Thermal recovery packer

Abstract

The present invention belongs to the technical field of well plugging, and specifically relates to a thermal recovery packer. The thermal recovery packer includes an upper joint, a center tube, a lower joint, and an outer tube. The lower joint and the center tube form an annular piston cavity, and an annular piston is installed in the annular piston cavity in a sliding and sealing manner along the up and down directions. The tube wall of the center tube is provided with a connecting hole that is connected to the annular piston cavity and is located below the annular piston. The annular piston is externally sleeved with a rubber tube, and a conical support section of the annular piston can be inserted into the rubber tube and make the rubber tube radially expand outward to seal; a locking buckle is provided on the inner wall of the annular piston, and a locking ring seat is correspondingly provided on the outer wall of the center tube. An unsealing ring is installed on the locking ring seat through a second pin, and the locking ring seat has a downward annular step, and the annular step and the unsealing ring are spaced up and down to form an annular groove, and an open locking ring is sleeved in the annular groove. When the upper joint is lifted, the second pin can be cut off to retract the rubber tube and unseal it.

Description

Technical Field

[0001] The invention belongs to the technical field of well plugging, and in particular relates to a thermal recovery packer with a rubber tube that is easy to expand and plug. Background Art

[0002] Thermal recovery packers are common and key downhole tools in heavy oil production. They are used for steam injection well plugging and stratified steam injection. Thermal recovery packers need to withstand high temperature and high pressure, and have high performance requirements. The more common Y241 packers currently use hydraulic setting and lifting to release the seal. When setting, the rubber cylinder is squeezed axially by external force. During the axial squeezing process, the rubber cylinder expands radially outward to achieve the purpose of plugging the annulus of the oil casing.

[0003] Among them, the Chinese utility model patent with the authorization announcement number CN215907813U adopts the method of axially extruding the rubber cylinder to make the rubber cylinder expand radially outward. Specifically, the patent discloses a packer with good sealing performance, including an upper joint, the lower part of which is threadedly connected with a center tube and a cylinder sleeve, the cylinder sleeve is located outside the center tube and is spaced from the center tube, a sliding seal is assembled with a push sleeve in the interval, the lower end of the center tube is threadedly connected with a lower joint, a positioning sleeve is installed on the outside of the lower joint through shear nails, a rubber cylinder is arranged between the cylinder sleeve and the positioning sleeve, and the rubber cylinder seats fixed by vulcanization at both ends of the rubber cylinder are engaged with the cylinder sleeve and the positioning sleeve. A liquid inlet hole connected to the internal channel of the center tube is opened on the upper joint, a one-way valve is arranged in the liquid inlet hole, and the top surface of the cylinder sleeve is connected to the one-way valve. When in use, the pressure liquid enters the top of the cylinder sleeve through the liquid inlet hole and the one-way valve, and the pressure liquid pushes the cylinder sleeve downward. The cylinder sleeve moving downward cooperates with the positioning sleeve to axially squeeze the rubber cylinder, forcing the rubber cylinder to expand radially outward and expand to seal. Under the action of the one-way valve, the rubber cylinder no longer shrinks and remains in an expanded and sealed state; when unsealing, the pipe column is rotated, the shear pins are cut off, and the positioning sleeve moves downward relative to the lower joint under the action of the rebound force of the rubber cylinder, and the unsealing is completed.

[0004] The packers in the prior art, whether Y241 packers or other types of packers, mostly adopt the method of axially squeezing the rubber tube to expand radially outward and expand to seal. However, the axial sealing force required for this expansion sealing method is relatively large, and it is not easy to seal. Moreover, the rubber tube is axially squeezed and expanded under the action of the sealing force. During this process, the rubber tube and the well wall will rub against each other, which may easily cause wear on the surface of the rubber tube, resulting in poor sealing of the packer and a low sealing success rate. Summary of the invention

[0005] The object of the present invention is to provide a thermal recovery packer to solve the technical problem in the prior art that radial outward expansion sealing is achieved by axially extruding a rubber cylinder, resulting in a large required sealing force and a low sealing success rate.

