The oil and gas industry has lot of data from different sources like wells and seismic surveys. By use of good statistical methods these data can be analyzed in a manner that can strongly support decisions-making. During planning, exploration and production of a field, many of the important decisions need to be taken under uncertainty. This includes positioning of new wells and different developments scenarios of fields. We incorporate data from large complex stochastic studies, many scenarios and parameter uncertainty to quantify the total uncertainty and thereby make it possible to compare different alternatives with respect to expected net present value or other crucial parameters.