A downhole safety valve

Abstract

The present invention discloses a downhole safety valve, comprising: a main body, a piston assembly and a valve plate, a sealing member, and a butt joint, wherein a hydraulic cavity is formed between the upper end of the piston assembly and the main body, and the lower end of the piston assembly cooperates with the valve plate, a liquid infusion channel connected to the hydraulic cavity is arranged on the main body, the liquid infusion channel is connected to the end face of the main body, the sealing member is installed in the liquid infusion channel from the end face side of the main body, a radial channel connected to the liquid infusion channel is also arranged on the main body, an inner boss is arranged in the main body above the hydraulic cavity, a liquid outlet channel connected to the radial channel is arranged on the inner boss, and the butt joint is sealed and installed in the liquid outlet channel. A control pipeline connected to the butt joint is arranged inside the pipe column, and a clip for fixing the control pipeline does not need to be installed on the outer wall of the pipe column. When the well is inspected and repaired, the butt joint is unloaded from the safety valve through the control pipeline, and the blowout prevention pipe column operation can be easily performed, which can greatly improve the pipe column lifting speed and avoid safety hazards.

Description

Technical Field

[0001] The invention relates to the technical field of oil and gas production tools in oil fields, in particular to a downhole safety valve. Background Art

[0002] Downhole safety valves are installed in oil and gas wells. When a fire occurs in the production facilities, a pipeline ruptures, or an irresistible natural disaster (such as an earthquake, ice, or a strong typhoon) occurs, the downhole production channel can be closed in time to prevent oil and gas leakage from causing environmental pollution and other safety accidents. Figure 1 As shown in the figure, the general working principle of the downhole safety valve is: add hydraulic oil from the ground, the high-pressure liquid enters the hydraulic chamber e through the control pipeline a, pushes the piston b downward, compresses the spring c, and the piston b pushes the valve plate d to open the downhole safety valve; maintain the ground control pressure, the downhole safety valve remains in the open state; release the ground control pressure, the valve plate d is reset under the action of the torsion spring at its rotating shaft, and the downhole safety valve is closed.

[0003] like Figure 1 As shown, currently, the downhole safety valve control pipeline a is designed to be outside the oil pipe and connected to the pipe wall outside the downhole safety valve. During the high-pressure well repair process, the control pipeline is also clamped on the outer wall of the oil pipe by the pipeline clamp. During the high-pressure oil, gas and water well repair process, the installation position of the control pipeline a will bring huge workload and construction risks to the pipe string for blowout prevention operations. Summary of the invention

[0004] In view of the problems existing in the prior art, the purpose of the present invention is to provide a downhole safety valve, which can well solve the technical problem of lifting the pipe string in blowout prevention operations through the connection between the downhole safety valve and the control pipeline.

[0005] To achieve the above object, the technical solution of the present invention is as follows:

[0006] A downhole safety valve comprises: a main body, a piston assembly and a valve plate, a sealing member and a butt joint, wherein a hydraulic cavity is formed between the upper end of the piston assembly and the main body, and the lower end of the piston assembly cooperates with the valve plate; a liquid infusion channel connected to the hydraulic cavity is arranged on the main body, the liquid infusion channel is connected to the end surface of the main body, the sealing member is installed in the liquid infusion channel from the end surface side of the main body, a radial channel connected to the liquid infusion channel is also arranged on the main body, an inner boss is arranged in the main body above the hydraulic cavity, a liquid outlet channel connected to the radial channel is arranged on the inner boss, and the butt joint is seal-mounted in the liquid outlet channel.

[0007] Furthermore, the downhole safety valve also includes a sleeve, the liquid outlet channel passes through the inner boss, the liquid outlet channel includes a first hole section located at the upper part and a second hole section located at the lower part, the inner diameter of the first hole section is smaller than the inner diameter of the second hole section, the second hole section is connected to the radial channel, the sleeve is installed in the second hole section, the outer wall of the sleeve is fitted with the inner wall of the second hole section, and shear pins for limiting the sleeve are also installed in the second hole section, so that the sleeve closes the radial channel.

