Offshore Minerals

Oil & Gas Terms and Definitions

API: American Petroleum Institute

bbl, Barrel: In the energy industry, a barrel is 42 U.S. gallons measured at 60ºF.

Casinghead Gas (or oil well gas): Natural gas produced along with crude oil from oil wells.

Condensate: A low-density, high-API gravity liquid hydrocarbon phase that generally occurs in association with natural gas. Its presence as a liquid phase depends on temperature and pressure conditions in the reservoir allowing condensation of liquid from vapor. The production of condensate reservoirs can be complicated because of the pressure sensitivity of some condensates. During production, there is a risk of the condensate changing from gas to liquid if the reservoir pressure drops below the dew point during production. Reservoir pressure can be maintained by fluid injection if gas production is preferable to liquid production. Gas produced in association with condensate is called wet gas. The API gravity of condensate is typically 50ºF to 120ºF.

Crude Oil: Liquid petroleum as it comes from out of the ground as distinguished from refined oils manufactured out of it.

Dry Natural Gas: See Natural Gas.

FPP or First Purchase Price (oil): The marketed first sales price per bbl of domestic crude oil, consistent with the removal price defined by the provisions of the Windfall Profits Tax on Domestic Crude Oil (Public Law 96-223, Sec. 4998 (c)).

mcf: One thousand cubic feet of natural gas measured at standard pressure and temperature conditions and obtained at the surface as such.

National Offshore: The total amount produced offshore in U.S. waters. State offshore totals and Federal OCS totals combined.

Natural Gas: A naturally occurring mixture of hydrocarbon and non-hydrocarbon gases in porous formations beneath the earth's surface, often in association with petroleum. The principal constituent is methane.

  • Dry gas- Natural gas that occurs in the absence of condensate or liquid hydrocarbons, or gas that has had condensable hydrocarbons removed.
  • Wet gas- Natural gas that contains less methane (typically less than 85% methane) and more ethane and other more complex hydrocarbons.

Outer Continental Shelf (OCS): The offshore Federal domain is greater than 3 miles from coastline for most states, beyond 3 nautical leagues from the Texas coast.

Pool: An underground reservoir containing, or appearing to contain, a common accumulation of oil or gas where each zone of a general structure completely separated from any other zone in the structure is covered by the term 'pool'.

State Waters Offshore: Offshore waters from 0-3 miles along a state's coastline except Texas, which extends up to 3 nautical leagues, or roughly 10 miles, out into the Gulf of Mexico.

Total Oil: Total liquids produced; crude oil and condensate combined.

Wellhead Price (Natural Gas): The value at the mouth of the well. In general, the wellhead price is considered to be the sales price obtainable from a third party in an arm's length transaction. Posted prices, requested prices, or prices as defined by lease agreements, contracts, or tax regulations should be used where applicable.

Wet Natural Gas: See Natural Gas.

updated 2-Oct-2012