Abstract: Predicting Porosity Distribution within Oolitic Tidal Bars

Larry J. Cavallo, Jane Lew, Richard A. Smosna

The Mississippian Greenbrier Limestone is a major gas reservoir in the Appalachian basin, but its complex porosity patterns often deter active exploration. In southern West Virginia, the reservoir consists of oolitic tidal bars which are composites of smaller shoals. Porosity trends closely follow the ooid-grainstone facies which occupied shoal crests, where coarse-grained, well-sorted ooid sand was generated with either unidirectional or bidirectional cross-beds. Nonporous packstone occurred in adjacent tidal channels, and a transitional grainstone/packstone facies of marginal porosity was situated along the flanks of the shoals. The key to drilling successful wells is in understanding the complex internal geometry of Greenbrier

AAPG Search and Discovery Article #90950©1996 AAPG GCAGS 46th Annual Meeting, San Antonio, Texas