In this project funded by the Norwegian Research Council we have cooperated with CIPR at the University of Bergen on developing a concept for 3D modeling of the fault zone.
The fault facies concept means modelling a volumetric fault zone instead of populating a fault plane with fault transmissibility multipliers. In traditional fault modelling a transmissibility multiplier is assigned the flow simulation grid at cell faces co-located with the fault plane. The multipliers contain values depending on i.e. the shale ratio. The fault facies concept is a fundamentally different concept as it considers the fault as a volumetric object, called a fault zone. The properties of that fault zone will be dependent on both the pre-faulted properties and the strain causing the fault. Due to the deformation in the faulting process, these properties will be changed more at the centre of the fault than at the distal part of the fault zone. The fault rearranges the sedimentological behaviour such that an original lateral preferring anisotropy is tilted along the fault dip. This means that for a vertical flow, the vertical properties will typically be more favourable for flow than along one lateral axis. Thereby, a vertical flow within the fault is ensured. This behaviour is geological justified, and can for the fault plane concept only be ensured by allowing non-neighbouring flow contacts on the simulation grid.
Permeability without fault facies modeling Fault zone fine grid permeability Permeability in merged grid
Fredman, N., Tveranger, J., Cardozo, N., Braathen, A., Soleng, H., Røe, P., Skorstad, A., Syversveen, A.R.(2008) Fault Facies modeling: Technique and approach for 3-D modeling of faulted grids. AAPG Bulletin vol 92, pp1457-1478
Syversveen, A.R., Skorstad, Soleng, H., A., Røe, Tveranger, J. (2006) Facies modeling in fault zones. In Exmor X. Proceedings from the 10th European Confererence on Methematics in Oil Recovery. ISBN 978-90-73781-47-4