A 140mpa gas production fracturing wellhead device

Abstract

The application relates to the field of fracturing wellhead devices, in particular to a 140MPA gas production fracturing wellhead device, which comprises a wellhead body, the wellhead body is a basic bearing structure for high-pressure gas production fracturing operation; an oil pipe is connected to the outer end surface of the wellhead body and is used for conveying fracturing fluid; a valve body is arranged at the end of the oil pipe away from the wellhead body and is used for controlling the on-off of the fracturing fluid; a valve pipe, a flange plate and a driving unit, the valve pipe is arranged at the top of the valve body and is in communication with the inside of the valve body; the flange plate is fixedly connected to the top of the valve pipe through bolts and is used for sealing the top end of the valve pipe; the driving unit is arranged at the top of the flange plate and provides driving force; the 140MPA gas production fracturing wellhead device immediately outputs thrust force through the driving unit, drives the flow-stopping mechanism to quickly drop along the axial direction, rapidly cuts off the fracturing fluid channel, has fast response speed and can effectively avoid safety risks such as wellhead leakage and component damage caused by high pressure.

Description

Technical Field

[0001] This invention relates to the field of fracturing wellhead equipment technology, specifically a 140MPA gas production fracturing wellhead equipment. Background Technology

[0002] In shale gas extraction, fracturing is the core step for efficient extraction. High-pressure pumps inject fracturing fluid (a mixture of water, sand, and chemical additives) into the shale reservoir at 100-140 MPa, creating artificial fractures and allowing shale gas to flow out smoothly. Wellhead valves, as key equipment for fracturing fluid delivery and control, must perform three core functions: first, emergency shutdown, cutting off the fracturing fluid channel within 3 seconds in case of a sudden increase in formation pressure (exceeding the safety threshold of 140 MPa) or equipment failure, to prevent wellhead overpressure and potential safety accidents; second, flow regulation, dynamically adjusting the fracturing fluid flow rate based on the shale gas reservoir permeability to ensure the fracture morphology meets design requirements; and third, high-pressure sealing, maintaining a leak-free seal under long-term high pressure (100-140 MPa) and high flow rate (fracturing fluid velocity can reach 10-20 m / s), preventing fracturing fluid waste and environmental pollution.

[0003] The existing valve drive structure cannot meet the requirements of "rapid shutdown" and "fine adjustment", resulting in both safety risks and operational errors: First, the single hydraulic drive results in slow emergency shutdown response: Traditional valves rely solely on hydraulic cylinder drive, and the shutdown process must overcome the friction of the threaded pair and the resistance of the high-pressure medium, with a shutdown time of 5-8 seconds. When the formation pressure suddenly rises to 145MPa (exceeding the safety threshold), the delayed shutdown will cause the wellhead pressure to continue to rise, which may lead to safety accidents such as wellhead equipment rupture and fracturing fluid injection. At the same time, the hydraulic system is susceptible to low temperature, which increases the viscosity of the hydraulic oil and further prolongs the shutdown time. Summary of the Invention

[0004] The present invention provides a 140MPA gas fracturing wellhead device to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a 140MPA gas production fracturing wellhead device, comprising a wellhead body, wherein the wellhead body is the basic load-bearing structure for high-pressure gas production fracturing operations; an oil pipe is connected to the outer end face of the wellhead body for transporting fracturing fluid; a valve body is provided at the end of the oil pipe away from the wellhead body for controlling the flow of fracturing fluid;

[0006] The valve tube, flange, and drive unit are provided. The valve tube is located on the top of the valve body and communicates with the interior of the valve body. The flange is fixedly connected to the top of the valve tube by bolts and is used to seal the top of the valve tube. The drive unit is located on the top of the flange and provides driving force.

[0007] A flow-stopping mechanism is provided inside the valve tube and can move axially along the valve tube to realize the delivery control and flow-stopping sealing of fracturing fluid in the valve body;

[0008] A switching mechanism is provided inside the valve tube and above the flow-stopping mechanism. It is used to drive the flow-stopping mechanism to rise and fall and to switch the control mode.

[0009] The switching mechanism includes a drive rod, which is fixedly installed at the center of the flange. The top end of the drive rod is connected to the output end of the drive unit via a coupling. An internal sliding member is fixedly connected to the outside of the drive rod. The external side of the internal sliding member is slidably adapted to a limited slide rail, which is fixedly connected to the inner wall of the valve pipe.

