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
Billion cubic metres of natural gas Billion cubic metres of natural gas Billion cubic metres of natural gas (abbreviated: bcm) is a measure of natural gas production and trade. Depending of implied standards, this measure may represent different value of energy content. According to the standard defined by the International Energy Agency, it corresponds in average to of energy in the case of Russian natural gas and of energy in the case of Qatar's natural gas. According to the standard defined by the International Energy Agency, the gas physical volume is used, which is measured at the temperature of at atmospheric pressure. According to the Russian