CN112253027B - Ocean abandonment well head cutting device based on plasma arc cutting - Google Patents

Abstract

The invention relates to a plasma arc cutting-based marine abandoned wellhead cutting device and its application, comprising a supporting mechanism, a rotating mechanism, a feeding mechanism, a cutting mechanism and a guiding mechanism; The rotating mechanism is located in the center of the casing. The rotating mechanism is used to drive the rotation of the feeding mechanism and the cutting mechanism to achieve the purpose of circumcising the casing. The feeding mechanism is used to adjust the distance between the cutting mechanism and the inner wall of the casing. In order to generate a high-temperature plasma arc and realize the cutting operation, the guiding mechanism provides guidance for the entire device, ensuring that the device can be smoothly lowered along the axial direction of the casing. The wellhead cutting device of the invention has the advantages of simple and compact structure, good stability, low equipment manufacturing cost and wide application range. The plasma arc is used for cutting, the cutting force is small, no vibration is generated, the cutting is efficient and pollution-free, the operation cost can be greatly reduced, and the wellhead cutting device has the advantages of high efficiency and no pollution. The economic benefits and market value are worthy of popularization and application.

Description

A cutting device for marine abandoned wellhead based on plasma arc cutting

technical field

The invention relates to a cutting device for marine abandoned wellheads based on plasma arc cutting, and belongs to the technical field of oil drilling and production equipment.

Background technique

At present, with the development of the offshore oil production industry, a large number of offshore oil production platforms are built in the marine field. The offshore platforms have a service life. When the service life is reached, they must be dismantled. According to relevant regulations in my country, for marine abandoned wellheads, the casing cement sheath including the underwater wellhead system four meters below the mudline must be cut and recycled, and no artificial structures should be left above the mudline. Therefore, a special marine abandoned well cutting and recovery device is required to complete this task. At present, the methods of cutting subsea abandoned wells at home and abroad mainly include mechanical cutting, abrasive water jet cutting and energy-gathering cutting.

Mechanical cutting mainly uses a hydraulic cutter to cut the casing, which is a traditional cutting method. The main disadvantage of this method is that the cutting force is large during cutting, the vibration of the device is very obvious, the cutter wears quickly, and the cutter is in the It is not easy to replace underwater fractures. In addition, for non-concentric multi-layer casing cement ring structures, mechanical cutting is also prone to eccentricity. Abrasive water jet cutting mainly mixes some high-hardness abrasive grains in high-pressure water jet, and sprays the abrasive grains to the casing wall through high-pressure water, converting the pressure energy into kinetic energy of abrasive grains and water, and continuously eroding the casing , so as to complete the cutting operation. Therefore, this cutting method requires the device to have sufficient sealing performance to obtain high water pressure. Once leakage occurs, it will greatly affect the cutting effect. In addition, the device system is complex, bulky, and costly. Higher, with water depth application limitations, and faster jet nozzle wear, these factors limit the application of this method to the seabed. Condensed energy cutting is to use explosives to blast the casing. The blasting process is not easy to control, and it will cause environmental pollution, so it is not suitable for subsea wellhead casing cutting. In addition, Chinese patent document CN102513645A also discloses a device for cutting deep-water casing by using an electric arc. The advantage of this method is that the cutting method belongs to non-contact cutting, the cutting force is small, the device vibration will not be generated, and the arc processing The efficiency is high, and the cutting process will not produce pollution. In addition, this set of equipment has an ingenious structure. The cutting mechanism is located in the middle of the entire device, and the electrode can be fed directly underwater. The two ends of the device are provided with upper and lower righting mechanisms. , which is used to position the device in the center of the casing, so that the cutting can be carried out smoothly. However, this method of cutting the wellhead with arc also has shortcomings. The arc cutting can only process the benign conductors of electricity such as metal components. For the wellhead casing The cement ring between them cannot achieve a good cutting effect.

Therefore, it is necessary to design a set of dedicated marine abandoned wellhead cutting equipment to overcome the shortcomings of the above cutting methods and meet the requirements of economy, reliability, stability, efficiency and environmental protection in the cutting operation of marine abandoned wellheads, so as to reduce the The purpose of job costing.

