A wire-powered cable fishing unit system and operation method

Abstract

The present invention discloses a wire-powered cable fishing unit system and an operation method, which includes a double-layer casing. A hydraulic control sliding sleeve, a deep well safety valve, a positioning seal and a perforated pipe are successively arranged below the inner casing. A tubing hanger, a lifting flange and a blowout preventer group are successively installed at the wellhead. The first end of the wire-powered cable is sequentially connected to a downhole suspended fishing head, a sealing cylinder, a telescopic pipe, a packer, a hydraulic anchor, a unit and a pump condition and enters the second casing. The second end of the wire-powered cable is connected to a cable winch. When the unit reaches a predetermined depth, the wire-powered cable is temporarily suspended at the wellhead. After the unit is stable, the wellhead suspension device is connected to a temporary lifting clamp. After the wire-powered cable is tightened, a large-diameter production tree is installed. The present invention does not require pulling out and running in the tubing, and there is no workover rig operation. The unit is quickly and conveniently pulled out and run in through the wire-powered cable, solving problems such as firmly pulling out and running in the unit under the connection of the wire-powered cable and effectively preventing the unit from rotating underground.

Description

Technical Field

[0001] The present invention belongs to the technical field of the offshore oil industry, and particularly relates to a wire-powered cable fishing unit system and an operation method thereof. Background Art

[0002] In the field of the offshore oil industry, after a conventional unit is lowered into the well, the upper end is connected by a tubing string. Through the combination of multiple tubing sections, the oil lifted by the unit is lifted to the wellhead to achieve crude oil production. During the above operation process, lowering the tubing is time-consuming and laborious. Moreover, when the unit fails and needs to be lifted out of the well, the tubing needs to be lifted out of the well step by step, which is costly and time-consuming. Summary of the Invention

[0003] The problem to be solved by the present invention is to provide a wire-powered cable fishing system and an operation method thereof. By using a wire-powered cable to lower and raise the unit, the original casing is made to function as a tubing string, and the operation process is efficient with low lowering and raising operation costs. The invention solves a series of problems such as how to prevent the unit from rotating in the well under the suspension of the wire-powered cable, how to connect large and small flat cables, how to seal after connection, wellhead suspension technology, and the fixation of the wire-powered cable to the unit.

[0004] To solve the above technical problems, the technical solution adopted by the present invention is as follows: A wire-powered cable fishing unit system includes a first casing, inside which a second casing is provided. The first casing and the second casing are coaxial. Below the second casing, a hydraulic sliding sleeve, a deep well safety valve, a positioning seal, and a perforated pipe are successively arranged. One end of a first hydraulic control pipeline is connected to the deep well safety valve, and the other end of the first hydraulic control pipeline is connected to the wellhead. One end of a second hydraulic control pipeline is connected to the hydraulic sliding sleeve, and the other end of the second hydraulic control pipeline is connected to the wellhead. The wellhead is successively provided with a tubing hanger, a lifting flange, and a blowout preventer group. The first end of the wire-powered cable passes through the tubing hanger, the lifting flange, and the blowout preventer group and then enters the second casing. The first end of the wire-powered cable is successively connected to a downhole suspended fishing head, a sealing cylinder, a telescopic pipe, a packer, a hydraulic anchor, a unit, and a pump working condition. The second end of the wire-powered cable is placed outside the wellhead and is connected to a cable winch. When the unit descends to a predetermined depth, the outside of the wire-powered cable is temporarily fixed at the wellhead. The wellhead temporary suspension is placed on the tubing hanger. After the unit is stable, the wire-powered cable is removed, and the outer steel wires of the wire-powered cable are connected to the wellhead suspension device. The wellhead suspension device is connected to a temporary lifting clamp. After the wire-powered cable is fully stressed and tightened, the wellhead temporary suspension is removed, the wellhead suspension device is placed on the tubing hanger, the temporary lifting clamp is removed, and a large-diameter production tree is installed. The wire-powered cable is of a multi-strand structure. A circle of thick steel wires is evenly distributed in a ring shape on the outside of the wire-powered cable. The diameter of the thick steel wires is 2 mm. Cable cores are evenly distributed in a ring shape at the center of the wire-powered cable. An insulating layer is provided between the thick steel wires and the cable cores. The wellhead temporary suspension includes a T-shaped pressing plate and a copper core sleeve. There are two groups of the T-shaped pressing plate and the copper core sleeve respectively. After the two groups of the T-shaped pressing plate and the copper core sleeve are fixed by bolts, they are symmetrically arranged left and right. A friction groove is provided inside the copper core sleeve. The copper core sleeve fixes the cable after being clamped by the bolts.

[0005] Further, the first casing is a 9-5 / 8-inch casing, and the second casing is a 5.5-inch casing.

[0006] Further, the second end of the wire-powered cable passes through a crown block and a traveling block and is connected to the cable winch. The crown block includes a connecting frame, on which a movable plate is provided. The wire-powered cable is embedded into the crown block through the movable plate. One end of the connecting frame is connected to the central shaft of the crown block, and the other end of the connecting frame is connected to a claw, which fixes the crown block on a platform work site stand or a hoisting mechanism. The structure of the traveling block is the same as that of the crown block.

[0007] Further, a cavity is provided inside the downhole suspension fishing head. Inside the cavity, a copper cone and a bolt group are successively arranged from top to bottom. The bolt group includes a main bolt cap and an anti-back-off bolt. The bolt group presses the copper cone, and the copper cone has two layers.

