Impact of Mineral Precipitation on Oil Production in the Paradox Basin: An Emerging Unconventional Field in Utah

ABSTRACT: This study investigates the impact of mineral precipitation on porosity and permeability, and ultimately, oil production in Utah's Cane Creek reservoir, a complex system within the Northern Paradox Basin. A compositional reservoir model was developed incorporating multiphase fluid flow, transport, mineral dissolution, and precipitation kinetics. The fluid model included methane through C7+, representing heavier hydrocarbons, along with CO2 and N2, reflecting the Paradox Basin's oil composition. Initial analysis determined the reservoir rock's mineral composition varied with depth: limestone, anhydrite, illite, halite, and quartz, using spectral mineralogical logs. The reservoir's acidic aqueous phase (pH 5.42), containing ions like Ca++, Mg++, and SO4-, influences mineral reactions. Simulations explored mineral precipitation's effect on porosity and permeability changes in both matrix and fractures. Fracture porosity decreased from 7.0% to 6.5%, and matrix porosity from 8.2% to 7.8%. These seemingly small changes significantly impact fluid flow. The study also examined the influence of initial water saturation on production using low (32%), base (58%), and high (65%) saturation scenarios. The results highlight the importance of considering geochemical reactions in reservoir models providing valuable insights for optimizing field development and enhancing oil recovery through advanced simulations and geophysical data integration.