A wellhead operation control valve

Abstract

The utility model belongs to the downhole operation equipment technical field of offshore oil engineering, disclose a wellhead operation control valve. The wellhead operation control valve includes the upper joint, the casing and the lower joint connected in proper order, is equipped with the soluble ball, the elastic pawl and the spring in casing inside and successively axial, the elastic pawl outer wall is equipped with the axial slit and is matched with the casing inside sliding section, this valve has three kinds of working positions: at the closed position, the spring pushes the elastic pawl and makes the soluble ball seal in the upper joint inclined plane, realizes pressure packoff, at the half open position, the first pressure pushes the soluble ball and the elastic pawl and moves down, the soluble ball is separated from the sealing surface, and fluid is circulated through the slit to establish a circulation channel, at the fully open position, the second pressure greater than the first pressure makes the elastic pawl abut the limiting step in casing and radially expand, and the soluble ball is released to drop. The utility model has compact structure, simple operation, and effectively improves the safety, efficiency and reliability of offshore workover operation.

Description

Technical Field

[0001] This utility model relates to the field of downhole operation equipment technology for offshore oil engineering, and specifically to a wellhead operation control valve. Background Technology

[0002] In offshore oil and gas field development, well workover is an important maintenance operation. During well workover, it is often necessary to remove the wellhead Christmas tree. After removal, in order to control downhole safety valves and venting valves during operations such as running tubing and to meet the process requirements of circulating flushing and well control, and wireline cutting tools, traditional technical solutions must reconnect the hydraulic control line from the tubing hanger to the control system on the drill table.

[0003] However, this existing method of reconnecting hydraulic control lines has several significant drawbacks: First, the hydraulic control lines need to traverse complex wellhead equipment, such as riser pipes and blowout preventer (BOP) assemblies. The traversal path is tortuous, space is limited, and connection and testing are time-consuming and labor-intensive, severely impacting operational efficiency. Second, during the process of reconnecting the tubing string to the tubing hanger, the exposed hydraulic control lines are easily squeezed, scratched, or even cut by moving tubing, leading to hydraulic failure. This necessitates pipeline replacement and rework, increasing non-productive time and costs. Third, the reconnected hydraulic control lines are usually exposed within the BOP assembly cavity. During critical BOP pressure tests (especially single-gate BOPs), these lines can affect the sealing of the test space, leading to unqualified or impossible pressure tests, thereby jeopardizing the reliability verification of the entire well control safety system.

[0004] Therefore, there is an urgent need for a device that can avoid the need for lengthy hydraulic control pipeline reconnections while also enabling wellhead pressure control and circulation establishment, in order to improve the safety, efficiency, and reliability of offshore well workover operations. Utility Model Content

[0005] In view of the shortcomings of the existing technology, this utility model proposes a wellhead operation control valve that can improve the safety, efficiency and reliability of offshore well workover operations.

[0006] The wellhead operation control valve according to this utility model includes: an upper connector for connecting to a lift tubing; a lower connector for hooking with a tubing; a housing connected between the upper and lower connectors to form an internal cavity, the internal cavity including an axially extending sliding section and a limiting step located below the sliding section; and a valve assembly, the valve assembly including a soluble ball axially arranged in sequence in the internal cavity, an elastic pawl abutting below the soluble ball, and a spring elastically abutting between the elastic pawl and the lower connector, the outer wall of the elastic pawl slidingly engaging with the sliding section, and at least one axial slit formed on its outer wall. The wellhead operation control valve has a closed position, a fully open position, and a semi-open position between the closed and fully open positions. In the closed position, the spring pushes the elastic pawl upward, causing the upper part of the elastic pawl to press the soluble ball against the sealing ramp inside the upper connector to isolate the pressure of the lower tubing string. In the semi-open position, the soluble ball and the elastic pawl, under the push of the first pressure, overcome the spring force and move downward, causing the soluble ball to detach from the sealing ramp, and the fluid flows through the slot to establish a circulation channel. In the fully open position, the soluble ball and the elastic pawl, under the action of a second pressure greater than the first pressure, move downward until the elastic pawl abuts against the limiting step, and the outer wall of the elastic pawl expands outward under the action of the second pressure to release the grip on the soluble ball, causing the soluble ball to fall off.

[0007] Furthermore, the resilient pawl includes an annular base for sealing abutting against the soluble ball and at least two resilient flaps extending downward from the annular base, with at least one axial slit formed between adjacent resilient flaps.

[0008] Furthermore, the annular base is constructed as an arc-shaped groove or spherical socket structure that seals against the soluble sphere.