[0006] To achieve the above-mentioned purpose, the technical scheme of the thermal recovery packer provided by the present invention is: a thermal recovery packer, comprising an upper joint and a central tube and a lower joint connected to the upper joint in sequence, the upper joint is also connected to an outer tube, the central tube and the outer tube are arranged at intervals from the inside to the outside, the lower joint comprises a small hole section located at the bottom and connected to the central tube, and also comprises a large hole section located at the top, the large hole section of the lower joint and the central tube form an annular piston cavity with an opening at the top and a closed bottom, an annular piston is installed in the annular piston cavity in a sliding seal along the up and down directions, the upper end of the annular piston extends into the outer tube and is connected to the outer tube through a first pin, A connecting hole is provided on the wall of the center tube, which is connected to the annular piston cavity and is located below the annular piston. The connecting hole is used to inject liquid into the annular piston cavity to push the annular piston upward. When the thrust reaches the design value, the first pin is sheared off and the annular piston is pushed upward. A rubber sleeve is sleeved on the outside of the annular piston above the lower joint. The upper end of the rubber sleeve is fixedly connected or press-fitted with the bottom of the outer tube. The annular piston has a conical support section for supporting the bottom of the rubber sleeve. The outer diameter of the conical support section gradually increases from top to bottom. When the annular piston is pushed upward, the conical support section is inserted into the rubber sleeve and the rubber sleeve is radially expanded outward to seal the oil casing annulus.

[0007] The annular piston comprises a small hole section located at the bottom and slidingly sealingly matched with the center tube and a large hole section at the top. The inner diameter of the large hole section of the annular piston is larger than the outer diameter of the center tube. A locking buckle is provided on the inner wall of the large hole section of the annular piston. A locking ring seat is correspondingly provided on the outer wall of the center tube. An unsealing ring is installed on the locking ring seat through a second pin. The locking ring seat has a downward annular step. The annular step and the unsealing ring are spaced up and down to form an annular groove. An open locking ring is set in the annular groove. The open locking ring is provided with locking teeth. When the annular piston moves upward, the locking buckle passes over the locking teeth and is unidirectionally locked by the locking teeth to prevent it from moving downward relative to the open locking ring. When the upper joint is lifted, the second pin can be cut off so that the unsealing ring and the open locking ring move downward with the annular piston to retract and unseal the rubber cylinder. The thermal recovery packer comprises a sleeve on the outside of the annular piston. An upper shoulder guard and a lower shoulder guard are arranged on the upper and lower sides of the rubber cylinder, the upper shoulder guard is used to be pressed by the rubber cylinder and the outer tube to expand radially outward when the rubber cylinder is sealed, an outer pressure ring is fixed to the outside of the annular piston, the outer pressure ring is used to move up with the annular piston and press the lower shoulder guard when the rubber cylinder is sealed, and the lower shoulder guard is compressed by the rubber cylinder and the outer pressure ring to expand radially outward when the rubber cylinder is sealed, the rubber cylinder is a modified polytetrafluoroethylene rubber cylinder, the upper shoulder guard and the lower shoulder guard are both graphite wire mesh, the thermal recovery packer also includes a rubber cylinder retaining ring located below the lower shoulder guard, the outer pressure ring pushes the lower shoulder guard by pushing the rubber cylinder retaining ring, an outer annular step facing upward is provided on the outer periphery of the annular piston, an outer sealing gasket is supported and placed on the outer annular step, the outer pressure ring is threadedly assembled on the annular piston and presses the outer sealing gasket downward onto the outer annular step.

[0008] Beneficial effects: In the present invention, the tapered section of the annular piston can be inserted into the rubber cylinder when it moves upward to make the rubber cylinder expand radially outward, thereby achieving sealing. Compared with the method of forcing the rubber cylinder to expand radially outward by axial extrusion in the prior art, the required sealing force is smaller; during the sealing process, the rubber cylinder only expands radially outward and does not rub against the well wall, thereby avoiding wear, thereby solving the technical problems of the prior art sealing method that the sealing force required is large and easy to wear. The present invention prevents the rubber cylinder from returning to its original position after being sealed by means of a lock buckle and an open lock ring, and realizes unsealing by means of a second pin, and the first pin ensures that the thermal recovery packer will not be sealed prematurely due to excessive liquid pressure in the well after being lowered into the well along with the pipe string; the upper shoulder guard and the lower shoulder guard are both graphite wire protective nets, which are prone to radial expansion after being subjected to axial force, and by providing the upper shoulder guard and the lower shoulder guard, the upper and lower ends of the rubber cylinder can be stopped and positioned after the rubber cylinder is sealed, so as to prevent the rubber cylinder from softening during high-temperature steam injection and then leaking from the gap between the thermal recovery packer and the well wall; after the rubber cylinder retaining ring is provided, the outer pressure ring will not directly contact the lower shoulder guard, so as to protect the lower shoulder guard; the sealing between the annular piston and the inner wall of the lower joint is realized by the cooperation of the outer annular step, the outer pressure ring and the outer sealing gasket, and the outer pressure ring plays the role of both pushing the lower shoulder guard and pressing the outer sealing gasket, so that the functions are more concentrated and the required parts are fewer.

