Recent advances in software and hardware technology have made possible the development of field-scale, fully compositional CO2-flood simulations capable of capturing areal variations in performance on an individual well basis. This paper first describes the general methodology developed, including key elements used to construct such large models, followed by the validation of this approach. Two modeling studies conducted on the Wasson Denver Unit are then presented to highlight several of the significant outcomes realized so far: high-grading the profitability of new CO2 projects, pinpointing best-well candidates to return to production, identifying infill and horizontal drilling locations, and identifying and quantifying injectant losses.