Natural-gas processing at ambient conditions (i.e., pentane and heavier) are called "natural-gas condensate" (sometimes also called "natural gasoline" or simply "condensate"). Natural gas is called "sweet gas" when relatively free of hydrogen sulfide; gas that does contain hydrogen sulfide is called "sour gas". Natural gas, or any other gas mixture, containing significant quantities of hydrogen sulfide, carbon dioxide or similar acidic gases, is called "acid gas." Raw natural gas can also come from methane deposits in the pores of coal seams, and especially in a more concentrated state of adsorption onto the surface of the coal itself. Such gas is referred to
Natural-gas processing of three types of wells: crude oil wells, gas wells, and condensate wells. Natural gas that comes from crude oil wells is typically called "associated gas". This gas can have existed as a gas cap above the crude oil in the underground formation, or could have been dissolved in the crude oil. Natural gas from gas wells and from condensate wells, in which there is little or no crude oil, is called "non-associated gas". Gas wells typically produce only raw natural gas, while condensate wells produce raw natural gas along with other low molecular weight hydrocarbons. Those that are liquid