Shaft casing taking system

Abstract

The invention provides a shaft sleeve taking system, relates to the technical field of well repair of petroleum engineering, and aims to solve the technical problems of low sleeve taking efficiency, long period, generation of a large amount of iron wires and scrap iron, incomplete well flowback and environmental pollution due to adoption of a sleeve milling tool and a grinding and milling tool in the prior art. The heating device is used for heating a casing in a shaft; the conveying system is connected with the electromagnetic induction heating system and used for adjusting the position of the electromagnetic induction heating system in the shaft; the power distribution system is used for providing power for the electromagnetic induction heating system; and the control system is connected with the electromagnetic induction heating system, the conveying system and the power distribution system. According to the electromagnetic induction principle, the casing pipe and cement stone outside the casing pipe are heated, the bonding force between the casing pipe and the cement stone is damaged, and the device has the advantages of being high in integration degree and operation efficiency, safe, high in environmental protection performance and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of workover in petroleum engineering, and more particularly to a casing removal system for a wellbore. Background Art

[0002] In recent years, with the continuous development and utilization of offshore oil and gas resources, the problem of shortage of well slots has emerged on offshore platforms. In order to achieve the goal of maximizing the overall oil recovery rate of the oilfield and minimizing the economic investment, it has become an effective and lowest-cost way to utilize the existing faulty wells or inefficient wells on the platform for sidetracking adjustment wells and reuse the old wellbores. In order to expand the size of the sidetracked wellbore, it is necessary to remove the casing that is currently cemented in the wellbore.

[0003] Currently, for casing removal technology, milling tools and grinding tools are mostly used. When the central casing and the outer casing have good centering and large gaps, milling tools are used; when milling is unsuccessful, grinding tools will be used to grind all the casings into fragments for backflow treatment. The casing removal efficiency is low, the cycle is long, and a large amount of iron wire and iron filings are generated. The wellbore backflow is not clean, and there is an environmental pollution problem.

[0004] Therefore, there is an urgent need for a casing removal system for a wellbore to solve the above technical problems. Summary of the Invention

[0005] The purpose of the present invention is to provide a casing removal system for a wellbore to solve the technical problems in the prior art that for casing removal technology, milling tools and grinding tools are mostly used. When the central casing and the outer casing have good centering and large gaps, milling tools are used; when milling is unsuccessful, grinding tools will be used to grind all the casings into fragments for backflow treatment. The casing removal efficiency is low, the cycle is long, and a large amount of iron wire and iron filings are generated. The wellbore backflow is not clean, and the environment is polluted. The preferred technical solutions provided by the present invention can produce many technical effects as described below.

[0006] To achieve the above purpose, the present invention provides the following technical solutions:

[0007] A casing removal system for a wellbore provided by the present invention includes:

[0008] An electromagnetic induction heating system for heating the casing in the wellbore;

[0009] A conveying system connected to the electromagnetic induction heating system for adjusting the position of the electromagnetic induction heating system in the wellbore;

[0010] A power distribution system for supplying power to the electromagnetic induction heating system;

[0011] A control system connected to the electromagnetic induction heating system, the conveying system, and the power distribution system.

[0012] Preferably, a cooling system is further included. The cooling system includes a water tank, a water inlet pipeline and a water return pipeline connected to the water tank. Among them, a pump is provided on the water inlet pipeline, and the water tank is connected to the electromagnetic induction heating system through the water inlet pipeline and the water return pipeline.

[0013] Preferably, an explosion-proof system is further included. The explosion-proof system includes an inert gas source and a gas pipeline. Among them, the inert gas source is connected to the electromagnetic induction heating system through the gas pipeline.

[0014] Preferably, the control system includes a control component and a monitoring component, where:

[0015] The control component includes a control console, and the electromagnetic induction heating system, the conveying system, and the power distribution system are all controlled through the control console;

[0016] The monitoring component includes a signal line, and the signal line is connected to the control console.

[0017] Preferably, the electromagnetic induction heating system includes an induction heating device, a heating coil, a cooling pipeline, a gas pipeline, and a signal acquisition unit, where:

[0018] The induction heating device includes an inverter;

[0019] The cooling pipeline is connected to the water inlet pipeline and the water return pipeline;

[0020] The gas pipeline is connected to the gas pipeline;

[0021] The signal acquisition unit is connected to the signal line.

