Hydraulic control valve and screw clamp launching safety protection valve

Abstract

The hydraulic control valve, the screw clamp launching safety protection valve, the upper hydraulic control valve and the lower hydraulic control valve can respectively and independently control the opening and closing of internal channels; the upper end of the upper hydraulic control valve is connected with the screw clamp transmitting device, and the lower end is communicated with the upper end of the lower hydraulic control valve; the lower end of the lower hydraulic control valve is connected with the upper end of the lower joint; the lower end of the lower joint is connected with the upper end of the Christmas tree pipe column; an upper hydraulic control valve is firstly opened, and then a screw clamp is launched; and when the screw clamp penetrates through the valve plate of the upper hydraulic control valve, the upper hydraulic control valve is closed, the lower hydraulic control valve is opened at the same time, and the screw clamp continues to move downwards and is located on the target sliding sleeve. The upper hydraulic control valve and the lower hydraulic control valve which are independently controlled to be opened and closed are connected in series, and a double-valve-plate structure is formed on a downward passage of the screw clamp, so that one valve plate is always in a closed state in the downward entering process of the screw clamp, potential safety hazards caused by upward surging of fluid with pressure in a shaft are avoided, and the safety of the screw clamp in the launching process is ensured.

Description

Technical Field

[0001] This utility model relates to the field of oil and gas field development tools, specifically a hydraulic control valve and a screw-locking safety protection valve for fracturing processes. Background Technology

[0002] To enhance production and improve extraction efficiency, most cased horizontal wells in unconventional reservoirs currently require multi-stage fracturing. Two main methods are commonly used: multi-stage sliding sleeve fracturing and pumped bridge plug fracturing. Conventional multi-stage fracturing with sliding sleeves can only open one sleeve at a time with each ball drop, and the inner diameter of the ball seat decreases progressively, limiting the number of sleeves that can be used and thus restricting the fracturing length of the horizontal section, impacting oil and gas extraction efficiency. Pumped bridge plug fracturing, a mature and frequently used multi-stage fracturing method, does not limit the fracturing length and can meet the high-displacement requirements of fracturing processes. However, it has disadvantages such as longer operation time, more complex construction process, and the need for more supporting equipment.

[0003] There is also an unlimited-stage fracturing sliding sleeve system that can overcome the shortcomings of current traditional fracturing processes. It not only allows for unlimited fracturing stages and full-bore sliding sleeve operation, but also enables continuous operation, reducing the scale of operations and significantly improving extraction efficiency. The basic fracturing process is as follows: First, the fracturing sliding sleeve is inserted into the well along with the casing. Then, a screw clamp is deployed and pumped into the wellbore. The screw clamp then descends through the non-target sliding sleeve and finally locks itself into the target sliding sleeve below. The screw clamp is designed to be one-to-one matched with the downhole fracturing sliding sleeve. Next, a ball is dropped and pressure is applied to shear the sliding sleeve's shear pins. The screw clamp moves down with the inner sleeve, the sliding sleeve opens, and fracturing operations are performed—this cyclical operation allows for unlimited-stage fracturing. Finally, all the soluble balls dropped are dissolved, achieving full-bore operation inside the tool.

[0004] However, this fracturing system also has safety issues: since the wellhead is usually pressurized, the upward flow of pressurized fluid inside the wellbore during the deployment of the screw clamp can affect its deployment and pose a safety hazard. Without a robust safety barrier within the wellbore, it is difficult to guarantee the safety of the screw clamp deployment process.

[0005] Some existing technologies employ a dual-valve plate structure for downhole safety valves. For example, CN201074502Y discloses a "Dual-Valve Plate Downhole Safety Valve," where the two valve plates are interchangeable. If the upper valve plate fails, a locking tool must be inserted to permanently open it, after which the lower valve plate takes over. Another example is CN110173233A, which discloses a "Downhole Safety Valve." While it doesn't require a locking tool, it still requires the connection of the upper and lower central pipes to keep the upper valve plate normally open before the lower valve plate takes over its function. The purpose of these solutions is to ensure that at least one valve plate is operational; the two valve plates are interchangeable and serve different technical purposes. Furthermore, they cannot be used simultaneously or alternately, and none of them effectively protect the screw-locking mechanism. Summary of the Invention

[0006] This invention aims to solve the safety problems of hydraulic control valves and screw-clamp launchers in the above-mentioned infinite-stage fracturing sliding sleeve system, and provides a screw-clamp launcher safety protection valve.

