--> Abstract: Stratigraphic and Depositional Controls on Fluid Migration through Eolian Sandstones - Comparing Outcrop with Reservoir, by Duncan, Katy and Richard Langford; #90071 (2007)

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Stratigraphic and Depositional Controls on Fluid Migration through Eolian Sandstones - Comparing Outcrop with Reservoir

Duncan, Katy1 and Richard Langford2
1El Paso Corporation E&P, Denver, CO
2University of Texas at El Paso, El Paso, TX

     The Cedar Mesa Sandstone is located in the Needles District of Canyonlands National Park, Eastern Utah, was deposited in an ancient sand dune sea, and is an exhumed stratum that has been a host for migration of and alteration by fluids. The Cedar Mesa Sandstone has a complex depositional history and consists of red and white interbedded and intertonguing cross bedded eolian, thin bedded fluvial, pebbly and muddy pedogenic, and thin, muddy and sandy, pond strata. The focus of the research was to characterize size, orientation, and lithologies surrounding small scale pond and associated pedogenic lithologies that act as permeability barriers in both outcrop and reservoir rocks. The Cedar mesa Sandstone is a useful analog for the Weber Sandstone that is a Permian aged producing eolian reservoir in the Rangely Field, Colorado. Comparisons were made between the outcrops of the Cedar Mesa Sandstone, and core and wireline log patterns through the Weber Sandstone. This revealed the two formations have similar dune and pond sizes and lithologies but different dune and pond orientations. We conclude that geometric distribution of groups of ponds stacked within sandstones is predictable using outcrop and log observations, along with wind direction, to reconstruct the depositional dune topography and accumulation. Predicting where large dunes are located in the subsurface may aid in the selection of drilling targets while avoiding permeability barriers.

 

AAPG Search and Discovery Article #90071 © 2007 AAPG Rocky Mountain Meeting, Snowbird, Utah