The Late Cretaceous Mesaverde Fm (up to 600 m thick) exposed in the Wind River basin consists of a vertical and lateral mosaic of metre- to decametre-scale fluvial channels and associated interfluve facies. Detailed lateral mapping and measurements of the Mesaverde rocks from variously oriented outcrop faces reveals a two-fold architectural arrangement of channel geometries. The first consists of amalgamated channels (high density stacking) which form tabular sandstone bodies up to 50 m in thickness (lowermost Mesaverde and Teapot Mbr). The second is characterised by vertically and laterally isolated channel sandstones (low density stacking) encased in interfluve mudstone and thinner crevasse splay sandstones (middle member Mesaverde). This latter geometric style can be further categorised by apparent width:depth ratios and spatial connectivity of sandstone bodies as observed in outcrop. Detailing this changing fluvial style within the middle Mesaverde and determing the overall palaeogeographic controls on channel stacking thereby permits better evaluation of resevoir potential.

AAPG Search and Discovery Article #90928©1999 AAPG Annual Convention, San Antonio, Texas