Underground blowout prevention tool capable of being repeatedly set

Abstract

The invention discloses an underground blowout prevention tool capable of being repeatedly set, and belongs to the technical field of oil field oil extraction. Comprising a salvage mechanism and a sealing mechanism which are connected together in an inserted mode, a salvage claw A, a piston A and a piston B of the salvage mechanism are inserted into the sealing mechanism, the salvage claw A extends into a clamping claw, the clamping claw is in butt joint with a middle working barrel and the salvage claw A under the thrust action of a spring C, and the downhole blowout prevention tool capable of being repeatedly set is formed. The tool is placed at the lowermost end of a producing well or water injection well pipe column, and a plugging pipe column does not need to be independently delivered; the sealing piece is made of imported rubber materials and can bear the casing pressure of 25 MPa and resist the temperature of 120 degrees, the pressure bearing end of the sealing piece is provided with an expanding type sealing mechanism, and along with increase of pressure difference after tool setting, the better sealing is achieved, and the tighter the anchor fluke is achieved. When the tool goes down a well, well killing operation can be avoided, well killing procedures are saved, and construction cost is saved; when the tool is tripped into a pipe column in a well at a time, repeated setting and unsetting can be achieved, the blocking position of a packer can be changed at will, and releasing and fishing operation can be achieved at the same time.

Description

Technical Field

[0001] The invention belongs to the technical field of oil field production, and particularly relates to a downhole blowout prevention tool that can be repeatedly sealed. Background Art

[0002] At present, conventional downhole blowout prevention operations in oil fields are mostly to throw plugs into the oil pipe to block the oil pipe, or use bridge plugs to block the casing, or use well-killing hydraulic wells to complete downhole blowout prevention operations. Throwing plugs into the oil pipe Due to the long-term production of oil and water wells, wax or scale is deposited on the inner wall of the oil pipe, causing the thrown plugs to sometimes fail to reach the predetermined position and the casing is not blocked at this time, posing the risk of wellhead loss of control. When using bridge plugs for plugging, they are lost after being set, and it is often necessary to use a separate fishing tool to retrieve the bridge plug. After the bridge plug is unsealed, it is time-consuming and laborious to bring the bridge plug out of the wellhead without repeating the work. Using well-killing sub-well operations requires a large amount of well-killing fluid, vehicles, and a long preparation time. The biggest problem is that it will bring different degrees of formation pollution, affecting the production of oil wells or the injection volume of water wells. Summary of the invention

[0003] In view of the deficiencies in the prior art, an object of the present invention is to provide a downhole blowout prevention tool that can be repeatedly set and sealed.

[0004] The technical solution adopted by the invention is: a downhole blowout prevention tool that can be repeatedly sealed, and its technical key points are that it includes a plug-in connected salvage mechanism and a sealing mechanism, the salvage mechanism includes an upper joint, an upper center tube threadedly connected to the upper center tube, an upper pressure cap at the end of the upper center tube connected to the upper center tube by a thread, a ball seat and a steel ball are arranged in the upper center tube, a spring is arranged between the upper pressure cap, the ball seat and the steel ball, a leather cup is fixed to the outside of the upper center tube by a shear nail A, the leather cup seat is sleeved on the upper center tube, a piston A is threadedly connected to the upper center tube, a spring B is arranged between the leather cup seat and the piston A, a locking block fixes the fishing claw A to the center tube through a square hole on the fishing claw A, the piston B is inserted into the center tube and fixed to the fishing claw A by the shear nail B, and the shear nail C is fixed to the fishing claw A by a threaded hole; after the positioning sleeve is inserted into the center tube, the conical cap is threadedly connected to the center tube to form a salvage mechanism; The sealing mechanism includes an upper working cylinder, which is threadedly connected to the middle working cylinder, and a claw, a spring C and a protective sleeve are sequentially sleeved in the middle working cylinder. The top of the valve stem A sleeved on the valve body is connected to the valve body cap by a thread, and the tail is sleeved with a spring D. The valve plug threadedly connected to the valve body fixes the valve stem A in the valve body, and the main body is connected to the valve body by a thread. The anchor claw is assembled on the corresponding hole position on the main body. The pressure plate located on the top of the anchor claw fixes the spring E in the anchor claw, and the pressure plate is fixed to the main body by a hexagon socket screw; one end of the lower center tube is inserted into the main body and threadedly connected to the main body, the sleeve sleeved outside the main body is threadedly connected to the main body, the vulcanized rubber cylinder sleeved into the lower center tube is threadedly connected to the main body, the sleeve is connected to the lower joint by a thread, and the lower joint is threadedly connected to the main body and the lower center tube.

