A gas production wellhead flow regulating device

Abstract

The present application relates to oil and gas exploitation technology field, specifically relates to a kind of gas production well wellhead flow regulating device, including tubing head and gas production tree, tubing head one end is used to connect in wellhead inner casing connection tubing head, the other end is connected to gas production tree, gas production tree includes four-way pipe and with four-way pipe one end sequentially communicated gate valve and needle valve, needle valve includes valve body, valve stem, packing pressing plate, elastic element, set elastic element make the thread on valve stem and the thread on one side of valve body always adhere, when valve stem and valve body relatively rotate, the adjusting air gap brought by thread gap can be eliminated, reduce adjustment error, improve the accuracy of flow control.Valve stem when just beginning to move and open plugging passage, resistance is minimum, and moving resistance gradually increases, can avoid that the regulation amplitude of valve stem is too large to cause flow out of control.And along with valve stem and open plugging passage, elastic element force storage increases, packing seal pressure rises in turn, improve the sealing reliability under high pressure working condition when plugging passage opens gas to pass.

Description

Technical Field

[0001] This invention relates to the field of oil and gas extraction technology, specifically to a wellhead flow regulation device for gas production wells. Background Technology

[0002] Natural gas wellhead equipment is a key piece of equipment in gas field development. One of its core functions is to precisely regulate the flow and pressure of high-pressure natural gas produced from the wellhead to meet the stable operation requirements of downstream gathering and transmission networks or processing facilities. In a typical wellhead production tree configuration, the needle valve, as a fine-tuning element, plays a crucial role in throttling and depressurizing the high-pressure gas flow and controlling its flow rate. The needle valve drives a conical sealing block to move through the threaded engagement between the valve stem and the valve body, changing the opening of the throttling channel and thus regulating the flow rate.

[0003] However, in practical engineering applications, existing needle valve structures still have some inherent problems that restrict flow control accuracy and long-term operational reliability. Firstly, traditional needle valves generally use a trapezoidal thread fit between the valve stem and body to achieve axial movement. However, after machining and assembly, the threaded pair inevitably has a certain axial clearance. This clearance leads to a "free-flow" phenomenon—the valve stem does not respond immediately after the operator turns the handwheel; the thread clearance must be eliminated before the sealing block can move. This free-flow adjustment makes it difficult for operators to accurately control the actual flow area, resulting in flow overshoot or undershoot, affecting the stability of downstream processes.

[0004] Secondly, needle valves typically employ a stuffing box sealing structure, achieving dynamic sealing by filling the space between the valve stem and body with flexible graphite or PTFE packing. To ensure sealing reliability under high-pressure conditions (such as when the valve is fully open), a large preload is often required on the packing. This results in a significant increase in frictional resistance during valve stem startup and rotation, leading to high operating torque and hindering fine-tuning.

[0005] In summary, when the high-pressure gas at the wellhead flows through the needle valve, even minor errors in the needle valve can cause significant fluctuations in the gas flow, affecting the adjustment accuracy and hindering safe production and stable gas supply on site. Summary of the Invention

[0006] This invention provides a wellhead flow rate regulating device for gas production wells to solve the problem of easy errors in the accuracy of existing gas production well flow rate regulation.

[0007] The gas wellhead flow rate regulating device of the present invention adopts the following technical solution: A wellhead flow regulation device for a gas production well includes a tubing head and a gas production tree. One end of the tubing head is connected to a casing head that connects to the inner casing of the wellhead, and the other end is connected to the gas production tree. The gas production tree includes a four-way pipe and a gate valve and a needle valve sequentially connected to one end of the four-way pipe. One end of the four-way pipe is used to connect to the tubing head, and the other two ends are used to connect to other components. The needle valve includes a valve body, a valve stem, a packing plate, and an elastic element. The valve stem is threaded to the valve body, and the axial direction of the valve stem is defined as the front-rear direction. A conical sealing block is coaxially arranged on the valve stem, and the smaller end of the block is defined as the front side. A conical sealing block is arranged inside the valve body. The valve body is sealed by a sealing block that abuts against the sealing channel. The sealing block moves backward to open the sealing channel. The valve body is filled with packing material, which is located in front of the sealing block and in front of the packing pressure plate. The valve stem passes through the packing pressure plate and the packing. An elastic element is located between the valve stem and the packing pressure plate and is in a stored state, which pushes the valve stem so that the thread on the valve stem always fits one side of the thread on the valve body. When the valve stem moves backward to open the sealing channel, the valve stem further squeezes the packing pressure plate backward through the elastic element, thereby increasing the sealing effect of the packing on the valve stem and valve body.

