Wellhead device for operating under pressure

Abstract

The present application relates to the technical field of well packer, in particular to a wellhead pressure operation device, the wellhead pressure operation device comprises a delivery hydraulic cylinder, the delivery hydraulic cylinder comprises a piston pipe, a cylinder body and a connecting pipe, the piston pipe has a piston part, the lower end of the piston pipe extends out of the cylinder body and is used for connecting a bridge plug running tool, the upper end of the cylinder body is closed, the upper end of the piston pipe is in the inner cavity of the cylinder body and is provided with a communication port for connecting the piston pipe with the space above the piston part of the cylinder body, the cylinder body or the connecting pipe is provided with a limiting structure for limiting the downward movement stroke of the piston pipe to make the bridge plug running tool realize bridge plug setting through the pressure of the inner cavity of the piston pipe, the delivery of the bridge plug and the setting can be realized in sequence by continuously pressing the delivery hydraulic cylinder, the piston pipe does not need to be pressed and set by penetrating out of the cylinder body upward, the length of the piston pipe can be reduced, and the length of the wellhead pressure operation device is reduced, the hoisting is facilitated, and the operation convenience is facilitated.

Description

Technical Field

[0001] This invention relates to the field of well sealing technology, and more specifically to a wellhead pressurized operation device. Background Technology

[0002] The wellhead gas production tree is a wellhead device used in gas reservoir development for operations such as well opening and closing, pressure regulation, gas volume regulation, and circulating well control. The wellhead gas production tree connects the gas well tubing, casing, and surface process equipment. After long-term service, due to factors such as the composition of the produced gas and valve structure, the wellhead gas production tree may experience malfunctions such as leakage and valve operation failure. This is especially true for wellhead gas production trees in high-sulfur gas reservoirs, where the produced gas components contain sulfides and acidic substances, and the wellhead pressure is high. This can easily lead to wellbore impurities, corrosion products, and mechanical failures, causing gate valve packing leakage, valve stem lifting failure, and other malfunctions. Ultimately, this can result in the need to replace the gate valve or even the entire wellhead gas production tree.

[0003] During wellhead equipment maintenance, to prevent fluid ejection from the well, a common method is to lower a plug into the well for sealing. This involves using coiled tubing to lower the plug into the well, pressurizing the tubing to set the plug, and then releasing the pressure above the plug, reducing the wellhead pressure to zero, thus enabling live-line work. However, using connecting tubing to deploy the plug requires a coiled tubing work vehicle, resulting in higher operating costs.

[0004] Chinese invention patent application CN115012863A discloses a method for changing the wellhead without pressing the well in a high-pressure gas well. The method involves installing a delivery hydraulic cylinder at the wellhead and using the delivery hydraulic cylinder to deliver the setting and releasing mechanism into the well, resulting in low operating costs. The hydraulic cylinder and setting / releasing mechanism form a wellhead pressurized operation device. The hydraulic cylinder includes a cylinder, an extension tube, an upper piston rod, a plunger, and a lower piston rod. The cylinder forms the cylinder body, and the extension tube forms the connecting tube. The upper end of the extension tube is fixedly connected to the bottom of the cylinder, and the lower end of the extension tube is fixedly connected to the upper flange of the No. 1 valve of the wellhead gas production tree via a conversion flange. The plunger is located in the inner cavity of the cylinder body, and the upper piston rod is connected to the center of the upper end face of the plunger. A cylinder sealing seat is provided at the upper end of the cylinder, and the upper piston rod passes through the center hole of the cylinder sealing seat. An upper sealing seat is installed at the upper end of the upper piston rod, and the upper sealing seat has a bypass port that communicates with the center hole of the upper piston rod. The bypass port serves as a liquid inlet and is connected to the hydraulic pump station. A lifting ring is connected to the center of the top of the upper sealing seat for easy crane lifting. The lower piston rod is connected to the center of the lower end face of the plunger, and the lower piston rod extends from the bottom of the cylinder. The central hole extends downwards, and the setting and releasing mechanism is connected to the lower end of the lower piston rod. The central passage of the upper piston rod, plunger, and lower piston rod are sequentially connected and together form the piston tube. The plunger constitutes the piston part of the piston tube. The upper and lower side walls of the hydraulic cylinder are respectively provided with liquid inlets and outlets connected to the hydraulic pump station. The liquid inlets and outlets can be used to pressurize the annulus between the piston tube and the cylinder body. The piston tube can be extended and retracted based on the cylinder body to send the setting and releasing mechanism into the well. The setting and releasing mechanism includes an insertion tool and a bridge plug. The central channel of the piston tube communicates with the inner cavity of the insertion tool. Pressure is applied to the piston tube through the bypass port on the upper sealing seat at the upper end of the piston tube. The insertion tool transmits the setting pressure of the bridge plug and separates from the bridge plug after setting, thus releasing the mechanism. Then, the extension tube is removed from the wellhead device, and the hydraulic cylinder and extension tube are lifted away from the wellhead by a crane, so that well workover operations can be carried out.

[0005] The piston tube of the aforementioned hydraulic cylinder extends through the cylinder body at both the top and bottom to ensure that the upper end of the piston tube pressurizes and the lower end delivers the setting and releasing mechanism. However, after the piston tube descends and completely sends the setting and releasing mechanism into the well, the upper end of the piston tube still needs to extend upwards out of the cylinder body, which requires a very long piston tube. During hoisting, the portion of the piston tube extending upwards out of the cylinder body is very long, requiring a very high hoisting height, which increases the difficulty of hoisting and affects the convenience of operation. Summary of the Invention

[0006] The purpose of this invention is to provide a wellhead pressurized operation device to solve the problem that the piston tube of the hydraulic cylinder of the current wellhead pressurized operation device is too long to extend upward from the cylinder body, which is inconvenient for operation.

