Field-scale Study on Carbon Dioxide Enhanced Oil Recovery-Storage in Residual Oil Zone

This study investigates the potential oil recovery and carbon storage of the residual oil zone (ROZ) in Illinois Noble Field Cypress Sandstone reservoir. Geological traits and oil-migration-resulted saturation are discussed, simulation reservoir model is then developed from scratch based on the selected geophysical logs. Afterwards, a reservoir simulation model is tuned and verified through the history matching of Cypress Sandstone formation production. Eleven different scenarios are performed beyond the waterflood phase, depending on variable CO2 availability scenarios and MPZ-ROZ development strategies. Several pivotal parameters reflecting EOR-storage performances, including cumulative oil recovery, CO2 storage, net CO2 utilization, oil production efficacy and CO2 storage efficacy are investigated to optimize the development strategy. ROZ oil production critical point (ROZ-OPCP) and ROZ opportune oil production trade-off point (ROZ-OOPTP) are defined as the criteria for development strategy evaluation. Results confirm that (1) volume of available CO2 significantly affects the choice of EOR-storage development strategy; (2) the development of ROZ is likely to be prolific and economically feasible under moderate and sufficient CO2 supply; (3) the project could benefit most from the sequential MPZ-ROZ development for the moderate CO2 supply case while the simultaneous MPZ-ROZ development from the beginning is favored for the sufficient CO2 supply case; (4) expansion to ROZ without considerable CO2 availability and opportune timing to the expansion could economically impair the project. In light of these results, a workflow for MPZ-ROZ reservoir development design is proposed. Ultimately, the study discusses several technical considerations for the EOR-storage project, including project lifecycle with efficacy, ROZ EOR-storage capacity appraisals, CO2 source and leakage, miscibility maintenance, saltwater procurement, and carbon storage taxation credits. Owing to the less versatility of compositional simulator and bulky simulation time, it is proven that regardless of the accuracy and consideration of CO2 dissolution in all phases, compositional simulator might not be the priority for field scale CO2-EOR reservoir study yet still is good to be used. Moreover, in terms of CO2-storage, since the E300 compositional simulator and CMG black oil solvent miscible model considered the dissolution/chemical reaction of supercritical CO2 in aqueous phase, which is commonly occurring during CO2 flooding, they are better options for CO2 storage estimation than E100 black oil simulator. Finally, this study provides sensitivity analysis on E100 black oil solvent miscible model by altering others key parameters like mixing parameter, transition control, gas/solvent saturation function, miscible saturation functions, solvent-gas residual saturation, pressure dependent miscibility function. Transferring the reservoir model constructed upon Petrel platform to CMG (IMEX) for further reservoir simulation would be effective, for utilizing both the former’s model construction capacity and the latter’s simulation model flexibility.