[0008] Further, the sealing cylinder is cylindrical. A through hole is provided on the central axis of the sealing cylinder. The sealing cylinder and the through hole are coaxial. The inside of the sealing cylinder is a cavity structure. Glue injection holes and observation holes are provided on the outer cylindrical surface of the sealing cylinder. The glue injection holes and the observation holes are both communicated with the cavity structure.

[0009] Further, the telescopic pipe includes a first telescopic pipe and a second telescopic pipe. A trapezoidal thread and a pin are provided at the connection between the first telescopic pipe and the second telescopic pipe. The trapezoidal thread connects the first telescopic pipe and the second telescopic pipe, and the pin fastens the first telescopic pipe and the second telescopic pipe.

[0010] Further, the outside of the hydraulic anchor is a claw structure. An expansion bladder is provided inside the hydraulic anchor. The expansion bladder is connected to the pump condition through a pressure pipeline, and the internal pressure is monitored through the pump condition.

[0011] Further, the present invention also provides an operation method for a wire-powered cable fishing unit system. Using the above-mentioned wire-powered cable fishing unit system, it includes the following steps:

[0012] S1: Remove the original conventional Christmas tree, install the blowout preventer group and conduct a pressure test.

[0013] S2: Lower a second casing into the wellhead. A deep well safety valve and a hydraulic control sliding sleeve are attached to the bottom of the second casing. One end of the first hydraulic control pipeline and the second hydraulic control pipeline are respectively connected to the deep well safety valve and the hydraulic control sliding sleeve, and the other ends of the first hydraulic control pipeline and the second hydraulic control pipeline are both connected to the wellhead.

[0014] S3: Close the deep well safety valve and the hydraulic control sliding sleeve, and remove the blowout preventer group.

[0015] S4: Install the tubing hanger and the lifting flange.

[0016] S5: Install the blowout preventer group again and conduct a pressure test.

[0017] S6: Connect the unit and the pump condition.

[0018] S7: Connect a hydraulic anchor, a packer, a telescopic pipe, and a downhole suspension fishing head in sequence above the unit. The hydraulic anchor is connected to the pump condition through a hydraulic control pipeline.

[0019] S8: Fix the crown block and the traveling block on the derrick, and use a cable winch to drive the wire-powered cable to lower the unit and the tool string.

[0020] S9: When reaching the expected depth, apply pressure to the hydraulic anchor.

[0021] S10: At the wellhead position, tightly fix the temporary wellhead suspension outside the wire power cable, start the cable winch, and place the temporary wellhead suspension on the tubing hanger.

[0022] S11: Cut off the wire power cable, remove the crown block and the traveling block, and connect the end of the wire power cable to the wellhead suspension device and the temporary elevator.

[0023] S12: Lift the wellhead suspension device and the temporary elevator, and straighten the wire power cable.

[0024] S13: Remove the temporary wellhead suspension, slowly place the wellhead suspension device on the wellhead tubing hanger, and after it is stably placed, remove the temporary elevator.

[0025] S14: Install a large-bore production tree at the wellhead, connect the cable core to the power cable used on the ground, pass the power cable through the cable penetrator on the large-bore production tree, lead out the wire power cable fishing system, and connect it to the ground electrical equipment.

[0026] The advantages and positive effects of the present invention are as follows:

[0027] 1. The structure of the present invention is simple and the operation is convenient. By designing a series of special tools and operation processes, a series of problems are solved, such as how to prevent the unit from rotating in the well under the suspension of the wire power cable, how to connect the large-flat and small-flat cables, how to seal after connection, the wellhead suspension process, and the fixation of the wire power cable to the unit.

[0028] 2. The first casing size of the present invention is 9 5 / 8-inch casing, and the second casing with a size of 5.5 inches is run inside it. A double-layer casing is adopted. The upper and lower spaces of the 5.5-inch casing are separated by a packer, and the unit is anchored by a hydraulic anchor. The upper half of the 5.5-inch casing serves as the tubing. When the unit operates, there is no need to run the tubing, the process is simple and the operation is convenient. At the same time, the operation cost is reduced.

[0029] 3. A hydraulic control sliding sleeve and a deep well safety valve are sequentially connected below the two layers of casing of the present invention. One end of the second hydraulic control pipeline is connected to the hydraulic control sliding sleeve, and the other end is connected to the wellhead, ensuring that after the packer is activated, chemical agent injection, well killing, and well flushing operations can be carried out through the hydraulic control sliding sleeve. One end of the first hydraulic control pipeline is connected to the deep well safety valve, and the other end is connected to the wellhead. The deep well safety valve prevents well blowout in the well. When the pressure of the safety valve is abnormal, the pressure of the deep well safety valve is monitored through the hydraulic control pipeline connected to the wellhead, and the safety performance is strong.

[0030] 4. The present invention improves the installation operation space of the wellhead suspension device and the cable connection by arranging a lifting flange at the wellhead; arranges a blowout preventer group at the wellhead when lowering and fishing the unit to avoid the risk of blowout; increases the operation space and operation distance at the wellhead position through the crown block and the ground pulley. The pulley block is fixed on the platform work site bench or the hoisting mechanism through a claw. A trap door is opened beside the pulley block to facilitate the wire power cable to be embedded into the pulley from the side, which is convenient and efficient; through a customized large-diameter Christmas tree, when the subsequent unit fails and needs to be lifted out of the well, the unit can directly pass through the Christmas tree through the wire power cable. When lowering the well, the unit can directly pass through the Christmas tree and enter the well. There is no need to remove the Christmas tree when hoisting and lowering the unit, which saves time and effort.