[0022] Preferably, the power distribution system includes a power distribution cabinet, a power line and a normal pressure line connected to the power distribution cabinet, and the power distribution cabinet is connected to the inverter through the power line.

[0023] Preferably, the conveying system includes a drum, a drum bracket, a guiding arm and an umbilical cable. The drum is arranged on the drum bracket, the umbilical cable is wound around the drum, and one end of the umbilical cable passes through the guiding arm and is connected to the induction heating device.

[0024] Preferably, the guiding arm includes a plurality of pin shafts and rollers connected to the pin shafts. The plurality of rollers are arranged in a parabolic trajectory line, and the umbilical cable passes through the trajectory line and is connected to the induction heating device.

[0025] Preferably, the guiding arm further includes double-row crescent plates, a support truss and a bottom plate. The lower end of the support truss is connected to the bottom plate, and the upper end of the support truss is connected to the crescent plates. The pin shafts are arranged between the double-row crescent plates.

[0026] Preferably, the umbilical cable includes steel stranded wires, and the power line, the gas pipeline, the water inlet pipeline, the water return pipeline and the signal line are wrapped inside the steel stranded wires.

[0027] The wellbore casing removal system provided by the present invention includes an electromagnetic induction heating system, a conveying system, a power distribution system and a control system. By setting the electromagnetic induction heating system to heat the casing in the wellbore, the energy conversion efficiency is high, the casing and the cement sheath outside the casing can be effectively heated, the adhesion between the casing and the cement sheath outside the casing is destroyed, the operation efficiency is high, and during the electromagnetic induction heating process, no iron wire or iron filings are generated, no drilling fluid circulation is required, and the environmental pollution is small. Description of the Drawings

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0029] Figure 1 is a schematic structural diagram of an embodiment of the wellbore casing removal system of the present invention;

[0030] Figure 2 is a schematic structural diagram of the umbilical cable in the wellbore casing removal system of the present invention.

[0031] In the figure: 1, control console; 2, power distribution cabinet; 3, inert gas source; 4, water tank; 5, pump; 6, drum; 7, drum support; 8, umbilical cable; 9, guiding arm; 10, roller; 11, crescent plate; 12, support truss; 13, bottom plate; 14, induction heating device; 15, frequency converter; 16, heating coil; 17, power line; 18, normal pressure line; 19, gas pipeline; 20, water inlet pipeline; 21, water return pipeline; 22, signal line; 23, steel stranded wire. Detailed Embodiments

[0032] In order to make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be described in detail below. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other implementation manners obtained by those of ordinary skill in the art without creative efforts belong to the scope protected by the present invention.

[0033] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "lateral", "length", "width", "height", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "side", etc. is based on the orientation or positional relationship shown in the 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.

[0034] In the description of the present invention, it should also be noted that unless otherwise clearly specified and limited, the terms "installed", "connected", "connected to" 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. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0035] Figure 1 is a schematic structural diagram of this embodiment. As Figure 1 shown, this embodiment provides a wellbore casing removal system, including an electromagnetic induction heating system, a conveying system, a power distribution system, and a control system.

[0036] Among them, the electromagnetic induction heating system is used to heat the casing in the wellbore. The conveying system is connected to the electromagnetic induction heating system and is used to adjust the position of the electromagnetic induction heating system in the wellbore; the power distribution system is used to provide power for the electromagnetic induction heating system; the control system is connected to the electromagnetic induction heating system, the conveying system, and the power distribution system.

[0037] The electromagnetic induction heating system in this embodiment includes an induction heating device 14 and a heating coil 16. The induction heating device 14 includes an inverter 15. The control system includes a console 1. The power distribution system includes a power distribution cabinet 2 and a power line 17. During operation, the power supply is turned on through the console 1, and high-power electrical energy is transmitted from the power distribution cabinet 2 to the inverter 15 in the downhole induction heating device 14 through the power line 17. After step-down and frequency modulation, it enters the heating coil 16. The alternating current generates an alternating magnetic field around the heating coil 16, and then eddy currents are generated on the casing in the magnetic field. The eddy current energy is converted into heat energy to heat the casing, and the casing heats the cement sheath outside the casing through heat transfer. Due to the difference in the thermal expansion coefficients of the casing and the cement sheath, the adhesion between the casing and the cement sheath is destroyed through the principle of thermal expansion and contraction.

