Definitions, Sources and Explanatory Notes

 Category:   Crude Reserves & Production
 Topic:   Crude Oil and Lease Condensate Production by API Gravity


Key Terms Definition
API Gravity API gravity is the American Petroleum Institute's measure of specific gravity of crude oil or condensate in degrees. The measuring scale is calibrated in terms of degrees API:
                Degrees API = (141.5 / (sp. gr. 60ºF / 60ºF)) - 131.5
Barrel A unit of volume equal to 42 U.S. gallons.
Crude Oil A mixture of hydrocarbons that exists in liquid phase in natural underground reservoirs and remains liquid at atmospheric pressure after passing through surface separating facilities. Depending upon the characteristics of the crude stream, it may also include:
  • Small amounts of hydrocarbons that exist in gaseous phase in natural underground reservoirs but are liquid at atmospheric pressure after being recovered from oil well (casinghead) gas in lease separators and are subsequently commingled with the crude stream without being separately measured. Lease condensate recovered as a liquid from natural gas wells in lease or field separation facilities and later mixed into the crude stream is also included;
  • Small amounts of nonhydrocarbons produced with the oil, such as sulfur and various metals;
  • Drip gases, and liquid hydrocarbons produced from tar sands, oil sands, gilsonite, and oil shale.

  • Liquids produced at natural gas processing plants are excluded. Crude oil is refined to produce a wide array of petroleum products, including heating oils; gasoline, diesel and jet fuels; lubricants; asphalt; ethane, propane, and butane; and many other products used for their energy or chemical content.
    Crude Production The volume of crude oil produced from oil reservoirs during given periods of time. The amount of such production for a given period is measured as volumes delivered from lease storage tanks (i.e., the point of custody transfer) to pipelines, trucks, or other media for transport to refineries or terminals with adjustments for (1) net differences between opening and closing lease inventories, and (2) basic sediment and water (BS&W).

    For definitions of related energy terms, refer to the EIA Energy Glossary.


  • Form EIA-914, Monthly Crude Oil, Lease Condensate, and Natural Gas Production Report

  •   Explanatory Notes

  • Production volumes are for crude oil and lease condensate (combined), expressed in thousand barrels per day.
  • The sum of individual states may not equal total Lower 48 volumes due to independent rounding.
  • A zero may indicate volume of less than 0.5 thousand barrels per day.
  • Previous months' production volumes may have been revised for all states/areas.