[M.D. Holloway]

Oil reserves are primarily a measure of geological risk - of the probability of oil existing and being producible under current economic conditions using current technology. The three categories of reserves generally used are proven, probable, and possible reserves.

Proven reserves - defined as oil and gas "Reasonably Certain" to be producible using current technology at current prices, with current commercial terms and government consent- also known in the industry as 1P. Some Industry specialists refer to this as P90 - i.e having a 90% certainty of being produced.

Probable reserves - defined as oil and gas "Reasonably Probable" of being produced using current or likely technology at current prices, with current commercial terms and government consent - Some Industry specialists refer to this as P50 - i.e having a 50% certainty of being produced. - This is also known in the industry as 2P or Proven plus probable.

Possible reserves - i.e "having a chance of being developed under favourable circumstances" - Some industry specialists refer to this as P10 - i.e having a 10% certainty of being produced. - This is also known in the industry as 3P or Proven plus probable plus possible.

The whole thing is a numbers game driven by speculation and margins. There are billions to be made and countries to control and for what it is worth we will not run out of oil for another 2000 years at the earliest.