A compression type external casing packer based on low carbon exploitation of petroleum

Abstract

The application discloses a compression type external casing packer based on low-carbon oil exploitation, and relates to the technical field of oilfield downhole tools.The packer comprises a casing, and a micro-deformation adjusting mechanism is arranged in the casing;when the packer is in the installation process, the micro-deformation adjusting mechanism is in the contraction state, so that the packer can be smoothly lowered into the casing.In the device, the rubber cylinder assembly is designed in a multi-section combined mode, a plurality of cylindrical rubber cylinders are sequentially connected in the axial direction, the multi-section cylindrical rubber cylinders can realize differential adaptation through cooperative deformation, the rubber cylinder at the corresponding position can more fully expand radially to fill the gap for the local diameter expansion section of the casing inner wall, and the expansion amount can be moderately controlled to avoid excessive extrusion for the local diameter reduction section.Meanwhile, the contact area of the multi-section rubber cylinder and the casing inner wall is larger, the sealing surface contact pressure can be effectively dispersed, and a uniform and stable sealing pressure field is formed in the whole well section.

Description

Technical Field

[0001] This invention relates to the field of oilfield downhole tool technology, specifically to a compression-type external packer based on low-carbon oil extraction. Background Technology

[0002] A compression-type external packer based on low-carbon oil extraction is mainly used for environmentally friendly stratified extraction and casing protection operations in oil and gas wells. Its core structure adopts a compression-type sealing design, which uses external pressure to make the rubber sleeve radially expand and form an interference seal with the casing wall. It is suitable for scenarios such as water injection wells and acid fracturing, and can effectively isolate the intrusion of high-pressure fluids into non-target formations, reduce the risk of casing damage, and reduce ineffective energy consumption.

[0003] However, existing technologies still have the following drawbacks in practical applications:

[0004] 1. In the existing single-segment rubber sleeve design of compression packers, the rubber sleeve is an integral structure with a fixed radial expansion. When facing irregular wellbores (such as local expansion, contraction, well wall unevenness, or excessive casing ellipticity), the rubber sleeve cannot expand differently according to the wellbore shape. In the expansion area, the rubber sleeve is difficult to completely fit the well wall after expansion, forming a sealing gap. In the contraction area, the rubber sleeve is prone to local stress concentration due to excessive compression. At the same time, the contact area between the single-segment rubber sleeve and the well wall is limited, resulting in a dispersed and small overall contact pressure on the sealing surface, which cannot form a uniform and stable sealing pressure field throughout the well section.

[0005] When a single-section packer cannot be adapted to an irregular wellbore due to the aforementioned problems, the packer may experience localized sealing failure. This manifests as inter-layer fluid cross-flow (such as water flowing from a high-pressure layer to an oil layer, or gas flowing from a high-gas-bearing layer to a low-production layer), directly leading to a decrease in the target reservoir's production efficiency (such as a surge in crude oil water cut and an imbalance in the gas-oil ratio). If the contact pressure at the sealing surface remains low, during long-term high-pressure injection and production operations (such as fracturing and water-driven oil recovery), the fluid pressure is prone to breaching the weak sealing area, causing abnormal stress on the tubing string inside the wellbore (such as tubing string vibration and axial movement). This not only increases the difficulty of wellhead equipment operation and maintenance but may also lead to an increase in the frequency of well workover operations, significantly increasing the time and economic costs of oilfield development.

[0006] 2. Existing compression packers achieve anchoring and fixation within the wellbore by expanding the upper and lower jaws through rotational motion. However, this method has significant drawbacks in complex well conditions or long-term operations. The core issues are concentrated in three aspects: anchoring reliability, wellbore adaptability, and tool safety, as detailed below:

[0007] The chucks cause significant damage to the inner wall of the wellbore and have limited adaptability: They achieve anchoring by mechanically biting into the inner wall of the casing. If there is corrosion or cracks on the inner wall of the casing (a common problem in old wells), or if the open hole wall is made of soft sandstone, the chucks can easily aggravate casing damage (such as scratching the inner wall or enlarging cracks) when they are inserted, and may even lead to the collapse of the open hole wall. In addition, the chucks are fixed in size and cannot be adapted to irregular wellbores (such as elliptical casings or locally reduced diameter sections), which can easily lead to problems such as "insufficient biting force" or "excessive compression that damages the wellbore".

