Hydraulic control type oil sleeve pressure connection and oil pipe blowout prevention tool and control system thereof

Abstract

The present application relates to the technical field of oilfield production engineering, and particularly relates to a hydraulic control type oil casing pressure connection and tubing blowout prevention tool and a control system thereof. The hydraulic control type oil casing pressure connection and tubing blowout prevention tool comprises an upper joint, the upper joint is sleeved with an upper sleeve; the upper sleeve is sleeved with a lower sleeve; the inner side of the lower sleeve is inserted with a lower joint; the upper sleeve is inserted with a spring claw; the inner side of the spring claw is inserted with a sliding sleeve and a center pipe, the sliding sleeve and the center pipe are arranged along an axial direction; a conveying channel is formed between the upper joint, the sliding sleeve, the center pipe and the lower joint; a first cavity is formed between the center pipe, the spring claw and the upper sleeve; a second cavity is formed between the upper sleeve, the center pipe, the lower sleeve and the lower joint; a sealing sleeve is inserted in the second cavity, the sealing sleeve is elastically hinged with a valve plate; a third cavity is formed between the spring claw and the upper sleeve. The hydraulic control principle is used, the position of the spring claw, the sliding sleeve and the center pipe is switched, and the oil casing pressure connection and the tubing blowout prevention are realized.

Description

Technical Field

[0001] This invention relates to the field of oilfield production engineering technology, and in particular to a hydraulically controlled oil casing pressure connection and tubing blowout preventer tool and its control system. Background Technology

[0002] As oilfield development continues to deepen both domestically and internationally, the industry faces a significant challenge of imbalanced reservoir development structure: on the one hand, the reserves of easily exploitable high-quality reservoirs with high permeability and large effective thickness are increasingly depleted, and their development potential is nearing its limit; on the other hand, Class II and III thin and poor reservoirs still contain abundant remaining geological reserves, becoming the core potential area for current and future oilfield production improvement.

[0003] However, Class II and III thin and poor reservoirs generally have low or extremely low permeability geological characteristics, and effective development can only be achieved through fracturing. This is especially true for many old wells with a long development history, which require repeated fracturing operations to restore or increase production capacity. At the same time, Class II and III thin and poor reservoirs also have the prominent feature of large vertical thickness differences, which places higher demands on the adaptability and reliability of fracturing technology and supporting tools.

[0004] The currently used drag-type fracturing process requires multiple re-seat and unseat cycles for the packer. Post-fracturing pressure balancing is slow, packer sleeve recovery is slow, and the tubing string is easily damaged during lifting. Therefore, a pressure connection device is needed to balance the pressure above and below the packer sleeve. Furthermore, a blowout preventer is required during tubing string lifting, and the tubing passage must be closed before lifting the string. Well and layer selection is difficult, with poor adaptability, low efficiency, and high costs, posing certain safety hazards to oil extraction.

[0005] In related technologies, such as the pressure-holding, double-seal drag fracturing process string disclosed in Chinese patent CN205638336U, the tubing string is simultaneously set and then released in stages. The release stroke is controlled by the lowering stroke of the tubing string. When the tubing string is dragged upwards to the next stage, the release stroke automatically returns to the initial state, achieving the purpose of repeated setting and release. This existing drag fracturing process results in slow oil-casing pressure balance after fracturing and slow packer sleeve recovery. Another example is a blowout preventer valve disclosed in Chinese patent CN204571928U, which is designed for multi-stage, high-volume sand fracturing operations. It requires raising and lowering the tubing string during each stage of fracturing, which can easily damage the tubing string and affect the blowout preventer effect.

[0006] Therefore, it is necessary to develop a new type of hydraulically controlled oil casing pressure connection and tubing blowout prevention tool to adapt to changes in reservoir thickness, realize the efficient development of Class II and III thin and poor reservoirs, and improve the safety and efficiency of oil extraction. Summary of the Invention

[0007] Based on this, it is necessary to address the problems existing in the current oilfield production process, such as the need for packers to be repeatedly set and unsealed, slow oil-casing pressure balance after fracturing, slow packer sleeve recovery, easy damage to the lifting tubing string, and the need for additional pressure connection devices to balance the pressure above and below the sleeve. Therefore, it is necessary to provide a hydraulically controlled oil-casing pressure connection and tubing blowout prevention tool and its control system.

[0008] The above objectives are achieved through the following technical solutions: A hydraulically controlled oil casing pressure connection and tubing blowout preventer is disclosed. The hydraulically controlled oil casing pressure connection and tubing blowout preventer is inserted into the tubing, forming an oil channel between the tool and the tubing. This oil channel receives fracturing fluid from the outside. The hydraulically controlled oil casing pressure connection and tubing blowout preventer includes an upper connector; an upper outer sleeve is fitted onto the upper connector; a lower outer sleeve is fitted onto the upper outer sleeve; a lower connector is inserted inside the lower outer sleeve; a spring claw is inserted inside the upper outer sleeve; a sliding sleeve and a central tube are inserted inside the spring claw, arranged axially; a delivery channel is formed between the upper connector, sliding sleeve, central tube, and lower connector; a first chamber is formed between the central tube, spring claw, and upper outer sleeve, and the first chamber communicates with the delivery channel; multiple elastic hooks are provided on the spring claw, arranged circumferentially and all located within the first chamber, with the hook ends facing outwards and capable of engaging with grooves on the upper outer sleeve; an adjustment mechanism is fitted onto the central tube. The adjusting ring is located in the first chamber and can slide axially, forming a stop with all the elastic hooks. A second chamber is formed between the upper outer sleeve, the central tube, the lower outer sleeve, and the lower connector. A sealing sleeve is inserted in the second chamber, and a valve plate is elastically hinged to the sealing sleeve. Under the action of elasticity, the valve plate can both form a stop with the central tube and cut off the conveying channel laterally. A third chamber is formed between the spring claw and the upper outer sleeve. The third chamber is connected to the oil channel, so that the spring claw can synchronously drive the sliding sleeve and the central tube to slide axially. Before sliding, it has a first position, at which time the elastic hook and the upper outer sleeve are engaged. After sliding, it has a second position and a third position in sequence. When it is in the second position, the elastic hook and the upper outer sleeve are engaged, and the first chamber is connected to the oil channel and the conveying channel. When it is in the third position, the elastic hook and the upper outer sleeve are engaged, the second chamber is connected to the conveying channel, and the valve plate cuts off the conveying channel laterally.

