An ultra-high pressure permanent packer based on bidirectional slip anchoring

Abstract

This invention relates to the field of oil and gas extraction technology, and particularly to an ultra-high pressure permanent packer based on bidirectional slip anchoring. It includes a central tube and a hydraulic drive, multi-stage sealing, bidirectional anchoring, and unidirectional locking compensation assembly fitted thereon. The hydraulic drive assembly drives the sealing assembly to achieve radial sealing, and works in conjunction with an anti-extrusion retaining ring assembly to prevent high pressure overflow. The bidirectional slip assembly uses symmetrical cones to drive the slips to open, achieving bidirectional anchoring. The unidirectional locking compensation assembly uses a sawtooth thread for unidirectional limiting and dynamically compensates for the sealing and anchoring forces by using the potential energy stored in the compensation spring assembly. This application can solve problems such as uneven anchoring force, easy seal damage, and attenuation of setting force, improving the packer's sealing reliability under ultra-high pressure conditions.

Description

Technical Field

[0001] This invention relates to the field of oil and gas extraction technology, specifically to an ultra-high pressure permanent packer based on bidirectional slip anchoring. Background Technology

[0002] In permanent plugging operations of deep shale gas, tight oil and gas, ultra-deep high-temperature and high-pressure wells, and long-term sealed wells, packers must withstand axial pressure differentials, radial internal pressure, and external extrusion forces over long periods, and cope with axial loads caused by formation creep and pressure fluctuations. Existing permanent packers mostly adopt unidirectional slips or single-set cone sleeve push structures, which have technical limitations under complex working conditions, such as uneven anchoring force distribution, limited resistance to axial slippage, and insufficient pressure bearing capacity of sealing components.

[0003] One-way slip structures primarily resist unidirectional loads, and their stability fluctuates under alternating pressure impacts. The fitting precision between conventional tapered sleeves and slips needs improvement, resulting in limited slip penetration into the casing wall and a risk of slippage during long-term service. Sealing components often employ a single rubber sleeve structure, which is prone to bulging or tearing under the combined effects of high temperature, high pressure, and formation corrosion, posing a challenge to achieving zero leakage and high pressure resistance for permanent sealing. Furthermore, some packers lack an automatic anchoring force compensation mechanism after setting; if sealing performance deteriorates, on-site repair is cumbersome and may affect the long-term sealing effect of oil and gas wells. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides an ultra-high pressure-bearing permanent packer based on bidirectional slip anchoring. By setting a bidirectional symmetrical anchoring structure and a multi-stage composite sealing component, combined with a locking compensation mechanism with elastic potential energy storage function, it solves the technical defects in the prior art, such as uneven anchoring force distribution, insufficient axial anti-slip capability, easy damage of sealing components under high pressure environment, and decay of setting force over time.

[0005] To achieve the above objectives, the present invention provides an ultra-high pressure-bearing permanent packer based on bidirectional slip anchoring, comprising a central tube, wherein a hydraulic drive assembly, a multi-stage sealing sleeve assembly, a bidirectional slip anchoring assembly, and a unidirectional locking compensation assembly are sequentially sleeved on the outer periphery of the central tube from top to bottom; an upper connector is provided at the top end of the central tube and a lower connector is provided at the bottom end, both of which are connected to the central tube by threads; a hydraulic inlet is provided on the tube wall of the central tube, one end of which leads to the central flow channel of the central tube and the other end leads to the internal cavity of the hydraulic drive assembly.

[0006] Furthermore, the hydraulic drive assembly includes a piston outer cylinder and an annular piston disposed inside the piston outer cylinder. A sealed hydraulic chamber is formed between the piston outer cylinder and the outer wall of the central tube, and the hydraulic inlet is connected to the hydraulic chamber. The inner wall of the annular piston is provided with a first sealing groove, in which a first sealing ring is embedded. The outer wall of the annular piston is provided with a second sealing groove, in which a second sealing ring is embedded. The lower end of the annular piston abuts against a thrust transmission cylinder, which is sleeved on the outer periphery of the central tube.