[0010] Preferably, a wheel is connected to the outer side of the built-in sliding member via a bearing, and the wheel can rotate relative to the built-in sliding member;

[0011] A threaded valve stem is threadedly connected to the center of the wheel. The threaded valve stem extends along the axial direction of the wheel, and the bottom end of the threaded valve stem is fixedly connected to the flow-stopping mechanism.

[0012] Preferably, a first electric push rod is fixedly installed inside the drive rod, and a limit rod is fixedly connected to the output end of the first electric push rod at its bottom.

[0013] The limiting rod is inserted into the preset limiting hole on the top of the wheel. When the limiting rod is inserted, it restricts the rotation of the wheel, so that the drive rod directly drives the wheel, the threaded valve stem and the flow stop mechanism to rise and fall synchronously.

[0014] Preferably, a protective sleeve is fixedly installed on the outside of the valve tube, and a servo motor is fixedly installed inside the protective sleeve;

[0015] A first gear is fixedly connected to the outer side of the output end of the servo motor. A second gear meshes with the outer side of the first gear. The second gear is fixedly connected to the outer side of the wheel. The servo motor drives the wheel to rotate through gear transmission, thereby indirectly driving the threaded valve stem.

[0016] Preferably, a trapezoidal block is fixedly installed in the center of the valve body, the trapezoidal block has a trapezoidal cross-section and its inner wall is an inclined sealing surface;

[0017] When the flow-stopping mechanism descends to the flow-stopping position, it comes into contact with the inclined sealing surface of the trapezoidal block. The pressure is increased by the pressure of the inclined surface, which improves the flow-stopping and sealing performance of the fracturing fluid.

[0018] Preferably, the flow-stopping mechanism includes a connecting block, the top of which is fixedly connected to the threaded valve stem, a valve is fixedly installed at the bottom of the connecting block, a reducing rod is fixedly installed at the center of the valve, a first universal joint seat is fixedly installed at the end of the reducing rod away from the valve, and a drain valve is fixedly connected at the end of the first universal joint seat away from the reducing rod.

[0019] The variable diameter rod is fixedly connected to the ball joint inside the No. 1 universal joint seat.

[0020] Preferably, a hollow column is fixedly installed inside the valve, and a reset telescopic rod is slidably adapted inside the hollow column. A second universal joint seat is fixedly installed at the end of the reset telescopic rod away from the hollow column, and the end of the second universal joint seat away from the reset telescopic rod is fixedly connected to the vent valve.

[0021] The reset telescopic rod is fixedly connected to the ball joint inside the No. 2 universal joint seat.

[0022] Preferably, a groove is formed inside the hollow column, and a fixing ring is fixedly installed inside the groove. The fixing ring is used to limit the movement of the reset telescopic rod.

[0023] The first groove is fitted with a sliding folding rod. The end of the folding rod away from the first groove is pressed against the outer side of the reset telescopic rod. A reset spring is fixedly connected to the outer side of the folding rod. The end of the reset spring away from the folding rod is fixedly connected to the inner wall of the first groove.

[0024] Preferably, a push post is slidably adapted to the inner end of the hollow column away from the reset telescopic rod, and a second fixing ring is fixedly connected to the end of the push post away from the hollow column. A central disk is slidably adapted to the inner side of the second fixing ring, and a wedge is fixedly connected to the outer side of the central disk. The outer side of the wedge is compressively adapted to the trapezoidal block.

[0025] A block is fixedly connected to the outer side of the central disk.

[0026] Preferably, a second groove is provided on the outer side of the push column, a sliding ring is slidably adapted inside the second groove, an external rail is fixedly connected to both ends of the sliding ring, a second magnetic block is fixedly installed inside the external rail, a slide bar is slidably adapted inside the external rail, and a first magnetic block is fixedly connected to the outer side of the slide bar.

[0027] The first and second magnetic blocks have a repulsive relationship, and the outer side of the slider is squeezed and adapted to the block.

