A downhole packer

Abstract

The application is a downhole packer, which comprises a setting mechanism and a releasing mechanism, and the locking mechanism is provided with an upper central pipe and a back-inserted pipe string connecting ring; the inner circle of the upper joint is sequentially connected with the upper central pipe and the lower central pipe and the releasing cylinder which can be inserted into the production pipe string from top to bottom; the outer surface of the upper central pipe and the lower central pipe is sequentially connected with the locking mechanism, the setting mechanism provided with a sealing assembly and the releasing mechanism through the upper connecting cylinder, the lower connecting cylinder, the lower top cylinder, the connecting head transmission torque cylinder and the lower joint from top to bottom; the transmission torque cylinder in the releasing mechanism is installed between the lower central pipe and the releasing cylinder and is provided with a ratchet pawl; the releasing cylinder is connected with the lower central pipe through a shear pin; the upper joint can be connected with the running-in pipe string through the shear pin; and the back-inserted pipe string connecting ring can be connected with the inserted pipe connected with the lower end of the production pipe string. The upper wellbore operation is facilitated without releasing and pulling out the packer, and the maintenance period and cost and the service life of the application well operation are significantly reduced and prolonged.

Description

Technical Field

[0001] This invention relates to packers used in oil wells in the petroleum industry, specifically a downhole packer. Background Technology

[0002] Packers are key tools used in production tubing for oil, gas, and water wells in the petroleum industry. Their main purpose is to isolate and seal the annular space between the production tubing and the casing of the oil layer. While protecting the upper casing from high injection pressure, they can also protect the upper casing from corrosion by the injected gas, thus extending the service life of oil, gas, and water wells.

[0003] Currently, the retrievable Y445 packer used in oil, gas, and water wells can only withstand unidirectional high pressure. Its sealing pressure is low, and it only protects the upper casing from corrosion by injected gas. When run into the well, it is connected to the downhole tubing and is lowered into the well in one go. Whenever a wellbore problem occurs requiring work, regardless of the depth, the entire downhole tubing must be retrieved. This not only results in long construction periods and high costs but also necessitates well control operations, posing significant safety hazards and damaging the oil reservoir. For example, the following packer: The bidirectional compression hydraulic setting packer without anchoring, as described in patent application CN201610803778.5, used in CCUS injection-production wells, has been found to be prone to creep and seal failure in actual use, according to field application. Therefore, in practical applications, packers with anchoring function have been gradually adopted to extend the effective working life of the packer and prevent the problem of pressure in the annulus caused by packer creep.

[0004] The bidirectional pressure-bearing compression hydraulic packer disclosed in patent application CN201410383091.1 and the article "Development of a Bidirectional Three-Force Loading Gas Injection Packer" discusses a bidirectional pressure-bearing compression hydraulic packer. This packer adopts a double-cylinder structure, where the rubber sleeve is fully compressed by bidirectional hydraulic pressure and external load, resulting in a more uniform axial stress distribution with the casing and significantly improving the sealing effect of the rubber sleeve. By adding a tightening mechanism, it compensates for the return of the locking ring after the hydraulic pressure disappears and the slight settling distance generated by continuous compression of the rubber sleeve, solving the problem of insufficient pressure-bearing capacity of the gas injection packer and structurally ensuring the long-term sealing performance of the packer. This bidirectional three-force loading gas injection packer has been field-applied in CO2-driven oilfields, with a maximum gas injection pressure of 28 MPa, meeting the gas injection technology requirements for packer airtightness. However, with the expansion of CO2 flooding applications and the improvement of process parameters, some injection wells require operations on the upper casing of the packer. The packer has also revealed problems such as low pressure bearing capacity and inconvenience for upper casing operations.

[0005] To address these issues in field applications, a tubing-type packer has been introduced. The tubing packer discussed in patent application CN201310229900.9 ("A Tubing Packer") and the article "Design and Development of an Insertion-Type High-Temperature and High-Pressure Gas Injection Packer" features an integral sealing tubing design, reducing connection points and mitigating leakage risk. It also incorporates a sealing ring that is integrally vulcanized with the tubing body, preventing damage to the sealing ring due to tubing creep and improving the sealing effect and lifespan. Furthermore, it utilizes a gas-tight rubber sleeve with a segmented, openable rigid support design to prevent sleeve damage and enhance gas injection sealing performance. While this packer effectively solves the problem of inconvenient upper wellbore operations, its single-unit packer sleeve exhibits uneven bidirectional pressure resistance in practical field applications, with high upper pressure resistance but low lower pressure resistance, hindering future increases in injection pressure levels.

[0006] In summary, there is an urgent need in the field for a downhole packer that can withstand high pressure in both directions, facilitate subsequent upper wellbore operations, and has a long service life and low maintenance cost to solve the above problems. Summary of the Invention

[0007] To address the aforementioned problems, this invention provides a downhole packer that solves the issues of low packing pressure and inconvenience for subsequent upper wellbore operations in existing gas injection packers. This improves the service life of the gas injection packer, facilitates subsequent construction operations in the upper wellbore, thereby increasing the efficiency of well operations and reducing production costs.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: A downhole packer includes a setting mechanism and a releasing mechanism, wherein: The locking mechanism is equipped with an upper central tube and a return insertion post connecting ring; The inner circle of the upper connector is connected from top to bottom to the upper central tube, the lower central tube, and the unsealing cylinder, which are inserted into the production tubing. The upper and lower center tubes are connected from top to bottom to a locking mechanism, a sealing mechanism with sealing components, and an unsealing mechanism, which are connected by an upper connecting cylinder, a lower connecting cylinder, a lower top cylinder, a connecting head torque transmission cylinder, and a lower connector. The sealing assembly includes a main rubber sleeve and an auxiliary rubber sleeve installed on the outside of the upper and lower cones on both sides of the slip. The two sides of the slip are connected to the upper and lower cones by keyways. The upper connecting sleeve is connected to the upper cone and the lower connecting sleeve is connected to the lower top sleeve by shear pins. A pawl-equipped shearing cylinder is installed between the torque transmission cylinder and the lower central tube and the unsealing cylinder in the unsealing mechanism. The unsealing cylinder and the lower central tube are connected by shear pins. The upper connector can be connected to the feed string via shear pins; The insertion tube connection ring can be connected to the insertion tube at the lower end of the production tube.

