Reservoir Characterization of the Mamuniyat Formation (Murzuq Basin, Libya) - An Integrated Approach from Core to Facies

The Mamuniyat Formation holds a number of producing hydrocarbon fields in SW-Libya. Its deposition is related to the Ordovician glaciation and thus inherits complicated stratigraphic and facies relationships. The study outlines a seamless workflow on the integration of core based facies analysis into a 3D reservoir model in this complex glacial environment. The workflow established in this study enabled the comingling of a high number of fluvial/deltaic to glacio-marine litho-facies into a susinct number of depositional environments which were then further refined into eight electro-facies categories which were able to be then effectively modelled. In essence the simplistic reservoir models produced captured all of the geological complexity as observed in core. A 3D facies model was developed from facies logs and constrained by seismic attributes and conceptual depositional environment maps. Fully fluvial environments (Upper Mamuniyat) and entirely marine environments (Lower Mamuniyat) were realized as classical object models. The interpreted transition from a coastal setting via shoreface into a marine setting in the Middle Mamuniyat was captured in a two step approach jointing Truncated Gaussian Simulation and object modeling. The resulting facies model is the base for property modeling, volume estimations and field development planning of the studied reservoir.