Electric valve for gas production wellhead and method of use

Abstract

This invention relates to the field of gas wellhead control technology, specifically an electric valve for gas production wellheads and its usage method. The former includes a valve body, valve stem, drive assembly, and sealing core assembly, with a valve cavity within the valve body. This invention features a reasonable and compact structure. By setting a primary valve seat and a secondary valve seat, the electric valve for gas production wellheads can achieve different adjustment functions at different stages during the adjustment process. During well opening and closing, it can achieve precise control of the wellhead flow rate, preventing the valve and pipeline from freezing due to reduced flow caused by excessive valve opening. Furthermore, it can adjust the opening of the electric valve for gas production wellheads based on downstream pressure or flow rate during production, making adjustment more convenient. During intermittent production of the gas well, when the gas well's production capacity and liquid carrying capacity are low, the drive assembly can periodically move the valve stem downwards to close the valve, thereby achieving intermittent production and improving the gas well's productivity.

Description

Technical Field

[0001] This invention relates to the field of gas wellhead control technology, specifically an electric valve for gas production wellheads and its usage method. Background Technology

[0002] The entire life cycle of a gas well mainly includes five stages: the initial production stage, the natural continuous production stage, the supplementary continuous production stage, the intermittent production stage, and the economically inefficient stage. In the later stages of gas well production, the well's capacity gradually declines, and its own energy cannot meet the production demand for drainage. At this point, intermittent drainage comes into play. Intermittent drainage can meet the drainage needs of most low-production wells and is currently an important drainage method in the gas well production process. Meanwhile, the shutdown and maintenance of gas gathering stations and natural gas processing plants will close a large number of gas wells, resulting in a very heavy workload for well opening and closing operations after maintenance. Because well opening and closing operations require on-site operation at each wellhead, there is a shortage of actual on-site personnel, especially when opening a large number of gas wells. Firstly, there is a relative lack of personnel and significant financial resources are consumed; secondly, the well opening time is relatively long, which to some extent cannot meet production needs.

[0003] A gas wellhead is a device installed at the wellhead in oil and gas drilling to suspend casing and tubing, and to seal the annular space between the tubing and casing, as well as between each layer of casing. Valves are control components in fluid transport systems, with functions such as shut-off, regulation, diversion, backflow prevention, pressure stabilization, diversion, or overflow pressure relief. A sealing valve, also called an airtight valve, is an auxiliary device that can divide a ventilation system into several zones. It has good airtightness and can meet the zero leakage requirements in special situations.

[0004] Chinese patent document CN216894332U discloses a self-sealing fracturing gas wellhead valve, which includes a valve body, a handwheel, a valve stem, and a valve plate. A positioning block is located below the handwheel, with recessed holes on both sides of the outer wall of the positioning block. A housing is installed on both sides of the positioning block, with a slotted hole in the center of the upper surface of each housing. A connecting rod is movably mounted inside the slotted hole, and a connecting plate is welded to the top of the connecting rod. Pins are symmetrically inserted into the edge of the connecting plate, penetrating through it. Protrusions are symmetrically fixed to the edge of the upper surface of the housing, with pin holes on their surfaces. A protruding post is movably mounted at the end of the housing. Guide rods are symmetrically welded to the inner side of the housing, and a rigid spring is sleeved on the outer wall of the guide rod. A slider is movably mounted on one side of the rigid spring.

[0005] In the existing technology, electric valves are mainly composed of electric actuators and valve bodies. The installation of electric actuators and valve bodies at the wellhead is relatively troublesome and requires a long time to assemble. Moreover, the flow rate of the medium cannot be accurately controlled during the well opening and closing process. Production pipelines under the original production mode are prone to freezing and blockage. During the intermittent production period of the gas well, it is not possible to shut down the well in time to achieve intermittent production. Summary of the Invention

[0006] This invention provides an electric valve for gas wellheads and its usage method, which overcomes the shortcomings of the prior art and can effectively solve the problem that the opening time of existing large-scale gas well opening operations is relatively long and cannot meet production needs to a certain extent.

[0007] One of the technical solutions of this invention is achieved through the following measures: a gas wellhead electric valve, comprising a valve body, a valve stem, a drive assembly, and a sealing core assembly. The valve body has a valve cavity, and the outer side of the valve body has an inlet and an outlet. The other ends of both the inlet and outlet are connected to the valve cavity. A secondary valve seat is provided in the valve cavity corresponding to the position between the inlet and outlet. A sealing core assembly is provided on the upper side of the secondary valve seat. The sealing core assembly includes a primary valve seat, an elastic reset element, and a connecting pin. A primary valve seat with its upper end located above the secondary valve seat is provided on the upper inner side of the secondary valve seat. The upper end of the primary valve seat has a flow passage with its lower end connected to the outlet. A flow passage connecting the valve body to the valve cavity is provided on the upper side of the valve body corresponding to the position of the primary valve seat. The control channel is connected, and a valve stem capable of moving up and down is sealed and installed within the control channel. An elastic reset component is installed between the lower outer side of the valve stem and the first-stage valve seat. Several strip-shaped guide holes with internal and external communication are evenly distributed circumferentially on the upper outer side of the first-stage valve seat. A connecting pin with its end fixed to the outer side of the valve stem is slidably installed in each guide hole. A valve core is fixed at the lower end of the valve stem corresponding to the position below the connecting pin. When the valve core moves downward, it can close the flow passage. When the valve core moves upward, it can open the flow passage or create a gap between the lower end of the first-stage valve seat and the upper end of the second-stage valve seat. A drive assembly that enables the valve stem to move up and down is provided on the upper side of the valve body.

