An underwater packer with high sealing reliability

Abstract

This invention relates to the field of oil well equipment technology, specifically disclosing a highly reliable underwater packer, comprising: a packer body, a differential pressure sensing chamber, a first connecting hole, a second connecting hole, and a receiving groove. The differential pressure sensing chamber is located in the middle of the outer wall of the packer body. The first connecting hole, communicating with the inner cavity of the differential pressure sensing chamber, is located at the rear ends of both the upper and lower sides of the outer wall of the packer body. The second connecting hole, communicating with the inner cavity of the differential pressure sensing chamber, is located at the front ends of both the upper and lower sides of the outer wall of the packer body. The receiving groove is located in the middle of the outer wall of the packer body. This device features a double-layer sealing structure to improve the long-term sealing reliability in deep water. Combined with dual independent magnetic sensors, it achieves accurate identification of the sealing setting and online early warning of leaks, overcoming the shortcomings of traditional packers with single-layer seals that are easily damaged, have large errors in construction judgment, and are slow to detect leaks. This significantly improves the controllability of deep-sea oil and gas stratified extraction and the safety of downhole operations.

Description

Technical Field

[0001] This invention relates to the field of oil well equipment technology, specifically to a highly reliable underwater packer. Background Technology

[0002] In offshore oil and gas development projects, subsea packers are core downhole tools for stratified extraction, stratified water injection, and downhole isolation operations. They mainly rely on the radial expansion of sealing elements to fit against the inner wall of the well casing, effectively separating fluids from different formations to avoid inter-layer crossflow and improve oil and gas recovery efficiency. Deepwater oil and gas wells operate in harsh environments characterized by high pressure, high corrosion, media containing solid particles, and long-term alternating pressure differentials. Therefore, stringent requirements are placed on the sealing durability and downhole condition real-time monitoring capabilities of subsea packers. Currently, conventional subsea packers in the industry mainly rely on a single rubber sleeve as the sealing core. During construction, the rubber sleeve is set and sealed by axial load of the tubing string. The matching slip structure achieves downhole anchoring and fixation. The degree of rubber sleeve setting is roughly judged by the pressure stroke of the surface tubing string, which meets the basic stratified isolation requirements of conventional shallow water and low-pressure oil and gas wells. However, under deep water, high pressure, and long-term service conditions, existing traditional packers have exposed many unavoidable technical defects. First, traditional subsea packers use only a single-layer rubber sleeve as the sole sealing barrier structure, without any auxiliary sealing and protection structures. In deep water environments, the fluid produced in the wellbore carries mud, sand, and rock cuttings, which continuously rub against the outer wall of the rubber sleeve. At the same time, the formation corrosive media and long-term reciprocating high pressure differential loads can easily cause the rubber sleeve to age, crack, and suffer local damage. Once a small leakage defect occurs in the rubber sleeve, the high-pressure fluids in the upper and lower formations will directly flow between the layers, destroying the layered production system. This can lead to a decrease in oil and gas production and failure of water injection and regulation, or even cause wellbore pressure imbalance and bring downhole safety hazards. The single-layer sealing structure has an extremely low fault tolerance rate, and the sealing reliability is difficult to adapt to the harsh service environment in deep water. Secondly, existing packers cannot accurately and intuitively provide feedback to the surface on the setting status of the rubber sleeve. During construction, the setting completion status is indirectly judged only by the pump pressure value. There is a lack of in-situ downhole signal acquisition devices. The pressure collected from the surface is subject to interference from factors such as well casing deformation, tubing friction, and downhole impurities. This can easily lead to two construction problems: under-sealing or over-pressure squeezing. Under-sealing, the rubber sleeve does not expand enough and cannot form an effective seal against the inner wall of the casing. Interlayer leakage occurs directly after it is run in. Over-pressure squeezing will exceed the deformation limit of the rubber sleeve material, causing irreversible tearing damage to the rubber sleeve, which will significantly shorten the downhole service life. Moreover, the construction personnel cannot confirm in real time whether the sealing element has fully expanded and adhered to the casing. The construction quality depends entirely on the experience of the operators, resulting in poor construction controllability. Furthermore, conventional subsea packers do not have real-time online monitoring and early warning functions for interlayer leakage. After the sealing structure has been put into long-term production downhole, the surface control system cannot obtain the downhole sealing integrity status in real time. It can only rely on the changes in the composition of the produced fluid and the wellhead pressure to infer whether there is interlayer leakage. This detection method has a strong lag. When abnormal production data is detected by the surface, the downhole rubber sleeve is damaged and the interlayer flow problem has been going on for a long time. This not only causes a lot of oil and gas resources to be wasted, but long-term formation fluid flow will also damage the reservoir geological structure and increase the difficulty and cost of subsequent well workover operations. In summary, existing underwater packers have low fault tolerance due to their single-layer sealing structure, insufficient sealing durability under deep-water and high-pressure conditions, inability to accurately provide in-situ feedback on the setting status, difficulty in controlling construction quality, and delayed detection of leaks. They are unable to meet the actual engineering needs of efficient, safe, and long-term stratified exploitation of deep-sea oil and gas. Summary of the Invention

[0003] The purpose of this invention is to provide a highly reliable underwater packer that can at least solve the problems of low single-layer seal tolerance, inaccurate feedback of setting status, and delayed early warning of leakage faults in the prior art.