[0009] Preferably, the locking mechanism further comprises a locking ring, a locking upper cylinder, a locking lower cylinder, and a return insertion column connecting ring. The locking upper cylinder, which is connected to the locking ring, is sequentially threaded to the locking lower cylinder and the upper connecting cylinder. The locking upper cylinder is connected to the upper central tube by a shear pin, and the locking ring is installed in the annular space formed by the upper central tube, the locking upper cylinder, and the locking lower cylinder. The return insertion column connecting ring is installed in the gap after the upper central tube and the lower central tube are threaded together, and the insertion protrusion at the lower end is placed in the insertion groove in the upper inner circle of the lower central tube, limiting the insertion of the lower end of the production column inserted into the upper central tube. The inner circle of the upper central tube is a precision-machined sealing surface.

[0010] Preferably, the internal threads of the locking ring and the internal threads of the return insertion tube connecting ring are both toothed threads and are respectively matched with the toothed threads of the outer circle of the upper central tube and the outer circle of the lower end insertion tube of the production tube; the locking ring and the return insertion tube connecting ring are both provided with a broken ring structure that penetrates the ring body and are respectively provided with an oblique broken groove one and an axial broken groove two in the ring body.

[0011] Preferably, the lower central tube is a non-uniform diameter cylindrical body, with both the upper outer circle and the upper inner circle being larger than the lower outer circle and the lower inner circle. At least one sealing ring groove is provided in the upper inner circle of the lower central tube, and an internal thread connecting to the upper central tube is machined in the inner circle above the sealing ring groove. An insertion groove is machined on the upper end face of the lower inner circle of the lower central tube, matching the number and structure of the insertion protrusions in the insertion thread connecting ring, allowing the insertion protrusions to be inserted into the insertion groove. The lower end of the lower outer circle of the lower central tube is provided with an external thread capable of connecting to the shear cylinder, and at least one external thread is provided in the tube body above the external thread. one One screw hole.

[0012] Preferably, the sealing assembly installed outside the upper cone further includes an upper retaining ring, a spacer ring, and a lower retaining ring. A spacer ring is installed between the main rubber sleeves. Two upper retaining rings are installed outside the auxiliary pressure step of the auxiliary rubber sleeve. Two lower retaining rings are installed between the main rubber sleeve and the auxiliary rubber sleeve. The outer circumference of the auxiliary rubber sleeve has at least [missing information - likely a number or designation]. one A secondary pressure step; the sealing assembly outside the upper cone is installed between the lower end of the upper connecting cylinder and the outer circular step of the upper cone.

[0013] Preferably, the structure of the sealing assembly installed outside the lower cone is the same as that of the sealing assembly installed outside the upper cone; the center hole of the lower body of the upper top cylinder installed outside the lower cone matches the upper outer circle of the lower connecting cylinder, and the lower body of the upper top cylinder can sit on the step formed by the upper outer circle and the middle outer circle of the lower connecting cylinder; a disc spring is installed in the annular space formed by the upper top cylinder, the lower cone, and the lower connecting cylinder, and the disc spring is located at the lower end of the lower cone; the outer circle of the lower connecting cylinder is threaded to the lower cone and a sealing ring groove is provided at the lower end, and the sealing assembly outside the lower cone is placed together with the lower cone by the disc spring and the upper top cylinder.

[0014] Preferably, the slip is an arc-shaped block with anchor teeth machined on its outer wall. A V-shaped anti-deformation groove is machined axially in the anchor teeth, and a retractable ring mounting groove is machined circumferentially in the middle position of the anchor teeth. Conical surfaces are machined facing each other at both ends of the inner arc surface of the slip, and dovetail-shaped mating grooves are machined on the conical surfaces. At least two slips are installed outside the lower central tube. A retractable ring is installed in the retractable ring mounting groove. The retractable ring is a disconnectable ring with a stepped disconnectable groove machined axially in the ring body.

[0015] Preferably, the upper cone is a cylindrical body with a non-uniform outer diameter. A shearing groove is provided on the upper part of the outer circle of the upper cone, and a sealing ring groove is provided on the lower part of the inner circle. The lower outer circle has a conical structure. A protruding dovetail key is provided in the conical structure of the lower outer circle of the upper cone to mate with the mating groove in the slip. The protruding dovetail key is located on the lower push body at the lower part of the upper cone. The sealing assembly is installed on the outside of the upper outer circle of the upper cone.

[0016] Preferably, the lower cone is a cylindrical body with a non-uniform diameter, a sealing ring groove in its upper inner circle, and a conical structure in its upper outer circle; a protruding dovetail key strip is provided on the upper push body of the upper outer circle of the lower cone, which mates with the mating groove in the slip; the lower cylindrical body of the lower cone is located inside the upper top cylinder and is threadedly connected to the lower connecting cylinder; an adapter ring is also installed between the lower end of the upper top cylinder and the sealing assembly; a step is provided between the lower outer circle of the lower connecting cylinder and the upper inner circle of the lower top cylinder, and a shear pin groove is provided on the lower outer circle of the lower connecting cylinder, which can be fixed to the lower top cylinder by shear pins.

