Abstract: The application ofThermal oilRecovery in reservoirs after waterflooding made the experts interesting at domestic and abroad. To determine the suitable reservoir conditions for steam injection, the effect of remaining oil saturation, formation thickness, heterogeneity and oilviscosity on the performance of steam injection inwater flooded reservoirwas studiedwith the reservoir
numerical simulation, and suitable reservoir conditionswere given in this paper. Remaining oil saturation afterwaterfloodingwas themain factor affectingwhether the waterflooding reservoir can be converted into steam injection. When the remaining oil saturation was not less than 0. 4, the waterflooding reservoir can be changed into steam injection. Using these reservoir conditions could basically be screened out the suitable reservoir afterwaterflooding converted into steam injection.

Key words: waterflooding reservoir, steam injection, thermal recovery, feasibility