further extruded after the packer is set, even if the rubber sleeve layer is partially aged, the high-pressure extrusion can make the inner layer of non-aged rubber seal with the sleeve, and the reliability of the sealing is guaranteed.

Description

Technical Field

[0001] This invention relates to the field of oilfield downhole tools technology, and in particular to a high-efficiency sealing packer for thermal recovery. 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. 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 prematurely due to high temperatures. Ordinary packers use a setting mechanism to squeeze the rubber sleeve from top to bottom. After the rubber sleeve expands and sets, the setting mechanism locks in place. Due to the premature aging of the rubber sleeve during thermal recovery, leakage occurs between the rubber sleeve and the casing, resulting in heat loss. The leakage will continue to expand over time, eventually leading to packer failure. Summary of the Invention

[0003] To address the problems of low sealing performance and high heat loss in existing thermal recovery packers, this invention provides a high-efficiency sealing thermal recovery packer.

[0004] The technical solution provided by this invention is: a high-efficiency sealing thermal recovery packer, including an upper connector, a central tube connected to the lower part of the upper connector by a threaded seal, a lower connector connected to the lower part of the central tube by a threaded seal, a packer tube fixedly connected to the outer circle of the lower connector by a positioning pin, a transition fit between the packer tube and the lower connector by a sealing ring, a piston provided between the packer tube and the central tube, a clearance fit between the piston and the packer tube and the central tube by a sealing ring, a liquid inlet hole opened in the central tube below the sealing ring of the piston, an inner ring groove opened in the inner hole of the piston, an elastic open ring installed in the inner ring groove, and an outer ring groove opened in the central tube above the inner ring groove;

[0005] Above the piston, the central tube is fitted with a sealing and protection component, a spacer ring, a rubber sleeve, and a release sleeve in sequence. The release sleeve is threaded to the central tube. The threads connecting the central tube to the upper and lower connectors are right-hand threads, and the threads connecting the release sleeve to the central tube are left-hand threads.

[0006] The sealing and protection assembly includes a hollow sleeve, the outer circle and inner hole of which are machined into corrugated rings. The hollow sleeve contains three pull-down columns evenly distributed around its circumference. Each pull-down column includes a base welded to the bottom surface of the hollow sleeve. A pull-down tube is connected to the upper part of the base via bolts and a flange. The inner hole of the pull-down tube has a one-way toothed hole located at the top. An upper pull-down column is located above the pull-down column, and a one-way toothed column is located below the upper pull-down column. The one-way toothed column extends into the one-way toothed hole, and the engagement of the one-way toothed column with the one-way toothed hole allows the upper pull-down column to rise along the pull-down column but not descend. A segmented column is threadedly connected to the upper part of the one-way toothed column. A threaded hole is opened on the upper end face of the hollow sleeve. A load-bearing cap is fixedly connected to the upper part of the segmented column. The load-bearing cap is connected to the hollow sleeve via a threaded hole and a sealing ring. The hollow sleeve is filled with heat-conducting oil.

[0007] The central tube, above the piston, is sequentially fitted with a sealing and protection assembly, a spacer ring, a rubber sleeve, and a release sleeve. This is replaced with: the central tube, above the piston, is sequentially fitted with a sealing and protection assembly, a spacer ring, a heat insulation assembly, a rubber sleeve, and a release sleeve. The heat insulation assembly includes an I-shaped sleeve, with a corrugated sleeve welded to its outer side. The corrugated sleeve and the I-shaped sleeve form a sealed space, which is filled with heat-conducting oil. The upper and lower annular surfaces of the corrugated sleeve are provided with continuous corrugated rings. The outer circle of the I-shaped sleeve is concave inwards, and the upper end face of the I-shaped sleeve has a threaded hole. The I-shaped sleeve is sealed and connected to the oil filler cap through the threaded hole.

[0008] The natural state of an elastic open ring is between the inner ring groove and the outer ring groove.

[0009] An anti-rotation pin is inserted between the unsealing sleeve and the rubber tube, and the anti-rotation pin is arranged along the axial direction of the central tube.

[0010] The thread pitch of the connecting threads of the segmented column and the one-way toothed column is the same as that of the connecting threads of the load-bearing cover and the hollow sleeve.