[0017] Preferably, the upper inner diameter of the connector is smaller than the lower outer diameter of the lower connecting cylinder, the torque transmission cylinder is a non-uniform diameter cylindrical body and the threads in the inner and outer circles at both ends can be connected to the connector and the lower connector respectively; the inner circle of the middle part of the torque transmission cylinder is provided with one or more spline grooves in the axial direction.

[0018] Preferably, the upper end of the inner circle of the unsealing cylinder is machined with an inner chamfer and has a sealing ring groove, a shear pin groove connected to the lower central tube, and a sitting step that mates with the inner circle step of the lower connector in the middle; the upper outer wall of the shear cylinder is machined with a number and structure of transmission splines that mate with the spline groove in the transmission cylinder, and an internal thread that connects to the lower connecting cylinder is machined in the inner circle above the inner circle step; one or more pawls are provided at the lower part of the shear cylinder body, and a pawl protrusion that mates with the inner circle step of the lower connector in the middle is provided on the lower outer wall of the pawl.

[0019] Preferably, the inner diameters of the insertion tubing connecting ring and the unsealing tube are both larger than the outer diameter of the downhole testing instrument.

[0020] Construction method for a downhole packer, comprising the following steps: A. First step: Run a downhole packer into the application well. a. Hydraulically set the downhole packer on the surface; b. After the packer is set, continue to increase the pressure, cut the shear pin connecting the upper connector and the feed tool, complete the release between the feed string and the packer, and remove the feed string and the feed tool. B. Second step, insert the production tubing string: Connect the tubing string to the bottom of the production tubing string, lower the production tubing string into the well and insert it into the upper center tube of the downhole packer.

[0021] Preferably, when the wellhead above the packer needs to be operated later, the production string is rotated back on the surface and the lower end of the insertion pipe is released from the back-insertion string connecting ring in the packer, so that the production string and the lower end of the insertion pipe can be retrieved.

[0022] Preferably, if the downhole packer needs to be retrieved in the later stages of use, a special retrieval string connected to the retrieval tool is lowered into the packer and the unsealing cylinder is pushed downwards. The retrieval tool is then connected to the re-insertion string connecting ring, and the upper center pipe, lower center pipe, and unsealing cylinder connected to the re-insertion string connecting ring are retrieved, thereby unsealing the downhole packer and retrieving all other components in the downhole packer from the well.

[0023] Compared with the prior art, the present invention has the following advantages: The upper and lower cones of this packer are both equipped with sealing components, forming a double sealing assembly. The pressure borne by the upper and lower ends of the sealing assembly is positive sealing, which can withstand a higher level of pressure compared with existing gas injection packers.

[0024] Compared with existing packers, the packer in this invention has a higher safety and reliability in terms of its unsealing mechanism and working principle. The outer diameter of the upper and lower sealing rings of the unsealing cylinder is equal, so the area of ​​hydraulic pressure borne by the upper and lower cross sections of the unsealing cylinder is equal. No matter how deep the initial insertion depth into the well is or how high the construction pressure is during later production, there will be no large pressure difference that would cause the shear pin to break prematurely, and there will be no premature unsealing.

[0025] The packer employs a selective setting method of suspension followed by setting. First, the packer is delivered to a predetermined position downhole via an insertion string, and then the setting tool within the string sets it for setting. The rubber sleeves in both sealing assemblies are provided with setting initiation force by pre-installed shear pins between the upper connecting cylinder and the upper cone, and between the lower connecting cylinder and the lower top cylinder. When the packer slips are engaged, all hydraulic pressure is used for slip anchoring until the hydraulic pressure reaches the setting initiation force of both seals. Only after the hydraulic pressure exceeds the setting initiation force of both seals does the packer's two seals begin to be pressurized and set. This suspension-following-setting principle allows for more stable packer anchoring and more complete rubber sleeve setting, resulting in a better and more significant setting effect compared to existing downhole packer setting mechanisms.

[0026] When used in application wells, this invention employs a two-step installation method: the first step is to run the packer into the well using an insertion string and set it. Drop The packer is then pulled out; the second step is to re-insert the production tubing. An insert seal is used between the packer and the production tubing to achieve an airtight seal. A locking mechanism and a release mechanism are also provided between them. When the lower end of the production tubing is inserted into the packer, sealing and locking are achieved. Later, when work is needed in the casing above the packer, simply rotate the upper re-inserted production tubing to the predetermined number of turns to release the tubing from the packer and pull out the production tubing. This process avoids the adverse consequences of having to remove the packer during its service life due to other constraints. It facilitates subsequent construction work in the wellbore above the packer, significantly reducing construction time and costs. It also significantly reduces safety hazards and environmental risks associated with production wells connected to existing packers during construction. Its effectiveness and the resulting economic and social benefits are significant.

[0027] In summary, this packer employs a dual-seal assembly, providing high sealing pressure and featuring a locking mechanism at the top. This facilitates upper wellbore operations without requiring unsealing or removal of the packer, significantly extending and reducing maintenance cycles and costs in later-stage well operations, thus prolonging the well's service life. Furthermore, the packer's large inner diameter allows for the passage of testing instruments, facilitating subsequent process testing and gas injection adjustments. This provides data and technical support for reservoir development adjustments, potentially further improving reservoir recovery.

[0028] This invention has significant effects and can achieve good economic and social benefits, and has great value for promotion and application. Attached Figure Description

[0029] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 This is a broken view of the overall structure of a downhole packer according to the present invention.

[0030] Figure 2 for Figure 1 A schematic diagram of the structure of the locking ring 3.