SUMMARY OF THE INVENTION

Aiming at the disadvantages of high cutting cost, low efficiency, large cutting force, large vibration, poor stability, pollution, etc. existing in the current marine abandoned wellhead cutting technology, the present invention provides a marine abandoned wellhead cutting device based on plasma arc cutting. The cutting efficiency is high, the destructive force is strong, the cutting force is small, and it can cut metal and non-metal characteristics. Introducing it into the offshore well abandonment cutting operation can greatly improve the cutting speed, reduce the cutting cost, and truly achieve high Efficiency green cutting.

The technical scheme of the present invention is as follows:

An abandoned marine wellhead cutting device based on plasma arc cutting, comprising a supporting mechanism, a rotating mechanism, a feeding mechanism, a cutting mechanism and a guiding mechanism, wherein the rotating mechanism is arranged at the bottom end of the supporting mechanism, and the feeding mechanism is arranged at the rotating mechanism The bottom end of the cutting mechanism and the guiding mechanism are arranged on the feeding mechanism;

Wherein, the support mechanism is used to support the entire device on the inner wall of the wellhead casing, limit the degree of freedom of the entire device in the casing, ensure that the lower rotating mechanism is located in the center of the casing, and ensure smooth cutting operations;

The rotating mechanism is used to drive the feeding mechanism and the cutting mechanism to rotate, so as to realize annular cutting;

The feeding mechanism is used to drive the cutting mechanism to achieve feeding in the direction of the pipe wall, so as to adjust the distance between the cutting mechanism and the inner wall of the casing, so as to ensure that the cutting operation has sufficient cutting depth;

The cutting mechanism is used to generate a plasma arc with high energy concentration, so as to realize the cutting operation of the casing in the abandoned wellhead;

The guiding mechanism is used to guide the entire device, so that the entire device can be smoothly lowered along the direction of the casing, and at the same time, it provides protection for the cutting mechanism and the feeding mechanism located above it to avoid the cutting mechanism and the feeding mechanism when the device is lowered. A direct collision occurs with the pipe wall.

Preferably, the supporting mechanism includes a supporting cylinder, a steel wire rope, a moving plate, a fixed plate, a connecting plate, a lug seat, a long connecting rod, a short connecting rod and a clamping claw, and the supporting cylinder is located in the axial center of the supporting mechanism and is used for feeding the supporting mechanism Provide supporting driving force, the moving plate is arranged on the top of the piston rod of the supporting cylinder, which can follow the piston rod to reciprocate along the cylinder axis, the fixed plate is arranged on the top of the supporting cylinder, and the connection is arranged at the bottom of the supporting cylinder. The plate is used to connect the support mechanism and the lower rotating mechanism. Three above-mentioned steel wire ropes are arranged on the plate to lower the whole device to the designated position in the submarine casing and to pull the whole device to the sea surface after the cutting is completed. The fixed plate and the moving plate are respectively provided with six above-mentioned ear seats, each ear seat is provided with one of the above-mentioned connecting rods, and one end of the connecting rods close to the wall surface of the casing is provided with one of the above-mentioned jaws, through the extension of the cylinder piston rod. Action, the driving force is transmitted from the moving plate and the connecting rod to the claw, so that the claw is tightly attached to the inner wall of the casing, the connecting rod is connected with the ear seat and the claw by a pin, in addition to other The components are fixed with threaded connections.

Further preferably, three of the ear seats on the moving plate and the fixed plate are arranged upward, and three are arranged downward, and are distributed at equal angles along the circumferential direction of the moving plate and the fixed plate. The ear seat is provided with a long connecting rod, the upper ear seat of the fixing plate is provided with a long connecting rod, and the lower ear seat is provided with a short connecting rod. The advantage of this is that the use of the extension movement of one cylinder can realize the upper and lower layers of support, which makes the support effect more stable, and can avoid the interference between the connecting rod, the moving plate and the fixed plate during mechanical movement, and expand the connecting rod. The range of activities, thereby expanding the range of support for the entire device, and at the same time lengthening the distance between the upper and lower layers of support to further optimize the support effect.

Further preferably, the above-mentioned steel wire ropes are equiangularly distributed in the circumferential direction of the fixed plate, and the holes at the corresponding positions on the driven plate pass through the moving plate. Opening the moving plate connected to the piston rod of the support cylinder does not affect the work of the piston rod of the support cylinder.