[0031] 5. The cable winch of the present invention is equipped with a tension display instrument. When hoisting and lowering the unit through the wire power cable, if it is found that the unit gets stuck or accelerates and falls into the well, and when the tension display exceeds the maximum tension that the wire power cable can withstand, the operation is stopped in time or the operation process is adjusted, with a high safety factor.

[0032] 6. The top of the downhole suspension fishing head of the present invention is made in the size and style of the fishing head, which is convenient for fishing operations after accidentally falling into the well. Inside, two circles of copper cones are pressed tightly by a bolt group. After the outer steel wires of the wire power cable are peeled off, the outer steel wires of the wire power cable are pressed tightly, or 316 stainless steel cones are pressed tightly by a bolt group to press tightly the outer steel wires of the wire power cable. Through the pressing force of the stainless steel buckle and the principle of similar solubility of metals, the steel wires are fastened with strong firmness.

[0033] 7. For the voltage resistance and insulation sealing of the connection of the large and small flat cables of the present invention, a glue filling hole and an observation hole are opened above the sealing cylinder. After the large and small flat cables are connected, glue is filled through the glue filling hole. When it is seen that the sealing glue emerges from the observation hole, the glue filling is stopped and the sealing glue is waited to solidify to complete the voltage resistance sealing at the connection position of the large and small flat cables; the telescopic pipe is fastened by a trapezoidal thread and a pin. After the large and small flat cables are connected, the distance is adjusted through the telescopic pipe to avoid the cable from bending and being deformed by tension; the internal pressure of the hydraulic anchor is monitored through the pump working condition; the wellhead suspension device and the downhole suspension fishing head have basically the same structure, and various types of claws can be installed according to the different sizes of the tubing hanger at the operation wellhead, with a wide application range and strong practicability.

[0034] 8. Through the temporary suspension at the wellhead of the present invention, the cable can be fixed by bolt clamping and the packing position can be adjusted. By arranging the packer and the hydraulic anchor on the unit at the same time and lowering them into the well together with the unit, after reaching the predetermined position, the internal expansion bladder of the hydraulic anchor is pressurized to anchor the unit at the predetermined depth and play a packing role at the same time, without the need to lower the packer in advance, which saves time and effort. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a schematic diagram of arranging the internal fittings at the wellhead in the embodiment of the present invention.

[0036] Figure 2 This is a schematic diagram showing that in an embodiment of the present invention, the fishing and lowering unit is lowered through a cable winch, and the power cable of the steel wire is temporarily suspended and fastened at the wellhead.

[0037] Figure 3 This is a schematic diagram showing that in an embodiment of the present invention, a temporary elevator and a wellhead suspension device are placed on the tubing hanger by a crane.

[0038] Figure 4 This is a schematic diagram of the crown block structure in an embodiment of the present invention.

[0039] Figure 5 This is a schematic diagram of the traveling block structure in an embodiment of the present invention.

[0040] Figure 6 This is a schematic diagram of the power cable structure of the steel wire in an embodiment of the present invention.

[0041] Figure 7 This is a schematic diagram of the downhole suspension fishing head structure in an embodiment of the present invention.

[0042] Figure 8 This is a schematic diagram of the glue injection cylinder structure in an embodiment of the present invention.

[0043] Figure 9 This is a schematic diagram of the telescopic pipe structure in an embodiment of the present invention.

[0044] Figure 10 This is a schematic diagram of the hydraulic anchor and its pressure test system in an embodiment of the present invention.

[0045] Figure 11 This is a schematic diagram of the wellhead suspension device structure in an embodiment of the present invention.

[0046] Figure 12 This is a schematic diagram of the temporary elevator structure in an embodiment of the present invention.

[0047] Figure 13 This is a schematic diagram of the wellhead temporary suspension structure in an embodiment of the present invention.

[0048] Figure 14 This is a schematic diagram showing the removal of the hoisting mechanism, the placement of a large-bore production tree, and the leading out of the cable in an embodiment of the present invention.

[0049] Figure 15 This is the overall process flow chart of another embodiment of the present invention.

[0050] In the figure:

[0051] 1. Crown block 1-1. Claw 1-2. Flap;

[0052] 2. Traveling block 2-1. Claw 2-2. Flap;

[0053] 3. Large-diameter production tree;

[0054] 4. Cable reel 4-1. Tensile display instrument;

[0055] 5. Perforated pipe;

[0056] 6. Positioning seal;

[0057] 7. Deep well safety valve;

[0058] 8. Hydraulically controlled sliding sleeve;

[0059] 9. Second casing;

[0060] 10. First casing;

[0061] 11. First hydraulic control pipeline;

[0062] 12. Second hydraulic control pipeline;

[0063] 13. Blowout preventer group;

[0064] 14. Lifting flange;

[0065] 15. Steel wire power cable 15-1. Coarse steel wire 15-2. Insulation layer

[0066] 15-3 Cable core;

[0067] 16. Downhole suspension fishing head 16-1. Main bolt nut 16-2. Anti-backlash bolt 16-3. Copper cone;

[0068] 17. Sealing cylinder 17-1. Glue filling hole 17-2. Observation hole;

