Downhole chemical cutting tool

Abstract

A downhole chemical cutting tool having an improved cutting section. The tool comprises an elongated tool body adapted for insertion into a well bore and includes anchoring means actuatable between a deployed position in response to the application of fluid pressure and a retracted position in response to the release of such pressure. The tool further includes a chemical section and a cutting section located in front of the chemical section. The cutting section has a longitudinally extending bore which is in fluid communication with the chemical section at the rear of the cutting section and in fluid communication with the exterior of the tool body at the front of the cutting section. The cutting section is provided with one or more cutting ports through which the cutting fluid passes when the tool is fired. A piston is slidably disposed in the bore of the cutting section at a location between the ports and the chemical section. When the tool is fired, the fluid pressure developed sets the anchoring means and forces the piston forward, exposing the port to the cutting fluid flowing into the bore from the chemical section. The tool further comprises means in the cutting section in front of the port to receive the piston upon the application of fluid pressure in the tool to lock the piston in place at a location in front of the cutting port. The locking means may take the form of a reduced section in the cutting tool bore which is adapted to receive a portion of the piston in a swedged relationship.