Motor cooling and debris management during milling

Abstract

In the drilling of oil and gas wells, some fluid isolation valves may be stuck in a closed position and may need to be milled out. Provided are methods and systems to dissipate heat and remove cuttings and shavings generated during milling of these fluid isolation barrier. The methods may include conveying a milling tool into a borehole, wherein the milling tool comprises a motor, a gear box coupled to the motor; a pump coupled to the gear box, and a mill bit coupled to the pump, milling a fluid isolation barrier positioned in the borehole using the milling tool, wherein heat is generated at the mill bit and by the motor during the milling of the fluid isolation barrier, and removing at least a portion of the heat by pumping fluid past the motor and the mill bit using the pump.

Dependencies are inferred from the claim text.