دیکشنری تخصصی مهندسی نفت - نسخه آنلاین

n: anyone of several types of valve installed in the drill stem or in a top drive to prevent highpressure fluids from flowing up the drill stem and into the atmosphere. Flow is possible only downward, allowing mud to be pumped in but preventing any flow back up the stem. Also called an internal blowout preventer.

n: A valve in the drillstring that may be used to prevent the well from flowing uncontrollably up the drillstring.

a valve installed inside the drill stem to prevent flow up the inside of the pipe.