[0031] Figure 3 for Figure 1 A schematic diagram of the structure of the connecting ring 7 of the middle insertion column.

[0032] Figure 4 for Figure 1 A schematic diagram of the structure of the lower central tube 8.

[0033] Figure 5 for Figure 1 A schematic diagram of the structure of the auxiliary rubber sleeve 13.

[0034] Figure 6 for Figure 1 A schematic diagram of the upper cone 14.

[0035] Figure 7 for Figure 1 Structural schematic diagrams of the front view, left view, top view, and bottom view of the Zhongkawa 15.

[0036] Figure 8 for Figure 1 A schematic diagram of the structure of the shrinkable ring 16.

[0037] Figure 9 for Figure 1 A schematic diagram of the structure of the transmission torsion cylinder 24.

[0038] Figure 10 for Figure 1 A schematic diagram of the structure of the middle shear cylinder 26.

[0039] In the picture: Upper connector 1, upper center tube 2; Locking ring 3, broken groove 3-1; Locking upper cylinder 4, locking lower cylinder 5, upper connecting cylinder 6; 7. Insertion tube column connecting ring, 7-1 insertion protrusion, 7-2 break groove; Lower central tube 8, insertion groove 8-1; Upper protective ring 9, main rubber sleeve 10, spacer ring 11, lower protective ring 12; Auxiliary rubber cylinder 13, auxiliary pressure step 13-1; Upper cone 14: Lower thrust body 14-1; Kawa 15: Conical surface 15-1, mating groove 15-2, anchor tooth 15-3, anti-variation groove 15-4, shrinkable ring mounting groove 15-5; Shrinkable ring 16, disconnect groove 16-1; Lower cone 17, lower connecting cylinder 18, upper top cylinder 19, disc spring 20, adapter ring 21, lower top cylinder 22, connector 23; Torque cylinder 24, spline groove 24-1; Unsealing tube 25; 26-piece shear tube, 26-1-piece twist spline, 26-2-piece pawl, 26-3-piece pawl protrusion; Lower connector 27. Detailed Implementation

[0040] The accompanying drawings are for reference and illustration only and are not intended to limit the scope of protection of this invention. The technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0041] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0042] In the description of this invention, it should be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, in the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0043] See Figures 1-10 A downhole packer includes a setting mechanism and a releasing mechanism, wherein: The locking mechanism is equipped with an upper central tube 2 and a return insertion post connecting ring 7; The inner circle of the upper connector 1 is connected from top to bottom to the upper central tube 2, the lower central tube 8, and the unsealing cylinder 25, which are capable of being inserted into the production column. The upper central tube 2 and the lower central tube 8 are connected from top to bottom to a locking mechanism, a sealing mechanism equipped with sealing components, and an unsealing mechanism via an upper connecting cylinder 6, a lower connecting cylinder 18, a lower top cylinder 22, a connecting head 23, a torsion transmission cylinder 24, and a lower connector 27. The sealing assembly includes a main rubber sleeve 10 and an auxiliary rubber sleeve 13 installed on the outside of the upper cone 14 and lower cone 17 on both sides of the slip 15. The two sides of the slip 15 are connected to the upper cone 14 and lower cone 17 by keyways. The upper connecting sleeve 6 is connected to the upper cone 14 and the lower connecting sleeve 18 is connected to the lower top sleeve 22 by shear pins. When the packer is set and unsealed, the upper cone 14 and lower cone 17 can move relative to each other along the two conical surfaces of the slip 15. A pawl-equipped shear tube 26 is installed between the transmission cylinder 24 in the unsealing mechanism, the lower central tube 8, and the unsealing cylinder 25. The unsealing cylinder 25 is connected to the lower central tube 8 by a shear pin. During unsealing, the unsealing cylinder 25 can sit on the lower connector 27 to release the shear tube 26. The upper connector 1 can be connected to the feed string via shear pins; The insertion tube connection ring 7 can be connected to the insertion tube at the lower end of the production tube.

[0044] The sealing assembly of this invention includes a main rubber sleeve 10 and an auxiliary rubber sleeve 13, which are installed on the outside of the upper cone 14 and lower cone 17 on both sides of the slip 15. At the same time, the two sides of the slip 15 are connected to the upper cone 14 and lower cone 17 through keyways, ensuring that the sealing assembly installed on the outside of the upper cone 14 and lower cone 17 is in a positive sealing state when subjected to pressure. Both sets of sealing assemblies can move relative to each other along the two conical surfaces of the slip 15 under the drive of the upper cone 14 and lower cone 17, whether setting or unsealing, effectively improving the setting and unsealing reliability of this device and solving the problems of low sealing pressure and uneven pressure bearing capacity of existing downhole packers.

[0045] Since the upper central tube 2 and the insertion tube connecting ring 7 in the locking mechanism can cooperate and connect with the insertion tube connected to the lower end of the production tube inserted in the second step, the production tube can be sealed and locked. Therefore, normal production application can be achieved simply by inserting the insertion tube at the lower end of the production tube inserted in the second step into the locking mechanism of the present invention.

[0046] When it is necessary to inspect the wellbore above the packer later, simply rotate the production string that was lowered in the second step to the predetermined number of turns on the ground to release the packer from the lower end of the production string that was lowered in the second step.

[0047] If the packer needs to be removed for subsequent production layer changes, simply lower the special retrieval string into the packer, push down to open the unsealing cylinder 25, and then lift up the central tube 2 to unseal the packer and retrieve the invention.