[0008] The following are further optimizations and / or improvements to one of the above-mentioned inventive technical solutions: A valve cover can be fixedly installed in the aforementioned control through hole. A sealing packing is provided between the outer side of the middle part of the valve stem and the inner side of the valve cover. The drive assembly is fixedly installed on the upper side of the valve cover.

[0009] An outer ring platform can be fixed on the lower outer side of the first-stage valve seat below the corresponding guide hole. The lower center of the valve cover has a downward-facing mounting groove. A support plate fitted on the outside of the valve stem is fixedly installed in the mounting groove. An elastic reset member is installed between the upper end of the outer ring platform and the lower end of the support plate.

[0010] The aforementioned drive assembly may include an electric actuator and a connecting component. The connecting component includes a mounting plate and a positioning mechanism. The mounting plate is located above the valve cover, and a number of positioning mechanisms are spaced circumferentially along the lower side of the mounting plate. The lower side of each positioning mechanism is fixedly mounted to the upper side of the valve cover. The electric actuator is fixedly mounted on the upper side of the mounting plate, and the output shaft of the electric actuator is connected to the upper end of the valve stem via a transmission connection.

[0011] The aforementioned positioning mechanism may include a screw, a mounting sleeve, a positioning head, a positioning sleeve, and a threaded sleeve. At least two vertically penetrating lower mounting holes are spaced circumferentially on the upper side of the valve cover. A threaded sleeve is fixedly installed in each lower mounting hole. An upper mounting hole is provided on the upper side of the mounting plate corresponding to each lower mounting hole. A screw, with its lower outer side screwed into the threaded sleeve at the corresponding position, is provided in each upper mounting hole. A mounting sleeve is fitted on the outer side of each screw. The upper part of each mounting sleeve is fitted into the upper mounting hole at the corresponding position. A positioning head is fixedly installed on the lower outer side of each mounting sleeve. A positioning sleeve, with its lower end fixedly installed to the upper side of the valve cover, is fitted on the outer side of each positioning head. A radially penetrating insertion hole is provided on the outer side of the positioning head corresponding to each insertion hole. A slot is provided on the outer side of each insertion hole. A pin, with its end inserted into the insertion hole at the corresponding position, is provided in each insertion hole.

[0012] Limiting rings can be fixedly installed on the outer side of the mounting sleeves at the upper and lower positions of the mounting plate, and a knob is fixedly installed on the upper end of the screw at the upper position of the mounting plate.

[0013] The upper outer side of the aforementioned secondary valve seat can be screwed into the valve cavity. A limiting step is provided in the valve cavity corresponding to the position below the secondary valve seat, and a sealing gasket is installed between the limiting step and the lower side of the secondary valve seat.

[0014] The second technical solution of the present invention is achieved through the following measures: a method for using an electric valve at the gas wellhead, comprising the following steps: S1, after removing the needle valve from the oil wellhead, install the electric valve at the gas wellhead; S2, when the production well is in intermittent production, the valve stem is moved downward by the electric actuator, so that the valve core closes the first-stage valve seat, and the first-stage valve seat closes the second-stage valve seat, that is, the electric valve at the gas wellhead is in the closed state. S3, the pressure inside the production tree begins to build up. The pressure data inside the production tree is monitored. When the oil pressure inside the production tree reaches the set value, the valve stem moves upward through the electric actuator, the first-stage valve seat opens the second-stage valve seat, and the production well begins this round of production. S4, set the opening of the first-stage valve seat to the first set value and the second set value in sequence, and set the opening of the second-stage valve seat to the third set value and the fourth set value in sequence; S5, the electric actuator starts working and drives the valve stem to move upward. After the valve stem moves upward, the opening of the first-stage valve seat gradually becomes the first set value, and the opening of the valve body remains unchanged after reaching the first set value. S6, after the first set time is continuously opened, the electric actuator causes the valve stem to continue to move upward. After the valve stem moves upward, the opening of the first-stage valve seat gradually changes from the first set value to the second set value. The opening of the valve body remains unchanged after the second set value is reached. S7, after the second set time is continuously opened, the electric actuator causes the valve stem to continue to move upward. After the valve stem moves upward, it drives the first-stage valve seat to move upward, causing the opening of the second-stage valve seat to gradually change to the third set value. The opening of the valve body remains unchanged after reaching the third set value. S7, after the third set time is continuously opened, the electric actuator causes the valve stem to continue to move upward. After the valve stem moves upward, it drives the first-stage valve seat to move upward, so that the opening of the second-stage valve seat gradually changes from the third set value to the fourth set value and then continues production. S8 monitors the pressure before the valve body. If the pressure before the valve body is less than the production set value, the electric actuator will activate and cause the valve stem to move downward. After the valve stem moves downward, the valve body will be closed until the valve body is completely closed, and the current production cycle will end.

[0015] The following are further optimizations and / or improvements to the second technical solution of the above invention: Step S5 specifically involves the electric actuator starting to work and driving the valve stem to move upward. After the valve stem moves upward, the opening of the first-stage valve seat gradually changes to the first set value. The pressure downstream of the valve body is monitored. If the pressure downstream of the valve body is greater than the set value, the output shaft of the electric actuator rotates in the opposite direction, causing the valve stem to move downward quickly and close the valve body. If the pressure downstream of the valve body is less than or equal to the set value, the opening of the valve body remains unchanged after reaching the first set value.