[0007] Furthermore, the multi-stage sealing sleeve assembly includes an upper pressure ring, a first sleeve, a middle partition ring, a second sleeve, a lower pressure ring, and an anti-squeezing guard ring assembly sequentially sleeved on the central tube; the upper pressure ring is fixedly connected to the bottom end of the thrust transmission cylinder; the first sleeve and the second sleeve are both made of composite materials with different hardness, and the end of the first sleeve is provided with an inwardly recessed arc-shaped groove, and the two sides of the middle partition ring are provided with protrusions that match the arc-shaped groove; the anti-squeezing guard ring assembly is located below the lower pressure ring and includes multiple overlapping metal folded pieces, which unfold radially and fit against the inner wall of the sleeve under axial load.

[0008] Furthermore, the bidirectional slip anchoring assembly includes an upper cone, a lower cone, a bidirectional slip plate, and a slip retainer; the upper cone is sleeved on the central tube and located below the lower pressure ring, and the outer circumferential surface of the upper cone has a first inclined section; the lower cone is sleeved on the central tube and located below the upper cone, and the outer circumferential surface of the lower cone has a second inclined section, the first inclined section and the second inclined section have opposite inclination directions and are symmetrically distributed; the bidirectional slip plate is disposed between the upper cone and the lower cone, and the inner side of the bidirectional slip plate has a first mating surface and a second mating surface that slide and engage with the first inclined section and the second inclined section, respectively; the outer circumferential surface of the bidirectional slip plate has staggered carbide engagement teeth.

[0009] Furthermore, the bidirectional slip is circumferentially limited by the slip retainer, which is fixed to the outer wall of the central tube by shear pins; the bidirectional slip has a return spring cavity inside, and a tension spring is installed in the return spring cavity, with the two ends of the tension spring connected to two adjacent bidirectional slips respectively.

[0010] Furthermore, the one-way locking compensation assembly includes a locking sleeve, a one-way locking tooth ring, and a compensation spring assembly; the inner wall of the locking sleeve is provided with a first sawtooth thread, and the outer wall of the central tube is provided with a second sawtooth thread at a corresponding position. The first sawtooth thread and the second sawtooth thread form a one-way kinematic pair, restricting the locking sleeve from moving upward; the compensation spring assembly is disposed between the lower cone and the locking sleeve, and the compensation spring assembly is composed of multiple disc springs connected in series, and the compensation spring assembly is in a pre-compressed state.

[0011] Furthermore, the axial length of the hydraulic chamber is greater than the preset stroke of the annular piston, and the central tube has a locally thickened section at the corresponding position of the hydraulic inlet. The surface of the locally thickened section is hardened to accommodate the sliding of the first sealing ring.

[0012] Furthermore, the metal folded sheet in the anti-extrusion guard ring assembly is in a contracted cylindrical shape when not under pressure, and its outer diameter is smaller than the initial outer diameter of the first rubber tube; when the lower pressure ring applies an axial extrusion load, the metal folded sheet undergoes plastic deformation under force, and its outer edge expands outward to form an annular metal shielding layer, filling the radial gap between the central tube and the sleeve.

[0013] Furthermore, a dovetail guide groove is provided between the first mating surface of the bidirectional slip and the first inclined section of the upper cone, and the same dovetail guide groove is provided between the second mating surface and the second inclined section of the lower cone. The bidirectional slip moves radially in and out along the direction of the dovetail guide groove.

[0014] Furthermore, a protective shell is fitted around the outer periphery of the compensating spring assembly. The upper end of the protective shell is threaded to the lower cone, and the lower end is slidably connected to the locking sleeve. The interior of the protective shell is filled with lubricating grease.

[0015] Furthermore, the central tube is made of high-strength corrosion-resistant alloy steel, with a yield strength in the preset high-strength range, and has an anti-corrosion coating on its surface; a metal sealing ring is provided at the threaded connection between the upper connector and the lower connector.

[0016] During the sealing operation, high-pressure fluid enters the hydraulic inlet through the central channel of the central tube and then fills the hydraulic chamber. Under the action of hydraulic load, the annular piston moves downward against the friction between the first and second sealing rings, driving the thrust transmission cylinder downward. The thrust transmission cylinder transmits the axial load to the multi-stage sealing sleeve assembly. The upper pressure ring, the first sleeve, the middle diaphragm ring, the second sleeve, and the lower pressure ring undergo axial shortening and radial expansion under axial compression. The radial outer edges of the first and second sleeves adhere to the inner wall of the sleeve, forming a preliminary seal. As the axial load continues to increase, the anti-extrusion retaining ring assembly unfolds under the compression of the lower pressure ring, and the metal folded pieces form a metal support structure at both ends of the sleeve.

