Blanking plug for plugging sand blasting opening of sand blasting sliding sleeve and plugging method

Abstract

The invention belongs to the technical field of downhole tools, and particularly relates to a blanking plug for plugging a sand blasting opening of a sand blasting sliding sleeve and a plugging method. The blanking plug comprises a central pipe; the center pipe is sleeved with the upper locking claw, after the center pipe enters a well in place, the upper locking claw abuts against the sand blasting sliding sleeve in the axial direction, so that the center pipe can move downwards relative to the upper locking claw, and the upper locking claw can expand in the radial direction after moving axially relative to the center pipe so as to be anchored to the sand blasting sliding sleeve; the upper plugging mechanism is arranged on the outer wall of the central pipe, and after the upper locking claw is anchored, the central pipe moves upwards relative to the upper plugging mechanism, so that the upper plugging mechanism expands in the radial direction to plug the sand blasting sliding sleeve; the lower plugging mechanism is arranged on the outer wall of the central pipe, and the lower plugging mechanism is constructed to be capable of expanding in the radial direction so as to plug the sand blasting sliding sleeve; the upper plugging mechanism and the lower plugging mechanism are arranged on the upper side and the lower side of a sand blasting opening of the sand blasting sliding sleeve correspondingly.

Description

Technical Field

[0001] The present invention belongs to the technical field of downhole tools, and specifically relates to a plugging device for plugging the sandblasting ports of a plugging sandblasting sleeve and a plugging method. Background Art

[0002] In gas field development, casing perforation and multi-packer layered testing and production technologies are mainly adopted. After water production during the testing and production process, the water flooding of the wellbore causes the energy storage of the gas-producing formation to be unable to produce and evaluate normally, seriously affecting the accurate layered reservoir evaluation, geological data acquisition, reserve submission, and production purposes of the testing and production wells. Therefore, accurate water plugging is required.

[0003] Existing packer tools are mainly designed for plugging operations inside the tubing, and are not fully applicable to the operating environment of gas fields. Moreover, they have the following technical defects: First, such tools have poor adaptability to complex plugging operation environments with a large number of reservoir stimulation segments, short segment distances, and limited tool inner diameters; Second, such tools mainly plug the tubing. After positioning through the tubing coupling, plugging is carried out inside the tubing. Their positioning, anchoring, and sealing methods are relatively complex, and their stability is poor; Third, such tools generally use self-expanding rubber barrels without protective bowls, and their temperature and pressure resistance performance is poor, and they cannot be applied to high-temperature and high-pressure working conditions; Fourth, such tools mainly plug the water-producing and gas-producing formations below a certain layer, and cannot achieve the goal of sealing the middle and producing from both ends to realize selective water plugging and gas production; Fifth, for other water plugging methods, if casing internal water plugging technology is adopted, it is necessary to remove the multi-packer layered string and then implement casing internal water plugging. The construction period is long and the cost is high. In addition, it is difficult to remove the string with multiple packers, which is likely to cause downhole accidents and even lead to well abandonment; If chemical plugging is adopted, due to reasons such as small layer segment distances and small inner volumes of the tubing, it is difficult to ensure the accuracy of the plugged layer, and the construction risk is high; There is currently no mature tool for the switchable sliding sleeve tool on the market, with poor reliability and the need to pre-set the sliding sleeve in advance.

[0004] Chinese patent document CN105317393A discloses a movable sealed oil pipe plug for a natural gas well, which proposes a movable sealed oil pipe plug for a natural gas well, including a salvage part, an upper clamping part, a sealing part and a lower clamping part; the upper clamping part includes an upper cava, an upper cone and a compression spring; the upper cava and the upper cone cooperate through a tapered surface, so that when the upper cava moves downward, it expands radially outward under the action of the tapered surface, and then is fixed to the inner wall of the oil pipe, and the compression spring is arranged above the upper cava to provide a downward elastic force for the upper cava. The movable sealed oil pipe plug for a natural gas well of the invention can be seated and sealed at any position in the oil pipe, and the upper cava seat is easier to achieve and is firmer under the action of the compression spring, and the pressure in the oil pipe is sealed effectively and the operation is stable. For smaller inner diameters in the tubing string (such as sliding sleeves), this type of plug has poor passability. If it needs to pass through such small inner diameter sliding sleeves, its diameter must be reduced, resulting in limited space for each part of the tool string in the plug, which makes it difficult to fix the slips well, causing the slips to easily fall off or unstable anchoring. Therefore, this plug has poor adaptability to sealing the lower oil pipe of small inner diameter tools.

