I surely hope they are not stringing us along. So far I believe the team to be truthful.
P50 is a statistical median estimate of oil/gas reservoir size probability. Since oil and gas reservoirs are extremely difficult to size and accurately determine life and barrels per day a statistical approach is used.
Proved (P90): The lowest figure. It means that 90% of the calculated estimates will be equal or exceed P90 estimate.
Median (P50): This is the median.
Possible (P10): The highest figure, it means that 10% of the calculated estimates will be equal or exceed P10 estimate.
For example, if a geologists’ calculation estimates that there is a 90% chance that an oil field contains 50 million barrels and another estimate says there is a 10% chance of producing another 20 million barrels in addition to the 50 million barrels. So, we would refer to:
P10 as the highest figure – it is possible that we can produce up to 70 million barrels.
P90, the lowest figure – is it proved that we can produce up to 50 million barrels.