[0069] 18. Telescopic pipe 18-1. First telescopic pipe 18-2. Second telescopic pipe;

[0070] 19. Packer;

[0071] 20. Hydraulic anchor 20-1. Anchor claw 20-2. Expansion bladder

[0072] 20-3. Pressure pipeline;

[0073] 21. Lead-in cable;

[0074] 22. Unit;

[0075] 23. Pump working condition;

[0076] 24. Wellhead suspension device 24-1. Main bolt nut 24-2. Anti-backlash bolt 24-3. Copper cone 24-4. Claw;

[0077] 25. Temporary elevator;

[0078] 26. Temporary suspension at wellhead 26-1. T-shaped pressure plate 26-2. Copper core sleeve;

[0079] 27. Tubing hanger. Specific implementation mode

[0080] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0081] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0082] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "installation", "connection", "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. 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 situations.

[0083] The embodiments of the present invention will be further described below with reference to the accompanying drawings:

[0084] As Figure 1As shown in the figure, a wire-powered cable fishing unit system includes a first casing 10, which is a 9-5 / 8-inch casing. Inside the first casing 10, there is a second casing 9, which is a 5.5-inch casing. The first casing 10 and the second casing 9 are coaxial. Below the second casing 9, there are a hydraulic control sliding sleeve 8, a deep well safety valve 7, a positioning seal 6, and a perforated pipe 5 in sequence. One end of the first hydraulic control pipeline 11 is connected to the deep well safety valve 7, and the other end of the first hydraulic control pipeline 11 is connected to the wellhead. The deep well safety valve 7 prevents blowout in the well. When the pressure of the safety valve is abnormal, the pressure of the deep well safety valve 7 can be monitored through the hydraulic control pipeline connected to the wellhead. One end of the second hydraulic control pipeline 12 is connected to the hydraulic control sliding sleeve 8, and the other end of the second hydraulic control pipeline 12 is connected to the wellhead, ensuring that after the packer 19 is activated, chemical agent injection, well killing, and well flushing operations can be carried out through the hydraulic control sliding sleeve 8.

[0085] In this embodiment, a double-layer casing is adopted. The upper and lower parts of the 5.5-inch casing are separated by the packer 19, and the fishing unit 22 is anchored by the hydraulic anchor 20. The upper half of the 5.5-inch casing functions as a tubing. When the fishing unit 22 operates, there is no need to lower the tubing, the process is simple, the operation is convenient, and at the same time, the operation cost is reduced.

[0086] Specifically, as Figure 2 shown in the figure, a tubing hanger 27, a lifting flange 14, and a blowout preventer group 13 are sequentially arranged at the wellhead. The first end of the wire-powered cable 15 passes through the tubing hanger 27, the lifting flange 14, and the blowout preventer group 13 and then enters the second casing 9. The first end of the wire-powered cable 15 is sequentially connected to the downhole suspension fishing head 16, the sealing cylinder 17, the telescopic pipe 18, the packer 19, the hydraulic anchor 20, the lead-in cable 21, the fishing unit 22, and the pump condition 23. In this embodiment, by arranging the lifting flange 14 at the wellhead, the operation space for the installation of the wellhead suspension device 24 and the connection of the cable is increased. By arranging the wellhead blowout preventer group 13 when the fishing unit 22 is lowered during the operation, the risk of blowout is avoided. The second end of the wire-powered cable 15 is placed outside the wellhead, and the second end of the wire-powered cable 15 is connected to the cable winch 4. As Figure 2 shown in the figure, there is a tension display instrument 4-1 on the cable winch 4. When the fishing unit 22 is lowered and raised through the wire-powered cable 15, if it is found that the fishing unit 22 is stuck or falls into the well at an accelerated speed, and when the tension display exceeds the maximum tension that the wire-powered cable 15 can withstand, the operation should be stopped in time or the operation process should be adjusted.

[0087] As Figure 3As shown, when the unit 22 descends to a predetermined depth, the outer side of the steel wire power cable 15 is fixedly suspended temporarily at the wellhead 26. The wellhead temporary suspension 26 is placed on the tubing hanger 27. After the unit 22 stabilizes, the steel wire power cable 15 is removed, and the outer steel wires of the steel wire power cable 15 are connected to the wellhead suspension device 24. The wellhead suspension device 24 is connected to the temporary lifting clamp 25. After the steel wire power cable 15 is fully stressed and tightened, the wellhead temporary suspension 26 is removed, the wellhead suspension device 24 is placed on the tubing hanger 27, the temporary lifting clamp 25 is removed, and the large-diameter production tree 3 is installed. In this embodiment, by customizing the large-diameter production tree 3, when the unit 22 fails and needs to be lifted out of the well later, the unit 22 can be directly lifted through the steel wire power cable 15 and pass through the production tree. When lowering the well, the unit 22 can directly pass through the production tree and enter the well, and the operation of lifting and lowering the unit 22 does not require the removal of the production tree.

