The Gothic Shale at Greater Aneth Oil Field, Paradox Basin, Southeastern Utah: Seal for Hydrocarbons and Carbon Dioxide Geological Sequestration

Thomas C. Chidsey, Jr., Stephanie Carney, Jason Heath, and Thomas Dewers

Presented at the American Association of Petroleum Geologists annual convention, Denver, Colorado, June 9, 2009.


Greater Aneth oil field, Utah’s largest oil producer, was discovered in 1956 and has produced over 451 million barrels (bbls) of oil. Located in the Paradox Basin of southeastern Utah, Greater Aneth is a stratigraphic trap producing from the Pennsylvanian Paradox Formation. Because it represents an archetype oil field of the western U.S., Greater Aneth was selected to demonstrate combined enhanced oil recovery (EOR) and carbon dioxide (CO2 ) sequestration. The Aneth Unit in the northwestern part of the field has produced 149 million bbls of the estimated 450 million bbls of OOIP—a 33% recovery rate. The large amount of remaining oil made the Aneth Unit ideal to demonstrate both CO2 storage capacity and EOR by CO2 flooding.