[0008] Poor anchoring stability and susceptible to fluctuations in operating conditions: The chuck anchoring relies on "point / line contact engagement" with a small contact area. When the fluid pressure inside the wellbore fluctuates drastically, or when the tubing undergoes axial expansion and contraction due to temperature changes, the chuck is prone to "slipping off" from the inner wall of the casing, causing the packer to move axially and damaging the rubber sleeve seal.

[0009] Unsealing is difficult: After the jaws are set, they are tightly engaged, especially during long-term high-temperature and high-pressure operations. The jaws may become stuck due to metal fatigue or wellbore impurities (such as scale and sand particles) and cannot be retracted normally. Forcibly unsealing can easily lead to jaw breakage, with broken pieces remaining in the wellbore (which may block the tubing string and damage subsequent tools). If the jaws are completely stuck, complex well workover operations (such as milling) are required to remove them, increasing operating costs and wellbore risks.

[0010] Therefore, in view of this, the present invention proposes a compression-type external packer based on low-carbon oil extraction to make up for and improve the shortcomings of the prior art. Summary of the Invention

[0011] To address the aforementioned technical problems, this invention provides a compression-type external packer based on low-carbon oil extraction, thereby resolving the technical issues raised in the background section.

[0012] To achieve the above objectives, the technical solution adopted by this invention is as follows: a compression-type external packer based on low-carbon oil extraction, comprising a casing, wherein a micro-deformation adjustment mechanism is provided inside the casing. When the packer is in the installation process, the micro-deformation adjustment mechanism is in a contracted state to ensure that the packer can be smoothly lowered into the casing; when the packer is in the setting process, the micro-deformation adjustment mechanism is in an expanded state, and the expansion achieves an interference seal with the inner wall of the casing, separating different layers of the oil and gas well and facilitating low-carbon oil extraction.

[0013] Furthermore, the casing is coaxially assembled from top to bottom along the axial direction with an oil pipe, a packer outer shell, and a packer central tube. The oil pipe is located in the upper part of the inner side of the casing, and its lower end is coaxially connected to the top of the packer central tube, forming the main channel for downhole fluid transmission. The packer outer shell is correspondingly arranged in the middle part of the inner side of the casing, and is coaxially sleeved on the outside of the packer central tube with the packer central tube as the axis, forming a double-layer nested structure to provide spatial support.

[0014] Furthermore, the micro-deformation adjustment mechanism includes a rubber sleeve assembly, which is coaxially mounted on the outer periphery of the packer housing to form a radial linkage structure with the housing. The rubber sleeve assembly adopts a multi-segment combination design, and its whole is composed of no less than three cylindrical rubber sleeves connected in series along the axial direction. The adaptability to irregular wellbores is improved by the coordinated deformation of the multiple rubber sleeves, and each cylindrical rubber sleeve is symmetrically equipped with expansion and contraction rings at both the upper and lower ends.

[0015] Furthermore, in the rubber tube assembly, the expansion and contraction opening located above the cylindrical rubber tube has a funnel-shaped structure with an axial cross-section that is narrower at the top and wider at the bottom, with its small diameter end facing upwards and its large diameter end adapted to and connected to the top of the cylindrical rubber tube; the expansion and contraction opening located below the cylindrical rubber tube has a funnel-shaped structure with an axial cross-section that is wider at the top and narrower at the bottom, with its large diameter end facing upwards and adapted to and connected to the bottom of the cylindrical rubber tube, and its small diameter end facing downwards.

[0016] Furthermore, during the installation and lowering process, all the expansion and contraction rings are in a contracted state, and the diameter of the expansion and contraction ring outlets is smaller than the diameter of the cylindrical rubber tube in the rubber tube assembly, ensuring that the packer as a whole passes smoothly through the internal space of the sleeve.

