Improved Fault Seal Analysis to Deliver More Realistic Simulation Models: Current Standard Approaches Versus Locally Calibrated Analysis

Harris, Simon D.¹; Freeman, Steve ¹; Knipe, Rob ^1
1 RDR Ltd, School of Earth Sciences, University of Leeds, Leeds, United Kingdom.

Currently the fault seal analysis workflows available to the industry tend to focus around applying the shale gouge ratio (SGR) algorithm (e.g. Yielding et al., 1997 and Yielding, 2002) to estimate fault clay content distributions, and then the fault permeabilities are predicted using a small number of standard fault clay to permeability transforms (e.g. Manzocchi et al., 1999 and Sperrevik et al., 2002). Finally, the fault transmissibilities are estimated by combing the estimated fault permeability with an estimated fault rock thickness. This thickness is typically inferred by assuming a linear relationship between fault throw and fault thickness. Although this geologically driven, sample calibrated approach is clearly a move in the right direction, the global application of single specific rules is probably inappropriate. Numerous cases are coming to light where the application of this general technique is providing poor history matches (e.g. Onyeagoro et al., 2008). There are a number of fundamental reasons why this should be the case. The limitations of this approach will be reviewed, the areas of applicability discussed and significantly improved techniques outlined. We focus on the flow-simulated responses generated by applying these techniques. Simple rules will be outlined that should help make the prediction and calibration process more straightforward.

AAPG Search and Discovery Article #90090©2009 AAPG Annual Convention and Exhibition, Denver, Colorado, June 7-10, 2009