Dear Shakespare, dipak-m and cappy
Thanks, for the reply.
Additinally I have one more question. When reserves are calculated based on historical data like decline curve and based on production analysis data like WOR VS CUM PRODUCTION. It is my understanding that reserves based on these data/method should be categorised as P90. But I have seen cases where this resrves have been categorised as P50 specilly in cases where some investment decision was wanted. Please give your views. reservoirs have already produced more than 10 % of originally stipulated P50 Oil in Place.

Aquil