[0009] Furthermore, at least one of the bottom surface of the open lock ring and the top surface of the unsealing ring is an inclined surface, and the inclined surface extends from top to bottom and radially outward. After the open lock ring is matched with the lock buckle, the annular piston where the lock buckle is located is subjected to a downward force under the action of its own weight and the retraction of the rubber cylinder, and the lock buckle will be supported on the unsealing ring. After the inclined surface is set, the greater the force applied to the annular piston, the larger the outer expansion size of the open lock ring, and the more reliable the matching between the locking teeth on the open lock ring and the lock buckle, thereby preventing the annular piston from descending to unseal.

[0010] Furthermore, the inner circumference of the annular piston is provided with an inner annular step facing downward, the inner circumference of the annular piston is threadedly equipped with an inner pressure ring, an inner sealing gasket is provided between the inner pressure ring and the inner annular step, and the inner pressure ring is used to press the inner sealing gasket against the inner annular step. The sealing performance between the annular piston and the center tube is ensured by providing the inner annular step, the inner pressure ring and the inner sealing gasket.

[0011] Furthermore, the outer sealing gasket and the inner sealing gasket each include at least two graphite rings stacked together. The graphite rings are resistant to high temperature and high pressure and are suitable for use in high-temperature steam injection thermal recovery.

[0012] Furthermore, the outer tube is provided with a flow hole, which is connected to the upper end surface of the annular piston through the annular space between the outer tube and the center tube. When the well is lowered, the liquid in the well will not only enter the annular piston cavity through the communication hole and push the annular piston upward, but also enter the top of the annular piston through the flow hole and push the annular piston downward, ensuring that the annular piston will not shear the first pin due to being pushed, thereby avoiding premature setting.

[0013] Furthermore, at least two of the first pins and the second pins are evenly distributed along the circumference. At least two of the first pins and the second pins are evenly distributed along the circumference, which can ensure balanced force in all directions.

[0014] Furthermore, at least two communicating holes are arranged along the circumferential direction. Providing at least two communicating holes can increase the thrust force on the annular piston during hydraulic setting, thereby improving the setting efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic structural diagram of the thermal recovery packer provided by the present invention;

[0016] Figure 2 for Figure 1 The enlarged view of point A in the middle;

[0017] Figure 3 for Figure 1 The enlarged view of point B in the middle;

[0018] Description of reference numerals:

[0019] 1. Upper joint; 2. Outer tube; 3. Flow hole; 4. Center tube; 5. Lock ring seat; 6. First pin; 7. Open lock ring; 8. Upper shoulder guard; 9. Second pin; 10. Unsealing ring; 11. Rubber cylinder; 12. Lock buckle; 13. Lower shoulder guard; 14. Rubber cylinder retaining ring; 15. Annular piston; 16. First sealing ring; 17. Outer pressure ring; 18. Outer sealing gasket; 19. Inner sealing gasket; 20. Inner pressure ring; 21. Second sealing ring; 22. Annular piston chamber; 23. Lower joint; 24. Connecting hole; 25. First annular space; 26. Second annular space; 27. Inclined surface. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention, that is, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. The components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0021] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present invention.

[0022] It should be noted that relational terms such as "first" and "second" that may appear are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, terms such as "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device that includes a series of elements includes not only those elements, but also other elements that are not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, elements defined by the sentence "including a...", etc., do not exclude the process or method that includes the elements.

[0023] In the description of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" that may appear should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0024] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the term "provided with" that may appear should be understood in a broad sense. For example, the object "provided with" may be a part of the body, or may be arranged separately from the body and connected to the body, and the connection may be a detachable connection or an inseparable connection. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0025] The present invention is further described in detail below in conjunction with embodiments.

