RU32177U1 - Pipe cutting device - Google Patents

Description

g 0 vo.- ;: Device for cutting pipes

The utility model relates to mining, to the field of equipment for wells, can be used for cutting pipes located in the well, mainly casing, with a jet of abrasive fluid, during canalization of wells during isolation of formation water, separation of formations and hydraulic fractures.

A device is known for cutting pipes (AS USSR No. 694626, class ЕВВ 29/00, publ. 30.10.79), comprising a housing with a saddle and channels, in which bushings with nozzles are installed and equipped with cassettes located in the channels of the housing, and bushings with nozzles are spring-loaded and mounted in cassettes with the possibility of longitudinal movement.

The disadvantages of this device are:

- Large hydrodynamic force on the load bearing;

with this design of the rotation unit, it exceeds 4.9 tons and can reach up to 10 tons or more, which leads to rapid wear of the bearing and jamming of the structure during the work process;

- the location of the nozzles in the housing at an angle of 90 ° to the radial axis leads to a sharp decrease in the efficiency of the process, since the waterjet in this case does not affect the fracture surface perpendicularly, but at an angle of less than 35-40 °;

that is, the main part of the kinetic energy in this device is directed mainly to the rotation of the body, and not to the cutting process. In addition, an abrasive plug (sand plug) will be formed in the wellbore, additional funds will be required to flush it;

- lack of brake, which leads to a large angular speed of rotation of the housing with nozzles (exceeding 3000-5000 rpm even in a liquid medium);

this leads to the destruction of the compactness of the waterjet, a significant loss of its kinetic energy and an increase in cutting time;

- the presence in the device of only two nozzles is clearly not enough, which increases the duration of the cutting process;

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- the absence of nozzles installed in the radial direction, contributing to the most efficient use of the kinetic energy of the waterjet, accelerating the cutting process and deeper development of the formation;

- the extension of the bushings with nozzles during operation when cutting pipes with a diameter less than the extension length (span) leads to jamming of the device;

this is due to the force of the fluid acting on the piston and reaching, with a pressure drop of AR 20-25 MPa (standard cutting mode) up to 1.4 - 1.8 tons;

- the absence of rigid fixation (fixing unit) of the device leads to an increase in the cutting time;

this is due to the pulsation of the working pressure at the wellhead during work at 1.0 - 2.5 MPa, which is typical for the operation of ground-based pumping units, as a result of which the device at the bottom will move tens of millimeters (mm) vertically.

The closest in technical essence and the achieved result is a device for cutting pipes (AS USSR No. 590434, class ЕВВ 29/00, publ. 30.01.78), containing a housing with a saddle and radial channels, in which are installed by means of nozzle holders , a sleeve with radial channels, movable in the axial direction for fixing the nozzles in the closed and open positions, and an anchor. At the same time, the housing at the same level with the nozzles has additional radial channels, in each of which there is a piston with a shield and a clamp, locked in the initial position by a shear element, while the clamp is installed with the possibility of interaction with the piston, and the rod with the sleeve.

The disadvantages of this device are:

- the rotation of the device is carried out by rotating the entire drill pipe string with the wellhead rotor; rotation of drill pipes in production, technical or other casing during the cutting process (which is 1.5 - 2.5 hours) usually leads to abrasion of its walls in places of curvature (since in practice there are no perfectly vertical wells) and disruption its tightness with all the ensuing consequences, namely, the large costs of

repair work and long downtime of wells. In addition, this device cannot be used in directional and horizontal wells;

- insufficiently efficient use of kinetic energy of a hydroabrasive jet, which is aimed only at cutting;

- the presence in the device of only two nozzles is clearly not enough, which increases the duration of the cutting process;

-strictly horizontal arrangement of nozzles in the radial direction can lead to destruction of the nozzle holder by a reverse waterjet and damage the device during the cutting process. In addition, this contributes to the formation of abrasive plugs at the bottom, for the washing of which additional funds will be required;

- fixing device - the anchor is located below the cutting plane, which limits the scope of the device; this is due to the fact that when working with stressed production cores of large diameter and weight, after cutting, the entire weight of the liner (and it can reach up to 60 tons or more) and the force of elastic deformation through the anchor will be transferred to the device and drill pipes, which may not additional load and tear; this will lead to their fall to the bottom of the well, which will require significant costs for their extraction to the surface.

The technical result of the proposed utility model is to increase the efficiency of the kinetic energy of the hydroabrasive jet while increasing the operational reliability of the device.

