3P = Proven P90 + Probable P50 + Possible P10 2P = Proven P90 + Probable P50 1P = Proven P90 Probable P50 Possible P10 Proven Developed Reserves(PD) Proven Undeveloped Reserves (PUD)
See also Russian Hydrocarbon Reserves Uncertainty Categories.
See Also
Petroleum Industry / Upstream / Subsurface E&P Disciplines / Petroleum Geology / Petroleum Reservoir / Hydrocarbon Reserves / Hydrocarbon Reserves Classification