Milling apparatus and method for well casing

摘要

A well penetrator consists of a number of hydraulic fluid control components and a carriage carrying a hydraulic motor and a mill bit supported in a housing which is moveable down a well casing. The control components cause the carriage carrying the mill bit to be indexed up a predetermined distance relative to the well casing and then extended gradually into contact with the well casing while being rotated by the hydraulic motor. After the mill bit completes a hole through the well casing, the hydraulic components index the mill bit back down to its starting position and align a nozzle on the outer end of a high pressure lance with the opening in the casing to direct fluid from the nozzle as the lance is moved outwardly through the hole in the casing drilled by the mill bit.