[0016] This invention features a reasonable and compact structure. By setting a primary valve seat and a secondary valve seat, the gas wellhead electric valve can achieve different adjustment functions at different stages during the adjustment process. During well opening and closing, it can achieve precise control of the wellhead flow rate, avoiding the phenomenon of valve and pipeline freezing due to reduced flow rate caused by excessive valve opening. It can also adjust the opening of the gas wellhead electric valve according to the downstream pressure or flow rate during the production process, making adjustment more convenient. During the intermittent production of the gas well, when the gas well production capacity and liquid carrying capacity are low, the valve stem can be periodically moved downward and the valve can be closed by the drive assembly, or the valve stem can be moved downward and the valve can be closed when the well pressure is lower than the set value, thereby achieving intermittent production and improving the gas well's productivity. Attached Figure Description

[0017] Appendix Figure 1 These are schematic diagrams of the main structure of embodiments one to seven of the present invention.

[0018] Appendix Figure 2 This is a schematic diagram of the main cross-sectional structure of the valve body in Embodiments 1 to 7 of the present invention.

[0019] Appendix Figure 3 This is a schematic diagram of the main cross-sectional structure of the first-stage valve seat when it is open in embodiments one to seven of the present invention.

[0020] Appendix Figure 4 This is a schematic diagram of the main cross-sectional structure of the secondary valve seat when it is open in embodiments one to seven of the present invention.

[0021] Appendix Figure 5 For the appendix Figure 4 A magnified structural diagram of point A in the middle.

[0022] Appendix Figure 6 This is a schematic diagram of the main cross-sectional structure of the connecting components in embodiments four to seven of the present invention.

[0023] Appendix Figure 7 This is a schematic diagram of the main structure of the positioning mechanism in embodiments five to seven of the present invention.

[0024] Appendix Figure 8 This is a schematic diagram of the main structure of Embodiment 8 of the present invention.

[0025] The codes in the attached diagram are as follows: 1 for valve body, 2 for valve cavity, 3 for inlet, 4 for outlet, 5 for secondary valve seat, 6 for primary valve seat, 7 for elastic reset element, 8 for flow passage, 9 for valve stem, 10 for guide hole, 11 for connecting pin, 12 for valve core, 13 for valve cover, 14 for sealing packing, 15 for outer ring platform, 16 for support plate, 17 for electric actuator, 18 for mounting plate, 19 for screw, 20 for mounting sleeve, 21 for positioning head, 22 for positioning sleeve, 23 for threaded sleeve, 24 for insertion hole, 25 for pin, 26 for limit ring, 27 for knob, 28 for sealing gasket, 29 for Christmas tree, and 30 for emergency shut-off valve. Detailed Implementation

[0026] The present invention is not limited to the following embodiments, and specific implementation methods can be determined according to the technical solutions and actual conditions of the present invention.

[0027] In this invention, for ease of description, the description of the relative positions of the components is based on the appendix to the specification. Figure 1 The layout is described using a diagrammatic method, such as the positional relationships of front, back, top, bottom, left, and right, which are based on the instructions attached. Figure 1 The orientation of the layout is determined by the direction of the map.

[0028] The present invention will be further described below with reference to embodiments and accompanying drawings: Example 1: As shown in the attached document Figures 1 to 4As shown, the gas wellhead electric valve includes a valve body 1, a valve stem 9, a drive assembly, and a sealing core assembly. The valve body 1 has a valve cavity 2, and an inlet 3 and an outlet 4 on its outer side. The other ends of both the inlet 3 and outlet 4 are connected to the valve cavity 2. A secondary valve seat 5 is located within the valve cavity 2 between the inlet 3 and outlet 4. A sealing core assembly is located on the upper side of the secondary valve seat 5. The sealing core assembly includes a primary valve seat 6, an elastic reset element 7, and a connecting pin 11. A primary valve seat 6, with its upper end positioned above the secondary valve seat 5, is located on the inner side of the upper part of the secondary valve seat 5. A flow passage 8, with its lower end connected to the outlet 4, is located at the upper end of the primary valve seat 6. A control channel, connected to the valve cavity 2, is located on the upper side of the valve body 1 corresponding to the position of the primary valve seat 6. A valve stem 9 capable of moving up and down is sealed and installed inside the channel. An elastic reset member 7 is installed between the lower outer side of the valve stem 9 and the first-stage valve seat 6. Several strip-shaped guide holes 10 with internal and external communication are evenly distributed circumferentially on the upper outer side of the first-stage valve seat 6. A connecting pin 11 with its end fixed to the outer side of the valve stem 9 is slidably installed in each guide hole 10. A valve core 12 is fixed at the lower end of the valve stem 9 corresponding to the position below the connecting pin 11. When the valve core 12 moves downward, it can close the flow passage 8. When the valve core 12 moves upward, it can open the flow passage 8 or create a gap between the lower end of the first-stage valve seat 6 and the upper end of the second-stage valve seat 5. A drive assembly that enables the valve stem 9 to move up and down is provided on the upper side of the valve body 1.

[0029] According to the requirements, the elastic reset element 7 is a known existing technology, such as a compression spring. When a smaller opening is required, the valve stem 9 moves upward, and the connecting pin 11 moves from the lower end to the upper end of the guide hole 10, so that the annular area between the valve core 12 and the inner side of the first-stage valve seat 6 gradually increases. This process can meet the smaller opening requirement of the gas wellhead electric valve. When a larger opening is required, the valve stem 9 continues to move upward, and the connecting pin 11 drives the first-stage valve seat 6 to move upward under the action of the valve stem 9. After the first-stage valve seat 6 moves upward, the upper end of the first-stage valve seat 6 compresses the elastic reset element 7, so that the elastic reset element 7 stores energy. At the same time, the lower end of the first-stage valve seat 6 gradually separates from the inner side of the second-stage valve seat 5. This process can meet the larger opening requirement of the gas wellhead electric valve.