[0009] Furthermore, a valve seat is inserted between the upper outer sleeve and the central tube, the valve seat is fixedly connected to the upper outer sleeve, and the valve seat is slidably connected to the central tube in a sealed manner; the second chamber is formed by the upper outer sleeve, the valve seat, the central tube, and the lower connector of the lower outer sleeve.

[0010] Furthermore, the valve plate is connected to the sealing sleeve via a first elastic element; the first elastic element is a torsion spring, and under the action of the torsion spring, the valve plate tends to rotate towards the side closer to the conveying channel.

[0011] Furthermore, a fourth chamber is formed between the upper connector, the upper outer sleeve, the sliding sleeve, and the spring claw. The fourth chamber is unidirectionally connected to the conveying channel, and the connection direction is from the conveying channel to the fourth chamber. A filter structure is provided at the connection point. A nozzle is provided on the hook end of the elastic hook, and the nozzle faces the upper outer sleeve. A flow channel is provided inside the spring claw and the elastic hook, and the flow channel connects the nozzle and the fourth chamber.

[0012] Furthermore, the hook end of the elastic hook has a portion of its structure and a slot that are spaced apart and connected to the nozzle.

[0013] Furthermore, the inner wall of the outer jacket can completely seal the nozzle.

[0014] Furthermore, the spring claw has a fifth chamber inside, which is connected to the flow channel; a piston rod is inserted into the fifth chamber, and the piston rod and the fifth chamber form a piston fit and can slide elastically along the axial direction; the adjusting ring has a fixed sub-ring and a sliding sub-ring arranged coaxially, the sliding sub-ring is located on the outside and can slide relative to the fixed sub-ring along the axial direction, and is fixedly connected to the piston rod.

[0015] Furthermore, the piston rod is connected to a spring claw via a second elastic element; the second elastic element is a coil spring.

[0016] Furthermore, the fourth chamber and the conveying channel have multiple connection points, each of which is unidirectional and each connection point is equipped with a filter structure.

[0017] This invention also provides a control system for a hydraulically controlled oil casing pressure connection and tubing blowout preventer, applied to a hydraulically controlled oil casing pressure connection and tubing blowout preventer. The control system for the hydraulically controlled oil casing pressure connection and tubing blowout preventer includes: The controller is configured to operate the hydraulic sleeve pressure connection and the tubing blowout preventer according to a preset program, which includes the following steps: S1. Lower the hydraulically controlled oil casing pressure connection and tubing blowout preventer and tubing to the preset position inside the oil well; S2. Fracturing fluid is delivered into the oil channel to develop the oil well through fracturing technology; S3. Increase the pressure of the fracturing fluid entering the third chamber. Under hydraulic action, the spring claw, sliding sleeve, and central tube move as a whole closer to the upper joint, and first move from the first position to the second position. At this time, the elastic hook and the upper outer sleeve engage, and the first chamber connects the oil passage and the delivery passage, realizing the pressure connection between the oil and casing. Then, it moves from the second position to the third position. At this time, the elastic hook and the upper outer sleeve engage, and the second chamber connects to the delivery passage. The valve plate laterally cuts off the delivery passage, realizing the oil pipe blowout prevention. S4, drives the hydraulically controlled oil jacket pressure connection and the oil pipe blowout preventer and oil pipe to move upward; S5, drives the spring claw, sliding sleeve and central tube to reset as a whole; S6. Repeat S1-S5.

[0018] The beneficial effects of this invention are: This invention relates to a hydraulically controlled oil casing pressure connection and tubing blowout prevention tool and its control system. It comprises a spring claw, a valve plate, and a delivery channel, with a first chamber and a second chamber that cooperate with the delivery channel. When the spring claw is in the first position, the oil well is developed using a drag-type fracturing process. When the spring claw is in the second position, the first chamber connects the oil channel and the delivery channel, achieving oil casing pressure connection. When the spring claw is in the third position, the second chamber connects to the delivery channel, and the valve plate laterally cuts off the delivery channel, achieving tubing blowout prevention, preventing uncontrolled oil leakage, and ensuring operational safety and stable well operation.

[0019] Furthermore, by setting up a fourth chamber that is unidirectionally connected to the conveying channel, a flow channel connected to the fourth chamber, and a nozzle connected to the flow channel, and by setting a filter structure at the connection between the conveying channel and the fourth chamber, the liquid in the conveying channel is filtered by the filter structure and then enters the fourth chamber. Then, as the spring claw moves, the liquid in the fourth chamber passes through the flow channel and is sprayed out from the nozzle. This not only cleans the impurities accumulated at the slot, avoiding affecting the locking effect between the elastic hook and the slot, but also acts as a lubricating medium, which helps to reduce the friction intensity between the elastic hook and the upper outer sleeve.

