Patent ID: 6971449
Filing Date: 2005-12-06
Classification: E21B

Abstract:
1. An apparatus for cutting an opening through the wall of a metal conduit located in a borehole traversing the subsurface formations, comprising: a body adapted to be lowered into the metal conduit, said body comprising a surrounding wall defining an elongated chamber, a plurality of spaced apart outer apertures formed through said surrounding wall along a length thereof, said surrounding wall having an inner side and a central axis, a heat shield wall located next to said inner side of said surrounding wall along said length and surrounding an inner zone, a plurality of spaced apart inner apertures formed through said heat shield wall in alignment with said plurality of spaced apart outer apertures, wherein said inner and outer apertures are located in at least one elongated row which extends generally parallel to said axis, a combustible charge located in said inner zone, and an ignition means located in said chamber close to said inner zone for igniting said combustible charge for creating hot combustion products for passage through said inner and outer apertures for forming the opening through the wall of the metal conduit.