Self-cleaning type wellhead emergency cut-off valve and cut-off method

Abstract

The invention discloses a self-cleaning type wellhead emergency cut-off valve and a cut-off method, and belongs to the field of oil exploitation equipment. The invention provides a self-cleaning type wellhead emergency cut-off valve which comprises a valve body, a valve rod is arranged in the valve body, a sealing piece is arranged between the valve rod and the valve body, shearing pieces are arranged below the valve rod and comprise the upper shearing piece and the lower shearing piece, the upper shearing piece is connected with the valve rod through a connecting pin, and the lower shearing piece is connected with the valve rod through a connecting pin. The lower shearing piece is fixedly connected with the inner wall of the valve body, and through holes are formed in the upper shearing piece and the lower shearing piece. The device has a flow display function, an overpressure and pressure loss emergency automatic cut-off function and an emergency shutdown function when the temperature is abnormal and the concentration of combustible gas is abnormal. The upper shearing piece and the lower shearing piece are sealed through wear-resistant mirror faces, the sealing faces have the self-cleaning function, and zero leakage can be achieved under the working condition of ultrahigh pressure difference.

Description

Technical Field

[0001] The invention belongs to the technical field of petroleum production equipment and relates to a self-cleaning wellhead emergency cut-off valve. Background Art

[0002] In oil production, each well must be installed with at least one set of emergency shut-off equipment, which is widely used in oil fields. At present, most of the shut-off valves used in oil field production are basically pipeline emergency shut-off valves. Pipeline emergency shut-off valves are divided into three valve structures: ball valves, butterfly valves, and gate valves. If foreign objects are stuck in the shut-off structure during the operation of these valves, the valves cannot be completely closed or the valve closing function fails completely, which will cause major on-site accidents, leading to large-scale losses and safety accidents. Summary of the invention

[0003] The purpose of the present invention is to solve the problem that the emergency shut-off valve is stuck by foreign objects, which makes it difficult to shut down. In order to solve the above technical problems, the present invention provides a self-cleaning wellhead emergency shut-off valve and a shut-off method thereof, which uses a sharp-angle cut formed by cemented carbide to cut off foreign objects stuck in the valve, and adopts an integrated intelligent electric actuator to realize real-time monitoring and control of the valve opening.

[0004] On the one hand, the present invention provides a self-cleaning wellhead emergency shut-off valve, comprising a valve body, a valve stem being arranged in the valve body, a sealing member being arranged between the valve stem and the valve body, a shear piece being arranged under the valve stem, the shear piece comprising an upper shear piece and a lower shear piece, the upper shear piece being connected to the valve stem by a connecting pin, the lower shear piece being fixedly connected to the inner wall of the valve body, and through holes being arranged on both the upper shear piece and the lower shear piece.

[0005] Furthermore, the contact surfaces between the upper shearing piece and the lower shearing piece of the present invention are both wear-resistant mirror surfaces.

[0006] Furthermore, an acute-angle cut is provided between the upper shearing piece and the lower shearing piece of the present invention.

[0007] Furthermore, a valve cover is provided on the upper part of the valve body of the present invention, and the valve cover is sleeved on the outside of the valve stem, and a deep groove ball bearing is provided between the valve stem and the inside of the valve body.

[0008] Furthermore, the valve body of the present invention is also provided with a feed pipe and a discharge pipe, the feed pipe is connected to the upper part of the upper shearing piece, and the discharge pipe is connected to the lower part of the lower shearing piece.

[0009] Furthermore, the feed pipe of the present invention is provided with an air inlet flange, and the discharge pipe is provided with an air outlet flange.

[0010] Furthermore, in the present invention, an integrated intelligent electric actuator is provided at one end of the valve stem away from the valve body, and the integrated intelligent electric actuator includes an electric actuator and an intelligent controller, and the electric actuator and the intelligent controller are electrically connected.

[0011] Furthermore, the feed pipe of the present invention is provided with a flow detection sensor and a pressure detection sensor, and the flow detection sensor and the pressure detection sensor are electrically connected to the intelligent controller.