[0088] As Figure 2 shown, the second end of the steel wire power cable 15 in this embodiment passes through the crown block 1, the traveling block 2 and is connected to the cable winch 4. Specifically, as Figure 4 shown, the crown block 1 provided in this embodiment includes a connecting frame. A movable plate 1-2 is provided on the connecting frame. The steel wire power cable 15 is embedded in the crown block 1 from the movable plate 1-2. One end of the connecting frame is connected to the central axis of the crown block 1, and the other end of the connecting frame is connected to the claw 1-1. The claw 1-1 fixes the crown block 1 on the platform work site stand or the lifting mechanism. As Figure 5 shown, the structure of the traveling block 2 is the same as that of the crown block 1. The setting of the crown block 1 and the traveling block 2 increases the working space and operating distance at the wellhead position. The pulley block is fixed on the platform work site stand or the lifting mechanism through the claw 1-1. A movable plate 1-2 is provided beside the pulley block, which is convenient for the steel wire power cable 15 to be embedded in the pulley from the side, which is convenient and efficient.

[0089] Specifically, as Figure 6 shown, the steel wire power cable 15 provided in this embodiment is of a multi-strand structure. A circle of thick steel wires 15-1 is evenly distributed in a ring on the outer side of the steel wire power cable 15. The diameter of the thick steel wires 15-1 is 2 mm, and the material is an anti-corrosion material. Specifically, the thick steel wires 15-1 provided in this embodiment are galvanized steel wires and 316 steel wires. Cable cores 15-3 are evenly distributed in a ring at the center of the steel wire power cable 15. The middle cable cores 15-3 are not stressed. An insulating layer 15-2 is provided between the thick steel wires 15-1 and the cable cores 15-3. After the outer steel wires are fixed by a special tool, the bearing tension can reach 20 t, while that of a conventional unit is 10 t.

[0090] In this embodiment, the top of the downhole suspension fishing head 16 is made into the size and style of the fishing head, which is convenient for fishing operations after accidental falling into the well. Specifically, as Figure 7As shown in the figure, the downhole suspension fishing head 16 provided in this embodiment has a cavity inside. Inside the cavity, a copper cone 16-3 and a bolt group are arranged in sequence from top to bottom. The bolt group includes a main bolt cap 16-1 and an anti-backlash bolt 16-2. The bolt group presses the copper cone 16-3. The copper cone 16-3 has two layers, and the copper cone 16-3 can also be a 316 stainless steel cone. When in use, after peeling the outer steel wire of the steel wire power cable 15, press the outer steel wire of the steel wire power cable 15, or press the 316 stainless steel cone through the bolt group, press the thick steel wire 15-1 on the outside of the steel wire power cable 15, and fasten the steel wire through the pressing force or the principle of stainless steel adhesion and metal miscibility.

[0091] As Figure 8 shown in the figure, the sealing cylinder 17 provided in this embodiment is cylindrical. A through hole is provided on the central axis of the sealing cylinder 17. The sealing cylinder 17 is coaxial with the through hole. The inside of the sealing cylinder 17 is a cavity structure. Glue injection holes 17-1 and observation holes 17-2 are provided on the outer cylindrical surface of the sealing cylinder 17. Both the glue injection hole 17-1 and the observation hole 17-2 communicate with the cavity structure. In this embodiment, by providing the glue injection hole 17-1 and the observation hole 17-2 above the sealing cylinder 17, after connecting the large and small flat cables, inject glue through the glue injection hole 17-1. When it is seen in the observation hole 17-2 that the sealing glue emerges, stop injecting glue and wait for the sealing glue to solidify to complete the pressure resistance sealing of the connection position of the large and small flat cables.

[0092] For the two-layer telescopic pipe 18 of this embodiment, specifically, as Figure 9 shown in the figure, the telescopic pipe 18 of this embodiment includes a first telescopic pipe 18-1 and a second telescopic pipe 18-2. A trapezoidal thread and a pin are provided at the connection between the first telescopic pipe 18-1 and the second telescopic pipe 18-2. The trapezoidal thread connects the first telescopic pipe 18-1 and the second telescopic pipe 18-2, and the pin fastens the first telescopic pipe 18-1 and the second telescopic pipe 18-2. Through the fastening of the trapezoidal thread and the pin, the mating length of the trapezoidal thread is adjustable within the range of 1000 mm to 3000 mm. After connecting the large and small flat cables, adjust the distance through the telescopic pipe 18 to avoid the cable from bending and being deformed by tension.

[0093] As Figure 10 shown in the figure, the outside of the hydraulic anchor 20 is a structure of anchor claws 20-1. An expansion bladder 20-2 is provided inside the hydraulic anchor 20. The expansion bladder 20-2 is connected to the pump condition 23 through a pressure pipeline 20-3, and the internal pressure is monitored through the pump condition 23.

[0094] As Figure 11 shown in the figure, the wellhead suspension device 24 in this embodiment is basically the same as the downhole suspension fishing head 16 in structure. There are key grooves and bolts on the outside of the wellhead suspension device 24, and various types of claw 24-4 can be installed according to the different sizes of the tubing hanger 27 at the operation wellhead.

[0095] After the standby unit 22 stabilizes, remove the steel wire power cable 15, and connect the outer steel wire of the steel wire power cable 15 to the wellhead suspension device 24. Connect the wellhead suspension device 24 to the temporary elevator 25. After the steel wire power cable 15 is fully stressed and tightened, remove the temporary wellhead suspension 26, place the wellhead suspension device 24 on the tubing hanger 27, and remove the temporary elevator 25. As Figure 12 shown, install the large-bore production tree 3.