[0004] To achieve the above objectives, the present invention provides the following technical solution: a highly reliable underwater packer, comprising: a packer body, a differential pressure sensing chamber, a first communicating hole, a second communicating hole, a receiving groove, an air vent, an indicating mechanism, a monitoring mechanism, a connecting ring, a rubber sleeve, a conical block, a slip component, and a central tube. The differential pressure sensing chamber is located in the middle of the outer wall of the packer body. The upper and lower rear ends of the outer wall of the packer body are each provided with a first communicating hole communicating with the inner cavity of the differential pressure sensing chamber. The upper and lower front ends of the outer wall of the packer body are each provided with a second communicating hole communicating with the inner cavity of the differential pressure sensing chamber. A receiving groove is located in the middle of the outer wall of the packer body, and the inner wall of the receiving groove is equidistantly spaced along the circumferential direction. The packer body has several vents communicating with its inner cavity. The second connecting hole is located at the front of the receiving slot, and the first connecting hole is located at the rear of the receiving slot. The indicating mechanism is located at the front end of the packer body, the monitoring mechanism is located in the inner cavity of the differential pressure sensing chamber, the connecting ring is located at the front end of the indicating mechanism, the rubber sleeve is located at the front end of the connecting ring, the cone block is located at the front end of the rubber sleeve, and the rear side of the outer wall of the central tube is located in the inner cavity of the packer body. The front end of the central tube slidably passes through the inner cavities of the indicating mechanism, the connecting ring, the rubber sleeve, and the cone block. The slip component is slidably and appropriately matched to the front end of the outer wall of the central tube. The slip component and the cone block are in contact and are matched.

[0005] Preferably, the indicating mechanism includes: a rotating cylinder, a spiral groove, a first permanent magnet, and a Hall sensor. The rear end of the rotating cylinder is rotatably disposed at the front end of the packer body via a bearing, and the front end of the rotating cylinder is rotatably disposed at the rear side of the connecting ring via a bearing. Two spiral grooves are equidistantly formed on the inner wall of the rotating cylinder along the circumference. The first permanent magnet is disposed at the bottom rear end of the rotating cylinder, and the Hall sensor is disposed at the top front end of the packer body. The Hall sensor and the first permanent magnet are symmetrical about the axis of the central tube.

[0006] Preferably, the included angle between the front and rear ends of the spiral groove is 180 degrees.

[0007] Preferably, the monitoring mechanism includes: a sleeve, a first piston, a rubber airbag, a sleeve, and an alarm component. The sleeve is disposed at the middle of the rear end of the cone block. The central tube is slidably fitted into the inner cavity of the sleeve. The outer wall of the sleeve is slidably fitted into the inner cavity of the connecting ring. The rear end of the sleeve slidably extends into the front side of the inner cavity of the packer body. The first piston is disposed at the rear end of the sleeve. The first piston is slidably fitted into the inner cavity of the packer body. The first piston is slidably fitted into the outer wall of the central tube. The rubber airbag is disposed in the inner cavity of the receiving groove. The inner cavity of the rubber airbag is connected to the inner cavity of the air hole. The sleeve is fitted onto the outer wall of the differential pressure sensing cavity. The alarm component is disposed in the inner cavity of the differential pressure sensing cavity.

[0008] Preferably, the alarm assembly includes: a second piston, a limiting cylinder, a second permanent magnet, a spring, and an annular Hall sensor. The second piston is slidably fitted to the inner wall of the differential pressure sensing chamber and slidably fitted into the inner cavity of the sleeve. The limiting cylinder is located on the rear side of the second piston and is slidably fitted to the inner wall of the differential pressure sensing chamber. The second permanent magnet is located at the rear end of the limiting cylinder. The spring is sleeved on the inner wall of the differential pressure sensing chamber, with one end of the spring engaged with the rear side of the second piston and the other end engaged with the rear side of the inner cavity of the differential pressure sensing chamber. The annular Hall sensor is located on the rear side of the inner cavity of the differential pressure sensing chamber, and the position of the annular Hall sensor corresponds to the position of the second permanent magnet.

[0009] Preferably, the outer wall of the sleeve is provided with two drive posts at equal intervals along the circumference, and the two drive posts are respectively slidably adapted to be inserted into the front side of the inner cavity of the two spiral grooves.

[0010] Preferably, multiple sets of air holes are evenly distributed along the circumference of the receiving groove. When the air in the inner cavity of the packer body is continuously filled into the inner cavity of the rubber air bag through the air holes by the first piston, the rubber air bag can be radially outward to fit against the inner wall of the oil well casing to form an annular auxiliary sealing layer, which together with the rubber sleeve constitutes a double-layer sealing barrier structure.

[0011] Preferably, the Hall sensor and the ring Hall sensor form a dual-channel magnetic sensing monitoring system. The Hall sensor collects the rotation signal of the rotating cylinder to determine the completion status of the rubber cylinder setting, and the ring Hall sensor collects the displacement signal of the second permanent magnet to determine the interlayer pressure difference leakage status. The two sensing signals are collected independently and transmitted to the ground synchronously through wired cables.

