<p>A method of automatically picking up a drill bit off the bottom of an opening in a subsurface formation, comprises a) setting a predetermined level of differential pressure across a mud motor at which pickup of the drill bit is to be initiated; b) monitoring the differential pressure across the mud motor; c) allowing differential pressure across the mud motor to decrease to the predetermined level; and d) when the predetermined level is reached, automatically picking up the drill bit.</p>
申请公布号
EP2558673(A2)
申请公布日期
2013.02.20
申请号
EP20110769369
申请日期
2011.04.11
申请人
SHELL OIL COMPANY;SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ B.V.
发明人
EDBURY, DAVID ALSTON;GUERRERO, JOSE VICTOR;MACDONALD, DUNCAN CHARLES;NORMAN, JASON B.;ROGERS, JAMES BRYON;SITTON, DONALD RAY