[0005] Chinese patent document CN113982527A discloses a small-diameter oil pipe plug, which proposes a small-diameter oil pipe plug, including a starting locking mechanism, which includes a positioning pressure cap, the positioning pressure cap is penetrated by a core shaft, the core shaft does not completely escape from the positioning pressure cap, and the head end of the positioning pressure cap is detachably connected with an elastic locking piece; the air pressure storage power mechanism includes a power push cylinder arranged at the head end of the elastic locking piece, and the core shaft is fixed with a piston push head; the positioning mechanism includes a wing plate assembly arranged at the head end of the power push cylinder, the wing plate assembly is used to position the small-diameter oil pipe plug at the oil pipe coupling, the head end of the wing plate assembly is provided with a retaining spring assembly, the retaining spring assembly is used to make the core shaft slide in one direction, and the head end of the retaining spring assembly is provided with a plurality of hinge slips arranged along the circumferential direction; the sealing mechanism includes an elastic sealing piece, both ends of the elastic sealing piece are provided with extrusion pieces, and the core shaft passes through the two extrusion pieces and the elastic sealing piece. The plugger seals the oil pipe through the pneumatic energy storage power mechanism, hydraulic auxiliary power and lifting force, and positions the plugger at the oil pipe coupling through the wing plate assembly, and anchors the inner wall of the oil pipe through the hinge slip. Although the plugger can seal the lower pipe column through the smaller inner diameter of the pipe column, its positioning, anchoring and sealing methods are relatively complicated, and the oil pipe can only be sealed after being positioned through the oil pipe coupling.

[0006] Chinese patent document CN206376811U discloses an expansion type tubing plug, which includes a lower central rod, a cup seat and a cup sleeved on the lower central rod in sequence from bottom to top, an upper central rod, a slip seat, slips, and an expansion rubber barrel. The cup opens upward, and its maximum outer diameter is larger than the inner diameter of the tubing. The lower end of the upper central rod is connected to the upper end of the lower central rod. The lower end of the slip seat is connected to the upper end of the upper central rod. The slips can be axially slidably arranged on the slip seat, and expand in diameter when sliding downward to abut against the inner wall of the tubing, and contract in diameter when sliding upward to leave the inner wall of the tubing. The expansion rubber barrel is sleeved and fixed on the upper central rod, and expands when encountering water, and is used to seal the inner cavity of the tubing. This plug can overcome the wear of the cup, make up for the defects in the smoothness or roundness of the inner wall of the tubing, has a good sealing effect, and is convenient for large-scale popularization and application. This plug is also used to block the tubing. Besides the defects of conventional tubing plugs, it also lies in that it uses a water-swelling rubber barrel, and its temperature and pressure resistance performance is poor. Summary of the Invention

[0007] In view of the above technical problems, the present invention aims to propose a plug, which can utilize the internal structure inside the sliding sleeve in the pipe string to block a specified sand jet sliding sleeve with high temperature and high pressure water outlet layer, and achieve the purpose of selectively plugging water and producing gas by sealing the middle and producing from both ends.

[0008] The present invention also proposes a plugging method, which uses the plug provided by the present invention to block a specified sand jet sliding sleeve with high temperature and high pressure water outlet layer, and achieve the purpose of selectively plugging water and producing gas by sealing the middle and producing from both ends.

[0009] According to the present invention, there is provided a plug for plugging a sand jet sliding sleeve, including:

[0010] A central pipe;

[0011] An upper locking jaw sleeved outside the central pipe. After the central pipe reaches the well position, the upper locking jaw axially abuts against the sand jet sliding sleeve, so that the central pipe can move downward relative to the upper locking jaw, and the upper locking jaw can radially expand after axially moving relative to the central pipe, so as to be anchored on the sand jet sliding sleeve;

[0012] An upper plugging mechanism arranged on the outer wall of the central pipe. After the upper locking jaw is anchored, the central pipe moves upward relative to the upper plugging mechanism, so that the upper plugging mechanism radially expands to plug the sand jet sliding sleeve;

[0013] A lower plugging mechanism arranged on the outer wall of the central pipe, and the lower plugging mechanism is configured to be able to radially expand to plug the sand jet sliding sleeve;

[0014] The upper plugging mechanism and the lower plugging mechanism are respectively arranged on the upper and lower sides of the sand jet opening of the sand jet sliding sleeve.

[0015] In a preferred embodiment, a liner is provided between the upper locking jaw and the central tube. The upper end of the liner is axially abutted against the upper plugging mechanism, and mutually adapted ratchet teeth are provided on the outer wall of the liner and the inner wall of the upper locking jaw.

[0016] In a preferred embodiment, the upper plugging mechanism comprises:

[0017] A setting cylinder sleeved on the central tube, the upper end of the setting cylinder being axially abutted against the central tube;

[0018] A first rubber cylinder assembly sleeved on the central tube, the upper end of the first rubber cylinder assembly being axially abutted against the lower end of the setting cylinder;

[0019] A push cylinder fixedly arranged on the central tube, the upper end of the push cylinder being abutted against the lower end of the first rubber cylinder assembly.

[0020] In a preferred embodiment, the first rubber cylinder assembly comprises:

[0021] A middle rubber cylinder;

[0022] End rubber cylinders arranged at both axial ends of the middle rubber cylinder;

[0023] And an outer protection bowl and an inner protection bowl arranged at one end of the end rubber cylinder away from the middle rubber cylinder.