[0007] To achieve the above objectives, the technical solution adopted by this utility model includes a hydraulic control valve, comprising a hydraulic control chamber tube, a spring cylinder, and a closing mechanism connected in sequence. The spring cylinder has an axially movable flow tube inside, and the upper and lower ends of the flow tube are respectively connected to the hydraulic control chamber tube and the closing mechanism. The outer wall of the flow tube and the inner wall of the spring cylinder are connected by a power spring.

[0008] The upper end of the flow tube is connected to a rod piston, which is inserted upward into the piston hole at the lower end of the hydraulic control chamber tube. The outer wall of the hydraulic control chamber tube is provided with a hydraulic control connection interface to connect to the piston hole.

[0009] When pressure is applied to the self-hydraulic control interface, the rod piston is pressed down and pushes the flow tube down, and the lower end of the flow tube opens the valve plate of the closing mechanism.

[0010] The piston bore has a tapered sealing surface at the top, the rod piston has a spherical sealing surface at the top, or the rod piston has an upper piston cap at the top, with the upper end of the upper piston cap having a spherical sealing surface, and the two form a sealing fit.

[0011] A stop plug is installed at the opening at the lower end of the piston bore.

[0012] The rod piston has a mud scraper ring on its outer wall.

[0013] A sealing assembly is provided between the outer wall of the rod piston and the inner wall of the piston bore.

[0014] The lower end of the rod piston is equipped with a lower piston cap, which is connected to the upper end of the flow tube.

[0015] The side wall of the hydraulic control chamber is provided with a through overflow port or pressure regulation port.

[0016] The closing mechanism includes a valve seat, a valve plate, a pin, and a torsion spring. The upper end of the valve seat is connected to the lower end of the spring sleeve, and the lower end of the valve seat is provided with a valve plate frame. The valve plate is connected to the valve plate frame through the pin. The helical part of the torsion spring is fitted onto the pin, with one end arm mounted on the valve plate frame and the other end arm pressing against the lower end face of the valve plate.

[0017] The upper end of the dynamic spring is located on the protruding stepped surface of the outer wall of the upper end of the flow tube; its lower end rests on the stepped surface of the inner wall of the lower end of the spring cylinder, or the lower end of the flow tube is connected to the upper end face of the thrust bearing, and the lower end face of the thrust bearing rests on the stepped surface of the inner wall of the lower end of the spring cylinder.

[0018] This utility model also provides a screw-launch safety protection valve, including an upper hydraulic control valve, a lower hydraulic control valve, and a lower connector; the upper hydraulic control valve and the lower hydraulic control valve can independently control the opening and closing of their internal channels, forming a double valve plate structure on the downward passage of the screw; wherein, the upper end of the upper hydraulic control valve is connected to the screw-launch device, and its lower end is connected to the upper end of the lower hydraulic control valve; the lower end of the lower hydraulic control valve is connected to the upper end of the lower connector, and the lower end of the lower connector is connected to the upper end of the wellhead tubing;

[0019] First, open the upper hydraulic control valve, then launch the screw clamp; when the screw clamp passes through the valve plate of the upper hydraulic control valve, close the upper hydraulic control valve and simultaneously open the lower hydraulic control valve, and the screw clamp continues to descend and sits on the target sliding sleeve.

[0020] Wherein, the upper hydraulic control valve and / or the lower hydraulic control valve are either of the hydraulic control valves described above.

