A hydraulically sealed anchor packer for horizontal wells and its control system

Abstract

This invention relates to the field of oil and gas well production engineering technology, specifically to a hydraulic sealing and anchoring packer for horizontal wells and its control system. The hydraulic sealing and anchoring packer for horizontal wells includes a central tube, a sealing assembly, an anchoring assembly, and a pressure relief assembly. When the central tube slides along its axial direction, the pressure relief assembly can control the high-pressure or low-pressure state of the oil supply area. By setting up a control system, when the pressure relief assembly puts the oil supply area under high pressure, high-pressure hydraulic oil drives the sealing assembly to work, and in conjunction with the control system, drives the anchoring assembly to work; when the pressure relief assembly puts the oil supply area under low pressure, the control system ensures that the reset of the sealing assembly takes precedence over the reset of the anchoring assembly. Therefore, while ensuring reduced wear on the sealing assembly, stable reset of the anchoring assembly is achieved.

Description

Technical Field

[0001] This invention relates to the field of oil and gas well production engineering technology, and in particular to a hydraulic sealing and anchoring packer for horizontal wells and its control system. Background Technology

[0002] With the continued growth of global energy demand, oil and gas field development is extending into deeper and more complex reservoirs. Horizontal well technology has become a key means for the efficient development of unconventional oil and gas resources such as tight oil and shale gas. As oil and gas resource development advances into deeper and more complex reservoirs, horizontal well fracturing technology is showing a development trend of "large-scale, high-pressure, multi-stage, and multi-cluster." Multi-stage, multi-cluster fracturing technology divides the horizontal well section into multiple fracturing stages, and sets up multiple perforation clusters in each stage. High-pressure fracturing fluid is injected into the reservoir to form a complex fracture network, thereby significantly improving single-well productivity and oil and gas recovery.

[0003] In this process system, the hydraulically sealed and anchored packer, as a key downhole tool, primarily undertakes the important functions of sealing the annular space between the tubing and casing, anchoring the tubing string position, and ensuring the precise application of fracturing fluid to the target reservoir. In recent years, with the continuous expansion of fracturing scale, the number of fracturing stages in a single well has increased from a dozen to dozens or even hundreds. The amount of fracturing fluid, sand, and operating pressure per stage has increased significantly, and the stress state of the tubing string under high pressure and high-frequency vibration conditions has become increasingly complex. In large-scale fracturing, the high-speed scouring of the tubing string by high-pressure fracturing fluid and the high-frequency impact generated by the simultaneous initiation of multiple fracture clusters lead to a significant increase in the vibration intensity of the tubing string. This trend places higher demands on the comprehensive performance of the packer and on the response requirements of the control system that realizes the packer's setting function, enabling it to possess more reliable high-pressure sealing capabilities and strong anchoring performance to resist tubing string vibration.

[0004] To mitigate tubing vibration, current packer control systems typically incorporate a hydraulic anchor below the bottom packer. The control system controls the anchor claws to embed them into the casing wall for anchoring. However, after fracturing, a stable oil pressure differential forms between the casing annular space and the tubing. This pressure differential continuously acts on the hydraulic anchor claws, preventing them from retracting properly. At this point, a rigid jamming effect forms between the anchor claws and the casing wall, easily causing tubing jamming during subsequent tubing removal. Summary of the Invention

[0005] Therefore, it is necessary to provide a hydraulic sealing and anchoring packer for horizontal wells to address the problem that current equipment cannot properly retract the anchor claws after fracturing.

[0006] The above objectives are achieved through the following technical solutions: A hydraulically sealed anchor packer for horizontal wells, comprising: A central tube is slidable along its own axis; an oil supply area extending along its own axis is opened inside the central tube, and the oil supply area contains high-pressure hydraulic oil; a first oil hole is opened on the central tube, and the first oil hole is used to allow the high-pressure hydraulic oil in the oil supply area to flow to the outside of the central tube. The sealing assembly, under the action of the high-pressure hydraulic oil, is used to isolate the space between the packer and the sleeve above and below; Anchoring assembly, under the action of the high-pressure hydraulic oil, is used to reduce the vibration of the packer; The pressure relief assembly is used to control the high-pressure or low-pressure state of the oil supply area when the central tube slides along its own axial direction.

[0007] Furthermore, the sealing assembly includes a rubber sleeve and a limiting sleeve, the limiting sleeve being coaxially fixedly disposed at one end of the rubber sleeve; an upper connecting sleeve is coaxially disposed on the outer side of the central tube, the upper connecting sleeve being coaxially clearance-fitted with the central tube and capable of relative sliding with the central tube; a second oil hole is disposed on the upper connecting sleeve, the second oil hole communicating with the first oil hole; the limiting sleeve is coaxially disposed on the outer side of the upper connecting sleeve, the limiting sleeve being used to restrict the rubber sleeve from detaching from the upper connecting sleeve; the rubber sleeve is coaxially disposed on the outer side of the upper connecting sleeve, the rubber sleeve being coaxially clearance-fitted with the upper connecting sleeve, the rubber sleeve expanding radially under the action of the high-pressure hydraulic oil.