[0007] The technical solution of the wellhead pressurized operation device of the present invention is as follows: A wellhead pressurized operation device includes a delivery hydraulic cylinder. The delivery hydraulic cylinder includes a piston tube, a cylinder body, and a connecting pipe connected to the cylinder body for connecting to a wellhead device. The piston tube has a piston portion that mates with the inner wall of the cylinder body. The lower end of the piston tube extends out of the cylinder body and is provided with a connecting structure for connecting a bridge plug insertion tool when a bridge plug is delivered. The upper end of the cylinder body is closed. The upper end of the piston tube is located in the inner cavity of the cylinder body and is provided with a communication port that connects the inner cavity of the piston tube with the space above the piston portion in the inner cavity of the cylinder body. The cylinder body or the connecting pipe is provided with a limiting structure that restricts the downward movement of the piston tube so that when the piston tube moves down to the limiting structure, the pressure in the cylinder body and the inner cavity of the piston tube causes the bridge plug insertion tool to set.

[0008] Furthermore, the lower end of the cylinder body is provided with an inner ring platform, which has a central hole through which the piston tube passes to extend out of the cylinder body. The inner ring platform and the piston tube are in sliding sealing fit. An upward-facing stop step is provided on the inner wall of the cylinder body above the inner ring platform. The stop step is used to stop and fit with the piston. The stop step constitutes the limiting structure.

[0009] Furthermore, the inner wall of the cylinder body is provided with a lower liquid inlet and outlet on the portion located between the inner ring platform and the stop step in the vertical direction. The lower liquid inlet and outlet are connected to the space in the inner cavity of the cylinder body located below the piston and outside the piston tube.

[0010] Furthermore, the piston tube includes a main body, and the piston part includes a piston head connected to the upper end of the main body. A sealing element is provided on the outer wall of the piston head, and a clamping cap for pressing the sealing element is connected to the lower side of the sealing element on the piston head.

[0011] Furthermore, the inner wall of the cylinder is provided with an upper stop structure for limiting the upward movement of the piston. The inner wall of the cylinder is provided with an upper liquid inlet and outlet on the upper side of the upper stop structure. The upper liquid inlet and outlet are connected to the space above the piston in the inner cavity of the cylinder.

[0012] Furthermore, a hoisting assembly structure is provided at the upper end of the cylinder block.

[0013] Furthermore, the wellhead pressurized operation device includes a bridge plug insertion tool, which has a central inner cavity that communicates with the inner cavity of the piston tube, and the bottom of the central inner cavity is provided with a blind plate structure.

[0014] Furthermore, the bridge plug feeding tool includes a setting hydraulic cylinder, which includes a setting piston and a setting cylinder body. The setting piston is connected to the lower end of the piston tube and has a central hole that communicates with the inner cavity of the piston tube. The central cavity includes the central hole of the setting piston. The setting piston and the setting cylinder body form a pressure setting chamber. The wall of the central hole of the setting piston is provided with a pressure transmission hole that connects the pressure setting chamber with the central hole of the setting piston so that pressure can be transmitted to the pressure setting chamber to cause the setting cylinder body to move downward relative to the setting piston.

[0015] Furthermore, the bridge plug insertion tool also includes a retaining outer tube, which is fitted over the setting cylinder body and its upper end is connected to the setting piston.

[0016] Furthermore, the wellhead pressurized operation device includes a retrieval tool, which is equipped with a connecting and mating structure for connecting with the piston tube connection structure when retrieving the bridge plug.

[0017] Beneficial Effects: This invention improves upon existing wellhead live-line working devices by making the upper end of the cylinder body of the hydraulic cylinder for launching the device a closed structure. This allows the upper end of the piston tube to be located within the inner cavity of the cylinder body, with the inner cavity of the piston tube communicating with the space above the piston section within the inner cavity of the cylinder body. After the wellhead live-line working device is fixed to the wellhead device using the connecting pipe, pressure can be applied to the space above the piston section within the inner cavity of the cylinder body. The lower end of the piston tube is blocked by a bridge plug insertion tool. Under pressure, the piston section slides downward relative to the inner wall of the cylinder body, and the piston tube, carrying the bridge plug, is advanced into the wellhead. As the tool and bridge plug move downwards, the bridge plug is inserted into the predetermined position downhole when the piston tube reaches the limiting structure. The piston tube is then stopped and no longer moves downwards. By continuing to pressurize the space above the piston section within the cylinder, the pressure in the cylinder and piston tube is transmitted to the bridge plug, which is then inserted into the tool, thus setting the bridge plug. This method only requires continuous pressurization of the delivery hydraulic cylinder to sequentially deliver and set the bridge plug, eliminating the need for additional pressure to set the piston tube after it extends upwards through the cylinder. This reduces the length of the piston tube and consequently the length of the wellhead pressurized workpiece, facilitating hoisting and improving operational convenience. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of a wellhead pressurized operation device installed on a gas production tree according to an embodiment of the present invention; Figure 2 for Figure 1 A schematic diagram of the hydraulic cylinder connecting the delivery bridge plug and the delivery tool of the wellhead pressurized operation device; Figure 3 for Figure 2 A schematic diagram of the delivery hydraulic cylinder in the middle; Figure 4 for Figure 2 A schematic diagram of the connection structure between the delivery hydraulic cylinder and the bridge plug feeding tool; Figure 5 for Figure 2 A schematic diagram of the bridge plug feeding tool in the middle; Figure 6 for Figure 2 A schematic diagram of the structure at the bridge plug; Figure 7This is a schematic diagram of the wellhead pressurized operation device according to an embodiment of the present invention, showing the connection between the hydraulic cylinder for launching and the fishing tool.