[0005] In the above scheme, the fishing claw A, piston A and piston B of the fishing mechanism are inserted into the sealing mechanism, wherein the fishing claw A extends into the clamping claw, and the clamping claw is connected with the middle working cylinder and the fishing claw A under the thrust of the spring C to form a repeatable downhole blowout prevention tool.

[0006] In the above scheme, the sealing process is as follows: pressurizing the casing annulus, the leather cup and the casing fit together to form a piston moving downward, the cut shear pin A moves downward together with the leather cup seat, the first liquid inlet hole on the leather cup coincides with the second liquid inlet hole on the upper center tube, the pressure is transmitted downward, and through the third liquid inlet hole on the conical cap, the valve stem A is pushed to compress the spring D and the valve stem cap downward, the pressure continues to be transmitted downward through the fourth liquid inlet hole on the valve body, the vulcanized rubber cylinder expands under the action of pressure and fits against the inner wall of the casing to form a seal, the anchor claws also extend outward and are firmly stuck on the inner wall of the casing, and then the pressure is removed, the valve stem A is quickly reset under the action of the energy storage of the spring D to form a seal with the valve body, and the pressure is locked in the sealing mechanism.

[0007] The beneficial effects of the present invention are as follows: the downhole blowout prevention tool that can be repeatedly sealed includes a plug-in connected fishing mechanism and a sealing mechanism, wherein the fishing claw A, piston A, and piston B of the fishing mechanism are inserted into the sealing mechanism, wherein the fishing claw A extends into the clamping claw, and the clamping claw completes docking with the middle working cylinder and the fishing claw A under the thrust of the spring C, thereby forming a downhole blowout prevention tool that can be repeatedly sealed.

[0008] The tool is placed at the bottom of the tubing string of the oil production well or water injection well, and there is no need to send the plugging tubing string separately; the sealing material uses imported rubber, which can withstand a casing pressure of 25MPa and a temperature resistance of 120°. The pressure-bearing end is equipped with an expansion sealing mechanism. After the tool is sealed, as the pressure difference increases, the seal becomes better and the anchor claws become tighter; the tool can be lowered into the well without well killing, saving the well killing process and construction costs; the tool can be repeatedly sealed and unsealed after being lowered into the tubing string once, and the plugging position of the packer can be changed arbitrarily, and the release and salvage operations can be realized at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0010] Figure 1 It is an assembly diagram of a downhole blowout prevention tool that can be repeatedly set in an embodiment of the present invention; Figure 2 for Figure 1 A partial enlarged schematic diagram of Figure 3It is a schematic diagram of the structure of the salvage mechanism in an embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of the blocking mechanism in an embodiment of the present invention; Figure 5 for Figure 4 A partial enlarged picture of the head; Figure 6 for Figure 4 A partial enlarged view of the tail; The serial numbers in the figure are as follows: 1 fishing mechanism, 1-1 upper joint, 1-2 upper gland, 1-3 spring, 1-4 ball and ball seat, 1-5 shear pin A, 1-6 leather cup, 1-7 upper center tube, 1-8 leather cup seat, 1-9 spring B, 1-10 piston A, 1-11 center tube, 1-12 fishing claw A, 1-13 locking block, 1-14 shear pin B, 1-15 piston B, 1-16 shear pin C, 1-17 positioning sleeve, 1-18 conical cap, 2 Sealing mechanism, 2-1 upper working cylinder, 2-2 middle working cylinder, 2-3 claw, 2-4 spring C, 2-5 protective sleeve, 2-6 valve body cap, 2-7 valve stem A, 2-8 spring D, 2-9 valve plug, 2-10 valve body, 2-11 main body, 2-12 baffle, 2-13 hexagon socket head screw, 2-14 spring E, 2-15 anchor claw, 2-16 lower center tube, 2-17 sleeve, 2-18 vulcanized rubber cylinder, 2-19 lower joint, 3 first liquid inlet hole, 4 second liquid inlet hole, 5 third liquid inlet hole, 6 fourth liquid inlet hole. DETAILED DESCRIPTION

[0011] To make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the following is a brief description of the present invention in conjunction with the attached Figure 1-Figure 6 The present invention is further described in detail with reference to the accompanying drawings and specific embodiments.

[0012] The repeatable downhole blowout prevention tool used in this embodiment includes a fishing mechanism 1 and a sealing mechanism 2, wherein the fishing mechanism includes an upper joint 1-1, an upper pressure cover 1-2, a spring 1-3, a ball and a ball seat 1-4, a shear pin A 1-5, a leather cup 1-6, an upper center pipe 1-7, a leather cup seat 1-8, a spring B 1-9, a piston A 1-10, a center pipe 1-11, a fishing claw A 1-12, a locking block 1-13, a shear pin B 1-14, a piston B 1-15, a shear pin C 1-16, a positioning sleeve 1-17 and a conical cap 1-18.

