This paper deals with optimal strategies for oilfield exploitation, taking into account the entire oilfield life cycle including exploration, appraisal, development, production and eventually abandonment. The two main sources of uncertainty are the size of the reserves, and the evolution of the oil price. We develop a model for the oilfield life cycle, including the major possible activities that may take place. This model is then analysed through stochastic control techniques to derive exploitation strategies that maximise a value function.