This research focuses on a novel concept, related to oil recovery from subterranean deposits. More specifically, we investigate methods for a rapid, in-field, non-destructive, specific and quantitative determination of oil and water content in cuttings or thick, intact cores taken from subterranean or underwater geological formations. The weight percentages of oil and water in the collected sample are determined using Fast-Neutron Resonance Transmission (FNRT) radiography or tomography. The method is suitable for all types of formations including tight shales, clays and oil sands. Monte-Carlo simulations and preliminary accelerator experiments pointed at the validity of the method, paving the way for further investigations.