[0012] The underwater packer with high sealing reliability proposed in this invention has the following advantages: 1. This invention involves lowering the entire packer along with the tubing string to the target formation in the well. Throughout the lowering process, the slip components, rubber sleeve, and rubber airbag are all in a contracted and closed state. The slips fit against the outer wall of the central tube without contacting the inner wall of the casing, effectively preventing the slip teeth from scratching the well casing during the lowering process and protecting the well casing structure.

[0013] 2. This invention uses a ground winch to lift and lower the tubing column, driving the conical block to compress the slip component radially, so that the slip teeth bite into the inner wall of the sleeve and complete the anchoring and locking, providing stable rigid support for subsequent sealing compression, preventing the packer from shifting as a whole during setting, and ensuring the quality of the seal formation.

[0014] 3. This invention pushes the packer body through the central tube to squeeze the rubber cylinder. The rubber cylinder expands radially under pressure and adheres to the inner wall of the oil well casing to form the main sealing layer, which directly separates the upper and lower formation fluids, thereby achieving layered mining and blocking conventional inter-layer flow.

[0015] 4. The present invention generates axial relative displacement between the packer body and the sleeve. The first piston squeezes the air in the inner cavity to fill the rubber airbag and expand it to form an auxiliary sealing layer. Together with the rubber sleeve, it forms a double-layer sealing barrier structure, which improves the sealing fault tolerance and resists the risk of seal damage caused by mud and sand abrasion and media corrosion. It is suitable for harsh working conditions of deep water and high pressure.

[0016] 5. The present invention uses the drive column on the outer wall of the casing to slide along the 180° spiral groove inside the rotating cylinder, which converts the axial displacement of the casing into a 180° circumferential rotation of the rotating cylinder. The first permanent magnet, together with the Hall sensor, transmits the electrical signal of the sealing completion to the ground. The actual sealing status is collected in situ downhole, eliminating the error of relying on pump pressure to judge, and avoiding under-sealing failure or over-pressure tearing of the rubber sleeve.

[0017] 6. During normal production with a good seal, the pressure in the annulus interlayer is consistent with that in the wellbore behind the packer, the pressure before and after the differential pressure sensing chamber is balanced, the alarm component has no signal output, and the seal condition can be continuously and uninterruptedly monitored without the need for real-time manual intervention.

[0018] 7. When the rubber sleeve is damaged and leaks, the high-pressure ground fluid rushes into the annular space between the rubber sleeve and the air bladder. A significant pressure difference is formed before and after the differential pressure sensing chamber, which pushes the second piston to move backward. This can quickly detect abnormal sealing and leakage, and there will be no problem of fault monitoring lag.

[0019] 8. This invention uses a second piston to move a second permanent magnet to the sensing range of an annular Hall sensor. The sensor transmits an alarm signal to the ground terminal in real time, which can immediately alert to downhole sealing failure, reduce oil and gas loss, prevent reservoir damage from crossflow, and reduce subsequent well repair costs.

[0020] 9. This device features a double-layer sealing structure to enhance the reliability of long-term sealing in deep water. It is equipped with dual independent magnetic sensors to achieve accurate identification of the sealing and online early warning of leaks. This overcomes the shortcomings of traditional packers, such as easy damage to single-layer seals, large errors in construction judgment, and delayed detection of leaks. It significantly improves the controllability of construction and the safety of downhole operations in deep-sea oil and gas stratification exploitation. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a right-side cross-sectional view of the present invention; Figure 3 This is an exploded view of the present invention; Figure 4 This is a schematic diagram of the structure of a ring Hall sensor; Figure 5 for Figure 4 Enlarged view of point A; Figure 6 for Figure 4 Enlarged view of point B; Figure 7 for Figure 4 Enlarged view of point C.

[0022] In the diagram: 1. Packer body; 2. Differential pressure sensing chamber; 3. First connecting hole; 4. Second connecting hole; 5. Storage groove; 6. Air hole; 7. Indicating mechanism; 71. Rotating cylinder; 72. Spiral groove; 73. First permanent magnet; 74. Hall sensor; 75. Drive column; 8. Monitoring mechanism; 81. Sleeve; 82. First piston; 83. Rubber airbag; 84. Sleeve; 85. Alarm assembly; 851. Second piston; 852. Limiting cylinder; 853. Second permanent magnet; 854. Spring; 855. Annular Hall sensor; 9. Connecting ring; 10. Rubber sleeve; 11. Conical block; 12. Slip component; 13. Central tube. Detailed Implementation

