Mohammad Ali Karambeigi - Department of Chemical and Petroleum Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran.
Riyaz Kharrat - Petroleum Research Center, Petroleum University of Technology, Tehran, Iran.

Asphaltene precipitation due to EOR methods or natural depletion is a serious technical problem at petroleum industry. This paper presents the result of asphaltene precipitation during associated gas injection, CO2 injection and natural depletion in reservoir condition. In addition, the effect of variations in operation pressure, injection gas concentration and production rate on asphaltene precipitation and difference between slope of precipitation graph due to various method of EOR or natural depletion were investigated. The results revealed that temperature has an efficient role on result of associated gas and CO2 injection. By decreasing temperature, the amount of asphaltene precipitation due to associated gas injection was increased. In fact, recovery of gas injection was decreased at lower temperatures. Therefore solubility model has most effect on asphaltene precipitation.

Asphaltene Precipitation, Associated Gas Injection, CO2 Injection, Natural Depletion, Static Tests