Blocking tool for non-releasing valve replacement under pressure of wellhead gas production tree

Abstract

The invention relates to the technical field of Christmas tree valve replacement maintenance, and discloses a plugging tool for wellhead Christmas tree non-releasing under-pressure valve replacement, which comprises a shell, a limiting sleeve, a second cylinder barrel, a rubber barrel assembly, a guide shoe, a mandrel, a spring, a first cylinder barrel and a piston which are coaxially arranged. When the plugging tool is fed into a pipeline at the front end of a valve, the rubber sleeve assembly can be axially compressed and radially expanded directly through hydraulic pressurization during use, so that when the rubber sleeve assembly and the inner wall of the pipeline are expanded and sealed, pressurization is stopped and a feeding and pressurizing device is subsequently disassembled, a pressure maintaining effect can be achieved under the action of the spring and the elastic force of the rubber sleeve assembly; after the valve is replaced, the rigid piece can be directly used for pushing the core shaft to realize pressure relief and unblocking; the blocking tool can achieve valve replacement operation under pressure, has the advantages of being reliable in sealing and easy to unblock, and is relatively simple in structure and convenient to operate.

Description

Technical Field

[0001] The invention relates to the technical field of valve replacement and maintenance of gas production trees, and in particular to a plugging tool for pressure-free valve replacement of a wellhead gas production tree. Background Art

[0002] The gas tree refers to the general term for the part installed above the pipe head of the wellhead device. It is mainly composed of the wellhead four-way and the main control valve (main gate, pipeline gate, needle valve, pressure measuring gate, casing gate, etc.). It is the main device for opening and closing wells, adjusting pressure, measuring pressure with a pressure gauge, and measuring wellhead pressure.

[0003] Since the wellhead device directly controls the collection of natural gas in the well under high pressure, it is in working condition once installed, so it is extremely difficult to repair and replace the main control valve. The traditional replacement method is to first use well killing fluid to kill the construction well, and then replace the wellhead main control valve after the well killing is stable. It has problems such as long construction period, many equipment, large workload, many cooperative construction units, many participants, serious environmental pollution caused by the discharge of well killing fluid, and high construction cost. At the same time, this traditional method will also cause secondary damage to the bottom of the well, especially for old wells in the middle and late stages of production. Due to the low formation energy, it is difficult to restore the original production after killing the well. Some wells may be killed and lose production capacity and become abandoned wells.

[0004] In order to overcome the defects of traditional replacement methods, technicians in this field have been committed to studying the replacement form of valve replacement under pressure. At present, we use the method of cava positioning and card point to replace valves or repair. This method is to install the cava at a fixed point on the inner wall of the pipe head at the front end of the valve to be replaced for sealing, and disconnect the valve to be replaced from the gas tree pipeline to facilitate its replacement; but in actual application, because the pipe head flow channel is corroded by acidic media due to long-term work, its inner wall is often uneven, and the selection of the card point position is difficult. After installation, the connection and sealing reliability of the cava and the inner wall are poor, and there are safety hazards in the subsequent valve replacement operation. In this method, it is also difficult to disassemble and remove the cava after the valve replacement operation. There are also various forms of devices for pipe head blocking in other fields in the prior art, but these devices are difficult to meet the requirements of reliable sealing, easy unsealing, and convenient operation when used for valve replacement under pressure on gas trees. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a plugging tool for pressure-changing valves at a wellhead gas tree without losing the hand. When used for replacing valve parts of a gas tree, the tool does not require wellbore pressure operation and can achieve pressure-changing valves. It has the advantages of reliable sealing and easy unsealing, and has a relatively simple structure and is easy to operate.