[0008] Furthermore, the anchoring assembly includes an anchoring cylinder, an anchor claw, and a first spring; a bushing is coaxially sleeved on the outer side of the central tube, and the bushing is coaxially clearance-fitted with the central tube; the anchoring cylinder is coaxially sleeved on the outer side of the bushing, and is coaxially clearance-fitted with the bushing; the bushing has a third oil hole and a fourth oil hole spaced apart along its own axial direction, and both the third oil hole and the fourth oil hole communicate with the first oil hole; the anchor claw is slidably connected to the anchoring cylinder, and the anchor claw can slide radially along the anchoring cylinder; a detachable pressure plate is provided on the anchoring cylinder, and the pressure plate is slidably connected to the anchor claw; one end of the first spring is fixedly connected to the pressure plate, and the other end is fixedly connected to the anchor claw; the anchor claw slides away from the central tube under the action of the high-pressure hydraulic oil; the elastic force of the first spring always makes the anchor claw tend to slide closer to the central tube.

[0009] Furthermore, the pressure relief assembly includes a connecting rod, a connecting cylinder, a guide head, and a sealing unit. The connecting rod is coaxially threaded to the central tube and slidably coaxially connected to the anchoring cylinder, with a clearance fit. The connecting cylinder is coaxially disposed on the outside of the connecting rod and is threadedly connected. The connecting cylinder is also coaxially clearance fit with the anchoring cylinder. The guide head is coaxially disposed on the outside of the anchoring cylinder and is threadedly connected. The connecting cylinder is coaxially disposed inside the guide head and has a clearance fit. A slit is provided on the guide head, which connects the interior of the guide head to the external environment. The sealing unit is used to control the gap between the central tube and the anchoring cylinder, and to control the communication or isolation between the central tube and the interior of the guide head.

[0010] Furthermore, the sealing unit includes a sealing ring and a spacer ring. The sealing ring is coaxially connected to the connecting rod, and the spacer ring is coaxially connected to the connecting rod. The sealing ring abuts against the spacer ring, and both the sealing ring and the spacer ring are capable of sliding along the axial direction of the connecting rod.

[0011] Furthermore, the contact surface of the anchor claw is made of an elastic material.

[0012] Furthermore, the present invention also provides a hydraulic sealing and anchoring packer control system for horizontal wells, applied to the hydraulic sealing and anchoring packer for horizontal wells described in any of the above-mentioned embodiments; when the pressure relief assembly puts the oil supply area under high pressure, the high-pressure hydraulic oil drives the sealing assembly to work, and in conjunction with the control system, drives the anchoring assembly to work; when the pressure relief assembly puts the oil supply area under low pressure, the control system is used to ensure that the reset of the sealing assembly takes precedence over the reset of the anchoring assembly.

[0013] Furthermore, the control system includes a first current limiting unit and a second current limiting unit. When the pressure relief assembly causes the oil supply area to be in a high-pressure state, the first current limiting unit controls the third oil port to open, and the second current limiting unit controls the fourth oil port to close. When the pressure relief assembly causes the oil supply area to be in a low-pressure state, the first current limiting unit controls the third oil port to close, and the second current limiting unit controls the fourth oil port to open.

[0014] Furthermore, the first flow limiting unit includes a first retaining ring and a second retaining ring; both the first retaining ring and the second retaining ring are coaxially disposed between the bushing and the anchoring cylinder, and are slidably connected to the bushing and the anchoring cylinder; the first retaining ring and the second retaining ring are spaced apart along the axial direction of the anchoring cylinder and abut against each other, and the first retaining ring and the second retaining ring can slide relative to each other along the axial direction of the anchoring cylinder to open or close the third oil hole.

[0015] Furthermore, the second flow-limiting unit includes a slider pin, a retaining ring, and a compression spring. The slider pin is slidably connected to the anchoring cylinder and can slide radially along the anchoring cylinder. The retaining ring is slidably connected coaxially to the anchoring cylinder and abuts against the slider pin. The retaining ring can slide axially along the anchoring cylinder and is used to close or open the fourth oil hole. One end of the compression spring is fixedly connected to the retaining ring, and the other end is fixedly connected to the anchoring cylinder. The elastic force of the compression spring always causes the retaining ring to tend to slide closer to the slider pin. The slider pin and the retaining ring can slide relative to each other to open or close the fourth oil hole.