[0019] In the diagram: 100, delivery hydraulic cylinder; 101, lifting ring; 102, upper cap; 103, upper pressure pipe connector; 104, piston head; 105, combined seal; 106, clamping cap; 107, cylinder liner; 108, inner connecting pipe; 109, lower cap; 110, lower pressure pipe connector; 111, extension pipe; 112, flange connector; 113, upward stop step; 114, downward stop step; 200, setting and releasing mechanism; 2001, bridge plug feeding tool; 2002, bridge plug; 201, first-stage piston; 202, retaining outer pipe; 203, first-stage cylinder body; 204, second-stage piston; 205, second-stage cylinder body; 206, third-stage piston; 207, third-stage cylinder body; 208, sealing connector; 2 09. Force transmission cap; 2010. Pressure transmission hole; 2011. Sealed cavity bottom; 210. Pull-off rod; 211. Locking sleeve; 212. Fishing head; 213. Upper center rod; 214. Sealing sleeve; 215. Locking block; 216. Locking ring seat; 217. Locking ring; 218. Lower center rod; 219. Rubber sleeve cap; 220. Outer center tube; 221. End rubber sleeve; 222. Spacer ring; 223. Middle rubber sleeve; 224. Slip seat; 225. Upper connecting cap; 226. Slip sleeve; 227. Slip; 228. Lower connecting cap; 300. Fishing tool; 301. Fishing connector; 302. Fishing tube; 303. Fishing claw; 400. Gas production tree; 401. Wellhead safety valve; 402. Test valve; 500. Completion tubing. Detailed Implementation

[0020] The upper end of the cylinder body of the wellhead live-line working device of the present invention is configured as a closed structure, so that the upper end of the piston tube is located in the inner cavity of the cylinder body and the inner cavity of the piston tube is connected to the space above the piston in the inner cavity of the cylinder body. Thus, after the wellhead live-line working device is fixed to the wellhead device using the connecting pipe, pressure can be applied to the space above the piston in the inner cavity of the cylinder body. The lower end of the piston tube is blocked by the bridge plug insertion tool. Therefore, under pressure, the piston slides downward relative to the inner wall of the cylinder body, and the piston tube, along with the bridge plug insertion tool and the bridge plug, moves downward. When moved to the limiting structure, the bridge plug is sent into the predetermined position downhole, and the piston tube is limited and no longer moves down. In this way, by continuing to pressurize the space above the piston in the inner cavity of the cylinder, the pressure in the inner cavity of the cylinder and the piston tube is transmitted to the inside of the bridge plug insertion tool, thereby achieving bridge plug setting. In this way, only continuous pressurization of the delivery hydraulic cylinder is needed to sequentially deliver and set the bridge plug, without having to pressurize the piston tube upward through the cylinder for setting. This reduces the length of the piston tube, thereby reducing the length of the wellhead pressurized operation device, facilitating hoisting and improving operational convenience.

[0021] Embodiments of the wellhead pressurized operation device of the present invention: like Figure 1 , Figure 2 As shown, the wellhead pressurized workover device includes a delivery hydraulic cylinder 100 and a setting and releasing mechanism 200. The setting and releasing mechanism 200 includes a bridge plug delivery tool 2001 and a bridge plug 2002. By fixing the delivery hydraulic cylinder 100 to the top flange of the gas production tree 400, the delivery hydraulic cylinder 100 delivers the bridge plug delivery tool 2001 and the bridge plug 2002 into the downhole completion tubing 500. The delivery hydraulic cylinder 100 transmits pressure to the bridge plug delivery tool 2001 to set the bridge plug 2002 in the completion tubing 500. The bridge plug 2002 seals the completion tubing 500 near the wellhead, thereby enabling pressurized wellhead workover operations.

[0022] Combination Figure 1 , Figure 2 , Figure 3 , Figure 4 The structure of the delivery hydraulic cylinder 100 is described below. The delivery hydraulic cylinder 100 includes a lifting ring 101, a fixed outer pipe, an upper pressure pipe connector 103, a lower pressure pipe connector 110, and a piston pipe. The fixed outer pipe includes an upper cap 102, a cylinder liner 107, a lower cap 109, an extension pipe 111, and a flange connector 112, which are connected in a threaded and sealed manner from top to bottom. The upper cap 102, cylinder liner 107, and lower cap 109 together constitute the cylinder body of the delivery hydraulic cylinder 100. The extension pipe 111 and the flange connector 112 together constitute the connecting pipe part that connects to the cylinder body and is used to connect to the wellhead device, which is a gas production tree 400. The piston tube includes a main body and a piston section. The main body is an inner connecting pipe 108. The piston section includes a piston head 104. The inner wall of the lower end of the piston head 104 is threadedly sealed to the upper end of the inner connecting pipe 108. A compression cap 106 is threadedly connected to the outer wall of the lower end of the piston head 104. The upper end of the piston head 104 is provided with a downward compression mating surface. A combined sealing element 105 is fitted on the outer wall of the piston head 104 between the compression mating surface and the compression cap 106. The combined sealing element 105 realizes the sliding seal between the piston section and the inner wall of the cylinder liner 107. The compression cap 106 is used to compress the combined sealing element 105 to ensure reliable sealing.

[0023] The lifting ring 101 has an upper ring and a lower threaded connection to the upward-facing connecting hole of the upper cap 102. This upward-facing connecting hole is a blind hole. The lifting ring 101 forms a lifting and mounting structure at the upper end of the cylinder body, facilitating hooking operations with a crane. The lower end of the upper cap 102 has a downward-facing inner cavity with a downward-facing bottom to seal the upper end of the cylinder body and ensure airtightness. The wall of the downward-facing inner cavity of the upper cap 102 has a radially penetrating upper liquid inlet and outlet, where an upper pressure pipe connector 103 is sealed and installed. The upper cap 102 has an internal thread below the upper pressure pipe connector 103 for threaded connection with the upper end of the cylinder liner 107. The piston head 104 and the clamping cap 106 are installed in the inner cavity of the cylinder liner 107 and form a sliding seal through a combined seal 105, which includes multiple sealing rings. The upper internal thread of the lower cap 109 is threaded to the lower external thread of the cylinder liner 107. The lower cap 109 has a radially penetrating lower liquid inlet and outlet below its upper internal thread. A lower pressure transmission pipe connector 110 is sealed and installed at the lower liquid inlet and outlet. The upper end of the inner connecting pipe 108 extends into the inner cavity of the cylinder body. The lower cap 109 has an inner cavity that extends vertically. An inner ring platform is provided in the middle of the inner wall of the lower cap 109. This inner ring platform constitutes the inner ring platform provided at the lower end of the cylinder body. The inner ring platform has a central hole through which the inner connecting pipe 108 passes and extends out of the cylinder body. A sealing ring is provided on the wall of the central hole of the inner ring platform to seal against the outer wall of the inner connecting pipe 108, so that the lower cap 109 and the inner connecting pipe 108 form a sliding sealing fit when the piston tube moves up and down.