[0013] The third liquid inlet hole 5 is processed on the conical cap 1-18 of this embodiment. First, the ball seat, the steel ball 1-4 and the spring 1-3 are placed in the upper center tube 1-7 in sequence, and the upper pressure cover 1-2 is connected to the upper center tube 1-7 through threads. The upper joint 1-1 is threadedly connected to the upper center tube 1-7, the leather cup 1-6 is fixed to the upper center tube 1-7 by the shear nail A 1-5, the leather cup seat 1-8 and the spring B1-9 are sleeved on the outer side of the upper center tube 1-7 in sequence, the piston A 1-10 is threadedly connected to the upper center tube 1-7, the leather cup seat 1-8 and the spring B 1-9 are fixed to the upper center tube 1-7, the locking block 1-13 fixes the claw A 1-12 to the center tube 1-11 through the square hole on the claw A 1-12, the piston B1-15 is sleeved on the outer side of the center tube 1-11 and fixed to the claw A 1-12 by the shear nail B1-14, and the shear nail C1-16 is fixed to the claw A 1-12 through the threaded hole. After the positioning sleeve 1-17 is sleeved into the center tube 1-11, the conical cap 1-18 is threadedly connected to the center tube 1-11 to form a fishing mechanism.

[0014] The sealing mechanism structure in this embodiment includes: an upper working cylinder 2-1, a middle working cylinder 2-2, a claw 2-3, a spring C 2-4, a protective sleeve 2-5, a valve body cap 2-6, a valve stem A 2-7, a spring D 2-8, a valve plug 2-9, a valve body 2-10, a main body 2-11, a baffle 2-12, a hexagon socket head screw 2-13, a spring E 2-14, an anchor claw 2-15, a lower center tube 2-16, a sleeve 2-17, a vulcanized rubber cylinder 2-18, and a lower joint 2-19.

[0015] The upper working cylinder 2-1 is threadedly connected to the middle working cylinder 2-2, and the claw 2-3, spring C 2-4, and protective sleeve 2-5 are sequentially inserted into the middle working cylinder 2-2. The valve stem A 2-7 is inserted into the valve body 2-10, and its top is connected to the valve body cap 2-6 through a thread, and the tail is inserted into the spring D2-8. The valve plug 2-9 is threadedly connected to the valve body 2-10 to fix the valve stem A2-7 in the valve body 2-10. The main body 2-11 is connected to the valve body 2-10 through a thread, and the anchor claw 2-15 is placed in the corresponding hole on the main body 2-11. The baffle 2-12 fixes the spring E2-14 in the anchor claw 2-15, and the hexagon socket screw 2-13 fixes the baffle 2-12 on the main body 2-11. The lower center tube 2-16 is threadedly connected to the main body 2-11, the sleeve 2-17 is threadedly connected to the main body 2-11, the lower center tube 2-16 is inserted into the vulcanized rubber cylinder 2-18, and the vulcanized rubber cylinder 2-18 is threadedly connected to the main body 2-11. The sleeve is connected to the lower joint 2-19 through a thread, and the lower joint 2-19 is threadedly connected to the main body 2-11 and the lower center tube 2-16.

[0016] The fishing claw A 1-12, piston A 1-10 and piston B 1-15 of the fishing mechanism are inserted into the sealing mechanism, wherein the fishing claw A 1-12 extends into the clamping claw 2-3, and the clamping claw 2-3 is connected with the middle working cylinder 2-2 and the fishing claw A 1-12 under the thrust of the spring C 2-4 to form a downhole blowout prevention tool that can be repeatedly sealed.

[0017] Working principle and features of the downhole blowout prevention tool that can be repeatedly set in this embodiment: Sealing process: The casing annulus is pressurized, and the piston moves downward due to the tight fit between the leather cup 1-6 and the inner wall of the casing. The shear pin A1-5 then moves downward together with the leather cup seat 1-8. The first liquid inlet hole 3 on the leather cup 1-6 coincides with the second liquid inlet hole 4 on the upper center tube 1-7, and the pressure is transmitted downward. Through the third liquid inlet hole 5 on the conical cap 1-18, the valve stem A 2-7 is pushed downward to compress the spring D 2-8 and the valve stem cap 2-6. The pressure continues to be transmitted downward through the fourth liquid inlet hole 6 on the valve body 2-10. Under the action of pressure, the vulcanized rubber cylinder 2-18 expands and fits tightly with the inner wall of the casing to form a seal, and the anchor claw 2-15 also extends outward and is firmly stuck on the inner wall of the casing. Then the pressure is removed, and the valve stem A 2-7 is quickly reset under the energy storage of the spring D 2-8 to form a seal with the valve body 2-10, locking the pressure in the sealing mechanism.