[0016] The beneficial effects of this invention are: This invention provides a hydraulically sealed and anchored packer for horizontal wells and its control system. The hydraulically sealed and anchored packer for horizontal wells includes a central tube, a sealing assembly, an anchoring assembly, and a pressure relief assembly. The central tube has an axially extending oil supply area containing high-pressure hydraulic oil. A first oil hole is provided on the central tube to allow the high-pressure hydraulic oil to flow to the outside of the central tube. Under the action of the high-pressure hydraulic oil, the sealing assembly isolates the space between the packer and the casing, and the anchoring assembly reduces the vibration of the packer. When the central tube slides axially, the pressure relief assembly controls the oil supply area to switch between high-pressure and low-pressure states. Furthermore, by setting up a control system, when the pressure relief assembly puts the oil supply area in a high-pressure state, the high-pressure hydraulic oil drives the sealing assembly to work, and in conjunction with the control system, drives the anchoring assembly to work; when the pressure relief assembly puts the oil supply area in a low-pressure state, the control system ensures that the reset of the sealing assembly takes precedence over the reset of the anchoring assembly. Therefore, while ensuring reduced wear of the sealing assembly, stable reset of the anchoring assembly is achieved. Attached Figure Description

[0017] Figure 1 This is an overall schematic diagram of a hydraulic sealing and anchoring packer for horizontal wells provided in an embodiment of the present invention; Figure 2 for Figure 1 The main view; Figure 3 for Figure 2 A sectional view along section AA; Figure 4 for Figure 3 A sectional view along section BB. Figure 5 for Figure 3 A sectional view along section CC; Figure 6 for Figure 3 A sectional view along section DD; Figure 7 for Figure 3 A sectional view along section EE; Figure 8 for Figure 3 A magnified view of part of F; Figure 9 for Figure 8 A magnified view of a portion of G; Figure 10 for Figure 1 A schematic diagram of the decomposition process; Figure 11 for Figure 10 An explosion diagram; Figure 12 for Figure 11 A schematic diagram of its breakdown.

[0018] in: 110. Central tube; 111. Oil supply area; 112. First oil hole; 113. Second oil hole; 120. Upper connector; 121. First pin; 122. Second pin; 123. Upper connecting sleeve; 124. Upper pressure cylinder; 125. Limiting cylinder; 126. Rubber sleeve; 127. Fixing cylinder; 128. Middle connecting sleeve; 129. Pressure cap; 130. Bushing; 210. Anchor cylinder; 211. Third oil hole; 212. Fourth oil hole; 213. Anchor claw; 214. First spring; 215. Screw; 216. Pressure plate; 221. First retaining ring; 222. Second retaining ring; 223. Second spring; 224. Third spring; 225. Sliding pin; 226. Retaining ring; 227. Compression spring; 310. Connecting rod; 311. Sealing ring; 312. Spacer ring; 313. Abutment ring; 314. Connecting cylinder; 315. Plug; 316. Guide head; 317. Gap. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below through embodiments and in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0020] The component designations used in this document, such as "first" and "second," are merely for distinguishing the described objects and do not have any sequential or technical meaning. The terms "connection" and "linkage" used in this invention, unless otherwise specified, include both direct and indirect connections (linkages). It should be understood that the terms "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are used only for the convenience of describing the invention and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting the invention.

[0021] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0022] The following reference Figures 1 to 12 This invention describes a hydraulically sealed anchor packer for horizontal wells provided in an embodiment of the present invention.

[0023] The hydraulic sealing and anchoring packer for horizontal wells includes a central tube 110 and an upper connector 120. The upper connector 120 is coaxially sleeved on the outside of the central tube 110 and threadedly engaged with the central tube 110. The upper connector 120 is provided with multiple detachable first pins 121 arranged circumferentially around its own axis, and the upper connector 120 is further detachably connected to the central tube 110 via the first pins 121. Therefore, by driving the upper connector 120 to slide along its own axis, the central tube 110 can be driven to slide along its own axis. Furthermore, the central tube 110 has an oil supply area 111 extending along its own axis, which contains high-pressure hydraulic oil. The central tube 110 has two sets of oil supply channels, which are spaced apart along the axial direction of the central tube 110. Each set of oil supply channels includes multiple first oil holes 112. The multiple first oil holes 112 are arranged circumferentially around the axis of the central tube 110. The oil supply area 111 is connected to the outside of the central tube 110 through the first oil holes 112. The first oil holes 112 are used to allow the high-pressure hydraulic oil in the oil supply area 111 to flow to the outside of the central tube 110.

[0024] The hydraulically sealed and anchored packer for horizontal wells also includes a sealing assembly, an anchoring assembly, and a pressure relief assembly. Both the sealing assembly and the anchoring assembly are located on the outside of the central tube 110.

[0025] Specifically, after the packer is lowered into the casing to a preset depth along with the tubing string, high-pressure hydraulic oil is introduced into the supply zone 111 through the central tube 110. At this time, the pressure relief assembly isolates the supply zone 111 from the area between the packer and the casing, ensuring that the supply zone 111 maintains a high-pressure state. When the high-pressure hydraulic oil flows through the first oil hole 112 and acts on the sealing assembly, the sealing assembly isolates the area between the packer and the casing below from the area between the packer and the casing above, forming an independent sealed area between the packer and the casing below. Simultaneously, when the high-pressure hydraulic oil flows through the first oil hole 112 and acts on the anchoring assembly, the anchoring assembly forms a rigid connection between the packer and the casing, thereby achieving an anchoring effect, reducing the vibration of the packer during fracturing, and significantly reducing the vibration of the entire tubing string.

