Idiosyncrasies of Cherokee Genetic Sequence of Strata, North-Central Oklahoma

James E. O'Brien

In plan view, the individual genetic increments of strata that comprise the Cherokee genetic sequence of strata are, for the most part, a complex maze of anastomosing fluvial channels generally trending north-south. This picture is further complicated by many isolated pods, splays, and partially preserved minor channels between and outside of the main channels.

When viewed in cross section, a few of the individual thick sandstone deposits (50-100 ft) are the result of a single depositional event. Most of these deposits are the result of the stacking of two or three individual channels. An additional complication occurs when downcutting into an underlying interval results in younger sandstones being stacked on older sandstones or occupying an interval that would appear to correlate with the older unit.

The rigid use of stereotype principles, such as type electric log signatures (e.g., bell shaped indicating a channel, inverted bell a bar, etc), unimaginative isopach contouring, computer generated data and/or maps, and scout card or other published information will yield erroneous interpretations. Electric logs need to be intelligently examined and interpreted. Numerous cross sections need to be constructed to show proper stratigraphic relationships. Well cuttings need to be examined microscopically. Isopach maps must be constructed with interpretive imagination, not by rote, in order to yield valid oil-finding interpretations.

AAPG Search and Discovery Article #91039©1987 AAPG Mid-Continent Section Meeting, Tulsa, Oklahoma, September 27-29, 1987.