[0006] The objective of the present invention is achieved through the following technical solutions: A plugging tool for pressure valve replacement at a wellhead gas tree without losing the hand, comprising a coaxially arranged housing, a limit sleeve, a second cylinder, a rubber cylinder assembly, a guide shoe, a core shaft, a spring, a first cylinder, and a piston; The shell is a hollow cylindrical structure with two ends open, the limit sleeve is fixedly arranged in the middle of the shell, one end of the second cylinder is slidably arranged in one end of the shell, the other end of the second cylinder is fixedly connected to the guide shoe, the rubber cylinder assembly is sleeved outside the second cylinder, and the two ends of the rubber cylinder assembly are respectively abutted against the end of the shell and the end of the guide shoe; The end of the limit sleeve away from the guide shoe is processed with a first core hole and a first pressure transmission hole, and the inside of the limit sleeve is processed with a small diameter hole and a large diameter hole in sequence along the axis toward the other end, and the two ends of the first pressure transmission hole are respectively connected with the small diameter hole and the inner cavity of the end of the shell away from the second cylinder, and the connection part of the small diameter hole and the large diameter hole forms a conical sealing platform; One end of the first cylinder is fixedly inserted into the end of the large diameter hole away from the small diameter hole and is processed with a second core hole and a second pressure transmission hole, the other end of the first cylinder is fixedly connected to the piston, and the two ends of the second pressure transmission hole are respectively connected to the large diameter hole and the inner cavity of the first cylinder; The outer wall of the first cylinder is slidably fitted with the end of the second cylinder away from the guide shoe, the piston is slidably fitted with the inner wall of the second cylinder, the piston divides the inner cavity of the second cylinder into a rod cavity and a rodless cavity, the rod cavity is arranged on the side of the piston close to the first cylinder, a third pressure transmission hole is provided on the side wall of the first cylinder, the two ends of the third pressure transmission hole are respectively connected with the rod cavity and the inner cavity of the first cylinder, the guide shoe is provided with a flow channel hole, the two ends of the flow channel hole are respectively connected with the rodless cavity and the side of the guide shoe away from the second cylinder; A conical block is fixedly sleeved on the core shaft, one end of the core shaft is slidably disposed in the first core hole, the other end of the core shaft is slidably disposed in the second core hole, the conical block is disposed in the large diameter hole, and the conical block is adapted to the conical surface sealing platform; The spring is sleeved on the core shaft, and two ends of the spring are respectively in contact with the conical block and the end of the first cylinder.

[0007] Specifically, the rubber cylinder assembly includes a plurality of rubber cylinders, and the plurality of rubber cylinders are sequentially sleeved outside the second cylinder, and a spacer ring is provided between two adjacent rubber cylinders.

[0008] Specifically, sealing rings are arranged between the core shaft and the first core hole, between the core shaft and the second core hole, between the outer wall of the first cylinder and the end of the second cylinder away from the guide shoe, and between the piston and the inner wall of the second cylinder.

[0009] Specifically, an end of the shell away from the guide shoe is processed with an internal thread.

[0010] The beneficial effects of the present invention are: The plugging tool for pressure-changing valves in a wellhead gas production tree without losing the hand comprises a coaxially arranged shell, a limiting sleeve, a second cylinder, a rubber sleeve assembly, a guide shoe, a core shaft, a spring, a first cylinder and a piston. The limiting sleeve is fixedly inserted into the middle part of the shell, one end of the second cylinder is slidably arranged in one end of the shell, the other end of the second cylinder is fixedly connected to the guide shoe, the rubber sleeve assembly is sleeved outside the second cylinder, and the two ends of the rubber sleeve assembly are respectively abutted against the end of the shell and the end of the guide shoe; one end of the first cylinder is fixedly inserted into one end of the limiting sleeve, the barrel of the first cylinder is slidably inserted into one end of the second cylinder, the other end of the first cylinder is fixedly connected with a piston, and the piston is slidably arranged in the second cylinder; the core shaft is slidably arranged in the limiting sleeve, a conical block is sleeved on the core shaft, a conical surface limiting platform is arranged in the limiting sleeve, and the conical block is pressed against the conical surface sealing platform when the spring is used to provide elastic force; the limiting sleeve is provided with a first pressure transmission hole, and the first cylinder is provided with a second pressure transmission hole and a third pressure transmission hole. When the plugging tool for pressure-controlled valve replacement at the wellhead gas production tree is pressurized, the hydraulic oil can push open the conical block after entering through the first pressure transmission hole, and then enter the rod cavity of the second cylinder through the second pressure transmission hole, the inner cavity of the first cylinder, and the third pressure transmission hole in sequence, thereby driving the second cylinder and the guide shoe to move axially, so that the rubber cartridge assembly is axially compressed and radially expanded until the rubber cartridge assembly and the inner wall of the pipeline are tightly sealed; when the pressurization is stopped, the elastic force of the spring and the rubber cartridge assembly itself can maintain the pressure and maintain the reliability of the sealing; after the valve replacement is completed, the rigid part can be directly used to push the core shaft to achieve pressure relief and unsealing.

