The early phase of the research conducted considerable reservoir and fluid characterization work and identified both technical and commercial challenges of producing the enormous quantities of water when flooding the ROZs. The Goldsmith-Landreth project in the Permian Basin was intended to first identify the most pressing issues of the ROZs floods and, more » secondly, begin to address them with new techniques designed to optimize a flood that commingled the MPZ and the ROZ.
But the nature of the formation and fluids within the ROZs has brought some challenges that were not present when flooding the MPZs. At least for the Permian Basin region of the U.S., the oil recovery has been now been extended into residual oil zones (ROZs) where the mobile fluid phase is water and immobile phase is oil. The technology for CO 2 Enhanced Oil Recovery (CO 2 EOR) has significantly advanced since the earliest floods were implemented in the 1970s. ROZs were originally identified and defined in the Permian Basin of West Texas but have since been identified or speculated in several geologic basins, including the Williston Basin and = , However, using CO 2 enhanced oil recovery (EOR), substantial amounts of oil can be recovered from ROZs while simultaneously storing CO 2. ROZs are naturally waterflooded portions of oil reservoirs with oil saturations between 25% and 40% but are at irreducible oil saturation levels with respect to water, rendering the reservoirs uneconomic using conventional recovery methods. Suspected ROZs identified by this approach were evaluated for their potential oil recovery using carbon dioxide (CO 2) and for associated CO 2 storage.
This approach models the evolution of a sedimentary basin to predict if, when, and where reservoirs were charged with hydrocarbons. The goal of this project by the Energy & Environmental Research Center was to systematically assess the petroleum systems of the Williston and Powder River Basins (PRB) for prospective residual oil zones (ROZs) through a geologic process modeling approach.