This result is achieved by the fact that in the device for cutting pipes containing the mounting unit of the device to the pipe string, a cutting unit with horizontally radially opposed hydroabrasive nozzles, a fixing unit and a seat with a valve, there is a compensator for additional load forces and a hydraulic brake, the attachment unit of the device to the pipe string is located in the upper part of the compensator, and the cutting unit is located below the fixing unit, inside the compensator there is a hollow plate with a piston can be moved vertically, the hollow shaft of the compensator is rigidly fixed to the fixing unit, consisting of a housing made with cylindrical holes in which retractable anchors with their travel stops and folding springs are located, the fixing unit

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made rigidly attached to a fixed hollow shaft, the hollow shaft is made with holes coaxial with waterjet nozzles located in the housing of the cutting unit and having plugs, the housing of the cutting unit with nozzles is made to rotate around the fixed hollow shaft, while horizontally opposed to each other in at least two nozzles are made in the radial direction, the cutting unit has additional waterjet nozzles, pairwise remote from the vertical axis and located at an angle m 30-70 ° to the radial horizontal axis, the axis of all waterjet nozzles are directed at an angle of 5-15 ° up to the horizontal plane, and the hydraulic brake is attached to the bottom of the rotating cutting unit by means of a threaded joint and is made with rigidly fixed blades.

The presence of a compensator in the design of the device allows you to remove the resulting additional load on the device when pumping a cold (relative to the wellbore) hydroabrasive medium, leading to thermal compression of the pipe string. The location of the locking device above the cutting unit eliminates the additional loads on the device that arise when working with stressed production cores of large diameter and weight, leading to a violation of the integrity of the device and the breakage of drill pipes. The presence of additional waterjet nozzles, pairwise remote from the vertical axis and located at an angle of 30-70 ° to the radial horizontal axis, and the direction of the axes of all waterjet nozzles at an angle of 5-15 ° up to the horizontal plane eliminates the destruction of the nozzle holder by a reverse waterjet jet. In addition, the presence of additional waterjet nozzles located in the aforementioned manner ensures the cutting of the pipe around the entire circumference and increases the efficiency of using the kinetic energy of the waterjet jet due to the creation of the optimal torque value on the device. The presence of a hydraulic brake allows for the rotation of the cutting unit at the required stable speeds, which provide a more efficient use of the kinetic energy of the waterjet and an optimal cutting process.

The drawing shows a device for cutting pipes.

In FIG. 1 is a front view, a vertical section.

In FIG. 2 - waterjet nozzles, their location and section along the plane AA.

The device comprises a compensator 1, a fixing unit 2, a working cutting unit 3 and a hydraulic brake 4.

Compressor 1 consists of a housing 5, inside of which the hollow rod 6 with a piston and a seal 7 is arranged with vertical movement, springs 9 are located between the nut 8 and the piston of the rod 6, the upper part of the housing 5 of the compensator 1 is equipped with an adapter 10 for attaching the pipe cutting device to pipe string.

The hollow rod 6 of the compensator 1 is rigidly attached to the fixing unit 2, which consists of a housing 11, cylindrical holes 12, retractable anchors 13, their travel stops 14 and folding springs 15.

The locking unit 2, in turn, is rigidly attached to the stationary hollow shaft 16 of the cutting cutting unit 3, which, in addition to the hollow shaft 16, consists of a housing 17 with waterjet nozzles 18 and plugs 19, angular contact bearings 20, thrust bearings 21 and 22, sealing glands 23 and 24, pressure caps 25, a valve seat 26 located in the lower part of the hollow stationary shaft 16 and the ball valve 27.

The presence of the cutting unit 3 of angular contact bearings 20, sealing glands 23 and 24 and clamping caps 25 ensures tightness and the possibility of rotation of the housing with waterjet nozzles around a stationary hollow shaft 16, in which there are holes 28, the centers of which are on the same axis with waterjet nozzles 18.

This design of the working unit of cutting 3 allows you to balance the hydraulic pressure of the liquid on the upper and lower parts and remove the load pressure on the angular contact bearings 20.

Waterjet nozzles 18 are located in the housing 17 as follows.

At least two waterjet nozzles are located opposite each other and are removed from the vertical axis in the radial direction. The remaining nozzles are pairwise remote from the vertical axis and are located at an angle of 30-70 ° to the radial horizontal axis. In addition, the axis of all nozzles are directed at an angle P of 5-15 ° up to the horizontal plane. The hydraulic brake 4 by means of a threaded connection is attached to the lower pressure cover 25 of the rotating cutting assembly 3 and consists of a nut 29, to which the blades 30 are rigidly attached.

The device is lowered into the well on a column of pressure pipes (not shown) to a predetermined cutting depth. A water-abrasive mixture (water with sand, a solution with an abrasive, etc.) is fed through pressure pipes by ground pumps at a pressure of 25-30 MPa. In this case, the ball valve 27 hermetically closes the flushing hole of the landing seat 26, the pressure in the device increases sharply and acts on the pistons of the anchors 13, which, in turn, extend outward against the inner forming pipe (columns) and rigidly fix the device in a vertical position at the same level .

The compensator 1 at this time relieves the arising; additional load forces when pumping a cold (relative to the wellbore) hydroabrasive medium, leading to thermal compression of the pipe string. When this occurs, the compression of the spring 9, and the housing 5 together with the nut 8, sub 10 and the bottom of the pipe string are moved up.

The water-abrasive mixture through the holes 28 in the hollow shaft 16 enters the water-abrasive nozzles 18 and expires from them at a speed of 200-210 m / s, forming a reactive recoil. The reactive force of the flowing waterjet from nozzles installed at an angle to the radial axis, begins to unwind and rotate the cutting unit 3 around its axis.

