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separated at the well site if natural gas pipelines are nearby or
flared as a waste. The produced water and other materials also are
typically separated from the crude oil at the well site. Petroleum
products are produced from the processing of crude oil at
petroleum refineries and the extraction of liquid hydrocarbons at
natural gas processing plants. Petroleum is a broad category term
that includes both crude oil and petroleum products, and is
sometimes used interchangeably with the term oil. Crude oil is
measured in barrels (one barrel equals 42 gallons).
About 85% of natural gas produced from conventional
wells is methane, a compound comprised of one carbon atom and
four hydrogen atoms. Ethane, propane, and butane also occur in
natural gas and are often separated and processed as natural gas
liquids. Natural gas exists as:
Associated gas in crude oil wells where natural gas exists
separate from the crude oil in the underground formation or is
dissolved in the crude;
Non-associated gas in dry gas wells that generally produce
only natural gas that does not contain any hydrocarbon liquids;
Wet gas (a type of non-associated gas) in condensate wells
where natural gas occurs along with natural gas liquid; and as coal
bed methane in coal seams.
Oil - viscous liquid from dark brown to light yellow color,
which is a mixture of methane, naphthenic and aromatic
hydrocarbons, resins asphaltenes, waxes and other inorganic
substances.
Natural gas - a mixture of methane series of hydrocarbons
with the general formula C nH 2n +2. The first 4 hydrocarbons
(methane, ethane, propane and butane) at atmospheric pressure and
standard temperature are in the gas state, and higher pentane (C5-
C17) - in the liquid (hydrocarbon condensate), C18 - and more - in
the solid state (paraffin).

Condensates
While the ethane, propane, butane, and pentanes must be
removed from natural gas, this does not mean that they are all
waste products. In fact, associated hydrocarbons, known as 'natural

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