Mohammad Osat - Faculty of Fouman, College of Engineering, University of Tehran, Tehran, Iran
Mehdi Escrochi - Department of Petroleum Engineering, School of Chemical and Petroleum Engineering, Shiraz University, Shiraz, Iran
Masoud Riazi - Department of Petroleum Engineering, School of Chemical and Petroleum Engineering, Shiraz University, Shiraz, Iran
Seyed Hamed Mousavi - Faculty of Caspian, College of Engineering, University of Tehran, Tehran, Iran

Asphaltene precipitation and deposition is an important challenge facing petroleum industry. Three main factors i.e. change in temperature, pressure and composition could induce asphaltene precipitation. One of the most important concerns over deposition occurrence is tube plugging. In this study, we first measured the onset of asphaltene precipitation and then this process was examined at two different temperatures and finally two different n-heptane contents as precipitant for further consideration. Investigation of temperature effect on asphaltene precipitation have less been studied in previous researches. Therefore, it was decided that to consider the influence of temperature on the asphaltene precipitation in a capillary tube to achieve a better understanding about asphaltene deposition onto pipe lines surfaces. According to the results it was found that for flow in the tube with 0.04 cm inner diameter, 3.212 m length and with 12.5 ml/hr volumetric flow rate containing 60 Vol.% heptane, ∆P-∆P0 (excess pressure) varies but in a stochastic manner. It was shown in higher temperature i.e. 60 °C, the deposition occurrence was intensified and deposition onset has been brought forward. Moreover, for system containing 76 Vol.% heptane more deposition occurred as the level of ∆P-∆P0 in both temperature i.e. 30 and 60 °C has shifted to a higher level in comparison with system containing 60 Vol.% heptane as precipitant. Therefore, the simultaneous effect of higher temperature and more vol.% of precipitant agent resulted in a synergy that indicate the important role of factors involved in precipitation of asphaltene especially temperature in tubes. Result for temperature changes, in agreement with other works

Asphaltene, Deposition, onset point, temperature, capillary tube