Big Clifty Sandstone Reservoir Characterization in Warren County Kentucky

Baizel, Linda; Butler, Kort; Reeder, Andrew; London, Jeremy; May, Michael T.

Renewed national and international interest has escalated exploration of unconventional or heavy-end hydrocarbons particularly in the southeastern Illinois Basin. Tar Sands (Asphaltic Sandstone), heavy oil and conventional oil typify resources within the basin that can be exploited at relatively shallow depths.

This study focuses on reservoir characterization of the Chesterian Big Clifty Sandstone and is based primarily on cores obtained during recent tar sand and heavy oil exploration. This investigation also relies on combined data sets from nearby outcrops, geophysical logs, and cuttings descriptions. Our work reveals details of a complex reservoir as is suggested by multiple oil-water contacts, and hydrocarbon staining controlled commonly from a micro- to macro-scale. Sedimentary structures such as bidirectional cross beds, contorted and overturned crossbeds, and ripple cross lamination specifically controlled the migration and emplacement of hydrocarbons as is evident from observation of stained and unstained areas of the core. Gamma Ray profiles of the core and offset wells suggest the Big Clifty is a well washed, clean quartz arenite. This is also corroborated by petrographic study of thin sections prepared from the cores.

We suggest that to fully exploit the Big Clifty, detailed petrographic analysis, sedimentary fabric characterization (micro and macro), and asphalt diffusion trends are required. Results obtained from this study can be applied to other tar sandstone formations within the region with some confidence. Further work on tar sandstone formations within the local region of the southeastern Illinois Basin can help to identify possible migration pathways, spatial distributions and producible volumes of economic significance.

AAPG Search and Discovery Article #90163©2013AAPG 2013 Annual Convention and Exhibition, Pittsburgh, Pennsylvania, May 19-22, 2013