Chemical cutter and method for high temperature tubular goods

In a downhole chemical cutting tool having an elongated tool body adapted to be inserted into a conduit and positioned at a downhole location thereof for effecting a cutting action in said conduit, the combination comprising:

• a) a chemical section in said elongated tool body containing a chemical cutting agent;
• b) a cutting section in said elongated tool body adapted to receive a chemical cutting agent from said chemical section;
• c) at least one cutting port in said cutting section for the discharge of chemical cutting agent therefrom;
• d) an ignitor mass comprising an accumulation of permeable ignitor material interposed between said chemical section and said cutting ports;
• and
• e) said ignitor material comprising an promoter component which is reactive with said chemical cutting agent in an exothermic chemical reaction at a first temperature and an ignitor component formed of a predominately non-ferrous, corrosion-resistant metal alloy which is reactive with said chemical cutting agent in an exothermic chemical reaction at a second temperature higher than said first temperature.

In a well penetrating into the earth from a well head to a subterranean location, the combination comprising:

• a) a tubular conduit within said well formed of a corrosion resistant metal having a greater resistance to corrosion than low carbon steel;
• b) downhole chemical fluid jet cutting tool within said well at a downhole location;
• c) a cable extending from the well head downwardly to said cutting tool and supporting said tool in said well, at said downhill location;
• d) means for raising and lowering said cable and said cutting tool within said well;
• e) said cutting tool comprising an elongated tool body;
• f) anchoring means in with said tool body for anchoring said tool at a downhole location in response to the application of fluid pressure and for releasing said tool body in response to the release of said fluid pressure;
• g) a chemical section in said tool body having a chamber therein adapted to containing a cutting fluid;
• h) a cutting section in said tool body having a longitudinally extending bore in fluid communication with said chemical section whereby upon the application of pressure to said chemical section, said chemical cutting agent is forced into said cutting section;
• i) a pressure generating section within said tool body within which pressure is generated to actuate said anchoring means and to displace said cutting agent into said cutting section;
• and
• j) a plurality of cutting ports in said cutting section for the discharge of chemical cutting agent therefrom extending transversely of the major axis of said elongated tool body;
• k) an ignitor mass comprising an accumulation of permeable ignitor material interposed between said chemical section and said cutting ports;
• l) said ignitor mass having an internal passageway within said accumulation of ignitor material extending between ports to facilitate flow from said chemical section to said cutting ports;
• m) said ignitor material comprising an ignitor component formed of a metal having a melting temperature in excess of 1600.degree. F. and a promoter component in contact with said ignitor component to facilitate the reaction of said ignitor component and said chemical cutting agent.

In a method of cutting tubular well goods at a downhole location within a well extending into the earth from a well head, the steps comprising:

• a) inserting into said well a chemical cutting tool having a chemical section containing a chemical cutting agent adapted to interact with a corrosion resistant tubular member in said well to form a cut in said tubular member and further having a cutting section adapted to receive said cutting agent from said chemical section;
• b) lowering said chemical cutting tool through said well to a desired location within said tubular member at which said cut is to be made;
• c) discharging said cutting agent from said chemical section into contact with an ignitor material to effect an exothermic pre-reaction of said chemical cutting agent, said ignitor material being formed in a permeable accumulation of a promoter component formed of a material which is reactive with said cutting agent in an exothermic reaction at a first temperature and an ignitor component formed of a metal interposed with said promoter component and which is reactive with said cutting agent in an exothermic reaction at a second temperature higher than first temperature;
• d) dispensing said pre-ignited chemical cutting agent from said cutting tool in a plurality of jet streams emanating from a plurality of cutting ports in the cutting section of said tool and into the contact with the inner surface of said tubular member to effect a cut in said tubular member.