[0026] Specific embodiments of the thermal recovery packer provided by the present invention:

[0027] like Figures 1 to 3As shown, the thermal recovery packer is applied to the working condition of stratified steam injection thermal recovery, including an upper joint 1, which has inner buckles on the upper and lower parts and outer buckles on the outer side. The inner buckle at the upper end of the upper joint 1 is used to connect with the oil pipe, and the center pipe 4 is installed in the inner buckle at the lower end. The center pipe 4 extends downward, and the outer buckle of the upper joint 1 is installed with an outer pipe 2. The outer pipe 2 includes a small hole section at the top and a large hole section at the bottom. The small hole section of the outer pipe 2 is threadedly assembled on the upper joint 1, and the inner diameter of the large hole section at the bottom is larger than the outer diameter of the center pipe 4 and the upper joint 1, so as to form a second annular space 26 with a closed top and an open bottom. The upper and lower parts of the outer pipe 2 are respectively provided with four through holes evenly distributed along the circumference. The four through holes at the upper part are flow holes 3, and the flow holes 3 are used for liquid to enter the second annular space 26; the four through holes at the lower part are used for the first pin 6 to penetrate.

[0028] The lower end of the central tube 4 is connected to a lower joint 23, which includes a large hole section at the top and a small hole section at the bottom. The central tube 4 and the small hole section of the lower joint 23 are threaded together, and an annular piston cavity 22 with an open top and a closed bottom is formed between the large hole section of the lower joint 23 and the central tube 4. Four circumferentially evenly distributed communication holes 24 are opened at the lower part of the central tube 4, and the communication holes 24 connect the annular piston cavity 22 and the inner cavity of the central tube 4. Figure 1 As shown, there is no contact between the outer tube 2 and the lower joint 23.

[0029] An annular piston 15 is installed in a sliding seal in the annular piston cavity 22. The top of the annular piston 15 extends into the outer tube 2, and the bottom is located above the connecting hole 24. Two annular grooves are provided on the inner and outer circumferential surfaces of the annular piston 15. A first sealing ring 16 is installed in the annular groove of the inner circumferential surface, and a second sealing ring 21 is installed in the annular groove of the outer circumferential surface. The first sealing ring 16 seals the gap between the annular piston 15 and the center tube 4, and the second sealing ring 21 seals the gap between the annular piston 15 and the lower joint 23. The first sealing ring 16 is located above the second sealing ring 21, and the first sealing ring 16 and the second sealing ring 21 are made of high temperature resistant fluororubber material.

[0030] An outer annular step facing upward is provided on the outer circumference of the annular piston 15, and an outer sealing gasket 18 is supported on the outer annular step. The outer sealing gasket 18 adopts a graphite ring resistant to high temperature and high pressure, and multiple graphite rings are stacked in the up-down direction. An outer pressure ring 17 is also threadedly mounted on the outer circumference of the annular piston 15, and the outer pressure ring 17 presses the outer sealing gasket 18 against the outer annular step, thereby sealing the annular piston 15 and the lower joint 23. Similarly, an inner annular step facing downward is provided on the inner circumference of the annular piston 15, and an inner pressure ring 20 is also threadedly mounted on the inner circumference. An inner sealing gasket 19 is pressed between the inner pressure ring 20 and the inner annular step. The inner sealing gasket 19 also adopts multiple graphite rings resistant to high temperature and high pressure, and the inner sealing gasket 19 serves as a seal between the annular piston 15 and the center tube 4.

[0031] like Figure 1 As shown, the outer part of the annular piston 15 is covered with an upper shoulder guard 8, a rubber cylinder 11, a lower shoulder guard 13 and a rubber cylinder retaining ring 14 in order from top to bottom, and there is no connection between the components. The rubber cylinder 11 adopts a modified polytetrafluoroethylene rubber cylinder resistant to high temperature and high pressure, and the upper shoulder guard 8 and the lower shoulder guard 13 adopt a graphite steel wire protective net with a large elastic deformation. After the elastic deformation, it can prevent the rubber cylinder 11 from deforming and losing due to failure to reliably stop the deformation during high-temperature steam injection.