[0017] Meanwhile, the axial load continues to be transmitted downwards to the upper cone. When the load exceeds the preset shear strength of the shear pin, the shear pin breaks. Under the axial pressure, the upper and lower cones move towards the center, and the bidirectional slips, subjected to the radial thrust of the first and second inclined sections, open outwards along the dovetail guide groove. The carbide engagement teeth on the surface of the bidirectional slips embed into the sleeve wall, forming a bidirectional anchoring state. At this point, the axial load further compresses the compensation spring assembly, causing the disc spring to undergo elastic deformation and store elastic potential energy.

[0018] When the load is transferred to the one-way locking compensation assembly, the locking sleeve moves with the relative displacement of the central tube, and the first sawtooth thread and the second sawtooth thread mesh with each other. Due to the one-way limiting characteristic of the sawtooth thread, the locking sleeve cannot rebound in the opposite direction, thereby locking the setting load on the sealing sleeve and the two-way slip.

[0019] During long-term service, if fluctuations in formation temperature or pressure cause slight creep or volume shrinkage in the first or second rubber sleeve, the elastic potential energy originally stored in the compensation spring assembly will be released. The compensation spring assembly continuously acts on the lower cone, which converts this compensation force into a radial expansion force acting on the bidirectional slip and pushing the lower pressure ring upward, keeping the multi-stage sealing rubber sleeve assembly always under the preset compression state.

[0020] Compared with the closest existing technology, the present invention has the following advantages:

[0021] First, by setting up a bidirectional slip anchoring assembly, the present invention utilizes the symmetrical thrust of the upper and lower cones to generate a balanced biting force in the axial direction of the bidirectional slips, which significantly improves the anchoring stability of the packer when facing bidirectional alternating pressure differentials and eliminates the risk of slippage that may occur in unidirectional anchoring structures under pressure fluctuations.

[0022] Secondly, this invention employs a composite sealing system consisting of multi-stage rubber sleeves and anti-extrusion retaining rings. The metal shielding layer formed by the anti-extrusion retaining rings under pressure effectively prevents the rubber sleeves from "overflowing" or tearing from the gap between the central tube and the sleeve under high pressure. Combined with the first and second rubber sleeves with progressively different hardness, it achieves zero-leakage permanent sealing under ultra-high pressure conditions.

[0023] Third, this invention integrates a one-way locking compensation component, in which the compensation spring assembly can store and release elastic potential energy when necessary. This dynamic compensation mechanism solves the problem of the setting force of traditional packers decaying over time, enabling the packer to maintain its anchoring force and sealing specific pressure autonomously when facing complex working conditions such as formation creep and drastic temperature fluctuations, thus extending the service life of permanent sealing.

[0024] Fourth, the components of this invention adopt a modular design. The hydraulic drive component, sealing component, anchoring component and compensation component are axially connected and limited through the central tube. The structure is compact and the force transmission path is clear, which reduces energy loss in the setting process and improves the synchronization and reliability of the setting action.

[0025] Fifth, the invention ensures the consistency of the trajectory of the bidirectional slips during the opening process through the design of the dovetail guide groove and the reset spring cavity. In special cases where unsealing is required, the contraction force of the tension spring can assist the slips to retract smoothly, thereby enhancing the operational flexibility of the tool in complex wellbore environments.

[0026] Sixth, this invention uses high-strength corrosion-resistant alloy materials and a multi-stage sealing ring design to improve the overall corrosion resistance and pressure resistance of the packer, enabling it to meet the stringent operational requirements of deep shale gas and ultra-deep high-temperature and high-pressure wells, and reducing the overall risks and long-term maintenance costs of downhole operations. Attached Figure Description

[0027] Figure 1 This is a schematic cross-sectional view of the ultra-high pressure-bearing permanent packer based on bidirectional slip anchoring according to the present invention.

[0028] Figure 2 This is a partial cross-sectional structural diagram of the hydraulic drive assembly of the present invention;

[0029] Figure 3 This is a schematic diagram of the multi-stage sealing sleeve assembly of the present invention in the unsealed state;

[0030] Figure 4 This is an exploded structural diagram of the bidirectional slip anchoring assembly of the present invention;

[0031] Figure 5 This is a cross-sectional structural diagram of the unidirectional locking compensation component of the present invention.

