Wellhead 12 : The mechanical connection between the tree and the casing. May house tubular hangers, annular access valves. It is connected to the casing by welding, threads, hydraulic forming or set screws
George E. King Engineering, 5000 Oilfield Terms: A Glossary of Petroleum Engineering Terms, Abbreviations and Acronyms, US 2010. http://gekengineering.com/Downloads/Free_Downloads /Glossary_of_Petroleum_Engineering_Terms_25_August _2010.pdf, (Oil - Amer) {593}