[0021] Compared with the existing technology, this utility model uses an upper hydraulic control valve and a lower hydraulic control valve connected in series to independently control the opening and closing of the screw clamp, forming a double valve plate structure in the downward passage of the screw clamp. This ensures that one valve plate is always in a closed state during the screw clamp's lowering process, avoiding the safety hazards caused by the upward surge of pressurized fluid in the wellbore, and also ensuring the safety of the screw clamp's launching process. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of an embodiment of the present utility model;

[0023] Figure 2 This is a cross-sectional view of the upper hydraulic control valve;

[0024] Figure 3 for Figure 2 A magnified view of part B, where a rod-type piston is located;

[0025] Figure 4 This is a cross-sectional view of the lower hydraulic control valve;

[0026] Referring to the attached diagram, 1-Upper hydraulic control chamber tube, 2-Upper piston cap, 3-Sealing assembly, 4-Scraper ring, 5-Piston rod, 6-Stop plug, 7-Lower piston cap, 8-Sealing ring, 9-Flow tube, 10-Power spring, 11-Spring sleeve, 12-Thrust bearing, 14-Valve seat, 15-Connecting sleeve, 16-Valve plate bracket, 17-Pin, 18-Torsion spring, 19-Valve plate, 20-Lower hydraulic control chamber tube, 21-Lower connector, J-Upper hydraulic control connection interface, H-Lower hydraulic control connection interface, K-Overflow interface, N-Pressure regulating interface. Detailed Implementation

[0027] The present invention will now be further described with reference to the accompanying drawings. For ease of description, the direction pointing downwards along the central axis of the flow tube to the lower connector is referred to as "downwards," and the opposite direction is referred to as "upwards."

[0028] See Figures 1 to 4 , Figures 1 to 4 This illustration showcases an embodiment of the present invention: a screw-clip launch safety protection valve, which, from top to bottom, is mainly composed of three isomorphically connected parts: an upper hydraulic control valve, a lower hydraulic control valve, and a lower connector. The upper end of the screw-clip launch safety protection valve is directly connected to the screw-clip launch device at the top, and the lower end is connected to the production tree tubing below it via a flange connection structure. The upper and lower hydraulic control valves are connected in series, forming a double-valve plate structure design in the downward path after the screw-clip launch.

[0029] Among them, see Figure 2 The upper hydraulic control valve mainly consists of an upper hydraulic control chamber tube, a rod piston, a flow tube, a power spring, a spring cylinder, and a closing mechanism. The lower outer wall of the upper hydraulic control chamber tube is directly threaded to the upper inner wall of the spring cylinder; and a sealing ring is provided at the connection to form a sealing structure.

[0030] Preferably, the side wall of the hydraulic control chamber is provided with a through overflow port K for adjusting its internal and external pressure. The flow tube is located inside the spring cylinder and can move up and down along its central axis. The upper and lower ends of the flow tube are connected to the hydraulic control chamber and the closing mechanism, respectively, forming a passage for the screw to descend. One side of the upper end face of the flow tube is connected to the lower end of a rod-type piston, the entire piston body of which is inserted upwards into the piston hole at the lower end of the hydraulic control chamber; the piston hole is located on an eccentric side inside the upper hydraulic control chamber, and its lower opening is located on the lower end face of the upper hydraulic control chamber. Furthermore, the outer wall of the hydraulic control chamber is also provided with an upper hydraulic control connection port J, which is radially arranged and connects its outer wall to the upper end of the piston hole.

[0031] As a preferred option, see Figure 3 The piston bore has a tapered sealing surface at the bottom of its upper end, and the rod piston has an upper piston cap at its upper end. The upper end of the upper piston cap has a spherical sealing surface (i.e., the rod piston has a spherical sealing surface at its upper end), and the two form a sealing fit.

[0032] Preferably, the outer wall of the rod piston is provided with a mud scraper ring to remove mud and keep the piston bore clean.

[0033] Preferably, a sealing assembly is provided between the upper outer wall of the rod piston and the inner wall of the piston bore to further maintain the seal.

[0034] Preferably, the lower end of the rod piston is provided with a lower piston cap, which is connected to the upper end of the flow tube by a snap-fit ​​structure.