When the values of the angle a are less than 30 °, the efficiency of using the reactive power of the hydroabrasive medium to rotate the cutting cutting unit sharply decreases, i.e. the torque becomes insufficient to overcome the friction force on the seals and the hydraulic resistance of the surrounding fluid medium. When the values of the angle a are greater than 70 °, the efficiency of the cutting process is sharply reduced, since the angle of the jet attack on the cut surface decreases less than 35-40 ° and the main energy is spent on creating a large torque on the device.

The installation of the axes of all nozzles at an angle of p of 5-15 ° upward relative to the horizontal plane allows avoiding the rapid destruction of the nozzle holder and the device body with a reverse water jet, facilitating the removal of spent abrasive (sand) from the cutting plane and preventing the formation of abrasive (or sharply reduce the likelihood) traffic jams at the bottom. Setting the axes at an angle of less than 5 ° is impractical due to the large destructive force of the reverse hydroabrasive jet, and at values of the angle p of 15 ° the cutting efficiency is lost and its duration increases.

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In this case, the pipe is cut along the entire circumference with waterjet jets. The duration of the cutting process depends on the diameter of the pipe being cut, the thickness of its wall, the number of nozzles, their location, speed (volumes) of the pumped waterjet medium and for pipes with a diameter of 62 to 245 mm it ranges from 20 minutes to 2 hours.

The hydraulic brake 4 at low revolutions of the cutting cutting unit 3 exerts insignificant resistance to rotation, however, with an increase (revolutions) in peripheral speed, the hydraulic resistance of the medium to the surface of the blades 30 increases and after a while the acceleration stops and the device starts to work at stable required revolutions, ensuring an optimal cutting process . The calculation of the geometric parameters of the hydraulic brake is carried out according to well-known formulas, taking into account the flow rate of the pumped abrasive medium, the design features of the cutting cutting unit, the location of the nozzles, the viscosity and density of the working fluid.

The presence of a hydraulic brake helps to prevent the abrasive from settling on the bottom of the well, since its blades face upward with the working part and act as a hydraulic centrifugal pump. At the same time, the treated abrasive (sand, etc.) is removed by a jet of liquid from the blades of the hydraulic brake from the cutting plane, is picked up by an upward flow of liquid and carried to the surface.

Example. Industrial tests of the pipe cutting device were carried out at a depth of 1310 m when cutting cemented (stuck) in a 219 mm production string 168 mm tubing. The process was carried out as follows: in a 168 mm string, a device for cutting pipes with six nozzles with a diameter of 128 mm was lowered on 89 tubing pipes (PKT) and installed opposite the specified interval. By means of the CHAN-700 and TsA-320 ground-based pumping units, a hydroabrasive mixture (100 g of sand per 1 liter of brine) was supplied to 89 tubing at a pressure of 27.0 MPa and a flow rate of 18.0 l / s. After 45 minutes of cutting, circulation appeared in the annulus (there was no circulation before). After another 25 minutes, the feed of the abrasive mixture was stopped. Flush the well with technical solution until sand is completely removed. Then they lifted 89 mm tubing and released 168 mm tubing. The total cutting time was 1 hour 10 minutes. No complications were observed.

The proposed design of a device for cutting pipes allows you to:

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J iz - prevent possible breakage of pressure pipes after the cutting process of the column; - Prevent premature destruction of the nozzle holder; -improve the process of removing spent abrasive from the plane of pipe cutting (to prevent the formation of sand plugs at the bottom); -accelerate the process of cutting pipes; -increase the energy efficiency of the waterjet mixture; -increase the reliability and uninterrupted operation of the device; - Prevent abrasion and leakage of the production string. The economic effect of using this device compared to the steel ones is 150-200 thousand rubles per well operation. - 8 -

Claims (1)

A device for cutting pipes, comprising a unit for attaching the device to the pipe string, a housing with a seat and a valve, a cutting unit with horizontally radially opposed hydroabrasive nozzles and a fixing unit, characterized in that the device comprises a compensator for additional load forces and a hydraulic brake, the attachment unit of the device to the pipe string is located in the upper part of the compensator, and the cutting unit is located below the fixing unit, a hollow rod is located inside the compensator with a piston with the possibility of vertical movement, the hollow rod of the compensator is rigidly attached to the fixing unit, consisting of a housing made with cylindrical holes in which retractable anchors with limiters of their travel and folding springs are located, the fixing unit is made rigidly attached to the fixed hollow shaft, the hollow shaft is made with holes coaxial with waterjet nozzles located in the body of the cutting unit and having plugs, the body of the cutting unit with nozzles is made with the possibility of at least two nozzles are horizontally opposed to each other in a radial direction, the cutting unit has additional waterjet nozzles, pairwise remote from the vertical axis and located at an angle of 30-70 ° to the radial horizontal axis, the axis of all waterjet nozzles are directed at an angle of 5-15 ° up to the horizontal plane, and the hydraulic brake is attached to the bottom of the rotating cutting unit by means of a threaded connection and is made with the same tightly fixed blades.