[0012] Furthermore, the discharge pipe of the present invention is provided with a combustible gas detection sensor, and the combustible gas detection sensor is electrically connected to the intelligent controller. The feed pipe is provided with a temperature sensor, and the temperature sensor is electrically connected to the intelligent controller.

[0013] The present invention adopts an explosion-proof structural design, and the electric actuator has an output with a 200-level reduction ratio.

[0014] The upper shearing piece and the lower shearing piece of the present invention are made of hard alloy. Preferably, the upper shearing piece and the lower shearing piece are made of high-hardness tungsten alloy steel with a hardness of 95HRA.

[0015] The intelligent controller of the present invention has a built-in RS485 signal output port.

[0016] Furthermore, a mechanical limit structure and an opening display module are provided on the valve stem of the intelligent electric actuator described in the present invention, and the opening display module adopts a valve position opening meter.

[0017] Furthermore, the mechanical limiting mechanism of the present invention is a ratchet structure, and the intelligent electric actuator adopts a servo motor with an angle control mode.

[0018] In a second aspect, the present invention provides a wellhead emergency shut-off method, the method comprising:

[0019] Detect the pressure signal, flow signal of the fluid inlet and the combustible gas concentration signal of the fluid outlet. When one or more of them are abnormal, start the intelligent electric actuator to push the valve stem to rotate quickly to emergency cut off the passage;

[0020] When the abnormal signal is that the flow rate decreases within 0.3-1s and the pressure signal increases, push the valve stem to rotate quickly to cut off the passage, and open the passage again after the flow rate is zero and the pressure is stable for 0.3-1s; if the flow rate still decreases within 1-5s and the pressure signal increases, continue to repeatedly cut off and open until the flow rate and pressure are stable and stop the operation;

[0021] When the abnormal signal is that the pressure signal and the flow signal continue to increase within 0.5-1s, the valve stem is pushed to rotate quickly to cut off the passage until the pressure signal returns to normal or the passage is opened after manual detection;

[0022] When the pressure signal and flow signal in the abnormal signal are normal, and the combustible gas concentration signal continues to increase within 0.2-0.5s, the valve stem is pushed to rotate quickly to cut off the passage until the pressure signal returns to normal or the passage is opened after manual detection;

[0023] When the abnormal signal is that the flow rate increases within 0.5-1s and the pressure signal decreases, the valve stem is pushed to rotate quickly to cut off the passage, and the passage is opened after manual inspection.

[0024] Compared with the prior art, the technical solution provided by the present invention has at least the following beneficial effects or advantages:

[0025] The self-cleaning wellhead emergency shut-off valve provided by the present invention is mainly used to improve the emergency shut-off valve device at the natural gas well and the oil wellhead, and can more effectively prevent the shut-off failure caused by foreign matter stuck at the valve shut-off point from causing large-scale safety accidents.

[0026] The valve seal of the present invention is composed of two high-hardness alloy sheets. If foreign matter gets stuck when the valve is closed urgently, wood, plastic, stone and ordinary metal can be removed by the alloy sheets by rotating shearing. The present invention adopts a sharp-angle shearing mouth. The medium pressure and mechanical pressure can well promote the meshing force of the scissors mouth. The explosion-proof structural design plus the execution structure with a 200-level reduction ratio can facilitate the cutting off of more than 95% of foreign matter, solving the problem of the existing valve body structure being easily stuck by foreign matter.

[0027] The invention has a flow display function, an overpressure and underpressure emergency automatic cutoff function, and an abnormal temperature and abnormal combustible gas concentration emergency shutdown function.

[0028] The valve sealing form of the present invention is a wear-resistant mirror alloy sheet seal, the sealing surface has a self-cleaning function, and can achieve zero leakage under ultra-high pressure difference working conditions.

