A reservoir model

(a) For a new field development explain how a reservoir model, e.g. material balance, predicts parameters such as reservoir pressure, production rates of each phase (oil, water, and gas) and the estimated ultimate recovery of oil. Explain how the recovery factor could be maximised.
(b) Select two North Sea oil fields, one with a high recovery factor (> 65%) and one with a low recovery factor (< 20%) and explain in detail the key factors that have resulted in such reservoir performance.