Middle Mississippian Stratigraphic Architecture along the Western Edge of the Outcrop belt in Northeastern Oklahoma - Analogs for the Distribution of Reservoir Facies and Trapping Mechanisms in the Subsurface

Cory Godwin, Darwin Boardman, Sal Mazzullo, Brian Willhite, James Puckette, and Michael Grammer

Occurrences of oil-bearing Middle Mississippian strata in the shallow subsurface and surface exposures along the western edge of the outcrop belt in northeastern Oklahoma serve as potential analogs for hydrocarbon exploration and production efforts targeting equivalent strata in the subsurface to the west. The distribution of reservoir facies and trapping mechanisms is primarily a function of a stratigraphic architecture that records a depositional and diagenetic history influenced by episodic tectonic uplift and the formation of regionally extensive unconformities. In this presentation we will discuss these stratigraphic controls and examine several examples that include: 1) An anomalously thick section of very coarse crinoidal packstone-wackestone in the Pierson Formation (Osagean) with zones of oil-staining. This facies is possibly associated with formation of carbonate mounds and is structurally up-dip from much thinner, non-oil-bearing Pierson. There is also an unconformity at the top of the Pierson Formation that potentially plays a role in entrapment. 2) Tripolitic and fractured chert in the upper Reeds Spring Formation (Osagean) associated with two regional unconformities. The older of the two occurs between the Reeds Spring Formation and overlying Bentonville Formation and is responsible for the diagenetic alteration of the the Reeds Spring chert and formation of the tripolite. The second unconformity occurs at the base of the Mayes Group and has stripped away all of the lower Meramec and upper Osage, as well as the tripolitic and fractured Reeds Spring chert in some locations. 3) Cherty dolomitic mudstone in the Reeds Spring Formation associated with a buried anticlinal structure beneath the sub-Hindsville Formation unconformity that has removed all of the Meramec and upper Osage. 

AAPG Search and Discovery Article #90176©AAPG Mid-Continent Meeting, Wichita, Kansas, October 12-15, 2013