[0030] During use, by setting a primary valve seat 6 and a secondary valve seat 5, the gas wellhead electric valve can achieve different adjustment functions at different stages of the adjustment process. During well opening and closing, it can achieve precise control of the wellhead flow rate, avoiding the phenomenon of valve and pipeline freezing due to reduced flow rate when the valve opening is too large. It can also adjust the opening of the gas wellhead electric valve according to the downstream pressure or flow rate during the production process, making adjustment more convenient. During the intermittent production of the gas well, when the gas well production capacity and liquid carrying capacity are low, the valve stem 9 can be periodically moved downward and the valve can be closed by the drive assembly, or the valve stem 9 can be moved downward and the valve can be closed when the well pressure is less than the set value, thereby achieving intermittent production and improving the gas well's production capacity.

[0031] By adopting a dual-seat structure with a primary valve seat 6 and a secondary valve seat 5, the size of the valve core 12 and the valve seat can be reduced, thus providing excellent regulation during valve opening. Through the control of the drive assembly, the problems of excessive pressure after the valve and freezing blockage of the pipeline after the valve can be effectively solved. After the flow rate stabilizes, the primary valve seat 6 becomes the secondary valve core (the valve core 12 at the lower end of the valve stem 9 is the primary valve core). The primary valve seat 6 and the secondary valve seat 5 form a new channel. At this time, the regulating effect of the valve during production is relatively small, and the channel between the secondary valve core (primary valve seat 6) and the secondary valve seat 5 (the annulus between the outer side of the primary valve seat 6 and the inner side of the secondary valve seat 5) can be controlled within a large opening range to ensure that the downhole medium can pass through quickly and shorten the entire production cycle.

[0032] The above-mentioned gas wellhead electric valves can be further optimized and / or improved according to actual needs: Example 2: As an optimization of the above examples, as shown in the appendix. Figures 2 to 5 As shown, a valve cover 13 is fixedly installed inside the control through hole, and a sealing packing 14 is provided between the outer side of the middle part of the valve stem 9 and the inner side of the valve cover 13. The drive assembly is fixedly installed on the upper side of the valve cover 13.

[0033] Depending on the requirements, the first end of inlet 3 is located at the left end of valve body 1, the second end of inlet 3 is connected to the upper part of valve cavity 2, the first end of outlet 4 is located at the lower end of valve body 1, the second end of outlet 4 is connected to the lower part of valve cavity 2, and the secondary valve seat 5 is located in valve cavity 2 between the second end of inlet 3 and the second end of outlet 4. In this way, valve body 1 is a needle valve body, which can adjust the flow rate. Alternatively, the first end of inlet 3 is located at the left end of valve body 1, the second end of inlet 3 is connected to the lower part of valve cavity 2, the first end of outlet 4 is located at the right end of valve body 1, the second end of outlet 4 is connected to the upper part of valve cavity 2, and the secondary valve seat 5 is located in valve cavity 2 between the second end of inlet 3 and the second end of outlet 4. In this way, valve body 1 is a shut-off valve body, and the outer side of the middle part of valve stem 9 is screwed into valve cover 13. Rotating valve stem 9 can also adjust the flow rate.

[0034] During use, the valve cover 13 facilitates the installation of the valve stem 9. By setting the sealing packing 14, the valve cover 13 and the valve stem 9 can be sealed, thereby improving the sealing performance of the gas wellhead electric valve.

[0035] Example 3: As an optimization of the above examples, as shown in the appendix. Figures 2 to 5 As shown, an outer ring platform 15 is fixed on the lower outer side of the first-stage valve seat 6 corresponding to the position below the guide hole 10. The valve cover 13 has a downward-facing mounting groove at the center of its lower end. A support plate 16 fitted onto the outside of the valve stem 9 is fixedly installed in the mounting groove. An elastic reset member 7 is installed between the upper end of the outer ring platform 15 and the lower end of the support plate 16.

[0036] During use, by setting the outer ring platform 15, the contact area between the first-stage valve seat 6 and the second-stage valve seat 5 can be increased. After the valve stem 9 moves downward, the sealing performance between the first-stage valve seat 6 and the second-stage valve seat 5 can be improved. By setting the support plate 16, the wear of the upper end of the elastic reset member 7 on the valve cover 13 can be avoided, which would affect the sealing performance between the valve cover 13 and the valve stem 9, as well as between the valve cover 13 and the valve body 1. This facilitates the maintenance of the gas wellhead electric valve and reduces maintenance costs.

[0037] Example 4: As an optimization of the above examples, as shown in the appendix. Figure 1 , 6 As shown, the drive assembly includes an electric actuator 17 and a connecting assembly. The connecting assembly includes a mounting plate 18 and a positioning mechanism. The mounting plate 18 is located above the valve cover 13. Several positioning mechanisms are spaced circumferentially on the lower side of the mounting plate 18. The lower side of each positioning mechanism is fixedly mounted to the upper side of the valve cover 13. The electric actuator 17 is fixedly mounted on the upper side of the mounting plate 18. The output shaft of the electric actuator 17 is connected to the upper end of the valve stem 9 via a transmission connection.

