Blowout Preventer 7 : The equipment installed at the wellhead to control pressures in the annular space between the casing and drill pipe or tubing during drilling, completion, and workover operations. See also: Christmas Tree
EESiFlo North America, Terminology and Glossary: Natural Gas Terms, Pennsylvania, USA 2002. flowmeterdirectory.com/flowmeter_terminology, (Nat Gas - Amer) {569}