[0032] The outer diameter of the annular piston 15 is small at the top and large at the bottom. There is a tapered section at the intersection, whose outer diameter gradually increases from top to bottom. The bottom inner side of the rubber cylinder 11 is consistent with the tapered section of the annular piston 15, and it is supported on the tapered section of the annular piston 15. When the annular piston 15 moves upward, the tapered section can generate radial force, driving the rubber cylinder 11 to expand and deform radially, thereby sealing the oil casing annulus. In order to keep the rubber cylinder 11 in the expanded and deformed state after expansion and deformation, as shown in FIG. Figure 1 and Figure 2 As shown, the inner diameter of the annular piston 15 is designed to be larger at the top and smaller at the bottom, a first annular space 25 is formed between the larger large hole section at the top and the center tube 4, and the smaller small hole section at the bottom is in sliding sealing cooperation with the center tube 4. A lock buckle 12 is provided on the inner circumferential surface of the large hole section of the annular piston 15, and the lock buckle 12 extends a certain length in the up and down directions. A lock ring seat 5 is assembled on the external thread of the center tube 4. The lock ring seat 5 is a structure with an outer diameter larger at the top and smaller at the bottom, forming a downward annular step. A groove is provided on the small diameter section of the lock ring seat 5, and an unsealing ring 10 is sleeved on the bottom of the lock ring seat 5. The unsealing ring 10 has 8 threaded holes evenly distributed along the circumferential direction, and the threaded holes correspond one by one to the grooves on the lock ring seat 5, and the unsealing ring 10 is installed on the lock ring seat 5 by a second pin 9. An open locking ring 7 is sleeved in the annular groove between the unsealing ring 10 and the large diameter section of the locking ring seat 5. The open locking ring 7 is constrained in the annular groove. The open locking ring 7 is a locking ring with an opening on one side. It has the ability of elastic contraction and expansion. Locking teeth are provided on the outer periphery of the open locking ring 7. The locking teeth are arranged tilted upward. The locking teeth and the locking buckle 12 are in a one-way locking relationship. The locking buckle 12 can move upward relative to the locking teeth. After passing the locking teeth, the locking teeth lock the locking buckle 12 to prevent the annular piston 15 where the locking buckle 12 is located from descending.

[0033] like Figure 2 As shown, the bottom of the open locking ring 7 and the bottom of the unsealing ring 10 are both provided with a bevel 27, and the bevel 27 extends radially from the inside to the outside and tilts outward. The open locking ring 7 and the unsealing ring 10 are both provided with the bevel 27. The purpose is that when the open locking ring 7 is locked with the lock buckle 12, the open locking ring 7 is pulled down by the deadweight of the annular piston 15 where the lock buckle 12 is located, and the bevel 27 can keep the open locking ring 7 in an expanded state, thereby ensuring that the locking teeth of the open locking ring 7 and the lock buckle 12 are always kept locked.

[0034] like Figure 1As shown, the upper end of the annular piston 15 extends into the outer tube 2, and four evenly distributed threaded holes are opened on the upper end of the annular piston 15. The first pin 6 passes through the through hole at the bottom of the outer tube 2 and cooperates with the threaded hole to fix the annular piston 15 on the outer tube 2.

[0035] After all the components are assembled, the upper shoulder guard 8 is pressed against the bottom of the outer tube 2 .

[0036] The use process of the present invention is as follows: the thermal recovery packer is lowered into the well with the pipe string to the designed depth, and the oil pipe is used to drop a ball to pressurize it. The hydraulic pressure enters the annular piston cavity 22 through the four connecting holes 24 at the bottom of the central pipe 4, generating an upward thrust. When a certain pressure is reached, the first pin 6 is sheared off, pushing the annular piston 15 upward, and the first sealing ring 16, the outer pressure ring 17, the outer sealing pad 18, the inner sealing pad 19, the inner pressure ring 20, and the second sealing ring 21 move upward with the annular piston 15 at the same time. Under the action of the thrust, the conical section of the annular piston 15 generates a radial force, causing the rubber cylinder 11 to expand and deform radially, and at the same time, the locking pressure on the open locking ring 7 is locked with the locking buckle 12 of the annular piston 15, so that the annular piston 15 is fixed, and the packer is set. When the packer is set, the outer pressure ring 17 pushes the rubber tube retaining ring 14 and the lower shoulder guard 13 and presses on the rubber tube 11. The upper shoulder guard 8 and the lower shoulder guard 13 are elastically deformed and expanded outward to block the upper and lower ends of the rubber tube 11 to prevent the rubber tube 11 from being lost.