[0026] In one embodiment, the sealing assembly includes a rubber sleeve 126 and a limiting sleeve 125. An upper connecting sleeve 123 is coaxially disposed on the outer side of the central tube 110, the upper connecting sleeve 123 being coaxially clearance-fitted with the central tube 110 and capable of relative sliding with the central tube 110. The rubber sleeve 126 is coaxially disposed on the outer side of the upper connecting sleeve 123, the rubber sleeve 126 being coaxially clearance-fitted with the upper connecting sleeve 123. The limiting sleeve 125 is coaxially fixedly disposed at one end of the rubber sleeve 126, and is also coaxially disposed on the outer side of the upper connecting sleeve 123, serving to prevent the rubber sleeve 126 from disengaging from the upper connecting sleeve 123. Additionally, an upper pressure sleeve 124 is disposed between the upper connecting sleeve 123 and the upper connector 120. The upper pressure sleeve 124 is threadedly connected to one end of the upper connecting sleeve 123, and the upper pressure sleeve 124 is fixedly connected to the limiting sleeve 125. A fixing sleeve 127 is coaxially sleeved on the outer side of the upper connecting sleeve 123, and the fixing sleeve 127 is fixedly disposed at the other end of the rubber sleeve 126. Furthermore, a second oil hole 113 is provided on the upper connecting sleeve 123, and the second oil hole 113 communicates with the first oil hole 112.

[0027] Furthermore, the anchoring assembly includes an anchoring cylinder 210, an anchor claw 213, and a first spring 214. A bushing 130 is coaxially sleeved on the outer side of the central tube 110, and the bushing 130 is coaxially clearance-fitted with the central tube 110. A middle connecting sleeve 128 is provided between the fixing cylinder 127 and the upper connecting sleeve 123, and the middle connecting sleeve 128 is coaxially sleeved on the outer side of the upper connecting sleeve 123, and the middle connecting sleeve 128 is coaxially clearance-fitted with the central tube 110; the bushing 130 abuts against the middle connecting sleeve 128. A pressure cap 129 is fixedly provided on the middle connecting sleeve 128, and the fixing cylinder 127 is threadedly connected to the pressure cap 129. A plurality of detachable second pins 122 are provided on the middle connecting sleeve 128 in a circumferential arrangement around its own axis, and one end of the middle connecting sleeve 128 is connected to the upper connecting sleeve 123 through the second pins 122. Anchoring cylinder 210 is coaxially sleeved on the outside of bushing 130 and is coaxially clearance fitted with bushing 130. Bushing 130 has a third oil hole 211 and a fourth oil hole 212 spaced apart along its own axial direction, and both the third oil hole 211 and the fourth oil hole 212 are connected to the first oil hole 112.

[0028] Furthermore, the anchor claw 213 is slidably connected to the anchoring cylinder 210, and the anchor claw 213 can slide radially along the anchoring cylinder 210. Specifically, the anchor claw 213 is approximately U-shaped, with its opening facing away from the central tube 110. Figure 5 As shown. Further, the anchoring cylinder 210 is provided with a pressure plate 216 and screws 215. The pressure plate 216 passes through the middle region of the anchor claw 213 and is slidably connected to the anchor claw 213 to prevent the anchor claw 213 from detaching from the anchoring cylinder 210. Simultaneously, both ends of the pressure plate 216 are detachably connected to the anchoring cylinder 210 via screws 215. One end of the first spring 214 is fixedly connected to the pressure plate 216, and the other end is fixedly connected to the anchor claw 213. The elastic force of the first spring 214 always causes the anchor claw 213 to tend to slide closer to the central tube 110.

[0029] In one embodiment, the pressure relief assembly includes a connecting rod 310, a connecting cylinder 314, a guide head 316, and a sealing unit. The connecting rod 310 is coaxially threadedly connected to the central tube 110; the connecting rod 310 is also coaxially slidably connected to the anchoring cylinder 210, and has a clearance fit with the anchoring cylinder 210. The connecting cylinder 314 is coaxially disposed on the outside of the connecting rod 310 and is threadedly connected; the connecting cylinder 314 also has a clearance fit with the anchoring cylinder 210. The guide head 316 is coaxially disposed on the outside of the anchoring cylinder 210 and is threadedly connected. The connecting cylinder 314 is coaxially disposed inside the guide head 316 and has a clearance fit with the guide head 316. Furthermore, a plug 315 is coaxially disposed on the outside of the connecting cylinder 314, and the plug 315 is threadedly connected to the connecting cylinder 314. The plug 315 is disposed near the bottom end of the connecting cylinder 314, spaced apart from the anchoring cylinder 210. The guide head 316 has a slit 317, and multiple sets of slits 317 are arranged circumferentially around the axis of the guide head 316. The slits 317 connect the interior of the guide head 316 with the external environment of the guide head 316, that is, the interior of the guide head 316 is connected to the area between the packer and the sleeve through the slits 317. The sealing unit is used to control the gap between the central tube 110 and the anchoring cylinder 210, and to control the connection or isolation between the central tube 110 and the interior of the guide head 316.