[0011] In general, the plugging tool for pressure valve replacement at the wellhead gas production tree can be used to achieve pressure valve replacement operation without losing the plugging tool. It has the advantages of reliable sealing and easy unsealing, and the structure is relatively simple and easy to use. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a schematic cross-sectional view of a plugging tool for pressure-assisted valve replacement at a wellhead gas tree without losing control of the present invention; Figure 2 for Figure 1 Enlarged view of section A in the middle; In the figure, 1-housing, 2-limiting sleeve, 3-core shaft, 4-first cylinder, 5-second cylinder, 6-piston, 7-guide shoe, 8-rubber cylinder, 9-spacer ring, 10-first pressure transmission hole, 11-small diameter hole, 12-large diameter hole, 13-second pressure transmission hole, 14-third pressure transmission hole, 15-flow channel hole, 16-conical block, 17-spring. DETAILED DESCRIPTION

[0013] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings, but the protection scope of the present invention is not limited to the following.

[0014] like Figure 1 , Figure 2 As shown, a plugging tool for pressure valve replacement in a wellhead gas production tree without losing the hand comprises a coaxially arranged housing 1, a limit sleeve 2, a second cylinder 5, a rubber cylinder assembly, a guide shoe 7, a core shaft 3, a spring 17, a first cylinder 4, and a piston 6.

[0015] The shell 1 is a hollow cylindrical structure with openings at both ends. The limit sleeve 2 is fixedly inserted into the middle part of the shell 1. One end of the second cylinder 5 is slidably arranged in one end of the shell 1. The other end of the second cylinder 5 is fixedly connected to the guide shoe 7. The rubber cartridge assembly is sleeved outside the second cylinder 5. The two ends of the rubber cartridge assembly are respectively abutted against the end of the shell 1 and the end of the guide shoe 7. When the second cylinder 5 slides toward the limit sleeve 2, it can drive the guide shoe 7 to slide axially, thereby causing the rubber cartridge assembly to be axially compressed and radially expanded.

[0016] The limiting sleeve 2 is a hollow columnar structure with one end open. The end of the limiting sleeve 2 away from the guide shoe 7 is a closed end, and a first core hole and a first pressure transmission hole 10 are processed at this end. A small diameter hole 11 and a large diameter hole 12 are processed in sequence along the axis toward the other end in the limiting sleeve 2 to form a hollow, and an opening is formed at the other end of the large diameter hole 12. The connecting part of the small diameter hole 11 and the large diameter hole 12 is processed to form a conical sealing platform, and the two ends of the aforementioned first pressure transmission hole 10 are respectively connected to the small diameter hole 11 and the inner cavity of the end of the shell 1 away from the second cylinder 5.

[0017] The first cylinder 4 is a cylindrical structure, one end of which is a closed end, which is fixedly inserted into the end of the large diameter hole 12 away from the small diameter hole 11 and processed with a second core hole and a second pressure transmission hole 13 at the end, and the other end of the first cylinder 4 is fixedly connected to the piston 6, and the two ends of the second pressure transmission hole 13 are respectively connected to the large diameter hole 12 and the inner cavity of the first cylinder 4. The outer wall of the first cylinder 4 is slidably adapted to the end of the second cylinder 5 away from the guide shoe 7, and the piston 6 is slidably adapted to the inner wall of the second cylinder 5. The piston 6 divides the inner cavity of the second cylinder 5 into a rod cavity and a rodless cavity. The rod cavity is arranged on the side of the piston 6 close to the first cylinder 4. The side wall of the first cylinder 5 is provided with a third pressure transmission hole 14, and the two ends of the third pressure transmission hole 14 are respectively connected to the rod cavity and the inner cavity of the first cylinder 4. The guide shoe 7 is provided with a flow channel hole 15, and the two ends of the flow channel hole 15 are respectively connected to the rodless cavity and the side of the guide shoe 7 away from the second cylinder 5.

[0018] A conical block 16 is fixedly sleeved on the mandrel 3, one end of the mandrel 3 is slidably set in the aforementioned first core hole, and the other end of the mandrel 3 is slidably set in the aforementioned second core hole. The conical block 16 is set in the large diameter hole 12, and the conical block 16 is adapted to the aforementioned conical surface sealing platform. The spring 17 is sleeved on the mandrel 3, and the two ends of the spring 17 are respectively abutted against the conical block 16 and the end of the first cylinder 4.

