SU1184924A1 - Downhole pipe cutter - Google Patents

Description

The invention relates to the drilling

wells, in particular to devices,

used for cutting pipes in the well.

The aim of the invention is to increase the efficiency of the device by regulating the force on the cutters in the cutting process and prevent damage to the cutters and casing during intermediate washes. θ

Figure 1 shows the proposed downhole pipe cutter, the section in figure 2 view C in figure 1 ’, in fig.Z - node I in figure 1.

The downhole pipe cutter contains a hollow body 1 with a stepped sleeve 2 and a return spring 3. In the lower part of the sleeve has a tapered surface A. In the side windows of the body there are hinged cutters 4 20 with return springs ί. In the upper part of the stepped sleeve 2 there is a tapered saddle B for a recessed plug

6. Inside the waste plug 6, containing in the lower part of the bottom 7, a stepped sleeve 8 is installed, with a jet pump 9 placed in it, connected to the rod 10, which has a blind axial channel B and a slotted window 11. In the upper part, the rod has stabilizing ribs 12 for centering the recess when it moves in the pipes. The jet pump 9 contains a nozzle 13, a receiving chamber 14, hydraulically connected with an annular cavity G through the openings 15, and forms a sealed cavity with the stem and the inner wall of the plug D. Signal holes 16 are made in the wall of the hollow body 1. The cavity between the hollow body and the stepped sleeve in which the return spring 3 is placed is sealed and filled with a liquid, for example mineral oil. Sealing of moving parts is carried out (5) with sealing rings. A slotted window 11 of variable cross section is made in a section narrowing towards the surface of the plug.

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A cap 17 and a plug 18 are placed in the wall of the hollow body. The plug 18 (FIG. 3) consists of “sleeve 19, filter 20, throttle channel 21, valve 22, springs 23rd of the clamping nut 5 and 24.

Well pipe cutter works as follows.

A pipe cutter without a waste plug 6 is lowered on the pipes into the well with intermediate flushing through the central channel of the stepped sleeve 2. When the depth of cut is reached, the waste plug 6 is lowered into the pipes. After the stepped sleeve overlaps the drilling mud with the stop plug.

When this begins to work the jet pump, sucking the fluid from the cavity G through the holes 15. As a result of reducing the pressure in the cavity G, the stepped sleeve 8 together with the rod moves down. At. this gradually overlaps the slot window ^ causing an increase in the injection pressure, indicating an approaching moment of the overlap of the circulation channel. With increasing pressure to a predetermined value, the pump is turned off. The inertia of the moving flow of the solution leads to the downward displacement of the stepped sleeve. When moving the liner, the energy of the hydraulic shock is extinguished due to the deformation of the spring and the extrusion of the damping fluid through the throttle channel of the plug 18. Due to this contact of the stepped sleeve 2 with the cutters 4 does not occur, since the sleeve is installed at some distance from the cutters surface. Stabilization of pressure in the pipes of the pig shows a complete overlap of the channel. With a further increase in pressure to a predetermined value, a further displacement of the stepped sleeve occurs and the incisors advance. Rotation of the pipe cutter will cut the pipe. A further increase in pressure as the incisors deepen into the body of the pipe increases the force on the incisors. At the moment when the pipe is cut, the stepped sleeve will move downwards, opening the signal holes 16. At the same time, due to the release of the solution into the annular space, the pressure will decrease, indicating the end of the pipe cutting process. At the end of the cutting, the pipes are depressurized at the wellhead. Under the action of hydrostatic pressure in the well, the stepped bushing 8 with the stem 10 will move upwards, opening the slot window 11 and providing a hydraulic connection of the in-tube space above and below the locking element.

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1184924

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After that, under the action of the return springs, the stepped sleeve 2 and the cutters 4 will occupy the initial position. Since the circulation channel after moving up the stepped sleeve 8 with the rod 10 is open, when lifting the pipe cutter, the solution from the drill pipes will flow freely into the · borehole. While moving the liner up, the mud filtrate through the filter 20 and the valve 22 of the plug 18 will fill the spring cavity between

5 step sleeve 2 and body 1, which allows the pipe cutter to be used repeatedly without lifting it from the well.

FIG. 3

Φυδ. 1 FIG. 2

Claims (2)

1. Borehole pipe, containing a hollow body with side windows, a spring-loaded stepped sleeve with a throttling unit in the upper part, installed in the body with the ability to interact with spring-loaded cutters placed in the body windows, and an overflow valve, characterized in that increase the efficiency of the device by regulating the force on the cutters in the process of cutting and preventing damage to the incisors and casing during intermediate washes, the throttling unit is designed as a waste plug with a surface in which a stepped bushing with a rod in the upper part and a jet pump integrated into it is mounted; the cavity of the tube under the sleeve, and the cavity of the tube under the sleeve with the stem and the inner wall of the tube forms a sealed cavity, while in the rod is made of a hollow axial channel, reported with the receiving chamber of the jet pump, and a side slotted window, which communicates the housing cavity under the plug with the axial channel of the rod, and the landing seat for the dump plug is made in the stepped sleeve. 2. Pipe cutter according to claim 1, in accordance with the fact that the side slotted window of the rod is made in a section narrowing towards the surface of the plug. avaA □ about > 1 1184924 2