Harris, Simon1, Attila Vaszi1, Noelle Odling1, Rob
(1) Rock Deformation Research, Leeds, United Kingdom
ABSTRACT: Accurately Representing Complex Fault Damage Zones within Reservoir Models
A 3D stochastic fault damage zone (FDZ) model linked directly to a discrete fault flow model enables upscaled fluid flow properties of multiple realisations of regions of complex fault zones to be assessed for inclusion in reservoir simulators. The models are conditioned relative to the geometric factors that control the FDZ structure. The key parameters controlling the stochastic realisation of the FDZ and its efficiency at forming a connected retarder to fluid flow are the fault length–frequency relationship, orientation distributions, spatial clustering, fault/matrix permeability contrasts and fault thickness–throw relationships. The upscaled permeability of a region of the FDZ enables its efficiency as a fluid flow retarder to be characterised. Based upon stochastically-generated FDZ models, we can assess the influences of the flow and geometric parameters on the predicted 1D/2D/3D upscaled properties. In what situations is it essential to model the complete 3D flow and when can 2D flow provide adequate predictions? We address this question by ‘growing’ 2D regions into 3D. We can also determine the distributions of flow pathway lengths and fault rock thicknesses along flow pathways. Based upon a vast sequence of simulations through the above framework, a summary matrix is created which forms the basis for selecting appropriate input and a predictive/uncertainty tool to improve modelling of flow in fault damage zones in reservoir simulation models.
AAPG Search and Discovery Article #90026©2004 AAPG Annual Meeting, Dallas, Texas, April 18-21, 2004.