[0024] In a preferred embodiment, a movable block is provided between the push cylinder and the central tube, and the central tube pushes the push cylinder to move upward through the movable block.

[0025] In a preferred embodiment, the lower plugging mechanism is configured to radially expand after contacting the liquid in the wellbore, so as to plug the sand jetting sleeve.

[0026] In a preferred embodiment, the lower plugging mechanism comprises:

[0027] Expanding middle rubber;

[0028] Expanding end rubbers arranged at both axial ends of the expanding middle rubber;

[0029] And an inner expansion ring and an outer expansion ring arranged at one end of the expanding end rubber away from the expanding middle rubber;

[0030] The expanding middle rubber and the expanding end rubbers automatically expand after contacting the liquid in the wellbore.

[0031] In a preferred embodiment, a spacer ring is provided between the expanding end rubber and the expanding middle rubber.

[0032] In a preferred embodiment, a lower locking claw is provided outside the central tube. The upper end of the lower locking claw axially abuts against the lower plugging mechanism. When the central tube moves relative to the lower locking claw, the lower locking claw can expand radially, so that the lower locking claw is anchored on the sandblasting sliding sleeve.

[0033] In a preferred embodiment, a guiding cone is provided at the lower end of the central tube. The lower end of the guiding cone is tapered to play a guiding role.

[0034] The outer wall of the guiding cone close to the lower locking claw is tapered. When the central tube drives the guiding cone to move upward, the guiding cone can make the lower locking claw expand radially.

[0035] According to the present invention, a plugging method is also provided, using the plugging device provided by the present invention for plugging.

[0036] Compared with the prior art, the advantages of the present application are as follows.

[0037] In the present invention, an upper locking claw is provided on the central tube. During the process of the central tube entering the well, the upper locking claw can axially abut against the sandblasting sliding sleeve, so as to achieve precise positioning.

[0038] In the present invention, an upper plugging mechanism and a lower plugging mechanism are provided on the central tube. The upper plugging mechanism realizes radial expansion by the upward movement of the central tube to plug the sandblasting sliding sleeve, and the lower plugging mechanism plugs the sandblasting sliding sleeve by self-expansion. The upper plugging mechanism and the lower plugging mechanism are respectively located on the axial two sides of the sandblasting port of the sandblasting sliding sleeve, so as to plug the upper and lower sides of the sandblasting port axially at the same time. The central tube can be used for gas production, realizing the purpose of selectively plugging water and producing gas by plugging the middle and producing from both ends. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The present invention will be described below with reference to the accompanying drawings.

[0040] Figure 1 A schematic diagram of an embodiment showing the plugging device of the present invention entering the sandblasting sliding sleeve and the upper locking claw not yet being anchored;

[0041] Figure 2 A schematic diagram of an embodiment showing the plugging device of the present invention entering the sandblasting sliding sleeve to complete plugging and releasing;

[0042] Figure 3 A schematic diagram of an embodiment showing the plugging device of the present invention;

[0043] Figure 4 A schematic diagram of an embodiment showing the releasing joint of the present invention;

[0044] Figure 5a A schematic diagram of an embodiment showing the central tube of the present invention;

[0045] Figure 5b shows Figure 5a a partial enlarged schematic view of part A in , that is, a schematic view of the ratchet teeth between the central tube and the liner;

[0046] Figure 5c shows Figure 5a a sectional structure schematic view of part B in , that is, a schematic view of the groove on the central tube for installing the movable block;

[0047] Figure 6a shows a schematic view of an embodiment of the setting cylinder of the present invention;

[0048] Figure 6b shows Figure 6a a sectional structure schematic view of part C in ;

[0049] Figure 7 shows a schematic view of an embodiment of the first rubber cylinder assembly of the present invention;

[0050] Figure 7a shows a schematic view of an embodiment of the inner protection bowl of the present invention;

[0051] Figure 7b shows a schematic view of an embodiment of the outer protection wrist of the present invention;

[0052] Figure 7c shows a schematic view of an embodiment of the end rubber cylinder of the present invention;

[0053] Figure 7d shows a schematic view of an embodiment of the middle rubber cylinder of the present invention;

[0054] Figure 8 shows a schematic view of an embodiment of the pushing cylinder of the present invention;

[0055] Figure 9 shows a schematic view of an embodiment of the movable block of the present invention;

[0056] Figure 10 shows a schematic view of an embodiment of the retaining cylinder of the present invention;

[0057] Figure 11a shows a schematic view of an embodiment of the anti-backlash ring of the present invention;

[0058] Figure 11b shows a sectional schematic view of the anti-backlash ring of the present invention;

[0059] Figure 11c shows Figure 11b an enlarged schematic view of part D of ;

[0060] Figure 12aShows a schematic diagram of an embodiment of the liner of the present invention;