[0024] The outer diameter of the clamping cap 106 is larger than the inner diameter of the portion of the lower cap 109 corresponding to the mounting of the lower pressure transmission pipe connector 110. An upward-facing stop step 113 is provided on the upper inner wall of the lower cap 109 below its upper internal thread. This upward-facing stop step 113 forms an upward-facing stop step on the inner wall of the cylinder body, above the inner ring platform. The upward-facing stop step 113 is used to stop the piston. When the piston descends to a certain position, the lower end face of the clamping cap 106 abuts against the upward-facing stop step 113. The stop step constitutes a limiting structure for restricting the downward movement of the piston tube in the cylinder body. The upward-facing stop step 113 restricts the movement of the piston tube, resulting in a simple and reliable structure. The inner diameter of the portion of the lower cap 109 with the stop step is smaller than the inner diameter of the portion with the inner ring platform. The lower liquid inlet and outlet are located on the portion of the inner wall of the lower cap 109 between the inner ring platform and the upward-facing stop step 113 in the vertical direction, facilitating the opening of the lower liquid inlet and outlet. The lower liquid inlet and outlet communicate with the space located below the piston, above the inner ring platform, and around the piston tube in the inner cavity of the cylinder body, so as to realize the liquid inlet and outlet of this space using the lower pressure transmission pipe connector 110. The outer diameter of the piston head 104 is larger than the inner diameter of the part of the upper cap 102 where the corresponding pressure transmission pipe connector 103 is installed. The inner wall of the upper cap 102 is provided with a downward stop step 114 below the upper liquid inlet and outlet. The upper liquid inlet and outlet communicate with the space located above the piston in the inner cavity of the cylinder body. The space located above the piston in the inner cavity of the cylinder body includes the downward inner cavity of the upper cap 102. The downward stop step 114 is located above the cylinder liner 107. The downward stop step 114 constitutes an upper stop structure on the inner wall of the cylinder body for limiting the upward movement stroke of the piston. When the piston tube moves to a certain position, the upper end face of the piston head 104 abuts against the downward stop step 114 to prevent the piston from blocking the upper liquid inlet and outlet.

[0025] The upper part of the flange joint 112 is provided with a long journal and the inner wall of the upper end is threaded to the lower end of the extension pipe 111. The flange at the lower end of the flange joint 112 is provided with a connection hole that matches the top flange of the gas production tree 400, so that the flange joint 112 and the gas production tree 400 can be fixedly connected by bolts. The flange joint 112, extension pipe 111, lower end cap 109, cylinder liner 107, and upper end cap 102 form a sealed inner cavity to prevent gas leakage in the well when the valve of the gas production tree 400 is opened.

[0026] Both the piston head 104 and the inner connecting tube 108 have a central hole that extends vertically. The piston head 104 is located at the upper end of the piston tube. The upper opening of the central hole of the piston head 104 forms a communication port that connects the inner cavity of the piston tube with the space above the piston in the inner cavity of the cylinder. The lower end of the inner connecting tube 108, which extends out of the inner cavity of the cylinder, is connected to the bridge plug insertion tool 2001. The lower end of the bridge plug insertion tool 2001 is connected to the bridge plug 2002. When pressure is applied to the space above the piston in the inner cavity of the cylinder through the pressure pipe connector 103, hydraulic pressure is applied to the bridge plug insertion tool 2001 through the piston tube, thereby driving the piston tube, the bridge plug insertion tool 2001, and the bridge plug 2002 to move downward as a whole. When the clamping cap 106 moves down to the upward stop step 113, the continuous pressure in the inner cavity of the cylinder and the piston tube causes the bridge plug insertion tool 2001 to move, thereby setting the bridge plug 2002. In this way, only continuous pressure on the delivery hydraulic cylinder 100 is needed to sequentially deliver and set the bridge plug 2002. There is no need to push the piston tube upward through the cylinder body and pressurize it for setting. This reduces the length of the piston tube, thereby reducing the length of the wellhead pressurized operation device, which is convenient for hoisting and improves the ease of operation.

[0027] Combination Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5The structure of the bridge plug feeding tool 2001 is described below. The bridge plug feeding tool 2001 includes a piston assembly formed by a first-stage piston 201, a second-stage piston 204, and a third-stage piston 206 connected in a threaded, sealed manner from top to bottom. A cylinder assembly formed by a first-stage cylinder body 203, a second-stage cylinder body 205, and a third-stage cylinder body 207, also connected in a threaded, sealed manner from top to bottom, is fitted onto the piston assembly. Sealing rings are provided on the mating contact surfaces of the piston assembly and the cylinder assembly. The piston assembly and the cylinder assembly together form a setting hydraulic cylinder. The piston assembly forms the setting piston, and the cylinder assembly forms the setting cylinder body. The setting piston is connected to the lower end of the piston tube and has a central hole that communicates with the inner cavity of the piston tube. The central hole of the setting piston is formed by the central holes of the first-stage piston 201, the second-stage piston 204, and the third-stage piston 206. The upper end of the first-stage piston 201 is threadedly connected to the lower end of the inner connecting pipe 108. The lower end of the third-stage piston 206 is threadedly connected to a sealing connector 208. The sealing connector 208 has an upper opening with an upward-facing inner cavity and a lower opening with a downward-facing inner cavity. The part of the sealing connector 208 located between the upper and lower inner cavities forms the cavity bottom and constitutes a blind plate structure. The upward-facing inner cavity of the sealing connector 208 and the central hole of the seated piston together form the central inner cavity of the bridge plug insertion tool 2001, which communicates with the inner cavity of the piston tube. The blind plate structure of the sealing connector 208 forms the closed cavity bottom 2011 of the central inner cavity. When pressure is applied through the pressure-uploading pipe connector 103, the pressure is applied to the closed cavity bottom 2011, which drives the piston tube, the bridge plug insertion tool 2001, and the bridge plug 2002 to move downward as a whole.

