| 摘要 |
<p>In an aspect, an apparatus for use in a wellbore includes a tubular and a drilling assembly configured to carry a drill bit at an end thereof, wherein the drilling assembly is configured to be positioned within the tubular, wherein the tubular and drilling assembly are configured to be run in the wellbore together. The apparatus also includes an actuation device in the tubular configured to selectively extend the drilling assembly from and retract the drilling assembly into the tubular.</p> |