[0048] This invention solves the problem of low sealing pressure in existing downhole packers, especially gas injection packers, and also addresses the issue that production wells using this packer must have their entire tubing string connected to the packer removed for subsequent construction work. This facilitates construction work in the production well and upper wellbore using this packer. Furthermore, because it eliminates the need to remove the packer from the well, it significantly extends the packer's lifespan, thereby substantially reducing subsequent operational costs, improving operational efficiency, protecting the environment, reducing the labor intensity of construction workers, and significantly lowering the overall production cost over the well's lifespan.

[0049] Based on the above embodiment one, the present invention also has the following embodiments: In a preferred embodiment, the locking mechanism further comprises a locking ring 3, a locking upper cylinder 4, a locking lower cylinder 5, and a return insertion tube connecting ring 7. The locking upper cylinder 4, connected to the locking ring 3, is sequentially threadedly connected to the locking lower cylinder 5 and the upper connecting cylinder 6. The locking upper cylinder 4 is connected to the upper central tube 2 via a shear pin, and the locking ring 3 is installed in the annular space formed by the upper central tube 2, the locking upper cylinder 4, and the locking lower cylinder 5. The return insertion tube connecting ring 7 is installed in the gap after the upper central tube 2 and the lower central tube 8 are threadedly connected, and the insertion protrusion 7-1 at its lower end is placed in the insertion groove 8-1 in the upper inner circle of the lower central tube 8, limiting the insertion of the lower end of the production tube inserted into the upper central tube 2. The inner circle of the upper central tube 2 is a precision-machined sealing surface, which can effectively seal and fit with the insertion tube. The insertion protrusion 7-1 engages with the insertion groove 8-1 in the lower central tube 8, which not only restricts the axial movement of the insertion tube connecting ring 7, but also restricts its rotation in the circumferential direction, thereby realizing the function of fixing and locking the tube after insertion at the lower end of the production tube and preventing it from being rotated and released.

[0050] In a preferred embodiment: the internal threads of the locking ring 3 and the internal threads of the return insertion tube connecting ring 7 are both toothed threads and are respectively matched with the toothed threads of the outer circle of the upper central tube 2 and the outer circle of the lower end insertion tube of the production tube; the locking ring 3 and the return insertion tube connecting ring 7 are both provided with a broken ring structure that penetrates the ring body and are respectively provided with an oblique broken groove 3-1 and an axial broken groove 7-2 in the ring body.

[0051] In a preferred embodiment: the lower central tube 8 is a non-uniform diameter cylindrical body, with its upper outer and inner circumferences both larger than its lower outer and inner circumferences. At least one sealing ring groove is provided in the upper inner circumference of the lower central tube 8, and an internal thread connecting to the upper central tube 2 is machined in the inner circumference above the sealing ring groove. Insertion grooves 8-1, matching the number and structure of the insertion protrusions 7-1 in the insertion tube column connecting ring 7, are machined on the upper end face of the lower inner circumference of the lower central tube 8, allowing the insertion protrusions 7-1 to be inserted into the insertion grooves 8-1. The lower end of the lower outer circumference of the lower central tube 8 is provided with an external thread capable of connecting to the shear cylinder 26, and at least one sealing ring groove is provided in the tube body above the external thread. one One screw hole.

[0052] In a preferred embodiment: the sealing assembly installed outside the upper cone 14 further includes an upper retaining ring 9, a spacer ring 11, and a lower retaining ring 12. Spacer rings 11 are installed between the main rubber sleeves 10. Two upper retaining rings 9 are installed outside the auxiliary pressure step 13-1 of the auxiliary rubber sleeve 13. Two lower retaining rings 12 are installed between the main rubber sleeve 10 and the auxiliary rubber sleeve 13. The outer circumference of the auxiliary rubber sleeve 13 has at least [missing information - likely a number or designation]. one Auxiliary pressure step 13-1; the sealing assembly outside the upper cone 14 is installed between the lower end of the upper connecting cylinder 6 and the outer circular step of the upper cone 14.

[0053] In a preferred embodiment: the sealing assembly installed outside the lower cone 17 has the same structure as the sealing assembly installed outside the upper cone 14; the center hole of the lower body of the upper top cylinder 19 installed outside the lower cone 17 matches the upper outer circle of the lower connecting cylinder 18, and the lower body of the upper top cylinder 19 can sit on the step formed by the upper outer circle and the middle outer circle of the lower connecting cylinder 18; a disc spring 20 is installed in the annular space formed by the upper top cylinder 19, the lower cone 17, and the lower connecting cylinder 18, and the disc spring 20 is located at the lower end of the lower cone 17; the outer circle of the lower connecting cylinder 18 is threaded to the lower cone 17 and has a sealing ring groove at its lower end; the sealing assembly outside the lower cone 17 is mounted together with the lower cone 17 by the disc spring 20 and the upper top cylinder 19, and the sealing assembly is equivalent to being installed outside the lower cone 17. The sealing assembly below the lower cone 17 is set and the disc spring 20 is stored by pressing from both ends of the slip 15.

[0054] In a preferred embodiment: the slip 15 is an arc-shaped block with anchor teeth 15-3 machined on its outer wall. A V-shaped anti-deformation groove 15-4 is machined axially within the anchor teeth 15-3. A retractable ring mounting groove 15-5 is machined circumferentially at the middle position of the anchor teeth 15-3. Conical surfaces 15-1 are machined facing each other at both ends of the inner arc surface of the slip 15. A dovetail-shaped mating groove 15-2 is machined on the conical surface 15-1. At least two slips 15 are installed outside the lower central tube 8. A retractable ring 16 is installed in the retractable ring mounting groove 15-5. The retractable ring 16 is a breakable ring with a stepped breakable groove 16-1 machined axially within its body. This makes the ring body on both sides of the breakable groove 16-1 elastic and improves the axial stability of the retractable ring 16.

