Ali Keihani - Master of Petroleum Engineering, Sharif University of Technology, Tehran, Iran,
Abdolkhalgh masoumi - Master of Petroleum Engineering, Sharif University of Technology, Tehran, Iran
C. Ghotbi - Department of Chemical and Petroleum Engineering , Sharif University of Technology, Tehran, Iran

One of the main problem associated with oil production is asphaltene precipitate in the reservoirs. In order to plan for EOR methods, production scenario, and selection of completion technology, it is necessary to study the initiation of asphaltene precipitation called onset. Since the experimental methods is not only so expensive and time consuming, but also the required materials are not available. Consequently, modeling approaches as a new methods are proper substitute for laboratory procedure. These methods need less costs and time and higher accuracy compare to the experimental investigation which are the advantageous of these methods. Computational operations for onset determination was implemented using computer programming which needs very short elapsed time. In this paper by appropriate equations of state selection, (EOS) it was tried to predict the onset of asphaltene formation in the oil reservoir. EOS was selected based on the specifications of available crude oil samples. For this purpose, the required parameter for EOS and also modeling process was determined according to the published experimental data and the onset of asphaltene was predicted. Moreover, effects of system pressure has been analyzed in defined system.

Asphaltene onset, precipitation, pressure, SRK, Temperature.