[0096] As Figure 13 shown, the temporary wellhead suspension 26 includes a T-shaped pressing plate 26-1 and a copper core sleeve 26-2. There are two groups of T-shaped pressing plates 26-1 and two groups of copper core sleeves 26-2. After the two groups of T-shaped pressing plates 26-1 and the two groups of copper core sleeves 26-2 are bolted and fixed, they are symmetrically arranged left and right. The copper core sleeve 26-2 is internally provided with a friction groove. The inner diameter of the copper core sleeve 26-2 is slightly smaller than the outer diameter of the steel wire power cable 15. The copper core sleeve 26-2 is clamped by bolts to fix the steel wire power cable 15.

[0097] After the first operation is completed, if the unit 22 fails and it is necessary to lift the unit 22 for maintenance and lower a new unit 22, by releasing the pressure inside the hydraulic anchor 20, the anchoring of the unit 22 in the wellbore is released, the steel wire power cable 15 is lifted, and the steel wire power cable 15 drives the downhole unit 22 and the tool string, passes through the large-bore production tree 3, and is lifted out of the wellhead. There is no need to trip the tubing and no need to remove the production tree. As Figure 14 shown, by installing the packer 19 and the hydraulic anchor 20 on the unit 22 at the same time and lowering them together with the unit 22, after reaching the predetermined position, the expansion bladder 20-2 inside the hydraulic anchor 20 is pressurized, which not only anchors the unit 22 at the predetermined depth but also plays a sealing role, eliminating the need to lower the packer 19 in advance.

[0098] As Figure 15 shown, the present invention also provides an operation method for a steel wire power cable fishing unit system. Using the above-mentioned steel wire power cable fishing unit system, it includes the following steps.

[0099] S1: Move the derrick, wash and kill the well, remove the original conventional production tree, install the blowout preventer group 13 and conduct a pressure test.

[0100] S2: Pull out the conventional string inside the original wellhead, lower the second casing 9 into the wellhead. The bottom of the second casing 9 is equipped with a deep well safety valve 7 and a hydraulic control sliding sleeve 8. Connect one end of the first hydraulic control pipeline 11 and the second hydraulic control pipeline 12 to the deep well safety valve 7 and the hydraulic control sliding sleeve 8 respectively, and connect the other ends of the first hydraulic control pipeline 11 and the second hydraulic control pipeline 12 to the wellhead.

[0101] S3: Close the deep well safety valve 7 and the hydraulic control sliding sleeve 8, and remove the blowout preventer group 13.

[0102] S4: Install the tubing hanger 27 and the lifting flange 14 to increase the installation and construction space for the wellhead temporary suspension 26 device and the wellhead suspension device 24.

[0103] S5: After reinstalling the blowout preventer group 13, conduct a pressure test.

[0104] S6: Connect the unit 22 and the pump condition 23.

[0105] S7: Sequentially connect the hydraulic anchor 20, the packer 19, the telescopic pipe 18, and the downhole suspension fishing head 16 above the unit 22. The hydraulic anchor 20 is connected to the pump condition 23 through a hydraulic control pipeline.

[0106] S8: Fix the crown block 1 and the traveling block 2 on the derrick using the jaw. Drive the wire power cable 15 with the cable winch 4. Open the trap door beside the crown block 1 and the traveling block 2 to quickly snap the cable into the crown block 1 and the traveling block 2 from the side. Lower the unit 22 and the tool string. During the process, monitor the tension of the unit 22 and the tool string with the tension indicator 4-1.

[0107] S9: When reaching the expected depth, apply pressure to the hydraulic anchor 20 to fix the unit 22 with the hydraulic anchor 20, isolate the well fluid below and the oil production path above with the packer 19, and monitor the internal pressure of the hydraulic anchor 20 using the pump condition 23.

[0108] S10: At the wellhead position, tightly fasten the wellhead temporary suspension 26 outside the wire power cable 15. Start the cable winch 4 and place the wellhead temporary suspension 26 on the tubing hanger 27.

[0109] S11: Cut off the wire power cable 15, remove the crown block 1 and the traveling block 2. Connect the end of the wire power cable 15 to the wellhead suspension device 24 and the temporary elevator 25 to solve the problem of the wellhead suspension device 24 passing through the pulley block. The wellhead temporary suspension 26 device is fastened by pressing the wire power cable 15, and its safety factor is lower than that of the wellhead suspension device 24.

[0110] S12: Use a crane to lift the wellhead suspension device 24 and the temporary elevator 25, and straighten the wire power cable 15. At this time, the wellhead temporary suspension 26 is not stressed.

[0111] S13: Remove the wellhead temporary suspension 26, slowly place the wellhead suspension device 24 on the wellhead tubing hanger 27 with a crane. After placing it stably, remove the temporary elevator 25.

[0112] S14: Install the large-bore production tree 3 at the wellhead, connect the cable core to the power cable used on the ground. The power cable passes through the cable penetrator on the large-bore production tree 3, lead out the wire power cable 15 fishing system, and connect it to the ground electrical equipment.

[0113] The advantages and positive effects of the present invention are:

[0114] 1. The present invention has a simple structure and is easy to operate. By designing a series of special tools and operating processes, a series of problems such as how to prevent the unit from rotating underground when the unit is suspended by a steel wire power cable, how to connect large and small flat cables, how to seal after connection, wellhead suspension process, and fixation of the steel wire power cable to the unit are solved.