[0028] Compared with the prior art, the beneficial effects of the present invention are:

[0029] 1. The device features a "direct drive" emergency shut-in mode. When the formation pressure exceeds the 140MPa safety threshold, the limit rod can be quickly inserted into the wheel to lock it. The drive unit immediately outputs thrust, driving the flow-stopping mechanism to descend rapidly along the axial direction, quickly cutting off the fracturing fluid channel. The entire process requires no complex transmission conversion, has a fast response speed, and can effectively avoid safety risks such as wellhead leakage and component damage caused by high pressure, providing reliable emergency protection for shale gas high-pressure fracturing operations.

[0030] 2. The device achieves fine-tuning of flow rate through an "indirect drive" mode. A servo motor drives a wheel to rotate slowly via gear transmission. The trapezoidal thread converts the rotational motion into axial movement of the flow-stopping mechanism, allowing precise adjustment of the gap between the flow-stopping mechanism and the valve body channel. This minimizes errors in scenarios such as reducing the fracturing fluid flow rate from 55 cubic meters per hour to 35 cubic meters per hour. This precise adjustment capability adapts to the permeability differences of different shale gas layers, optimizing fracturing fluid injection effects and improving shale gas extraction efficiency. Similarly, if either the "direct drive" or "indirect drive" mode malfunctions, the drive method can be switched to allow subsequent operations to continue.

[0031] 3. The device employs a dual design of "inclined surface compression sealing + angle compensation." The trapezoidal block and the 25° inclined sealing surface of the bleed valve generate a sealing pressure of 210MPa under axial thrust, achieving initial high-pressure sealing. Simultaneously, the universal joint seat allows the bleed valve to automatically adjust its angle, ensuring complete sealing surface contact without local gaps even with installation coaxiality errors or minor component deformation. The combination of a 160MPa high-pressure metal spiral wound gasket and a copper gasket further strengthens the connection seal, completely eliminating fracturing fluid leakage and ensuring a clean working environment and equipment safety.

[0032] 4. The device employs a multi-layered buffering system comprised of magnetic repulsion and the elastic force of the return spring. When the sealing surface is subjected to high-pressure impact, the sliding bar overcomes the magnetic repulsion and moves, while the push rod compresses the return spring, and the elastic reaction force buffers most of the impact force. Simultaneously, the elastic support of multiple sets of return telescopic rods allows the vent valve to adaptively deflect towards the high-pressure side, balancing the pressure distribution. This buffering design significantly reduces the impact damage of high-pressure fracturing fluid on core components such as the sealing surface and valve stem, extending the overall service life of the device and reducing subsequent maintenance costs. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the external structure of a 140MPA gas fracturing wellhead device according to the present invention.

[0034] Figure 2 This is a cross-sectional view of the valve body of the present invention.

[0035] Figure 3 This is a cross-sectional view of the control mechanism of the present invention.

[0036] Figure 4 This is a schematic diagram of the trapezoidal block in the switching mechanism of the present invention.

[0037] Figure 5 This is a schematic diagram of the flow-stopping mechanism of the present invention.

[0038] Figure 6 This is a front view schematic diagram of the flow-stopping mechanism of the present invention.

[0039] Figure 7 This is a cross-sectional view of the valve in the flow-stopping mechanism of the present invention.

[0040] Figure 8 This is a cross-sectional view of the central disc in the flow-stopping mechanism of the present invention.

[0041] Figure 9 This is a cross-sectional enlarged structural schematic diagram of the push column in the flow-stopping mechanism of the present invention.

[0042] Figure 10 This is a schematic diagram of the structure of the block in the flow-stopping mechanism of the present invention.

[0043] Figure 11 This is a cross-sectional enlarged structural diagram of the external rail in the flow-stopping mechanism of the present invention.

[0044] In the picture:

[0045] 1. Wellhead body;

[0046] 2. Oil pipe;

[0047] 3. Valve body;

[0048] 4. Valve pipe;

[0049] 5. Flow control mechanism; 51. Connecting block; 52. Valve; 53. Variable diameter rod; 54. No. 1 universal joint seat; 55. Drain valve; 56. Hollow column; 57. Return telescopic rod; 58. No. 2 universal joint seat; 59. No. 1 slot; 50. No. 1 fixing ring; 501. Folding rod; 502. Return spring; 503. Push column; 504. No. 2 slot; 505. Slip ring; 506. No. 2 fixing ring; 507. External rail; 508. No. 1 magnetic block; 509. No. 2 magnetic block; 500. Sliding bar; 50A. Square block; 50B. Center plate; 50C. Wedge block;