[0028] The cylinder assembly is fitted with a retaining outer tube 202. The upper inner wall of the retaining outer tube 202 is threadedly sealed to the upper outer wall of the first-stage piston 201. The retaining outer tube 202 includes a separate upper cylinder section and a lower cylinder section. The upper cylinder section is fixedly connected to the first-stage piston 201, and the lower cylinder section is supported on a step on the outer wall of the third-stage cylinder 207. The inner wall of the retaining outer tube 202 is in sliding contact with each stage of the cylinder assembly, which facilitates reliable assembly of each stage of the cylinder assembly. The three-stage pistons are connected end-to-end in sequence, and the three-stage cylinders are connected end-to-end in sequence. The first-stage piston 201 has a downward-facing stepped surface on its upper part, which is opposite to the upper end face of the second-stage piston 204. The first-stage cylinder 203 has a sliding part that is slidably disposed between the downward-facing stepped surface of the first-stage piston 201 and the upper end face of the second-stage piston 204. A first pressure-setting and sealing cavity is formed between the upper side of the sliding part of the first-stage cylinder 203 and the downward-facing stepped surface of the first-stage piston 201. The first pressure-setting and sealing cavity is surrounded by the first-stage piston 201, the first-stage cylinder 203 and the retaining outer tube 202. The second-stage piston 204 has a downward-facing stepped surface on its upper part, which is opposite to the upper end face of the third-stage piston 206. The second-stage cylinder 205 has a sliding part that is slidably disposed between the downward-facing stepped surface of the second-stage piston 204 and the upper end face of the third-stage piston 206. A second pressure-setting and sealing cavity is formed between the upper side of the sliding part of the second-stage cylinder 205 and the downward-facing stepped surface of the second-stage piston 204. The second pressure-setting and sealing cavity is surrounded by the second-stage piston 204, the second-stage cylinder 205 and the first-stage cylinder 203. The third-stage piston 206 has a downward-facing stepped surface on its upper part, which is opposite to the upper end face of the sealing connector 208. The third-stage cylinder 207 has a sliding part that is slidably disposed between the downward-facing stepped surface of the third-stage piston 206 and the upper end face of the sealing connector 208. A third pressure-setting sealing cavity is formed between the upper side of the sliding part of the third-stage cylinder 207 and the downward-facing stepped surface of the third-stage piston 206. The third pressure-setting sealing cavity is surrounded by the third-stage piston 206, the third-stage cylinder 207 and the second-stage cylinder 205. The central bore of the setting piston is provided with a pressure transmission hole 2010 that connects the pressure setting chamber with the central bore of the setting piston. The first-stage piston 201, the second-stage piston 204, and the third-stage piston 206 are all provided with radially penetrating pressure transmission holes 2010 above the corresponding first-stage cylinder 203, second-stage cylinder 205, and third-stage cylinder 207, so that pressure can be transmitted to each pressure setting chamber to make the setting cylinder move downward relative to the setting piston.

[0029] The inner diameter of the upper end of the first-stage cylinder 203, the second-stage cylinder 205, and the third-stage cylinder 207 is smaller than the inner diameter of the portion below the upper end. Each cylinder has a pressure relief hole located below and immediately adjacent to its upper end. The outer tube 202 also has a pressure relief hole. These holes release the pressure in the cavity below the sliding part of the corresponding cylinder, ensuring the smooth downward movement of the cylinder assembly relative to the piston assembly. The distance between the pressure relief hole on the outer tube 202 and the lowest sealing ring on the outer wall of the upper end of the first-stage cylinder 203 is slightly greater than the maximum axial displacement of the cylinder assembly relative to the piston assembly to ensure a good seal.

[0030] The lower inner cavity of the sealing connector 208 is provided with a thread for connection to the pull rod 210, and a force transmission cap 209 is threadedly connected to the lower outer wall of the third-stage cylinder 207 of the cylinder assembly. The pull rod 210 is connected to the bridge plug 2002, and the force transmission cap 209 is used to apply a downward pressing force to the bridge plug 2002 to achieve setting and release of the bridge plug 2002.

[0031] Combination Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6The structure of the bridge plug 2002 is described below. The bridge plug 2002 includes a setting outer tube assembly formed by a locking sleeve 211, a setting sleeve 214, and a rubber sleeve cap 219 connected sequentially from top to bottom, and a center rod assembly formed by an upper center rod 213 and a lower center rod 218 connected sequentially from top to bottom. An annular space is formed between the setting outer tube assembly and the center rod assembly, and a retrieval head 212, a locking ring seat 216, and a connection to the locking ring are provided above the lower center rod 218 in the annular space. The lower end of the ring seat 216 has a locking ring 217 on its outer wall. The lower end of the retrieval head 212 is pressed against the locking block 215 located at the upper end of the ring seat 216. The upper end of the ring seat 216 has multiple through holes along the circumference. The locking block 215 passes through the through holes. The outer end of the locking block 215 abuts against the inner wall of the retrieval head 212, and the inner end is installed in the groove corresponding to the upper center rod 213. The retrieval head 212 can limit the locking block 215 to maintain the relative position of the ring seat 216 and the upper center rod 213. The upper part of the lower center rod 218 has a downward stepped surface. An outer center tube 220 is fitted on the lower side of the lower center rod 218 outside the stepped surface. The upper part of the outer center tube 220 is hung on the lower end protrusion of the inner cavity of the rubber sleeve cap 219. A sealing ring is provided on the inner wall of the upper end of the outer center tube 220 to seal with the lower center rod 218. A rubber tube assembly consisting of an end rubber tube 221, a spacer ring 222, and a middle rubber tube 223 is fitted below the rubber tube cap 219 on the outer center tube 220. A slip seat 224 is threadedly connected to the outer center tube 220 below the rubber tube assembly. The lower end of the slip seat 224 is provided with an inclined dovetail groove. A slip 227 is inserted into the dovetail groove. The inner end of the slip 227 is installed in the dovetail groove. The outer end of the slip 227 is obliquely inserted into the corresponding opening on the slip sleeve 226. The upper end of the slip sleeve 226 is threadedly connected to an upper connecting cap 225 and is hooked to the protrusion at the lower end of the slip seat 224 through the upper connecting cap 225. The lower inner wall of the slip sleeve 226 is threadedly connected to a lower connecting cap 228. The bottom of the lower connecting cap 228 is closed and has an upward-facing inner cavity. The inner cavity of the lower connecting cap 228 is provided with an internal thread and is threadedly connected to the lower end of the lower center rod 218.