[0008] Furthermore, first sealing grooves are provided on both upper and lower sides of the inner wall of the second hole section connected to the radial channel. The first sealing groove is located at the matching position between the second hole section and the sliding sleeve, and a first sealing ring is installed in the first sealing groove.

[0009] Further, the docking device includes: a first column section matching with the first hole section, a sealing sleeve mounted on the lower part of the first column section, and a first limiting shear pin; the outer diameter of the sealing sleeve matches with the second hole section; the sealing sleeve is provided with a radial first positioning hole, and the first limiting shear pin passes through the first positioning hole to fix the sealing sleeve to the first column section; the outer wall of the first column section is provided with a retaining ring groove and a sealing ring groove, the distance between the upper end surface of the sealing sleeve and the retaining ring groove is greater than the sum of the axial lengths of the first hole section and the sliding sleeve, the sealing ring groove is provided between the retaining ring groove and the sealing sleeve, the distance between the retaining ring groove and the sealing ring groove is less than the axial length of the first hole section, a retaining ring is installed in the retaining ring groove, and a sealing ring is installed in the sealing ring groove.

[0010] Furthermore, the docking device also includes an annular limit sleeve and a second limit shear pin, the outer diameter of the limit sleeve is larger than the inner diameter of the second hole segment, the limit sleeve is provided with a radial second positioning hole, the second limit shear pin passes through the second positioning hole to fix the limit sleeve to the lower end of the first column segment, and the distance from the upper end surface of the limit sleeve to the retaining ring groove is greater than or equal to the thickness of the inner boss.

[0011] Furthermore, a second sealing groove is provided on both the inner wall and the outer wall of the sealing sleeve, and a second sealing ring is installed in the second sealing groove.

[0012] The downhole safety valve of the present invention seals the liquid outlet channel through a docking device. When the safety valve needs to be opened, the seal is opened to input hydraulic oil into the hydraulic cavity through the liquid infusion channel. After the safety valve is opened, the liquid infusion channel is sealed with a seal. When a safety accident occurs, the docking device is removed to release the pressure in the hydraulic cavity so that the valve plate can be reset and covered to the piston cylinder port of the piston assembly under the action of its torsion spring. The docking device is installed inside the safety valve body, and accordingly, the control pipeline connected to the docking device is arranged inside the pipe column. There is no need to install a clip for fixing the control pipeline on the outer wall of the pipe column. When the well is inspected and repaired, the docking device is removed from the safety valve through the control pipeline, so that the operation of lifting the pipe column for blowout prevention can be carried out very conveniently. At the same time, the lifting speed of the pipe for blowout prevention operation can be greatly improved, avoiding safety hazards. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a structural schematic diagram of the connection between the hydraulic control pipeline and the downhole safety valve in the background technology;

[0014] Figure 2 A schematic diagram of the structure of a downhole safety valve provided in Example 1 of the present invention;

[0015] Figure 3 for Figure 2 A partial enlarged schematic diagram of

[0016] Figure 4 It is a structural schematic diagram of the docking device in Example 1 of the present invention;

[0017] Figure 5 This is a schematic diagram of the docking installation of the docking device and the downhole safety valve in Example 1 of the present invention;

[0018] Figure 6 This is a schematic structural diagram of the sealing state of a portion of a docking device and a downhole safety valve in Embodiment 1 of the present invention;

[0019] Figure 7 This is a schematic diagram of the butt joint and the downhole safety valve being disconnected in Embodiment 1 of the present invention;

[0020] Figure 8 A schematic diagram of the structure of a downhole safety valve provided in Example 2 of the present invention;

[0021] In the figure:

[0022] 1. Seal; 2. Main body; 21. Infusion channel; 22. Inner boss; 23. Radial channel; 24. Liquid outlet channel; 241. First hole section; 242. Second hole section; 243. First sealing ring; 3. Sleeve; 4. Shear pin; 5. Piston assembly; 51. Piston cylinder; 6. Spring; 7. Valve plate; 8. Hydraulic chamber; 9. Butt connector; 91. First column section; 92. Retaining ring; 93. Sealing ring; 94. Sealing sleeve; 941. Second sealing ring; 95. First limit shear pin; 96. Limit sleeve; 97. Second limit shear pin; 98. Connecting thread; 10. Connecting joint. DETAILED DESCRIPTION

[0023] In order to clearly illustrate the design concept of the present invention, the present invention is described below in conjunction with examples.

