| Analysis of published data, structure maps, isopach maps, well-log data, core data, and petrographic data suggest fair hydrocarbon potential for the Lower Ordovician may exist in the southern Michigan Basin.;The massive shallow-water Prairie du Chien carbonates are extensively eroded on the basin margins yet possibly are entirely preserved under transgressive marine St. Peter clastics in the central basin area. Both structural and stratigraphic traps exist in the southern Michigan Basin but may be difficult to explore for. Hydrocarbon migration distances may be variable. Favorable porosity and reservior potential may be found in association with viable traps, but will likely be limited in extent. Lower Ordovician hydrocarbons have been discovered in the southern Michigan Basin and surrounding areas but accumulations are generally small. Three possible hydrocarbon sources may exist within the 'dry gas and oil windows' including the Precambrian Nonesuch Shale, the upper Prairie du Chien, and the Middle Ordovician Utica Shale. |