[0061] Figure 12b Shows Figure 12a An enlarged schematic diagram of part E in, i.e., a schematic diagram of the ratchet teeth between the liner and the upper locking claw;

[0062] Figure 12c Shows Figure 12a A sectional schematic diagram of part F in;

[0063] Figure 13a Shows a schematic diagram of an embodiment of the upper locking claw of the present invention;

[0064] Figure 13b Shows Figure 13a A sectional schematic diagram of part A in;

[0065] Figure 13c Shows Figure 13a A sectional schematic diagram of part B in;

[0066] Figure 13d Shows Figure 13a A sectional schematic diagram of part C in;

[0067] Figure 13e Shows Figure 13a An enlarged schematic diagram of part D in, i.e., a structural schematic diagram of the ratchet teeth between the upper locking claw and the liner;

[0068] Figure 14 Shows a schematic diagram of an embodiment of the retaining ring of the present invention;

[0069] Figure 15 Shows a schematic diagram of an embodiment of the lower plugging mechanism of the present invention;

[0070] Figure 15a Shows a schematic diagram of an embodiment of the outer expansion ring of the present invention;

[0071] Figure 15b Shows a schematic diagram of an embodiment of the inner expansion ring of the present invention;

[0072] Figure 15c Shows a schematic diagram of an embodiment of the expansion end glue of the present invention;

[0073] Figure 15d Shows a schematic diagram of an embodiment of the spacer ring of the present invention;

[0074] Figure 15e Shows a schematic diagram of an embodiment of the expansion middle glue of the present invention;

[0075] Figure 16a Shows a schematic diagram of an embodiment of the lower locking ring of the present invention;

[0076] Figure 16b Shows a top view schematic diagram of the lower locking ring of the present invention;

[0077] Figure 17 Shows a schematic diagram of an embodiment of the guiding cone of the present invention;

[0078] Figure 18 Shows a schematic diagram of an embodiment of the sandblasting sliding sleeve of the present invention;

[0079] Figure 18a Shows a schematic diagram of an embodiment of the upper joint of the present invention;

[0080] Figure 18b Shows a schematic diagram of an embodiment of the outer cylinder of the present invention;

[0081] Figure 18c Shows a schematic diagram of an embodiment of the sliding sleeve core of the present invention;

[0082] Figure 18d Shows a schematic diagram of an embodiment of the snap ring of the present invention;

[0083] Figure 18e Shows a schematic diagram of an embodiment of the lower joint of the present invention.

[0084] In the figure: 11, upper joint; 12, outer cylinder; 121, sandblasting port; 13, sliding sleeve core; 14, snap ring; 15, lower joint;

[0085] 21, releasing joint; 22, releasing shear pin; 23, central tube; 24, setting cylinder; 241, avoidance hole; 25, outer protective bowl; 26, inner protective bowl; 27, end rubber cylinder; 28, middle rubber cylinder; 29, pushing cylinder; 210, movable block; 211, retaining cylinder; 212, anti-backlash ring; 213, liner; 214, upper locking claw; 215, shear pin; 216, sealing ring; 217, locking ball; 218, retaining ring; 219, outer expansion ring; 220, inner expansion ring; 221, expansion end rubber; 222, spacer ring; 223, expansion middle rubber; 224, anti-rotation pin; 225, lower locking claw; 226, guiding cone; 101, upper plugging mechanism; 102, lower plugging mechanism; 103, first rubber cylinder assembly; 100, plug; 200, sandblasting sliding sleeve.

[0086] In this application, all the drawings are schematic drawings, only used to illustrate the principle of the present invention and not drawn according to the actual ratio. Detailed implementation manners

[0087] The present invention will be introduced below with reference to the drawings.

[0088] It should be noted that in this application, the direction close to the wellhead after installation in the well according to the present invention is described as "up", "front" or similar terms, while the direction close to the bottom of the well is described as "down", "rear" or similar terms.

[0089] Figure 18 FIG. 4 is a schematic structural view of the sandblasting sliding sleeve 200 provided according to the present invention. As Figure 18 shown, the sandblasting sliding sleeve 200 includes an upper joint 11, an outer cylinder 12, a sliding sleeve core 13 and a lower joint 15.

[0090] The lower end of the upper joint 11 is coaxially and sealingly fixedly sleeved inside the outer cylinder 12. The upper end of the lower joint 15 is coaxially and sealingly fixedly sleeved inside the outer cylinder 12. The sliding sleeve core 13 is coaxially and sealingly sleeved inside the outer cylinder 12, and the lower end surface of the sliding sleeve core 13 contacts the upper end surface of the lower joint 15. A snap spring 14 for restricting the relative axial movement between the two is provided between the sliding sleeve core 13 and the outer cylinder 12. At least one sandblasting port 121 is provided on the side wall of the outer cylinder 12, and the sandblasting port 121 is located between the upper joint 11 and the sliding sleeve core 13.

