Natural gas composed mainly of methane with only minor amounts of ethane, propane, butane, and minimum heavier hydrocarbons in the gasoline range.
Source: IADC UBO / MPD Glossary, December 2011. Global Stadandards
Any natural gas produced from a stratum that does not produce crude petroleum oil.
Source: Oil and Gas Division, Texas Administrative Code, Title 16, Chapter 3, February 2013. Regulations