[0032] The force-transmitting cap 209 of the bridge plug insertion tool 2001 is press-fitted onto the upward-facing step at the upper end of the locking sleeve 211. The locking sleeve 211 overlaps with the force-transmitting cap 209. The locking sleeve 211 has circumferentially distributed positioning and retrieval head 212 setting shear pins above the upward-facing step. The force-transmitting cap 209 has slots corresponding to the positions of the setting shear pins for easy installation. The lower inner wall of the locking sleeve 211 has locking threads that mate with the locking ring 217. The upper inner cavity of the upper center rod 213 has threads that connect to the lower end of the pull-off rod 210. The portion between the lower inner cavity and the upper inner cavity of the upper center rod 213 forms a blind plate structure. The lower center rod 218 has an upward-facing inner cavity, and the upper end of the lower center rod 218 is threadedly connected to the lower end of the upper center rod 213. A pressure relief hole is provided on the inner wall of the lower end of the upper center rod 213, and a pressure relief hole is provided on the inner wall of the upper end of the lower center rod 218. Sealing rings are provided on the outer wall of the upper center rod 213 on both the upper and lower sides of its pressure relief hole. This allows the cavity formed by the upper center rod 213 and the lower center rod 218 to communicate with the outer space of the bridge plug 2002 when the retrieval head 212 moves to a certain position relative to the upper center rod 213, thus balancing the air pressure. The total length of the setting and releasing mechanism 200 is not greater than the distance from the lower end face of the inner connecting pipe 108 of the delivery hydraulic cylinder 100 to the lower end face of the flange joint 112, so that the setting and releasing mechanism 200 can be accommodated within the extension pipe 111 and the flange joint 112 before being lowered. The distance from the lower end face of the clamping cap 106 of the delivery hydraulic cylinder 100 to the upward-facing stop step 113 of the lower end cap 109 is at least 0.5 meters longer than the distance from the upper end face of the retrieval head 212 to the upper end face of the completion tubing 500 below the gas production tree 400, ensuring the depth to which the bridge plug 2002 is inserted into the completion tubing 500.

[0033] Under the pushing action of the force-transmitting cap 209 of the bridge plug insertion tool 2001, the setting outer tube assembly moves downward relative to the center rod assembly, causing the bridge plug 2002 to be set. Under pressure, the pull rod 210 is pulled off, releasing the plug. After the bridge plug insertion tool 2001 is removed, the retrieval head 212 is exposed inside the completion tubing 500, so as to facilitate the retrieval tool 300 to retrieve the bridge plug 2002 out of the well.

[0034] Combination Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7The structure of the retrieval tool 300 is described below. The retrieval tool 300 includes a retrieval connector 301, a retrieval cylinder 302, and a retrieval claw 303. The upper end of the retrieval connector 301 is provided with a sealing pipe thread that is threadedly connected to the lower end of the inner connecting pipe 108 of the delivery hydraulic cylinder 100. The lower end external thread of the inner connecting pipe 108 constitutes its connection structure, and the upper end internal thread of the retrieval connector 301 constitutes its connection mating structure. The inner cavity of the retrieval connector 301 is provided with a blind plate structure. The lower end outer wall of the retrieval connector 301 is threadedly connected to the upper end inner wall of the retrieval cylinder 302, and a stabilizing pin is provided between them. The retrieval claw 303 is inserted into the inner cavity of the retrieval cylinder 302. The retrieval claw 303 is used to grasp the retrieval head 212 of the setting and releasing mechanism 200. The length of the retrieval connector 301 is greater than the length of the bridge plug feeding tool 2001 of the setting and releasing mechanism 200, so as to ensure that the retrieval head 212 can be grabbed when the piston tube of the delivery hydraulic cylinder 100 moves downward.

[0035] When using the above-mentioned wellhead pressurized operation device to perform pressurized maintenance on the 400 gas production tree, the process is as follows: 1) Close the wellhead safety valve 401 of the gas production tree 400 to release the pressure inside the gas production tree 400 above the wellhead valve; close the test valve 402 of the gas production tree 400.

[0036] 2) Lifting the delivery hydraulic cylinder 100 and the setting and releasing mechanism 200: On the ground, install the setting and releasing mechanism 200 into the inner cavity of the connecting pipe of the delivery hydraulic cylinder 100. The upper end of the first-stage piston 201 of the setting and releasing mechanism 200 is threadedly sealed to the lower end of the inner connecting pipe 108 of the delivery hydraulic cylinder 100. The upper pressure pipe joint 103 is connected to the pressure-pressurizing line, and the lower pressure pipe joint 110 is connected to the pressure-relief line. The crane lifts the delivery hydraulic cylinder 100 and the setting and releasing mechanism 200 above the gas production tree 400 through the lifting ring 101. The lower end of the flange joint 112 of the delivery hydraulic cylinder 100 is aligned with the upper flange face of the wellhead safety valve 401, and the fixing bolts are tightened.

[0037] 3) Delivery, sealing, and disposal of sealing and disposal mechanisms: 200 ① Deployment: Slowly open the wellhead safety valve 401 and test valve 402 of the gas production tree 400 in sequence. The pressure line transmits hydraulic pressure to the cavity of the deployment hydraulic cylinder 100 located above the piston head 104 through the upper pressure pipe joint 103. The hydraulic pressure acts on the bottom 2011 of the closed cavity, pushing the piston head 104, the combined seal 105, and the clamping cap 106 downward. The inner connecting pipe 108 and the setting release mechanism 200 also move downward. When the lower end face of the clamping cap 106 lands on the upward stop step 113 of the lower end cap 109, the bridge plug 2002 of the setting release mechanism 200 is placed in the completion tubing 500 below the gas production tree 400.