[0038] Depending on the requirements, the electric actuator 17 is a known prior art technology, such as the RST-QT20 linear electric actuator, a partial-turn electric actuator, or a multi-turn electric actuator. In this embodiment, the electric actuator 17 is a linear electric actuator. During use, this configuration allows for quick disassembly and assembly between the drive assembly and the valve body 1, facilitating subsequent valve maintenance. The electric actuator 17 can be remotely controlled or controlled on-site, and can simultaneously achieve both remote automatic and on-site manual operation modes, which can effectively reduce the intensity of manual labor and improve production efficiency. The electric actuator 17 can also customize the production system according to the well conditions to realize the automated control of the gas well. The gas wellhead electric valve can realize the shut-off function and can be used as a shut-off needle valve when the gas well is not in production. The gas wellhead electric valve has a double valve seat. The first-stage valve core (valve core 12 at the lower end of valve stem 9) and the first-stage valve seat 6 have good adjustment functions, which can effectively control the downstream pressure and effectively avoid the freezing and blockage of the downstream pipeline. The second-stage valve core (first-stage valve seat 6) and the second-stage valve seat 5 have a large flow channel, which improves production efficiency and shortens the well opening production time.

[0039] Example 5: As an optimization of the above examples, as shown in the appendix. Figure 1 , 6As shown in Figure 7, the positioning mechanism includes a screw 19, a mounting sleeve 20, a positioning head 21, a positioning sleeve 22, and a threaded sleeve 23. The upper side of the valve cover 13 is provided with at least two vertically penetrating lower mounting holes spaced circumferentially. A threaded sleeve 23 is fixedly installed in each lower mounting hole. The upper side of the mounting plate 18 corresponding to each lower mounting hole position is provided with a vertically penetrating upper mounting hole. Each upper mounting hole contains a screw 19, the lower outer part of which is screwed into the threaded sleeve 23 at the corresponding position. A threaded sleeve 23 is fitted onto the outer side of each screw 19. Mounting sleeve 20, each mounting sleeve 20 is fitted into the upper mounting hole of the corresponding position. Each mounting sleeve 20 is fixedly mounted with a positioning head 21 on the lower outer side. Each positioning head 21 is fitted with a positioning sleeve 22 whose lower end is fixedly mounted together with the upper side of the valve cover 13. The positioning sleeve 22 is provided with a radially penetrating insertion hole 24 on the outer side. The positioning head 21 corresponding to each insertion hole 24 is provided with a slot. Each insertion hole 24 is provided with a pin 25 whose end is inserted into the insertion hole 24 of the corresponding position.

[0040] To ensure the length of the threaded sleeve 23, a fixing plate can be fixedly installed on the upper side of the valve cover 13, and a lower mounting hole is located on the upper side of the fixing plate. The threaded sleeve 23 is fixedly installed in the lower mounting hole on the upper side of the fixing plate. During use, this design allows for quick assembly of the electric actuator 17 and the valve body 1, making the connection between the drive assembly and the valve body 1 more stable. It also improves the pressure-bearing capacity between the valve cover 13 and the valve body 1. During assembly, the valve stem 9 can be quickly and securely installed with the output shaft of the electric actuator 17, thereby improving assembly efficiency and solving the problem of cumbersome and time-consuming assembly of the electric actuator 17 and valve body 1 at the wellhead.

[0041] The process of installing the drive assembly is as follows: Install the mounting plate 18 onto the electric actuator 17; then fix the output shaft of the electric actuator 17 and the upper end of the valve stem 9 together using a known coupling; then align the mounting sleeve 20 with the positioning sleeve 22 on the upper side of the valve cover 13, and insert the mounting head into the corresponding mounting sleeve 20. After inserting the pin 25, the electric actuator 17 and the valve cover 13 are initially positioned; finally, rotate the screw 19 so that the lower end of the screw 19 is screwed into the threaded sleeve 23, and the upper end of the screw 19 contacts the upper side of the mounting plate 18 to achieve the fixed installation of the mounting plate 18 and the valve cover 13.

[0042] Example 6: As an optimization of the above examples, as shown in the appendix. Figure 1 , 6 As shown in Figures 7 and 8, limit rings 26 are fixedly installed on the outer side of the mounting sleeves 20 corresponding to the upper and lower positions of the mounting plate 18, and knobs 27 are fixedly installed on the upper end of the screw 19 corresponding to the position above the mounting plate 18.

[0043] Depending on the requirements, the knob 27 is hexagonal and is integrated with the screw 19. During use, the limit ring 26 can improve the connection strength between the mounting plate 18 and the mounting sleeve 20. The knob 27 facilitates the rotation of the screw 19, thereby fixing the mounting plate 18 and the valve cover 13 together.

[0044] Example 7: As an optimization of the above examples, as shown in the appendix. Figures 2 to 4 As shown, the upper outer side of the secondary valve seat 5 is screwed into the valve cavity 2. A limiting step is provided in the valve cavity 2 corresponding to the position below the secondary valve seat 5. A sealing gasket 28 is installed between the limiting step and the lower side of the secondary valve seat 5.

[0045] During use, this design facilitates the replacement of the secondary valve seat 5 after it wears out, and also makes it easier to install the secondary valve seat 5. The sealing gasket 28 can improve the sealing performance between the secondary valve seat 5 and the valve body 1.

