Swab Valve 3 : The valve at the top of the tree, above the flow cross or flow Tee. The lubricator for interventions may be attached above this valve or the valve may be removed to fit a larger lubricator
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}