[0029] The present invention can realize remote control of valves, implement intermittent operation, scheduled operation, and reduce labor costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 A schematic diagram of the structure of a self-cleaning wellhead emergency shut-off valve provided by the present invention;

[0031] Figure 2 for Figure 1 A schematic diagram of the structure of the shear piece shown;

[0032] Figure 3 for Figure 2 The schematic diagram of the local structure of the shear piece shown;

[0033] Figure 4 It is a schematic diagram of the ratchet structure of the present invention.

[0034] Numbers in the figure: 1-air inlet flange, 2-flow detection sensor, 3-pressure detection sensor, 4-integrated intelligent electric actuator, 4.1-intelligent controller, 4.2-electric actuator, 5-valve body, 5.1-valve cover, 5.2-deep groove ball bearing, 5.3-valve stem, 5.4-seal, 5.5-connecting pin, 5.6-shear piece, 6-combustible gas detection sensor, 7-air outlet flange, 8-upper shear piece, 9-lower shear piece, 10-foreign matter, 11-ratchet structure. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0036] The specific implementation of the present invention is described in detail below in conjunction with specific embodiments.

[0037] Example 1

[0038] See also Figures 1 to 4 The present invention provides a self-cleaning wellhead emergency shut-off valve, comprising a valve body 5, a valve stem 5.3, a valve cover 5.1, a feed pipe, a discharge pipe and an integrated intelligent electric actuator 4, wherein the valve stem 5.3 passes through the valve cover 5.1 and is inserted into the valve body 5, a seal 5.4 and a deep groove ball bearing 5.2 are arranged between the valve stem 5.3 and the valve body 5, a shearing piece 5.6 is arranged under the valve stem 5.3, and the shearing piece 5.6 comprises an upper shearing piece 8 and a lower shearing piece 9, the upper shearing piece 8 is connected to the valve stem 5.3 by a connecting pin 5.5, the lower shearing piece 9 is fixedly connected to the inner wall of the valve body 5, and the upper shearing piece 8 and the lower shearing piece 9 are both provided with through holes, and the through holes of the upper shearing piece 8 are arranged correspondingly to the through holes of the lower shearing piece 9. The aperture of the through holes of the upper shearing piece 8 and the lower shearing piece 9 located on the contact surface of the upper shearing piece 8 and the lower shearing piece 9 is smaller than the aperture away from the contact surface of the upper shearing piece 8 and the lower shearing piece 9. The feed pipe passes through the side wall of the valve body 5 and is communicated with the through hole opening of the upper shear piece 8 away from the contact surface of the upper shear piece 8 and the lower shear piece 9, and the discharge pipe passes through the side wall of the valve body 5 and is communicated with the through hole opening of the lower shear piece 9 away from the contact surface of the upper shear piece 8 and the lower shear piece 9. The present invention realizes valve closing by aligning and staggering the opening and closing of the through holes between the upper shear piece 8 and the lower shear piece 9. The valve body 5 of the present invention is threadedly connected by the valve cover 5.1 to press the deep groove ball bearing 5.2, and the deep groove ball bearing 5.2 presses the valve stem 5.3. The valve body 5 is sealed by the seal 5.4 to cut off the space between the upper shear piece 8 and the deep groove ball bearing 5.2 to avoid leakage of the transmitted fluid.

[0039] The contact surfaces between the upper shearing piece 8 and the lower shearing piece 9 of the present invention are both wear-resistant mirror surfaces. The wear-resistant mirror surface of the present invention realizes surface sealing, and the sealing surface is rubbed back and forth and is very smooth, so that it has a self-cleaning function and can achieve zero leakage under ultra-high pressure difference conditions.

[0040] The upper shearing piece 8 and the lower shearing piece 9 of the present invention are made of 95HRA high hardness alloy tungsten steel, and an acute angle cut is provided between the upper shearing piece 8 and the lower shearing piece 9. Figure 3 The R is less than 90°). When the foreign matter 10 stuck in the valve body 5 is wood, plastic, stone or ordinary metal, it can be removed by the upper shearing piece 8 and the lower shearing piece 9 of the alloy material by rotary shearing. The sharp-angle shearing mouth, the medium pressure of the fluid and the mechanical pressure of the valve stem provide a good meshing force to promote the shearing mouth. The explosion-proof structure design plus the execution structure of the 200-level reduction ratio can facilitate the cutting of more than 95% of foreign matter, ensuring that the valve can still be closed smoothly after the foreign matter is stuck.