[0091] Figure 3 FIG. 5 shows the structure of the plug 100 of the present invention. As Figure 3 shown, the plug 100 includes a central tube 23, an upper locking claw 214, an upper plugging mechanism 101 and a lower plugging mechanism 102.

[0092] Among them, the upper locking claw 214 is fixedly sleeved outside the central tube 23 through a shear pin 215. Figure 1 And Figure 2 FIG. 6 is a schematic structural view of the plug 100 of the present invention reaching the position of the sandblasting sliding sleeve 200 after being lowered into the well. Combining Figures 1 - 3 shown, during the process of the plug 100 entering the sandblasting sliding sleeve 200, the upper locking claw 214 will axially abut against the sandblasting sliding sleeve. Specifically, the outer diameter of the upper part of the upper locking claw 214 is larger than that of the lower part, and the sliding sleeve core 13 of the sandblasting sliding sleeve 200 can allow the lower part of the upper locking claw 214 to pass through and axially abut against the upper part of the upper locking claw 214. In this case, by continuously moving the central tube 23 downward, the shear pin 215 for fixing the upper locking claw 214 and the central tube 23 can be cut off, so that the central tube 23 can move downward relative to the upper locking claw 214. After the upper locking claw 214 axially moves relative to the central tube 23, it can radially expand and thus be anchored on the sliding sleeve core 13 of the sandblasting sliding sleeve 200.

[0093] As Figure 3 shown, the upper plugging mechanism 101 is provided on the outer wall of the central tube 23 and is located above the upper locking claw 214. Combining Figures 1 - 3As shown, after the upper locking claw 214 is anchored to the inner wall of the sleeve core 13 of the sandblasting sleeve 200, the upper plugging mechanism 101 expands radially above the sandblasting port 121 to plug the sandblasting sleeve 200. In this embodiment, after the upper plugging mechanism 101 expands radially, it plugs the upper joint 11 of the sandblasting sleeve 200.

[0094] The lower plugging mechanism 102 is arranged on the outer wall of the central pipe 23 and is located below the upper locking claw 214. In this embodiment, after the upper locking claw 214 is anchored to the inner wall of the sleeve core 13 of the sandblasting sleeve 200, the lower plugging mechanism 102 can expand radially to plug the lower part of the sandblasting port 121. Specifically, in this embodiment, the sleeve core 13 of the sandblasting sleeve 200 is plugged.

[0095] The upper plugging mechanism 101 and the lower plugging mechanism 102 are respectively arranged on the upper and lower sides of the sandblasting port 121 of the sandblasting sleeve 200, so as to plug the upper and lower axial sides of the sandblasting port 121 at the same time. The central pipe 23 can be used for gas production, achieving the purpose of selectively plugging water and producing gas by sealing the middle and producing from both ends.

[0096] According to the present invention, in a specific embodiment, a liner 213 is arranged between the upper locking claw 214 and the central pipe 23, and the upper end of the liner 213 is axially abutted against the upper plugging mechanism 101. Specifically, the liner 213 is sleeved on the outside of the central pipe 23, the upper locking claw 214 is sleeved on the outside of the liner 213, and the shear pin 215 fixes the upper locking claw 214 and the liner 213. The upper end size of the liner 213 is larger than the size of the upper locking claw 214, and mutually adapted ratchet teeth are arranged on the outer wall of the liner 213 and the inner wall of the upper locking claw 214. When the central pipe 23 drives the liner 213 and the upper locking claw 214 to move downward until the upper locking claw 214 abuts against the sleeve core 13, the upper locking claw 214 cannot continue to move downward, while the central pipe 23 drives the liner 213 to continue to move downward, thereby cutting the shear pin 215, and the part with a larger outer diameter at the upper part of the liner 213 moves to the radial inner side of the upper locking claw 214, causing the upper locking claw 214 to expand radially, so that the upper locking claw 214 is anchored on the sleeve core 13. Due to the existence of ratchet teeth between the liner 213 and the upper locking claw 214, the liner 213 cannot move upward relative to the upper locking claw 214, thereby preventing the anchoring failure of the upper locking claw 214.

[0097] According to the present invention, in a specific embodiment, a retaining ring 218 is sleeved on the outside of the liner 213. The cross section of the retaining ring 218 is L-shaped and is located below the upper locking claw 214. A lock ball 217 capable of moving radially is arranged in the side wall of the liner 213, and a ball groove for accommodating the lock ball 217 is arranged on the outer wall of the central pipe 23. Before the upper locking claw 214 is anchored, the lower end of the upper locking claw 214 extends into the inner side of the retaining ring 218, as Figure 3As shown, the outer wall of the lower end of the upper locking claw 214 contacts the inner wall of the retaining ring 218, the inner wall of the lower end of the upper locking claw 214 contacts the locking ball 217. The locking ball 217 is located within the side wall of the liner 213, and a partial volume of the locking ball 217 is located within the ball groove on the outer wall of the central tube 23. In this setting, when the central tube 23 moves downward, the central tube 23 can drive the liner 213 to move downward through the locking ball 217. When the upper locking claw 214 moves upward relative to the liner 213 until the upper locking claw 214 is anchored, the lower end portion of the upper locking claw 214 disengages from the retaining ring 218. At this time, when the central tube 23 is lifted, the upper locking claw 214 cannot move because it is anchored on the sliding sleeve core 13, and the liner 213 cannot move upward due to the one-way ratchet teeth between the liner 213 and the upper locking claw 214, enabling the locking ball 217 to move radially outward, thereby disengaging from the ball groove of the central tube 23, and the central tube 23 will move upward relative to the liner 213.

