A gas composed entirely of hydrocarbons.
Hydrocarbons– substance made of hydrogen and carbon (among other elements)
Grade through three states of matter: gases, liquids and solids. Petroleum exploration largely concerned with the fluids (gases and liquids).
Several specific forms of hydrocarbons-
- Dry gas– contains largely methane, specifically contains less than 0.1 gal/1000ft3 of condensible (at surface T and P) material.
- Wet gas– contains ethane propane, butane. Up to the molecular weight where the fluids are always condensed to liquids
- Condensates– Hydrocarbon with a molecular weight such that they are gas in the subsurface where temperatures are high, but condences to liquid when reach cooler, surface temperatures.
- Liquid hydrocarbons– commonly known as oil, or crude oil, to distinguish it from refined hydrocarbon products.
- Plastic hydrocarbons– asphalt
- Solid hydrocarbons– coal and kerogen- (kerogen strictly defined is disseminated organic matter in sediments that is insoluble in normal petroleum solvents.
- Gas hydrates- Solids composed of water molecules surrounding gas molecules, usually methane, but also H2S, CO2, and other less common gases.