Evaluation of Frac Sand Potential in Utah
Andrew Rupke and Taylor Boden
Utah Geological Survey
Demand for and production of frac sand (or proppant sand) has increased in the U.S. in recent years in response to the increased use of hydraulic fracturing to produce oil and gas. The source for much of the U.S. frac sand supply is the Midwest and the South, and production from the West is limited. Because transportation costs for frac sand can be a substantial percentage of the overall cost, a western source of frac sand could be beneficial to producers in western oil and gas fields. The Utah School and Institutional Trust Lands Administration provided the Utah Geological Survey with funding to investigate frac sand potential in Utah. For our study, a number of geologic units in Utah were examined and tested for their frac sand suitability including (but not limited to) Quaternary eolian deposits, Cretaceous Castlegate Sandstone, Jurassic Thousand Pockets Tongue of the Page Sandstone, Jurassic White Throne Member of the Temple Cap Formation, Jurassic Navajo Sandstone, and Permian White Rim and Cedar Mesa Sandstones. We gave priority to potential units that are relatively close to rail. Sieve analyses, roundness and sphericity evaluation, and semi-quantitative chemical analyses using XRF were performed at the Utah Geological Survey to evaluate frac sand suitability. We also noted friability of consolidated units during sample collection. Initial evaluation indicates that grain sizes from a few geologic units may be suitable for the 40/70 (ASTM sieve size) and 30/50 frac sand size designations. In most cases, the units with these favorable size fractions possess roundness and sphericity of the primary size fraction (most commonly material passing no. 40 and retained on no. 50) within acceptable limits. Semi-quantitative analyses also indicate relatively pure quartz sand in many samples, although some processing may be required to upgrade the purity to a marketable product. Preliminary results suggest the geologic units having the best potential are the White Throne Member; the Navajo, White Rim, and Cedar Mesa Sandstones; and some Quaternary eolian deposits. Although preliminary results indicate some potential, additional testing, particularly crush resistance, which measures the sand's strength to withstand downhole pressures, will need to be performed on potential deposits and geologic units.
AAPG Search and Discovery Article #90169©2013 AAPG Rocky Mountain Section 62nd Annual Meeting, Salt Lake City, Utah, September 22-24, 2013