[0030] It is understandable that the interiors of the central tube 110, the connecting rod 310, and the connecting cylinder 314 are interconnected, forming a continuous channel, thereby effectively increasing the volume of the oil supply area 111. The bottom end of the connecting cylinder 314 is a closed structure to prevent high-pressure hydraulic oil from leaking from the bottom, ensuring that the oil supply area 111 forms a stable sealed environment during operation, and ensuring effective pressure transmission and maintenance.

[0031] In one embodiment, the sealing unit includes a sealing ring 311 and a spacer ring 312 coaxially mounted on the connecting rod 310. Both the sealing ring 311 and the spacer ring 312 are slidable along the axial direction of the connecting rod 310. Further, along the axial direction of the connecting rod 310, two sets of sealing rings 311 are arranged, with the two sets of sealing rings 311 abutting against each other. The spacer ring 312 is disposed between the two sets of sealing rings 311 and abuts tightly against both sets of sealing rings 311 to prevent the sealing rings 311 from detaching from the connecting rod 310. An abutment ring 313 is coaxially disposed on the outer side of the connecting rod 310. One end of the abutment ring 313 is fixedly connected to the connecting cylinder 314, and the other end is fixedly connected to the sealing ring 311 near the connecting cylinder 314. The abutment ring 313 and the spacer ring 312 work together to further secure the sealing ring 311 and prevent it from detaching from the connecting rod 310.

[0032] Specifically, during the fracturing operation, the sealing ring 311 and the spacer ring 312 are always in close contact with the inner wall of the anchoring cylinder 210, effectively isolating the gap between the bushing 130 and the central tube 110 from the internal space of the guide head 316, thereby ensuring that the oil supply area 111 is completely separated from the area between the packer and the casing.

[0033] After fracturing is completed, the upper connector 120 drives the central tube 110 to move upward along its own axis, i.e. Figure 3 The vertical movement of the connecting rod 310, sealing ring 311, spacer ring 312, abutment ring 313, connecting cylinder 314, and plug 315 moves upwards as a whole. As the sealing ring 311 and spacer ring 312 disengage from the inner wall of the anchoring cylinder 210, the gap between the bushing 130 and the central tube 110 is connected to the inside of the guide head 316, thereby gradually connecting the oil supply area 111 with the area between the packer and the sleeve, and thus causing the high-pressure hydraulic oil in the oil supply area 111 to be depressurized.

[0034] The present invention also includes a control system for a hydraulically sealed anchor packer for horizontal wells, used to execute a hydraulically sealed anchor packer for horizontal wells according to any of the above embodiments. Further, the control system includes a first flow limiting unit and a second flow limiting unit.

[0035] Specifically, after the packer is lowered into the casing to a preset depth along with the tubing string, high-pressure hydraulic oil is introduced into the oil supply area 111 through the central tube 110. At this time, the sealing ring 311 and the spacer ring 312 remain in close contact with the inner wall of the anchoring cylinder 210, isolating the oil supply area 111 from the area between the packer and the casing, ensuring that the oil supply area 111 maintains a high-pressure state. The high-pressure hydraulic oil then flows sequentially through the first oil hole 112 and the second oil hole 113 to the gap between the rubber sleeve 126 and the upper connecting sleeve 123. Under the action of the high-pressure hydraulic oil, the rubber sleeve 126 expands radially, tightly adhering to the inner wall of the casing, effectively isolating the area between the packer and the casing below and the area between the packer and the casing above, forming an independent sealed area between the packer and the casing below. Simultaneously, high-pressure hydraulic oil flows into the gap between the bushing 130 and the central tube 110 through the first oil hole 112. Due to the action of high-pressure hydraulic oil, the second flow-limiting unit of the control system blocks the fourth oil hole 212, and the first flow-limiting unit of the control system opens the third oil hole 211; thus, the high-pressure hydraulic oil in the gap between the bushing 130 and the central tube 110 flows only through the third oil hole 211 to the gap between the anchor claw 213 and the bushing 130. Furthermore, due to the action of the control system, the high-pressure hydraulic oil flowing through the third oil hole 211 to the gap between the anchor claw 213 and the bushing 130 acts on the anchor claw 213, causing the anchor claw 213 to slide away from the central tube 110, compressing the first spring 214, and then the anchor claw 213 gradually abuts against the inner wall of the casing, realizing a rigid connection between the packer and the casing, thereby achieving the anchoring effect.