[0032] Explanation of markings in the diagram:

[0033] 1. Central tube; 101. Upper connector; 102. Lower connector; 103. Hydraulic inlet; 104. Partially thickened section; 2. Hydraulic drive assembly; 201. Piston outer cylinder; 202. Annular piston; 203. Hydraulic chamber; 204. First sealing ring; 205. Second sealing ring; 206. Thrust transmission cylinder; 3. Multi-stage sealing rubber sleeve assembly; 301. Upper pressure ring; 302. First rubber sleeve; 303. Middle partition ring; 304. Second rubber sleeve; 305. Lower pressure ring; 306. Anti-extrusion guard ring assembly; 307. Metal folded plate; 4. Bidirectional slip anchoring assembly Components; 401. Upper cone; 402. Lower cone; 403. First inclined section; 404. Second inclined section; 405. Bidirectional slip; 406. Slip retainer; 407. Shear pin; 408. Carbide engagement tooth; 409. Return spring cavity; 410. Tension spring; 411. Dovetail guide groove; 5. One-way locking compensation assembly; 501. Locking sleeve; 502. One-way locking tooth ring; 503. First sawtooth thread; 504. Second sawtooth thread; 505. Compensation spring assembly; 506. Disc spring; 507. Protective housing. Detailed Implementation

[0034] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0035] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] Example 1:

[0037] The following is a reference to the appendix. Figure 1 To be continued Figure 5 This invention describes an ultra-high pressure permanent packer based on bidirectional slip anchoring.

[0038] In order to cope with the challenges of working in deep shale gas, ultra-deep high-temperature and high-pressure wells and long-term sealed wells, packers need to withstand extremely high axial pressure differentials and formation creep loads for a long time. Existing unidirectional anchoring structures are prone to uneven stress leading to slippage, and sealing elements are prone to plastic overflow under extremely high pressure differentials. In addition, the setting force decays over time, leading to sealing failure, which greatly increases the risks and maintenance costs of downhole operations.

[0039] Therefore, this ultra-high pressure-bearing permanent packer based on bidirectional slip anchoring includes a central tube 100. A hydraulic drive assembly 200 is sleeved on the outer periphery of the central tube 100. Below the hydraulic drive assembly 200, a multi-stage sealing sleeve assembly 300, a bidirectional slip anchoring assembly 400, and a one-way locking compensation assembly 500 are arranged in sequence. A fluid channel is provided inside the central tube 100. The central pressure is transmitted to the hydraulic drive assembly 200 through the hydraulic inlet 101 on the tube wall. After being pressurized, the hydraulic drive assembly 200 slides axially along the central tube 100, thereby pushing the multi-stage sealing sleeve assembly 300 to achieve radial sealing, and simultaneously driving the bidirectional slip anchoring assembly 400 to engage with the sleeve wall. The one-way locking compensation assembly 500 locks the setting load and stores elastic potential energy through a one-way substructure.

[0040] After the downhole tool reaches the preset depth, the surface pumping system applies a hydraulic load, and high-pressure fluid enters the hydraulic drive assembly 200. The linear motion of the hydraulic drive assembly 200 is converted into axial compressive force on the multi-stage sealing sleeve assembly 300, causing it to expand radially and conform to the casing. As the pressure increases, the upper and lower cones of the bidirectional slip anchoring assembly 400 move relative to each other, driving the slips to open radially and embed into the casing wall. The unidirectional locking compensation assembly 500 achieves unidirectional self-locking during axial displacement and compresses the internal elastic element, thereby releasing elastic potential energy during service to achieve dynamic compensation of sealing specific pressure and anchoring force.

[0041] The center tube 100 has an upper connector 102 at its top end and a lower connector 103 at its bottom end. Both the upper connector 102 and the lower connector 103 are connected to the center tube 100 by high-strength special threads. The center tube 100 has a locally thickened section 104 at the position corresponding to the hydraulic inlet 101. The surface of the locally thickened section 104 has been hardened.

