Tubing plug capable of being opened again and application tubular column and use method thereof

Abstract

The invention discloses an oil pipe blanking plug capable of being opened again and an application pipe column and a using method thereof. The oil pipe blanking plug comprises an outer cylinder and further comprises a plug throwing device, and the plug throwing device can be clamped with the inner wall of the outer cylinder; the plugging device comprises an inner sleeve, a plugging body, a bearing body and a ball; the plug body is arranged in the inner sleeve, the ball is arranged above the plug body, and the lower end of the inner sleeve is connected with the bearing body. The use mode is simple, the outer cylinder part directly enters a well along with a fracturing pipe column, and when an oil pipe needs to be plugged, the plugging device part is directly put into the well from a well opening, and plugging of the oil pipe can be achieved; when the oil pipe liquid flow channel needs to be opened, the liquid flow channel in the oil pipe can be opened by directly pressurizing the interior of the oil pipe until the pressure suddenly drops. Meanwhile, the ball on the upper portion of the plug throwing device and the inner conical surface of the inner sleeve of the plug throwing device can form spherical sealing at the moment, and the function of fixing a valve of the oil well pump is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of oilfield mining equipment, in particular to an oil pipe plug which can be opened again and an application pipe column and a use method thereof. Background Art

[0002] At present, fracturing technology is the main means of increasing oil field production, and with the continuous deepening of shale oil development, its application scale is also expanding. After the fracturing process is completed, it is generally put into production by self-flowing. In the early stage, the high blowout pressure can obtain a good oil well production, but as the blowout time increases, the oil well pressure will gradually decrease. When the pressure drops to 5MPa~2MPa, the production will drop rapidly, resulting in a rapid decline in oil well production capacity, and the pressure diffusion at this time will also become slower and slower. It will take a long time before the blowout pressure drops to 0MPa, which seriously affects the oil well production capacity. At present, most practices are to use well killing fluid to kill the well when the pressure is lower than a certain value or when the production is seriously reduced. After the well is completed with pressure, the fracturing string in the well is pulled out, and then the pump is lowered and put into production. This approach cannot achieve rapid production, and according to statistics, more than 20% of the wells have a large reaction between the killing fluid and the formation, resulting in blockage of the oil wells, which seriously affects the oil well production. Therefore, on-site technicians have raised the question of how to achieve rapid pumping and production without performing well killing operations? This invention is developed to address this problem.

[0003] Publication (Announcement) No.: CN213980752U, discloses a ball-controlled plug that can be retrieved. The ball-controlled plug that can be retrieved includes a working cylinder, a sealing valve core, and a center rod; a stop structure is fixed on the sealing valve core, and is used to cooperate with the center rod in the axial direction when the center rod is lifted up by fishing, so that the center rod drives the sealing valve core to move upward; a locking ball groove is arranged on the inner side of the working cylinder wall, and a locking ball hole extending along the radial direction of the sealing valve core is arranged on the sealing valve core, and a locking ball for locking and cooperating with the locking ball groove is arranged in the locking ball hole; a locking ball retaining surface for retaining the locking ball in the locking ball groove is arranged on the center rod, and a locking ball release position for staggering the locking ball retaining surface and the locking ball during the movement stroke of the center rod for the locking ball to retract into the installation cavity. Because the locking ball rolls more flexibly and is not easy to get stuck, the locking and unlocking performance is reliable, maintenance is convenient, and it can be used repeatedly, which solves the technical problem that the current plug adopts a slider, which easily leads to the unlocking and salvage failure of the plug, thereby reducing the oil and gas production efficiency.

[0004] After the prior art is completed, the oil pipe channel is completely opened, so the oil pump on the upper part of the pipe string is equivalent to lacking a fixed valve, which will inevitably affect the pumping efficiency of the oil pump and is not conducive to later production.