[0020] Furthermore, by setting a fifth chamber, a piston rod that forms a piston-like fit with the fifth chamber, and an adjusting ring with a fixed sub-ring and a sliding sub-ring arranged coaxially, and utilizing the characteristic that the sliding sub-ring can slide axially relative to the fixed sub-ring and is fixedly connected to the piston rod, the liquid in the delivery channel is filtered by the filter structure and enters the fourth chamber. Then, as the spring claw moves, the liquid in the fourth chamber enters the fifth chamber through the flow channel. Under hydraulic action, the piston rod drives the sliding sub-ring to move, reducing the elastic restoring force of the elastic hook, reducing the normal pressure between the elastic hook and the upper outer sleeve, and reducing the friction between the elastic hook and the upper outer sleeve, thereby further reducing the wear of the elastic hook and the upper outer sleeve. At the same time, when the spring claw is in the first position, the adjusting ring can be located closer to the hook end of the elastic hook, making it more difficult for the elastic hook to disengage from the slot, which is beneficial to improving the stability of the hydraulically controlled casing pressure connection and tubing blowout preventer when developing oil wells using the drag-type fracturing process. Attached Figure Description

[0021] Figure 1 This is a half-sectional view of the hydraulically controlled oil jacket pressure connection and tubing blowout preventer provided in the first embodiment of the present invention. Figure 2A semi-sectional view of the hydraulically controlled oil jacket pressure connection and tubing blowout preventer provided in the second embodiment of the present invention. Figure 1 ; Figure 3 A semi-sectional view of the hydraulically controlled oil jacket pressure connection and tubing blowout preventer provided in the second embodiment of the present invention. Figure 2 ; Figure 4 for Figure 3 A magnified schematic diagram of the structure at point V in the middle; Figure 5 for Figure 4 A magnified schematic diagram of the structure at point W in the middle; Figure 6 A semi-sectional view of the hydraulically controlled oil jacket pressure connection and tubing blowout preventer provided in the second embodiment of the present invention. Figure 3 ; Figure 7 for Figure 6 A magnified schematic diagram of the structure at point X in the middle; Figure 8 A semi-sectional view of the hydraulically controlled oil jacket pressure connection and tubing blowout preventer provided in the second embodiment of the present invention. Figure 4 ; Figure 9 for Figure 8 A magnified schematic diagram of the structure at point Y in the middle; Figure 10 A semi-sectional view of the hydraulically controlled oil jacket pressure connection and tubing blowout preventer provided in the second embodiment of the present invention. Figure 5 ; Figure 11 for Figure 10 A magnified schematic diagram of the structure at point Z in the middle; Figure 12 This is a three-dimensional structural diagram of the spring claw, adjusting ring, piston rod, and helical spring assembly of the hydraulically controlled oil jacket pressure connection and oil pipe blowout preventer provided in the second embodiment of the present invention.

[0022] in: 1. Upper connector; 2. Anti-rotation pin I; 3. Upper outer sleeve; 301. Liquid inlet; 302. Balance port; 303. Slot; 304. Second annular groove; 4. Sliding sleeve; 5. Spring claw; 501. Elastic hook; 5011. Nozzle; 502. Flow channel; 503. Fifth chamber; 504. First annular groove; 6. Central tube; 601. First connecting port; 7. Adjusting ring; 701. Fixed sub-ring; 702. Sliding sub-ring; 8. Valve seat; 9. Lower outer sleeve; 10. Sealing sleeve; 11. Valve shaft; 12. Valve plate; 13. Lower connector; 14. Anti-rotation pin II; 15. Anti-rotation pin III; 16. Conveying channel; 17. First chamber; 18. Second chamber; 19. Third chamber; 20. Fourth chamber; 21. Filter screen; 22. One-way valve; 23. Piston rod; 24. Helical spring. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below through embodiments and in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0024] The component designations used in this document, such as "first" and "second," are merely for distinguishing the described objects and do not have any sequential or technical meaning. The terms "connection" and "linkage," unless otherwise specified, include both direct and indirect connections (linkages). In the description of this invention, it should be understood that the terms "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting the invention.

[0025] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0026] Currently, the widely used drag-type fracturing process in the industry requires packers to undergo repeated setting and unsetting operations with each fracturing stage when developing thin and poor reservoirs. This not only makes the operation process cumbersome but also significantly increases the risk of tool wear. Furthermore, after fracturing, the pressure equalization rate in the annulus and tubing is slow, directly leading to low packer cartridge recovery efficiency and prolonging the operation cycle. Incomplete cartridge recovery increases resistance during tubing string lifting, easily causing tubing wear, deformation, or even damage. To solve this problem, an additional pressure connection device is needed to balance the pressure above and below the cartridge, further increasing the process complexity. The complexity and equipment cost are significant factors. In the tubing string lifting operation, to prevent fluid overflow in the well, it is necessary to ensure that the tubing channel is effectively closed to achieve the blowout prevention function. However, existing tools cannot balance blowout prevention reliability and ease of operation. At the same time, due to the limitations of tool performance and process characteristics, the existing drag-and-drop fracturing process has obvious limitations in well type selection and reservoir section screening. Well and layer selection is difficult, and the adaptability to different geological conditions is poor. Ultimately, this leads to low overall operation efficiency and high comprehensive costs. When the above problems are combined, they also create safety hazards such as tubing string failure and well control risks for oil extraction operations, which seriously restricts the efficient development of thin and poor reservoirs.

[0027] Based on this, the first embodiment of the present invention provides a hydraulically controlled oil casing pressure connection and tubing blowout preventer, which is inserted into the tubing during installation and forms an oil channel between itself and the tubing. The oil channel is used to receive fracturing fluid from the outside. The hydraulically controlled oil casing pressure connection and tubing blowout preventer is particularly suitable for drag fracturing processes.

