CO2 injection has recently been shown to provide significant enhanced oil recovery from naturally fractured reservoirs 1 . Li et al. (2000) performed CO2 injection at 1750 psig on artificially-fractured cores after water flooding in a dead-oil system. Gravity drainage was suggested to be the dominant recovery mechanism in these tests, with significant tertiary oil recovery after water flooding. The authors observed that the recovery of initial oil at the start of the CO2 injection declined as the rock permeability decreased and the initial water saturation increased. Darvish et al. (2006) performed CO2 injection experiments on an outcrop chalk core.