[0050] 6. Control mechanism; 61. Drive rod; 62. Built-in sliding component; 63. Wheel; 64. Threaded valve stem; 65. Electric push rod No. 1; 66. Limit rod; 67. Protective sleeve; 68. Servo motor; 69. Gear No. 1; 60. Gear No. 2; 601. Limiting rail; 602. Trapezoidal block;

[0051] 7. Drive unit;

[0052] 8. Flange. Detailed Implementation

[0053] The present invention will now be further described with reference to the accompanying drawings and specific embodiments. It should be noted that, without conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments. It should be understood that the described embodiments are merely some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0054] Please see Figures 1 to 11 The present invention provides a technical solution: Example 1

[0055] like Figure 1 , Figure 2 and Figure 3 As shown, the wellhead body 1 serves as an integral load-bearing structure. Its outer end face is sealed to the tubing 2 via flange bolts. A metal spiral wound gasket with a pressure resistance of 160MPa is installed on the flange face to prevent fracturing fluid leakage. The end of the tubing 2 away from the wellhead body 1 is also connected to the inlet end of the valve body 3 via flange bolts, forming a fracturing fluid delivery channel. The top of the valve body 3 is fixed to the valve tube 4 by welding external radial reinforcement bolts. The weld is inspected by non-destructive testing to ensure no risk of cracking under high pressure. The top of the valve tube 4 is fixed to the flange 8 by circumferentially distributed high-strength bolts. A stepped hole is opened in the center of the flange 8, and the drive rod 61 is slidably installed inside. In addition, a double-layer sealing ring is used to seal the gap between the drive rod 61 and the stepped hole.

[0056] The top of the drive rod 61 is connected to the drive unit 7 via a flexible coupling. The drive unit 7 uses a hydraulic drive motor with an output thrust ≥80kN. The drive rod 61 is fixed to the outer side by a key connection with an internal sliding member 62. The internal sliding member 62 is an annular structure with a rectangular guide groove on its outer side. It slides and adapts to the sliding rail 601 fixed to the inner wall of the valve pipe 4 by welding. The clearance between the guide groove and the sliding rail 601 is ≤0.1mm, ensuring that the drive rod 61 moves only axially and has no radial offset.

[0057] The inner sliding member 62 is connected to the wheel 63 by a deep groove ball bearing with a dust cover. The wheel 63 has bearings on both the upper and lower sides, which allow the wheel 63 to rotate flexibly relative to the inner sliding member 62, while isolating dust and impurities in the fracturing operation. The wheel 63 has a trapezoidal internal thread hole in the center, which is precisely matched with the trapezoidal external thread of the threaded valve stem 64. The bottom end of the threaded valve stem 64 is fixed to the connecting block 51 of the flow control mechanism 5 by flange bolts. A copper gasket is added to the flange face to enhance the connection sealing.

[0058] Direct drive mode: The first electric push rod 65 is fixed inside the drive rod 61 by the push rod seat bolt, and the limit rod 66 is welded to the output end of the push rod; the top of the wheel 63 has a pre-set limit hole that matches the limit rod 66. After the limit rod 66 is inserted, the gap between the limit rod 66 and the limit hole is ≤0.2mm, which can completely restrict the rotation of the wheel 63, so that the drive rod 61 can directly drive the wheel 63, the threaded valve stem 64 and the flow stop mechanism 5 to rise and fall synchronously.

[0059] Indirect drive mode: The outer side of valve pipe 4 is fixed with a protective sleeve 67 by welding angle steel bracket. The protective sleeve 67 is made of stainless steel and can resist rain, dust and fracturing fluid splashes in the field. The servo motor 68 is fixed inside the protective sleeve 67 by motor seat bolts. The output end of the servo motor 68 is fixed with the first gear 69 by a flat key. The first gear 69 meshes with the second gear 60 fixed to the outer side of the wheel 63 by welding, so as to realize the slow and precise rotation of the wheel 63.

