Mechanical Modelling and Seismic Imaging of Fault Zones
C. Botter, N. Cardozo, S. Hardy, I. Lecomte and A. Escalona
Event name: 3rd EAGE International Conference on Fault and Top Seals
Session: Geomechanical Modelling in Seal Evaluation
Publication date: 03 October 2012
Info: Extended abstract, PDF ( 756.46Kb )
Price: € 20
Faults are 3D zones of deformed rock that play a major role in controlling fluid flow in reservoirs. Fault zones are difficult to characterize: outcrops give limited view and seismic is limited by resolution and image quality. We propose an integrated approach to study fault zone evolution and its impact on seismic. We model fault zones using the discrete-element method (DEM). The finite strain of these models is used to condition seismic properties. Finally, seismic imaging of the DEM analogues is performed. An example is presented for a normal fault zone (60 m of fault displacement) in a 2D shale-sandstone layered model of size 1 x 0.5 km at 1 km depth. The fault zone has a complex distribution of shear and volumetric strain. Density, seismic velocities and reflectivities are conditioned by the volumetric strain of the DEM. Seismic imaging shows a response from the fault zone. Enhancing this part of the image is a challenge in acquisition and processing. Our approach can be extended to 3D. Future research will involve denser particles assemblages (smaller particles), and new techniques to pick much of the energy from the fault zone.