[0017] Furthermore, when the equipment is in the setting and sealing process, the expansion and contraction rings are all in an expanded state, and the diameter of the expansion and contraction ring outlets is consistent with the diameter of the cylindrical rubber tube in the rubber tube assembly. By matching the diameter of the expansion and contraction rings with that of the cylindrical rubber tube, the integrity of the sealing surface and the reliability of the fit are ensured.

[0018] Furthermore, a spacer ring is coaxially assembled between adjacent expansion and contraction rings. A ring-shaped limiting buckle is fixedly connected to the inner wall of the spacer ring. Movable protrusions are evenly distributed along the circumferential direction on the outer circumferential surface of the limiting buckle, and the movable protrusions are slidably connected to the limiting buckle. The upper end of each movable protrusion is fixedly connected to the lower end of the upper expansion and contraction ring, and the lower end of the movable protrusion is fixedly connected to the upper end of the lower expansion and contraction ring, forming a linkage structure between the expansion and contraction ring and the spacer ring.

[0019] Furthermore, each of the movable protrusions has an arc groove on its radial outer side wall. An elastic connecting cable is installed in the arc groove. Several movable protrusions form a circumferentially closed integrated linkage structure through the elastic connecting cable. The elastic connecting cable passes through each arc groove along the circumference of the movable protrusion. The outer wall of the elastic connecting cable is uniformly fixedly connected with a dividing cylinder. Each dividing cylinder is correspondingly embedded in the center gap between two adjacent movable protrusions, forming a circumferentially distributed interval positioning structure for the movable protrusions.

[0020] Furthermore, the upper and lower ends of the rubber sleeve assembly are symmetrically equipped with rigid retaining rings, which are all fitted to the inner wall of the sleeve, and the rigid retaining rings are all made of boron nitride material.

[0021] Furthermore, each of the hard retaining rings has an integrated ring installed inside. An elastic interlayer is installed on the side of the integrated ring away from the hard retaining ring. The integrated ring is composed of several inclined pieces, each of which is made of shape memory alloy.

[0022] Compared with the prior art, the beneficial effects of the present invention are:

[0023] (1) Compared with the existing single-section rubber sleeve, which is prone to problems such as loose fit in the expansion area and stress concentration in the contraction area when facing irregular wellbores due to its integral structure and fixed radial expansion amount, the rubber sleeve assembly in this device adopts a multi-section combination design, which is composed of no less than three cylindrical rubber sleeves connected in series along the axial direction. The multi-section cylindrical rubber sleeves can achieve differentiated adaptation through coordinated deformation. For the local expansion section of the casing inner wall, the corresponding rubber sleeve can expand radially more fully to fill the gap. For the local contraction section, the expansion amount can be moderately controlled to avoid excessive compression. At the same time, the contact area between the multi-section rubber sleeve and the casing inner wall is larger, which can effectively disperse the contact pressure of the sealing surface and form a uniform and stable sealing pressure field in the whole well section, reducing the risk of abnormal stress on the tubing string during high-pressure injection and production operations, and reducing the difficulty of wellhead equipment operation and maintenance and well repair costs.

[0024] Most importantly, the symmetrical expansion and contraction rings at both ends of each cylindrical rubber tube can synchronously switch between contraction and expansion states according to different operating conditions of the equipment, providing key guarantees for packer installation and setting: During the installation and lowering stage, the expansion and contraction rings are synchronously in a contracted state, with their output diameter smaller than the diameter of the cylindrical rubber tube. The funnel-shaped structure, narrower at the top and wider at the bottom, and the funnel-shaped structure, wider at the top and narrower at the bottom, form a streamlined shape with "narrowing at both ends." Combined with the contracted state of the rubber tube assembly, this significantly reduces the contact area and frictional resistance with the inner wall of the sleeve, avoiding scraping and jamming during installation and ensuring that the packer descends smoothly to the target layer. After entering the setting stage, the expansion and contraction rings expand synchronously with the expansion of the rubber tube, with the output diameter consistent with the diameter of the cylindrical rubber tube. The upper expansion and contraction rings can guide the uniform extension of the upper end of the rubber tube, while the lower expansion and contraction rings can constrain the expansion direction of the lower end of the rubber tube, preventing tearing or extrusion at the end of the rubber tube due to stress concentration, ensuring the integrity and reliable fit of the sealing surface, and laying the structural foundation for subsequent interference sealing.