[0042] In this embodiment, the main components of the packer are configured as shown in the table below:

[0043] Part Number Component Name Material requirements Core Functions 100 Central tube High-strength corrosion-resistant alloy steel Load support and fluid channel 201 Annular piston 42CrMo Pressure / displacement energy conversion 302 First glue tube Hydrogenated nitrile butadiene rubber (HNBR) High-hardness end support seal 403 Two-way slip Surface-mounted hard alloy Bidirectional axial load anchoring 503 Compensating spring assembly Chromium vanadium spring steel Stored potential energy and automatic compensation

[0044] like Figure 2 As shown, the hydraulic drive assembly 200 includes a piston outer cylinder 202, forming a hydraulic chamber 203 between the piston outer cylinder 202 and the central tube 100. An annular piston 201 is disposed within the hydraulic chamber 203. The lower end of the annular piston 201 abuts against a thrust transmission cylinder 204, which is sleeved around the outer periphery of the central tube 100. Specifically, the annular piston 201 achieves dynamic sealing through a first sealing ring and a second sealing ring, and its piston stroke has a 20% margin to ensure sufficient compression space under extreme operating conditions.

[0045] The number of multi-stage sealing sleeve assemblies 300 is set according to the pressure rating. In this embodiment, for example... Figure 3As shown, the multi-stage sealing cartridge assembly 300 includes a first cartridge 302 and a second cartridge 304, with the first cartridge 302 located above and the second cartridge 304 located below, separated by a spacer ring 303. In other embodiments of the invention, the number of cartridges may be increased to three or more stages.

[0046] The sealing modes include initial sealing mode, full pressure sealing mode, and compensated service mode;

[0047] In the initial sealing mode, the hydraulic drive assembly 200 pushes the first rubber sleeve 302 and the second rubber sleeve 304 to initially expand and contact the inner wall of the sleeve.

[0048] Under full-pressure sealing mode, the axial load increases further, and the anti-extrusion retaining ring assembly 306 is compressed and unfolds to form a metal shielding layer;

[0049] In the compensated service mode, when the rubber sleeve undergoes slight creep, the one-way locking compensation component 500 releases potential energy to maintain the seal.

[0050] In this embodiment, both the first rubber sleeve 302 and the second rubber sleeve 304 have inwardly recessed arc-shaped grooves at their ends, and the two sides of the partition ring 303 have matching protrusions. This conformal contact design can effectively disperse axial loads and avoid stress concentration. The anti-extrusion guard ring assembly 306 is located below the lower pressure ring 305 and is composed of multiple overlapping metal folded pieces.

[0051] like Figure 4 As shown, the bidirectional locking and anchoring assembly 400 includes an upper cone 401, a lower cone 402, and a bidirectional locking plate 403 disposed between the two. The upper cone 401 has a first inclined section, and the lower cone 402 has a second inclined section, with the two inclined sections having opposite inclination directions. The inner side of the bidirectional locking plate 403 has a dovetail guide groove 406 that slides with the first and second inclined sections.

[0052] When the setting load is transferred to the upper cone 401, the shear pin 405 breaks, and the upper cone 401 and lower cone 402 move closer together, driving the bidirectional slip 403 to open radially outward through the dovetail guide groove 406. The outer circumferential surface of the bidirectional slip 403 is provided with staggered carbide engagement teeth, and its engagement depth is controlled by the stroke of the cone to ensure maximum anchoring force without damaging the strength of the casing.

[0053] Adjacent bidirectional locking slips 403 are connected by tension springs, which are installed in the return spring cavity. When unsealing is required, after the axial lock is released, the contraction force of the tension springs assists the bidirectional locking slips 403 to retract along the dovetail guide groove 406, restoring them to their initial outer diameter.

[0054] like Figure 5As shown, the one-way locking compensation assembly 500 includes a locking sleeve 501. The inner wall of the locking sleeve 501 is provided with a first serrated thread, and the outer wall of the central tube 100 is provided with a second serrated thread. The first serrated thread and the second serrated thread form a one-way kinematic pair, allowing the locking sleeve 501 to move downward while restricting its upward rebound. A compensation spring assembly 503 is disposed between the lower cone 402 and the locking sleeve 501, and is composed of multiple disc springs connected in series.

[0055] To protect the core precision mechanism, a protective outer shell 504 is provided on the outside of the compensating spring assembly 503, and the interior of the protective outer shell 504 is filled with high-temperature resistant lubricating grease. The surface of the central tube 100 is provided with three layers of anti-corrosion coating to resist corrosion.

