Abstract: A method of mechanically hot tapping petroleum equipment that contains a hydrocarbonaceous fluid in its interior by drilling an aperture in such equipment while employing cooling by cyclic drilling and/or refrigeration, the equipment drilling being carried out in a manner such that the temperature of the drill and material being drilled do not exceed a predetermined target temperature that is derived from the decomposition temperature, auto-ignition temperature, and like characteristics of the fluid present inside the equipment.