[0025] (2) During the setting process, the moving protrusion slides radially along the outer circumferential surface of the limiting ring buckle. At the same time, the elastic connecting cable stretches as the moving protrusion unfolds. The dividing cylinder on its outer wall stabilizes the gap between adjacent protrusions. This linkage structure further optimizes the sealing effect of the multi-section rubber sleeve. Through the sliding cooperation between the moving protrusion and the limiting ring buckle, the expansion range of the expansion ring can be controlled to avoid excessive or insufficient expansion of the rubber sleeve in some areas. The synergistic effect of the elastic connecting cable and the dividing cylinder can ensure that the multi-section rubber sleeve deforms uniformly in the circumferential direction. Even when facing irregular shapes such as local concavity and convexity of the inner wall of the casing, each section of the rubber sleeve can be tightly fitted to the well wall through segmented compensation, ensuring uniform distribution of sealing pressure, effectively separating different layers of oil and gas wells, reducing ineffective production energy consumption caused by interlayer fluid flow, and meeting the needs of low-carbon oil production.

[0026] (3) This device can also improve the reliability of the packer in long-term operation by introducing a dynamic sealing adjustment structure consisting of a hard retaining ring, an integrated ring, and an elastic interlayer. The hard retaining ring is made of boron nitride material with excellent thermal conductivity, which can quickly absorb the heat conducted by the formation and the heat of fluid friction in the well, and transfer the heat to the integrated ring composed of nickel-titanium shape memory alloy inclined plates. When the nickel-titanium shape memory alloy is heated, it expands thermally, causing the inclined plates to open outward and squeeze the elastic interlayer. The reaction force of the elastic interlayer pushes the hard retaining ring to fit more tightly against the inner wall of the casing, effectively compensating for the sealing gap caused by temperature changes or long-term use, and avoiding the sealing failure problem caused by the sealing gap in the existing packer. When the downhole temperature decreases, the nickel-titanium shape memory alloy inclined plates return to their initial shape, preventing the hard retaining ring from excessively squeezing the casing and causing damage, thus realizing the dynamic adjustment of "thermal expansion compensation and cold contraction reset". This structure not only extends the service life of the packer and reduces the frequency of well workover caused by sealing failure, but also reduces the additional energy consumption and carbon emissions brought about by well workover operations, further contributing to the realization of the goal of low-carbon oil extraction. Attached Figure Description

[0027] Figure 1 This is a front-view three-dimensional structural schematic diagram of the present invention;

[0028] Figure 2 This is a schematic diagram of the planar structure of the present invention in the empty wellbore state;

[0029] Figure 3 This is a three-dimensional structural diagram of the rubber sleeve assembly in the empty wellbore state of the present invention;

[0030] Figure 4 This is a schematic diagram of the planar structure of the rubber sleeve assembly in the empty wellbore state of the present invention;

[0031] Figure 5 This is an exploded view of the hardware retaining ring and other components of the present invention;

[0032] Figure 6 This is a schematic diagram of the internal three-dimensional structure of the hardware retaining ring of the present invention;

[0033] Figure 7 This is a top-view structural diagram showing the positional relationship between the rigid retaining ring and the integrated folding plate of the present invention.

[0034] Figure 8 This is a three-dimensional structural diagram of the glue cartridge assembly in the set-sealing state of the present invention;

[0035] Figure 9 This is a schematic diagram of the planar structure of the glue cartridge assembly in the set-sealing state of the present invention;

[0036] Figure 10 This is a three-dimensional structural diagram of the internal components of the spacer ring compartment of the present invention.

