Chemical cutting apparatus and method for use in wells

摘要

A chemical cutting apparatus and method for cutting objects in well bores such as, for example, tubing in the bore of an oil or gas well. The apparatus is properly positioned relative to the object to be cut by means of a casing collar locator and an igniter is fired, which in turn activates a gas generator. Pressure from the gas generator axially displaces a slidable piston having one or more wedges pivotally connected thereto. Movement of the piston both pivots and extends the wedge, thereby bringing the wedge into contact with the object to be cut and anchoring the apparatus relative to the object to be cut. The pressure generated in the gas generator is communicated through a passageway in the slidable piston and forces a chemical cutting agent into a chamber containing a reactant. The reaction of the chemical cutting agent and reactant increases the pressure and temperature within the chamber thereby displacing along the axis a second slidable piston. Movement of the second slidable piston exposes radial exhaust orifices thereby allowing the reacting elements in the chamber to escape with great velocity and to contact the object to be cut.