[0008] Optionally, a fluid channel perpendicular to the valve stem axis is provided in the valve body, and two sealing plates are provided in the fluid channel. The two sealing plates are located on both sides of the valve stem and define a conical sealing channel between the two sealing plates. Each sealing plate has a through hole, and the two through holes are located on the front and rear sides of the sealing channel, respectively.

[0009] Optionally, a guide cylinder is also provided in the valve body. The guide cylinder is coaxial with the valve stem, and the rear end of the valve stem slides in conjunction with the guide cylinder.

[0010] Optionally, the needle valve also includes a rotary handwheel, which is detachably fixed to the valve stem.

[0011] Optionally, a sealing sleeve is also connected to the handwheel. The sealing sleeve is slidably fitted onto the valve body to block the part of the valve stem located outside the valve body.

[0012] Optionally, the valve body has a split structure, including a threaded part, a middle part, and an end cap part that are detachably connected from front to back along the valve stem axis. The middle part has the fluid passage and the sealing passage, and the packing is located in the middle part. The threaded part is used to engage with the valve stem thread, and the end cap part is used to seal the rear end of the valve body.

[0013] Optionally, the valve stem is provided with a threaded section with a diameter larger than that of the valve stem body, and the threaded section is used to engage with the threaded part.

[0014] Optionally, the sealing plate is curved.

[0015] Optionally, one end of the four-way pipe is connected to the oil pipe head through the main pipe, and a main valve is installed on the main pipe; the other two ends of the four-way pipe are respectively connected to a second pressure gauge and a dewaxing assembly, and a shut-off valve is respectively installed between the four-way pipe and the second pressure gauge and the dewaxing assembly.

[0016] Optionally, a first pressure gauge and an auxiliary channel are respectively provided on both sides of the oil pipe head, and a shut-off valve is provided between the first pressure gauge and the auxiliary channel.

[0017] The beneficial effects of the present invention are: the gas wellhead flow regulating device of the present invention is equipped with an elastic element so that the thread on the valve stem and one side of the thread on the valve body are always in contact. When the valve stem and the valve body rotate relative to each other, the adjustment space caused by the thread clearance can be eliminated, the adjustment error can be reduced, and the accuracy of flow control can be improved.

[0018] When the valve stem first starts to rotate and open the sealing channel, the stored force of the elastic element is at its minimum. When the valve stem first starts to move and open the sealing channel, the resistance is at its minimum, making it easier to open. Furthermore, the gradually increasing resistance can prevent the valve stem from adjusting too much and causing the flow to become uncontrollable.

[0019] Furthermore, when the sealing block on the valve stem is blocking the passage, the elastic element's stored force is at its minimum, and the sealing pressure of the packing on the valve stem and valve body is also at its lowest level, facilitating fine-tuning and reducing resistance when the valve stem starts to rotate. As the valve stem moves to open the blocking passage, the elastic element's stored force increases, and the packing sealing pressure rises accordingly, reducing the impact of valve stem movement on the packing's sealing performance and improving sealing reliability under high-pressure conditions when the blocking passage is open and gas passes through. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the overall structure of an embodiment of the gas wellhead flow regulation device of the present invention; Figure 2 This is a front view of the overall structure of an embodiment of the gas wellhead flow regulation device of the present invention; Figure 3 This is a schematic diagram of the needle valve structure in an embodiment of the gas wellhead flow regulation device of the present invention; Figure 4 This is a cross-sectional schematic diagram of the needle valve in an embodiment of the gas wellhead flow regulation device of the present invention; Figure 5 for Figure 4 Enlarged view of point B in the middle; Figure 6 for Figure 4 Enlarged view of point C in the middle; Figure 7 for Figure 4 Enlarged view of point D in the middle; Figure 8 This is a cross-sectional schematic diagram of the needle valve being opened in an embodiment of the gas wellhead flow regulation device of the present invention.