[0035] Preferably, the piston bore opening is designed with internal threads to accommodate a stop plug for limiting the position of the rod-type piston. See also Figure 2 The dynamic spring is fitted onto the outer wall of the flow tube. Its upper end rests on the lower end face of the convex stepped surface of the upper outer wall of the flow tube, and its lower end rests on the upper end face of the thrust bearing. Simultaneously, the lower end face of the thrust bearing rests on the stepped surface of the lower inner wall of the spring sleeve. When the flow tube is pressed downwards, the dynamic spring is compressed; when the pressure above the flow tube is removed, the dynamic spring releases its elastic force, causing the flow tube to return to its original position. See also... Figure 2 The closing mechanism is a combined mechanism, mainly composed of a valve seat, connecting sleeve, valve plate bracket, pin, torsion spring, and valve plate. The upper end of the closing mechanism is directly connected to the internal thread of the lower end of the spring cylinder via the valve seat; a sealing ring is designed at the connection point to form a sealing structure. The valve plate bracket is connected to the valve seat via the connecting sleeve, and the valve plate is connected to the valve plate bracket via the pin. The helical part of the torsion spring is fitted onto the pin, with one end arm mounted on the valve plate bracket and the other end arm pressing against the lower end face of the valve plate; initially, the valve plate is in the closed state. When the flow tube is pressurized downwards, its lower end pushes the valve plate downwards, opening the passage; when the flow tube moves upwards, its lower end moves upwards accordingly, and the compressed torsion spring releases its elastic force to close the valve plate.

[0036] See Figure 4 The lower hydraulic control valve has a structure that is basically the same as the upper hydraulic control valve, except that the upper part of the upper hydraulic control valve is the upper hydraulic control chamber tube, which is directly connected to the screw-launch device at the top. The upper part of the lower hydraulic control valve, on the other hand, is the lower hydraulic control chamber tube, which is directly connected to the lower end of the spring cylinder of the upper hydraulic control valve; and a sealing ring is provided at the connection. Therefore, the lower hydraulic control valve differs from the upper hydraulic control valve only in the connection structure of its upper part; the other structures are the same, so they will not be described in detail. In addition, the side wall of the lower hydraulic control chamber tube is also designed with a lower hydraulic control connection interface H, used to connect to the upper end of the rod piston of the lower hydraulic control valve; and a pressure regulating interface N.

[0037] Located at the bottom of this embodiment is the lower connector. The upper end of the lower connector is threaded to the lower end of the spring sleeve at the lower end of the lower hydraulic control valve; and sealing rings are provided at the connection points to form a sealing structure. In addition, the lower end of the lower connector adopts a flange connection structure, and the entire screw-clamp launch safety protection valve is connected to the lower Christmas tree tubing through this flange structure.

[0038] See Figure 1 After installation, the screw-operated safety valve is in a vertical position, and both valve plates (upper and lower) are closed. When fracturing begins, pressure is applied through the upper hydraulic control connection interface J, pushing the rod piston downwards, which in turn pushes the flow tube downwards and simultaneously compresses the power spring. The hydraulic pressure continues to increase until the flow tube descends to fully open the upper valve plate belonging to the upper hydraulic control valve.

[0039] At this point, a screw chuck is inserted from the screw chuck launching device at the top of the embodiment and passes downwards along the passage through the already opened upper valve plate. When the screw chuck stops in the middle area between the upper and lower valve plates, the hydraulic control pressure applied at the upper end is released to close the upper valve plate; then, pressure continues to be applied through the lower hydraulic control connection interface H to open the lower valve plate belonging to the lower hydraulic control valve in the same manner. At the same time, the screw chuck continues to fall as the second lower valve plate opens, passes through the downhole non-target sliding sleeve, and settles in the corresponding target sliding sleeve below to complete the locking. Thus, the first screw chuck launch is completed.

[0040] The screw clamps act as ball seats downhole, facilitating subsequent ball-dropping and pressurization to open the sliding sleeve for fracturing. Similarly, subsequent screw clamps can be smoothly lowered to the target sliding sleeve downhole and locked in place following the same procedure, allowing for the sequential completion of subsequent fracturing operations.

[0041] Furthermore, when the lower valve plate cannot be opened smoothly by hydraulic control due to excessive pressure at its lower end, a balancing pressure can be applied to the inside of the protection valve through the pressure regulating port N on the side wall of the lower hydraulic control chamber to achieve smooth opening of the lower valve plate. Similarly, when there is excessive pressure at the lower end of the upper valve plate and it cannot be opened by hydraulic control pressure, the pressure at the lower end of the upper valve plate can be released through the overflow port K, and then hydraulic control pressure can be applied to open it.