[0046] Example 8: As an optimization of the above examples, as shown in the appendix Figures 1 to 8 As shown, the method of using the electric valve at the gas wellhead includes the following steps: S1, after removing the needle valve of the oil wellhead 29, install the electric valve at the gas wellhead; S2, when the production well is in intermittent production, the valve stem 9 is moved downward by the electric actuator 17, so that the valve core 12 closes the first-stage valve seat 6, and the first-stage valve seat 6 closes the second-stage valve seat 5, that is, the gas wellhead electric valve is in the closed state. S3, the pressure inside the production tree 29 pipe begins to build up. The pressure data inside the production tree 29 pipe is monitored. When the oil pressure inside the production tree 29 pipe reaches the set value, the valve stem 9 is moved upward by the electric actuator 17, the first-stage valve seat 6 opens the second-stage valve seat 5, and the production well begins this round of production. S4, set the opening of the first-stage valve seat 6 to the first set value and the second set value in sequence, and set the opening of the second-stage valve seat 5 to the third set value and the fourth set value in sequence; S5, the electric actuator 17 starts working and drives the valve stem 9 to move upward. After the valve stem 9 moves upward, the opening of the first-stage valve seat 6 gradually becomes the first set value. The pressure after the valve body 1 is monitored. If the pressure after the valve body 1 is greater than the set value, the output shaft of the electric actuator 17 rotates in the opposite direction, causing the valve stem 9 to move downward quickly and close the valve body 1. If the pressure after the valve body 1 is less than or equal to the set value, the opening of the valve body 1 remains unchanged after reaching the first set value. S6, after the first set time is continuously opened, the electric actuator 17 causes the valve stem 9 to continue to move upward. After the valve stem 9 moves upward, the opening of the first-stage valve seat 6 gradually changes from the first set value to the second set value. The opening of the valve body 1 remains unchanged after the second set value is reached. S7, after the second set time is continuously opened, the electric actuator 17 causes the valve stem 9 to continue to move upward. After the valve stem 9 moves upward, it drives the first-stage valve seat 6 to move upward, so that the opening of the second-stage valve seat 5 gradually changes to the third set value. After the opening of the valve body 1 reaches the third set value, it remains unchanged. S7, after the third set time is continuously opened, the electric actuator 17 causes the valve stem 9 to continue to move upward. After the valve stem 9 moves upward, it drives the first-stage valve seat 6 to move upward, so that the opening of the second-stage valve seat 5 gradually changes from the third set value to the fourth set value and then continues to produce. S8, monitor the pressure before valve body 1. If the pressure before valve body 1 is less than the production set value, the electric actuator 17 will activate and cause valve stem 9 to move downward. After valve stem 9 moves downward, valve body 1 will be closed until valve body 1 is completely closed, and this round of production will end.

[0047] In the normal state (valve closed), the valve core 12 (first-stage valve core) moves downward to the lowest point driven by the electric actuator 17, and the valve core 12 presses against the first-stage valve seat 6 (second-stage valve core) to achieve sealing and throttling between the valve core 12 and the first-stage valve seat 6; the first-stage valve seat 6 achieves sealing and throttling with the second-stage valve seat 5 under the action of the elastic reset element 7 and / or the valve core 12; the second-stage valve seat 5 and the valve body 1 are sealed by a sealing gasket 28; the valve core 12 and the valve cover 13 are sealed by a sealing packing 14 and a sealing ring. The sealing structures between valve core 12 and primary valve seat 6, and between primary valve seat 6 and secondary valve seat 5, are all metal sealing pairs (planar seal or conical seal). Since the medium flows from inlet 3 to outlet 4, there is a certain clamping force between valve core 12 and primary valve seat 6, and between primary valve seat 6 and secondary valve seat 5. In the initial state, it has a certain sealing performance. After the medium enters the valve body 1, as the pressure before the valve (on the inlet 3 side) increases, the clamping force between valve core 12 and primary valve seat 6, and between primary valve seat 6 and secondary valve seat 5 will slowly increase, and the sealing effect will gradually improve.

[0048] When the oil pressure in the well reaches a certain range, the valve needs to be opened for production. At this time, the electric actuator 17 starts to move, driving the valve stem 9 and valve core 12 to move upward. The gas wellhead electric valve enters the initial opening stage. At this time, only the valve core 12 drives the connecting pin 11 to move upward in the guide hole 10. The first-stage valve seat 6 is stationary under the action of the elastic reset member 7. The flow passage 8 between the valve core 12 and the first-stage valve seat 6 is opened. The valve core 12 can adopt a stepped shaft structure that gradually increases in size from bottom to top. The lower end face of the valve core 12 is a spherical crown surface. This allows for precise control during the well opening process and effectively solves the problems of excessive pressure after the valve (outlet 4 side) and freezing of the pipeline after the valve. At this time, the first-stage valve seat 6 and the second-stage valve seat 5 are still in a sealed closed state.

[0049] The electric actuator 17 continues to drive the valve stem 9 and valve core 12 upward, and the gas wellhead electric valve enters the subsequent opening stage. At this time, the valve stem 9 drives the connecting pin 11 to move to the upper end of the guide hole 10 and continues to move upward, thereby pulling the first-stage valve seat 6 to compress the elastic reset member 7 and continue to move upward. After the first-stage valve seat 6 separates from the second-stage valve seat 5, the channel between the first-stage valve seat 6 and the second-stage valve seat 5 opens. At this time, both channels open simultaneously. When the electric actuator 17 reaches the stroke set by the electric actuator 17, the electric actuator 17 stops operating. At this time, the flow area reaches the maximum value, improving production efficiency and shortening production time.

