Complex Oolite Reservoirs in Ste. Genevieve Limestone (Mississippian) at Folsombille Field, Warrick County, Indiana

Charles W. Zuppann

Correlation of productive zones at the Folsomville field is difficult because lithology in the upper part of the Ste. Genevieve Limestone, which contains oolite bodies, is both laterally and vertically variable. The problem is further complicated by significant thickness variations of this interval that result in juxtaposed positions of porosity zones when geophysical logs are correlated side by side. Subsurface slice mapping, now an infrequently used method of subsurface analysis, can resolve complex geometries of oolite bodies and account for seemingly incongruous patterns of hydrocarbon production. Any mappable parameter can be envisioned in three dimensions by using the slice-map method. Net porosity and lithofacies slice maps, constructed at 2-ft intervals beneath a ersistent stratigraphic marker near the top of the Ste. Genevieve Limestone, describe the stratigraphic geometries of oolite reservoirs at the Folsomville field. Integrating fluid content and well-production histories with the slice maps allows patterns of hydrocarbon production to be deciphered, a procedure that should provide a valuable guide in designing the most effective enhanced recovery program for the field.

AAPG Search and Discovery Article #91023©1989 AAPG Eastern Section, Sept. 10-13, 1989, Bloomington, Indiana.