[0115] 2. The first casing of the present invention is 9 5 / 8-inch in size, and the second casing of 5.5-inch in size is inserted into the inner side of the first casing. Double-layer casing is used, and the upper and lower parts of the 5.5-inch casing are separated by a packer. The unit is anchored by a hydraulic anchor, so that the upper half of the 5.5-inch casing acts as an oil pipe. There is no need to insert an oil pipe during unit operation, which simplifies the process, is easy to operate, and reduces operating costs.

[0116] 3. The two layers of casing of the present invention are connected in sequence to the hydraulic control sleeve and the deep well safety valve. One end of the second hydraulic control pipeline is connected to the hydraulic control sleeve, and the other end is connected to the wellhead, ensuring that after the packer is activated, chemical injection, well pressure and well washing operations can be carried out through the hydraulic control sleeve. One end of the first hydraulic control pipeline is connected to the deep well safety valve, and the other end is connected to the wellhead. The deep well safety valve prevents underground blowouts. When the safety valve pressure is abnormal, the deep well safety valve pressure is monitored through the hydraulic control pipeline connected to the wellhead, which has strong safety.

[0117] 4. The present invention increases the working space for installing the on-well suspension device and connecting the cables by arranging a lifting flange at the wellhead; the blowout preventer group at the wellhead is arranged when the salvaging unit is lowered to avoid the risk of blowout; the working space and operating distance at the wellhead are increased by using the top pulley and the ground pulley. The pulley group is fixed to the platform operation site scaffold or lifting mechanism by means of claws. A movable plate is provided on the side of the pulley group to facilitate the insertion of the wire power cable into the pulley from the side, which is convenient and efficient; the customized large-diameter oil tree is used, so that when the unit fails to lift the well in the future, the wire power cable can be directly passed through the oil tree to lift the unit. When lowering the well, the unit can be directly lowered through the oil tree. The oil tree does not need to be dismantled for the unit lifting and lowering operations, which saves time and effort.

[0118] 5. The cable retractor of the present invention is provided with a tension display. When the unit is raised or lowered by the steel power cable, if the unit is found to be stuck or accelerated to fall into the well, and the tension display exceeds the maximum tension that the steel power cable can withstand, the operation can be stopped or the operation process can be adjusted in time, thereby increasing the safety factor.

[0119] 6. The top of the downhole suspension fishing head of the present invention is made in the size and style of a fishing head, which is convenient for fishing operations after accidental falling into the well. Inside, two circles of copper cones are pressed tightly by a bolt group. After peeling the outer steel wires of the steel wire power cable, the outer steel wires of the steel wire power cable are pressed tightly, or 316 stainless steel cones are pressed tightly by a bolt group to press the outer steel wires of the steel wire power cable. According to the principle of stainless steel sticking buckle and similar solubility of metals, the steel wires are fastened with strong firmness.

[0120] 7. For the voltage resistance and insulation sealing of the connection of the large and small flat cables of the present invention, a glue filling hole and an observation hole are provided above the sealing cylinder. After the large and small flat cables are connected, glue is filled through the glue filling hole. When sealant is seen to emerge from the observation hole, stop filling the glue and wait for the sealant to solidify to complete the voltage resistance sealing at the connection position of the large and small flat cables; the telescopic pipe is fastened by trapezoidal threads and pins. After the large and small flat cables are connected, the distance is adjusted through the telescopic pipe to avoid bending and tensile deformation of the cables; the internal pressure of the hydraulic anchor is monitored through the pump working condition; the structure of the wellhead suspension device is basically the same as that of the downhole suspension fishing head, and various types of claws can be installed according to the different sizes of the tubing hanger at the operation wellhead, with a wide application range and strong practicability.

[0121] 8. Through temporary suspension at the wellhead, the present invention can clamp and fix the cable with bolts and adjust the packer position. By installing the packer and the hydraulic anchor on the unit at the same time and lowering them together with the unit, after reaching the predetermined position, the internal expansion bladder of the hydraulic anchor is pressurized to anchor the unit at the predetermined depth and play a packing role at the same time, eliminating the need to lower the packer in advance, saving time and effort.

[0122] The above has described the embodiments of the present invention in detail, but the content described is only the preferred embodiments of the present invention and cannot be considered as limiting the scope of implementation of the present invention. All equivalent changes and improvements made according to the scope of the application of the present invention shall still fall within the scope covered by the patent of the present invention.

Claims

1. A wire-powered cable fishing unit system, characterized in that: It includes a first casing, inside which there is a second casing. The first casing and the second casing are coaxial. Below the second casing, there are successively a hydraulic sliding sleeve, a deep well safety valve, a positioning seal and a perforated pipe. One end of the first hydraulic control pipeline is connected to the deep well safety valve, and the other end of the first hydraulic control pipeline is connected to the wellhead. One end of the second hydraulic control pipeline is connected to the hydraulic sliding sleeve, and the other end of the second hydraulic control pipeline is connected to the wellhead. The wellhead is successively provided with a tubing hanger, a lifting flange and a blowout preventer group. The first end of the wire power cable passes through the tubing hanger, the lifting flange and the blowout preventer group and then enters the second casing. The first end of the wire power cable is successively connected to a downhole suspended fishing head, a sealing cylinder, a telescopic pipe, a packer, a hydraulic anchor, a unit and a pump condition. The second end of the wire power cable is placed outside the wellhead and is connected to a cable winch. When the unit descends to a predetermined depth, the outside of the wire power cable is fixedly and temporarily suspended at the wellhead. The wellhead temporary suspension is placed on the tubing hanger. After the unit is stable, the wire power cable is removed, and the outer steel wires of the wire power cable are connected to the wellhead suspension device. The wellhead suspension device is connected to a temporary elevator. After the wire power cable is completely stressed and tightened, the wellhead temporary suspension is removed, and the wellhead suspension device is placed on the tubing hanger. The temporary elevator is removed, and a large-bore production tree is installed. The wire power cable is of a multi-strand structure. A circle of thick steel wires is evenly distributed in a ring shape on the outside of the wire power cable. The diameter of the thick steel wires is 2 mm. Cable cores are evenly distributed in a ring shape at the center of the wire power cable. An insulating layer is provided between the thick steel wires and the cable cores. The wellhead temporary suspension includes a T-shaped pressing plate and a copper core sleeve. There are two groups of the T-shaped pressing plate and the copper core sleeve respectively. After the two groups of the T-shaped pressing plate and the copper core sleeve are fixed by bolts, they are symmetrically arranged left and right. A friction groove is provided inside the copper core sleeve. The copper core sleeve fixes the cable after being clamped by the bolts.