[0055] In a preferred embodiment: the upper cone 14 is a cylindrical body with a non-uniform outer diameter. A shearing groove is provided on the upper part of the outer circle of the upper cone 14, and a sealing ring groove is provided on the lower part of the inner circle. The lower outer circle has a conical structure. A protruding dovetail-shaped key strip is provided in the conical structure of the lower outer circle of the upper cone 14 to mate with the mating groove 15-2 in the slip 15. The protruding dovetail-shaped key strip is set on the lower push body 14-1 at the lower part of the upper cone 14. The sealing assembly is installed on the outside of the upper outer circle of the upper cone 14.

[0056] In a preferred embodiment: the lower cone 17 is a cylindrical body with a non-uniform diameter, a sealing ring groove in its upper inner circle, and a conical structure in its upper outer circle; a protruding dovetail key strip is provided on the upper push body of the upper outer circle of the lower cone 17, which mates with the mating groove 15-2 in the slip 15; the lower cylindrical body of the lower cone 17 is located inside the upper top cylinder 19 and is threadedly connected to the lower connecting cylinder 18; an adapter ring 21 is also installed between the lower end of the upper top cylinder 19 and the sealing assembly; a step is provided between the lower outer circle of the lower connecting cylinder 18 and the upper inner circle of the lower top cylinder 22, and a shear pin groove is provided on the lower outer circle of the lower connecting cylinder 18, which can be fixed to the lower top cylinder 22 by shear pins.

[0057] In a preferred embodiment: the upper inner diameter of the connector 23 is smaller than the lower outer diameter of the lower connecting cylinder 18. When the packer is set, when the central tube string in the packer connected by the upper connector 1 moves relative to the string of parts connected outside the upper central tube 2 and the lower central tube 8, the shear pins between the upper central tube 2 and the locking upper cylinder 4, the upper connecting cylinder 6 and the upper cone 14, and the lower connecting cylinder 18 and the lower top cylinder 22 are cut off, and the lower connecting cylinder 18 and the upper parts can sit on the connector 23. The torque transmission cylinder 24 is a non-uniform diameter cylindrical body and the threads in the inner and outer circles at both ends can be connected to the connector 23 and the lower connector 27 respectively. In the inner circle of the middle part of the torque transmission cylinder 24, one or more spline grooves 24-1 are provided in the axial direction.

[0058] In a preferred embodiment: the upper end of the inner circle of the unsealing cylinder 25 is machined with an inner chamfer and has a sealing ring groove, a shear pin groove connected to the lower central tube 8, and a sitting step that cooperates with the inner circle step in the middle of the lower connector 27 on the outer circle; the upper outer wall of the shear cylinder 26 is machined with a number and structure of transmission splines 26-1 that cooperate with the spline groove 24-1 in the transmission cylinder 24, and an internal thread connected to the lower connecting cylinder 18 is machined in the inner circle above the inner circle step; one or more pawls 26-2 are provided at the lower part of the body of the shear cylinder 26, and a pawl protrusion 26-3 that cooperates with the inner circle step in the middle of the lower connector 27 is provided on the lower outer wall of the pawl 26-2. When the packer needs to be released, the shear pins between the release cylinder 25 and the lower connecting cylinder 18 are cut off. The release cylinder 25 falls and sits in the middle inner circle step of the lower connector 27. The pawl 26-2 in the shear cylinder 26 releases and disengages from the lower connector 27, releasing the lock between the shear cylinder 26 and the lower connector 27. Then, by lifting the central tube string connected to the upper connector 1 in this packer, the packer can be released.

[0059] In a preferred embodiment, the inner diameters of both the insertion tubing connecting ring 7 and the unsealing cylinder 25 are larger than the outer diameter of the downhole testing instrument. This facilitates the use of downhole instruments to collect data on the application effects and well parameters in the application well, and allows for adjustments to the well recovery plan.

[0060] Construction method for a downhole packer, comprising the following steps: A. First step, run the downhole packer into the application well: Connect the downhole packer to the delivery tool connected to the lower end of the delivery string via the upper connector 1 and shear pins, and run it into the set position in the well. First suspend it and then set it. a. Hydraulic setting of the downhole packer is performed on the surface. During this process, high-pressure fluid enters the delivery tool at the top of the packer. The outer cylinder at the bottom of the delivery tool pushes the locking upper cylinder 4 downward. Before the shear pins between the upper connecting cylinder 6 and the upper cone 14, and between the lower cone 17 and the lower top cylinder 22 are cut off, the slips 15 are first pushed to sit on the casing. When the pressure reaches the preset value, the shear pins between the upper connecting cylinder 6 and the upper cone 14, and between the lower cone 17 and the lower top cylinder 22 are cut off. Then, the two sets of sealing components installed on the outside of the upper cone 14 and the lower cone 17 are set from both the top and bottom directions, sealing the annulus.

[0061] b. After the packer is set, continue to increase the pressure, cut the shear pin connecting the upper connector 1 and the feed tool, complete the release between the feed string and the packer, and remove the feed string and the feed tool.

[0062] B. Second step, inserting the production tubing: Connect the insert pipe to the bottom of the production tubing, lower the production tubing into the well and insert it into the upper center pipe 2 of the downhole packer. The toothed thread on the outer circumference of the insert pipe engages with the return tubing connecting ring 7 to achieve the return insertion of the production tubing and the sealing lock with the downhole packer; at this point, the invention and the production tubing are ready for normal production applications.

[0063] In a preferred embodiment: when the wellhead above the packer needs to be operated later, the production string is rotated back on the surface, and the lower end of the insertion pipe is released from the back-insertion string connecting ring 7 in the packer, so that the production string and the lower end of the insertion pipe can be retrieved.