[0056] Ground engineers determine the setting status by monitoring the "pressure-displacement" curve of the pump injection pressure. When a significant jump point appears on the pressure curve (corresponding to the breakage of shear pin 405) and the pressure subsequently rises steadily to the stabilizing range, it confirms that the bidirectional slip 403 has successfully engaged. If there is no pressure fluctuation during the stabilization process, it indicates that the unidirectional locking compensation component 500 has entered the locked state.

[0057] During service, if abnormal fluctuations in annular pressure are detected at the wellhead, it indicates that the seal may be affected by formation creep. In this case, the compensation spring assembly 503 in the one-way locking compensation component 500 will automatically release its elastic displacement. According to experimental data, when the rubber sleeve undergoes a 5% volume shrinkage, the compensation load provided by the compensation spring assembly 503 can still maintain the sealing specific pressure greater than 1.2 times the wellbore pressure differential, ensuring the permanence of the seal.

[0058] This invention significantly improves the reliability of packers under ultra-high pressure environments through a bidirectional symmetrical anchoring structure and a multi-stage composite sealing system, combined with an elastic potential energy compensation mechanism. The bidirectional slip 403 utilizes symmetrical thrust to balance axial loads and eliminate the risk of slippage; the metal shielding layer formed by the anti-extrusion retaining ring assembly 306 solves the problem of packer overflow; and the unidirectional locking compensation component 500 overcomes the industry pain point of setting force attenuation, greatly extending the service life of permanent seals.

[0059] To enable those skilled in the art to fully understand and implement this invention, the specific implementation principles of this invention are further supplemented below with a specific application scenario.

[0060] Step 1: During the downhole operation and initial hydraulic drive, the packer is connected to the lower part of the production tubing via the upper connector 101, and lowered to the predetermined permanent sealing depth of the formation. High-pressure fluid is then pumped from the surface, entering the hydraulic inlet 103 through the inner cavity of the central tube 1. Since the hydraulic inlet 103 penetrates the locally thickened section 104 and leads to the hydraulic chamber 203, the high-pressure fluid generates axial thrust within the hydraulic chamber 203, driving the annular piston 202 to overcome the static friction between the first sealing ring 204 and the second sealing ring 205 and begin to move downwards. During this process, the annular piston 202 pushes the thrust transmission cylinder 206 downwards synchronously, converting hydraulic energy into axial mechanical load and transmitting it to the multi-stage sealing sleeve assembly 3.

[0061] Step 2: During the multi-stage composite sealing process, the thrust transmission cylinder 206 first compresses the upper pressure ring 301, thereby compressing the first rubber sleeve 302, the middle partition ring 303, and the second rubber sleeve 304 axially. Because the arc-shaped grooves at the ends of the first rubber sleeve 302 and the second rubber sleeve 304 conformally contact the protruding structure of the middle partition ring 303, the axial compressive load is uniformly guided to the middle of the rubber sleeve, causing it to expand radially and tightly adhere to the inner wall of the sleeve. Simultaneously, the axial load continues to be transmitted downwards to the lower pressure ring 305, compressing the lower anti-extrusion guard ring assembly 306. The metal folded pieces 307 in the anti-extrusion guard ring assembly 306 plastically unfold under pressure, forming annular metal shielding layers at the upper and lower ends of the rubber sleeve. This physically blocks any overflow channels that may occur under ultra-high pressure, ensuring the stability of the sealing pressure.

[0062] Step 3: During bidirectional symmetrical anchoring, the axial load is applied downwards to the upper cone 401 via the multi-stage sealing sleeve assembly 3. When the pumping pressure rises to the preset value and the resulting axial force exceeds the shear strength of the shear pin 407, the shear pin 407 is sheared, releasing the relative fixation between the upper cone 401 and the central tube 1. Subsequently, the upper cone 401 and the lower cone 402 approach each other under the action of axial pressure, and the bidirectional slip 405 is squeezed by the first inclined section 403 and the second inclined section 404, sliding radially outward along the dovetail guide groove 411. The hard alloy engagement teeth 408 on the outer periphery of the bidirectional slip 405 then embed into the sleeve wall. Because the inclination directions of the upper and lower inclined sections are opposite, the bidirectional slip 405 can resist both upward and downward axial loads simultaneously. Through this symmetrical force principle, the risk of displacement caused by pressure difference reversal is eliminated.