[0036] During fracturing, the pressure of the high-pressure hydraulic oil in the supply zone 111 gradually decreases. The first flow-limiting unit of the control system blocks the third oil hole 211, and the second flow-limiting unit of the control system blocks the fourth oil hole 212, so that the high-pressure hydraulic oil in the gap between the anchor claw 213 and the bushing 130 remains at high pressure to ensure the anchoring effect. It can be understood that although the pressure of the high-pressure hydraulic oil in the supply zone 111 gradually decreases, the rubber sleeve 126 remains in an expanded state because the area between the supply zone 111 and the packer and casing is still isolated from each other.

[0037] After fracturing is completed, the upper connector 120 drives the central tube 110 to move upward along its own axis, i.e. Figure 3The vertical movement of the connecting rod 310, sealing ring 311, spacer ring 312, abutment ring 313, connecting cylinder 314, and plug 315 moves upwards as a whole. As the sealing ring 311 and spacer ring 312 disengage from the inner wall of the anchoring cylinder 210, the gap between the bushing 130 and the central tube 110 connects with the interior of the guide head 316, thereby connecting the oil supply area 111 with the area between the packer and the sleeve below, thus releasing the high-pressure hydraulic oil in the oil supply area 111. At this time, because the second oil hole 113 is connected to the first oil hole 112, the rubber sleeve 126 begins to retract and gradually returns to its initial state; then the rubber sleeve 126 gradually loses its sealing function, connecting the area between the packer and the sleeve above and below, and connecting with the oil supply area 111, thereby further reducing the pressure in the oil supply area 111. When the pressure drops to the preset value, the first flow-limiting unit of the control system blocks the third oil hole 211, and the second flow-limiting unit of the control system opens the fourth oil hole 212. The pressure of the high-pressure hydraulic oil in the gap between the anchor claw 213 and the bushing 130 gradually decreases and gradually flows back to the oil supply area 111. At the same time, the first spring 214 begins to rebound and reset, thereby driving the anchor claw 213 to slide and reset towards the central tube 110, so that the anchor claw 213 disengages from the inner wall of the sleeve, completing the unanchoring. Therefore, not only is the stable reset of the anchor claw 213 achieved, but the wear on the rubber sleeve 126 caused by the vibration of the packer is also reduced.

[0038] Specifically, the anchor claws 213 can be configured in multiple sets, and these multiple sets of anchor claws 213 are circumferentially distributed along the axial direction of the anchoring cylinder 210 to further enhance the anchoring effect. Simultaneously, the pressure plate 216, the first spring 214, and the screws 215 used to fix the pressure plate 216, which cooperate with the anchor claws 213, are all configured in multiple sets according to the arrangement of the anchor claws 213. Furthermore, the third oil hole 211 and the fourth oil hole 212 are also configured in multiple sets, with the third oil hole 211 circumferentially arranged around the axial direction of the bushing 130, and the fourth oil hole 212 circumferentially arranged around the axial direction of the bushing 130.

[0039] In one embodiment, the first flow-limiting unit includes a first retaining ring 221 and a second retaining ring 222. Both the first retaining ring 221 and the second retaining ring 222 are coaxially disposed between the bushing 130 and the anchoring cylinder 210, and are slidably connected to both the bushing 130 and the anchoring cylinder 210. The first retaining ring 221 and the second retaining ring 222 are spaced apart along the axial direction of the anchoring cylinder 210 and abut against each other; the first retaining ring 221 and the second retaining ring 222 can slide relative to each other along the axial direction of the anchoring cylinder 210 to open or close the third oil hole 211.

[0040] Furthermore, the first current-limiting unit also includes a second spring 223 and a third spring 224. One end of the second spring 223 is fixedly connected to the anchoring cylinder 210, and the other end is fixedly connected to the first retaining ring 221. One end of the third spring 224 is fixedly connected to the anchoring cylinder 210, and the other end is fixedly connected to the second retaining ring 222.

[0041] In one embodiment, the second flow-limiting unit includes a slider pin 225, a retaining ring 226, and a compression spring 227. The slider pin 225 is slidably connected to the anchoring cylinder 210 and is capable of sliding radially along the anchoring cylinder 210. The retaining ring 226 is coaxially slidably connected to the anchoring cylinder 210 and abuts against the slider pin 225. The retaining ring 226 is capable of sliding axially along the anchoring cylinder 210 and is used to close or open the fourth oil hole 212. One end of the compression spring 227 is fixedly connected to the retaining ring 226, and the other end is fixedly connected to the anchoring cylinder 210. The elastic force of the compression spring 227 always causes the retaining ring 226 to tend to slide closer to the slider pin 225. The slider pin 225 and the retaining ring 226 can slide relative to each other to open or close the fourth oil hole 212.

