From Geomechanical Modelling to Seismic Imaging of 3D Faults
C. Botter, N. Cardozo, S. Hardy, I. Lecomte, A. Escalona, N. Cooke and G. Paton
Event name: 76th EAGE Conference and Exhibition 2014
Session: Geomechanics and Fracture Propagation
Publication date: 16 June 2014
Info: Extended abstract, PDF ( 2.78Mb )
Price: € 20
Faults are 3D narrow zones of highly and heterogenously strained rocks, with petrophysical properties differing from the host rock, and are primary controls on fluid flow in reservoirs. We present a synthetic workflow to assess the potential of seismic data for imaging fault structure and internal properties. The workflow is based on a discrete element model (DEM) of faulting, simple relations to modify the seismic properties based on volumetric strain, and a ray-based modelling (pre-stack depth migration or PSDM simulator). Parameters such as wave frequency and their impact on the resulting seismic image are evaluated with the PSDM simulator. We illustrate the application of the workflow to a large displacement 3D normal fault in an interlayered sandstone-shale sequence in two mdoels, one with constant fault slip and the second with linearly variable fault slip along strike. DEM produces realistic fault geometries and strain fields. Seismic cubes at a high wave frequencies show the complexity of the faults, with reflectors offset and laterally affected. As the wave frequency decreases the fault traces become simplier. Seismic extracted fault geobodies make a direct link between the seismic, the DEM and the internal properties of the faults.