Improving underbalanced drilling using air in the Marcellus Shale

摘要

Underbalanced drilling with air has been popular in the Marcellus and Utica shale plays in the northeastern United States, because of high ROP and reduced formation damage as compared to conventional methods. In 2014, of the 111 rigs drilling in the Marcellus Shale, 27 rigs were drilling underbalanced and 23 were being drilled with air. A unique drilling system, incorporating the use of downhole mud motors, EM MWD, and air hammers, has been specifically designed and ruggedized to address downhole shock and vibrations encountered in air drilling. The use of this system has resulted in significant reduction of non-productive time (NPT) while drilling with air, plus increased ROP and reduced costs.