[0050] As the gas well produces gas, the downhole pressure gradually decreases. When the pressure drops to the set value, the well is considered unable to continue production and needs to be shut in to maintain pressure. At this time, the electric actuator 17 starts to move, driving the valve stem 9 and valve core 12 to move downward. Under the action of the elastic reset member 7, the first-stage valve seat 6 moves downward first and then closes the channel between it and the second-stage valve seat 5. The valve core 12 continues to move downward and closes the flow channel 8 between it and the first-stage valve seat 6. At this time, the electric actuator 17 stops moving, and the gas wellhead electric valve is in a completely sealed closed state.

[0051] In use, the manual needle valve of the production tree 29 is replaced with the gas wellhead electric valve of this application. When the production well is in intermittent production in the later stage, the gas wellhead electric valve can be used as a needle valve. The gas wellhead electric valve is in the closed state to carry out the pressure build-up process in the production tree 29. By monitoring the pressure in front of the valve through the gas wellhead electric valve, when the pressure in front of the valve reaches a certain value and the production conditions are met, the current round of production can be carried out through the gas wellhead electric valve. To set the valve seat opening of the gas wellhead electric valve core 12, the electric actuator 17 can be connected to an existing known controller (such as a control valve controller or PLC). Parameters can be set through the control valve controller or PLC or on the electric actuator 17, such as the first set value, second set value, third set value, fourth set value, first set time, first set time, second set time, and third set time. The valve core 12 opens the first-stage valve seat 6 in two steps: first, it opens to 40% (first set value), and then it opens to 100% (second set value). The opening of the second-stage valve seat 5 by the first-stage valve seat 6 also takes two steps: first, it opens to 50% (third set value), and then it opens to 100% (fourth set value). The first, second, third, and fourth set values ​​can also be set according to requirements.

[0052] After setting, the valve is opened for the first time. The opening degree of the first-stage valve seat 6 of the gas wellhead electric valve is 40%. During the well opening process, the pressure after the valve is observed at any time. If the pressure after the valve is greater than 4MPa (production set value), the gas wellhead electric valve stops opening and closes instantly (the gas wellhead electric valve enters protection mode) to protect the downstream pipeline and emergency shut-off valve 30 and prevent the emergency shut-off valve 30 from closing. If the pressure after the valve is normal and stable, production will be carried out at this opening degree for 10 to 20 minutes (first set time).

[0053] The valve is opened for the second time. The first-stage valve seat 6 of the gas wellhead electric valve is opened to 100%. During this process, the valve will generally not be closed due to excessive pressure after the valve. Production will continue for 25 to 35 minutes at this opening (second set time).

[0054] The valve is opened for the third time. The secondary valve seat 5 of the electric valve at the gas wellhead is opened to 50%. At this stage, the valve has entered the main production process with a large flow rate. After running for 10 minutes (the third set time), the next stage can be carried out.

[0055] The fourth valve opening is performed, with the secondary valve seat 5 of the gas wellhead electric valve opening to 100%. At this point, all channels of the gas wellhead electric valve are open, maximizing production capacity, and production can continue continuously. During production, the pressure upstream of the valve can be monitored in real time. When the upstream pressure falls below a set pressure value (which can be set based on production experience), the well's production capacity is considered insufficient. Both upstream and downstream pressures are collected by pressure sensors and transmitted to the PLC. The PLC connects to a host computer, where first, second, third, and fourth set values, as well as first, second, and third set times, are set. After receiving the data, the PLC can remotely control the electric actuator 17, making control more convenient. The gas wellhead electric valve will automatically close, returning from a fully open to a fully closed state, thus ending one production cycle.

[0056] The above technical features constitute various embodiments of the present invention, which have strong adaptability and implementation effect. Unnecessary technical features can be added or removed according to actual needs to meet the needs of different situations.

Claims

1. An electric valve for gas wellheads, characterized in that... The valve assembly includes a valve body, valve stem, drive assembly, and sealing core assembly. The valve body has a valve cavity, with an inlet and an outlet on the outside. The other ends of both the inlet and outlet communicate with the valve cavity. A secondary valve seat is located within the valve cavity between the inlet and outlet. A sealing core assembly is located on the upper side of the secondary valve seat. The sealing core assembly includes a primary valve seat, a resilient reset element, and a connecting pin. A primary valve seat, with its upper end positioned above the secondary valve seat, is located on the inner side of the upper part of the secondary valve seat. A flow passage, with its lower end communicating with the outlet, is located on the upper side of the valve body corresponding to the primary valve seat. A control channel, communicating with the valve cavity, is located on the upper side of the valve body at the position of the primary valve seat. A sealing core assembly is located within the control channel. The valve is equipped with a valve stem that can move up and down. An elastic reset element is installed between the lower outer side of the valve stem and the first-stage valve seat. Several strip-shaped guide holes with internal and external communication are evenly distributed circumferentially on the upper outer side of the first-stage valve seat. A connecting pin with its end fixed to the outer side of the valve stem is slidably installed in each guide hole. A valve core is fixed at the lower end of the valve stem corresponding to the position below the connecting pin. When the valve core moves downward, it can close the flow passage. When the valve core moves upward, it can open the flow passage or create a gap between the lower end of the first-stage valve seat and the upper end of the second-stage valve seat. A drive assembly that enables the valve stem to move up and down is provided on the upper side of the valve body.

2. The gas wellhead electric valve according to claim 1, characterized in that... A valve cover is fixedly installed inside the control through hole, and a sealing packing is provided between the outer side of the middle part of the valve stem and the inner side of the valve cover. The drive assembly is fixedly installed on the upper side of the valve cover.