[0028] Specifically, refer to Figure 1The hydraulically controlled oil jacket pressure connection and oil pipe blowout preventer is configured as follows: An upper connector 1, which is a sleeve-shaped structure, is threaded onto the right end of the upper connector 1 with an upper outer sleeve 3. The upper outer sleeve 3 is fixedly connected to the upper connector 1 via an anti-rotation pin I2. The anti-rotation pin I2 can be configured to penetrate the upper outer sleeve 3 radially inward and be threaded or frictionally inserted into the side wall of the upper connector 1. A sealing ring is inserted between the upper connector 1 and the upper outer sleeve 3 to ensure sealing. A lower outer sleeve 9 is threaded onto the right end of the upper outer sleeve 3. The lower outer sleeve 9 is fixedly connected to the upper outer sleeve 3 via an anti-rotation pin III15. The anti-rotation pin III15 can be configured to penetrate the lower outer sleeve 9 radially inward and be threaded or frictionally inserted into the side wall of the upper outer sleeve 3. A sealing ring is inserted between the upper outer sleeve 3 and the lower outer sleeve 9 to ensure a tight seal. A lower connector 13 is threaded into the right end of the lower outer sleeve 9. The lower connector 13 is a sleeve-shaped structure and is fixedly connected to the lower outer sleeve 9 by an anti-rotation pin II 14. The anti-rotation pin II 14 can be configured to penetrate the lower outer sleeve 9 radially inward and be threaded or frictionally inserted into the side wall of the lower connector 13. A sealing ring is inserted between the lower connector 13 and the lower outer sleeve 9 to ensure a tight seal. A spring claw 5 is inserted into the inner side of the upper outer sleeve 3. The spring claw 5 is a sleeve-shaped structure and frictionally abuts against the upper outer sleeve 3. A sliding sleeve 4 and a central tube 6 are threaded into the inner side of the spring claw 5. The sliding sleeve 4 and the central tube 6 are arranged axially, and the sliding sleeve 4 is located on the left side of the central tube 6.

[0029] A conveying channel 16 is formed by the inner sides of the upper connector 1, the sliding sleeve 4, the central tube 6, and the lower connector 13. The conveying channel 16 is used to convey a mixture of crude oil, gravel, and soil. A first chamber 17 is formed by the outer side of the central tube 6, the inner side of the upper sleeve 3, and the right end face of the spring claw 5. The first chamber 17 has an annular structure, and a first connecting port 601 is provided on the side wall of the central tube 6. The first connecting port 601 connects the first chamber 17 and the conveying channel 16. Multiple elastic hooks 501 are provided on the right end face of the spring claw 5. The multiple elastic hooks 501 are evenly arranged circumferentially and are all located in the first chamber 17. The elastic hooks 501 extend in a direction parallel to the axis of the spring claw 5, and the hook ends are away from the spring claw 5 and are set outward. The hook ends of the elastic hooks 501 can form a snap-fit ​​with the slots 303 on the upper outer sleeve 3 to facilitate locking the position of the spring claw 5. The hook ends of the elastic hooks 501 can swing elastically around their other ends. Three sets of slots 303 are provided on the inner peripheral wall of the upper outer sleeve 3. The three sets of slots 303 are arranged axially at intervals and are all located in the first chamber 17. Each set includes a number of slots 303 equal to the number of elastic hooks 501. Multiple slots 303 in the same set are evenly arranged circumferentially and are set corresponding to the elastic hooks 501 to facilitate snap-fit ​​with the hook ends of the elastic hooks 501.

[0030] An adjusting ring 7 is threaded onto the central tube 6. The threaded engagement allows the adjusting ring 7 to slide axially, and its position after sliding can be locked. The adjusting ring 7 is located within the first chamber 17 and simultaneously forms a stop engagement with the inner walls of all the elastic hooks 501, allowing the swing fulcrum of the hook end of the elastic hook 501 to be changed. At this time, the swing fulcrum of the hook end of the elastic hook 501 is the right end of the adjusting ring 7. When the adjusting ring 7 moves to the left, the swing fulcrum of the hook end of the elastic hook 501 moves to the left, reducing the resistance encountered by the hook end of the elastic hook 501 during swing. When the locking force of the elastic hook 501 when it engages with the slot 303 is reduced, and the elastic restoring force generated after swinging is smaller, the normal pressure and friction between the hook end of the elastic hook 501 and the inner wall of the upper outer sleeve 3 are reduced. Similarly, when the adjusting ring 7 moves to the right, the swing fulcrum of the hook end of the elastic hook 501 moves to the right, which increases the resistance encountered by the hook end of the elastic hook 501 when swinging, increases the locking force when it engages with the slot 303, and increases the elastic restoring force generated after swinging, which increases the normal pressure and friction between the hook end of the elastic hook 501 and the inner wall of the upper outer sleeve 3.

[0031] The right end face of the upper outer sleeve 3, the inner side of the lower outer sleeve 9, the outer side of the central tube 6, and the left end face of the lower connector 13 together form a second chamber 18, which is an annular structure. A sealing sleeve 10 is inserted into the second chamber 18, and the sealing sleeve 10 is sealed and fixedly connected to the lower outer sleeve 9 by a sealing ring. A valve shaft 11 is fixedly installed at the right end of the sealing sleeve 10, and the valve shaft 11 and the sealing sleeve 10 are arranged perpendicularly. A valve plate 12 is sleeved on the valve shaft 11, and the valve plate 12 can rotate around the valve shaft 11 to form a hinged fit. A first elastic element is connected between the valve shaft 11 and the valve plate 12. Under the action of the first elastic element, the valve plate 12 has a tendency to rotate towards the side closer to the conveying channel 16, so as to form a stop fit with the central tube 6. The valve plate 12 has a disc-shaped structure, so when the second chamber 18 and the conveying channel 16 are connected, under the action of the first elastic element, the valve plate 12 can rotate to insert into the conveying channel 16 and cut off the conveying channel 16 laterally. The first elastic element can be set as a torsion spring.

