Contents lists available at ScienceDirect Fuel journal homepage: www.elsevier.com/locate/fuel Full Length Article Comparing the effects of CH 4 , CO 2 , and N 2 injection on asphaltene precipitation and deposition at reservoir condition: A visual and modeling study Peyman Zanganeh a,1 , Hossein Dashti b,1 , Shahab Ayatollahi c, ⁎ a Department of Chemical Engineering, School of Chemical Engineering, Shahid Bahonar University of Kerman, Kerman, Iran b Department of Chemical Engineering, School of Chemical and Petroleum Engineering, Curtin University, WA, Australia c Department of Chemical and Petroleum Engineering, Sharif University of Technology, Tehran, Iran GRAPHICAL ABSTRACT ARTICLE INFO Keywords: Asphaltene precipitation Enhanced oil recovery Carbon dioxide injection Nitrogen injection Methane injection ABSTRACT Enhanced Oil Recovery (EOR) through various methodologies has been an active research for many years seeking efficient methods to increase the crude oil recovery efficiency from oil reservoirs. Among different gas injection scenarios, carbon dioxide (CO 2 ), natural gas (mainly methane (CH 4 )) and nitrogen (N 2 ) injection are considered as promising EOR agents. Asphaltene precipitation and deposition during EOR methods cause severe problems, which affect the recovery efficiency and increase the cost of the incremental oil production. This study is aimed to investigate the effects of CH 4 and N 2 injection compared with CO 2 injection on asphaltene pre- cipitation and deposition. The different mole percent of the mentioned gases were introduced into the high- pressure cell, then the amount of precipitated asphaltene was measured at the reservoir condition. The evolution of asphaltene deposition was monitored through a high-resolution microscope. Moreover, Image processing software was utilized to check the amount of deposited asphaltene and its size distribution under different conditions. The most apparent finding to emerge from this study is that both CO 2 and natural gas increase the amount of precipitated asphaltene whereas the nitrogen as an inert gas has no considerable effect on the amount of precipitated asphaltene. According to the results, the increment of precipitated asphaltene by CO 2 is much higher than natural gas. Further, the thermodynamic solid model used in this study reasonably predicted the trend of asphaltene precipitation process for the mentioned EOR scenarios. https://doi.org/10.1016/j.fuel.2018.01.005 Received 11 April 2017; Received in revised form 21 December 2017; Accepted 3 January 2018 ⁎ Corresponding author. 1 The first two authors equally contributed to this work. E-mail address: shahab@sharif.ir (S. Ayatollahi). Fuel 217 (2018) 633–641 0016-2361/ © 2018 Elsevier Ltd. All rights reserved. T