Preferably, the rotation mechanism includes a deceleration stepper motor, which is fixed on the connecting plate of the above-mentioned support mechanism by bolts, and its function is to drive the lower feeding mechanism to rotate, and control the deceleration stepper motor through the set control program. The rotation speed of the machine is well matched with the cutting speed of the cutting mechanism to ensure that at least one layer of casing can be cut off smoothly in one operation.

Preferably, the feeding mechanism includes a feeding cylinder, a support frame, a sliding rod, a head sliding cylinder, a tail sliding cylinder, a secondary sliding cylinder, a pulley, a ferrule and a spring, and the sliding rod is arranged on the supporting frame, The two are connected by threads, the sliding rod is provided with the head sliding cylinder and the tail sliding cylinder, which can slide axially along the sliding rod, and the feeding cylinder is set between the head sliding cylinder and the tail sliding cylinder. The connection is fixed to provide the feeding driving force. The spring is provided on the piston rod of the feeding cylinder to play a buffering role. The lower end of the sliding cylinder is provided with the clamping sleeve for clamping the plasma generator, the secondary sliding cylinder and the spring are arranged on the tail sliding cylinder, which can slide along the tail sliding cylinder, and the secondary sliding cylinder is provided with the pulley. , which can roll along the circumferential direction of the inner wall of the casing. When the feeding cylinder is ventilated, the cylinder drives the head sliding cylinder and the tail sliding cylinder to feed to the casing wall along the sliding rod, and at the same time drives the ferrule and pulley on the head sliding cylinder. , and the secondary slide cylinder and pulley on the tail slide cylinder are fed to the casing wall. After the pulley contacts the casing wall, the piston rod of the feed cylinder and the spring on the tail slide cylinder are compressed to complete the feeding action and cutting operation. Ready.

Further preferably, the above-mentioned springs are respectively arranged between the above-mentioned feed cylinder piston rod and the head sliding cylinder, and between the tail sliding cylinder and the secondary sliding cylinder. The advantage of this is that the spring can buffer the contact between the above-mentioned pulley and the inner wall of the casing. The instantaneously generated collision force improves the structural force of the feeding mechanism, and the pulley also plays the role of guiding and auxiliary righting, making the cutting operation more stable.

Preferably, the cutting mechanism includes a dedicated underwater plasma generator, an outlet plug and a ventilation and energization pipeline. The plasma generator can generate a plasma arc with a high concentration of energy, which is used to realize the cutting operation. The card installed on the above-mentioned feeding mechanism In the sleeve, its position in the ferrule can be adjusted, which is convenient to adjust the fixed distance between the front end of the plasma generator and the inner wall of the casing during the cutting operation. The outlet plug is installed at the air outlet at the front end of the plasma generator. The function is to prevent the seawater from pouring into the plasma generator before the cutting operation. When the cutting operation is carried out, the high-pressure gas is ejected through the air outlet of the plasma generator, the outlet plug is pushed open, the cutting operation starts, and the ventilation and electrification pipeline is from above the sea. It leads to the position to be cut, and is installed at the tail of the plasma generator to supply gas and power to the plasma generator to generate plasma arc. In addition, a one-way is also provided near the connection between the inside of the ventilation pipeline and the tail of the plasma generator. valve to prevent backflow of seawater.

Preferably, the guide mechanism includes a frustum-shaped metal shell and an underwater camera, and the frustum-shaped metal shell is mounted on the bottom end of the support frame of the above-mentioned feeding mechanism, and is used to provide guidance for the device when the device is lowered, so that The device can be smoothly lowered along the axis of the casing, and the underwater camera is installed on the upper end of the truncated conical metal casing to observe the progress of the underwater cutting operation and determine whether the plasma arc is successfully ejected and whether the casing is successfully cut.

The beneficial effects of the present invention are:

1. The present invention adopts plasma arc to cut wellhead casing. Compared with traditional processing methods, plasma arc can cut metals and non-metals without generating cutting force. The cutting speed is extremely fast, which can greatly shorten the operation time. , the cutting process will not produce any pollutants, so cutting wellhead casing with plasma arc is environmentally friendly and efficient.