[0023] 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 skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] Please see Figures 1-7 This invention provides a high-sealing-reliability underwater packer technical solution, comprising: a packer body 1, a differential pressure sensing chamber 2, a first connecting hole 3, a second connecting hole 4, a storage groove 5, an air vent 6, an indicating mechanism 7, a monitoring mechanism 8, a connecting ring 9, a rubber sleeve 10, a cone block 11, a slip component 12, and a central tube 13. The differential pressure sensing chamber 2 is located in the middle of the outer wall of the packer body 1. The upper and lower rear ends of the outer wall of the packer body 1 are each provided with a first connecting hole 3 communicating with the inner cavity of the differential pressure sensing chamber 2. The upper and lower front ends of the outer wall of the packer body 1 are each provided with a second connecting hole 4 communicating with the inner cavity of the differential pressure sensing chamber 2. The storage groove 5 is located in the middle of the outer wall of the packer body 1. The inner wall of the storage groove 5 is circumferentially... A number of equidistant air holes 6 communicating with the inner cavity of the packer body 1 are provided. The second connecting hole 4 is located on the front side of the receiving groove 5, and the first connecting hole 3 is located on the rear side of the receiving groove 5. The packer body 1 is the overall supporting base of this device. The indicating mechanism 7 is set at the front end of the packer body 1. The indicating mechanism 7 is used to convert the axial displacement of the sleeve 81 into rotational motion and to feed back the sealing status of the rubber sleeve 10 to the ground through magnetic signals, thereby eliminating construction judgment errors. The monitoring mechanism 8 is set in the inner cavity of the differential pressure sensing chamber 2. The monitoring mechanism 8 integrates a piston inflation structure and a differential pressure alarm component. On the one hand, it drives the rubber airbag 83 to form an auxiliary seal, and on the other hand, it monitors the interlayer pressure difference in real time. If the seal is damaged, it outputs a leakage alarm signal. The connecting ring 9 is located at the front end of the indicating mechanism 7. The connecting ring 9 is used to transmit the axial compressive force of the packer body 1, evenly distribute the load to the end face of the rubber sleeve 10, and ensure that the rubber sleeve expands radially evenly. The rubber sleeve 10 is located at the front end of the connecting ring 9. The rubber sleeve 10 is the main sealing element of the device. After being axially compressed, it expands radially to fit the inner wall of the well casing, forming the first sealing barrier to isolate the upper and lower formation fluids. The cone block 11 is located at the front end of the rubber sleeve 10. The cone block 11 is a cone-shaped structural component. On the one hand, it cooperates with the slip component 12 to achieve downhole anchoring. On the other hand, it fixes the casing 81 and remains stationary during setting. It generates relative displacement with the packer body 1 to complete the inflation of the airbag. The outer wall of the central tube 13 is located on the rear side of the packer body 1. The inner cavity of the central tube 13 is slidably slidably through the inner cavity of the indicator mechanism 7, the connecting ring 9, the rubber sleeve 10, and the cone block 11. The central tube 13 is the core rod for axial force transmission, connecting to the surface tubing string, transmitting lifting and pushing loads, and penetrating all internal components. It provides an axial sliding track for the slip component 12 and the casing 81. The slip component 12 is slidably and appropriately matched to the front end of the outer wall of the central tube 13. The slip component 12 and the cone block 11 are in contact and matched. The slip component 12 is existing technology and will not be described in detail here. The slip component 12 is a downhole anchoring component. After being squeezed by the inclined surface of the cone block 11, it opens radially and the hard teeth bite into the inner wall of the casing to lock the whole machine, providing a stable support reference for the compression seal of the rubber sleeve 10.

[0025] As a preferred embodiment, the monitoring mechanism 8 further includes: a sleeve 81, a first piston 82, a rubber airbag 83, a sleeve 84, and an alarm component 85. The sleeve 81 is located at the middle of the rear end of the cone block 11. The central tube 13 is slidably and compatiblely inserted into the inner cavity of the sleeve 81. The outer wall of the sleeve 81 is slidably and compatiblely inserted into the inner cavity of the connecting ring 9. The rear end of the sleeve 81 slidably extends into the front side of the inner cavity of the packer body 1. The sleeve 81 remains axially stationary synchronously with the cone block 11. The outer wall is equipped with a drive column 75 and a linkage indicator mechanism 7. The rear end drives the first piston 82 to slide synchronously, realizing the air compression supply to the inner cavity. The first piston 82 is located at the rear end of the sleeve 81. The first piston 82 is slidably and compatiblely inserted into the inner cavity of the packer body 1. The first piston 82 is slidably and compatiblely inserted into the outer wall of the central tube 13. The first piston 82 can slide along the inner cavity of the packer body 1. During sealing, the air inside the main body is compressed and pushed backward. High-pressure gas is sent into the rubber airbag 83 through the air hole 6 to provide pneumatic power for auxiliary sealing. The rubber airbag 83 is set in the inner cavity of the receiving groove 5. The inner cavity of the rubber airbag 83 is connected to the inner cavity of the air hole 6. The rubber airbag 83 is used to receive the compressed air squeezed by the first piston 82 and then expand radially to fit against the inner wall of the oil well casing. It is combined with the rubber sleeve 10 to form a double-layer sealing structure, which improves the sealing fault tolerance. The sleeve 84 is fitted onto the outer wall of the differential pressure sensing cavity 2. The sleeve 84 plays a protective and limiting role for the alarm component 85 in the cavity, isolates impurities in the well fluid, and ensures the stable sliding operation of the internal piston, magnet, and sensor. The alarm component 85 is set in the inner cavity of the differential pressure sensing cavity 2. The alarm component 85 generates a magnetic sensing signal driven by the pressure difference between the interlayer and the rear well barrel, identifies the leakage fault of the rubber sleeve 10 in real time, and outputs an alarm prompt to the ground to realize online monitoring of sealing integrity.

