TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractThe objective of this study is to determine parameters that have major impact on the recovery from air injection into low permeable fractured chalk reservoirs that produce light oils, such as the Ekofisk field in the Norwegian North Sea.Earlier works on air injection into light oil reservoirs mainly focused on mathematical modeling of air injection and also on laboratory studies. In this paper, we present results from numerical simulation study.Results show that when recoveries from low permeability and high permeability reservoirs are compared, recovery is accelerated in the former. In addition, for maximum recovery, air should be injected into all layers containing hydrocarbons. The ultimate recovery from air injection was observed to be insensitive to the amount of water injected during the secondary recovery phase. Also, for optimum recovery, there exists a minimum temperature at which air should be injected, this temperature being a function of the injection rate. Lastly, we observed that residual oil saturation to gas does not have any significant effect on the recovery factor from air injection.These results are only valid for single porosity systems and may not all apply to dual porosity systems. Also, no economic analysis was undertaken in this study.