To Drill Or Not To Drill? Mature North Sea Field Case Study

Summary This paper shows the importance of uncertainty quantification for the mature small pool offshore field development. Mature small pool offshore field development is associated with high risks and high costs. Often projects in such fields are economically marginal therefore, the uncertainty quantification is very important to understand the full range of outcomes before making the ultimate decision on a given project. In this paper, we suggest an integrated workflow to account for a vast number of both static and dynamic uncertainties. To include the uncertainties into the project, we create an Uncertainty Matrix to group a huge number of uncertainties into a much manageable number of variables. In this work, we also address the challenges of capturing geological realism through facies modelling and propagating it whilst performing Uncertainty Studies. We demonstrate the application of the suggested workflow on a mature North Sea Brent Field with a limited data set. The subsequent results directly influence an infill well drilling decision on this field, which currently has two production wells and one injection well to date.