[0011] The beneficial effects of the present invention are as follows: By setting up a sealing and protection component, the present invention utilizes the high temperature environment of steam injection to increase the height of the hollow sleeve. After the packer is set, the rubber tube is further squeezed. Even if the outer layer of the rubber tube is aged, the high-pressure squeezing can ensure that the unaged rubber in the inner layer of the rubber tube can seal with the sleeve, thus ensuring the reliability of the seal.

[0012] The increase in the height of the hollow sleeve pulls the upper pull column upward. Due to the structure of the one-way toothed column and the one-way toothed hole, the one-way toothed column cannot descend further. That is, the height of the hollow sleeve can only increase and cannot decrease. This structure allows the sealing protection component to still compress the rubber cylinder and ensure sealing performance even when the surrounding temperature drops during the packer's shutdown period.

[0013] When steam is injected into the insulation component, the high temperature causes the heat-conducting oil inside the corrugated sleeve to expand. The corrugated sleeve expands outward to approach or adhere to the sleeve, separating the rubber sleeve from the high temperature and improving the service life and sealing performance of the rubber sleeve. Attached Figure Description

[0014] Appendix Figure 1 This is a schematic diagram of the structure of the present invention;

[0015] Appendix Figure 2 This is a structural schematic diagram of the sealing and protection component;

[0016] Appendix Figure 3 This is a structural diagram of the pull-up column;

[0017] Appendix Figure 4 This is a schematic diagram of the pull-down column structure;

[0018] Appendix Figure 5 This is a schematic diagram of the thermal insulation component;

[0019] Appendix Figure 6 This is a schematic diagram of the central tube structure;

[0020] Appendix Figure 7 This is a schematic diagram of the piston structure.

[0021] In the diagram: 1-Upper connector, 2-Central tube, 201-Outer ring groove, 202-Inlet hole, 3-Roll tube, 4-Lower connector, 5-Piston, 501-Inner ring groove, 6-Package tube, 7-Sealing protection assembly, 701-Hollow sleeve, 7011-Wavering ring, 702-Pull-down column, 7021-Base, 7022-Pull-down tube, 7023-One-way toothed hole, 703-Pull-up column, 7031-One-way toothed column, 7032-Segmented column, 704-Bearing cap, 8-Insulation assembly, 801-I-shaped sleeve, 802-Corrugated sleeve, 8021-Corrugated ring, 803-Oil filler cap, 9-Spacer ring, 10-Unsealing sleeve, 11-Elastic open ring, 12-Anti-rotation pin, 13-Positioning pin. Detailed Implementation

[0022] like Figures 1-7 As shown, a high-efficiency sealing thermal recovery packer includes an upper connector 1, a central tube 2 with a threaded seal connection at the lower part of the upper connector 1, a lower connector 4 with a threaded seal connection at the lower part of the central tube 2, a packer tube 6 with a fixed connection on the outer circle of the lower connector 4 by a positioning pin 13, a transition fit between the packer tube 6 and the lower connector 4 by a sealing ring, a piston 5 between the packer tube 6 and the central tube 2, a clearance fit between the piston 5 and the packer tube 6 and the central tube 2 by a sealing ring, an inlet hole 202 in the central tube 2 below the sealing ring of the piston 5, an inner ring groove 501 in the inner hole of the piston 5, an elastic open ring 11 installed in the inner ring groove 501, and an outer ring groove 201 in the central tube 2 above the inner ring groove 501.

[0023] Above the piston 5, the central tube 2 is sequentially fitted with a sealing and protection component 7, a spacer ring 9, a rubber sleeve 3, and a release sleeve 10. The release sleeve 10 is threaded to the central tube 2. The threads connecting the central tube 2 to the upper connector 1 and the lower connector 4 are right-hand threads, and the threads connecting the release sleeve 10 to the central tube 2 are left-hand threads.

[0024] The sealing component 7 includes a hollow sleeve 701. Both the outer circumference and inner hole of the hollow sleeve 701 are machined into wave-shaped rings 7011. A pull-down post 702 is provided inside the hollow sleeve 701, with three pull-down posts 702 evenly distributed around the circumference. Each pull-down post 702 includes a base 7021, which is welded to the bottom surface of the hollow sleeve 701. A pull-down tube 7022 is connected to the upper part of the base 7021 via bolts and a flange. A one-way toothed hole 7023 is machined into the inner hole of the pull-down tube 7022, located at the top of the pull-down tube 7022. The upper part of the pull-down post 702 is equipped with… There is an upper pull column 703, and a one-way toothed column 7031 is provided at the lower part of the upper pull column 703. The one-way toothed column 7031 extends into the one-way toothed hole 7023. The one-way toothed column 7031 and the one-way toothed hole 7023 cooperate to allow the upper pull column 703 to rise along the lower pull column 702 but not to descend. The upper part of the one-way toothed column 7031 is threadedly connected to the segment column 7032. The upper end face of the hollow sleeve 701 has a threaded hole. The upper part of the segment column 7032 is fixedly connected to the load-bearing cover 704. The load-bearing cover 704 is connected to the hollow sleeve 701 through the threaded hole and the sealing ring. The hollow sleeve 701 is filled with heat-conducting oil.

