Reservoir Characterization Through Facies Analysis of the Lower Green River Formation for Hydrocarbon Production Enhancement in the Altamont-Bluebell Field, Uinta Basin, Utah

Ann Garner

Facies relationships of the lower Green River Formation in the Altamont-Bluebell field have not been sufficiently delineated as to enable operators to accurately target potentially productive zones. Consequently, completion techniques over the past 30 years have been applied to extensive intervals in a "hit or miss" fashion.

Research is being conducted in the Willow Creek Canyon area to establish the facies heterogeneity and reservoir storage capacity of lithology within the facies belts that have been defined in the Altamont-Bluebell field. Although production primarily occurs from fractured lithology, core plug analysis of more than 10 lithology indicates that arenites have the greatest potential for reservoir capacity, with porosities as high as 27%. This suggests that the association of arenites with fractured lithology would provide the best scenario for long-term production. X-ray diffraction has been used to establish clay type, percent content and potential effect on reservoir performance. The measured section was analyzed both visually and by Markov Chains for the occurrence of repetitive and cyc ic lithology, resulting in scales of cyclicity that range from seasonal to Milankovitch periodicities.

The results of this research can be combined with current and future studies of the fracture porosity that exists in this field. This will help operators better determine which specific zones they need to perforate and which completion techniques would most effectively maximize hydrocarbon production. This research can also be used to identify those zones that are potential targets for horizontal drilling.

AAPG Search and Discovery Article #91020©1995 AAPG Annual Convention, Houston, Texas, May 5-8, 1995