[0060] When the formation pressure suddenly rises to 145 MPa during fracturing operations, exceeding the 140 MPa safety threshold, and the fracturing fluid needs to be shut off urgently: the control system sends an emergency shut-in signal, the first electric push rod 65 is energized and started, and the output end pushes the limit rod 66 to quickly insert into the limit hole of the wheel 63, rigidly locking the wheel 63 and the drive rod 61; the drive unit 7 is immediately started, and the output axial thrust drives the drive rod 61 to move rapidly downward along the limit slide rail 601, and the built-in sliding element 62 simultaneously drives the wheel 63, the threaded valve stem 64 and the flow-stopping mechanism 5 to descend rapidly along the axial direction; the flow-stopping mechanism 5 can then reach the flow-stopping position in the valve body 3, cut off the fracturing fluid channel, and complete the emergency shut-in.

[0061] When the fracturing fluid flow rate needs to be adjusted according to the permeability of the shale gas reservoir, such as reducing it from 55 cubic meters per hour to 35 cubic meters per hour: the control system sends a flow adjustment signal, the first electric push rod 65 starts in reverse, driving the limit rod 66 to retract upwards, releasing the rotation restriction on the wheel 63; the servo motor 68 starts at a preset speed, and through the meshing transmission of the first gear 69 and the second gear 60, drives the wheel 63 to rotate slowly; the trapezoidal internal thread of the wheel 63 cooperates with the trapezoidal external thread of the threaded valve stem 64, converting the rotational motion of the wheel 63 into the axial movement of the threaded valve stem 64, driving the flow-stopping mechanism 5 to rise and fall slowly; by adjusting the gap between the flow-stopping mechanism 5 and the internal channel of the valve body 3, the fracturing fluid flow rate can be finely adjusted, reducing the flow adjustment error. Example 2

[0062] like Figure 4 , Figure 5 , Figure 7 and Figure 8As shown, the sealing surface cooperates with the flow-stopping mechanism: the trapezoidal block 602 is reinforced and fixed in the center of the valve body 3 by welding and radial bolts. The material is wear-resistant steel with a hard alloy layer welded on the surface. The cross-section of the trapezoidal block 602 is an isosceles trapezoid, and the inner wall is a 25° inclined sealing surface to ensure a tight seal. The bottom of the connecting block 51 of the flow-stopping mechanism 5 is fixed to the valve 52 by welding. The valve 52 is a circular structure with a diameter matching the inner cavity of the valve body 3. A reducing rod 53 is fixed to the center of the valve 52 by spot welding. One end has a diameter of 20mm and the other end has a diameter of 15mm to enhance the bending strength. The thin end of the reducing rod 53 is fixed to the ball of the first universal joint seat 54 by threads. The outer shell of the first universal joint seat 54 is connected to the drain valve 55 by bolts. The material of the drain valve 55 matches that of the trapezoidal block 602, and the surface is also welded with hard alloy. The cooperation between the ball and the outer shell allows the angle of the drain valve 55 to be adjusted.

[0063] Multi-directional elastic support: Inside the valve 52, eight hollow columns 56, made of 20CrMnTi, are welded and fixed in a circular pattern. Each hollow column 56 has a sliding adaptation reset telescopic rod 57 with a chrome-plated surface for corrosion protection and friction reduction. The end of the reset telescopic rod 57 away from the hollow column 56 is fixed to the ball joint of the second universal joint seat 58 by threads. The outer shell of the second universal joint seat 58 is connected to the bleed valve 55 by bolts. The eight reset telescopic rods 57 form multi-directional elastic support for the bleed valve 55, ensuring that the bleed valve 55 is subjected to uniform force.

[0064] When the flow-stopping mechanism 5 descends to the flow-stopping position under the drive of the drive unit 7:

[0065] The wedge 50C first contacts the inclined sealing surface of the trapezoidal block 602. As the flow-stopping mechanism 5 continues to descend, the inclined sealing surface generates radial extrusion force, which converts the axial thrust of the drive unit 7 into sealing pressure. Under a high pressure of 140MPa, the sealing contact pressure can reach 210MPa, thus achieving initial sealing.

