Lithofacies analysis of the Simpson Group in south-central Kansas

This book discusses detailed stratigraphy and lithofacies of the oil-productive Middle Ordovician Simpson Group in south-central Kansas. The report presents results of studies of the Simpson Group in Barber, Comanche, Kiowa, and Pratt counties. The high density of exploration holes and their associated logs allowed a detailed stratigraphic subdivision to be made of shale, sandstone, and sandy carbonate units. The lateral changes in these units are depicted in a series of maps and cross sections and show distinctive lithofacies patterns that reflect a history of northward-moving marine transgression. Working with digital data from gamma-ray logs, the geologists used computer methods to generate a series of cross sections of the Simpson Group, based on the statistical moments of the log traces. Automated mapping displayed the shapes and disposition of shale and non-shale units as continuous features in three dimensions. The ground truth information from drill cuttings further refined interpretations of stratigraphy, lithofacies, and depositional history implied by these computer models