[0098] As Figure 5a and Figure 5b As shown, a one-way ratchet is provided between the central tube 23 and the liner 213, and this ratchet prevents the central tube 23 from moving downward relative to the liner 213. A retaining ring 212 is also provided between the central tube 23 and the liner 213, and the retaining ring 212 is located above the one-way ratchet between the central tube 23 and the liner 213.

[0099] According to the present invention, the upper plugging mechanism 101 includes a setting cylinder 24, a first rubber cylinder assembly 103, and a pushing cylinder 29.

[0100] Among them, the setting cylinder 24 is slidably sleeved outside the central tube 23, the first rubber cylinder assembly 103 is sleeved outside the setting cylinder 24. The outer diameter of the upper end portion of the setting cylinder 24 is larger than that of the lower portion, and the top of the first rubber cylinder assembly 103 axially abuts against the upper end portion of the setting cylinder 24. In the initial state (the state where the upper locking claw 214 is anchored), the upper end of the setting cylinder 24 axially abuts against the central tube 23. The pushing cylinder 29 is fixedly sleeved outside the central tube 23, and the upper end of the pushing cylinder 29 contacts the first rubber cylinder assembly 103.

[0101] According to the description of the above working principle, after the upper locking claw 214 is anchored, the central tube 23 is lifted, causing the central tube 23 to move upward relative to the liner 213. At the same time, the lower end of the setting cylinder 24 is fixedly connected to the liner 213, so that the central tube 23 can drive the pushing cylinder 29 to move upward relative to the setting cylinder 24, applying pressure to the first rubber cylinder assembly 103 to cause it to expand radially and complete the setting.

[0102] Further, the push cylinder 29 is fixedly connected to the central tube 23 through the movable block 210. Grooves for installing the movable block 210 are provided on both the outer wall of the central tube 23 and the inner wall of the push cylinder 29, so that part of the volume of the movable block 210 is located inside the central tube 23 and part of the volume is located inside the push cylinder 29. The arrangement of the movable block 210 axially fixes the push cylinder 29 and the central tube 23 on one hand, and on the other hand, there is a gap between the upper inner wall of the push cylinder 29 and the outer wall of the central tube 23 that can accommodate the setting cylinder 24.

[0103] In a specific embodiment, the structure of the groove of the central tube 23 for installing the movable block 210 is as Figure 5c shown, and the four grooves are evenly distributed on the outer wall of the central tube 23 in the circumferential direction.

[0104] As Figure 3 Figure 6a and Figure 6b shown, four avoidance holes 241 for avoiding the movable block 210 are evenly arranged on the side wall of the setting cylinder 24 in the circumferential direction. The movable block 210 is located in the avoidance holes 241, and the axial length of the avoidance holes 241 is greater than that of the movable block 210. A thread for connecting the liner 213 is provided on the lower outer wall of the setting cylinder 24. Further, in order to further strengthen the connection between the setting cylinder 24 and the liner 213, they are also fixedly connected by pins at the threaded connection position.

[0105] A retaining cylinder 211 is arranged at the lower end of the push cylinder 29 by means of threaded connection. The upper end of the retaining cylinder 211 extends into the interior of the push cylinder 29, and the upper end surface of the retaining cylinder 211 forms the lower end surface of the groove for installing the movable block 210. By disassembling the retaining cylinder 211, the movable block 210 can be conveniently installed between the push cylinder 29 and the central tube 23. And, in the initial state, the lower end of the retaining cylinder 211 abuts against the upper end surface of the liner 213, so that the retaining cylinder 211 can push the liner 213 downward during the process of the central tube 23 driving the liner 213 to move downward to anchor the locking claw 214.

[0106] According to the present invention, in a specific embodiment, the first rubber cylinder assembly 103 includes a middle rubber cylinder 28 and end rubber cylinders 27. The two end rubber cylinders 27 are respectively arranged at the upper and lower ends of the middle rubber cylinder 28, and the contact surfaces of the end rubber cylinders 27 and the middle rubber cylinder 28 are both set as inclined surfaces. Outer protection bowls 25 and inner protection bowls 26 are arranged at the ends of the two end rubber cylinders 27 far from the middle rubber cylinder 28, and the inner protection bowls 26 are located inside the outer protection bowls 25.

