Proved reserves are estimated quantities of energy sources that the analysis of geological and engineering data demonstrates with reasonable certainty are recoverable under existing economic and operating conditions.
The location, quantity and grade of the energy source are usually considered to be well established in such reserves. Industry specialists refer to this as P90 (i.e. having a 90% certainty of being produced). Proved reserves are also known in the industry as 1P.
Operating conditions include operational break-even price and regulatory and contractual approvals, without which these items cannot be classified as proved and are usually classified as probable. Price changes can therefore have a major impact on the classification of proved reserves. Regulatory and contractual conditions may change, and may also affect the amount of proved reserves