Chemical cutting method and apparatus

Abstract

A downhold chemical cutting process for cutting a target object within a well. A source of a gaseous chemical cutting agent comprising a nitrogen fluoride is introduced into the well adjacent the target object and employed in a cutting operation in which the nitrogen fluoride cutting agent is directed against the target to the cut. A gaseous cutting agent source such as a mixture of florine and nitrogen trifluoride may be employed. Alternatively a perfluoroammonium salt which decomposes upon heating to produce a mixture of florine and nitrogen fluoride may be employed. A cutting tool comprising pressure actuated anchoring means, pressure generating and chemical sections, and a cutting section having a downwardly extending nozzle. The nozzle is provided with a standoff sleeve to provide a desired distance between the target object to be cut within a well bore and the nozzle outlet. A compound piston may be slidably disposed within the chemical section of the tool to prevent comingling between pressurizing fluid developed in the tool and a chemical cutting agent contained within the chemical section.