[0018] Release process: The pressure cuts the shear pin B 1-15 upward through the third liquid inlet hole 5 on the conical cap 1-18, pushing the piston B1-15 upward. At this time, the lock block 1-13 loses its protection and is in a free rotation state, and the locking mechanism is opened. The pipe column is lifted up to cut the shear pin C1-16, and the claw A 1-12 moves downward. The claw A 1-12 is a petal structure that contracts inward and disengages from the clamping claw 2-3 to complete the release.

[0019] Unsealing process: The claw A 1-12, piston A 1-10, and piston B 1-15 of the lowered tubing fishing mechanism are inserted into the sealing mechanism, wherein the claw A 1-12 extends into the clamping claw 2-3, and the clamping claw 2-3 is connected and locked with the middle working cylinder 2-2 and the claw A 1-12 under the thrust of the spring C 2-4. The conical cap 1-18 is pressed down continuously to push the valve stem cap 2-6 downward, and the pressure locked in the sealing mechanism is released from the fourth liquid inlet hole 6 on the valve body 2-10. Then the anchor claw 2-15 is retracted into the main body 2-11 under the push of the spring E2-14, and the vulcanized rubber cylinder 2-18 is restored to its original state, and the entire tool is restored to the downhole state.

[0020] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A downhole blowout prevention tool that can be repeatedly set, characterized in that: It includes a plug-in salvaging mechanism and a sealing mechanism, the salvaging mechanism includes an upper joint, an upper center tube threadedly connected to the upper center tube, an upper pressure cap at the end of the upper center tube connected to the upper center tube by threads, a ball seat and a steel ball are arranged in the upper center tube, a spring is arranged between the upper pressure cap, the ball seat and the steel ball, a leather cup is fixed to the outside of the upper center tube by a shear nail A, the leather cup seat is sleeved on the upper center tube, the piston is threadedly connected to the upper center tube, a spring B is arranged between the leather cup seat and the piston, a locking block fixes the fishing claw to the center tube through a square hole on the fishing claw, the piston is sleeved into the center tube and fixed to the fishing claw by shear nails, and the shear nails are fixed to the fishing claw A through threaded holes; after the positioning sleeve is sleeved into the center tube, the conical cap is threadedly connected to the center tube to form a salvaging mechanism; The sealing mechanism includes an upper working cylinder, which is threadedly connected to the middle working cylinder, and a claw, a spring and a protective sleeve are sequentially sleeved in the middle working cylinder. The top of the valve stem sleeved on the valve body is threadedly connected to the valve body cap, and the tail is sleeved with a spring. The valve plug threadedly connected to the valve body fixes the valve stem in the valve body, and the main body is connected to the valve body through threads. The anchor claw is assembled on the corresponding hole position on the main body, and the pressure plate located on the top of the anchor claw fixes the spring in the anchor claw, and the pressure plate is fixed to the main body through a hexagon socket screw; one end of the lower center tube is inserted into the main body and threadedly connected to the main body, the sleeve sleeved outside the main body is threadedly connected to the main body, the vulcanized rubber cylinder sleeved into the lower center tube is threadedly connected to the main body, the sleeve is connected to the lower joint through threads, and the lower joint is threadedly connected to the main body and the lower center tube.

2. A repeatable downhole blowout prevention tool as claimed in claim 1, characterized in that: The fishing claw, piston A and piston B of the fishing mechanism are inserted into the sealing mechanism, wherein the fishing claw A extends into the clamping claw, and the clamping claw is connected with the middle working cylinder and the fishing claw A under the thrust of the spring C to form a downhole blowout prevention tool that can be repeatedly sealed.

3. A repeatable downhole blowout prevention tool as claimed in claim 1, characterized in that: Sealing process: pressurize the casing annulus, the leather cup and the casing fit together to form a piston moving downward, the cut shear pins move downward together with the leather cup seat, the first liquid inlet hole on the leather cup coincides with the second liquid inlet hole on the upper center pipe, the pressure is transmitted downward, and through the third liquid inlet hole on the conical cap, the valve stem A is pushed to compress the spring D and the valve stem cap downward, the pressure continues to be transmitted downward through the fourth liquid inlet hole on the valve body, under the action of pressure, the vulcanized rubber cylinder expands and fits the inner wall of the casing to form a seal, the anchor claws also extend outward and are firmly stuck on the inner wall of the casing, and then the pressure is removed, the valve stem A is quickly reset under the action of the energy storage of the spring D to form a seal with the valve body, and the pressure is locked in the sealing mechanism.

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