[0022] In the diagram: 100, oil pipe head; 110, first pressure gauge; 120, auxiliary channel; 300, gas source tree; 310, four-way pipe; 320, gate valve; 330, needle valve; 331, valve body; 3311, sealing plate; 3312, through hole; 332, valve stem; 333, packing pressure plate; 334, elastic element; 335, packing; 336, guide cylinder; 337, sealing sleeve; 338, handwheel; 340, main valve; 350, second pressure gauge; 360, dewaxing assembly. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] An embodiment of the wellhead flow regulation device for gas production wells according to the present invention, such as... Figures 1 to 8As shown, the system includes a tubing head 100 and a gas production tree 300. One end of the tubing head 100 is connected to the casing head inside the wellhead, and the other end is connected to the gas production tree 300. The gas production tree 300 includes a four-way pipe 310 and a gate valve 320 and a needle valve 330 connected in sequence to one end of the four-way pipe 310. One end of the four-way pipe 310 is used to connect to the tubing head 100, and the other two ends are used to connect to other components. Specifically, the casing head connects to the multiple layers of casing run into the well, and is used to support the casing and separate the multiple layers of casing. The tubing head 100 serves as a connection and transition between the casing head and the gas production tree 300, preventing oil and gas from entering the wellhead or leaking to the surface. A first pressure gauge 110 and an auxiliary channel 120 are respectively installed on both sides of the tubing head 100, with shut-off valves between them. The first pressure gauge 110 monitors the gas pressure inside the tubing head 100, while the auxiliary channel 120 is used for safe downhole operations such as casing gas release, water injection, and well flushing, meeting production and maintenance needs. The gas production tree 300 is the core wellhead device located at the very top of the gas well. It mainly uses a series of valves for multi-stage throttling and pressure reduction, precisely controlling the high pressure at the wellhead to the required stable downstream pressure. The gate valve 320's main task is to safely cut off or allow gas flow, enabling rapid and complete shutdown of the gas source in emergencies to ensure safety. The needle valve 330 acts as a flow regulating valve, used to throttle high-pressure gas and precisely control the gas flow and pressure.

[0025] The structures of the casing head, tubing head 100, and gate valve 320 are all existing technologies, and their specific structures will not be described in detail.

[0026] The needle valve 330 includes a valve body 331, a valve stem 332, a packing plate 333, and an elastic element 334. The valve stem 332 is threadedly engaged with the valve body 331. The axial direction of the valve stem 332 is defined as the front-rear direction. A conical sealing block is coaxially arranged on the valve stem 332, and its small end is defined as the front side. A conical sealing channel is provided inside the valve body 331. The sealing block abuts against the wall of the sealing channel to seal the valve body 331, and the sealing block moves backward to open the sealing channel. The valve body 331 is filled with packing 335, which is located in front of the sealing block. The packing plate 333 is located in front of the packing 335, and the valve stem 332 passes through the packing plate 333 and the packing 335. The elastic element 334 is located between the valve stem 332 and the packing plate 333 and is in a stored state, thereby pushing the valve stem 332 so that the thread on the valve stem 332 is always in contact with one side of the thread on the valve body 331; and when the valve stem 332 moves backward to open the sealing channel, the valve stem 332 further squeezes the packing plate 333 backward through the elastic element 334, thereby increasing the sealing effect of the packing 335 on the valve stem 332 and the valve body 331.

[0027] The elastic element 334 ensures that one side of the thread on the valve stem 332 is always in contact with the thread on the valve body 331. This eliminates the adjustment backlash caused by thread clearance when the valve stem 332 and valve body 331 rotate relative to each other, reducing adjustment errors and improving the accuracy of flow control. Furthermore, when the valve stem 332 first begins to rotate and open the sealing passage, the elastic element 334 has its minimum stored force. As the valve stem 332 moves backward, the sealing passage is opened to a greater extent, the stored force of the elastic element 334 increases, and the frictional force of the threaded engagement between the valve stem 332 and valve body 331 increases. This gradually increases the resistance to movement of the valve stem 332. Therefore, the resistance is minimal when the valve stem 332 first begins to move and open the sealing passage, making opening easier. The gradually increasing resistance also prevents excessive adjustment of the valve stem 332, which could lead to flow control failure. Furthermore, when the sealing block on the valve stem 332 is blocking the channel, the stored force of the elastic element 334 is at its minimum, and the sealing pressure of the packing 335 on the valve stem 332 and valve body 331 is also at its minimum level, which facilitates fine adjustment and reduces the resistance when the valve stem 332 starts to rotate. As the valve stem 332 moves to open the blocking channel, the stored force of the elastic element 334 increases, and the sealing pressure of the packing 335 increases accordingly, reducing the impact of the movement of the valve stem 332 on the sealing performance of the packing 335 and improving the sealing reliability under high pressure conditions when the blocking channel is open and gas passes through.