[0005] Publication (Announcement) No.: CN219932115U, discloses a plug for stratified testing of oilfield water injection wells, which includes an outer shell and an inner core. The outer shell is a hollow tube, including a cam seat, the cam seat is connected to an outer sleeve, the outer sleeve is connected to a pressure cap, the outer sleeve is provided with a water nozzle, the pressure cap is provided with a water inlet, and the cam seat is provided with an adjustment head seat; the inner core is inserted into the outer shell, including a fishing rod, the fishing rod is inserted into the adjustment head seat downward, the fishing rod head is provided with an adjustment hexagon, a cam is provided in the cam seat, a connecting rod passes through the cam, the fishing rod is connected to the top of the connecting rod, and the water nozzle column is connected to the bottom of the connecting rod. The utility model provides a plug for stratified testing of oilfield water injection wells, the fishing rod has high strength and is not easy to be damaged, only one water nozzle is provided to facilitate the measurement of water output, the device direction is fixed, and the plug and water distributor are prevented from being damaged, the operation is convenient, and the economic benefit is high.

[0006] The application scope of the prior art is water injection wells, and when the oil pipe is blocked and the liquid passage inside the oil pipe needs to be reopened, a fishing rod needs to be used for fishing, so it is greatly different from the present invention.

[0007] Publication (announcement) number: CN218816301U, discloses a downhole hydraulic circulation tool, including an adjusting sleeve outer tube, the upper end of the adjusting sleeve outer tube is connected to the upper joint, and the lower end of the adjusting sleeve outer tube is connected to the valve seat working tube; the adjusting sleeve outer tube is provided with an adjusting sleeve inside, the bottom wall of the adjusting sleeve is penetrated with a valve stem, the head end of the valve stem is connected to the valve seat arranged in the valve seat working tube, and a spring is sleeved on the rod body of the valve stem; a shear pin mounting hole is formed on the side wall of the valve seat working tube, and a shear pin is embedded in the shear pin mounting hole, and the end of the shear pin extends out of the shear pin mounting hole and is embedded in the prefabricated hole of the outer wall of the valve seat. The utility model solves the problem that it is impossible to smash open a conventional oil drain valve or it is difficult to fish out a production plug to establish a circulation channel in a highly deviated well or horizontal well. The application tool positively pressurizes the oil pipe, cuts the shear pin, and establishes a circulation channel to ensure smooth circulation and well washing in the well repair operation.

[0008] After the prior art is completed, the valve stem enters the bottom of the well, and the oil pipe channel is completely opened. In this way, the oil pump on the upper part of the pipe string is equivalent to lacking a fixed valve, which will inevitably affect the pumping efficiency of the oil pump and is not conducive to later production.

[0009] In summary, the technical solutions of the above-disclosed technologies, the technical problems to be solved, and the beneficial effects produced are all different from the present invention. Regarding more technical features, technical problems to be solved, and beneficial effects of the present invention, the above-disclosed technical documents do not provide any technical inspiration. Summary of the invention

[0010] In view of the above-mentioned defects in the prior art, the purpose of the present invention is to provide a re-openable oil pipe plug, its application pipe column and use method. The plug is simple to use, can achieve the plugging of the oil pipe, and can reopen the oil pipe liquid flow channel when plugging is not needed. After opening, it serves as a fixed valve in the pipe column.

[0011] In order to achieve the above object, the present invention adopts the following technical solutions:

[0012] A re-openable oil pipe plugger comprises an outer tube and a plugging device, wherein the plugging device can engage with the inner wall of the outer tube; the plugging device comprises an inner sleeve, a plugging body, a receiving body, and a ball; the plugging body is arranged in the inner sleeve, the ball is arranged above the plugging body, and the lower end of the inner sleeve is connected to the receiving body.

[0013] Furthermore, the blocking body includes a locking block seat, a locking block, a core shaft, and a shear nail;

[0014] Specifically, the locking block seat is provided with a shear nail hole, and the outer side of the core shaft is provided with a shear nail groove, and the shear nail penetrates into the shear nail hole of the locking block seat and the shear nail groove of the core shaft to fix the locking block seat and the core shaft together;

[0015] Specifically, the locking block seat is provided with a through hole above the shear nail hole, the locking block is arranged in the through hole and can slide freely in the through hole, and the core shaft seals the inner end of the through hole;

[0016] Specifically, the locking block seat is provided with a communicating hole above the through hole;

[0017] Specifically, the ball is located above the locking block seat.

