What are the proven, probable, and possible reserves of crude oil?

Proven reserves are estimated based on existing data from producing wells or from fields with recognized geological features. These reserves are generally accepted as economically recoverable. Probable reserves, also known as “2P” reserves, are based on geological and engineering data extrapolated from known producing fields. There is a higher degree of uncertainty regarding these reserves than proven reserves, but they are considered economically recoverable too. Possible reserves, also known as “3P” reserves, are considered to be technically feasible to recover, but contain this highest degree of uncertainty. They are based upon extrapolation from limited information, and are much more speculative than proven and probable reserves. These reserves are generally not accepted as economically recoverable.