[0107] In a specific embodiment provided by the present invention, the lower plugging mechanism 102 is configured to expand after contacting the liquid in the wellbore, so as to plug the sandblasting sliding sleeve 200.

[0108] Specifically, asFigure 3 As shown, the lower plugging mechanism 102 includes an expanding middle glue 223 and expanding end glues 221. The two expanding end glues 221 are respectively arranged on the upper and lower sides of the expanding middle glue 223, and both the expanding middle glue 223 and the expanding end glues 221 are made of self-expanding materials, which are common materials in the field of downhole tools and automatically expand after contacting downhole fluids.

[0109] Inner expanding rings 220 and outer expanding rings 219 are arranged at one ends of the two expanding end glues 221 far away from the expanding middle glue 223. The inner expanding rings 220 are arranged inside the outer expanding rings 219, that is, the inner expanding rings 220 are located between the outer expanding rings 219 and the expanding end glues 221, and one end of the expanding end glue 221 in contact with the inner expanding ring 220 is set as an inclined surface.

[0110] In a preferred embodiment, a spacer ring 222 is arranged between the expanding end glue 221 and the expanding middle glue 223.

[0111] According to the present invention, a lower locking claw 225 is arranged outside the central tube 23. As Figure 3 shown, the upper end of the lower locking claw 225 is fixedly connected to the liner 213 and axially abuts against the lower end of the lower plugging mechanism 102. When the central tube 23 moves upward relative to the lower locking claw 225, the lower locking claw 225 can be radially expanded, so that the lower locking claw 225 is anchored on the sandblasting sliding sleeve 200. In this embodiment, the lower locking claw 225 is anchored on the lower joint 15 of the sandblasting sliding sleeve 200.

[0112] In a specific embodiment, a guiding cone 226 is coaxially and fixedly arranged at the lower end of the central tube 23, and the lower end of the guiding cone 226 is set as a cone to play a guiding role. Specifically, the outer wall of the guiding cone 226 close to the lower locking claw 225 is set as a cone. When the central tube 23 drives the guiding cone 226 to move upward relative to the liner 213 and the lower locking claw 225, the lower end of the lower locking claw 225 contacts the conical surface of the guiding cone 226. Under the action of the conical surface of the guiding cone 226, the lower locking claw 225 is gradually radially expanded, so as to be anchored on the sandblasting sliding sleeve 200.

[0113] According to the present invention, a plugging method is also provided, which uses the plug 100 provided by the present invention for plugging, including the following steps.

[0114] A releasing joint 21 is installed at the upper end of the central tube 23 of the plug 100 through a releasing shear pin 22. The upper end of the releasing joint 21 is connected to a tubing or other downhole tools, so as to send the plug 100 into the well. The specific joint of the releasing joint 21 in this embodiment is as Figure 4As shown, after the central pipe 23 is sleeved inside the releasing joint 21, the top end of the central pipe 23 is in axial contact with the releasing joint 21, facilitating the alignment of the holes for installing the releasing shear pin 22 on the central pipe 23 and the releasing joint 21.

[0115] As Figure 1 shown, the plug 100 is moved downward into the sandblasting sliding sleeve 200 provided in the well. When the locking claw 214 of the plug 100 is axially abutted against the sliding sleeve core 13 of the sandblasting sliding sleeve 200, a downward pressure is continuously applied to the central pipe 23 through the releasing joint 21, so that the central pipe 23 drives the liner 213 to move downward through the locking ball 217, the movable block 210, and the retaining cylinder 211. Then, the large-sized part at the upper part of the liner 213 generates a radially outward force on the locking claw 214, causing the locking claw 214 to expand radially and be anchored on the sliding sleeve core 13.

[0116] After that, the central pipe 23 is lifted through the releasing joint 21, and the locking ball 217 disengages from the central pipe 23, thus losing the locking function and enabling the central pipe 23 to move upward relative to the liner 213. At this time, the central pipe 23 drives the pushing cylinder 29 to move upward. The lower end of the setting cylinder 24 is fixedly connected to the liner 213, so that the pushing cylinder 29 can squeeze the first rubber cylinder assembly 103 together with the setting cylinder 24, causing the first rubber cylinder assembly 103 to seal the upper joint 11 of the sandblasting sliding sleeve 200, as Figure 2 shown. At the same time, the central pipe 23 moves upward relative to the lower locking claw 225 fixed to the lower part of the liner 213, so that the conical surface of the guiding cone 226 fixed to the lower end of the central pipe 23 cooperates with the lower locking claw 225, causing the lower locking claw 225 to expand radially outward and be anchored on the lower joint 15 of the sandblasting sliding sleeve 200. When there is fluid at the position of the lower plugging mechanism 102, the lower plugging mechanism 102 automatically expands to plug the sliding sleeve core 13 of the sandblasting sliding sleeve 200.