[0064] In a preferred embodiment: if the downhole packer needs to be retrieved in the later stages of use, a special retrieval string connected to the retrieval tool is lowered into the packer and the unsealing cylinder 25 is pushed downwards. The retrieval tool is then connected to the reinsertion string connecting ring 7, and the upper central pipe 2, lower central pipe 8, and unsealing cylinder 25 connected to the reinsertion string connecting ring 7 are retrieved, thereby unsealing the downhole packer and retrieving all other components in the downhole packer from the well.

[0065] The embodiments described above are merely typical examples, but the present invention is not limited to these embodiments. Those skilled in the art can make modifications without departing from the spirit and teachings of the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the inventive spirit and concept of the present invention should be included within the protection scope of the present invention. Therefore, the protection scope is not limited to the above description.

Claims

1. A downhole packer, comprising a setting mechanism and a releasing mechanism, characterized in that: The locking mechanism is equipped with an upper central tube (2) and a return insertion post connecting ring (7); The inner circle of the upper connector (1) is connected from top to bottom to the upper central tube (2) and the lower central tube (8) and the unsealing tube (25) of the insertion tube that can be inserted into the production column; The upper central tube (2) and the lower central tube (8) are connected from top to bottom to a locking mechanism, a sealing mechanism equipped with sealing components, and an unsealing mechanism, which are connected to the upper connecting cylinder (6), the lower connecting cylinder (18), the lower top cylinder (22), the connector (23), the torsion transmission cylinder (24), and the lower connector (27). The sealing assembly includes a main rubber sleeve (10) and an auxiliary rubber sleeve (13) installed on the outside of the upper cone (14) and lower cone (17) on both sides of the slip (15). The two sides of the slip (15) are connected to the upper cone (14) and lower cone (17) by keyways. The upper connecting sleeve (6) is connected to the upper cone (14) and the lower connecting sleeve (18) is connected to the lower top sleeve (22) by shear pins. A pawl-equipped shear tube (26) is installed between the transmission cylinder (24) in the unsealing mechanism and the lower central tube (8) and the unsealing cylinder (25). The unsealing cylinder (25) and the lower central tube (8) are connected by shear pins. The upper connector (1) can be connected to the feed string via shear pins; The insertion tube connection ring (7) can be connected to the insertion tube at the lower end of the production tube.

2. The downhole packer as described in claim 1, characterized in that, The locking mechanism is further provided with a locking ring (3), a locking upper cylinder (4), a locking lower cylinder (5), and a return insertion column connecting ring (7). The locking upper cylinder (4), which is connected to the locking ring (3), is sequentially threaded to the locking lower cylinder (5) and the upper connecting cylinder (6). The locking upper cylinder (4) is connected to the upper central tube (2) by a shear pin, and the locking ring (3) is installed in the annular space formed by the upper central tube (2), the locking upper cylinder (4), and the locking lower cylinder (5). The return insertion column connecting ring (7) is installed in the gap after the upper central tube (2) and the lower central tube (8) are threaded together, and the insertion protrusion (7-1) at the lower end is placed in the insertion groove (8-1) in the upper inner circle of the lower central tube (8) to limit the insertion of the lower end of the production column inserted into the upper central tube (2). The inner circle of the upper central tube (2) is a precision-machined sealing surface.

3. A downhole packer as described in claim 2, characterized in that, The internal threads of the locking ring (3) and the internal threads of the return insertion tube connecting ring (7) are both toothed threads and are matched with the toothed threads of the outer circle of the upper central tube (2) and the outer circle of the lower end insertion tube of the production tube, respectively; the locking ring (3) and the return insertion tube connecting ring (7) are both provided with a broken ring structure that penetrates the ring body and are respectively provided with an oblique broken groove one (3-1) and an axial broken groove two (7-2) in the ring body.

4. A downhole packer as described in claim 3, characterized in that, The lower central tube (8) is a non-uniform diameter cylindrical body with its upper outer circle and upper inner circle both larger than its lower outer circle and lower inner circle. At least one sealing ring groove is provided in the upper inner circle of the lower central tube (8), and an internal thread connecting to the upper central tube (2) is machined in the inner circle above the sealing ring groove. An insertion groove (8-1) is machined on the upper end face of the lower inner circle of the lower central tube (8) to match the number and structure of the insertion protrusions (7-1) in the insertion column connecting ring (7), allowing the insertion protrusions (7-1) to be inserted into the insertion groove (8-1). The lower end of the lower outer circle of the lower central tube (8) is provided with an external thread capable of connecting to the shear cylinder (26), and at least one internal thread is provided in the tube body above the external thread. one One screw hole.

5. A downhole packer as described in claim 2, characterized in that, The sealing assembly installed outside the upper cone (14) also includes an upper retaining ring (9), a spacer ring (11), and a lower retaining ring (12). The spacer ring (11) is installed between the main rubber cylinders (10). The two upper retaining rings (9) are installed outside the auxiliary pressure step (13-1) of the auxiliary rubber cylinder (13). The two lower retaining rings (12) are installed between the main rubber cylinder (10) and the auxiliary rubber cylinder (13). The outer circumference of the auxiliary rubber cylinder (13) is at least provided with one Auxiliary pressure step (13-1); the sealing assembly outside the upper cone (14) is installed between the lower end of the upper connecting cylinder (6) and the outer circular step of the upper cone (14).