[0042] Specifically, when high-pressure hydraulic oil is introduced into the oil supply area 111, the high-pressure hydraulic oil flowing into the gap between the bushing 130 and the central tube 110 pushes the first retaining ring 221 and the second retaining ring 222 to slide away from each other, compressing the second spring 223 and the third spring 224 to open the third oil hole 211. Then, the high-pressure hydraulic oil flows through the third oil hole 211 into the gap between the anchor claw 213 and the bushing 130, thereby acting on the anchor claw 213 to achieve the anchoring effect. Simultaneously, the high-pressure hydraulic oil flowing into the gap between the bushing 130 and the central tube 110 pushes the slider pin 225 to slide away from the central tube 110, causing the retaining ring 226 to slide upwards and compress the compression spring 227. Figure 8 In the vertical direction, the fourth oil hole 212 is blocked.

[0043] During fracturing, the pressure of the high-pressure hydraulic oil in the oil supply zone 111 gradually decreases. The first retaining ring 221 and the second retaining ring 222 slide towards each other, causing the second spring 223 and the third spring 224 to reset, thereby sealing the third oil hole 211. At this time, the fourth oil hole 212 remains closed. Therefore, the high-pressure hydraulic oil in the gap between the anchor claw 213 and the bushing 130 is maintained at a high pressure to ensure the anchoring effect.

[0044] After fracturing is completed, the upper connector 120 drives the central tube 110 to move upward along its own axis, i.e. Figure 3The high-pressure hydraulic oil in the oil supply area 111 is depressurized by moving the packer up and down in the vertical direction, thereby connecting the area between the packer and the sleeve below, and the oil supply area 111, thus further reducing the pressure in the oil supply area 111. When the pressure drops to a preset value, the first retaining ring 221 and the second retaining ring 222 block the third oil hole 211; at this time, the high-pressure hydraulic oil in the gap between the anchor claw 213 and the bushing 130 pushes the slider pin 225 to slide towards the center tube 110, causing the retaining ring 226 to slide downwards, i.e. Figure 8 In the vertical direction, the compression spring 227 gradually returns to its original position, opening the fourth oil hole 212. Subsequently, the pressure of the high-pressure hydraulic oil in the gap between the anchor claw 213 and the bushing 130 gradually decreases and gradually flows back to the oil supply area 111. At the same time, the first spring 214 begins to rebound and return to its original position, thereby driving the anchor claw 213 to slide and return to its original position closer to the central tube 110, so that the anchor claw 213 disengages from the inner wall of the sleeve, completing the anchor release.

[0045] In one embodiment, the contact surface of the anchor claw 213 is made of an elastic material and is arc-shaped. The radial dimension of the contact surface of the anchor claw 213 near the pressure plate 216 is larger than the radial dimension of the contact surface away from the pressure plate 216. Specifically, as the anchor claw 213 gradually presses against the inner wall of the sleeve, the contact surface of the anchor claw 213 near the pressure plate 216 contacts the inner wall of the sleeve first and begins to undergo elastic deformation. As the anchor claw 213 continues to slide towards the sleeve, the elastic deformation gradually extends to the contact surface of the anchor claw 213 away from the pressure plate 216, gradually conforming it to the inner wall of the sleeve until the entire anchor claw 213 is tightly fitted with the sleeve, forming a rigid connection. During this process, the contact surface of the anchor claw 213 undergoes progressive compression and deformation, creating a pushing effect that effectively pushes out impurities attached to the inner wall of the sleeve, preventing impurities from getting trapped between the anchor claw 213 and the sleeve, which could lead to poor contact or anchoring failure, thus significantly improving anchoring reliability. At the same time, the U-shaped structure of the anchor claw 213 and the limiting effect of the pressure plate 216 further prevent impurities from entering the movement gap between the anchor claw 213 and the anchoring cylinder 210 from the outside, preventing jamming or malfunction, and ensuring the stable operation of the tool under complex well conditions.

[0046] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0047] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the appended claims.

Claims

1. A hydraulically sealed anchor packer for horizontal wells, characterized in that, include: A central tube is slidable along its own axis; an oil supply area extending along its own axis is opened inside the central tube, and the oil supply area contains high-pressure hydraulic oil; a first oil hole is opened on the central tube, and the first oil hole is used to allow the high-pressure hydraulic oil in the oil supply area to flow to the outside of the central tube. The sealing assembly, under the action of the high-pressure hydraulic oil, is used to isolate the space between the packer and the sleeve above and below; Anchoring assembly, under the action of the high-pressure hydraulic oil, is used to reduce the vibration of the packer; The pressure relief assembly is used to control the high pressure or low pressure state of the oil supply area when the central tube slides along its own axial direction. The anchoring assembly includes an anchoring cylinder, an anchor claw, and a first spring; a bushing is coaxially sleeved on the outside of the central tube, and the bushing is coaxially clearance-fitted with the central tube; the anchoring cylinder is coaxially sleeved on the outside of the bushing and is coaxially clearance-fitted with the bushing; the bushing has a third oil hole and a fourth oil hole spaced apart along its own axial direction, and both the third oil hole and the fourth oil hole are connected to the first oil hole; The pressure relief assembly includes a connecting rod, a connecting cylinder, a guide head, and a sealing unit. The connecting rod is coaxially threaded to the central tube and slidably coaxially connected to the anchoring cylinder, with a clearance fit. The connecting cylinder is coaxially disposed on the outside of the connecting rod and is threadedly connected. The connecting cylinder is also coaxially clearance fit with the anchoring cylinder. The guide head is coaxially disposed on the outside of the anchoring cylinder and is threadedly connected. The connecting cylinder is coaxially disposed inside the guide head and has a clearance fit. A slit is provided on the guide head, connecting the interior of the guide head to the external environment. The sealing unit controls the gap between the central tube and the anchoring cylinder, and the communication or isolation between the central tube and the interior of the guide head.

