Uncertainties: a Necessary Reflection of Our Understanding of the Subsurface – Embrace Them

Reservoir simulation and the process to forecast reservoir performance has evolved from early days over 40 years ago to a central role in the life cycle of oil and gas fields. The very high cost of offshore E&P put this technology at the heart of decisions that drive investments of billions of dollars in field development drilling and seafloor and topside facilities. This period has also seen the discovery and development of reservoirs of increasing geological complexity, and with it the fact that assumptions about reservoir properties away from well control carry significant uncertainty. The complexity and resource-intensive workflows typical of traditional reservoir modelling do not allocate sufficient preponderance to uncertainties and preclude rapid reactivity, othen resulting in a disappointing performance of high-cost assets. This paper covers the proper use of ensemble-based modelling as the solution to the industry’s need to de-risk large investments and make fact-based decisions in a constantly evolving environment.