[0038] ② Setting and Release: Increase pressure and continue pressing. Hydraulic pressure is transmitted through the inner cavity of piston head 104 and inner connecting pipe 108 to the bridge plug insertion tool 2001 of the setting and release mechanism 200. Through the pressure transmission holes 2010 of the first-stage piston 201, second-stage piston 204, and third-stage piston 206, pressure is applied into the pressing and setting chamber. The pressure is transmitted to the cylinder assembly of the bridge plug insertion tool 2001, pushing the cylinder assembly downward relative to the piston assembly. The pressure of the cylinder assembly is transmitted through the force transmission pressure... The cap 209 is transferred to the locking sleeve 211. Because the piston tube is limited and no longer moves downwards, the piston assembly of the bridge plug feed tool 2001 connected below the piston tube, as well as the sealing connector 208, pull rod 210, upper center rod 213, lower center rod 218, lower connecting cap 228, slip sleeve 226, and upper connecting cap 225, no longer move downwards. The retrieval head 212 is connected to the upper center rod 213 via a shear pin and is limited by the locking ring seat 216. The locking ring seat 216 is connected to the locking block 21. 5 and the lower center rod 218 are limited, so the hydraulic driving force is transmitted to the locking sleeve 211, causing the locking sleeve 211 to descend relative to the retrieval head 212 and shear the setting seal shear pin between them; the locking sleeve 211 pushes the setting seal sleeve 214, the rubber sleeve pressure cap 219, the outer center tube 220, and the slip seat 224 downward. Since the slip sleeve 226 is stationary, the slip seat 224 descends relative to the slip sleeve 226, pushing the slip 227 along the oblique opening on the slip sleeve 226 and the slip seat 224. The oblique dovetail groove on 24 moves outward and locks onto the inner wall of the completion tubing 500; the hydraulic pressure continues to push the locking sleeve 211, setting sleeve 214, and rubber sleeve cap 219 downward, axially compressing the rubber sleeve assembly to radially expand and seal it onto the inner wall of the completion tubing 500. At this time, the locking sleeve 211 descends and locks onto the locking ring 217, the locking sleeve 211 is fixed, and the bridge plug 2002 is kept in the setting state, completing the locking and setting of the bridge plug 2002 of the setting release mechanism 200. The pressure continues to increase, exceeding the breaking force of the pull rod 210, and the weak middle part of the pull rod 210 is broken by the action of the bridge plug insertion tool 2001 of the setting release mechanism 200. The bridge plug 2002 is released into the completion tubing 500, and then the pressure is released.

[0039] 4) Remove the bridge plug insertion tool 2001 from the delivery hydraulic cylinder 100 and the setting and releasing mechanism 200: Switch the pipelines, connect the upper pressure pipe connector 103 to the pressure relief pipeline, and connect the lower pressure pipe connector 110 to the pressure-pressuring pipeline. The pressure-pressuring pushes the piston head 104, the combined seal 105, and the clamping cap 106 upwards, thereby causing the inner connecting pipe 108 and the bridge plug insertion tool 2001 of the setting and releasing mechanism 200 to move upwards. The force-transmitting cap 209 of the bridge plug insertion tool 2001 separates from the locking sleeve 211, and the sealing connector 208 moves upwards with the upper half of the broken pull rod 210. The bridge plug insertion tool 2001 moves upwards into the inner cavity of the connecting pipe of the delivery hydraulic cylinder 100. Remove the bolts connecting the delivery hydraulic cylinder 100 and the gas extraction tree 400, hoist the delivery hydraulic cylinder 100 together with the bridge plug insertion tool 2001 in its inner cavity, and place it on the ground at the designated location.

[0040] 5) Perform maintenance and upkeep according to the needs of the gas production tree 400, or even replace it with a new gas production tree 400.

[0041] 6) Remove the bridge plug 2002 from the setting and releasing mechanism 200 inside the completion tubing 500: ① Lifting and launching hydraulic cylinder 100 and retrieval tool 300: On the ground, install retrieval tool 300 into the inner cavity of the connecting pipe of hydraulic cylinder 100. The upper end of retrieval connector 301 of retrieval tool 300 is threaded and sealed to the lower end of inner connecting pipe 108 of hydraulic cylinder 100. The upper pressure pipe connector 103 is connected to the pressure-pressurizing line, and the lower pressure pipe connector 110 is connected to the pressure-relief line. The crane lifts hydraulic cylinder 100 and retrieval tool 300 above gas-producing tree 400 through lifting ring 101. The flange connector 112 of hydraulic cylinder 100 is fixed on gas-producing tree 400.

[0042] ② Salvage: Pressurization is achieved by the upper pressure pipe joint 103, which hydraulically pushes the piston head 104, combined seal 105, pressure cap 106, inner connecting pipe 108, and salvage tool 300 downwards. The salvage claw 303 of the salvage tool 300 grabs the upper part of the salvage head 212 of the bridge plug 2002.

[0043] ③ Unsealing and removing bridge plug 2002: Switch pipelines, connect the upper pressure pipe connector 103 to the pressure relief pipeline, and the lower pressure pipe connector 110 to the pressure boosting pipeline. The pressure boosting pushes the piston head 104, combined seal 105, clamping cap 106, and inner connecting pipe 108 upwards, driving the retrieval connector 301 and retrieval cylinder 302 of the retrieval tool 300 upwards. The retrieval cylinder 302 moves upwards relative to the retrieval claw 303, and the retrieval claw 303 retracts and locks the retrieval head 212 under the guidance of the lower inclined surface of the retrieval cylinder 302. Then, under the action of the upward thrust, the retrieval head 212 moves upwards relative to the upper center rod 213 and cuts the unsealing shear pins between them. 212 continues upward, releasing the limit on the locking block 215, and thus releasing the positioning connection between the upper center rod 213 and the locking ring seat 216; the retrieval head 212 moves upward, driving the locking sleeve 211 and the locking ring seat 216 threadedly connected to the locking ring 217 upward; the locking sleeve 211 drives the seated sleeve 214 and the rubber tube pressure cap 219 upward, the rubber tube assembly springs back and contracts, the rubber tube pressure cap 219 continues to move upward with the outer center tube 220 hanging on it, the outer center tube 220 drives the slip seat 224 upward, under the action of the dovetail groove of the slip seat 224 and the oblique opening of the slip sleeve 226, the slip 227 retracts into the opening of the slip sleeve 226, and the bridge plug 2002 is released. Continue to pressurize, driving the retrieval tool 300 and the bridge plug 2002 upward and retracting them into the inner cavity of the connecting pipe of the delivery hydraulic cylinder 100.

