ABSTRACT At this study natural depletion, associate and CO2 gas injection were comprised in aspect of asphaltene precipitation and permeability reduction. Core flood and asphaltene static apparatus were used to achieve these goals. Natural depletion was performed at 4500, 3050, 2250, 1450 and 900 Psig with asphaltene static apparatus and maximum amount of asphaltene precipitation was seen at saturation pressure. Then above saturation pressure natural depletion was done at same steps with core flood apparatus. It was concluded that asphaltene precipitation during natural depletion is higher than CO2 and Associate gas injection. Therefore oil trapping in natural depletion was more than associate and CO2 gas injection. . It was seen that rate of asphaltene precipitation in natural depletion is higher than CO2 and associate gas injection during time. Based on results, amount of asphaltene precipitation was differing according to type of gas. Asphaltene precipitation during CO2 injection is more than associate gas injection. Finally it was seen for this kind of carbonate the permeability reduction during associate was less than CO2 and gas injection and natural depletion.