[0009] Furthermore, the elastic flap includes a sliding engagement section located at its bottom for abutting against the limiting step and a connecting section connecting the sliding engagement section and the annular base. The outer diameter of the sliding engagement section is the same as the inner diameter of the sliding section, and the outer diameter of the connecting section is smaller than the inner diameter of the sliding section.

[0010] Furthermore, the resilient pawl is made of spring steel, stainless steel, or beryllium bronze.

[0011] Furthermore, the soluble balls are made of materials that can dissolve in the wellbore working fluid.

[0012] Furthermore, the material of the soluble sphere is a magnesium alloy, an aluminum alloy, or a soluble polymer.

[0013] Furthermore, the wellhead operation control valve also includes an anti-backlash pin, which is connected to the connection between the upper connector and the housing, as well as the connection between the housing and the lower connector.

[0014] Furthermore, the sealing bevel inside the upper connector is a conical surface.

[0015] Furthermore, the lower connector has standard API threads for connecting tubing hooks.

[0016] Compared with existing technologies, the wellhead operation control valve of this invention, by being directly installed on the tubing hanger, eliminates the need for external pipelines, saving significant non-productive time spent traversing, connecting, and testing pipelines, and avoiding rework caused by damage from external pipelines, thus significantly improving operational efficiency. Furthermore, the wellhead operation control valve of this invention features a simple mechanical structure, making operation more convenient. It provides precise and reliable step-by-step pressure control, eliminates the need to handle fragile pipelines, and the soluble ball automatically dissolves without residue, effectively reducing operational complexity and risk, and comprehensively improving functional reliability. Attached Figure Description

[0017] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1 A schematic diagram of the wellhead operation control valve according to the present invention in the closed position is shown; Figure 2 A schematic diagram of the wellhead operation control valve according to the present invention in the fully open position is shown. Figure 3 It shows Figure 1 The diagram shows a three-dimensional structure of the elastic pawl. Detailed Implementation

[0018] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0019] Figure 1 and Figure 2 The structure of a wellhead operation control valve 100 according to an embodiment of the present invention is shown. (In conjunction with...) Figure 1 and Figure 2As shown, the wellhead operation control valve 100 may include: an upper connector 1 for connection to a lift tubing; a lower connector 3 for connection to a tubing hook; a housing 2 connected between the upper connector 1 and the lower connector 3 to form an internal cavity, the internal cavity including an axially extending sliding section 21 and a limiting step 22 located below the sliding section 21; and a valve assembly, the valve assembly including a soluble ball 5 axially arranged in sequence within the internal cavity, an elastic pawl 6 abutting below the soluble ball 5, and a spring 7 elastically abutting between the elastic pawl 6 and the lower connector 3, the outer wall of the elastic pawl 6 slidingly engaging with the sliding section 21, and having at least one axial slit 63 formed on its outer wall. The wellhead operation control valve 100 has a closed position, a fully open position, and a semi-open position between the closed and fully open positions, such as... Figure 1 As shown, in the closed position, the spring 7 pushes the elastic pawl 6 upward, causing the upper part of the elastic pawl 6 to press the soluble ball 5 against the sealing slope 11 inside the upper connector 1, thereby isolating the pressure of the lower tubing. In the semi-open position, the soluble ball 5 and the elastic pawl 6, under the push of the first pressure, overcome the elastic force of the spring 7 and move downward, causing the soluble ball 5 to detach from the sealing slope 11, and the fluid flows through the slit 63 to establish a circulation channel. In the fully open position, the soluble ball 5 and the elastic pawl 6, under the action of a second pressure greater than the first pressure, move downward until the elastic pawl 6 abuts against the limiting step 22, and the outer wall of the elastic pawl 6 expands outward under the action of the second pressure to release the grip on the soluble ball 5, causing the soluble ball 5 to fall off.

[0020] After initial installation, the wellhead operation control valve 100 of this embodiment automatically enters the closed position under the pre-tightening force of the internal spring 7. The elastic pawl 6 presses the soluble ball 5 against the sealing slope 11 of the upper connector 1, forming a reliable internal blowout preventer, actively isolating downhole pressure and providing the primary safety barrier for operations. When well washing or well killing is required, a first pressure is applied to the tubing string. This pressure overcomes the spring force and pushes the soluble ball 5 and the elastic pawl 6 to move slightly downward together, causing the soluble ball 5 to detach from the sealing surface. The wellhead operation control valve 100 enters the semi-open position. At this time, the high-pressure fluid establishes a circulation channel through the slit 63 on the elastic pawl 6, allowing normal well washing and killing operations to be carried out, while the soluble ball 5 is still held tightly by the elastic pawl 6 to prevent it from falling off. After the cycle is completed, a higher second pressure is applied to push the component down until the elastic pawl 6 abuts against the limiting step 22 inside the housing 2. At this time, the outer wall of the elastic pawl 6 expands outward under the pressure, completely releasing the soluble ball 5, and the wellhead operation control valve 100 enters the fully open position. The fallen soluble ball 5 dissolves on its own, and the channel inside the tubing is completely unobstructed, allowing for subsequent wireline operations or tubing retrieval without hindrance.

