Heterogeneities of Carbonate Ramp Reservoirs - Characterization and Modelling of a Shoal Outcrop Analogue (Mid-Triassic)

In order to improve the understanding of sedimentological heterogeneities on varies scales, from micro-scale thin section to macro-scale correlations, a joint project was initiated between the University of Tübingen (Germany) and ENI S.p.A. This outcrop study focused on the characterization and modelling of the largest and thickest wedge (wedge 3) of the Quaderkalk Formation. The Middle Triassic Quaderkalk Formation in SW Germany composed of four lithostratigraphic separated bioclast-rich wedges and represents an outcrop analogue for sub-seismic scale carbonate ramp reservoirs. Facies range from mud-rich, low-energy offshoal (non-reservoir facies) to bioclast-rich, high-energy shoal (potential reservoir facies), deposited on an epeiric carbonate ramp. Instead of a continuous facies belt, tens of kilometres-scale correlations indicate several separated high-energy shoal areas forming a shoal complex “mosaic”, which is controlled by a cycle architecture. Integrating all data of an intensive field study, two 3D facies models were produced: (1) a 30 × 30 km model to simulate the large-scale facies pattern and (2) a more detailed 10 × 10 km small-scale model to simulate internal shoal reservoir heterogeneities. The results highlight the importance of realistic geological, especially sequence-stratigraphic input in order to optimize the simulations of carbonate shoals.