Mobina Mohammadi - Department of Petroleum Engineering, Petroleum University of Technology, Ahwaz, Iran
Riyaz Kharrat - Department of Petroleum Engineering, Petroleum University of Technology, Ahwaz, Iran
Abdonabi Hashemi - Department of Petroleum Engineering, Petroleum University of Technology, Ahwaz, Iran

Although the asphaltene problems have been studied for many years, there are numerous controversialissues around the nature of asphaltene. Since asphaltene precipitation imposes significant costs on oilindustry, a comprehensive research must be done to address the issues about asphaltene structures. Itis extremely important to investigate the behavior of asphaltene precipitation and ways to minimize itunder changeable effective thermodynamic factors such as pressure, temperature, and composition.In this work, natural depletion tests were performed at three different temperatures of 200, 170, and135 °F on Iranian heavy oil samples. At each step of the experiments, IP 143 standard test was used tomeasure the precipitated asphaltene. Then, a fuzzy logic model capable of predicting asphalteneprecipitation in a range of temperatures was developed. The fuzzy logic model predicts experimentaldata accurately. The obtained results were finally compared with a solid model using the commercialsoftware implementing the mentioned model, and it was concluded that there was good agreementbetween the fuzzy logic model and the simulation results.

Asphaltene Precipitation, Natural Depletion, Fuzzy Logic, Solid Model