Enhanced oil recovery (E.O.R) is oil recovery by the injection of materials not normally present in the reservoir. Thermal methods such as the steam injection process are the best heavy oil recovery methods. Improvement of mobility ratio in the reservoir and economic recovery from heavy oil reservoirs depend mainly on reduction of heavy oil viscosity. For a steam injection process should consider the heat and mass transfer.
Heavy oil reservoirs contain a considerable amount of hydrocarbon resources of the world. Meanwhile, further demand for oil resources in the world reduction of natural production from oil reservoirs, and finally price of oil in recent years have attracted notices to production methods from heavy and extra heavy oil reservoirs. High viscosity and great amounts of asphaltene in these hydrocarbons make difficulties in extraction, transportation, and process of heavy oil.
In Romania, there have been numerous theoretical and laboratory researches, as well as site experiments on the application of secondary recovery methods, Romanian specialists having a wide experience in this field