[0032] A first annular groove 504 is provided on the outer wall of the spring claw 5, which forms two relatively convex annular portions on the outer wall of the spring claw 5. A second annular groove 304 is provided on the inner wall of the upper outer sleeve 3, which is located near the left end face of the upper outer sleeve 3. The outer wall of the relatively convex annular portion on the left side of the spring claw 5 and the groove wall of the second annular groove 304 form a sealing contact through a sealing ring. The outer wall of the relatively convex annular portion on the right side of the spring claw 5 and the inner wall of the upper outer sleeve 3 form a sealing contact through a sealing ring. The right end face of the relatively convex annular portion on the left side of the spring claw 5, part of the groove wall of the second annular groove 304, the groove wall of the first annular groove 504, and the left end face of the relatively convex annular portion on the right side of the spring claw 5 together form a third chamber 19, which is an annular structure. An inlet 301 and a balance port 302 are provided on the side wall of the upper outer sleeve 3. 02 are arranged axially at intervals, and the inlet 301 is located to the left of the balance port 302. Initially, both the inlet 301 and the balance port 302 are connected to the third chamber 19 and the oil passage. When the third chamber 19 is filled with fracturing fluid, the pressure of the fracturing fluid is set to P. The area of ​​the right end face of the relatively convex annular part on the left side of the spring claw 5 is S1. The fracturing fluid generates a leftward thrust F1=P*S1 on the spring claw 5 through the right end face of the relatively convex annular part on the left side of the spring claw 5. The area of ​​the left end face of the relatively convex annular part on the right side of the spring claw 5 is S2. The fracturing fluid generates a rightward thrust F2=P*S2 on the spring claw 5 through the left end face of the relatively convex annular part on the right side of the spring claw 5. Since S1 is greater than S2, F1 is greater than F2, so the hydraulic resultant force ΔF on the spring claw 5 is F1-F2, and the direction is to the left. Therefore, the spring claw 5 will only move to the left, that is, move towards the upper connector 1.

[0033] Before use, the position of the adjusting ring 7 on the central pipe 6 is changed according to the hardness of the soil layer to be fracturing in the oil well. The harder the soil layer to be fracturing in the oil well, the greater the degree to which the adjusting ring 7 is moved to the right. The reason for this design is that the harder the soil layer to be fracturing in the oil well, the greater the pressure P of the fracturing fluid entering the oil channel needs to be to ensure the fracturing effect. As the fracturing fluid pressure P increases, the hydraulic force ΔF=F1-F2 acting on the spring claw 5 to the left also increases. To ensure that the spring claw 5 does not move during the soil fracturing process and thus ensures the normal progress of the fracturing process, it is necessary to adjust the movement resistance of the spring claw 5 to be greater. When the adjusting ring 7 moves to the right, the swing fulcrum of the hook end of the elastic hook 501 moves to the right, which increases the normal pressure and friction between the hook end of the elastic hook 501 and the groove 303, making the engagement between the hook end of the elastic hook 501 and the groove 303 more stable, thereby preventing the spring claw 5 from moving during the soil fracturing process.

[0034] Initially, the hook end of the elastic hook 501 engages with the first slot 303 from right to left, at which point the spring claw 5, the sliding sleeve 4, and the central tube 6 are in the first position.

[0035] During operation, the hydraulically controlled casing pressure connection and tubing blowout preventer and tubing are first lowered to the preset position inside the well. Then, fracturing fluid is delivered into the oil channel, and the soil layer to be fractured in the well is fracturing using the fracturing process. At this time, the fracturing fluid simultaneously enters the third chamber 19 through the inlet 301 and the balance port 302, and tends to move the spring claw 5 to the left. However, due to the engagement between the elastic hook 501 and the first slot 303 from right to left, the spring claw 5 will not move. After fracturing is completed, the pressure of the fracturing fluid delivered in the oil channel is increased, and the pressure of the fracturing fluid entering the third chamber 19 is increased simultaneously. At this time, the hydraulic force on the spring claw 5 to the left increases, and under the action of the pressure difference, the spring claw 5... The sliding sleeve 4 and the central tube 6 move to the left as a whole, and first move from the first position to the second position. At this time, the hook end of the elastic hook 501 engages with the second slot 303 from the right to the left, and the balance port 302 is connected to the first chamber 17, so that the fracturing fluid in the oil channel can enter the delivery channel 16 in sequence through the balance port 302, the first chamber 17, and the first connecting port 601, thereby realizing the pressure connection between the oil sleeve and the casing. Then, it moves from the second position to the third position. At this time, the hook end of the elastic hook 501 engages with the third slot 303 from the right to the left, and the second chamber 18 is connected to the delivery channel 16. Under the action of the torsion spring, the valve plate 12 rotates inward around the valve shaft 11 to cut off the delivery channel 16 in the transverse direction, thereby realizing the oil pipe blowout prevention.

[0036] Alternatively, the slot 303 can also be configured as a ring structure, thereby enabling it to simultaneously engage with the hook ends of all the elastic hooks 501.

[0037] Optionally, to improve the liquid exchange efficiency between the delivery channel 16 and the third chamber 19, the number of inlet ports 301 and balance ports 302 can be set to be multiple, with multiple inlet ports 301 arranged at intervals along the circumference and multiple balance ports 302 arranged at intervals along the circumference.

[0038] Optionally, to achieve a sealed fit between the upper outer sleeve 3 and the central tube 6, the upper outer sleeve 3 and the central tube 6 can be connected by a sealing ring.

[0039] Optionally, in order to achieve both a sealed fit between the upper outer sleeve 3 and the central tube 6 and to facilitate processing and assembly, a valve seat 8 is threadedly inserted into the inner side of the right end of the upper outer sleeve 3. The valve seat 8 is simultaneously connected to the central tube 6 in a sealed sliding manner through a sealing ring. At this time, the second chamber 18 is formed by the right end face of the upper outer sleeve 3, the right end face of the valve seat 8, the outer side of the central tube 6, the inner side of the lower outer sleeve 9, and the left end face of the lower connector 13.

