A PROCESS FOR ESTIMATING GEOLOGICAL RISK OF PETROLEUM EXPLORATION PROSPECTS

Abstract

The concept of geological risk is critically important in petroleum exploration. It is distinct from both volumetric and commercia I risk. Geological risk is defined as the confidence that a proposed petroleum system is actually working at a particular prospect. Using knowledge-engineering techniques, BHP developed an improved scheme for assessing geological risk. The scheme expands the conventional breakdown of petroleum system elements to about fifty discrete factors, with individual confidence ratings being required for each. The ratings are combined into an overall geological risk using algorithms designed to emulate the typical judgements of experienced explorationists. In practice, application of the scheme also subjects each prospect to an extremely rigorous, detailed and objective review by a technical peer group, which has proved to be a valuable process in its own right. The methodology has improved the accuracy of pre-drill forecasting.