BOP Stack 3 : Blowout preventers-blowout preventer stacks - are assemblies of heavy duty valves attached to wellheads to control well pressure and prevent a blowouts
EESiFlo North America, Terminology and Glossary: Oil Well Terms, Pennsylvania, Oil: Oil Well Drilling Science and Technology, USA 2002, flowmeterdirectory.com/flowmeter_terminology, (Oil Well Drilling Sci and Tech - Amer) {555}