[0026] As a preferred embodiment, the alarm assembly 85 further includes: a second piston 851, a limiting cylinder 852, a second permanent magnet 853, a spring 854, and a ring-shaped Hall sensor 855. The second piston 851 is slidably and appropriately fitted to the inner wall of the differential pressure sensing chamber 2, and slidably and appropriately inserted into the inner cavity of the sleeve 84. The second piston 851 is used to bear the pressure difference of the fluid before and after the chamber. When the pressure difference exceeds the limit, it slides backward, driving the rear end component to move synchronously. It is the mechanical conversion carrier of the differential pressure signal. The limiting cylinder 852 is located on the rear side of the second piston 851 and is slidably and appropriately fitted to the inner wall of the differential pressure sensing chamber 2. The limiting cylinder 852 is used to move axially synchronously with the second piston 851, to support the second permanent magnet 853, and at the same time to limit the sliding deviation of the second piston 851, ensuring accurate alignment between the magnet and the sensor. The second permanent magnet 853 is located at the rear end of the limiting cylinder 852. The second permanent magnet 853 is used to follow the piston assembly backward and move closer to the ring-shaped Hall sensor. The Hall sensor 855 changes the local magnetic field to provide a magnetic field sensing source for leak detection. A spring 854 is sleeved on the inner wall of the differential pressure sensing cavity 2. One end of the spring 854 is engaged with the rear side of the second piston 851, and the other end is engaged with the rear side of the inner cavity of the differential pressure sensing cavity 2. The spring 854 is a rotary spring; it undergoes elastic deformation after being compressed or stretched by external force and returns to its initial state after the external force is removed. When the seal is intact, the spring 854 maintains the second piston 851 in a pre-reset state. When a differential pressure occurs, it is compressed by the second piston 851. After the differential pressure disappears, it pushes the second piston 851 to reset. The annular Hall sensor 855 is located on the rear side of the inner cavity of the differential pressure sensing cavity 2. The position of the annular Hall sensor 855 corresponds to the position of the second permanent magnet 853. The annular Hall sensor 855 is existing technology and will not be described in detail here. When the second permanent magnet 853 approaches, the annular Hall sensor 855 can sense the magnetic field and generate an electrical signal that is transmitted to the ground, thus realizing a leak alarm.

[0027] As a preferred embodiment, the indicating mechanism 7 further includes: a rotating cylinder 71, spiral grooves 72, a first permanent magnet 73, a Hall sensor 74, and a drive column 75. The rear end of the rotating cylinder 71 is rotatably mounted on the front end of the packer body 1 via a bearing, and the front end of the rotating cylinder 71 is rotatably mounted on the rear side of the connecting ring 9 via a bearing. Two spiral grooves 72 are equidistantly spaced along the circumference of the inner wall of the rotating cylinder 71, with an included angle of 180 degrees between the front and rear ends of the spiral grooves 72. The rotating cylinder 71, in conjunction with the drive column 75, can convert the linear axial movement of the sleeve 81 into its own circumferential rotation, synchronously rotating with the first permanent magnet 73. The first permanent magnet 73 is located at the rear bottom end of the rotating cylinder 71 and is used to rotate synchronously with the rotating cylinder 71. Once in position, it faces the Hall sensor 74 and generates a captureable magnetic field change signal, which serves as the magnetic source for induction of sealing completion. The Hall sensor 74 is located on the top front side of the packer body 1. The Hall sensor 74 and the first permanent magnet 73 are symmetrical about the axis of the central tube 13. The Hall sensor 74 is existing technology and will not be described in detail here. The Hall sensor 74 can sense the change in the magnetic field of the permanent magnet and generate an electrical signal to be transmitted to the ground, thereby determining the sealing completion status of the rubber sleeve 10. There are two drive columns 75. The two drive columns 75 are equidistantly arranged on the outer wall of the sleeve 81 along the circumference. The two drive columns 75 are slidably adapted to be inserted into the front side of the inner cavity of the two spiral grooves 72. The drive columns 75 are used to realize the power conversion from linear motion to rotational motion.

[0028] As a preferred option, furthermore, multiple sets of air holes 6 are evenly distributed around the circumference of the receiving groove 5. When the first piston 82 squeezes the air in the inner cavity of the packer body 1 and continuously fills the inner cavity of the rubber air bag 83 through the air holes 6, the rubber air bag 83 can be radially outward to fit against the inner wall of the oil well casing to form an annular auxiliary sealing layer, which together with the rubber sleeve 10 constitutes a double-layer sealing barrier structure.

[0029] As a preferred option, the Hall sensor 74 and the ring Hall sensor 855 form a dual-channel magnetic sensing monitoring system. The Hall sensor 74 collects the rotation signal of the rotating cylinder 71 to determine the sealing status of the rubber cylinder 10, and the ring Hall sensor 855 collects the displacement signal of the second permanent magnet 853 to determine the interlayer pressure difference leakage status. The two sensing signals are collected independently and transmitted to the ground synchronously through wired cables.

