Butane 04 : A four carbon chain alkane, may be a liquid in the reservoir, but vaporizes as pressure is released. Part of the natural gas liquid components
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}