[0028] In this embodiment, a fluid channel perpendicular to the axial direction of the valve stem 332 is provided within the valve body 331. One end of the fluid channel is connected to the upstream gate valve 320, and the other end is connected to the downstream pipeline. Two sealing plates 3311 are provided within the fluid channel, located on both sides of the valve stem 332, defining a conical sealing channel between them. Each sealing plate 3311 has a through hole 3312, located on the front and rear sides of the sealing channel. When the sealing block on the valve stem 332 abuts against the two sealing plates 3311, the sealing channel closes, the two through holes 3312 are separated, and the fluid channel is closed. Since the two through holes 3312 are located on the front and rear sides of the sealing channel, when the sealing block moves to open the sealing channel, the gas reverses direction at the sealing channel, reducing the impact of the gas on the valve stem 332.

[0029] In this embodiment, a guide cylinder 336 is also provided inside the valve body 331. The guide cylinder 336 is coaxial with the valve stem 332, and the rear end of the valve stem 332 is slidably engaged with the guide cylinder 336. The guide cylinder 336 guides the movement of the valve stem 332 and reduces the swaying of the valve stem 332 under gas impact, thereby increasing its movement stability.

[0030] In this embodiment, the needle valve 330 also includes a handwheel 338, which is detachably and fixedly connected to the valve stem 332. A sealing sleeve 337 is also connected to the handwheel 338, which is slidably sleeved on the outside of the valve body 331 to block the portion of the valve stem 332 located outside the valve body 331.

[0031] In this embodiment, the valve body 331 is a split structure, including a threaded portion, a middle portion, and an end cap portion that are detachably connected sequentially from front to back along the axial direction of the valve stem 332. The middle portion has the fluid passage and the sealing passage, and the packing 335 is located in the middle portion. The threaded portion is used to thread into the valve stem 332, and the end cap portion is used to seal the rear end of the valve body 331. The guide cylinder 336 is fixed to the end cap portion of the valve body 331.

[0032] In this embodiment, the valve stem 332 is provided with a threaded section whose diameter is larger than that of the valve stem 332 body. The threaded section is used to engage with the threaded part. The elastic element 334 is a spring, which is sleeved on the valve stem 332, and its two ends abut against the threaded section and the packing pressure plate 333, respectively.

[0033] In this embodiment, the sealing plate 3311 is arc-shaped to guide the smooth flow of gas.

[0034] In this embodiment, one end of the four-way pipe 310 is connected to the oil pipe head 100 via a main pipe, and a main valve 340 is installed on the main pipe; the other two ends of the four-way pipe 310 are respectively connected to a second pressure gauge 350 and a dewaxing assembly 360, and shut-off valves are respectively provided between the second pressure gauge 350 and the dewaxing assembly 360. The first pressure gauge 110 and the second pressure gauge 350 are both existing technologies used to monitor the gas pressure inside the pipeline. The dewaxing assembly 360 is located at the top of the four-way pipe 310 and can be fitted with a special dewaxing blade for mechanical dewaxing; its specific structure is existing technology and will not be described in detail here.