[0025] The central tube 2 is sequentially fitted with a sealing and protection component 7, a spacer ring 9, a rubber sleeve 3, and a release sleeve 10 above the piston 5. This is replaced by: the central tube 2 being sequentially fitted with a sealing and protection component 7, a spacer ring 9, a heat insulation component 8, a rubber sleeve 3, and a release sleeve 10 above the piston 5. The heat insulation component 8 includes an I-shaped sleeve 801, with a corrugated sleeve 802 welded to its outer side. The corrugated sleeve 802 and the I-shaped sleeve 801 form a sealed space, which is filled with heat-conducting oil. The upper and lower annular surfaces of the corrugated sleeve 802 are provided with continuous corrugated rings 8021. The outer circle of the I-shaped sleeve 801 is concave inwards, and a threaded hole is opened on the upper end face of the I-shaped sleeve 801. The I-shaped sleeve 801 is sealed and connected to the oil filler cap 803 through the threaded hole.

[0026] The natural state of the elastic open ring 11 is between the inner ring groove 501 and the outer ring groove 201.

[0027] An anti-rotation pin 12 is inserted between the unsealing sleeve 10 and the rubber tube 3, and the anti-rotation pin 12 is arranged along the axial direction of the central tube 2.

[0028] The packer is lowered into the injection-production formation, the tubing is pressurized, and the high-pressure liquid pushes the piston 5 upward. The rise of piston 5 pushes the sealing and protection components 7 and the spacer ring 9 upward, squeezing the rubber sleeve 3 to expand. The piston 5 rises until the elastic open ring 11 falls between the inner ring groove 501 and the outer ring groove 201 for positioning, and the rubber sleeve 3 is set. When steam is injected, the high-temperature steam causes the heat transfer oil in the hollow sleeve 701 to expand. The wave ring 7011 structure of the hollow sleeve 701 causes the hollow sleeve 701 to undergo axial elastic deformation, increasing the height of the hollow sleeve 701 and further squeezing the rubber sleeve 3. Even if the outer layer of the rubber sleeve 3 is aged, the high-pressure squeezing can still ensure that the unaged rubber in the inner layer of the rubber sleeve 3 seals with the sleeve, ensuring the reliability of the seal.

[0029] As the hollow sleeve 701 increases in height, it pulls the upper pull column 703 upward. Due to the structure of the one-way toothed column 7031 and the one-way toothed hole 7023, the one-way toothed column 7031 cannot descend further. That is, the height of the hollow sleeve 701 can only increase and cannot decrease. This structure allows the sealing protection component 7 to still compress the rubber cylinder 3 after the ambient temperature drops during the packer's shutdown period, thus ensuring sealing performance.

[0030] When steam is injected, the high temperature causes the heat-conducting oil inside the corrugated sleeve 802 to expand. The corrugated sleeve 802 expands outward to approach or fit against the sleeve, separating the rubber sleeve 3 from the high temperature and improving the service life and sealing performance of the rubber sleeve 3.

[0031] When unsealing, the tubing is rotated in the opposite direction. Under the action of the left-hand thread between the unsealing sleeve 10 and the central tube 2, the unsealing sleeve 10 rises, the rubber sleeve 3 loses pressure, and retracts under its own elasticity to unseal.

[0032] The threads connecting the segmented column 7032 and the one-way toothed column 7031 have the same pitch as the threads connecting the load-bearing cover 704 and the hollow sleeve 701. During installation, first insert the one-way toothed column 7031 into the one-way toothed hole 7023 of the pull-down tube 7022 from the bottom, and tap the one-way toothed column 7031 upwards so that the one-way toothed column 7031 and the one-way toothed hole 7023 retain two to three matching teeth. Then, connect the pull-down tube 7022 and the base 7021 together with bolts, inject heat transfer oil into the hollow sleeve 701, and then tighten the threads of the load-bearing cover 704 to seal it. At the same time, the segmented column 7032 and the one-way toothed column 7031 are threaded together.