[0024] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solution of the present invention is clearly and completely described below in conjunction with the drawings in the examples of the present invention. Obviously, the described examples are only part of the examples of the present invention, not all of the examples. Based on the examples in the present invention, all other implementation methods obtained by ordinary technicians in the field without making creative work should fall within the scope of protection of the present invention.

[0025] In the description of the present embodiment, the terms "upper", "lower", "left", "right", etc., indicating directions or positional relationships are based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used to distinguish similar objects, and cannot be understood as a specific order or sequence, and it should be understood that such usage can be interchangeable under appropriate circumstances.

[0026] The present invention provides a downhole safety valve, comprising: a main body, a piston assembly and a valve plate, a sealing member and a docking device, wherein a hydraulic cavity is formed between the upper end of the piston assembly and the main body, and the lower end of the piston assembly cooperates with the valve plate; a liquid infusion channel connected to the hydraulic cavity is arranged on the main body, the liquid infusion channel is connected to the end surface of the main body, the sealing member is installed in the liquid infusion channel from the end surface side of the main body, a radial channel connected to the liquid infusion channel is also arranged on the main body, an inner boss is arranged in the main body above the hydraulic cavity, a liquid outlet channel connected to the radial channel is arranged on the inner boss, and the docking device is seal-installed in the liquid outlet channel.

[0027] The downhole safety valve of the present invention seals the liquid outlet channel through a docking device. When the safety valve needs to be opened, the seal is opened to input hydraulic oil into the hydraulic cavity through the liquid infusion channel. After the safety valve is opened, the liquid infusion channel is sealed with a seal. When a safety accident occurs, the docking device is removed to release the pressure in the hydraulic cavity so that the valve plate can be reset and covered to the piston cylinder port of the piston assembly under the action of its torsion spring. The docking device is installed inside the safety valve body, and accordingly, the control pipeline connected to the docking device is arranged inside the pipe column. There is no need to install a clip for fixing the control pipeline on the outer wall of the pipe column. When the well is inspected and repaired, the docking device is removed from the safety valve through the control pipeline, so that the operation of lifting the pipe column for blowout prevention can be carried out very conveniently. At the same time, the lifting speed of the pipe for blowout prevention operation can be greatly improved, and safety hazards can be avoided.

[0028] In order to more clearly explain the technical solution in the present invention, the present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments. In the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other.

[0029] Example 1

[0030] like Figure 2-7 As shown, a first embodiment of the downhole safety valve of the present invention is provided, the downhole safety valve comprises: a main body 2, a piston assembly 5 and a valve plate 7, a sealing member 1, and a butt joint 9, all of which are installed in the main body 2; in this embodiment, as shown Figure 2 As shown, the main body 2 is a shell located outside the downhole safety valve, the piston assembly 5 includes a piston cylinder 51, a spring 6 and a sealing ring installed in a sealing groove above the piston cylinder 51, and the valve plate 7 is fixed to the inside of the main body 2 through a rotating shaft. A torsion spring is installed on the rotating shaft, and the valve plate 7 is driven to reset by the torsion spring. The sealing member 1 is a threaded plug.

