CONTINUOUS CIRCULATION DRILLING METHOD.

摘要

A coupler and a method for continuously circulating a drilling fluid through a drill string while adding or removing tubulars has a lower fluid pressure seal adapted to engage a drill string; lower grips adapted to engage a drill string; a valve positioned above said lower grips; upper grips adapted to engage a tubular to be added to or removed from said string; and an upper fluid pressure seal adapted to engage said tubular.