[0018] Furthermore, the inner sleeve is provided with at least two circular holes on the tube wall below the plugging body;

[0019] Specifically, a concave ring is provided on the inner wall of the inner sleeve, and the locking block extends out of the through hole of the locking block seat and is inserted into the concave ring of the inner sleeve, so that the locking block seat and the inner sleeve are connected together;

[0020] Specifically, the outer wall of the locking block seat is in contact with the inner wall of the inner sleeve;

[0021] Specifically, the outer wall of the upper end of the inner sleeve is provided with an outer conical surface, and the inner wall is provided with a ball seat conical surface.

[0022] Furthermore, at least two of the locking blocks, through holes, and connecting holes are provided, and the number of the locking blocks is the same as the number of the through holes.

[0023] Furthermore, plugging device "O" rings are provided on the outer wall of the inner sleeve, between the locking block seat and the inner sleeve, and between the core shaft and the locking block seat for sealing.

[0024] Furthermore, the center of the receiving body is through-connected, and the side wall of the receiving body is symmetrically provided with two long grooves;

[0025] Specifically, the receiving body is provided with a radial through hole, the radial through hole is perpendicular to the two long slots in radial direction, and the radial through hole corresponds to the lower end of the long slot;

[0026] Specifically, positioning blocks are provided in the two long slots, and the positioning blocks are composed of a left positioning block and a right positioning block, and the left positioning block and the right positioning block are both provided with a limiting hole and a torsion spring engaging groove at the inner end;

[0027] Specifically, the two torsion arms of the torsion spring are respectively matched with the torsion spring engaging groove of the left positioning block and the torsion spring engaging groove of the right positioning block;

[0028] Specifically, a short shaft is arranged in the radial through hole of the receiving body, and the short shaft passes through the limiting hole of the left positioning block, the center hole of the torsion spring, and the limiting hole of the right positioning block to assemble the left positioning block, the right positioning block, and the torsion spring together.

[0029] Furthermore, the left positioning block and the right positioning block are both provided with sharp corners at the outer ends;

[0030] Specifically, the maximum radial distance between the sharp corners of the left positioning block and the right positioning block is greater than the inner diameter of the oil pipe.

[0031] Further, the outer tube comprises an upper joint, a sealing sleeve, a sleeve and a lower joint which are connected in sequence;

[0032] Specifically, the sealing sleeve is arranged in the upper joint and the sleeve, the lower joint is arranged in the sleeve, a convex ring is arranged on the inner wall of the upper joint, a wear-resistant ring is arranged between the lower end face of the convex ring and the upper end face of the sealing sleeve, and the wear-resistant ring is pressed against the lower end face of the convex ring of the upper joint by the sealing sleeve.

[0033] Furthermore, the sealing sleeve and the upper joint, the sealing sleeve and the sleeve, and the sleeve and the lower joint are all sealed by O-rings.

[0034] Furthermore, an inner conical surface is provided at the upper end of the inner wall of the wear-resistant ring, and the inner conical surface is used to fit with the outer conical surface;

[0035] Specifically, the inner diameter of the wear-resistant ring is the same as the inner diameter of the sealing sleeve, and the inner diameter of the wear-resistant ring and the inner diameter of the sealing sleeve are both smaller than the inner diameter of the oil pipe;

[0036] Specifically, an inner boss is provided at the upper end of the inner wall of the lower joint, and the inner boss is used to limit the upward movement of the positioning block.