[0040] Reference Figures 2 to 12 The second embodiment of the present invention provides a hydraulically controlled oil jacket pressure connection and oil pipe blowout preventer, which is basically the same in structure as the first embodiment, except that the second annular groove 304 extends to the left end face of the upper outer sleeve 3, and a threaded groove is provided on the left side wall of the second annular groove 304 to facilitate threaded engagement with the upper connector 1; the right end face of the upper connector 1, the outer side of the sliding sleeve 4, the groove wall of the second annular groove 304 and the left end face of the spring claw 5 together form a fourth chamber 20, which is an annular structure; a second connecting port is provided on the side wall of the sliding sleeve 4, which connects the fourth chamber 20 and the oil pipe. The conveying channel 16 is equipped with a one-way valve 22 inserted in the second connecting port. The opening direction of the one-way valve 22 is from the conveying channel 16 to the fourth chamber 20. A filter structure is provided inside the second connecting port and inside the one-way valve 22. The filter structure is used to filter solid particles such as sand and soil contained in the liquid in the conveying channel 16. A nozzle 5011 is provided on the outer wall of the hook end of each elastic hook 501, and the nozzle 5011 faces the upper outer sleeve 3. A flow channel 502 is provided inside the spring claw 5 and inside each elastic hook 501. The flow channel 502 connects the nozzle 5011 and the fourth chamber 20.

[0041] During use, before the spring claw 5 moves, the liquid in the delivery channel 16 is filtered by the filter structure under the action of pressure difference, and then enters the fourth chamber 20 through the one-way valve 22 and is stored in the fourth chamber 20.

[0042] When the spring claw 5 moves, the volume of the fourth chamber 20 decreases and the pressure increases. Under the action of pressure difference, the liquid in the fourth chamber 20 passes through the flow channel 502 and is sprayed out from the nozzle 5011. When the hook end of the elastic hook 501 is at the slot 303, the liquid sprayed from the nozzle 5011 can wash away the impurities accumulated at the slot 303 and then return to the conveying channel 16 through the first connecting port 601, so as to avoid affecting the locking effect between the elastic hook 501 and the slot 303. When the hook end of the elastic hook 501 slides on the inner wall of the upper outer sleeve 3, the liquid sprayed from the nozzle 5011 can act as a lubricating medium, which helps to reduce the friction intensity between the elastic hook 501 and the upper outer sleeve 3, thereby reducing the wear of the elastic hook 501 and the upper outer sleeve 3.

[0043] Alternatively, the filter structure can be configured as a filter screen 21, a filter plate, etc.

[0044] Optionally, to improve the liquid exchange efficiency between the fourth chamber 20 and the delivery channel 16, multiple second connection ports are provided at the connection points between the fourth chamber 20 and the delivery channel 16, and these ports can be arranged at intervals along the circumference. Each second connection port is equipped with a one-way valve 22 and a filter structure.

[0045] Optionally, to reduce the impact of the liquid ejected from the nozzle 5011 on the engagement effect between the hook end of the elastic hook 501 and the slot 303, such as... Figure 9 As shown, the left side portion of the hook end of the elastic hook 501 is spaced apart from the slot 303 and connected to the nozzle 5011, so that the liquid sprayed from the nozzle 5011 can flow directly into the gap. While rinsing the impurities accumulated in the slot 303, it reduces the inward impact on the hook end of the elastic hook 501, and avoids causing the hook end of the elastic hook 501 to swing inward. This reduces the impact of the normal pressure and friction between the hook end of the elastic hook 501 and the slot 303, and thus reduces the impact on the locking effect between the hook end of the elastic hook 501 and the slot 303.

[0046] Optionally, to further reduce the wear of the hook end of the elastic hook 501 and the upper outer sleeve 3, the inner wall of the upper outer sleeve 3 is configured to completely block the nozzle 5011, so that the liquid sprayed from the nozzle 5011 can use a large hydraulic pressure to drive the hook end of the elastic hook 501 away from the inner wall of the upper outer sleeve 3. At this time, the normal pressure and friction between the hook end of the elastic hook 501 and the inner wall of the upper outer sleeve 3 are reduced, thereby reducing the wear of the hook end of the elastic hook 501 and the upper outer sleeve 3.

[0047] Optionally, to improve the engagement stability between the hook end of the elastic hook 501 and the slot 303, and to further reduce the wear of the elastic hook 501 and the upper outer sleeve 3, a fifth chamber 503 is provided inside the spring claw 5. The fifth chamber 503 is a strip-shaped structure that extends in a direction parallel to the axis of the spring claw 5 and is located inside the flow channel 502. The fifth chamber 503 and the flow channel 502 are connected. A piston rod 23 is inserted into the fifth chamber 503. The piston rod 23 extends in a direction parallel to the axis of the spring claw 5, and its left end forms a piston engagement with the fifth chamber 503. Its right end extends outward and penetrates the right end face of the spring claw 5. The piston rod 23 is connected to the spring claw 5 through a second elastic element. Under the action of the second elastic element, the piston rod... 23 can slide elastically along the axial direction, facilitating reset; the second elastic element can be set as a helical spring 24, which is inserted into the fifth chamber 503 and connected between the left end wall of the fifth chamber 503 and the left end of the piston rod 23; the adjusting ring 7 has a fixed sub-ring 701 and a sliding sub-ring 702 arranged coaxially. The fixed sub-ring 701 and the central tube 6 form a threaded engagement. The sliding sub-ring 702 can slide axially relative to the fixed sub-ring 701 and is fixedly connected to the right end of the piston rod 23, so that the piston rod 23 can drive the sliding sub-ring 702 to move synchronously; the sliding sub-ring 702 also forms a stop engagement with the inner side wall of all the elastic hooks 501; at this time, the swing fulcrum of the hook end of the elastic hook 501 is the right end of the sliding sub-ring 702.