3. The gas wellhead electric valve according to claim 2, characterized in that... An outer ring platform is fixed on the lower outer side of the first-stage valve seat corresponding to the position below the guide hole. A downward-opening mounting groove is provided at the center of the lower end of the valve cover. A support plate fitted on the outside of the valve stem is fixedly installed in the mounting groove. An elastic reset component is installed between the upper end of the outer ring platform and the lower end of the support plate.

4. The gas wellhead electric valve according to claim 2 or 3, characterized in that... The drive assembly includes an electric actuator and a connecting component. The connecting component includes a mounting plate and a positioning mechanism. The mounting plate is located above the valve cover. Several positioning mechanisms are spaced circumferentially on the lower side of the mounting plate. The lower side of each positioning mechanism is fixedly mounted to the upper side of the valve cover. The electric actuator is fixedly mounted on the upper side of the mounting plate. The output shaft of the electric actuator is connected to the upper end of the valve stem via a drive connection.

5. The gas wellhead electric valve according to claim 4, characterized in that... The positioning mechanism includes a screw, a mounting sleeve, a positioning head, a positioning sleeve, and a threaded sleeve. At least two vertically penetrating lower mounting holes are spaced circumferentially on the upper side of the valve cover. A threaded sleeve is fixedly installed in each lower mounting hole. An upper mounting hole is provided on the upper side of the mounting plate corresponding to each lower mounting hole. A screw, with its lower outer side screwed into the corresponding threaded sleeve, is provided in each upper mounting hole. A mounting sleeve is fitted onto the outer side of each screw. The upper part of each mounting sleeve is fitted into the corresponding upper mounting hole. A positioning head is fixedly installed on the lower outer side of each mounting sleeve. A positioning sleeve, with its lower end fixedly installed to the upper side of the valve cover, is fitted onto the outer side of each positioning head. A radially penetrating insertion hole is provided on the outer side of the positioning head corresponding to each insertion hole. A slot is provided on the outer side of each insertion hole. A pin, with its end inserted into the corresponding insertion hole, is provided in each insertion hole.

6. The gas wellhead electric valve according to claim 5, characterized in that... Limiting rings are fixedly installed on the outer side of the mounting sleeves at the upper and lower positions of the mounting plate, and a knob is fixedly installed on the upper end of the screw at the upper position of the mounting plate.

7. The gas wellhead electric valve according to claim 1, 2, 3, 5, or 6, characterized in that... The upper outer side of the secondary valve seat is screwed into the valve cavity. A limiting step is provided in the valve cavity corresponding to the position below the secondary valve seat. A sealing gasket is installed between the limiting step and the lower side of the secondary valve seat.

8. The gas wellhead electric valve according to claim 4, characterized in that... The upper outer side of the secondary valve seat is screwed into the valve cavity. A limiting step is provided in the valve cavity corresponding to the position below the secondary valve seat. A sealing gasket is installed between the limiting step and the lower side of the secondary valve seat.

9. A method of using an electric valve at the gas wellhead according to any one of claims 1 to 8, characterized in that... The steps include the following: S1, after removing the needle valve from the oil wellhead, install the electric valve at the gas wellhead; S2, when the production well is in intermittent production, the valve stem is moved downward by the electric actuator, so that the valve core closes the first-stage valve seat, and the first-stage valve seat closes the second-stage valve seat, that is, the electric valve at the gas wellhead is in the closed state. S3, the pressure inside the production tree begins to build up. The pressure data inside the production tree is monitored. When the oil pressure inside the production tree reaches the set value, the valve stem moves upward through the electric actuator, the first-stage valve seat opens the second-stage valve seat, and the production well begins this round of production. S4, set the opening of the first-stage valve seat to the first set value and the second set value in sequence, and set the opening of the second-stage valve seat to the third set value and the fourth set value in sequence; S5, the electric actuator starts working and drives the valve stem to move upward. After the valve stem moves upward, the opening of the first-stage valve seat gradually becomes the first set value, and the opening of the valve body remains unchanged after reaching the first set value. S6, after the first set time is continuously opened, the electric actuator causes the valve stem to continue to move upward. After the valve stem moves upward, the opening of the first-stage valve seat gradually changes from the first set value to the second set value. The opening of the valve body remains unchanged after the second set value is reached. S7, after the second set time is continuously opened, the electric actuator causes the valve stem to continue to move upward. After the valve stem moves upward, it drives the first-stage valve seat to move upward, causing the opening of the second-stage valve seat to gradually change to the third set value. The opening of the valve body remains unchanged after reaching the third set value. S7, after the third set time is continuously opened, the electric actuator causes the valve stem to continue to move upward. After the valve stem moves upward, it drives the first-stage valve seat to move upward, so that the opening of the second-stage valve seat gradually changes from the third set value to the fourth set value and then continues production. S8 monitors the pressure before the valve body. If the pressure before the valve body is less than the production set value, the electric actuator will activate and cause the valve stem to move downward. After the valve stem moves downward, the valve body will be closed until the valve body is completely closed, and the current production cycle will end.

10. The method of using the gas wellhead electric valve according to claim 9, characterized in that... Step S5 is as follows: The electric actuator starts working and drives the valve stem to move upward. After the valve stem moves upward, the opening of the first-stage valve seat gradually becomes the first set value. The pressure after the valve body is monitored. If the pressure after the valve body is greater than the set value, the output shaft of the electric actuator rotates in the opposite direction, causing the valve stem to move downward quickly and close the valve body. If the pressure after the valve body is less than or equal to the set value, the opening of the valve body remains unchanged after reaching the first set value.

Images