[0037] In order to achieve the above object, the present invention adopts the following technical solutions:

[0038] An application pipe string of a re-openable oil pipe plug includes a casing, an upper oil pipe, a pump, and a lower oil pipe arranged in the casing, and also includes a re-openable oil pipe plug;

[0039] The re-openable oil pipe plugging device comprises an outer tube and a plugging device, wherein the plugging device can be engaged with the inner wall of the outer tube; the plugging device comprises an inner sleeve, a plugging body, a receiving body, and a ball; the plugging body is arranged in the inner sleeve, the ball is arranged above the plugging body, and the lower end of the inner sleeve is connected to the receiving body;

[0040] The outer tube of the re-openable oil pipe plug is directly connected to the lower end of the oil pump barrel, and the upper end of the lower oil pipe is connected to the lower end of the outer tube;

[0041] The lower part of the lower oil pipe is connected to a fracturing string to meet the fracturing process;

[0042] The lower end of the upper oil pipe is connected to the oil pump, and the upper end of the upper oil pipe is connected to the wellhead equipment.

[0043] In order to achieve the above object, the present invention adopts the following technical solutions:

[0044] A method for using a re-openable oil pipe plug includes the following steps:

[0045] S1. The outer cylinder is first lowered into the well along with the oil pipe. When the oil pipe needs to be plugged, the plugging device is put in from the wellhead;

[0046] S2. When the plugging device falls into the outer tube and is in place, the outer conical surface of the upper part of the inner sleeve contacts the inner conical surface of the upper part of the wear-resistant ring. At this time, the "O" ring outside the inner sleeve forms a seal with the inner wall of the sealing sleeve of the outer tube. At the same time, the positioning block cooperates with the inner boss of the lower joint of the outer tube, so that the plugging device cannot move upward.

[0047] S3. When it is necessary to reopen the liquid channel in the oil pipe, it is necessary to pressurize the inside of the oil pipe. At this time, the core shaft of the plugging device will be subjected to a downward piston force. When the piston force is greater than the shear force of the shear nails, the core shaft will move downward and fall to the upper part of the receiving body of the plugging device; at the same time, as the core shaft moves downward, the locking block is also released, and under the action of gravity, it will move downward with the locking block seat, and finally fall to the upper part of the receiving body; at this time, the ball moves downward, and will form a spherical seal with the inner conical surface of the upper part of the inner sleeve, playing the role of fixing the valve of the oil pump.

[0048] Compared with the prior art, the present invention has the following beneficial effects:

[0049] The present invention is simple to use. The outer tube part is directly put into the well with the fracturing string. When the oil pipe needs to be blocked, the plugging device part is directly put in from the wellhead to achieve the blocking of the oil pipe; when the oil pipe liquid flow channel needs to be opened, the oil pipe is directly pressurized until the pressure drops suddenly, so that the liquid flow channel inside the oil pipe can be opened. At the same time, the ball on the upper part of the plugging device and the inner conical surface of the inner sleeve of the plugging device can form a spherical seal at this time, which plays the role of fixing the valve of the oil pump. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 It is a structural schematic diagram of an outer cylinder of an oil pipe plug that can be opened again according to the present invention;

[0051] Figure 2 It is a structural schematic diagram of a plugging device for an oil pipe plugging device that can be opened again according to the present invention;

[0052] Figure 3 It is a structural schematic diagram of a re-openable oil pipe plug of the present invention;

[0053] Figure 4 It is a structural schematic diagram of an application pipe string of a re-openable oil pipe plugging device of the present invention;

[0054] In the figure: 1, upper joint; 2, wear-resistant ring; 3, "O" ring; 4, sealing sleeve; 5, sleeve; 6, lower joint; 7, ball; 8, locking block seat; 9, inner sleeve; 10, plugging device "O" ring; 11, locking block; 12, core shaft; 13, shear nail; 14, receiving body; 15, torsion spring; 16, short shaft; 17, positioning block; 18, casing; 19, upper oil pipe; 20, pump barrel; 21, outer barrel; 22, lower oil pipe; 201, inner cone of wear-resistant ring; 601, inner boss; 901, cone of ball seat. DETAILED DESCRIPTION

[0055] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0056] Embodiment 1:

[0057] See also Figures 1 to 3 The present invention provides a re-openable oil pipe plug, comprising an outer tube and a plugging device;