[0021] The wellhead operation control valve 100 of this utility model, through an integrated mechanical valve body structure, completely eliminates the complex process of traditional well workover operations that requires reconnecting a long hydraulic control line from the tubing to the drilling platform. This design fundamentally solves three major industry problems: difficulty in crossing hydraulic control lines, susceptibility to crushing damage, and interference with blowout preventer (BOP) assembly pressure testing. Internally, the wellhead operation control valve 100, through the cooperation of a soluble ball 5, an elastic pawl 6, and a spring 7, sequentially achieves three core functions—isolation pressure, circulation establishment, and full opening—simply by pressurizing the tubing string. Operation is extremely simple and reliable, significantly improving the timeliness and safety of offshore well workover operations.

[0022] In such Figure 1 and Figure 3 In the preferred embodiment shown, the resilient pawl 6 may include an annular base 61 for sealing abutment against the soluble ball 5 and at least two resilient flaps 62 extending downward from the annular base 61, with at least one axial slit 63 formed between adjacent resilient flaps 62. The annular base 61 provides a basis for stable contact with the soluble ball 5 and transmission of axial force, while the individual resilient flaps 62 are separated by the axial slit 63, giving the resilient pawl 6 the necessary radial elastic deformation capability. This structure is key to enabling its reliable expansion at the limiting step 22, thereby releasing the soluble ball 5.

[0023] Preferably, the annular base 61 can be constructed as an arc-shaped groove or ball-and-socket structure that seals against the soluble ball 5. These shapes and structures can form a good fit and support with the spherical surface of the soluble ball 5, increasing the contact area, making the force transmission more uniform, and more stably holding the soluble ball 5 in the closed position, ensuring that an effective line seal or surface seal is formed between it and the sealing slope 11 of the upper connector 1, thus improving the reliability of the initial sealing pressure.

[0024] Furthermore, such as Figure 3 As shown, the elastic flap 62 may include a sliding engagement section 65 located at its bottom for abutting against the limiting step 22, and a connecting section 64 connecting the sliding engagement section 65 and the annular base 61. The outer diameter of the sliding engagement section 65 is the same as the inner diameter of the sliding section 21, while the outer diameter of the connecting section 64 is smaller than the inner diameter of the sliding section 21. The sliding engagement section 65 ensures smooth and stable axial movement of the elastic pawl 6 within the sliding section 21. The reduced outer diameter of the connecting section 64 creates a pre-set expansion space. When the elastic pawl 6 descends to the limiting step 22, the connecting section 64 is positioned precisely above the step 22. Due to its smaller diameter, it can immediately and smoothly expand outward under internal pressure, thereby quickly and reliably releasing the constraint on the soluble ball 5, resulting in precise and efficient operation.

[0025] Preferably, the elastic pawl 6 can be made of spring steel, stainless steel, or beryllium bronze. Materials such as spring steel, stainless steel, or beryllium bronze combine high strength, high elasticity, and good wear resistance, ensuring that the elastic pawl 6 can withstand repeated compression, sliding, and expansion deformation in harsh downhole environments without plastic deformation or breakage, thus guaranteeing the reusability and long-term reliability of the wellhead operation control valve 100.

[0026] Preferably, the soluble ball 5 is made of a material that can dissolve in the wellbore working fluid. When the soluble ball 5 falls after completing its sealing and circulation functions, it will dissolve and disappear in the wellbore fluid without requiring time-consuming and risky retrieval operations. This greatly simplifies the operation process and prevents the fallen ball from becoming a new downhole hazard. Preferably, the material of the soluble ball 5 can be a magnesium alloy, an aluminum alloy, or a soluble polymer. Magnesium alloys, aluminum alloys, or certain soluble polymers have predictable and reliable dissolution properties under downhole temperature, pressure, and fluid chemistry environments.

[0027] In such Figure 1 and Figure 2 In the preferred embodiment shown, the wellhead operation control valve 100 may further include an anti-backlash pin 4, which is connected to the connection between the upper connector 1 and the housing 2, and to the connection between the housing 2 and the lower connector 3. In complex working conditions that may be encountered during offshore well workover (such as tubing reversal for unsticking), the anti-backlash pin 4 effectively prevents the threaded connections between the upper connector 1, housing 2, and lower connector 3 from loosening due to reversing torque. This greatly enhances the integrity of the overall tool structure, prevents accidental disintegration downhole, and improves operational safety.

