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Abstract: Quantitative Studies of High Quality Outcrop Datasets: Examples from the Book Cliffs of Eastern Utah.

HOWELL, JOHN, PETE BURGESS, Stratigraphy Group, University of Liverpool, U.K.; GARY HAMPSON, University of London, U.K.; DIANE KAMOLA, University of Kansas; STEPHEN FLINT, and PETER STYLES, University of Liverpool, U.K.

Sequence stratigraphic and quantitative geometrical studies of high quality outcrop datasets remain one of the best methodologies for understanding reservoir architecture. However, their integration with standard geophysical techniques remains under exploited. A dataset includes a 120 km correlation panel through continuously exposed Cretaceous shallow-marine and coastal-plain deposits from the Blackhawk Formation, supported by over fifty wells and formed the basis for the studies discussed here. Empirical data collected during this study allow quantification of incised valley geometries and fill characteristics, shoreface progradational extents per systems tract and a deeper understanding of the nature of key stratigraphic surfaces.

Forward modelling of the quantified stratigraphic architecture enables the effects of altering individual controlling parameters, such as eustasy, tectonics or sediment supply, to be investigated. Using SMUT a purpose built geometrical modelling package, the stratal architectures described from the Book Cliffs were recreated, including the progradational parasequence stacking patterns and the detachment associated with documented lowstand deposits.

Construction of synthetic seismic sections allows simulation of probable seismic geometries from the known stratal architecture. Using sonic velocities from comparable facies within the Middle Jurassic Brent Group reservoirs of the North Sea, synthetic seismic sections for a variety of depths and porefluid types were generated. Special reference has been given to the potential for recognising the stratal terminations associated with incised valleys and the seismic expression of muddy lowstand shoreline deposits, detached from the main highstand wedge.

Thorough utilisation of outcrop datasets can enable predictive variations in architecture to be extracted from limited subsurface datasets, consequently reducing geological uncertainties.

AAPG Search and Discovery Article #90937©1998 AAPG Annual Convention and Exhibition, Salt Lake City, Utah