[0037] The numbers on the map are:

[0038] 1. Casing; 2. Oil tubing; 3. Packer housing; 4. Packer center tube; 5. Micro-deformation adjustment mechanism; 51. Sleeve assembly; 52. Expansion / contraction ring; 53. Spacer ring compartment; 54. Limiting buckle; 55. Moving protrusion; 56. Arc groove; 57. Elastic connecting cable; 58. Separating cylinder; 59. Rigid retaining ring; 510. Integrated ring; 511. Elastic interlayer. Detailed Implementation

[0039] 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, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0040] Example 1

[0041] Please refer to Figure 1 - Figure 2 As shown, a compression-type external packer for low-carbon oil extraction includes a casing 1. The casing 1 is equipped with a micro-deformation adjustment mechanism 5. When the packer is being installed, the micro-deformation adjustment mechanism 5 is in a contracted state to ensure that the packer can be smoothly lowered into the casing 1. When the packer is in the setting process, the micro-deformation adjustment mechanism 5 is in an expanded state, and the expansion achieves an interference seal with the inner wall of the casing 1, separating different layers of the oil and gas well and facilitating low-carbon oil extraction.

[0042] It should be noted that the casing 1 is coaxially assembled from top to bottom along the axial direction with the tubing 2, the packer housing 3, and the packer center tube 4. The tubing 2 is located in the upper part of the inner side of the casing 1, and its lower end is coaxially connected with the top of the packer center tube 4, forming the main channel for downhole fluid transmission. The packer housing 3 is correspondingly arranged in the middle part of the inner side of the casing 1, and is coaxially sleeved on the outside of the packer center tube 4 with the packer center tube 4 as the axis, forming a double-layer nested structure to provide spatial support.

[0043] Please refer to Figure 1 - Figure 10 As shown, the micro-deformation adjustment mechanism 5 includes a rubber sleeve assembly 51. The rubber sleeve assembly 51 is coaxially mounted on the outer periphery of the packer housing 3, forming a radial linkage structure with the housing. The rubber sleeve assembly 51 adopts a multi-segment combination design, and its whole is composed of no less than three cylindrical rubber sleeves connected in series along the axial direction. The adaptability to irregular wellbores is improved by the coordinated deformation of multiple rubber sleeves. Each cylindrical rubber sleeve is symmetrically equipped with a shrinking and expanding ring 52 at both the upper and lower ends. In the rubber sleeve assembly 51, the shrinking and expanding ring 52 located above the cylindrical rubber sleeve has a funnel-shaped structure with an axial cross section that is narrow at the top and wide at the bottom. Its small diameter end faces upward and its large diameter end is adapted and connected to the top of the cylindrical rubber sleeve. The shrinking and expanding ring 52 located below the cylindrical rubber sleeve has a funnel-shaped structure with an axial cross section that is wide at the top and narrow at the bottom. Its large diameter end faces upward and is adapted and connected to the bottom of the cylindrical rubber sleeve, while its small diameter end is set downward.

[0044] It should be noted that when the equipment is in the installation and lowering process, the expansion and contraction rings 52 are all in a contracted state, and the diameter of the output port of the expansion and contraction rings 52 is smaller than the diameter of the cylindrical rubber tube in the rubber tube assembly 51, ensuring that the packer as a whole passes smoothly through the internal space of the sleeve 1. When the equipment is in the setting and sealing process, the expansion and contraction rings 52 are all in an expanded state, and the diameter of the output port of the expansion and contraction rings 52 is consistent with the diameter of the cylindrical rubber tube in the rubber tube assembly 51. By matching the diameter of the expansion and contraction rings 52 with that of the cylindrical rubber tube, the integrity of the sealing surface and the reliability of the fit are ensured.

[0045] It should be noted that each adjacent expansion and contraction ring 52 is coaxially fitted with a spacer ring 53. A ring-shaped limiting buckle 54 is fixedly connected to the inner wall of the spacer ring 53. Movable protrusions 55 are evenly distributed along the circumferential direction on the outer circumferential surface of the limiting buckle 54, and the movable protrusions 55 are slidably connected to the limiting buckle 54. The upper end of each movable protrusion 55 is fixedly connected to the lower end of the upper expansion and contraction ring 52, and the lower end of each movable protrusion 55 is fixedly connected to the upper end of the lower expansion and contraction ring 52, forming a connection between the expansion and contraction ring 52 and the spacer ring 53. The moving structure has circular arc grooves 56 on the radial outer side walls of each movable protrusion 55. Elastic connecting cables 57 are installed in the circular arc grooves 56. Several movable protrusions 55 form a circumferentially closed integrated linkage structure through the elastic connecting cables 57. The elastic connecting cables 57 pass through each circular arc groove 56 along the circumferential direction of the movable protrusions 55. The outer wall of the elastic connecting cables 57 is uniformly fixedly connected with dividing cylinders 58. Each dividing cylinder 58 is correspondingly embedded in the center gap between two adjacent movable protrusions 55, forming a circumferentially distributed interval positioning structure of the movable protrusions 55.