[0031] A hydraulic chamber 8 is formed between the upper end of the piston cylinder 51 of the piston assembly 5 and the main body 2, and the lower end of the piston cylinder 51 of the piston assembly 5 cooperates with the valve plate 7; an infusion channel 21 connected to the hydraulic chamber 8 is provided on the main body 2, and the infusion channel 21 is connected to the end face of the main body 2, and a plug is installed in the infusion channel 21 from the end face side of the main body. Obviously, an internal thread that cooperates with the plug is provided at the port of the infusion channel 21, and a radial channel 23 connected to the infusion channel 21 is also provided on the main body 2, an inner boss 22 is provided in the main body 2 above the hydraulic chamber 8, and a liquid outlet channel 24 connected to the radial channel 23 is provided on the inner boss 22, and the docking device 9 is sealed and installed in the liquid outlet channel 24.

[0032] Preferably, if Figure 2 , 5As shown in Figures 6 and 7, the liquid outlet channel 24 passes through the inner boss 22. The liquid outlet channel 24 includes a first hole section 241 located at the upper part and a second hole section 242 located at the lower part. The inner diameter of the first hole section 241 is smaller than the inner diameter of the second hole section 242. The second hole section 242 is connected to the radial channel 23. The sleeve 3 of the downhole safety valve is installed in the second hole section 242. The outer wall of the sleeve 3 fits the inner wall of the second hole section 242. The shear pins 4 for limiting the position of the sleeve 3 are also installed in the second hole section 242. The shear pins 4 are used to limit the position of the sleeve 3. The sleeve 3 closes the radial channel 23 through the limiting of the shear pins 4. Figure 3 As shown, first sealing grooves are provided on both upper and lower sides of the inner wall of the second hole section 242 communicating with the radial channel 23. The first sealing groove is located at the matching position of the second hole section 242 and the sliding sleeve 3, and the first sealing ring 243 is installed in the first sealing groove. In this way, even if the docking device 9 has not been docked and installed in the liquid outlet channel 24, the sliding sleeve 3 will have a sealing effect on the liquid outlet channel 24, thereby preventing the hydraulic oil from leaking out.

[0033] like Figure 4 As shown, the docking device 9 includes a first column section 91 that cooperates with the first hole section 241, and a sealing sleeve 94 that is mounted on the lower part of the first column section 91, and the outer diameter of the sealing sleeve 94 cooperates with the second hole section 242; the sealing sleeve 94 is provided with a radial first positioning hole, and the first limiting shear nail 95 passes through the first positioning hole to fix the sealing sleeve 94 to the first column section 91; the outer wall of the first column section 91 is provided with a retaining ring groove and a sealing ring groove, and the distance between the upper end surface of the sealing sleeve 94 and the retaining ring groove is greater than the sum of the axial lengths of the first hole section 241 and the sliding sleeve 3, ensuring that the retaining ring groove can extend out of the first hole section 241, and a retaining ring 92 is installed in the retaining ring groove; the sealing ring groove is provided between the retaining ring groove and the sealing sleeve, and the distance between the retaining ring groove and the sealing ring groove is less than the axial length of the first hole section 241, ensuring that the sealing ring 93 installed in the sealing ring groove can pop out from the first hole section 241. The docking device 9 also includes an annular limiting sleeve 96 and a second limiting shearing nail 97. The outer diameter of the limiting sleeve 96 is greater than the inner diameter of the second hole section 242. The limiting sleeve 96 is provided with a radial second positioning hole. The second limiting shearing nail 97 passes through the second positioning hole to fix the limiting sleeve 96 to the lower end of the first column section 91. The distance from the upper end surface of the limiting sleeve 96 to the snap ring groove is greater than or equal to the thickness of the inner boss 22, ensuring that the docking device 9 is installed from the lower end of the inner boss 22 to the liquid outlet channel 24. When the docking device 9 is sealed with the liquid outlet channel, the snap ring groove can expose the upper end surface of the inner boss 22, and the snap ring 92 is removed from the snap ring groove. In order to facilitate the fixing of the limiting sleeve 96, in this embodiment, the inner diameter of the limiting sleeve 96 matches the outer diameter of the first column section 91.

[0034] It is understandable that in order to install the first limiting shear nail 95 and the second limiting shear nail 97 on the first column section 91, an annular groove is set at the corresponding position of the first column section 91 to facilitate the installation and fixation of the first limiting shear nail 95 and the second limiting shear nail 97.