[0028] In such Figure 1 In the preferred embodiment shown, the sealing slope inside the upper connector 1 can be a conical surface. The conical-spherical sealing method is a proven and reliable sealing method with high contact stress, good sealing effect, and a certain tolerance for machining and assembly errors. This further ensures that the tool can withstand high pressure and achieve effective sealing in the closed position, meeting the requirements of internal blowout preventers.

[0029] Furthermore, the lower connector 3 may have a standard API thread for connecting to a tubing hanger. This standard API thread can be directly connected to standard tubing hangers widely used on offshore platforms without any modification to existing wellhead equipment, greatly facilitating the field application and promotion of the tool and lowering the barrier to entry.

[0030] It should be noted that, unless otherwise stated, the technical or scientific terms used in this utility model shall have the ordinary meaning as understood by those skilled in the art to which this utility model pertains.

[0031] In the description of this utility model, it should be understood that the terms "axial", "upper", "lower", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0032] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model, and they should all be covered within the scope of the claims and specification of this utility model. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This utility model is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A wellhead operation control valve, characterized in that, include: Upper connector (1) is used to connect to the lifting oil pipe; The lower connector (3) is used for connection with the oil pipe. A housing (2), connected between the upper connector (1) and the lower connector (3), forms an internal cavity, the internal cavity including an axially extending sliding section (21) and a limiting step (22) located below the sliding section (21); and The valve assembly includes a soluble ball (5) arranged axially in the internal cavity, an elastic pawl (6) abutting below the soluble ball (5), and a spring (7) elastically abutting between the elastic pawl (6) and the lower connector. The outer wall of the elastic pawl (6) slides with the sliding section (21), and at least one axial slit (63) is formed on its outer wall. The wellhead operation control valve has a closed position, a fully open position, and a semi-open position between the closed position and the fully open position. In the closed position, the spring (7) pushes the elastic pawl (6) upward, so that the upper part of the elastic pawl (6) presses the soluble ball (5) against the sealing slope (11) inside the upper connector (1) to isolate the lower tubing pressure. In the semi-open position, the soluble ball (5) and the elastic pawl (6) together overcome the elastic force of the spring and move downward under the push of the first pressure, so that the soluble ball (5) is separated from the sealing slope, and the fluid flows through the cut (63) to establish a circulation channel. At the fully open position, the soluble ball (5) and the elastic pawl (6) move down under the action of a second pressure greater than the first pressure until the elastic pawl (6) abuts against the limiting step (22), and the outer wall of the elastic pawl (6) expands outward under the action of the second pressure to release the grip on the soluble ball (5), causing the soluble ball (5) to fall off.

2. The wellhead operation control valve according to claim 1, characterized in that, The elastic pawl (6) includes an annular base (61) for sealing abutment against the soluble ball (5) and at least two elastic flaps (62) extending downward from the annular base (61), wherein the at least one axial slit (63) is formed between adjacent elastic flaps (62).

3. The wellhead operation control valve according to claim 2, characterized in that, The annular base (61) is constructed as an arc-shaped groove or ball-and-socket structure that seals against the soluble ball (5).

4. The wellhead operation control valve according to claim 2, characterized in that, The elastic flap (62) includes a sliding engagement section (65) located at its bottom for abutting against the limiting step and a connecting section (64) connecting the sliding engagement section (65) and the annular base (61). The outer diameter of the sliding engagement section (65) is the same as the inner diameter of the sliding section (21), and the outer diameter of the connecting section (64) is smaller than the inner diameter of the sliding section (21).

5. The wellhead operation control valve according to claim 4, characterized in that, The elastic pawl (6) is made of spring steel, stainless steel or beryllium bronze.

6. The wellhead operation control valve according to any one of claims 1 to 5, characterized in that, The soluble ball (5) is made of a material that can dissolve in the wellbore working fluid.

7. The wellhead operation control valve according to claim 6, characterized in that, The soluble sphere (5) is made of magnesium alloy, aluminum alloy or soluble polymer.

8. The wellhead operation control valve according to any one of claims 1 to 5, characterized in that, The wellhead operation control valve also includes an anti-backlash pin (4), which is connected to the connection between the upper connector (1) and the housing (2), and the connection between the housing (2) and the lower connector (3).

9. The wellhead operation control valve according to any one of claims 1 to 5, characterized in that, The sealing slope (11) inside the upper connector (1) is a conical surface.

10. The wellhead operation control valve according to any one of claims 1 to 5, characterized in that, The lower connector (3) has a standard API thread for connecting the tubing hanger.

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