[0048] During use, before the spring claw 5 moves, the liquid in the delivery channel 16 is filtered by the filter structure under the action of pressure difference, and then enters the fourth chamber 20 through the one-way valve 22 and is stored in the fourth chamber 20.

[0049] When the spring claw 5 moves, the volume of the fourth chamber 20 decreases and the pressure increases. Under the action of pressure difference, the liquid in the fourth chamber 20 passes through the flow channel 502 and enters the fifth chamber 503, pushing the piston rod 23 to move to the left. While compressing the helical spring 24, it simultaneously drives the sliding ring 702 to move to the left. At this time, because the swing fulcrum of the hook end of the elastic hook 501 moves to the left, the resistance encountered by the hook end of the elastic hook 501 when swinging is reduced, and the elastic restoring force generated after swinging is smaller. Therefore, when the hook end of the elastic hook 501 slides on the inner wall of the upper outer sleeve 3, the normal pressure and friction between it and the inner wall of the upper outer sleeve 3 are reduced, thereby further reducing the wear of the elastic hook 501 and the upper outer sleeve 3.

[0050] It should be noted that the movement of the sliding ring 702 can change the swing fulcrum of the hook end of the elastic hook 501, thereby changing the normal pressure and friction between the hook end of the elastic hook 501 and the groove 303. Therefore, when the spring claw 5 is in the first position, the adjusting ring 7 can be located closer to the hook end of the elastic hook 501, making the normal pressure and friction between the hook end of the elastic hook 501 and the groove 303 greater. This makes it more difficult for the hook end of the elastic hook 501 to disengage from the groove 303, thus improving the stability of the hydraulically controlled casing pressure connection and tubing blowout preventer when developing oil wells using the drag-type fracturing process. Subsequently, when the spring claw 5 moves, the movement of the sliding ring 702 can reduce the normal pressure and friction between the hook end of the elastic hook 501 and the groove 303, thereby reducing the wear of the elastic hook 501 and the upper outer sleeve 3.

[0051] Alternatively, the second elastic element can also be configured as a rubber block, spring sheet, or other structure that can reset the piston rod 23.

[0052] Optionally, to improve the reliability of the sliding ring 702, multiple fifth chambers 503 are provided, evenly arranged circumferentially and corresponding to the elastic hooks 501. Each fifth chamber 503 is equipped with a piston rod 23 and a helical spring 24. The sliding ring 702 is also fixedly connected to all the piston rods 23, so that the movement of the sliding ring 702 can be driven synchronously by all the piston rods 23.

[0053] The third embodiment of the present invention also provides a control system for a hydraulically controlled oil casing pressure connection and tubing blowout preventer, applied to a hydraulically controlled oil casing pressure connection and tubing blowout preventer. The control system for the hydraulically controlled oil casing pressure connection and tubing blowout preventer includes: The controller is configured to operate the hydraulic sleeve pressure connection and the tubing blowout preventer according to a preset program, which includes the following steps: S1. Lower the hydraulically controlled oil casing pressure connection and tubing blowout preventer and tubing to the preset position inside the oil well; S2. Fracturing fluid is delivered into the oil channel to develop the oil well through fracturing technology; S3. Increase the pressure of the fracturing fluid entering the third chamber 19. Under hydraulic action, the spring claw 5, the sliding sleeve 4, and the central tube 6 move as a whole closer to the upper connector 1. First, it moves from the first position to the second position. At this time, the elastic hook 501 and the upper outer sleeve 3 are engaged. The first chamber 17 is connected to the oil passage and the delivery passage 16, realizing the pressure connection between the oil and the casing. Then, it moves from the second position to the third position. At this time, the elastic hook 501 and the upper outer sleeve 3 are engaged. The second chamber 18 is connected to the delivery passage 16. The valve plate 12 laterally cuts off the delivery passage 16 to achieve the oil pipe blowout prevention. S4, drives the hydraulically controlled oil jacket pressure connection and the oil pipe blowout preventer and oil pipe to move upward; S5, drives the spring claw 5, the sliding sleeve 4 and the central tube 6 to reset as a whole; Specifically, the sliding sleeve 4 can be reset by installing a drive cylinder inside the upper connector 1. When the sliding sleeve 4 moves, it simultaneously drives the spring claw 5 and the central tube 6 to move, thereby realizing the overall reset of the spring claw 5, the sliding sleeve 4 and the central tube 6.

[0054] Understandably, the drive cylinder can be any of the following: hydraulic cylinder, pneumatic cylinder, or electric cylinder.

[0055] S6. Repeat S1-S5.

[0056] Specifically, segmented fracturing of oil wells can be achieved by repeating steps S1-S5.

[0057] Specifically, a controller is a device that generates operational control signals based on instruction opcodes and timing signals, instructing the hydraulically controlled casing pressure connection and the tubing blowout preventer and tubing to execute control commands. For example, a controller can be a central processing unit (CPU), a network processor (NP), a digital signal processor (DSP), a microprocessor, a microcontroller, a programmable logic device (PLD), or any combination thereof. A controller can also be other devices with processing capabilities, such as circuits, devices, or software modules.

[0058] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0059] The above embodiments are merely illustrative of several implementations of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the protection scope of the present invention.