[0044] ④ Close the test valve 402, and depressurize the inner cavity of the gas production tree 400 above the test valve 402 and the inner cavity of the connecting pipe of the wellhead pressurized operation device to zero through the well site process, and close the wellhead safety valve 401; disassemble the delivery hydraulic cylinder 100, and hoist the delivery hydraulic cylinder 100 together with the retrieval tool 300 and bridge plug 2002 inside it from the gas production tree 400 and place it on the ground at the designated location.

[0045] 7) Open the gate of the gas-producing tree 400 according to the standard requirements and resume normal production.

[0046] This wellhead pressurized operation device can achieve the deployment, setting, release, and retrieval of the bridge plug 2002 through a single pressurization pipeline. The upper end of the piston tube of the deployment hydraulic cylinder 100 is kept in the inner cavity of the cylinder body to avoid the piston tube being too long and affecting the hoisting. The upper end of the inner cavity of the cylinder body is sealed to effectively ensure the sealing performance. It is simple to operate, safe and reliable, and can effectively save operation time and operation costs.

[0047] In other embodiments, a limiting structure can also be provided in the connecting pipe section. By providing an outer ring platform on the inner connecting pipe and an upward-facing stop surface at the upper end of the flange joint, the upward-facing stop surface constitutes a limiting structure. The outer ring platform of the inner connecting pipe can form a stop fit with the upward-facing stop surface to limit the downward movement stroke of the piston pipe.

[0048] In other embodiments, the upper side of the inner ring platform can be used to form a limiting structure. In this case, the lower liquid inlet and outlet can be set on the upper side of the inner ring platform to facilitate liquid entry.

[0049] In other embodiments, the piston head and the inner connecting tube can also be integrated as a single unit.

[0050] In other embodiments, the connecting pipe section can also be an integral structure, with the extended pipe and flange joint being integrally machined.

[0051] In other embodiments, the setting hydraulic cylinder of the bridge plug feeding tool may also have only one piston and one cylinder body, which is sufficient to satisfy the pressure transmission to the bridge plug.

[0052] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still make modifications to the technical solutions described in the foregoing embodiments without creative effort, or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A wellhead pressurized operation device, comprising a delivery hydraulic cylinder, the delivery hydraulic cylinder including a piston tube, a cylinder body, and a connecting pipe portion connected to the cylinder body and used for connecting a wellhead device, the piston tube having a piston portion that mates with the inner wall of the cylinder body, the lower end of the piston tube extending out of the cylinder body and having a connecting structure for connecting a bridge plug insertion tool when delivering a bridge plug, characterized in that, The upper end of the cylinder body is closed, and the upper end of the piston tube is located in the inner cavity of the cylinder body and is provided with a communication port that connects the inner cavity of the piston tube with the space located above the piston in the inner cavity of the cylinder body. The cylinder body or connecting pipe is provided with a limiting structure that restricts the downward movement of the piston tube so that when the piston tube moves down to the limiting structure, the pressure of the cylinder body and the inner cavity of the piston tube causes the bridge plug to be sent into the tool to achieve bridge plug setting.

2. The wellhead pressurized operation device according to claim 1, characterized in that, The lower end of the cylinder body is provided with an inner ring platform. The inner ring platform has a central hole through which the piston tube passes to extend out of the cylinder body. The inner ring platform and the piston tube are in sliding sealing fit. An upward-facing stop step is provided on the inner wall of the cylinder body above the inner ring platform. The stop step is used to stop the piston and constitutes the limiting structure.

3. The wellhead pressurized operation device according to claim 2, characterized in that, The inner wall of the cylinder body is provided with a lower liquid inlet and outlet on the part between the inner ring platform and the stop step in the vertical direction. The lower liquid inlet and outlet are connected to the space in the inner cavity of the cylinder body located below the piston and outside the piston tube.

4. The wellhead pressurized operation device according to claim 1, 2, or 3, characterized in that, The piston tube includes a main body, and the piston part includes a piston head connected to the upper end of the main body. A seal is provided on the outer wall of the piston head, and a clamping cap for pressing the seal is connected to the lower side of the seal on the piston head.

5. The wellhead pressurized operation device according to claim 1, 2, or 3, characterized in that, The inner wall of the cylinder is also provided with an upper stop structure for limiting the upward movement of the piston. The inner wall of the cylinder is provided with an upper liquid inlet and outlet on the upper side of the upper stop structure. The upper liquid inlet and outlet are connected to the space above the piston in the inner cavity of the cylinder.

6. The wellhead pressurized operation device according to claim 1, 2, or 3, characterized in that, The upper part of the cylinder block is equipped with a hoisting and mounting structure.

7. The wellhead pressurized operation device according to claim 1, 2, or 3, characterized in that, The wellhead pressurized operation device includes a bridge plug insertion tool, which has a central inner cavity that communicates with the inner cavity of the piston tube, and the bottom of the central inner cavity is provided with a blind plate structure.

8. The wellhead pressurized operation device according to claim 7, characterized in that, The bridge plug feeding tool includes a setting hydraulic cylinder, which includes a setting piston and a setting cylinder body. The setting piston is connected to the lower end of a piston tube and has a central hole that communicates with the inner cavity of the piston tube. The central cavity includes the central hole of the setting piston. The setting piston and the setting cylinder body form a pressure setting cavity. The wall of the central hole of the setting piston is provided with a pressure transmission hole that connects the pressure setting cavity with the central hole of the setting piston so that pressure can be transmitted to the pressure setting cavity to cause the setting cylinder body to move downward relative to the setting piston.

9. The wellhead pressurized operation device according to claim 8, characterized in that, The bridge plug insertion tool also includes a retaining outer tube, which is fitted over the setting cylinder body and its upper end is connected to the setting piston.

10. The wellhead pressurized operation device according to claim 1, 2, or 3, characterized in that, The wellhead pressurized operation device includes a retrieval tool, which is equipped with a connection and mating structure for connecting with the piston tube connection structure when retrieving the bridge plug.

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