Chemical method and apparatus for perforating drill collars

Abstract

Discloses a method and apparatus to help provide fluid pressure in a well bore sufficient to overcome in situ earth formation pressures by perforating a circulation port through the sidewall of a drill collar above the drill bit to provide circulation of weighted drilling fluid down through the drill spring and back up the well annulus. Includes the lowering of a chemical reactant wireline perforating tool to a designated position within a drill collar, placing a single chemical flow jet into position addressing the sidewall of the drill collar, forcing the chemical reactant through the jet under high pressure and at high temperature to react with the drill collar metal and thereby remove a portion of the metal with the remaining metal defining a fluid circulation port through the drill collar wall, and pumping fluid through the port to establish circulation. Apparatus includes a tool body defining a single fluid flow jet, pressure actuated slips with the body to support the body against a vertical movement within the drill pipe, a body of chemical within the tool, a reaction section to heat the chemical, a pressure responsive decentralizing mechanism to position to the tool and thereby place the flow jet into position to direct the chemical directly onto the interior wall of the drill collar, and an electrically ignited propellant within the tool to set the slips, move the chemical through the reactant body, actuate the decentralizing mechanism, and force the chemical into reacting connection with the drill collar wall.