Claims

1. A hydraulically controlled oil jacket pressure connection and oil pipe blowout preventer, characterized in that, The hydraulically controlled oil casing pressure connection and tubing blowout preventer is inserted into the tubing, forming an oil channel between them for receiving fracturing fluid from the outside. The hydraulically controlled oil casing pressure connection and tubing blowout preventer includes an upper connector; an upper outer sleeve is fitted onto the upper connector; a lower outer sleeve is fitted onto the upper outer sleeve; a lower connector is inserted inside the lower outer sleeve; a spring claw is inserted inside the upper outer sleeve; a sliding sleeve and a central tube are inserted inside the spring claw, arranged axially; a delivery channel is formed between the upper connector, sliding sleeve, central tube, and lower connector; a first chamber is formed between the central tube, spring claw, and upper outer sleeve, and the first chamber is connected to the delivery channel; multiple elastic hooks are provided on the spring claw, arranged circumferentially and all located within the first chamber, with the hook ends facing outwards and capable of engaging with the grooves on the upper outer sleeve; an adjusting ring is fitted onto the central tube, and the adjusting ring is located at the... The first chamber is axially slidable and can form a stop with all the elastic hooks. A second chamber is formed between the upper outer sleeve, the central tube, the lower outer sleeve, and the lower connector. A sealing sleeve is inserted in the second chamber, and a valve plate is elastically hinged on the sealing sleeve. Under the action of elasticity, the valve plate can form a stop with the central tube and can also cut off the conveying channel laterally. A third chamber is formed between the spring claw and the upper outer sleeve. The third chamber is connected to the oil channel, so that the spring claw can synchronously drive the sliding sleeve and the central tube to slide axially. Before sliding, it has a first position, at which time the elastic hook and the upper outer sleeve are engaged. After sliding, it has a second position and a third position in sequence. When it is in the second position, the elastic hook and the upper outer sleeve are engaged, and the first chamber is connected to the oil channel and the conveying channel. When it is in the third position, the elastic hook and the upper outer sleeve are engaged, the second chamber is connected to the conveying channel, and the valve plate cuts off the conveying channel laterally. A fourth chamber is formed between the upper connector, the upper outer sleeve, the sliding sleeve, and the spring claw. The fourth chamber is unidirectionally connected to the conveying channel, and the connection direction is from the conveying channel to the fourth chamber. A filter structure is provided at the connection point. A nozzle is opened on the hook end of the elastic hook, and the nozzle faces the upper outer sleeve. A flow channel is provided inside the spring claw and the elastic hook, and the flow channel connects the nozzle and the fourth chamber.

2. The hydraulically controlled oil jacket pressure connection and oil pipe blowout prevention tool according to claim 1, characterized in that, A valve seat is inserted between the upper outer sleeve and the central tube. The valve seat is fixedly connected to the upper outer sleeve, and the valve seat is slidably connected to the central tube. The second chamber is formed by the upper outer sleeve, the valve seat, the central tube, and the lower connector of the lower outer sleeve.

3. The hydraulically controlled oil jacket pressure connection and oil pipe blowout prevention tool according to claim 1, characterized in that, The valve plate is connected to the sealing sleeve via a first elastic element; the first elastic element is a torsion spring, and under the action of the torsion spring, the valve plate tends to rotate toward the side closer to the conveying channel.

4. The hydraulically controlled oil jacket pressure connection and oil pipe blowout prevention tool according to claim 1, characterized in that, The hook end of the elastic hook has a portion of its structure and a slot spaced apart, and is connected to the nozzle.

5. The hydraulically controlled oil jacket pressure connection and oil pipe blowout prevention tool according to claim 1, characterized in that, The inner wall of the outer jacket can completely seal the nozzle.

6. The hydraulically controlled oil jacket pressure connection and oil pipe blowout prevention tool according to claim 1, characterized in that, The spring claw has a fifth chamber inside, which is connected to the flow channel. A piston rod is inserted into the fifth chamber, and the piston rod and the fifth chamber form a piston fit and can slide elastically along the axial direction. The adjusting ring has a fixed sub-ring and a sliding sub-ring arranged coaxially. The sliding sub-ring is located on the outside and can slide axially relative to the fixed sub-ring and is fixedly connected to the piston rod.

7. The hydraulically controlled oil jacket pressure connection and oil pipe blowout prevention tool according to claim 6, characterized in that, The piston rod is connected to a spring claw via a second elastic element; the second elastic element is a coil spring.

8. The hydraulically controlled oil jacket pressure connection and oil pipe blowout prevention tool according to claim 1, characterized in that, There are multiple connections between the fourth chamber and the delivery channel. Each connection is unidirectional and each connection is equipped with a filter structure.

9. A control system for a hydraulically controlled oil jacket pressure connection and oil pipe blowout preventer, characterized in that, The control system of the hydraulically controlled oil casing pressure connection and tubing blowout preventer, as described in any one of claims 1 to 8, comprises: The controller is configured to operate the hydraulic sleeve pressure connection and the tubing blowout preventer according to a preset program, which includes the following steps: S1. Lower the hydraulically controlled oil casing pressure connection and tubing blowout preventer and tubing to the preset position inside the oil well; S2. Fracturing fluid is delivered into the oil channel to develop the oil well through fracturing technology; S3. Increase the pressure of the fracturing fluid entering the third chamber. Under hydraulic action, the spring claw, sliding sleeve, and central tube move as a whole closer to the upper joint, and first move from the first position to the second position. At this time, the elastic hook and the upper outer sleeve engage, and the first chamber connects the oil passage and the delivery passage, realizing the pressure connection between the oil and casing. Then, it moves from the second position to the third position. At this time, the elastic hook and the upper outer sleeve engage, and the second chamber connects to the delivery passage. The valve plate laterally cuts off the delivery passage, realizing the oil pipe blowout prevention. S4, drives the hydraulically controlled oil jacket pressure connection and the oil pipe blowout preventer and oil pipe to move upward; S5, drives the spring claw, sliding sleeve and central tube to reset as a whole; S6. Repeat S1-S5.

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