2. The support mechanism of the present invention adopts the double-layer six-jaw type support, which can stably constrain the freedom of the entire device in the downhole casing. Compared with the structure, the simplification saves a driving part, making the whole device more compact and lightweight, and the application is more convenient and flexible.

3. A pulley is installed in the feeding mechanism of the present invention, which can avoid the direct contact between the plasma generator and the inner wall of the casing, and play a protective role. The spring in the middle can buffer the instantaneous collision between the pulley and the inner wall of the casing, and can also improve the structural force of the feeding mechanism.

4. The present invention has a simple and compact structure and good stability, and can transmit underwater cutting pictures through an underwater camera to monitor the progress of the cutting work, which is convenient for real-time monitoring of parameters such as current, voltage, intake air volume and intake pressure of the plasma generator. Adjustment, compared with the previous wellhead cutting device, the equipment has low manufacturing cost and a wide range of equipment applications. A set of equipment can be used for cutting various types of wellhead casing within a certain diameter range, with high cutting efficiency and good economical efficiency. Benefit and market value, worthy of promotion and application.

Description of drawings

Fig. 1 is the perspective view of the overall structure of the present invention;

Figure 2 is a schematic structural diagram of a support mechanism in the present invention;

3 is a schematic structural diagram of a rotating mechanism, a feeding mechanism, a cutting mechanism and a guiding mechanism in the present invention;

In the figure: 1. Supporting mechanism; 2. Rotating mechanism; 3. Feeding mechanism; 4. Cutting mechanism; 5. Guiding mechanism; 6. Supporting cylinder; 7. Steel wire rope; 8. Moving plate; 9. Fixing plate; 10 , connecting plate; 11, ear seat; 12, long connecting rod; 13, short connecting rod; 14, clamping jaw; 15, deceleration stepper motor; 16, feeding cylinder; 17, supporting frame; 18, sliding rod; 19 , head slide; 20, tail slide; 21, secondary slide; 22, pulley; 23, ferrule; 24, spring; 25, plasma generator; 26, outlet plug; 27, ventilation and electrification pipeline; 28, frustum-shaped metal shell; 29, underwater camera.

Detailed ways

1 is a perspective view of the overall structure of a plasma arc cutting-based marine abandoned wellhead cutting device provided by the present invention, including a supporting mechanism 1, a rotating mechanism 2, a feeding mechanism 3, a cutting mechanism 4 and a guiding mechanism 5, and the rotating mechanism 2 is fixed. Installed on the lower end of the support mechanism 1, the feeding mechanism 3 is installed on the lower end of the rotating mechanism 2, and the cutting mechanism 4 and the guiding mechanism 5 are installed on the feeding mechanism 3;

Wherein, the support mechanism 1 is used to provide downhole support for the entire device, limit the degree of freedom of the entire device in the casing, ensure that the lower rotating mechanism 2 is located in the center of the casing, and ensure smooth cutting operations;

The rotating mechanism 2 is used to drive the feeding mechanism 3 and the cutting mechanism 4 to rotate, so as to achieve the purpose of annularly cutting the wellhead casing;

The feeding mechanism 3 is used to drive the cutting mechanism 4 to move toward the pipe wall, so as to adjust the distance between the cutting mechanism 4 and the inner wall of the casing;

The cutting mechanism 4 is used to generate a high-temperature plasma arc to realize the cutting operation;

The guiding mechanism 5 is used to guide the entire device, ensure that the device can be smoothly lowered along the axial direction of the casing, and also protect the cutting mechanism 4 and the feeding mechanism 3 from direct collision with the inner wall of the casing.

