Quantifying uncertainty in production forecast for fields with significant history

Understanding the effects of subsurface uncertainties on production responses is an integral part of the decision-making process. A more accurate quantification of the uncertainty of production forecasts contributes to better business decisions. When a field has produced for several years, models must be conditioned to available production data to obtain meaningful predictions. Data integration and uncertainty assessment of future performance of the reservoir are indivisible processes that cannot be addressed generally by simple techniques. A method is presented to solve complex inverse problems that involve highly nonlinear responses.