2. The hydraulic sealing and anchoring packer for horizontal wells according to claim 1, characterized in that, The sealing assembly includes a rubber sleeve and a limiting sleeve. The limiting sleeve is coaxially fixed at one end of the rubber sleeve. An upper connecting sleeve is coaxially disposed on the outer side of the central tube. The upper connecting sleeve is coaxially clearance-fitted with the central tube and can slide relative to the central tube. A second oil hole is provided on the upper connecting sleeve, and the second oil hole communicates with the first oil hole. The limiting sleeve is coaxially disposed on the outer side of the upper connecting sleeve and is used to restrict the rubber sleeve from detaching from the upper connecting sleeve. The rubber sleeve is coaxially disposed on the outer side of the upper connecting sleeve, and the rubber sleeve is coaxially clearance-fitted with the upper connecting sleeve. The rubber sleeve expands radially under the action of the high-pressure hydraulic oil.

3. The hydraulic sealing and anchoring packer for horizontal wells according to claim 2, characterized in that, The anchor claw is slidably connected to the anchoring cylinder, and the anchor claw can slide radially along the anchoring cylinder; a detachable pressure plate is provided on the anchoring cylinder, and the pressure plate is slidably connected to the anchor claw; one end of the first spring is fixedly connected to the pressure plate, and the other end is fixedly connected to the anchor claw; the anchor claw slides away from the central tube under the action of the high-pressure hydraulic oil; the elastic force of the first spring always makes the anchor claw tend to slide closer to the central tube.

4. The hydraulic sealing and anchoring packer for horizontal wells according to claim 3, characterized in that, The sealing unit includes a sealing ring and a spacer ring. The sealing ring is coaxially connected to the connecting rod, and the spacer ring is coaxially connected to the connecting rod. The sealing ring abuts against the spacer ring, and both the sealing ring and the spacer ring are capable of sliding along the axial direction of the connecting rod.

5. The hydraulic sealing and anchoring packer for horizontal wells according to claim 3, characterized in that, The contact surface of the anchor claw is made of an elastic material.

6. A hydraulic sealing and anchoring packer control system for horizontal wells, characterized in that, The hydraulic sealing and anchoring packer for horizontal wells as described in any one of claims 1-5 is used in this application. When the pressure relief assembly puts the oil supply area under high pressure, the high-pressure hydraulic oil drives the sealing assembly to work, and in conjunction with the control system, drives the anchoring assembly to work. When the pressure relief assembly puts the oil supply area under low pressure, the control system is used to ensure that the reset of the sealing assembly takes precedence over the reset of the anchoring assembly.

7. The hydraulic sealing and anchoring packer control system for horizontal wells according to claim 6, characterized in that, The control system includes a first current limiting unit and a second current limiting unit. When the pressure relief assembly puts the oil supply area under high pressure, the first current limiting unit controls the third oil port to open, and the second current limiting unit controls the fourth oil port to close. When the pressure relief assembly puts the oil supply area under low pressure, the first current limiting unit controls the third oil port to close, and the second current limiting unit controls the fourth oil port to open.

8. The hydraulic sealing and anchoring packer control system for horizontal wells according to claim 7, characterized in that, The first flow limiting unit includes a first retaining ring and a second retaining ring; both the first retaining ring and the second retaining ring are coaxially disposed between the bushing and the anchoring cylinder, and are slidably connected to the bushing and the anchoring cylinder; the first retaining ring and the second retaining ring are spaced apart along the axial direction of the anchoring cylinder and abut against each other, and the first retaining ring and the second retaining ring can slide relative to each other along the axial direction of the anchoring cylinder to open or close the third oil hole.

9. The hydraulic sealing and anchoring packer control system for horizontal wells according to claim 7, characterized in that, The second flow limiting unit includes a slider pin, a retaining ring, and a compression spring. The slider pin is slidably connected to the anchoring cylinder and can slide along the radial direction of the anchoring cylinder. The retaining ring is slidably connected to the anchoring cylinder on the same axis and abuts against the slider pin. The retaining ring can slide along the axial direction of the anchoring cylinder, and the retaining ring is used to close or open the fourth oil hole; one end of the compression spring is fixedly connected to the retaining ring, and the other end is fixedly connected to the anchoring cylinder, and the elastic force of the compression spring always makes the retaining ring tend to slide closer to the slider pin; The slider pin and the retaining ring can slide relative to each other to open or close the fourth oil hole.

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