What type of reserve has about a 90% probability of estimates meeting cited value?

• A. Proved Reserves
• B. Probable Reserves
• C. Possible Reserves
• D. Contingent Resources

Answer: (A)

Proved Reserves are defined by a high level of confidence, using a P90 probability. That means there’s about a 90% chance that the actual recoverable quantity will be at least the cited value under current conditions and development plans. This makes Proved Reserves the most certain category, reflecting strong evidence of recoverability.

Probable reserves correspond to a lower confidence level (around P50), and Possible reserves to an even lower one (around P10), so they are less certain than Proved. Contingent Resources aren’t classified as reserves yet and depend on further development and certainty.