CO₂ Storage with Mobility Control

The high mobility contrast between injected CO₂ and the formation brine at reservoir conditions makes the displacement efficiency low and can give early breakthrough of injected CO₂ into brine extraction wells for pressure management, or early reaching of spill points in structural traps. The storage capacity could in many cases be increased if efficient mobility control methods could be implemented for the injected CO₂. In this paper we investigate the potential benefits of mobility control for CO₂ injection in saline aquifers using both a commercial reservoir simulator and a specially developed module for the Matlab Reservoir Simulation Toolbox. The mobility control method investigated is surfactants for foam generation. These exists today both as water soluble and CO₂ soluble surfactants, and the efficiency of both types are studied. Rough estimates of the cost of additional storage capacity are made. Results show that the storage capacity in some cases can be more than doubled, at a cost the order of 7 $ per additional tonne of stored CO₂.