Utah Bituminous Sandstone Deposits: the Good, the Bad and the Ugly

Steven Schamel
GeoX Consulting Inc, Salt Lake City, UT

Utah has the largest unexploited bituminous sandstone resources in the contiguous United States, an estimated 15-20 BBO. Virtually all previous investigations of the deposits have evaluated their suitability for surface mining and bitumen extraction. While the studies have highlighted the serious drawbacks of this recovery strategy, they point to the potential viability of targeted in-situ recovery methods. Factors that are encouraging for successful in-situ recovery are: a) substantial portions of deposits with grades in excess of 125 MBO/acre, b) bituminous-saturated sandstone units 60 to 150 ft thick, c) good porosities and acceptable permeabilities, and d) easily upgraded reservoired oils. The oil-water contact is unknown in several large deposits, which opens the possibility for larger resources than previously predicted and more easily exploited “water-wet” reservoirs at depth. Unfavorable factors include: a) high degree of reservoir heterogeneity, b) unusually high viscosities at reservoir temperatures, and c) overall low oil grades, generally less than 75 MBO/acre. Nearly all of the deposits are on public lands, most of which have high ecologic, recreational and scenic values that will preclude or seriously limit commercial-scale strip mining operations. The future for development of this valuable heavy and extra-heavy oil resource lies in the application of innovative in-situ recovery methods having minimal surface impacts.

AAPG Search and Discovery Article #90092©2009 AAPG Rocky Mountain Section, July 9-11, 2008, Denver, Colorado