[0038] This wellbore casing removal system heats the casing in the wellbore by setting up an electromagnetic induction heating system, with high energy conversion efficiency. It can effectively heat the casing and the cement sheath outside the casing, break the bonding force between the casing and the cement sheath outside the casing, has high operation efficiency, and during the electromagnetic induction heating process, no iron wires or iron filings are generated, no drilling fluid circulation is required, and the environmental pollution is small.

[0039] As an optional implementation, the wellbore casing removal system further includes a cooling system. The cooling system includes a water tank 4, a water inlet pipeline 20 and a water return pipeline 21 connected to the water tank 4. Among them, a pump 5 is provided on the water inlet pipeline 20, and the water tank 4 is connected to the electromagnetic induction heating system through the water inlet pipeline 20 and the water return pipeline 21.

[0040] Specifically, a cooling pipeline is provided in the electromagnetic induction heating system in this embodiment, and the cooling pipeline is connected to the water inlet pipeline 20 and the water return pipeline 21. During operation, the pump 5 is started through the control system to draw cold water out of the water tank 4, and after pressurization, it is pumped through the water inlet pipeline 20 to the cooling pipeline in the downhole induction heating device 14 to cool the frequency converter 15 in the induction heating device 14. The heated water returns to the water tank 4 through the water return pipeline 21, and the whole cycle continues until the construction ends, ensuring that the frequency converter 15 does not overheat and can continue to work normally.

[0041] As an optional implementation, the wellbore casing removal system further includes an explosion-proof system. The explosion-proof system includes an inert gas source 3 and a gas pipeline 19. Among them, the inert gas source 3 is connected to the electromagnetic induction heating system through the gas pipeline 19.

[0042] Specifically, a gas pipeline is provided in the electromagnetic induction heating system in this embodiment, and the gas pipeline is connected to the gas pipeline 19. During operation, the console 1 turns on the inert gas source 3, injects inert gas from the inert gas source 3 into the downhole induction heating device 14 through the gas pipeline 19, and after returning from the downhole induction heating device 14, it returns to the wellhead through the wellbore. The whole gas injection process continues until the construction ends, ensuring that the hydrocarbon gas cracked from the oil stain on the inner wall of the casing during the heating process can be diluted and carried out of the wellhead, effectively avoiding the accumulation of hydrocarbon gas, shielding the contact between the hydrocarbon gas and oxygen at high temperature, preventing combustion and explosion, and ensuring downhole safety.

[0043] As an optional implementation, the conveying system includes a drum 6, a drum support 7, a guiding arm 9 and an umbilical cable 8. The drum 6 is arranged on the drum support 7, the umbilical cable 8 is wound around the drum 6, and one end of the umbilical cable 8 passes through the guiding arm 9 and is connected to the induction heating device 14.

[0044] The guiding arm 9 in this embodiment includes a plurality of pin shafts and rollers 10 connected to the pin shafts. The plurality of rollers 10 are arranged in a parabolic trajectory line, and the umbilical cable 8 passes through the trajectory line formed by the arrangement of the plurality of rollers 10 and is connected to the induction heating device 14.

[0045] Specifically, the guiding arm 9 in this embodiment further includes a double-row crescent plate 11, a support truss 12, and a bottom plate 13. The lower end of the support truss 12 is connected to the bottom plate 13, and the upper end of the support truss 12 is connected to the crescent plate 11. A pin shaft is arranged between the double-row crescent plates 11.

[0046] During use, the rotation of the roller 6 is controlled through the console 1, thereby controlling the lowering speed of the umbilical cable 8, and the induction heating device 14 is lowered to the target depth in the casing.

[0047] As an optional implementation manner, the control system includes a control component and a monitoring component. Among them, the control component includes the console 1, and the electromagnetic induction heating system, the conveying system, and the power distribution system are all controlled through the console 1.