[0066] If the device has installation coaxiality error or slight deformation after long-term use, the ball joint-shell of the variable diameter rod 53 and the first universal joint seat 54, and the return telescopic rod 57 and the second universal joint seat 58 are matched to allow the vent valve 55 to automatically adjust its angle, ensuring that the sealing surface of the wedge block 50C and the trapezoidal block 602 are completely fitted without any local gaps; ultimately forming a double sealing structure of "sloping surface compression sealing + angle compensation". Example 3

[0067] like Figure 6 , Figure 7 , Figure 8 , Figure 9 , Figure 10 and Figure 11As shown, the buffer force transmission structure is as follows: the hollow column 56 is internally fitted with a push column 503 at the end away from the reset telescopic rod 57, and the push column 503 is fixed to a second fixing ring 506 by welding at the end away from the hollow column 56. It is a ring structure with a T-shaped groove on the inner side; the center plate 50B is internally fitted with a central plate 50B in the T-shaped groove of the second fixing ring 506, and can move radially. The wedge block 50C and the square block 50A are fixed to the outer side of the center plate 50B by welding, wherein there are 8 sets of square blocks 50A.

[0068] Elastic buffering and magnetic force cooperation: The outer side of the push column 503 has an annular second groove 504, and the sliding adapter 505 slides in the groove; the two ends of the sliding ring 505 are fixed to the outer rail 507 by bolts, which is divided into 8 groups, corresponding one to one with the square block 50A. The second magnetic block 509 is fixed inside the outer rail 507 by adhesive; the sliding adapter 500 slides inside the outer rail 507, and the first magnetic block 508 is fixed to the outside of the sliding block 508 by adhesive, and is opposite to the second magnetic block 509, generating a repulsive force. In the initial state, the repulsive force pushes the sliding block 500 to the outermost end of the outer rail 507 and into contact with the square block 50A.

[0069] Reset buffer fit: A radial groove 59 is opened inside the hollow column 56. A fixing ring 50 is fixed in the groove by welding to limit the maximum extension of the reset telescopic rod 57 and prevent the reset telescopic rod 57 from falling out. The sliding adapter 501 in the groove 59 has an L-shaped structure and is made of spring steel. One end of the folding rod 501 contacts the outside of the reset telescopic rod 57, and the other end is fixed with a reset spring 502 by welding. The end of the reset spring 502 away from the folding rod 501 is welded to the inner wall of the groove 59. In the initial state, the reset spring 502 is in a slightly compressed state, applying pre-pressure to the folding rod 501.

[0070] When wedge 50C and trapezoidal block 602 are pressed together, the pressure is transmitted and buffered through the following path: Wedge 50C, under pressure, drives the central disc 50B to move along the T-shaped groove of the second fixed ring 506 towards the valve 52; the square block 50A outside the central disc 50B simultaneously presses against the slide bar 500; the slide bar 500 overcomes the repulsive force between the first magnetic block 508 and the second magnetic block 509, moving inward towards the outer rail 507, transmitting the pressing force to the outer rail 507, and thus driving the slip ring 502... 05 moves outward along the second groove 504 of the push column 503; the slip ring 505 pushes the push column 503 to extend into the hollow column 56, the push column 503 squeezes the folding rod 501, causing the folding rod 501 to rotate around the contact point and compress the return spring 502; the return spring 502 generates an elastic reaction force, which is transmitted to the return telescopic rod 57 through the folding rod 501, and the eight return telescopic rods 57 simultaneously transmit the elastic support force to the vent 55, buffering the impact of high-pressure fracturing fluid on the sealing surface, reducing the impact force by 45%.

[0071] Conversely, the area of ​​the effluent valve 55 that experiences higher pressure, assuming it is the "high-pressure side," is first subjected to an additional axial thrust. This thrust overcomes the initial preload of the corresponding reset telescopic rod 57, causing the reset telescopic rod 57 on the high-pressure side to retract into the hollow column 56. At the same time, the reset telescopic rod 57 on the lower-pressure side is in the extended state, forming a support height difference on both sides of the effluent valve 55, which drives the effluent valve 55 to deflect towards the high-pressure side with the ball joint of the first universal joint seat 54 as the fulcrum.

[0072] The working principle of this invention is as follows: The wellhead body 1 serves as the supporting foundation, and fracturing fluid is transported to the valve body 3 through the tubing 2. The valve body 3 serves as the core control node, and the fracturing fluid is switched on and off by the raising and lowering of the flow-stopping mechanism 5. The drive unit 7 provides power, which is transmitted to the flow-stopping mechanism 5 through the control switching mechanism 6: the drive rod 61 drives the built-in sliding member 62 to move stably under the guidance of the limiting slide rail 601. The wheel 63 is threadedly engaged with the threaded valve stem 64. When the wheel 63 rotates, it drives the threaded valve stem 64 to move axially, thereby controlling the raising and lowering of the flow-stopping mechanism 5, adjusting the fracturing fluid flow rate or achieving flow stoppage.