[0030] Its detailed connection method is a well-known technology in this field. The following mainly introduces the working principle and process, and the specific work is as follows.

[0031] Step 1: The surface drilling winch connects to the downhole tubing string. A central tube 13 runs through the tubing string. As the winch lowers the tubing string, it simultaneously moves the central tube 13 and the entire packer body 1 downwards along the well casing. Throughout the entire lowering process, the slip components 12, the rubber sleeve 10, and the rubber airbag 83 remain in a contracted state. The outer front end of the central tube 13 has a special axial sliding track. A limiting pin is installed inside the slip component 12, and the pin of the slip component 12 is embedded in the central tube 1. 3. Inside the outer wall sliding track, when the tubing string is lowered, the central tube 13 moves downward, and the inner wall of the track pushes against the internal pin of the slip component 12, which simultaneously drives the slip component 12 to slide smoothly downward with the packer body 1. The slip component 12 relies on its own built-in support spring to close and fit against the outer wall of the central tube 13. The slip teeth do not contact the inner wall of the well casing, avoiding scratching the well casing during lowering. After lowering to the target packer section depth in the well, the winch lowering action is stopped, and the packer lowering and positioning is completed. Step 2: After positioning is completed, the ground winch performs a reciprocating lifting operation. First, the tubing string is lifted upwards by 4 to 8 inches. The central tube 13 moves upwards synchronously with the tubing. The sliding rail on the outer wall of the central tube 13 pulls the internal pin of the slip component 12 to slide along the rail to switch positions. Then, the tubing string is slowly lowered to release the load. The rail pin falls into the locking groove. The axial load generated by the lowering of the tubing string is transmitted along the central tube 13 through the packer body 1 to the cone block 11. The cone block 11 moves forward axially. The conical inclined surface of the cone block 11 squeezes the slip component 12 to expand radially outwards. The hard slip teeth of the slip component 12 tightly bite the inner wall of the well casing. Relying on the reverse support force of the inner wall of the well casing, the radial position of the slip component 12 is locked. The slip component 12 can no longer expand outwards or slide axially, thus completing the downhole anchoring and fixing of the entire packer, providing a fixed support reference for the subsequent compression sealing of the rubber sleeve 10. Step 3: After the slip component 12 engages with the inner wall of the well casing and locks in place, the surface winch continues to apply axial thrust, pushing the central tube 13 forward axially. Since the slip component 12 is fixed to the inner wall of the well casing, the inner wall of the slip component 12 forms a rigid block against the cone block 11, preventing the cone block 11 from moving forward synchronously with the central tube 13. When the central tube 13 moves forward, the packer body 1 moves forward synchronously with the central tube 13, causing the packer body 1 and the fixed cone block 11 to move axially relative to each other. The connecting ring 9 and the rubber sleeve 10 are sandwiched between the front end of the packer body 1 and the rear end of the cone block 11. The forward axial extrusion force of the packer body 1 directly acts on the connecting ring 9 and is then transmitted to the rubber sleeve 10. Under the action of bidirectional extrusion load, the rubber sleeve 10 expands radially, and the outer wall of the rubber sleeve 10 tightly adheres to the inner wall of the well casing, forming the first main sealing layer to isolate the well fluid above and below the packer. Step 4: The position of the cone block 11 is locked and fixed by the slip component 12. The casing 81, which is fixed to the middle of the rear end of the cone block 11, remains axially stationary. The packer body 1 moves forward with the central tube 13, and the two generate axial relative displacement. The casing 81 slides backward relative to the packer body 1. The first piston 82, which is fixedly connected to the rear end of the casing 81, moves backward along the inner cavity of the packer body 1. During the backward sliding process of the first piston 82, it continuously squeezes the sealed air in the inner cavity of the packer body 1. The compressed air flows into the inner cavity of the rubber airbag 83 inside the receiving groove 5 through multiple sets of air holes 6 evenly distributed circumferentially along the inner wall of the receiving groove 5. The air pressure inside the rubber airbag 83 continues to rise, and the rubber material expands radially. The outer wall of the rubber airbag 83 is tightly attached to the inner wall of the oil well casing, forming an annular auxiliary sealing layer. Together with the expanded rubber sleeve 10 at the front end, it forms a double-layer sealing barrier structure, which improves the sealing reliability in deep water and high pressure conditions. Step 5: Two drive columns 75 are equidistantly fixed to the outer wall of the sleeve 81. The two drive columns 75 are slidably embedded in the two spiral grooves 72 with an included angle of 180° on the inner wall of the rotating cylinder 71. When the sleeve 81 moves axially backward relative to the packer body 1, the drive columns 75 slide backward along the grooves of the spiral grooves 72. The linear axial motion is converted into the circumferential rotational motion of the rotating cylinder 71. The two ends of the rotating cylinder 71 are supported by bearings at the front end of the packer body 1 and the rear side of the connecting ring 9, respectively, allowing for unobstructed circumferential rotation. The first permanent magnet 73 fixed at the bottom rear side of the rotating cylinder 71 follows the rotating cylinder 71. 