Life cycle model for offshore installations for use in prospect evaluation

摘要

A life cycle model for offshore field development has been established as a compromise between a solvable model and at the same time a realistic model. Methods for optimisation of the life cycle model are discussed and a specific method is used in order to indicate the potential of utilising a life model in the design and optimisation of offshore developments. The improvement in Net Present Value, when using optimisation can be substantial. By example it was shown that the variation in net present Value between the individual viable development alternatives was roughly 50%, and thereby implied a significant potential in using optimisation. Most likely the real potential is less than this. The biggest gain in using optimisation is when it is applied at the borders of current technology, where the industry has a tendency to be conservative and adhere to proven technology. The potential of using a life cycle model and an optimisation method in exploration analysis was demonstrated. The results showed a large variation in profitibility between a stochastic analysis and a simple decision tree approach. This variation is caused by the stochastic methods consideration of nearly all possible development events as opposed to the simple decision trees consideration of only a few events. For a specific example the variation in expected net present value was in the order of 8 to 36%. It was demonstrated that a decision tree approach to exploration analysis fails the objective of a consistent approach by rejecting projects that actually could be commercially attractive and accepting non commercial projects, therby excluding the company from possible profits. (AB) (60 refs.).