2 is a schematic structural diagram of the support mechanism in the present invention. The support mechanism 1 includes a support cylinder 6, a wire rope 7, a moving plate 8, a fixed plate 9, a connecting plate 10, an ear seat 11, a long connecting rod 12, a short connecting rod 13 and a clamp The claw 14, the claw 14 is connected with the long connecting rod 12 and the short connecting rod 13 through the pin shaft, the other end of the connecting rod is connected with the lug seat 11 through the pin shaft, and the lug seat 11 is fixed on the movable plate 8 and the fixed plate 9 through the thread , the moving plate 8 is fixed on the top of the piston rod of the supporting cylinder 6 through the thread, the fixed plate 9 is fixed on the top of the cylinder body of the supporting cylinder 6 through the thread, and the moving plate 8 is driven by the extension action of the piston rod of the supporting cylinder 6 to drive the long connecting rod 12. The short connecting rod 13 and the claw 14 move so that the claw 14 can be tightly attached to the wall of the casing, the freedom of the entire device is limited, and the supporting action is completed. When the cutting work is completed, the supporting action of the cylinder 6 When the piston rod is retracted, the jaws 14 can leave the wall of the casing, and the supporting task is completed. The pulling force is used to lower the entire device to the designated position in the subsea casing and to pull the entire device above the sea surface after the cutting is completed. The connecting plate 10 is fixed to the bottom of the cylinder block supporting the cylinder 6 through threads, which is convenient for rotation with the lower end Institution 2 is connected.

3 is a schematic structural diagram of the rotating mechanism, the feeding mechanism, the cutting mechanism and the guiding mechanism in the present invention, wherein the rotating mechanism 2 includes a deceleration stepping motor 15, which is fixed to the connecting plate 10 of the supporting mechanism 1 through bolts, and its function is to drive The lower feeding mechanism 3 and the cutting mechanism 4 rotate to realize the circumcision of the casing.

The feeding mechanism 3 includes a feeding cylinder 16, a supporting frame 17, a sliding rod 18, a head sliding cylinder 19, a tail sliding cylinder 20, a secondary sliding cylinder 21, a pulley 22, a ferrule 23 and a spring 24. The supporting frame 17 is threaded through It is connected with the key and is fixed to the rotating shaft of the decelerating stepper motor 15. The sliding rod 18 is fixed on the support frame 17 through threads. , the feeding cylinder 16 is installed between the head sliding cylinder 19 and the tail sliding cylinder 20 through a threaded connection to drive the sliding cylinder to slide, the ferrule 23 is fixed on the head sliding cylinder 19, and the secondary sliding cylinder 21 is inserted in the tail On the sliding cylinder 20, it can slide axially along the tail sliding cylinder 20, and the two pulleys 22 are respectively installed at the front end of the head sliding cylinder 19 and the secondary sliding cylinder 21, and directly contact with the inner wall of the casing, which can play a role of anti-collision, For guiding and auxiliary support, the above-mentioned spring 24 is installed between the head slide 19 and the piston rod of the feed cylinder 16, and between the secondary slide 21 and the tail slide 22, which can buffer and improve the structural stress. When the feeding cylinder 16 is extended, the head sliding cylinder 19 and the tail sliding cylinder 20 are driven to move towards the casing wall, thereby driving the secondary sliding cylinder 21, the pulley 22, the ferrule 23 and the spring 24. When feeding in the direction of the casing wall, when the pulley 22 contacts the casing wall, the piston rod of the feeding cylinder 16 and the spring 24 on the tail sliding cylinder 20 are compressed, the feeding action is completed, and the cutting operation is ready.

The cutting mechanism 4 includes a dedicated underwater plasma generator 25, an outlet plug 26 and a ventilation and electrification pipeline 27. The plasma generator 25 is clamped on the ferrule 23 of the feeding mechanism 3, and the distance between the outlet and the inner wall of the casing can be adjusted. The position is adjusted by being installed on the ferrule 23, and its function is to generate a high-temperature plasma arc and spray it to the inner wall of the casing to realize the cutting of the wellhead casing. The outlet plug 26 is inserted at the gas outlet of the plasma generator 25, Before cutting, it prevents seawater from pouring back into the plasma generator 25. When the cutting operation starts, the outlet plug 26 is pushed open by the compressed air, and the plasma arc is ejected from the nozzle of the plasma generator 25. The cutting operation is normal Carry out, the ventilation and electrification pipeline 27 has been connected to the tail of the plasma generator 25 from above the sea surface, and its function is to supply air and power to the plasma generator 25, and the connection between the ventilation and electrification pipeline 27 and the tail of the plasma generator 25 is also provided with a single The valve is used to prevent the backflow of seawater into the ventilation and electrification pipeline 27 .

