This paper presents the results of data collection, analysis, and integration to build a 3D geologic model of an outcropping leveed-channel complex. Data is from more than 120 standard measured stratigraphic sections, behind-outcrop drilling/logging/coring,
ground-penetrating radar and electromagnetic induction surveys, and 2D shallow seismic reflection acquisition. This leveed-channel complex, which is part of the Dad Sandstone Member of the Cretaceous Lewis Shale, Wyoming, consists of ten channel-fill sandstones, confined within a master channel. The complex is 67m (200ft.) thick, 500m (1500ft.) wide, and has a net sand content of approximately 57 percent. Individual channel-fills are internally lithologically complex, but in a systematic manner which provides a means of predicting orientation and width of sinuosity. Although it has not been possible to completely document the three dimensionality of this system, the 3D model that has evolved provides information on lithologic variability at scales which cannot be verified from conventional 3D seismic of subsurface analog reservoirs. This vertical and lateral variability can provide realistic lithologic input to reservoir performance prediction. An outcome of this study has been knowledge gained of the extent of manipulation required to obtain the spatially correct geometry and architecture of strata when integrating outcrop and shallow, behind-outcrop data sets.