Definition(s)
Kelly Swivel Valve (Kelly Cock or Upper Kelly Valve)
A valve located between the kelly swivel and the kelly, used for well control when the kelly is in the hole. It works like a check valve when engaged.
Source: API RP 54, Recommended Practice for Occupational Safety for Oil and Gas Well Drilling and Servicing Operations, Third Edition, August 1999 (2007). Global Standards
Kelly Cock
A valve immediately above the kelly that can be closed to confine pressures inside the drill string.
Source: API RP 59, Recommended Practice for Well Control Operations, Second Edition, May 2006. Global Standards
Kelly Cock (Kelly Valve)
Valves installed immediately above and below the kelly that can be closed to confine pressures inside the drill string.
Source: API STD 53, Blowout Prevention Equipment Systems for Drilling Wells, Upstream Segment, Fourth Edition, November 2012. Global Standards
Kelly Cock
Valve installed between the swivel and the Kelly to prevent high-pressure backflow. Closing the valve keeps pressure off the swivel and rotary hose.
Source: IADC UBO / MPD Glossary, December 2011. Global Standards
Kelly Cock
A valve installed at one or both ends of the kelly that can be used to confine pressure inside the drill string.
Source: Petroleum Safety Orders–Drilling and Production, Definitions, California Code of Regulations, 8 CCR § 6505, December 2012. Regulations