[0035] In this embodiment, the inner wall and the outer wall of the sealing sleeve 94 are both provided with a second sealing groove, and the second sealing ring 941 is installed in the second sealing groove to ensure that when the docking connector 9 is sealed and installed in the liquid outlet channel 24, the sealing sleeve 94 is effectively sealed with the first column section 91 and the inner wall of the second hole section 242.

[0036] In this embodiment, a connecting thread 98 is provided at the upper end surface of the first column section 91 for connecting with the connecting joint 10 of the control pipeline so as to pull up the docking device 9 for docking and pull the docking device 9 out of the liquid outlet channel 24.

[0037] like Figure 5-7 As shown, it reflects the use method and working principle of the downhole safety valve in this embodiment:

[0038] Downhole safety valve into the well process: Figure 5 As shown, after the control pipeline is connected to the docking device 9 through the connecting joint 10, it is suspended on the liquid outlet channel 24 that penetrates the inner boss 22 in the downhole safety valve. The downhole safety valve is in a sealed state. At this time, the clamping ring 92 and the sealing ring 93 are respectively inserted into the clamping ring groove and the sealing ring groove provided on the first column section;

[0039] The docking of the docking device 9 and the downhole safety valve and the opening process of the downhole safety valve: After the oil pipe string is lowered, the control pipeline is salvaged by using a fishing tool using a steel wire operation or other operations and a certain pulling force is applied to make the docking device 9 connected to the lower end of the control pipeline dock with the liquid outlet channel 24 of the downhole safety valve. Figure 6 As shown, during the docking process, the sleeve 3 moves upward, the docking device 9 seals the radial channel 23, and then the first column section 91 is lifted up through the control pipeline, and the docking device 9 is fixed through the first limit shear nail 95. At this time, the clamping ring 92 is disengaged from the clamping ring groove, the wellhead and downhole control pipeline control system is connected and the wellhead is installed and put into production, the plug is opened, and hydraulic oil is input into the hydraulic chamber 8 through the infusion channel 21. After the downhole safety valve is opened, the infusion channel 21 is closed again by the plug;

[0040] The process of closing the downhole safety valve and lifting the pipe string: dismantle the wellhead, increase the force to lift the control pipeline, so that the second limit shear nail on the docking device 9 is broken, the limit sleeve 96 falls off from the first column section 91, and the first column section 91 escapes from the liquid outlet channel 24, completing the pressure relief of the hydraulic chamber 8, and the downhole safety valve closes automatically. In this way, since there is no influence of the fixed control pipeline clip, it is very convenient and quick to lift the downhole pipe string and supporting tools during the blowout prevention operation, which greatly reduces the construction difficulty and safety risks and improves work efficiency.

[0041] It should be noted that, in the above process, the docking device 9 can achieve sealing with the downhole safety valve to ensure the opening of the downhole safety valve, and can also relieve pressure in the hydraulic chamber 8 to achieve the closing of the downhole safety valve.

[0042] Example 2

[0043] like Figure 8 As shown, this embodiment is an improvement on the structure of the downhole safety valve based on the embodiment 1, and the improvement lies in that the liquid outlet channel 24 is connected with the radial channel 23, but does not penetrate the inner boss 22. Before lowering the pipe string into the well, the sealing of the docking device and the liquid outlet channel must be completed. The docking device here can be a screw connected to the control pipeline, a connecting joint connected to the control pipeline, etc. When the downhole safety valve needs to be closed, the docking device is also removed from the liquid outlet channel 24, and the hydraulic oil also flows into the interior of the main body 2 along the liquid outlet channel 24 to complete the pressure relief of the hydraulic chamber 8, and the downhole safety valve closes automatically. In this way, since there is no influence of the fixed control pipeline clip, it is very convenient and quick to pull out the downhole pipe string and the supporting tools in the blowout prevention operation, which greatly reduces the construction difficulty and safety risks and improves work efficiency.

[0044] It should be noted that the “upper” and “lower” mentioned in the above implementation refer to the relative directions of the downhole safety valve when in use.