The guide mechanism 5 includes a frustum-shaped metal shell 28 and an underwater camera 29. The frustum-shaped metal shell 28 is fixed on the support frame 17 of the feeding mechanism 3, and is mainly used to provide downward guidance for the entire device, and at the same time it is also the upper end of the guide. The feeding mechanism 3 and the cutting mechanism 4 provide protection to prevent the feeding mechanism 3 and the cutting mechanism 4 from colliding with the inner wall of the casing when the device is lowered. The underwater camera 29 is installed on the upper end of the frustum-shaped metal shell 28 for monitoring Observe the progress of underwater cutting work and judge whether the work is normal, so as to make real-time adjustments to the plasma working current, voltage and air pressure.

This embodiment is based on the plasma arc cutting marine abandoned wellhead cutting device, which can realize the cutting operation of the wellhead casing through the plasma arc with high energy concentration. The device structure is simple, the application is flexible, the cutting speed is fast and pollution-free, and the operation time can be greatly shortened. , saving operating costs.

Claims (5)

1. An abandoned marine wellhead cutting device based on plasma arc cutting, characterized in that it comprises a supporting mechanism, a rotating mechanism, a feeding mechanism, a cutting mechanism and a guiding mechanism, wherein the rotating mechanism is arranged at the lower end of the supporting mechanism, and the feeding The mechanism is arranged at the lower end of the rotating mechanism, and the cutting mechanism and the guiding mechanism are arranged on the feeding mechanism; Wherein, the support mechanism is used to provide support for the whole device and limit the freedom of the device in the downhole, so that the device is located in the center of the casing; The rotating mechanism is used to drive the feeding mechanism and the cutting mechanism to rotate; The feeding mechanism is used to drive the cutting mechanism to advance and retreat in the direction of the pipe wall; The cutting mechanism is used to generate a plasma arc to realize the cutting of the wellhead casing; The guide mechanism is used to provide lowering guide for the whole device; The feeding mechanism includes a feeding cylinder, a support frame, a sliding rod, a head sliding cylinder, a tail sliding cylinder, a secondary sliding cylinder, a pulley, a ferrule and a spring. The head slide cylinder and the tail slide cylinder are installed. The feed cylinder drives the slide cylinder to move. The head slide cylinder is installed with a ferrule, the tail slide cylinder is installed with a secondary slide cylinder, the head slide cylinder and the secondary slide cylinder are installed. There is a pulley installed on it, the pulley can contact with the inner wall of the casing and roll along its circumferential direction to realize the function of guiding and auxiliary centralizing. There are springs to buffer shock absorption and improve structural stress. 2. The plasma arc cutting-based marine abandoned wellhead cutting device according to claim 1, wherein the supporting mechanism comprises a supporting cylinder, a wire rope, a moving plate, a fixed plate, a connecting plate, a lug seat, a long connecting rod, Short connecting rods and claws, a total of six claws on the upper and lower layers are connected with the moving plate through the connecting rod and the ear seat. The moving plate is driven by the support cylinder to move up and down, and the claw on the connecting rod is driven to stick to the inner wall of the casing to realize the support Work. 3. The plasma arc cutting-based marine abandoned wellhead cutting device according to claim 1, wherein the rotating mechanism adopts a deceleration stepper motor, and the deceleration stepper motor is installed on the connecting plate. 4. The marine abandoned wellhead cutting device based on plasma arc cutting according to claim 1, wherein the cutting mechanism comprises an underwater dedicated plasma generator, an outlet plug and a ventilation and electrification pipeline, and the plasma generator It is clamped in the ferrule of the feeding mechanism, and its position can be adjusted. The outlet plug is inserted at the air outlet of the plasma generator to prevent the seawater from flowing into the plasma generator before the cutting operation starts. The above has been connected to the tail of the plasma generator, and a one-way valve is installed at the connection of the tail, which can prevent seawater from pouring back into the ventilation and electrification pipeline. 5. The plasma arc cutting-based marine abandoned wellhead cutting device according to claim 1, wherein the guiding mechanism comprises a frustum-shaped metal casing and an underwater camera, and the frustum-shaped metal casing is fixed on the feeding mechanism The bottom end of the supporting frame is used to realize the guidance when the device is lowered in the wellhead sleeve. The underwater camera is installed on the upper end of the conical frustum to monitor and observe the working process of the underwater cutting operation, which is convenient for the staff to make judgments and adjust the plasma. Generator current, voltage and air pressure operating parameters.

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