[0041] The feed pipe of the present invention is provided with an air inlet flange 1, and the discharge pipe is provided with an air outlet flange 7. The air inlet flange 1, the air outlet flange 7, the discharge pipe, the feed pipe and the valve body 5 are an integrated structure manufactured by welding.

[0042] The valve stem 5.3 of the present invention is provided with an integrated intelligent electric actuator 4 at one end away from the valve body 5, and the integrated intelligent electric actuator 4 includes an electric actuator 4.2 and an intelligent controller 4.1. The feed pipe of the present invention is threadedly connected with a flow detection sensor 2, a temperature sensor and a pressure detection sensor 3, and the flow detection sensor 2, the temperature sensor and the pressure detection sensor 3 are electrically connected to the intelligent controller 4.1. The discharge pipe of the present invention is threadedly connected with a combustible gas detection sensor 6, and the combustible gas detection sensor 6 is electrically connected to the intelligent controller 4.1. The electric actuator 4.2 is electrically connected to the intelligent controller 4.1, and the valve stem 5.3 is connected to the output shaft of the electric actuator.

[0043] The intelligent controller 4.1 of the present invention can process various signals: when overpressure or underpressure occurs, the intelligent controller 4.1 cuts off the valve through the intelligent electric actuator 4.2 to achieve shutdown; through the flow signal, the user can remotely control the gas output to achieve intermittent gas production, timed gas production, and unattended operation; when encountering overtemperature or excessive concentration of combustible gas, there is a risk of flammability, the intelligent controller 4.1 cuts off the valve through the intelligent electric actuator 4.2 to achieve shutdown.

[0044] The intelligent controller of the present invention has a built-in RS485 signal output port, which can transmit the flow, pressure, temperature, and combustible gas concentration of the present invention to the system background, thereby realizing remote control of the valve and realizing intermittent operation and scheduled operation.

[0045] The valve stem 5.3 of the intelligent electric actuator 4.2 described in the present invention is provided with a mechanical limit structure and an opening display module, and the opening display module adopts a valve position opening meter. The mechanical limit mechanism of the present invention is a ratchet structure 11, and the ratchet structure 11 is arranged at a position close to the valve cover 5.1. The ratchet structure 11 is connected to the valve stem 5.3 through a positioning pin. The ratchet structure 11 can prevent the upper shear plate 8 from being pushed by the medium pressure to reverse and change the valve opening. The intelligent electric actuator adopts a servo motor with an angle control mode, and an encoder and other structures calculate the angle command of the servo motor rotation. This enables the present invention to adjust the flow rate and realize valve closing within 1 second.

[0046] Example 2

[0047] The present invention provides a wellhead emergency cut-off method, the method comprising:

[0048] Detect the pressure signal, flow signal of the fluid inlet and the combustible gas concentration signal of the fluid outlet. When one or more of them are abnormal, start the intelligent electric actuator 4.2 to push the valve stem 5.3 to rotate quickly to emergency cut off the passage;

[0049] When the abnormal signal is that the flow rate decreases within 0.3-1s and the pressure signal increases, push the valve stem 5.3 to rotate quickly to cut off the passage, and open the passage again after the flow rate is zero and the pressure is stable for 0.3-1s; if the flow rate still decreases within 1-5s and the pressure signal increases, continue to repeatedly cut off and open until the flow rate and pressure are stable and stop the operation;

[0050] When the abnormal signal is that the pressure signal and the flow signal continue to increase within 0.5-1s, the valve stem 5.3 is pushed to rotate quickly to cut off the passage until the pressure signal returns to normal or the passage is opened after manual detection;

[0051] When the pressure signal and flow signal in the abnormal signal are normal, and the combustible gas concentration signal continues to increase within 0.2-0.5s, the valve stem 5.3 is pushed to rotate quickly to cut off the passage until the pressure signal returns to normal or the passage is opened after manual detection;

[0052] When the abnormal signal is that the flow rate increases within 0.5-1s and the pressure signal decreases, the valve stem 5.3 is pushed to rotate quickly to cut off the passage, and the passage is opened after manual inspection.