[0058] See also Figure 1, is the outer tube part of the present invention, the outer tube includes an upper joint 1, a sealing sleeve 4, a sleeve 5 and a lower joint 6 connected in sequence; the sealing sleeve 4 is arranged in the upper joint 1 and the sleeve 5, the lower joint 6 is arranged in the sleeve 5, the upper joint 1 is provided with a convex ring on the inner wall, a wear-resistant ring 2 is arranged between the lower end surface of the convex ring and the upper end surface of the sealing sleeve 4, and the wear-resistant ring 2 is pressed against the lower end surface of the convex ring of the upper joint 1 by the sealing sleeve 4.

[0059] The sealing sleeve 4 and the upper joint 1 , the sealing sleeve 4 and the sleeve 5 , and the sleeve 5 and the lower joint 6 are sealed by means of an O-ring 3 .

[0060] See also Figure 1 , Figure 3 An inner conical surface 201 is provided at the upper end of the inner wall of the wear-resistant ring 2, and the inner diameter of the wear-resistant ring 2 is the same as the inner diameter of the sealing sleeve 4. The inner diameters of the wear-resistant ring 2 and the sealing sleeve 4 are both smaller than the inner diameter of the oil pipe. An inner boss 601 is provided at the upper end of the inner wall of the lower joint 6.

[0061] See also Figure 2 , is the plugging device part of the present invention, the plugging device comprises an inner sleeve 9, a plugging body, and a receiving body 14;

[0062] The blocking body is arranged in the inner sleeve 9, and the inner sleeve 9 is provided with at least two circular holes on the tube wall below the blocking body, and the circular holes can realize the communication between the internal and external liquids; the lower end of the inner sleeve 9 is connected to the receiving body 14 through a thread.

[0063] The blocking body includes a ball 7, a locking block seat 8, a locking block 11, a core shaft 12, and a shear nail 13;

[0064] The locking block seat 8 is provided with a shear nail hole, and the outer side of the core shaft 12 is provided with a shear nail groove. The shear nail 13 penetrates into the shear nail hole of the locking block seat 8 and the shear nail groove of the core shaft 12 to fix the locking block seat 8 and the core shaft 12 together; the locking block seat 8 is provided with a through hole above the shear nail hole, the locking block 11 is arranged in the through hole and can slide freely in the through hole, the core shaft 12 closes the inner end of the through hole, and the locking block seat 8 is provided with a connecting hole above the through hole, and the connecting hole can connect the internal and external liquids; the ball 7 is located above the locking block seat 8, can move freely, and is supported by the locking block seat 8.

[0065] The inner wall of the inner sleeve 9 is provided with a concave ring, and the locking block 11 extends out of the through hole of the locking block seat 8 and is inserted into the concave ring of the inner sleeve 9, connecting the locking block seat 8 and the inner sleeve 9 together, and the outer wall of the locking block seat 8 is in contact with the inner wall of the inner sleeve 9; the outer wall of the upper end of the inner sleeve 9 is provided with an outer conical surface, and the inner wall is provided with a ball seat conical surface 901.

[0066] At least two of the locking blocks 11, through holes, and connecting holes are provided, and the number of the locking blocks 11 is the same as the number of the through holes.

[0067] The center of the receiving body 14 is through-through, and two long grooves are symmetrically arranged on the side wall of the receiving body 14. The receiving body 14 is provided with a radial through hole, and the radial through hole is radially perpendicular to the two long grooves, and the radial through hole corresponds to the lower end of the long groove. Positioning blocks 17 are arranged in the two long grooves, and the positioning blocks 17 are composed of a left positioning block and a right positioning block. The left positioning block and the right positioning block are both provided with a limiting hole and a torsion spring engaging groove at the inner end, and the two torsion arms of the torsion spring 15 are respectively matched with the torsion spring engaging groove of the left positioning block and the torsion spring engaging groove of the right positioning block, and a short shaft 16 is arranged in the radial through hole of the receiving body 14, and the short shaft 16 passes through the limiting hole of the left positioning block, the center hole of the torsion spring 15, and the limiting hole of the right positioning block, and the left positioning block, the right positioning block, and the torsion spring 15 are assembled together; the torsion spring can position the two positioning blocks 17 at the bottom end of the long groove opened in the receiving body 14.