[0073] The control mechanism 6 can switch between two drive modes to adapt to different operational needs:

[0074] Direct drive mode: The first electric push rod 65 pushes the limit rod 66 into the limit hole of the wheel 63, restricting the rotation of the wheel 63. The drive rod 61 directly drives the wheel 63, the threaded valve stem 64 and the flow stop mechanism 5 to rise and fall synchronously, realizing rapid opening and closing, which is suitable for emergency conditions.

[0075] Indirect drive mode: When the limit rod 66 retracts, the servo motor 68 drives the wheel 63 to rotate through the meshing of gear 69 and gear 60. The wheel 63 drives the threaded valve stem 64 to slowly rise and fall, thereby achieving high-precision flow regulation and meeting the needs of fine fracturing.

[0076] When the flow-stopping mechanism 5 descends to the flow-stopping position, the wedge block 50C fits against the inclined sealing surface of the trapezoidal block 602 inside the valve body 3, increasing the sealing pressure by utilizing the inclined surface compression effect to meet the liquid-stopping requirements of a 140MPa high-pressure environment. The cooperation between the reducing rod 53 and the first universal joint seat 54, and the reset telescopic rod 57 and the second universal joint seat 58, allows for small-angle adjustment of the vent valve 55, ensuring a tight fit with the sealing surface.

[0077] When the wedge block 50C and the trapezoidal block 602 are pressed together, the central disk 50B connected to the wedge block 50C will move along the second fixing ring 506 towards the valve 52. Immediately afterwards, the square block 50A fixedly connected to the outside of the central disk 50B will move outwards and press against the slide bar 500. The two ends of the slide bar 500 are slidably fitted inside the outer rail 507, and under the repulsive force of the first magnetic block 508 and the second magnetic block 509, it is located at the outermost end of the inner cavity of the outer rail 507. At this time, the pressing force on the slide bar 500 will be transmitted to the outer rail 507, and the outer side of the outer rail 507 is connected to the slide bar 502. The ring 505 is fixedly connected, so the slip ring 505 will move outward along the second groove 504 opened on the surface of the push column 503 until it pushes the push column 503 into the hollow column 56 and exerts a compressive force on the bending rod 501. The return spring 502 in the hollow column 56 applies elastic pressure to the return telescopic rod 57 through the bending rod 501 to buffer the impact when sealing and fitting. After the above force is transmitted, the return telescopic rods 57 in eight directions provide greater support to the vent 55, further weakening the high pressure impact, avoiding damage to the sealing structure due to hard contact, and ensuring the long-term stable operation of the device in a high-pressure environment.

[0078] The above embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made by those skilled in the art based on the above concepts without creative effort shall fall within the scope of protection of the present invention.

Claims

1. A 140 MPA gas recovery fracturing wellhead apparatus characterized by, include: The wellhead body serves as the basic load-bearing structure for high-pressure gas production fracturing operations. An oil pipe is connected to the outer end face of the wellhead body for transporting fracturing fluid. A valve body is installed at the end of the oil pipe away from the wellhead body to control the flow of fracturing fluid. The valve tube, flange, and drive unit are provided. The valve tube is located on the top of the valve body and communicates with the interior of the valve body. The flange is fixedly connected to the top of the valve tube by bolts and is used to seal the top of the valve tube. The drive unit is located on the top of the flange and provides driving force. A flow-stopping mechanism is provided inside the valve tube and can move axially along the valve tube to realize the delivery control and flow-stopping sealing of fracturing fluid in the valve body; A switching mechanism is provided inside the valve tube and above the flow-stopping mechanism. It is used to drive the flow-stopping mechanism to rise and fall and to switch the control mode. The switching mechanism includes a drive rod, which is fixedly installed at the center of the flange. The top end of the drive rod is connected to the output end of the drive unit via a coupling. An internal sliding member is fixedly connected to the outside of the drive rod. The outside of the internal sliding member is slidably adapted to a limited slide rail, which is fixedly connected to the inner wall of the valve pipe. The outer side of the built-in sliding member is connected to a wheel via a bearing, and the wheel can rotate relative to the built-in sliding member; A threaded valve stem is threadedly connected to the center of the wheel, the threaded valve stem extends along the axial direction of the wheel, and the bottom end of the threaded valve stem is fixedly connected to the flow-stopping mechanism. An electric push rod is fixedly installed inside the drive rod, and a limit rod is fixedly connected to the output end of the bottom of the electric push rod. The limiting rod is inserted into the preset limiting hole on the top of the wheel. When the limiting rod is inserted, it restricts the rotation of the wheel, so that the drive rod directly drives the wheel, the threaded valve stem and the flow stop mechanism to rise and fall synchronously. A protective sleeve is fixedly installed on the outside of the valve tube, and a servo motor is fixedly installed inside the protective sleeve. A first gear is fixedly connected to the outer side of the output end of the servo motor. A second gear meshes with the outer side of the first gear. The second gear is fixedly connected to the outer side of the wheel. The servo motor drives the wheel to rotate through gear transmission, thereby indirectly driving the threaded valve stem.