[0053] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A self-cleaning wellhead emergency shut-off valve, characterized in that: It includes a valve body, a valve stem is arranged in the valve body, a sealing member is arranged between the valve stem and the valve body, a shear piece is arranged under the valve stem, the shear piece includes an upper shear piece and a lower shear piece, the upper shear piece is connected to the valve stem by a connecting pin, the lower shear piece is fixedly connected to the inner wall of the valve body, and through holes are arranged on the upper shear piece and the lower shear piece.

2. A self-cleaning wellhead emergency shut-off valve according to claim 1, characterized in that: The contact surfaces between the upper shearing piece and the lower shearing piece are both wear-resistant mirror surfaces.

3. A self-cleaning wellhead emergency shut-off valve according to claim 1, characterized in that: An acute-angle cut is provided between the upper shearing piece and the lower shearing piece.

4. A self-cleaning wellhead emergency shut-off valve according to claim 1, characterized in that: A valve cover is provided on the upper part of the valve body, and the valve cover is sleeved on the outside of the valve stem. A deep groove ball bearing is provided between the valve stem and the inside of the valve body.

5. A self-cleaning wellhead emergency shut-off valve according to claim 1, characterized in that: The valve body is also provided with a feed pipe and a discharge pipe, wherein the feed pipe is connected to the upper portion of the upper shearing piece, and the discharge pipe is connected to the lower portion of the lower shearing piece.

6. A self-cleaning wellhead emergency shut-off valve according to claim 5, characterized in that: The feed pipe is provided with an air inlet flange, and the discharge pipe is provided with an air outlet flange.

7. A self-cleaning wellhead emergency shut-off valve according to claim 5, characterized in that: An integrated intelligent electric actuator is provided at one end of the valve stem away from the valve body. The integrated intelligent electric actuator comprises an electric actuator and an intelligent controller. The electric actuator and the intelligent controller are electrically connected.

8. A self-cleaning wellhead emergency shut-off valve according to claim 7, characterized in that: The feed pipe is provided with a flow detection sensor and a pressure detection sensor, and the flow detection sensor and the pressure detection sensor are electrically connected to the intelligent controller.

9. A self-cleaning wellhead emergency shut-off valve according to claim 7, characterized in that: The discharge pipe is provided with a combustible gas detection sensor, and the combustible gas detection sensor is electrically connected to the intelligent controller.

10. A wellhead emergency shut-off method, characterized in that: The method is: Detect the pressure signal, flow signal of the fluid inlet and the combustible gas concentration signal of the fluid outlet. When one or more of them are abnormal, start the intelligent electric actuator to push the valve stem to rotate quickly to emergency cut off the passage; When the abnormal signal is that the flow rate decreases within 0.3-1s and the pressure signal increases, push the valve stem to rotate quickly to cut off the passage, and open the passage again after the flow rate is zero and the pressure is stable for 0.3-1s; if the flow rate still decreases within 1-5s and the pressure signal increases, continue to repeatedly cut off and open until the flow rate and pressure are stable and stop the operation; When the abnormal signal is that the pressure signal and the flow signal continue to increase within 0.5-1s, the valve stem is pushed to rotate quickly to cut off the passage until the pressure signal returns to normal or the passage is opened after manual detection; When the pressure signal and flow signal in the abnormal signal are normal, and the combustible gas concentration signal continues to increase within 0.2-0.5s, the valve stem is pushed to rotate quickly to cut off the passage until the pressure signal returns to normal or the passage is opened after manual detection; When the abnormal signal is that the flow rate increases within 0.5-1s and the pressure signal decreases, the valve stem is pushed to rotate quickly to cut off the passage, and the passage is opened after manual inspection.

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