[0068] The left positioning block and the right positioning block are both provided with sharp corners at the outer ends. When the sharp corners of the positioning block 17 are subjected to an upward force, the torsion spring 15 can be twisted to achieve rotation around the center of the short shaft 16. When the force disappears, the positioning block 17 will return to its original state under the action of the torsion of the torsion spring 15. The radial distance between the sharp corners of the left positioning block and the right positioning block in the free state is greater than the inner diameter of the oil pipe.

[0069] The outer wall of the inner sleeve 9, between the locking block seat 8 and the inner sleeve 9, and between the core shaft 12 and the locking block seat 8 are all provided with plugging device "O" rings for sealing.

[0070] When the plugging device is put into the oil pipe, since the maximum outer diameter of the plugging device is smaller than the inner diameter of the oil pipe, and the positioning block 17 will automatically rotate upward if it encounters resistance, thereby reducing the radial distance, it will not hinder the plugging device from falling in the oil pipe;

[0071] When the plugging device falls into the outer cylinder, since the inner diameter of the wear-resistant ring 2 is smaller than the maximum outer diameter above the inner sleeve 9, the plugging device will not move downward any further; since the positioning block 17 is no longer subject to resistance at this time, it will restore to a free state under the action of the torsion spring 15. At the same time, due to the design of the inner boss 601 on the upper part of the lower joint, the plugging device will inevitably not move too far upward; at the same time, due to the cooperation between the "O" ring 10 on the outside of the plugging device and the sealing sleeve 4, the plugging function inside the oil pipe is realized.

[0072] When it is necessary to open the liquid flow channel of the oil pipe again, it is only necessary to increase the pressure on the oil pipe to the shearing pressure of the shear nail 13. At this time, the core shaft 12 is sheared along with the shear nail 13, and quickly descends. Then the locking block 11 is released, and the locking block seat 8 also moves downward under the dual action of liquid pressure and gravity until it falls above the receiving body 14; after the locking block seat 8 moves downward, the ball 7 forms a spherical seal with the inner conical surface of the upper part of the inner sleeve, thereby playing the role of fixing the valve of the pump barrel.

[0073] Embodiment 2:

[0074] See attached Figure 4 , is a specific embodiment of the present invention, an application string of a re-openable oil pipe plugger, comprising a casing 18, in which an upper oil pipe 19, a pump 20, and a lower oil pipe 22 are arranged, an outer tube 21 of a re-openable oil pipe plugger is directly connected to the lower end of the pump 20, the upper end of the lower oil pipe 22 is connected to the lower end of the outer tube 21, and the lower part of the lower oil pipe 22 can be connected to a corresponding fracturing string to meet the fracturing process, the lower end of the upper oil pipe 19 is connected to the pump 20, and the upper end of the upper oil pipe is connected to the wellhead equipment.

[0075] Embodiment 3:

[0076] Specific use of the present invention:

[0077] S1. The outer cylinder is first lowered into the well along with the oil pipe. When the oil pipe needs to be plugged, the plugging device is put in from the wellhead;

[0078] S2, when the plugging device falls into the outer tube and is in place (i.e., the outer conical surface of the upper part of the inner sleeve 9 contacts the inner conical surface 201 of the upper part of the wear-resistant ring 2), the "O" ring outside the inner sleeve forms a seal with the inner wall surface of the sealing sleeve 4 of the outer tube, and the positioning block 17 cooperates with the inner boss 601 of the lower joint 6 of the outer tube, so that the plugging device cannot move upward;

[0079] S3. After the plugging device falls into the outer cylinder and is in place, when it is necessary to reopen the liquid channel in the oil pipe, it is necessary to pressurize the inside of the oil pipe. At this time, the core shaft 12 of the plugging device will be subjected to a certain downward piston force. When the piston force is greater than the shearing force of the shear nail 13, the core shaft 12 will move downward and fall to the upper part of the receiving body 14 of the plugging device; at the same time, as the core shaft 12 moves downward, the locking block 11 is also released, and under the action of gravity, it will move downward with the locking block seat 8, and finally fall to the upper part of the receiving body 14; at this time, the ball 7 moves downward, and will form a spherical seal with the inner conical surface 901 on the upper part of the inner sleeve, playing the role of fixing the valve of the oil pump.

