Lithofacies, Sequence Architecture, and Petrophysical Characterization of the Lower Desert Creek Zone (Middle Pennsylvanian, Paradox Formation) in the Greater Aneth Field, Southern Paradox Basin, Utah

Abstract

The petroleum system of the Aneth Field in southwestern Utah is centered upon a 70 meter-thick, horseshoe-shaped carbonate buildup that covers approximately 140 square miles. Successive operators have studied the Aneth petroleum system over its 59-year history. Examination of tens of cores and over 200 well logs (made available by the Utah Geological Survey) permits development of sequence- and parasequence-scale facies maps across the breadth of the Aneth buildup. The Lower Desert Creek (LDC) interval of the Paradox Formation was deposited during a fourth-order glacio-eustatic sea-level cycle. Nucleated on top of the Akah interval, the LDC contains a thin (2-3 meter-thick) transgressive systems tract overlain by the TOC-rich Chimney Rock Shale. The superjacent highstand and falling stage systems tracts are comprised of up to 33 meters of normal marine carbonates arranged in 4 to 5 meter-scale parasequences. The eastern half of the buildup is dominated by phylloid algal reservoir facies. The depositional and diagenetic heterogeneities within individual LDC parasequences was evaluated by establishing a high-resolution stratigraphic framework-using core and log data. This facies architecture is derived from several hundred thin sections from across the buildup. The evolution of the LDC in the Aneth Field will be presented as a series of time slices reflecting field-wide sedimentological evolution of each systems tract. This study will provide a more in-depth sedimentological, sequence architecture, and petrophysical characterization of the Lower Desert Creek (LDC) of the Paradox Formation, as well as micro- and reservoir-scale heterogeneities through the LDC.

AAPG Datapages/Search and Discovery Article #90291 ©2017 AAPG Annual Convention and Exhibition, Houston, Texas, April 2-5, 2017