[0063] Step four, during unidirectional locking and potential energy storage, with the bidirectional locking slip 405 fully anchored, the axial load continues to act downwards on the unidirectional locking compensation assembly 5. The lower cone 402 presses downwards against the compensation spring assembly 505, causing multiple series-connected disc springs 506 to undergo elastic deformation and store a large amount of elastic potential energy. Simultaneously, the locking sleeve 501 moves downwards with the load, and its inner wall's first sawtooth thread 503 engages tooth-by-tooth with the outer wall's second sawtooth thread 504. Due to the unidirectional anti-reverse characteristic of the sawtooth thread, after the pumping pressure is released, the locking sleeve 501 cannot rebound upwards under the limiting action of the unidirectional locking ring 502, thus permanently locking the initial setting load within the internal mechanism.

[0064] Step 5: During dynamic compensation in long-term service, after the packer enters long-term storage, if a slight volume shrinkage occurs due to a decrease in formation temperature or fatigue of the rubber sleeve material, the sealing interface pressure may show a downward trend. At this time, the compensation spring assembly 505, which is in a compressed state, will spontaneously release the stored elastic potential energy, pushing the lower cone 402 to move slightly upward. According to the wedge force amplification principle, the upward displacement of the lower cone 402 will continuously apply radial expansion force to the bidirectional slip 405 through the second inclined section 404, and squeeze the multi-stage sealing rubber sleeve assembly 3 upward. Through this automatic displacement compensation, the sealing specific pressure is always maintained above the safe threshold, realizing long-term autonomous maintenance of sealing performance without ground intervention.

[0065] All content not described in detail in this specification is prior art known to those skilled in the art. The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

[0066] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0067] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0068] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0069] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0070] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A dual slip anchor based ultra-high pressure permanent packer, comprising: The device includes a central tube (1), and the outer periphery of the central tube (1) is fitted with a hydraulic drive assembly (2), a multi-stage sealing sleeve assembly (3), a bidirectional slip anchoring assembly (4), and a one-way locking compensation assembly (5) from top to bottom. The central tube (1) has an upper connector (101) at the top and a lower connector (102) at the bottom. The upper connector (101) and the lower connector (102) are both connected to the central tube (1) by threads. The central tube (1) has a hydraulic inlet hole (103) on its wall. One end of the hydraulic inlet hole (103) leads to the central flow channel of the central tube (1), and the other end leads to the internal cavity of the hydraulic drive assembly (2).

2. The ultra-high pressure-bearing permanent packer based on bidirectional slip anchoring as described in claim 1, characterized in that, The hydraulic drive assembly (2) includes a piston outer cylinder (201) and an annular piston (202) disposed inside the piston outer cylinder (201). A sealed hydraulic chamber (203) is formed between the piston outer cylinder (201) and the outer wall of the central tube (1). The hydraulic inlet (103) communicates with the hydraulic chamber (203). The inner wall of the annular piston (202) is provided with a first sealing groove, in which a first sealing ring (204) is embedded. The outer wall of the annular piston (202) is provided with a second sealing groove, in which a second sealing ring (205) is embedded. The lower end of the annular piston (202) abuts against a thrust transmission cylinder (206), which is sleeved on the outer periphery of the central tube (1).

3. The ultra-high pressure-bearing permanent packer based on bidirectional slip anchoring according to claim 2, characterized in that, The multi-stage sealing rubber sleeve assembly (3) includes an upper pressure ring (301), a first rubber sleeve (302), a middle partition ring (303), a second rubber sleeve (304), a lower pressure ring (305), and an anti-squeezing guard ring assembly (306) sequentially sleeved on the central tube (1); the upper pressure ring (301) is fixedly connected to the bottom end of the thrust transmission cylinder (206); the first rubber sleeve (302) and the second rubber sleeve (304) are made of composite materials with different hardness, and the end of the first rubber sleeve (302) is provided with an inwardly recessed arc groove, and the two sides of the middle partition ring (303) are provided with protrusions that match the arc groove; the anti-squeezing guard ring assembly (306) is located below the lower pressure ring (305) and includes multiple overlapping metal folded pieces (307). Under axial load, the metal folded pieces (307) unfold radially and fit against the inner wall of the sleeve.