[0048] Specifically, a control circuit for controlling the delivery of the inert gas source 3, the opening and closing of the pump 5, the rotation speed and direction of the roller 6, and the opening and closing of the downhole induction heating device 14 is arranged in the console 1. The console 1 is used to control the delivery of the inert gas source 3, the opening and closing of the pump 5, the rotation speed and direction of the roller 6, and the opening and closing of the downhole induction heating device 14.

[0049] The monitoring component includes a signal line 22. The signal line 22 is connected to the console 1, and a signal decoding circuit and a display circuit are arranged in the console 1. The induction heating device 14 in this embodiment includes a signal acquisition unit, and the signal acquisition unit is connected to the signal line 22.

[0050] During operation, after the working parameters such as the voltage, current, and temperature of the frequency converter 15 are collected by the signal acquisition unit in the downhole induction heating device 14, they are transmitted to the console 1 through the signal line 22 after specific encoding, and are displayed on the console 1 after decoding, which is convenient for the operator to control the operation progress.

[0051] As an optional implementation manner, the power distribution system includes a power distribution cabinet 2, and a power line 17 and a normal pressure line 18 connected to the power distribution cabinet 2. The power distribution cabinet 2 is connected to the frequency converter 15 through the power line 17, and the power distribution cabinet 2 is connected to the power transmission circuit of the console.

[0052] As an optional implementation manner, Figure 2 is a schematic structural diagram of the umbilical cable in this embodiment. As Figure 2 shown, the umbilical cable 8 includes steel strands 23, and the inside of the steel strands 23 wraps the power line 17, the gas pipeline 19, the water inlet pipeline 20, the water return pipeline 21, and the signal line 22.

[0053] The working process of this embodiment includes:

[0054] Install the guiding arm 9 near the wellhead. Install the power distribution cabinet 2, inert gas source 3, water tank 4, pump 5, control console 1, drum 6 and drum support 7 at appropriate positions on the platform, and connect the power line 17, atmospheric pressure line 18, gas pipeline 19, water inlet pipeline 20, water return pipeline 21 and signal line 22 between the various devices as required. Connect one end of the umbilical cable 8 through the roller 10 in the guiding arm 9 to the downhole induction heating device 14 in the wellhead.

[0055] The control console 1 controls the lowering speed of the umbilical cable 8 by controlling the drum 6, and lowers the downhole induction heating device 14 to the target depth in the casing.

[0056] The control console 1 starts the pump 5, pumps the cooling water out of the water tank 4, and pumps it through the water inlet pipeline 20 to the cooling pipeline in the downhole induction heating device 14 after pressurization to cool the frequency converter 15. The heated water returns to the water tank 4 through the water return pipeline 21. The whole cycle continues until the construction is completed to ensure that the frequency converter 15 does not overheat and can continue to work normally.

[0057] The control console 1 turns on the inert gas source 3, injects the inert gas from the inert gas source 3 into the downhole induction heating device 14 through the gas pipeline 19. After returning from the downhole induction heating device 14, it returns to the wellhead through the wellbore. The whole gas injection process continues until the construction is completed to ensure that the hydrocarbon gas cracked from the oil stain on the inner wall of the casing during the heating process can be diluted and carried out of the wellhead, effectively avoiding the accumulation of hydrocarbon gas, shielding the contact between the hydrocarbon gas and oxygen at high temperature, preventing combustion and explosion, and ensuring downhole safety.

[0058] The control console 1 turns on the power supply, transports the high-power electric energy from the power distribution cabinet 2 to the frequency converter 15 in the downhole induction heating device 14 through the power line 17. After stepping down and frequency modulation, it enters the heating coil 16. The alternating current generates an alternating magnetic field around the heating coil 16, and then eddy currents are generated on the casing in the magnetic field. The eddy current energy is converted into heat energy to heat the casing, and the casing heats the cement sheath outside the casing through heat transfer. Due to the difference in the thermal expansion coefficients of the casing and the cement sheath, the adhesive force between the casing and the cement sheath is destroyed by the principle of thermal expansion and contraction.