Claims

1. A high-efficiency sealing thermal recovery packer, comprising an upper connector (1), characterized in that: The upper connector (1) is threadedly connected to the center tube (2) at the bottom. The center tube (2) is threadedly connected to the lower connector (4) at the bottom. The outer circle of the lower connector (4) is fixedly connected to the packer tube (6) by a positioning pin (13). The packer tube (6) and the lower connector (4) are transitionally fitted by a sealing ring. A piston (5) is provided between the packer tube (6) and the center tube (2). The piston (5) is fitted with the packer tube (6) and the center tube (2) by a sealing ring clearance. The center tube (2) has an inlet hole (202) below the sealing ring of the piston (5). The piston (5) has an inner ring groove (501) in its inner hole. An elastic open ring (11) is installed in the inner ring groove (501). The center tube (2) has an outer ring groove (201) above the inner ring groove (501). The central tube (2) is fitted with a sealing and protection assembly (7), a spacer ring (9), a heat insulation assembly (8), a rubber sleeve (3), and a release sleeve (10) in sequence above the piston (5). The release sleeve (10) is threaded to the central tube (2). The threads connecting the central tube (2) to the upper connector (1) and the lower connector (4) are right-hand threads, and the threads connecting the release sleeve (10) to the central tube (2) are left-hand threads. The sealing and protection assembly (7) includes a hollow sleeve (701). The outer circle and inner hole of the hollow sleeve (701) are both machined into wave rings (7011). The hollow sleeve (701) is provided with pull-down columns (702). The number of pull-down columns (702) is three evenly distributed around the circumference. The pull-down column (702) includes a base (7021). The base (7021) is welded to the bottom surface of the hollow sleeve (701). The upper part of the base (7021) is connected to the pull-down tube (7022) by bolts and flanges. The inner hole of the pull-down tube (7022) is machined with a one-way toothed hole (7023). The one-way toothed hole (7023) is located at the top of the pull-down tube (7022). The upper part of the pull-down column (702) An upper pull column (703) is provided, and a one-way toothed column (7031) is provided at the lower part of the upper pull column (703). The one-way toothed column (7031) extends into the one-way toothed hole (7023). The one-way toothed column (7031) and the one-way toothed hole (7023) cooperate to allow the upper pull column (703) to rise along the lower pull column (702) but not to descend. The upper part of the one-way toothed column (7031) is threadedly connected to a segment column (7032). A threaded hole is opened on the upper end face of the hollow sleeve (701). The upper part of the segment column (7032) is fixedly connected to a load-bearing cover (704). The load-bearing cover (704) is connected to the hollow sleeve (701) through a threaded hole and a sealing ring. The hollow sleeve (701) is filled with heat-conducting oil.

2. The high-efficiency sealing thermal recovery packer according to claim 1, characterized in that: The heat insulation component (8) includes an I-shaped sleeve (801), a corrugated sleeve (802) welded to the outside of the I-shaped sleeve (801), the corrugated sleeve (802) and the I-shaped sleeve (801) forming a sealed space, the sealed space formed by the corrugated sleeve (802) and the I-shaped sleeve (801) is filled with heat-conducting oil, the upper and lower ring surfaces of the corrugated sleeve (802) are provided with continuous corrugated rings (8021), the outer circle of the I-shaped sleeve (801) is recessed inward, the upper end face of the I-shaped sleeve (801) is provided with a threaded hole, and the I-shaped sleeve (801) is sealed and connected to the oil filler cap (803) through the threaded hole.

3. The high-efficiency sealing thermal recovery packer according to claim 1, characterized in that: The natural state of the elastic open ring (11) is between the inner ring groove (501) and the outer ring groove (201).

4. The high-efficiency sealing thermal recovery packer according to claim 1, characterized in that: An anti-rotation pin (12) is inserted between the unsealing sleeve (10) and the rubber tube (3), and the anti-rotation pin (12) is arranged axially along the central tube (2).

5. The high-efficiency sealing thermal recovery packer according to claim 1, characterized in that: The threads connecting the segmented post (7032) and the one-way toothed post (7031) have the same pitch as the threads connecting the load-bearing cap (704) and the hollow sleeve (701).

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