[0046] Please refer to Figure 4 - Figure 7 As shown, rigid retaining rings 59 are symmetrically mounted at the upper and lower ends of the rubber sleeve assembly 51. The rigid retaining rings 59 are all attached to the inner wall of the sleeve 1, and the rigid retaining rings 59 are all made of boron nitride material. A connecting ring 510 is installed inside the rigid retaining ring 59. An elastic interlayer 511 is installed on the side of the connecting ring 510 away from the rigid retaining ring 59. The connecting ring 510 is composed of several inclined pieces, and each inclined piece is made of shape memory alloy material.

[0047] It should be noted that there are many bonds between atoms or ions in the crystal structure of boron nitride ceramics. The bonding force between atoms or ions in boron nitride ceramic materials is relatively strong, which enables boron nitride ceramic materials to effectively transfer heat energy.

[0048] It should be noted that the tilting plates are all made of shape memory alloy, specifically nickel-titanium shape memory alloy. Nickel-titanium shape memory alloy is mainly composed of nickel and titanium, with the nickel content ranging from about 49% to 51% (atomic percentage), and the titanium (Ti) content also controlled at around 49% to 51% (atomic percentage). When it is subjected to heat input, the molecules will absorb this heat energy and convert it into molecular thermal motion. Molecular thermal motion will weaken the interaction force between molecules and change the equilibrium position between molecules, thereby causing the volume of the material to increase, i.e., thermal expansion. When the temperature drops, it can return to its original shape.

[0049] Specifically, the working status and operational flow of each component in the micro-deformation adjustment mechanism 5 are as follows: Working status and operational flow of the micro-deformation adjustment mechanism 5 during packer installation:

[0050] During the packer installation and lowering phase, the micro-deformation adjustment mechanism 5 is in a retracted state, with all components working together to reduce lowering resistance and ensure the entire assembly smoothly passes through the internal space of the sleeve 1. Figure 3 and Figure 4 As shown, specifically, the multi-segment cylindrical rubber tube of the rubber tube assembly 51 maintains its initial contracted shape, and the expansion and contraction rings 52 at its upper and lower ends are simultaneously in a contracted state. At this time, in the funnel-shaped structure of the upper expansion and contraction ring 52, which is narrower at the top and wider at the bottom, the output port diameter is smaller than the diameter of the cylindrical rubber tube, and the output port diameter of the funnel-shaped structure of the lower expansion and contraction ring 52, which is wider at the top and narrower at the bottom, is also smaller than the diameter of the rubber tube, forming a streamlined structure with "narrowing at both ends" to avoid rubbing against the inner wall of the sleeve 1.

[0051] Meanwhile, the limiting buckle 54 inside the spacer 53 constrains the moving protrusion 55 to a radially contracted position. The moving protrusion 55 is kept in a circumferentially tightened state by the elastic connecting cable 57 in the arc groove 56. The separating cylinder 58 on the elastic connecting cable 57 stabilizes the gap between adjacent moving protrusions 55, preventing them from shifting due to shaking during descent. The rigid retaining rings 59 at the upper and lower ends of the rubber sleeve assembly 51 are not subjected to external force and remain coaxially attached to the packer housing 3. The contracted state of the above components forms a compact structure, ensuring that the packer descends smoothly to the target layer in the sleeve 1, laying the foundation for subsequent setting operations.