6. A downhole packer as described in claim 5, characterized in that, The structure of the sealing assembly installed outside the lower cone (17) is the same as that of the sealing assembly installed outside the upper cone (14); the center hole of the lower body of the upper top cylinder (19) installed outside the lower cone (17) matches the upper outer circle of the lower connecting cylinder (18), and the lower body of the upper top cylinder (19) can sit on the step formed by the upper outer circle and the middle outer circle of the lower connecting cylinder (18); a disc spring (20) is installed in the annular space formed by the upper top cylinder (19), the lower cone (17) and the lower connecting cylinder (18), and the disc spring (20) is located at the lower end of the lower cone (17); the outer circle of the lower connecting cylinder (18) is threaded to the lower cone (17) and the lower end is provided with a sealing ring groove, and the sealing assembly outside the lower cone (17) is placed together with the lower cone (17) by the disc spring (20) and the upper top cylinder (19).

7. A downhole packer as described in claim 6, characterized in that, The slip (15) is an arc-shaped block with anchor teeth (15-3) machined on its outer wall. A V-shaped anti-deformation groove (15-4) is machined axially in the anchor teeth (15-3). A retractable ring mounting groove (15-5) is machined circumferentially in the middle position of the anchor teeth (15-3). Conical surfaces (15-1) are machined facing each other at both ends of the inner arc surface of the slip (15). A dovetail-shaped mating groove (15-2) is machined on the conical surface (15-1). At least two slips (15) are installed outside the lower central tube (8). A retractable ring (16) is installed in the retractable ring mounting groove (15-5). The retractable ring (16) is a disconnectable ring with a stepped disconnectable groove (16-1) machined axially in the ring body.

8. A downhole packer as described in claim 7, characterized in that, The upper cone (14) is a cylindrical body with a non-uniform outer circle. A shearing groove is provided on the upper part of the outer circle of the upper cone (14), a sealing ring groove is provided on the lower part of the inner circle, and the lower outer circle is a conical structure. A protruding dovetail key is provided in the conical structure of the lower outer circle of the upper cone (14) to mate with the mating groove (15-2) in the slip (15). The protruding dovetail key is set on the lower push body (14-1) at the lower part of the upper cone (14). The sealing assembly is installed on the outside of the upper outer circle of the upper cone (14).

9. A downhole packer as described in claim 7, characterized in that, The lower cone (17) is a cylindrical body with a non-uniform diameter. It has a sealing ring groove in its upper inner circle and a cone-shaped structure in its upper outer circle. A protruding dovetail key is provided on the upper push body of the upper outer circle of the lower cone (17) to cooperate with the mating groove (15-2) in the slip (15). The lower cylinder of the lower cone (17) is located inside the upper top cylinder (19) and is threadedly connected to the lower connecting cylinder (18). An adapter ring (21) is also installed between the lower end of the upper top cylinder (19) and the sealing assembly. The lower outer circle of the lower connecting cylinder (18) and the upper inner circle of the lower top cylinder (22) are provided with interlocking and matching steps. The lower outer circle of the lower connecting cylinder (18) is provided with a shear pin groove and can be fixed to the lower top cylinder (22) by shear pins.

10. A downhole packer as described in claim 2, characterized in that, The upper inner diameter of the connector (23) is smaller than the lower outer diameter of the lower connecting cylinder (18). The torque transmission cylinder (24) is a non-uniform diameter cylindrical body and the threads in the inner and outer circles at both ends can be connected to the connector (23) and the lower connector (27) respectively. In the inner circle of the middle part of the torque transmission cylinder (24), there is one or more spline grooves (24-1) in the axial direction.

11. A downhole packer as described in claim 2, characterized in that, The inner chamfer is machined at the upper end of the inner circle of the unsealing cylinder (25), and a sealing ring groove, a shear pin groove connected to the lower central tube (8), and a seat hanging step that cooperates with the inner circle step in the middle of the lower connector (27) are provided on the outer circle. The upper outer wall of the shear cylinder (26) is machined with a number and structure of transmission splines (26-1) that cooperate with the spline groove (24-1) in the transmission cylinder (24), and an internal thread connected to the lower connecting cylinder (18) is machined in the inner circle above the inner circle step. One or more pawls (26-2) are provided at the lower part of the body of the shear cylinder (26), and a pawl protrusion (26-3) that cooperates with the inner circle step in the middle of the lower connector (27) is provided on the lower outer wall of the pawl (26-2).

12. A downhole packer as described in claim 2, characterized in that, The inner diameters of the insertion string connecting ring (7) and the unsealing tube (25) are both larger than the outer diameter of the downhole testing instrument.

13. A construction method for any of the downhole packers described in claims 1-12, characterized in that, Includes the following steps: A. First step: Run a downhole packer into the application well. a. Hydraulically set the downhole packer on the surface; b. After the packer is set, continue to pressurize, cut the shear pin connecting the upper connector (1) and the feed tool, and release the feed string and the packer. Remove the feed string and the feed tool. B. Second step, insert the production tubing string: connect the insertion tube to the bottom of the production tubing string, lower the production tubing string into the well and insert it into the upper center tube (2) of the downhole packer.

14. The construction method as described in claim 13, characterized in that, When the wellhead above the packer needs to be operated in the later stage, the production string is rotated back on the ground and the lower end of the insertion pipe is released from the back insertion string connecting ring (7) in the packer, so that the production string and the lower end of the insertion pipe can be taken out.

15. The construction method as described in claim 13, characterized in that, If the downhole packer needs to be retrieved in the later stages of use, the special retrieval string connected to the retrieval tool is lowered into the packer and the unsealing cylinder (25) is pushed down. The retrieval tool is then connected to the reinsertion string connecting ring (7) to retrieve the upper central pipe (2), lower central pipe (8), and unsealing cylinder (25) connected to the reinsertion string connecting ring (7), thereby unsealing the downhole packer and retrieving all other components in the downhole packer from the well.

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