Abstract: Petrophysical Characteristics of the Subsurface Sauk Sequence (Cambro-Ordovician) of Western New York

Mossbah M. Kolkas, Gerald M. Friedman

Petrographic analyses of selected core- and well-cutting samples from Niagara, Steuben and Wyoming counties, western New York, indicate that the Beekmantown Group (Sauk Sequence) was deposited in a shallow, tidally-influenced marine environment. Three major facies have been recognized: (1) sandstone, (2) sandy dolostone, and (3) dolostone. These facies have been divided into several lithofacies based on lithology, sedimentary microstructure, texture, and fabric.

Petrophysical analyses of some selected core plugs and well cuttings, using a mercury porosimeter, indicate that the sandstone facies has high quality reservoir parameters (porosity, recovery efficiency, and fluid saturation) compared to the other facies. Four types of capillary-pressure curves have been recognized from porosimetric studies: convex capillary-pressure curve (low porosity and high recovery efficiency), concave capillary-pressure curve (high porosity and low recovery efficiency), gently sloping capillary-pressure curve (intermediate porosity and intermediate recovery efficiency), and polymodal capillary-pressure curve (low porosity and low recovery efficiency). The petrophysical parameters (porosity, recovery efficiency, and fluid saturation) throughout the different lit ofacies are controlled by different degrees of diagenetic modification.

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