Nothing about oil reservoirs is ever absolutely certain. The critical question from a business viewpoint is whether the lack of knowledge makes a difference to how we develop a reservoir, and if it does whether we can choose a development plan that minimises the impacts of that uncertainty. The group develops and applies mathematical models to quantify uncertainty in an oil reservoir. It does this using advanced mathematical and statistical techniques to blend different sources of information (including production data) to come up with a statistically consistent estimate of uncertainty. Optimisation techniques are then used to identify reservoir development plans (or interventions such as infill drilling) that maximise expected return and minimise risk in that return.