Unconventional Resources : Hydrocarbon from unconventional and more difficult to produce resources such as (hydrocarbon): shale gas, shale oil, heavy and viscous oil, hydrates, tight gas, etc
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}