[0117] Finally, the releasing joint 21 is continuously lifted until the releasing shear pin 22 for connecting the releasing joint 21 is cut off, and the releasing joint 21 is separated from the central pipe 23, completing the releasing.

[0118] In the description of the present invention, it should be understood that the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "a plurality of" means two or more unless otherwise specifically defined.

[0119] In the present invention, unless otherwise clearly specified or limited, terms such as "installed", "connected", "coupled", "fixed", etc. shall be construed in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0120] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "examples", "specific examples", or "some examples", etc. means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0121] Finally, it should be noted that the above are only the preferred implementation schemes of the present invention and do not constitute any limitation to the present invention. Although the present invention has been described in detail with reference to the foregoing implementation schemes, for those skilled in the art, it is still possible to modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A plugging device, characterized in that, for plugging a sandblasting sliding sleeve, comprising: a central tube (23); an upper locking claw (214) sleeved outside the central tube (23), after the central tube (23) reaches the well position, the upper locking claw (214) axially abuts against the sandblasting sliding sleeve, so that the central tube (23) can move downward relative to the upper locking claw (214), and after the upper locking claw (214) axially moves relative to the central tube (23), it can radially expand and thus be anchored on the sandblasting sliding sleeve; an upper plugging mechanism (101) arranged on the outer wall of the central tube (23), after the upper locking claw (214) is anchored, the central tube (23) moves upward relative to the upper plugging mechanism (101), so that the upper plugging mechanism (101) radially expands to plug the sandblasting sliding sleeve; a lower plugging mechanism (102) arranged on the outer wall of the central tube (23), the lower plugging mechanism (102) is configured to radially expand to plug the sandblasting sliding sleeve; the upper plugging mechanism (101) and the lower plugging mechanism (102) are respectively arranged on the upper and lower sides of the sandblasting port of the sandblasting sliding sleeve.

2. The plugging device according to claim 1, characterized in that, a liner (213) is arranged between the upper locking claw (214) and the central tube (23), the upper end of the liner (213) axially abuts against the upper plugging mechanism (101), and mutually adapted ratchet teeth are arranged on the outer wall of the liner (213) and the inner wall of the upper locking claw (214).

3. The plugging device according to claim 1, characterized in that, the upper plugging mechanism (101) includes: a setting cylinder (24) sleeved on the central tube (23), the upper end of the setting cylinder (24) axially abuts against the central tube (23); a first rubber cylinder assembly (103) sleeved on the central tube (23), the upper end of the first rubber cylinder assembly (103) axially abuts against the lower end of the setting cylinder (24); a push cylinder (29) fixedly arranged on the central tube (23), the upper end of the push cylinder (29) abuts against the lower end of the first rubber cylinder assembly (103).

4. The plugging device according to claim 3, characterized in that, the first rubber cylinder assembly (103) includes: a middle rubber cylinder (28); end rubber cylinders (27) arranged at both axial ends of the middle rubber cylinder (28); and an outer protection bowl (25) and an inner protection bowl (26) arranged at the end of the end rubber cylinder (27) far from the middle rubber cylinder (28).

5. The plugging device according to claim 3, characterized in that, a movable block (210) is arranged between the push cylinder (29) and the central tube (23), and the central tube (23) pushes the push cylinder (29) to move upward through the movable block (210).

6. The plugging device according to claim 1, characterized in that, the lower plugging mechanism (102) is configured to radially expand after contacting with the liquid in the wellbore, so as to plug the sandblasting sliding sleeve.

7. The plugging device according to claim 6, characterized in that, The lower plugging mechanism (102) includes: Expanding middle glue (223); Expanding end glue (221) arranged at both axial ends of the expanding middle glue (223); And an inner expanding ring (220) and an outer expanding ring (219) arranged at one end of the expanding end glue (221) away from the expanding middle glue (223); After the expanding middle glue (223) and the expanding end glue (221) contact the liquid in the wellbore, they automatically expand.

8. The plug according to claim 7, Characterized in that, A spacer ring (222) is arranged between the expanding end glue (221) and the expanding middle glue (223).

9. The plug according to any one of claims 1 to 8, Characterized in that, A lower locking claw (225) is arranged outside the central tube (23). The upper end of the lower locking claw (225) is axially abutted against the lower plugging mechanism (102). When the central tube (23) moves relative to the lower locking claw (225), the lower locking claw (225) can be radially expanded, so that the lower locking claw (225) is anchored on the sandblasting sliding sleeve.

10. The plug according to claim 9, Characterized in that, A guiding cone (226) is arranged at the lower end of the central tube (23), The lower end of the guiding cone (226) is set to be conical, playing a guiding role, The outer wall of the guiding cone (226) close to the lower locking claw (225) is set to be conical. When the central tube (23) drives the guiding cone (226) to move upward, the guiding cone (226) can radially expand the lower locking claw (225).

11. A plugging method, Characterized in that, The plug according to any one of claims 1 to 10 is used for plugging.

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