دیکشنری تخصصی مهندسی نفت - نسخه آنلاین

n: a valve installed at one or both ends of the kelly. When a high-pressure backflow occurs inside the drill stem, the valve is closed to keep pressure off the swivel and rotary hose. See lower kelly cock, upper kelly cock.

n: a valve installed between the kelly and the swivel,it is used to control a backflow of fluid up the drill string and isolate the swivel and hose from high pressure.

the valve on the Kelly.