[0080] All components and connection methods of components not discussed in this application belong to the known technologies in this technical field and can be directly applied without further explanation.

[0081] In the present invention, the term "plurality" refers to two or more than two, unless otherwise clearly defined. The terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; "connected" can be a direct connection or an indirect connection through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0082] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by terms such as “upper”, “lower”, “left”, “right”, “front” and “back” are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or unit referred to must have a specific direction, be constructed and operated in a specific orientation, and therefore, cannot be understood as a limitation on the present invention.

[0083] In the description of this specification, the description of the terms "one embodiment", "some embodiments", "specific embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction 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 can be combined in any one or more embodiments or examples in a suitable manner.

[0084] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A re-openable oil pipe plug, comprising an outer tube, characterized in that: It also includes a plugging device, which can be engaged with the inner wall of the outer tube; The plugging device comprises an inner sleeve, a plugging body, a receiving body and a ball; The blocking body is arranged in the inner sleeve, the ball is arranged above the blocking body, and the lower end of the inner sleeve is connected to the receiving body.

2. A re-openable oil pipe plug according to claim 1, characterized in that: The blocking body comprises a locking block seat, a locking block, a core shaft and a shear nail; The locking block seat is provided with a shear nail hole, and the outer side of the core shaft is provided with a shear nail groove. The shear nail penetrates into the shear nail hole of the locking block seat and the shear nail groove of the core shaft to fix the locking block seat and the core shaft together; The locking block seat is provided with a through hole above the shear nail hole, the locking block is arranged in the through hole and can slide freely in the through hole, and the core shaft seals the inner end of the through hole; The locking block seat is provided with a communicating hole above the through hole; The ball is located above the locking block seat.

3. A re-openable oil pipe plug according to claim 2, characterized in that: The inner sleeve is provided with at least two circular holes on the pipe wall below the plugging body; The inner wall of the inner sleeve is provided with a concave ring, and the locking block extends out of the through hole of the locking block seat and is inserted into the concave ring of the inner sleeve, so that the locking block seat and the inner sleeve are connected together; The outer wall of the locking block seat is in contact with the inner wall of the inner sleeve; The outer wall of the upper end of the inner sleeve is provided with an outer conical surface, and the inner wall is provided with a ball seat conical surface.

4. A re-openable oil pipe plug according to claim 3, characterized in that: At least two of the locking blocks, through holes and connecting holes are provided, and the number of the locking blocks is the same as that of the through holes.

5. The re-openable oil pipe plug according to claim 3, characterized in that: The outer wall of the inner sleeve, between the locking block seat and the inner sleeve, and between the core shaft and the locking block seat are all provided with a plugging device "O" ring for sealing.

6. The re-openable oil pipe plug according to claim 3, characterized in that: The center of the receiving body is through-hole, and the side wall of the receiving body is symmetrically provided with two long grooves; The receiving body is provided with a radial through hole, the radial through hole is perpendicular to the two long slots in radial direction, and the radial through hole corresponds to the lower end of the long slot; Positioning blocks are arranged in the two long slots, and the positioning blocks are composed of a left positioning block and a right positioning block. The left positioning block and the right positioning block are both provided with a limiting hole and a torsion spring engaging groove at the inner end; The two torsion arms of the torsion spring are respectively matched with the torsion spring engaging groove of the left positioning block and the torsion spring engaging groove of the right positioning block; A short shaft is arranged in the radial through hole of the receiving body, and the short shaft passes through the limiting hole of the left positioning block, the central hole of the torsion spring, and the limiting hole of the right positioning block, so as to assemble the left positioning block, the right positioning block, and the torsion spring together.