[0037] When unsealing, the pipe column is lifted, and the lifting force is transmitted to the central pipe 4 through the upper joint 1, and then to the lock ring seat 5 by the central pipe 4, and then to the second pin 9 by the lock ring seat 5. Since the rubber cylinder 11 is tightened in the casing at this time, the rubber cylinder 11 and the parts connected to the rubber cylinder 11 cannot move. When the lifting force of the pipe column is greater than the shear force of the second pin 9, the second pin 9 is sheared off, and the open lock ring 7 is no longer constrained by the lock ring seat 5. Under the elastic restoring force of the rubber cylinder 11, the annular piston 15, the open lock ring 7 and the lock ring seat 5 all move downward, and the rubber cylinder 11 is separated from the casing, completing the unsealing process.

[0038] Among them, the role of the first pin 6 is to prevent the annular piston 15 from moving upward due to the force of the downhole liquid during the downhole process, causing the seal to be sealed prematurely; and, by opening the flow hole 3 on the outer tube 2, the liquid can be led to the upper end of the annular piston 15, exerting a certain downward force on the annular piston 15, forming a balance with the upward force exerted by the liquid on the annular piston 15.

[0039] It should be noted that the thermal recovery packer of the present invention does not have an anchoring structure such as slips, and needs to be connected to the anchoring structure when in use. The anchoring structure also adopts a lifting and unsealing method.

[0040] In this embodiment, there are four communicating holes 24 evenly distributed along the circumferential direction. In other embodiments, the number of communicating holes 24 can be increased or decreased according to the required flow rate, and can also be one. In addition, the arrangement of the communicating holes 24 is not limited to even distribution.

[0041] In this embodiment, there are 4 first pins 6 evenly distributed in the circumferential direction, and there are 8 second pins 9 evenly distributed in the circumferential direction. In other embodiments, the number and arrangement of the first pins 6 and the second pins 9 are changed according to actual conditions.

[0042] In this embodiment, the outer tube 2 is provided with a through hole 3. In other embodiments, the outer tube is no longer provided with a through hole. To prevent premature setting, the diameter of the first pin can be increased to increase the force required for shearing.

[0043] In this embodiment, the outer sealing gasket 18 and the inner sealing gasket 19 each include at least two graphite rings stacked together. In other embodiments, the outer sealing gasket 18 and the inner sealing gasket 19 may be ordinary rubber gaskets.

[0044] In this embodiment, the inner periphery of the annular piston 15 is sealed with the central tube 4 through the inner pressure ring 20, the inner sealing gasket 19 and the first sealing ring 16, and the outer periphery is sealed with the lower joint 23 through the outer pressure ring 17, the outer sealing gasket 18 and the second sealing ring 21. In other embodiments, only the first sealing ring 16 and the second sealing ring 21 are retained. In this case, the outer pressure ring 17 only plays the role of pushing the lower shoulder guard 13.

[0045] In this embodiment, there is a rubber sleeve retaining ring 14 below the lower shoulder guard 13. In other embodiments, the rubber sleeve retaining ring 14 is cancelled, and the lower shoulder guard 13 is directly pushed by the outer pressure ring 17.

[0046] In this embodiment, the rubber cylinder 11 is protected by providing an upper shoulder guard 8 and a lower shoulder guard 13. In other embodiments, if only for the convenience of setting, the upper shoulder guard 8 and the lower shoulder guard 13 are cancelled.

[0047] In this embodiment, there is only a press fit relationship between the upper end of the rubber sleeve 11 and the outer tube 2, but no fixed connection relationship. In other embodiments, the rubber sleeve 11 is fixedly connected to the outer tube 2. Of course, if there is an upper shoulder guard 8, the rubber sleeve 11, the upper shoulder guard 8 and the outer tube 2 can be fixed together.

[0048] In this embodiment, the bottom surface of the open locking ring 7 and the top surface of the unsealing ring 10 are both inclined surfaces. In other embodiments, only one of the two is an inclined surface; in other embodiments, neither is an inclined surface, that is, the bottom surface of the open locking ring 7 and the top surface of the unsealing ring 10 are both planes, and the unsealing ring 10 supports the open locking ring 7 through the plane.