[0042] In summary, this embodiment fully considers the actual situation of pressure at the wellhead, ensuring that the valve plate can be opened smoothly under pressure. Moreover, the upper and lower double valve plate structure design ensures that one valve plate is always closed during the screw drive insertion process, avoiding the safety hazards caused by the upward surge of pressurized fluid in the wellbore and ensuring the safety of the screw drive launch process.

[0043] The embodiments of this utility model have been described above with reference to the accompanying drawings and examples. The structures given in the embodiments do not constitute a limitation on this utility model. Those skilled in the art can make adjustments as needed, and various modifications or variations within the scope of the appended claims are all within the scope of protection.

Claims

1. A hydraulic control valve, characterized in that: It includes a hydraulically controlled cavity tube, a spring cylinder, and a closing mechanism connected in sequence. The spring cylinder has an axially movable flow tube inside, and the upper and lower ends of the flow tube are respectively connected to the hydraulically controlled cavity tube and the closing mechanism. The outer wall of the flow tube and the inner wall of the spring cylinder are connected by a power spring. The upper end of the flow tube is connected to a rod piston, which is inserted upward into the piston hole at the lower end of the hydraulic control chamber tube. The outer wall of the hydraulic control chamber tube is provided with a hydraulic control connection interface to connect to the piston hole. When pressure is applied to the self-hydraulic control interface, the rod piston is pressed down and pushes the flow tube down, and the lower end of the flow tube opens the valve plate of the closing mechanism.

2. The hydraulic control valve according to claim 1, characterized in that: The upper end of the piston bore is provided with a tapered sealing surface, the upper end of the rod piston is provided with a spherical sealing surface, or the upper end of the rod piston is provided with an upper piston cap, the upper end of the upper piston cap is provided with a spherical sealing surface, and the two form a sealing fit. And / or, a stop plug is installed at the opening at the lower end of the piston bore.

3. The hydraulic control valve according to claim 2, characterized in that: The outer wall of the rod piston is equipped with a mud scraper ring; And / or, a sealing assembly is provided between the outer wall of the rod piston and the inner wall of the piston bore; And / or, the lower end of the rod piston is provided with a lower piston cap, which is connected to the upper end of the flow tube.

4. The hydraulic control valve according to claim 1, characterized in that: The side wall of the hydraulic control chamber is provided with a through overflow port or pressure regulating port.

5. The hydraulic control valve according to claim 1, characterized in that: The closing mechanism includes a valve seat, a valve plate, a pin, and a torsion spring. The upper end of the valve seat is connected to the lower end of the spring sleeve, and the lower end of the valve seat is provided with a valve plate bracket. The valve plate is connected to the valve plate bracket through the pin. The helical part of the torsion spring is fitted onto the pin, with one end arm mounted on the valve plate bracket and the other end arm pressing against the lower end face of the valve plate.

6. The hydraulic control valve according to claim 1, characterized in that: The upper end of the dynamic spring is located on the protruding stepped surface of the outer wall of the upper end of the flow tube; its lower end rests on the stepped surface of the inner wall of the lower end of the spring cylinder, or the lower end of the flow tube is connected to the upper end face of the thrust bearing, and the lower end face of the thrust bearing rests on the stepped surface of the inner wall of the lower end of the spring cylinder.

7. A screw-type launch safety protection valve, characterized in that: It includes an upper hydraulic control valve, a lower hydraulic control valve, and a lower connector; the upper hydraulic control valve and / or the lower hydraulic control valve are hydraulic control valves as described in any one of claims 1-6, and the upper hydraulic control valve and the lower hydraulic control valve can independently control the opening and closing of their internal channels; The upper end of the upper hydraulic control valve is connected to the screw-clip launching device, and its lower end is connected to the upper end of the lower hydraulic control valve. The lower end of the lower hydraulic control valve is connected to the upper end of the lower connector, and the lower end of the lower connector is connected to the upper end of the Christmas tree tubing. First, open the upper hydraulic control valve, then launch the screw clamp; when the screw clamp passes through the valve plate of the upper hydraulic control valve, close the upper hydraulic control valve and simultaneously open the lower hydraulic control valve, and the screw clamp continues to descend and sits on the target sliding sleeve.

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