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Eddie McAllister1, Rob Smallshire1, Rob Knipe1, Peter Kaufman2
(1) Rock Deformation Research, University of Leeds, Leeds, United Kingdom
(2) Schlumberger Doll Research, Ridgefield, CT

Abstract: Geometry of Fault Damage Zones from High Resolution Mapping of the Moab Fault Zone, UT

The geometry of a major normal fault zone has been mapped in an outcrop of medium coarse to fine grain dune bedded Jurassic sandstones at Bartlett Wash, Moab, UT. A complex array of inter-connected fault segments has been mapped in the exposed footwall of the Moab Fault Zone, using a high-resolution differential global positioning system. Significant advances have been made over the years to address the sealing potential of faults and fault damage zones, with the generation of extensive databases on the petrophysical characteristics and fault populations within fault zones. However, a major limitation has been the ability to capture the spatial organisation of the fault array, which forms the damage zones about faults. The use of high resolution GPS has provided a route to capture the true variation in the damage zone structure. This paper will present a three dimensional model of the Moab fault zone where we will demonstrate: 1. How the internal structure of a fault damages zone is organised. 2. The impact of sedimentary rheology on controlling the geometry of faults and the total damage zone width. 3. How the density of inter-connected faults vary with proximity to the main fault planes. 4. How the segmentation and geometry of faults within the damage zone vary. These results will be directly compared to both core and seismic data from dune sandstone reservoirs, and the ability to make predictive estimates of the damage zone structure from both core and seismic data illustrated.

AAPG Search and Discovery Article #90914©2000 AAPG Annual Convention, New Orleans, Louisiana