[0052] Working status and function flow of the micro-deformation adjustment mechanism 5 during packer setting:

[0053] When the packer enters the setting stage, all components of the micro-deformation adjustment mechanism 5 synchronously switch to the expansion state, achieving an interference seal with the inner wall of the casing 1 through coordinated action, such as... Figure 8 and Figure 9 As shown, the specific process is as follows: External pressure (such as hydraulic or mechanical force) is transmitted to the packer housing 3 through the channel between the oil pipe 2 and the packer central tube 4, pushing the multi-section cylindrical rubber tube of the rubber tube assembly 51 to expand radially. At this time, the upper and lower expansion rings 52 expand synchronously under the expansion force of the rubber tube. The upper expansion ring 52's narrow upper and wide lower structure guides the upper end of the rubber tube to extend outward evenly, while the lower expansion ring 52's wide upper and narrow lower structure constrains the expansion direction of the lower end of the rubber tube. Finally, the output diameter of the expansion ring 52 is consistent with the diameter of the cylindrical rubber tube, ensuring that the rubber tube and the inner wall of the sleeve 1 form a continuous and complete sealing surface.

[0054] During this process, the movable protrusion 55 slides radially along the outer peripheral surface of the limiting ring 54, and the elastic connecting cable 57 stretches as the movable protrusion 55 unfolds. The separating cylinder 58 on its outer wall maintains a uniform spacing between adjacent protrusions, avoiding excessive local expansion of the rubber sleeve. The coordinated deformation of multiple cylindrical rubber sleeves can adapt to the irregular shape of the inner wall of the pipe 1 (such as local concavity and convexity). Through segmented compensation, the sealing pressure is ensured to be evenly distributed, effectively separating different layers of the oil and gas well, reducing interlayer fluid flow, reducing ineffective extraction energy consumption, and achieving the goal of low-carbon extraction.

[0055] The process and function of heat absorption and heat transfer from the rigid retaining ring 59 to the integral ring 510:

[0056] During the operation after the packer is set, the hard retaining ring 59 and the integrated ring 510 enhance the sealing stability through a heat transfer mechanism. Specifically, the hard retaining ring 59 is made of boron nitride, and its strongly bonded crystal structure has excellent thermal conductivity, which can quickly absorb heat from the downhole environment (such as formation conduction heat and fluid friction heat). The absorbed heat is transferred to the integrated ring 510 through the contact interface between the hard retaining ring 59 and the integrated ring 510. The integrated ring 510 is composed of inclined plates of nickel-titanium shape memory alloy. When heat is input, the nickel-titanium alloy molecules absorb heat energy and convert it into molecular thermal motion, which causes the material volume to expand, causing the inclined plates to open outward and compress the elastic interlayer 511.

[0057] When the elastic interlayer 511 is subjected to force, it reacts to the connecting ring 510, further pushing the hard retaining ring 59 to fit tightly against the inner wall of the casing 1. This compensates for the sealing gap caused by temperature changes or long-term use, enhancing the sealing reliability of the packer. At the same time, when the downhole temperature decreases, the nickel-titanium shape memory alloy inclined plate returns to its initial shape, preventing the hard retaining ring 59 from excessively squeezing the casing 1 and causing damage. This achieves dynamic sealing adjustment of "thermal expansion compensation and cold contraction reset", extending the service life of the packer, reducing the frequency of well workover, and indirectly reducing carbon emissions during the extraction process.