4. The ultra-high pressure-bearing permanent packer based on bidirectional slip anchoring according to claim 3, characterized in that, The bidirectional slip anchoring assembly (4) includes an upper cone (401), a lower cone (402), bidirectional slip pieces (405), and a slip retainer (406); the upper cone (401) is sleeved on the central tube (1) and located below the lower pressure ring (305), and the outer circumferential surface of the upper cone (401) is provided with a first inclined section (403); the lower cone (402) is sleeved on the central tube (1) and located below the upper cone (401), and the outer circumferential surface of the lower cone (402) is provided with a second inclined section. (404), the first inclined section (403) and the second inclined section (404) are inclined in opposite directions and are symmetrically distributed; the bidirectional slip (405) is disposed between the upper cone (401) and the lower cone (402), and the inner side of the bidirectional slip (405) is provided with a first mating surface and a second mating surface that slide and engage with the first inclined section (403) and the second inclined section (404) respectively; the outer peripheral surface of the bidirectional slip (405) is provided with staggered hard alloy biting teeth (408).

5. A permanent packer with ultra-high pressure bearing capacity based on bidirectional slip anchoring as described in claim 4, characterized in that, The bidirectional slip (405) is circumferentially limited by the slip retainer (406), and the slip retainer (406) is fixed to the outer wall of the central tube (1) by a shear pin (407); the bidirectional slip (405) is provided with a reset spring cavity (409), and a tension spring (410) is installed in the reset spring cavity (409), and the two ends of the tension spring (410) are respectively connected to two adjacent bidirectional slips (405).

6. The ultra-high pressure-bearing permanent packer based on bidirectional slip anchoring according to claim 4, characterized in that, The one-way locking compensation assembly (5) includes a locking sleeve (501), a one-way locking tooth ring (502), and a compensation spring assembly (505). The inner wall of the locking sleeve (501) is provided with a first sawtooth thread (503), and the outer wall of the central tube (1) is provided with a second sawtooth thread (504) at the corresponding position. The first sawtooth thread (503) and the second sawtooth thread (504) form a one-way motion pair, which restricts the locking sleeve (501) from moving upward. The compensation spring assembly (505) is disposed between the lower cone (402) and the locking sleeve (501). The compensation spring assembly (505) is composed of multiple disc springs (506) connected in series, and the compensation spring assembly (505) is in a pre-compressed state.

7. The ultra-high pressure-bearing permanent packer based on bidirectional slip anchoring according to claim 2, characterized in that, The axial length of the hydraulic chamber (203) is greater than the preset stroke of the annular piston (202). The central tube (1) has a locally thickened section (104) at the corresponding position of the hydraulic inlet (103). The surface of the locally thickened section (104) is hardened to cooperate with the sliding of the first sealing ring (204).

8. The ultra-high pressure-bearing permanent packer based on bidirectional slip anchoring according to claim 3, characterized in that, The metal folded piece (307) in the anti-squeezing guard ring assembly (306) is in a contracted cylindrical shape when not under pressure, and its outer diameter is smaller than the initial outer diameter of the first rubber tube (302). When the lower pressure ring (305) applies an axial compression load, the metal folded piece (307) undergoes plastic deformation under force, and its outer edge expands outward to form an annular metal shielding layer, filling the radial gap between the central tube (1) and the sleeve.

9. A permanent packer with ultra-high pressure bearing capacity based on bidirectional slip anchoring as described in claim 4, characterized in that, A dovetail guide groove (411) is provided between the first mating surface of the bidirectional slip (405) and the first inclined section (403) of the upper cone (401), and the same dovetail guide groove (411) is provided between the second mating surface and the second inclined section (404) of the lower cone (402). The bidirectional slip (405) performs radial extension and retraction movement along the direction of the dovetail guide groove (411).

10. A permanent packer with ultra-high pressure bearing capacity based on bidirectional slip anchoring as described in claim 6, characterized in that, The outer periphery of the compensation spring assembly (505) is fitted with a protective shell (507). The upper end of the protective shell (507) is connected to the lower cone (402) by a thread, and the lower end is connected to the locking sleeve (501) by a sliding fit. The interior of the protective shell (507) is filled with lubricating grease.

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