[0049] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention is described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions recorded in the aforementioned embodiments without creative work, or replace some of the technical features therein with equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims

1. A thermal recovery packer, comprising an upper joint, a central pipe and a lower joint connected to the upper joint in sequence, characterized in that: The upper joint is also connected to an outer tube, and the center tube and the outer tube are arranged at intervals from the inside to the outside. The lower joint includes a small hole section located below and connected to the center tube, and also includes a large hole section located above. The large hole section of the lower joint and the center tube form an annular piston chamber with an open top and a closed bottom. An annular piston is installed in the annular piston chamber in a sliding and sealing manner along the up and down directions. The upper end of the annular piston extends into the outer tube and is connected to the outer tube through a first pin. A connecting hole connected to the annular piston chamber and located below the annular piston is provided on the tube wall of the center tube. The connecting hole is used to inject liquid into the annular piston chamber to push the annular piston upward. When the thrust reaches the design value, the first pin is cut off and the annular piston is pushed up. A rubber sleeve is sleeved on the outside of the annular piston above the lower joint. The upper end of the rubber sleeve is fixedly connected to the bottom of the outer tube or press-fitted. The annular piston has a conical support section for supporting the bottom of the rubber sleeve. The outer diameter of the conical support section gradually increases from top to bottom. When the annular piston is pushed upward, the conical support section is inserted into the rubber sleeve and the rubber sleeve is radially expanded outward to seal the oil casing annulus. The annular piston comprises a small hole section located at the bottom and slidingly sealingly matched with the center tube and a large hole section at the top. The inner diameter of the large hole section of the annular piston is larger than the outer diameter of the center tube. A locking buckle is provided on the inner wall of the large hole section of the annular piston. A locking ring seat is correspondingly provided on the outer wall of the center tube. An unsealing ring is installed on the locking ring seat through a second pin. The locking ring seat has a downward annular step. The annular step and the unsealing ring are spaced up and down to form an annular groove. An open locking ring is set in the annular groove. The open locking ring is provided with locking teeth. When the annular piston moves upward, the locking buckle passes over the locking teeth and is unidirectionally locked by the locking teeth to prevent it from moving downward relative to the open locking ring. When the upper joint is lifted, the second pin can be cut off so that the unsealing ring and the open locking ring move downward with the annular piston to retract and unseal the rubber cylinder. The thermal recovery packer comprises a sleeve on the outside of the annular piston. An upper shoulder guard and a lower shoulder guard are arranged on the upper and lower sides of the rubber cylinder, the upper shoulder guard is used to be pressed by the rubber cylinder and the outer tube to expand radially outward when the rubber cylinder is sealed, an outer pressure ring is fixed to the outside of the annular piston, the outer pressure ring is used to move up with the annular piston and press the lower shoulder guard when the rubber cylinder is sealed, and the lower shoulder guard is compressed by the rubber cylinder and the outer pressure ring to expand radially outward when the rubber cylinder is sealed, the rubber cylinder is a modified polytetrafluoroethylene rubber cylinder, the upper shoulder guard and the lower shoulder guard are both graphite wire mesh, the thermal recovery packer also includes a rubber cylinder retaining ring located below the lower shoulder guard, the outer pressure ring pushes the lower shoulder guard by pushing the rubber cylinder retaining ring, an outer annular step facing upward is provided on the outer periphery of the annular piston, an outer sealing gasket is supported and placed on the outer annular step, the outer pressure ring is threadedly assembled on the annular piston and presses the outer sealing gasket downward onto the outer annular step.

2. The thermal recovery packer according to claim 1, characterized in that: At least one of the bottom surface of the open lock ring and the top surface of the unsealing ring is an inclined surface, and the inclined surface extends obliquely from top to bottom and radially outward.

3. The thermal recovery packer according to claim 1, characterized in that: The inner circumference of the annular piston is provided with an inner annular step facing downwards, the inner circumference of the annular piston is threadedly equipped with an inner pressure ring, an inner sealing gasket is provided between the inner pressure ring and the inner annular step, and the inner pressure ring is used to press the inner sealing gasket against the inner annular step.

4. The thermal recovery packer according to claim 3, characterized in that: The outer sealing gasket and the inner sealing gasket each include at least two graphite rings stacked together.

5. The thermal recovery packer according to claim 1 or 2, characterized in that: The outer tube is provided with a flow hole, and the flow hole is communicated with the upper end surface of the annular piston through the annular space between the outer tube and the central tube.

6. The thermal recovery packer according to claim 1 or 2, characterized in that: There are at least two of the first pins and the second pins evenly distributed along the circumferential direction.

7. The thermal recovery packer according to claim 1 or 2, characterized in that: At least two communicating holes are arranged along the circumferential direction.

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