SU899848A1 - Device for repairing casings - Google Patents

Description

(54) DEVICE FOR REPAIRING OF CIRCUITS

one

The invention relates to repair and insulation works in wells, namely, devices for repairing casing strings in drilling and production wells.

A device for repairing a casing string is known, comprising an electrically driven body, measles, a metal plaster, a spacer sleeve on which an expanding cone, a collet sleeve, and a sleeve 1 are mounted.

A disadvantage of this device is that the collet head is released from the retaining clip before entering the perforated nipple. With the subsequent entry of the already-expanded collet head into the corrugated tube, resistance to its movement and axial loads on the device as a whole increase many times over.

The closest to the proposed technical essence and the achieved result is a device for repairing casing strings containing a housing run down on the cable, on which a metal patch is attached, and an explosive substance 2.

A disadvantage of the known device is the low reliability of the fastening of the metal patch due to the uneven distribution of the pressure of the gases of the explosive and the presence of a pinch effect during the descent into the well filled with liquid.

The purpose of the invention is to increase the reliability of fixing the metal plaster.

This goal is achieved by placing the explosive between the housing and the metal plaster.

The drawing shows the proposed device, the overall appearance; in fig. 2 is a sectional view in FIG. one.

The casing repair device contains a massive body 1. On case 1 with a gap 2, there is a plaster held by end holders 3. The plaster is made in the form of a length of longitudinally corrugated pipe 4 with an adhesive-sealing coating 5 applied on both sides of the pipe 4. B A gap 2 of the device is placed a drive in the form of charge 6 of an explosive material. The housing 1 is lowered onto the cable 7, is made with channels 8 for the passage of flushing fluid.

The operation of the proposed device is based on the installation of a patch in the place of damage to the casing due to the complete and irreversible expansion of the corrugated pipe at the time of the explosion.

When carrying out repair and insulation works, the device on the cross-cable 7 is lowered into the required interval of the well bore. Upon reaching the required depth and stopping the device against the place of damage in the casing string, an explosion of charge 6 of explosive material is performed by a command from the surface of the earth. At the time of the explosion due to its energy, the longitudinally-corrugated pipe 4 spreads and is pressed into the walls of the casing being repaired. At the same time, the adhesive-sealing coating 5 provides a better sealing of the damage site of the casing and prevents the place of damage and the physical-physical patch from chemical corrosion in the course of their further service in aggressive conditions of the well. In this way, the integrity and tightness of the casing is restored at the point of damage.

After completion of the installation, the patch of the device body 1 on the wireline 7 is removed from the well and, if necessary, prepared for installation of the next patch.

Studies have shown that the placement of charge 6 of explosive material around the perimeter of gap 2 between the massive body 1 and the plaster provides the necessary direction of the explosion in the radial direction and reliable adhesion of the plaster to the repaired column. In order to provide a greater directivity of the blast energy in the radial direction, grooves can be made on the outer surface of the housing 1 for placing charges in them. The type and amount of charge 6 of the explosive material is established empirically.

As a charge, it is most expedient to use, for example, a hydroinsulated detonating cord, the segments of which are placed evenly along the perimeter of the gap 2 over the entire length of the adhesive. The number of cords installed in the gap 2 is chosen depending on the ratios of the internal diameter of the repaired casing of the average diameter of the repaired casing, the average diameter of the patch used and its thickness in the initial state.

For example, natural or synthetic unvulcanized rubbers can be used as an adhesive sealing coating. In this state, these rubbers have good plasto-elastic properties and are easily applied to the corresponding surfaces of the longitudinally-corrugated pipe.

Under the action of the pressure generated during the explosion, these rubbers fill all the defects in the casing and the gaps between the column and the plaster, and due to the thermal energy of the explosion in the presence of accelerators and vulcanization activators in the unvulcanized rubber, the plastoelastic rubbers become solid.

The above transition of rubbers to a solid state provides the plaster with a high resistance to the action of the aggressive environment of the well and abrasion resistance. The result is a strong adhesion of the patch to the casing and its sealing. In addition, the patch itself is reliably protected from the action of an aggressive environment and mechanical effects, such as occur when passing a patch of various technological equipment through the installation site.

The use of the proposed casing repair device makes it possible to increase the reliability of fastening metal patches by increasing the efficiency of the explosive energy and reducing the costs of tripping operations by reducing the piston effect.

Claims (2)

1. US Patent No. 3179268, cl. 166-14, published. 1965. 2. Levin, E. A. et al. Explosive packer for isolating the upper intervals. "Oil Household, 1977, No. 1, p. 52-54 (prototype).