1. When the drive column 75 slides to the end limit position of the spiral groove 72, the rotating cylinder 71 completes a 180° rotation. At this time, the first permanent magnet 73 rotates to the corresponding position symmetrical to the Hall sensor 74 on the top side of the front end of the packer body 1. The Hall sensor 74 captures the magnetic field change of the first permanent magnet 73 in real time, generates a stable electrical signal and transmits it to the ground control system through a wired cable. After receiving the signal, the ground determines that the double seal of the rubber cylinder 10 and the rubber airbag 83 is fully set in place, and then controls the winch to stop pushing the central tube 13 forward, and the setting construction process ends. Step Six: After the sealing is completed, under normal production conditions, the double-layer seal of the rubber sleeve 10 and the rubber airbag 83 is intact, and the formation fluid in the upper and lower wellbore cannot flow across. The pressure of the interlayer annulus between the rubber sleeve 10 and the rubber airbag 83 is stable without fluctuation. The second connecting hole 4 on the outer wall of the packer body 1 connects the interlayer annulus with the front side of the inner cavity of the differential pressure sensing chamber 2, and the first connecting hole 3 connects the rear side of the inner cavity of the differential pressure sensing chamber 2 with the rear wellbore of the packer. The fluid pressure on the front and rear sides inside the differential pressure sensing chamber 2 is completely equal. The front and rear ends of the second piston 851 inside the alarm component 85 bear the same fluid pressure, and the pressure cancels each other out. The spring 854 remains naturally extended without elastic compression deformation. The second permanent magnet 853 fixed at the rear end of the limiting cylinder 852 is far away from the annular Hall sensor 855 on the rear side of the inner cavity of the differential pressure sensing chamber 2. The annular Hall sensor 855 cannot sense the magnetic field of the second permanent magnet 853, and no leakage alarm signal is transmitted to the ground, indicating that the sealing condition is intact. Step 7: During long-term underwater high-pressure service, the rubber sleeve 10 is prone to damage and leakage due to continuous high-pressure extrusion in deep water, erosion by corrosive media in the well, abrasion by solid particles in the well, and fatigue aging caused by long-term reciprocating pressure differential. The high-pressure fluid in the well shaft escapes through the damaged gap of the rubber sleeve 10 to the annulus between the rubber sleeve 10 and the rubber airbag 83. The internal pressure of the annulus rises rapidly. At this time, the rubber airbag 83 remains completely sealed, which can prevent the high-pressure fluid from continuing to leak into the subsequent well shaft. The high-pressure fluid in the annulus can only flow into the front side of the inner cavity of the differential pressure sensing chamber 2 through the second connecting hole 4. The rear side of the inner cavity of the differential pressure sensing chamber 2 is connected to the subsequent low-pressure well shaft through the first connecting hole 3. A significant pressure difference is formed between the front and rear ends of the differential pressure sensing chamber 2. The pressure at the front end of the second piston 851 is greater than that at the rear end. The axial pressure difference continues to act on the front end face of the second piston 851. Step 8: As the pressure difference between the front and rear ends of the differential pressure sensing chamber 2 continues to increase, the high-pressure fluid pushes the second piston 851 to slide backward along the inner wall of the differential pressure sensing chamber 2. The two ends of the spring 854 sleeved at the rear end of the second piston 851 are respectively engaged with the rear side of the second piston 851 and the rear wall of the inner cavity of the differential pressure sensing chamber 2. During the backward movement of the second piston 851, the spring 854 is continuously squeezed, and the spring 854 undergoes compressive elastic deformation. The limiting cylinder 852 is fixedly connected to the rear side of the second piston 851. The limiting cylinder 852 moves backward axially in sync with the second piston 851. The second permanent magnet 853 mounted at the rear end of the limiting cylinder 852 moves synchronously to the sensing area corresponding to the ring Hall sensor 855. The ring Hall sensor 855 captures the magnetic field signal of the second permanent magnet 853 in real time and continuously transmits the sensing signal to the ground control terminal through the built-in wired cable. After receiving the signal, the ground system triggers an audible and visual alarm, providing real-time warnings of the seal damage of the downhole rubber sleeve 10 and the risk of interlayer leakage, facilitating timely well repair operations by the staff.