2. The 140MPA gas recovery fracturing wellhead device according to claim 1, characterized in that: A trapezoidal block is fixedly installed in the center of the valve body. The trapezoidal block has a trapezoidal cross-section and its inner wall is an inclined sealing surface. When the flow-stopping mechanism descends to the flow-stopping position, it comes into contact with the inclined sealing surface of the trapezoidal block. The pressure is increased by the pressure of the inclined surface, which improves the flow-stopping and sealing performance of the fracturing fluid.

3. The 140MPA gas recovery fracturing wellhead device according to claim 2, characterized in that: The flow-stopping mechanism includes a connecting block, the top of which is fixedly connected to the threaded valve stem, a valve is fixedly installed at the bottom of the connecting block, a reducing rod is fixedly installed at the center of the valve, a first universal joint seat is fixedly installed at the end of the reducing rod away from the valve, and a drain valve is fixedly connected at the end of the first universal joint seat away from the reducing rod. The variable diameter rod is fixedly connected to the ball joint inside the No. 1 universal joint seat.

4. The 140MPA gas recovery fracturing wellhead device according to claim 3, characterized in that: A hollow column is fixedly installed inside the valve. A reset telescopic rod is slidably adapted inside the hollow column. A second universal joint seat is fixedly installed at the end of the reset telescopic rod away from the hollow column. The end of the second universal joint seat away from the reset telescopic rod is fixedly connected to the vent valve. The reset telescopic rod is fixedly connected to the ball joint inside the No. 2 universal joint seat.

5. The 140MPA gas recovery fracturing wellhead device according to claim 4, characterized in that: The hollow column has a groove No. 1 inside, and a fixing ring No. 1 is fixedly installed inside the groove No.

1. The fixing ring No. 1 is used to limit the movement of the reset telescopic rod.

6. The 140MPA gas recovery fracturing wellhead device according to claim 5, characterized in that: The first groove is fitted with a sliding folding rod. The end of the folding rod away from the first groove is pressed against the outer side of the reset telescopic rod. A reset spring is fixedly connected to the outer side of the folding rod. The end of the reset spring away from the folding rod is fixedly connected to the inner wall of the first groove.

7. The 140MPA gas recovery fracturing wellhead apparatus of claim 6, wherein: The hollow column is internally fitted with a push column at the end away from the reset telescopic rod. A second fixing ring is fixedly connected to the end of the push column away from the hollow column. A central disk is slidably fitted to the inner side of the second fixing ring. A wedge is fixedly connected to the outer side of the central disk. The outer side of the wedge is squeezed and fitted with the trapezoidal block. A block is fixedly connected to the outer side of the central disk.

8. The 140MPa gas fracturing wellhead device according to claim 7, characterized in that: The push column has a second groove on its outer side. The second groove is fitted with a sliding ring. Both ends of the sliding ring are fixedly connected to an external rail. The external rail is fixedly installed with a second magnetic block. The external rail is fitted with a sliding strip. The outside of the sliding strip is fixedly connected to a first magnetic block. The first and second magnetic blocks have a repulsive relationship, and the outer side of the slider is squeezed and adapted to the block.

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