[0019] The plugging tool for pressure valve replacement in the wellhead gas tree is used in the initial state. Figure 1 As shown, when it is in use; First, connect the delivery and pressurizing device to the end of the shell 1 away from the guide shoe 7, and deliver the plugging tool to the appropriate position in the pipeline at the front end of the valve to be replaced. It should be understood that in order to achieve the delivery, the overall diameter of the plugging tool and at least the front section diameter of the delivery and pressurizing device are smaller than the diameter of the valve to be replaced when it is opened, and the plugging tool can be directly delivered to the pipeline at the front end of the valve (valve open state) through the valve.

[0020] Then a pressurizing operation is performed, which refers to pumping hydraulic oil (or other media) inward from the end of the housing 1 away from the guide shoe 7 through the feeding and pressurizing device. During the pressurizing process, the hydraulic oil enters the small diameter hole 11 through the first pressure transmission hole 10, and the pressure in the small diameter hole 11 increases. The pressure acts on the conical block 16 to drive the core shaft 3 to move axially as a whole and compress the spring 17. At this time, the conical block 16 is separated from the conical sealing platform and a gap is generated. The hydraulic oil flows into the large diameter hole 12 from the gap. Thereafter, the hydraulic oil flows into the rod cavity of the second cylinder 5 through the second pressure transmission hole 13, the inner cavity of the first cylinder 4, and the third pressure transmission hole 14 in sequence. During this process, the air and other media in the rodless cavity of the second cylinder 5 will be discharged from the flow channel hole 15 without hindrance. As the hydraulic oil in the rod cavity increases, the second cylinder 5 and the guide shoe 7 can be driven to move axially as a whole, so that the rubber cartridge assembly is axially compressed and radially expanded until the outer wall of the rubber cartridge assembly and the inner wall of the pipeline are tightened, thus completing the sealing of the front end pipeline of the valve to be replaced. Since the plugging tool achieves blocking by means of expansion of the rubber cylinder assembly, it is less affected by the unevenness of the inner wall of the pipeline during use, and can effectively solve the problem of difficult selection of the blocking point location.

[0021] Afterwards, the expanded plugging tool is left in the pipeline for plugging, and the delivery and pressurizing device can be disassembled and taken out, and then the valve part can be replaced. Before disassembling the delivery and pressurizing device, the pressurization is stopped. At this time, the spring 17 rebounds to press the conical block 16 against the conical sealing platform to form a seal. At the same time, the elastic force of the rubber cylinder assembly itself also forms an inward tendency force. This tendency force causes the second cylinder 5 and the guide shoe 7 to move axially in the opposite direction, thereby compressing the rod cavity of the second cylinder 5. The hydraulic oil in the rod cavity flows into the large diameter hole 12 through the third pressure transmission hole 14, the inner cavity of the first cylinder 4, and the second pressure transmission hole 13 in turn, and further acts on the conical block 16 to maintain the reliability of the seal there. It can be seen that when the pressurization is stopped and the delivery and pressurizing device is subsequently removed, the plugging tool forms an automatic pressure-maintaining effect inside, which can effectively ensure the reliability of pipeline plugging.

[0022] After the valve component is replaced, the plugging tool needs to be removed. When removing it, the removal tool (for example, a removal sleeve with a diameter smaller than the valve component diameter) can be connected to the end of the shell 1 away from the guide shoe 7 again, and the core shaft 3 is pushed axially in the direction of the guide shoe 7 through a rigid part (for example, a poking rod that can movably penetrate the removal sleeve) to separate the conical block 16 from the conical sealing platform to complete the pressure relief. Under the action of the aforementioned trend force, the rubber cylinder assembly is retracted, thereby quickly achieving unsealing, and then the plugging tool can be removed as a whole by moving the removal tool outward.

[0023] It can be seen from the above operation process that the plugging tool for pressure-changing valves at the wellhead gas tree does not require wellbore pressure operation when used to replace valve parts of the gas tree. It can realize pressure-changing valves and has the advantages of reliable sealing and easy unsealing, and has a relatively simple structure and is easy to use.