[0032] This device features a double-layer sealing structure to enhance the reliability of long-term sealing in deep water. It is equipped with dual independent magnetic sensors to achieve accurate identification of the set seal and online early warning of leaks. This overcomes the shortcomings of traditional packers, such as easy damage to single-layer seals, large errors in construction judgment, and delayed detection of leaks. It significantly improves the controllability of deep-sea oil and gas stratification and the safety of downhole operations.

[0033] 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 highly reliable underwater packer, characterized in that, include: The packer body (1) has a pressure differential sensing cavity (2) in the middle of its outer wall. The upper and lower rear ends of the packer body (1) are provided with first connecting holes (3) that communicate with the inner cavity of the pressure differential sensing cavity (2). The upper and lower front ends of the packer body (1) are provided with second connecting holes (4) that communicate with the inner cavity of the pressure differential sensing cavity (2). The packer body (1) has a storage groove (5) in the middle of its outer wall. The inner wall of the storage groove (5) has several air holes (6) that communicate with the inner cavity of the packer body (1) at equal intervals along the circumference. The second connecting hole (4) is located on the front side of the storage groove (5), and the first connecting hole (3) is located on the rear side of the storage groove (5). Indicating mechanism (7), the indicating mechanism (7) is disposed at the front end of the packer body (1); Monitoring mechanism (8), wherein the monitoring mechanism (8) is disposed in the inner cavity of the differential pressure sensing cavity (2); A connecting ring (9) is disposed at the front end of the indicating mechanism (7); A rubber tube (10) is disposed at the front end of the connecting ring (9); A cone-shaped block (11) is disposed at the front end of the rubber tube (10); The central tube (13) is located in the inner cavity of the packer body (1) on the rear side of its outer wall. The front end of the central tube (13) can slide through the inner cavity of the indicator mechanism (7), the connecting ring (9), the rubber tube (10) and the cone block (11). The slip component (12) is slidably and appropriately fitted to the front end of the outer wall of the central tube (13). The slip component (12) and the cone block (11) are in contact and matched.

2. The underwater packer with high sealing reliability according to claim 1, characterized in that, The indicating mechanism (7) includes: The rear end of the rotating cylinder (71) is rotatably disposed at the front end of the packer body (1) via a bearing. The front end of the rotating cylinder (71) is rotatably disposed at the rear side of the connecting ring (9) via a bearing. Two spiral grooves (72) are equidistantly opened on the inner wall of the rotating cylinder (71) along the circumferential direction. The first permanent magnet (73) is disposed at the rear bottom end of the rotating cylinder (71); Hall sensor (74) is disposed on the top front end of the packer body (1), and the Hall sensor (74) and the first permanent magnet (73) are symmetrical about the axis of the central tube (13).

3. The underwater packer with high sealing reliability according to claim 2, characterized in that, The included angle between the front and rear ends of the spiral groove (72) is 180 degrees.

4. The underwater packer with high sealing reliability according to claim 3, characterized in that, The monitoring agency (8) includes: The sleeve (81) is located at the middle of the rear end of the cone block (11). The central tube (13) is slidably adapted to be inserted into the inner cavity of the sleeve (81). The outer wall of the sleeve (81) is slidably adapted to be inserted into the inner cavity of the connecting ring (9). The rear end of the sleeve (81) extends slidably into the front side of the inner cavity of the packer body (1). The first piston (82) is disposed at the rear end of the sleeve (81). The first piston (82) is slidably and appropriately inserted into the inner cavity of the packer body (1). The first piston (82) is slidably and appropriately inserted into the outer wall of the central tube (13). A rubber airbag (83) is disposed in the inner cavity of the receiving groove (5), and the inner cavity of the rubber airbag (83) is connected to the inner cavity of the air hole (6). Sleeve (84), the sleeve (84) is fitted onto the outer wall of the differential pressure sensing cavity (2); An alarm component (85) is disposed in the inner cavity of the differential pressure sensing cavity (2).

5. A high-sealing-reliability underwater packer according to claim 4, characterized in that, The alarm component (85) includes: The second piston (851) is slidably and appropriately connected to the inner wall of the differential pressure sensing chamber (2), and the second piston (851) is slidably and appropriately inserted into the inner cavity of the sleeve (84). A limiting cylinder (852) is disposed on the rear side of the second piston (851), and the limiting cylinder (852) is slidably and appropriately fitted to the inner wall of the differential pressure sensing chamber (2); The second permanent magnet (853) is disposed at the rear end of the limiting cylinder (852); Spring (854), the spring (854) is sleeved on the inner wall of the differential pressure sensing chamber (2), one end of the spring (854) is clamped to the rear side of the second piston (851), and the other end of the spring (854) is clamped to the rear side of the inner cavity of the differential pressure sensing chamber (2); A ring Hall sensor (855) is disposed on the rear side of the inner cavity of the differential pressure sensing cavity (2), and the position of the ring Hall sensor (855) corresponds to the position of the second permanent magnet (853).

6. A high-sealing-reliability underwater packer according to claim 5, characterized in that, The outer wall of the sleeve (81) is provided with two drive posts (75) at equal intervals along the circumference. The two drive posts (75) are slidably adapted to be inserted into the front side of the inner cavity of the two spiral grooves (72).

7. A high-sealing-reliability underwater packer according to claim 6, characterized in that, The air holes (6) are evenly arranged in multiple sets along the circumference of the receiving groove (5). When the first piston (82) squeezes the air in the inner cavity of the packer body (1) and continuously fills the inner cavity of the rubber air bag (83) through the air holes (6), the rubber air bag (83) can be radially outward to fit against the inner wall of the oil well casing to form an annular auxiliary sealing layer, which together with the rubber sleeve (10) constitutes a double-layer sealing barrier structure.

8. A high-sealing-reliability underwater packer according to claim 7, characterized in that, The Hall sensor (74) and the ring Hall sensor (855) form a dual-channel magnetic sensing monitoring system. The Hall sensor (74) collects the rotation signal of the rotating cylinder (71) to determine the sealing status of the rubber cylinder (10). The ring Hall sensor (855) collects the displacement signal of the second permanent magnet (853) to determine the interlayer pressure difference leakage status. The two sensing signals are collected independently and transmitted to the ground synchronously through wired cables.

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