[0059] The signal acquisition unit in the downhole induction heating device 14 collects the working parameters such as the voltage, current and temperature of the frequency converter 15, and after specific encoding, transmits them to the control console 1 through the signal line 22, and is displayed on the control console 1 after decoding, which is convenient for the operator to control the operation progress.

[0060] The control console 1 controls the umbilical cable 8 through the drum 6 to move the downhole induction heating device 14 from the downhole to the wellhead direction at a speed of 12 m / h. During this process, the casing and the cement sheath outside the casing are continuously heated to destroy the adhesive force between the casing and the cement sheath, so as to facilitate the later removal operation of the casing.

[0061] As described above, it is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of changes or substitutions, which should all be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims described above.

Claims

1. A wellbore casing removal system, characterized in that: include: Electromagnetic induction heating system, used to heat the casing in the wellbore; a conveying system connected to the electromagnetic induction heating system and used to adjust the position of the electromagnetic induction heating system in the wellbore; A power distribution system, used to provide power to the electromagnetic induction heating system; A control system is connected to the electromagnetic induction heating system, the conveying system, and the power distribution system.

2. A wellbore casing removal system according to claim 1, characterized in that: The invention also comprises a cooling system, the cooling system comprising a water tank (4), a water inlet pipeline (20) and a water return pipeline (21) connected to the water tank (4), wherein a pump (5) is arranged on the water inlet pipeline (20), and the water tank (4) is connected to the electromagnetic induction heating system via the water inlet pipeline (20) and the water return pipeline (21).

3. A wellbore casing removal system according to claim 2, characterized in that: It also includes an explosion-proof system, which includes an inert gas source (3) and a gas pipeline (19), wherein the inert gas source (3) is connected to the electromagnetic induction heating system through the gas pipeline (19).

4. A wellbore casing removal system according to claim 3, characterized in that: The control system includes a control component and a monitoring component, wherein: The control component comprises a control console (1), and the electromagnetic induction heating system, the conveying system, and the power distribution system are all controlled by the control console (1); The monitoring component comprises a signal line (22), and the signal line (22) is connected to the console (1).

5. A wellbore casing removal system according to claim 4, characterized in that: The electromagnetic induction heating system comprises an induction heating device (14), a heating coil (16), a cooling pipeline, an air pipeline and a signal acquisition unit, wherein: The induction heating device (14) comprises a frequency converter (15); The cooling pipeline is connected to the water inlet pipeline (20) and the water return pipeline (21); The air pipeline is connected to the air pipeline line (19); The signal collection unit is connected to the signal line (22).

6. A wellbore casing removal system according to claim 5, characterized in that: The power distribution system comprises a power distribution cabinet (2), and a power line (17) and a normal voltage line (18) connected to the power distribution cabinet (2); the power distribution cabinet (2) is connected to the frequency converter (15) via the power line (17).

7. A wellbore casing removal system according to claim 6, characterized in that: The conveying system comprises a roller (6), a roller bracket (7), a guide arm (9) and an umbilical cable (8), wherein the roller (6) is arranged on the roller bracket (7), the umbilical cable (8) is wound around the roller (6), and one end of the umbilical cable (8) passes through the guide arm (9) and is connected to the induction heating device (14).

8. A wellbore casing removal system according to claim 7, characterized in that: The guide arm (9) comprises a plurality of pins and rollers (10) connected to the pins, the plurality of rollers (10) are arranged in a parabolic trajectory, and the umbilical cable (8) passes through the trajectory and is connected to the induction heating device (14).

9. A wellbore casing removal system according to claim 8, characterized in that: The guide arm (9) further comprises a double row of crescent plates (11), a support truss (12) and a base plate (13), wherein the lower end of the support truss (12) is connected to the base plate (13), the upper end of the support truss (12) is connected to the crescent plate (11), and the pin shaft is arranged between the double row of crescent plates (11).

10. A wellbore casing removal system according to any one of claims 7 to 9, characterized in that: The umbilical cable (8) comprises a steel strand (23), the interior of which encases the power line (17), the gas pipeline (19), the water inlet pipeline (20), the water return pipeline (21) and the signal line (22).

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