Resumen del autor, extraido del trabajo. Casing Drilling™1 is an emerging technology for simultaneously drilling and casing a well where the casing is used to transmit mechanical and hydraulic energy to the bit, instead of using a conventional drillstring. A drilling assembly, positioned in the lower end of the casing, replaces the tools normally located on the lower end of the conventional drillstring. This assembly is retrieved with a wireline to access bits, motors, underreamers, MWD/LWD, and other components while leaving the casing in place. The Casing Drilling process has been used on portions of ten wells during a field trial phase. The system is still undergoing development but these wells have demonstrated the functionality of the casing drilling system.