Predicting OGIP reserves and facies analysis of the Lewis "E" Sand, Desert Springs Field, Green River Basin, Wyoming 

Jenny LaGesse, Colorado School of Mines, Department of Geology and Geological Engineering, Golden, CO, [email protected]

Within the Green River Basin of Wyoming, the Cretaceous Desert Springs field is one of the largest gas-producing fields.  The productive Lewis “E” sand is part of a series of turbidite sandstones with relatively high average porosity (16.7%) and permeabilities (7.9 md).  The reason for the relatively high-quality reservoir properties of the Desert Springs field is currently unknown.  This study should provide a more accurate estimate of gas-in-place reserves, structural and production limits, and a better understanding of reservoir facies characteristics for this field of significant regional importance.

Artificial neural networks will be used to generate synthetic porosity logs of the Lewis “E” sand where they are absent and be applied to OGIP calculations to improve gas estimates within the field.  While previous studies of the Lewis “E” sand reservoir used a single average porosity value for gas-in-place calculations, this study will predict porosity for each reservoir interval.  This will provide more accurate OGIP calculations of field reserves and create possibilities for further development of this field.