2. The wire-powered cable fishing unit system according to claim 1, wherein: The first casing is a 9-5 / 8-inch casing, and the second casing is a 5.5-inch casing.

3. A wire power cable fishing unit system according to claim 1 or 2, characterized in that: The second end of the wire power cable passes through a crown block and a traveling block and is connected to the cable winch. The crown block includes a connecting frame, on which a movable plate is provided. The wire power cable is embedded into the crown block from the movable plate. One end of the connecting frame is connected to the central shaft of the crown block, and the other end of the connecting frame is connected to a claw, which fixes the crown block on a platform work site stand or a hoisting mechanism. The structure of the traveling block is the same as that of the crown block.

4. A wire-powered cable fishing unit system according to claim 1 or 2, characterized in that: There is a cavity inside the downhole suspended fishing head. Inside the cavity, there are successively a copper cone and a bolt group from top to bottom. The bolt group includes a main bolt cap and an anti-back-off bolt. The bolt group presses the copper cone, and the copper cone has two layers.

5. A wire-powered cable fishing unit system according to claim 1 or 2, characterized in that: The sealing cylinder is cylindrical. There is a through hole on the central axis of the sealing cylinder. The sealing cylinder and the through hole are coaxial. The inside of the sealing cylinder is of a cavity structure. Glue injection holes and observation holes are provided on the outer cylindrical surface of the sealing cylinder. The glue injection holes and the observation holes are both communicated with the cavity structure.

6. A wire power cable fishing unit system according to claim 1 or 2, characterized in that: The telescopic tube includes a first telescopic tube and a second telescopic tube. A trapezoidal thread and a pin are provided at the connection between the first telescopic tube and the second telescopic tube. The trapezoidal thread connects the first telescopic tube and the second telescopic tube, and the pin fastens the first telescopic tube and the second telescopic tube.

7. A wire power cable fishing unit system according to claim 1 or 2, characterized in that: The outer side of the hydraulic anchor is an anchor claw structure, and the inner side of the hydraulic anchor is provided with an expansion bag, and the expansion bag is connected to the pump working condition through a pressure pipeline, and the internal pressure is monitored through the pump working condition.

8. A method for operating a wire-powered cable fishing unit system, which utilizes a wire-powered cable fishing unit system according to any one of claims 1 to 7, characterized in that: The following steps are included: S1: Remove the original conventional Christmas tree, install the BOP stack and conduct pressure test; S2: Lower a second casing into the wellhead. A deep-well safety valve and a hydraulically controlled sliding sleeve are attached to the bottom of the second casing. Connect one end of the first hydraulically controlled pipeline and the second hydraulically controlled pipeline to the deep-well safety valve and the hydraulically controlled sliding sleeve, respectively. Connect the other ends of the first hydraulically controlled pipeline and the second hydraulically controlled pipeline to the wellhead. S3: closing the deep well safety valve and the hydraulic control sleeve, and removing the blowout preventer assembly; S4: Install the oil pipe hanger and lifting flange; S5: reinstall the blowout preventer group and conduct pressure test; S6: Connect the unit and the pump working condition; S7: Connecting a hydraulic anchor, a packer, a telescopic pipe and a downhole suspended fishing head in sequence above the unit, wherein the hydraulic anchor is connected to the pump working condition via a hydraulic control line; S8: Fix the top pulley and the bottom pulley on the derrick, use the cable retractor to drive the steel wire power cable, and lower the unit and tool string; S9: When the hydraulic anchor is lowered to the expected depth, pressure is applied to the hydraulic anchor; S10: At the wellhead, the outer side of the steel power cable is fastened to the wellhead for temporary suspension, and the cable retractor is started to place the wellhead temporary suspension on the oil pipe hanger; S11: Cutting off the steel wire power cable, removing the top pulley and the ground pulley, and connecting the end of the steel wire power cable to the wellhead suspension device and the temporary elevator; S12: hoisting the wellhead suspension device and the temporary elevator, and straightening the steel wire power cable; S13: removing the temporary wellhead suspension, slowly placing the wellhead suspension device on the wellhead oil pipe hook, and removing the temporary elevator after it is stably placed; S14: Install a large-diameter Christmas tree at the wellhead, connect the cable core to the ground power cable, pass the power cable through the cable pass-through on the large-diameter Christmas tree, lead out the steel wire power cable casting and fishing system, and connect to the ground electrical equipment.

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