[0058] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A compression-type external packer based on low-carbon oil extraction, comprising a casing (1), characterized in that: The casing (1) is equipped with a micro-deformation adjustment mechanism (5). When the packer is in the installation process, the micro-deformation adjustment mechanism (5) is in a contracted state to ensure that the packer can be smoothly lowered into the casing (1). When the packer is in the setting process, the micro-deformation adjustment mechanism (5) is in an expanded state. Through expansion, it achieves an interference seal with the inner wall of the casing (1), separates different layers of the oil and gas well, and helps low-carbon oil extraction. The micro-deformation adjustment mechanism (5) includes a rubber tube assembly (51). The rubber tube assembly (51) is coaxially mounted on the outer periphery of the packer housing (3) to form a radial linkage structure with the housing. The rubber tube assembly (51) adopts a multi-segment combination design. Its whole is composed of no less than three cylindrical rubber tubes connected in series along the axial direction. The adaptability to irregular wellbores is improved by the coordinated deformation of the multi-segment rubber tubes. Each cylindrical rubber tube is symmetrically equipped with a shrinking and expanding ring (52) at both the upper and lower ends. Each of the adjacent expansion and contraction openings (52) is coaxially fitted with a spacer ring (53). The inner wall of the spacer ring (53) is fixedly connected with a ring-shaped limiting buckle (54). The outer circumferential surface of the limiting buckle (54) is evenly distributed with movable protrusions (55) along the circumferential direction. The movable protrusions (55) and the limiting buckle (54) are slidably connected. The upper end of each movable protrusion (55) is fixedly connected to the lower end of the upper expansion and contraction opening (52), and the lower end of the movable protrusion (55) is fixedly connected to the upper end of the lower expansion and contraction opening (52), forming a linkage structure between the expansion and contraction opening (52) and the spacer ring (53). The radial outer sidewall of each movable protrusion (55) is provided with an arc groove (56), and an elastic connecting cable (57) is assembled in the arc groove (56). Several movable protrusions (55) form a circumferentially closed integrated linkage structure through the elastic connecting cable (57). The elastic connecting cable (57) passes through each arc groove (56) along the circumferential direction of the movable protrusion (55), and the outer wall of the elastic connecting cable (57) is uniformly fixedly connected with a dividing cylinder (58). Each dividing cylinder (58) is correspondingly embedded in the center gap between two adjacent movable protrusions (55), forming a circumferentially distributed interval positioning structure of the movable protrusions (55).

2. The compression-type external packer based on low-carbon oil extraction according to claim 1, characterized in that: The casing (1) is coaxially assembled with an oil pipe (2), a packer outer shell (3) and a packer center tube (4) from top to bottom along the axial direction. The oil pipe (2) is located in the upper part of the inner side of the casing (1), and its lower end is coaxially connected with the top of the packer center tube (4) to form the main channel for downhole fluid transmission. The packer outer shell (3) is arranged in the middle part of the inner side of the casing (1), and is coaxially sleeved on the outside of the packer center tube (4) with the packer center tube (4) as the axis, forming a double-layer nested structure to provide spatial support.

3. A compression-type external packer based on low-carbon oil extraction according to claim 1, characterized in that: In the rubber tube assembly (51), the expansion and contraction opening (52) located above the cylindrical rubber tube has a funnel-shaped structure with an axial cross-section that is narrower at the top and wider at the bottom. Its small diameter end faces upward, and its large diameter end is adapted to and connected to the top of the cylindrical rubber tube. The expansion and contraction opening (52) located below the cylindrical rubber tube has a funnel-shaped structure with an axial cross-section that is wider at the top and narrower at the bottom. Its large diameter end faces upward and is adapted to and connected to the bottom of the cylindrical rubber tube, while its small diameter end faces downward.

4. A compression-type external packer based on low-carbon oil extraction according to claim 1, characterized in that: When the equipment is in the installation and lowering process, the expansion and contraction rings (52) are all in a contracted state. The diameter of the output port of the expansion and contraction rings (52) is smaller than the diameter of the cylindrical rubber tube in the rubber tube assembly (51), ensuring that the packer as a whole passes smoothly through the internal space of the sleeve (1).

5. A compression-type external packer based on low-carbon oil extraction according to claim 1, characterized in that: When the equipment is in the setting and sealing process, the expansion and contraction rings (52) are all in an expanded state. The diameter of the outlet of the expansion and contraction rings (52) is consistent with the diameter of the cylindrical rubber tube in the rubber tube assembly (51). By matching the diameter of the expansion and contraction rings (52) with the cylindrical rubber tube, the integrity of the sealing surface and the reliability of the fit are ensured.

6. A compression-type external packer based on low-carbon oil extraction according to claim 1, characterized in that: The upper and lower ends of the rubber sleeve assembly (51) are symmetrically equipped with hard retaining rings (59). The hard retaining rings (59) are all attached to the inner wall of the sleeve (1), and the hard retaining rings (59) are all made of boron nitride material.

7. A compression-type external packer based on low-carbon oil extraction according to claim 6, characterized in that: The internal components of the rigid retaining ring (59) are all equipped with integrated ring components (510). An elastic interlayer (511) is installed on the side of the integrated ring component (510) away from the rigid retaining ring (59). The integrated ring component (510) is composed of several inclined pieces, each of which is made of shape memory alloy.

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