7. The re-openable oil pipe plug according to claim 6, characterized in that: The left positioning block and the right positioning block are both provided with sharp corners at the outer ends; The maximum radial distance between the sharp corners of the left positioning block and the right positioning block is greater than the inner diameter of the oil pipe.

8. The re-openable oil pipe plug according to claim 6, characterized in that: The outer cylinder comprises an upper joint, a sealing sleeve, a sleeve and a lower joint which are connected in sequence; The sealing sleeve is arranged in the upper joint and the sleeve, the lower joint is arranged in the sleeve, a convex ring is arranged on the inner wall of the upper joint, a wear-resistant ring is arranged between the lower end face of the convex ring and the upper end face of the sealing sleeve, and the wear-resistant ring is pressed against the lower end face of the convex ring of the upper joint by the sealing sleeve.

9. The re-openable oil pipe plug according to claim 8, characterized in that: The sealing sleeve and the upper joint, the sealing sleeve and the sleeve, and the sleeve and the lower joint are all sealed by "O" rings.

10. The re-openable oil pipe plug according to claim 8, characterized in that: An inner conical surface is provided at the upper end of the inner wall of the wear-resistant ring, and the inner conical surface is used to fit with the outer conical surface; The inner diameter of the wear-resistant ring is the same as the inner diameter of the sealing sleeve, and both the inner diameter of the wear-resistant ring and the inner diameter of the sealing sleeve are smaller than the inner diameter of the oil pipe; An inner boss is provided at the upper end of the inner wall of the lower joint, and the inner boss is used to limit the positioning block from moving upward.

11. An application string of a re-openable oil pipe plug, comprising a casing, an upper oil pipe, a pump, and a lower oil pipe arranged in the casing, characterized in that: Also included is a re-openable oil pipe plug; The re-openable oil pipe plugging device comprises an outer tube and a plugging device, wherein the plugging device can be engaged with the inner wall of the outer tube; The plugging device comprises an inner sleeve, a plugging body, a receiving body and a ball; The blocking body is arranged in the inner sleeve, the ball is arranged above the blocking body, and the lower end of the inner sleeve is connected to the receiving body; The outer tube of the re-openable oil pipe plug is directly connected to the lower end of the oil pump barrel, and the upper end of the lower oil pipe is connected to the lower end of the outer tube; The lower part of the lower oil pipe is connected to a fracturing string to meet the fracturing process; The lower end of the upper oil pipe is connected to the oil pump, and the upper end of the upper oil pipe is connected to the wellhead equipment.

12. A method for using a re-openable oil pipe plug, characterized in that: The following steps are included: S1. The outer cylinder is first lowered into the well along with the oil pipe. When the oil pipe needs to be plugged, the plugging device is put in from the wellhead; S2. When the plugging device falls into the outer tube and is in place, the outer conical surface of the upper part of the inner sleeve contacts the inner conical surface of the upper part of the wear-resistant ring. At this time, the "O" ring outside the inner sleeve forms a seal with the inner wall of the sealing sleeve of the outer tube. At the same time, the positioning block cooperates with the inner boss of the lower joint of the outer tube, so that the plugging device cannot move upward. S3. When it is necessary to reopen the liquid channel in the oil pipe, it is necessary to pressurize the inside of the oil pipe. At this time, the core shaft of the plugging device will be subjected to a downward piston force. When the piston force is greater than the shear force of the shear nails, the core shaft will move downward and fall to the upper part of the receiving body of the plugging device; at the same time, as the core shaft moves downward, the locking block is also released, and under the action of gravity, it will move downward with the locking block seat, and finally fall to the upper part of the receiving body; at this time, the ball moves downward, and will form a spherical seal with the inner conical surface on the upper part of the inner sleeve, playing the role of fixing the valve of the oil pump.

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