Unproved reserves are based on geologic and/or engineering data similar to that used in
estimates of proved reserves; but technical, contractual, economic, or regulatory
uncertainties preclude such reserves being classified as proved. Unproved reserves may
be further classified as probable reserves and possible reserves.
Unproved reserves may be estimated assuming future economic conditions different from
those prevailing at the time of the estimate. The effect of possible future improvements in
economic conditions and technological developments can be expressed by allocating
appropriate quantities of reserves to the probable and possible classifications.