[0024] When implementing: The rubber cylinder assembly can use a single rubber cylinder 8, but if the axial size of the single rubber cylinder 8 is too large (the height-to-diameter ratio is too large), its expansion deformation cannot be controlled, and it is difficult to ensure the sealing effect. Therefore, the rubber cylinder assembly includes a plurality of rubber cylinders 8, and the plurality of rubber cylinders 8 are sequentially sleeved outside the second cylinder 5, and a spacer ring 9 is provided between two adjacent rubber cylinders 8.

[0025] Sealing rings are arranged between the core shaft 3 and the first core hole, between the core shaft 3 and the second core hole, between the outer wall of the first cylinder 4 and the end of the second cylinder 5 away from the guide shoe 7, and between the piston 6 and the inner wall of the second cylinder 5 to ensure the sealing pressure transmission effect.

[0026] An end of the housing 1 away from the guide shoe 7 is processed with an internal thread to facilitate the connection or disconnection operation with the aforementioned feeding and pressurizing device, the removal tool and the blocking tool.

[0027] The above is only a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the concept described herein through the above teachings or the technology or knowledge of the relevant field. The changes and modifications made by those skilled in the art shall not deviate from the spirit and scope of the present invention, and shall be within the scope of protection of the claims attached to the present invention.

Claims

1. A plugging tool for pressure valve replacement at a wellhead gas tree without losing control, characterized in that: It includes a coaxially arranged housing, a limiting sleeve, a second cylinder, a rubber cylinder assembly, a guide shoe, a core shaft, a spring, a first cylinder, and a piston; The shell is a hollow cylindrical structure with two ends open, the limit sleeve is fixedly arranged in the middle of the shell, one end of the second cylinder is slidably arranged in one end of the shell, the other end of the second cylinder is fixedly connected to the guide shoe, the rubber cylinder assembly is sleeved outside the second cylinder, and the two ends of the rubber cylinder assembly are respectively abutted against the end of the shell and the end of the guide shoe; The end of the limit sleeve away from the guide shoe is processed with a first core hole and a first pressure transmission hole, and the inside of the limit sleeve is processed with a small diameter hole and a large diameter hole in sequence along the axis toward the other end, and the two ends of the first pressure transmission hole are respectively connected with the small diameter hole and the inner cavity of the end of the shell away from the second cylinder, and the connection part of the small diameter hole and the large diameter hole forms a conical sealing platform; One end of the first cylinder is fixedly inserted into the end of the large diameter hole away from the small diameter hole and is processed with a second core hole and a second pressure transmission hole, the other end of the first cylinder is fixedly connected to the piston, and the two ends of the second pressure transmission hole are respectively connected to the large diameter hole and the inner cavity of the first cylinder; The outer wall of the first cylinder is slidably fitted with the end of the second cylinder away from the guide shoe, the piston is slidably fitted with the inner wall of the second cylinder, the piston divides the inner cavity of the second cylinder into a rod cavity and a rodless cavity, the rod cavity is arranged on the side of the piston close to the first cylinder, a third pressure transmission hole is provided on the side wall of the first cylinder, the two ends of the third pressure transmission hole are respectively connected with the rod cavity and the inner cavity of the first cylinder, the guide shoe is provided with a flow channel hole, the two ends of the flow channel hole are respectively connected with the rodless cavity and the side of the guide shoe away from the second cylinder; A conical block is fixedly sleeved on the core shaft, one end of the core shaft is slidably disposed in the first core hole, the other end of the core shaft is slidably disposed in the second core hole, the conical block is disposed in the large diameter hole, and the conical block is adapted to the conical surface sealing platform; The spring is sleeved on the core shaft, and two ends of the spring are respectively in contact with the conical block and the end of the first cylinder.

2. A plugging tool for pressure valve replacement at a wellhead gas tree without losing the hand according to claim 1, characterized in that: The rubber cylinder assembly comprises a plurality of rubber cylinders, which are sleeved on the outside of the second cylinder in sequence, and a spacer ring is arranged between two adjacent rubber cylinders.

3. The plugging tool for valve replacement under pressure at a wellhead gas tree without losing the hand according to claim 1, characterized in that: Sealing rings are arranged between the core shaft and the first core hole, between the core shaft and the second core hole, between the outer wall of the first cylinder and the end of the second cylinder away from the guide shoe, and between the piston and the inner wall of the second cylinder.

4. The plugging tool for pressure valve replacement at a wellhead gas tree without losing the hand according to claim 1, characterized in that: An end of the shell away from the guide shoe is processed with an internal thread.

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