[0045] Finally, it is understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present invention, but the present invention is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the principles and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A downhole safety valve, characterized in that: include: A main body (2), a piston assembly (5) and a valve plate (7) all mounted in the main body (2), a sealing member (1), and a docking device (9); a hydraulic chamber (8) is formed between the upper end of the piston assembly (5) and the main body (2), and the lower end of the piston assembly (5) cooperates with the valve plate (7); an infusion channel (21) communicating with the hydraulic chamber (8) is provided on the main body (2), the infusion channel (21) is connected to the end surface of the main body (2), the sealing member (1) is installed in the infusion channel (21) from the end surface side of the main body, and a radial channel (23) communicating with the infusion channel (21) is further provided on the main body (2); an inner boss (22) is provided in the main body (2) above the hydraulic chamber (8), and a flange (23) communicating with the radial channel (23) is provided on the inner boss (22). 3) a liquid outlet passage (24) connected to the inner boss (22), the butt joint (9) being sealingly installed in the liquid outlet passage (24); a control pipeline being connected to the butt joint (9); the downhole safety valve further comprising a sleeve (3), the liquid outlet passage (24) passing through the inner boss (22), the liquid outlet passage (24) comprising a first hole section (241) located at the upper part and a second hole section (242) located at the lower part, the sleeve (3) being installed in the second hole section (242), the outer wall of the sleeve (3) being in contact with the inner wall of the second hole section (242); the butt joint (9) comprising a first column section (91) matching with the first hole section (241), and a sealing sleeve (94) being sleeved on the lower part of the first column section (91), the outer diameter of the sealing sleeve (94) matching with the second hole section (242).

2. The downhole safety valve according to claim 1, characterized in that: The inner diameter of the first hole section (241) is smaller than the inner diameter of the second hole section (242); the second hole section (242) is in communication with the radial channel (23); and a shear pin (4) for limiting the position of the sliding sleeve (3) is also installed in the second hole section (242), so that the sliding sleeve (3) closes the radial channel (23).

3. The downhole safety valve according to claim 2, characterized in that: First sealing grooves are provided on both upper and lower sides of the inner wall of the second hole section (242) communicating with the radial channel (23); the first sealing groove is located at the matching position between the second hole section (242) and the sliding sleeve (3); and a first sealing ring (243) is installed in the first sealing groove.

4. The downhole safety valve according to claim 2, characterized in that: The docking device (9) comprises: a first limiting shear pin (95); a first radial positioning hole is provided on the sealing sleeve (94), and the first limiting shear pin (95) passes through the first positioning hole to fix the sealing sleeve (94) to the first column section (91); a retaining ring groove and a sealing ring groove are provided on the outer wall of the first column section (91), the distance between the upper end surface of the sealing sleeve (94) and the retaining ring groove is greater than the sum of the axial lengths of the first hole section (241) and the sliding sleeve (3), the sealing ring groove is provided between the retaining ring groove and the sealing sleeve (94), the distance between the retaining ring groove and the sealing ring groove is less than the axial length of the first hole section (241), a retaining ring (92) is installed in the retaining ring groove, and a sealing ring (93) is installed in the sealing ring groove.

5. The downhole safety valve according to claim 4, characterized in that: The docking device (9) further comprises an annular limiting sleeve (96) and a second limiting shearing nail (97); the outer diameter of the limiting sleeve (96) is greater than the inner diameter of the second hole section (242); the limiting sleeve (96) is provided with a radial second positioning hole; the second limiting shearing nail (97) passes through the second positioning hole to fix the limiting sleeve (96) to the lower end of the first column section (91); and the distance from the upper end surface of the limiting sleeve (96) to the retaining ring groove is greater than or equal to the thickness of the inner boss (22).

6. The downhole safety valve according to claim 4 or 5, characterized in that: The inner wall and the outer wall of the sealing sleeve (94) are both provided with a second sealing groove, and the second sealing ring (941) is installed in the second sealing groove.

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