[0035] In use, the wellhead flow regulating device of this invention allows gas in the well to flow upward along the casing, sequentially passing through the casing head, tubing head 100, the four-way pipe 310 of the gas tree 300, gate valve 320, and needle valve 330 before flowing downstream. The gas flow rate is regulated by the needle valve 330 to ensure a stable gas flow rate and meet downstream delivery requirements. Specifically, rotating the handwheel 338 drives the valve stem 332 to rotate. The valve stem 332, in its threaded engagement with the valve body 331, rotates and moves backward, disengaging from the sealing plate 3311, thereby opening the sealing channel. The greater the backward movement of the valve stem 332, the greater the degree of opening of the sealing channel, and the greater the gas flow rate that can pass through. During the rotation and movement of the valve stem 332, the elastic element 334 ensures that the front side of the thread on the valve stem 332 remains in contact with the thread on the valve body 331. When the valve stem 332 rotates relative to the valve body 331, the adjustment clearance caused by the thread gap is eliminated, reducing adjustment errors and improving the accuracy of flow control. The greater the rearward movement of the valve stem 332, the greater the compression of the packing 335 by the packing pressure plate 333 through the elastic element 334, and the higher the sealing pressure. This ensures a proper seal between the valve stem 332 and the valve body 331 when the sealing passage is open. When it is necessary to close the needle valve 330, the handwheel 338 is turned in the opposite direction, causing the valve stem 332 to move and rotate until it abuts against the sealing plate 3311, closing the sealing passage and stopping the gas flow.

[0036] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A wellhead flow rate regulating device for gas production wells, characterized in that, It includes a tubing head and a gas production tree. One end of the tubing head is used to connect to the casing head connected to the wellhead casing, and the other end is connected to the gas production tree. The gas production tree includes a four-way pipe and a gate valve and a needle valve connected in sequence to one end of the four-way pipe. One end of the four-way pipe is used to connect to the tubing head, and the other two ends are used to connect to other components. The needle valve includes a valve body, valve stem, packing plate, and elastic element. The valve stem is threaded to the valve body, and the axial direction of the valve stem is defined as the front-to-back direction. A conical sealing block is coaxially mounted on the valve stem, with its smaller end defined as the front side. A conical sealing channel is provided inside the valve body. The sealing block abuts against the sealing channel to seal the valve body, and the sealing block moves backward to open the sealing channel. The valve body is filled with packing material, which is located in front of the sealing block. The packing plate is located in front of the packing material, and the valve stem passes through the packing plate and the packing material. The elastic element is located between the valve stem and the packing plate and is in a stored state, which pushes the valve stem so that the thread on the valve stem always fits against one side of the thread on the valve body. When the valve stem moves backward to open the sealing channel, the valve stem further squeezes the packing plate backward through the elastic element, thereby increasing the sealing effect of the packing on the valve stem and valve body. The valve body has a fluid channel perpendicular to the valve stem axis. Two sealing plates are installed in the fluid channel. The two sealing plates are located on both sides of the valve stem and define a conical sealing channel between the two sealing plates. Each sealing plate has a through hole, and the two through holes are located on the front and rear sides of the sealing channel, respectively. The valve body is also equipped with a guide cylinder, which is coaxial with the valve stem, and the rear end of the valve stem slides in conjunction with the guide cylinder. The valve body has a split structure, including a threaded part, a middle part, and an end cap part that are detachably connected from front to back along the valve stem axis. The middle part has the fluid passage and the sealing passage, and the packing is located in the middle part. The threaded part is used to engage with the valve stem thread, and the end cap part is used to seal the rear end of the valve body.

2. The wellhead flow rate regulating device for gas production wells according to claim 1, characterized in that, The needle valve also includes a rotary handwheel, which is detachably fixed to the valve stem.

3. The wellhead flow rate regulating device for gas production wells according to claim 2, characterized in that, A sealing sleeve is also connected to the handwheel. The sealing sleeve is slidably fitted onto the valve body to block the part of the valve stem located outside the valve body.

4. The wellhead flow rate regulating device for gas production wells according to claim 1, characterized in that, The valve stem has a threaded section with a diameter larger than that of the valve stem body. The threaded section is used to engage with the threaded part.

5. The wellhead flow rate regulating device for gas production wells according to claim 1, characterized in that, The sealing plate is curved.

6. The wellhead flow rate regulating device for gas production wells according to claim 1, characterized in that, One end of the four-way pipe is connected to the oil pipe head through the main pipe, and a main valve is installed on the main pipe; the other two ends of the four-way pipe are respectively connected to the second pressure gauge and the dewaxing assembly, and a shut-off valve is installed between the two pressure gauges and the dewaxing assembly.

7. The wellhead flow rate regulating device for gas production wells according to claim 1, characterized in that, A first pressure gauge and an auxiliary channel are respectively installed on both sides of the oil pipe head, and a shut-off valve is installed between the first pressure gauge and the auxiliary channel.

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