1Faculty of Chemical and Petroleum Engineering, Sharif University of Technology, Tehran, I.R. IRAN
2Research and Technology Directorate, National Iranian Oil Company (NIOC), Tehran, I.R. IRAN
3Faculty of Chemical Engineering, Amirkabir University of Technology, Tehran, I.R. IRAN
Asphaltene instability is one of the major problems in gas injection projects throughout the world. Numerous models have been developed to predict asphaltene precipitation; The scaling equation is an attractive tool because of its simplicity and not involving complex properties of asphaltene. In this work, a new scaling model is presented to account for asphaltene precipitation due to gas injection at reservoir conditions. Extensive published data from literature have been used in model preparation. To check predictive capability of the equation, miscible gas injection experiments are conducted for a southwest Iranian oil reservoir. Experimental results show that methane injection has significant effect on asphaltene precipitation and direct effect of temperature is less severe than other parameters. In addition to the accuracy and simplicity, the proposed equation provides universal parameters which make this approach novel for evaluation of future gas injection projects when simple PVT data are available.
 Yang Z., Ma C.F., Lin X.S., Yang J.T., Guo T.M. Experimental and Modeling Studies on the Asphaltene Precipitation in Degassed and Gas-Injected Reservoir Oils, Fluid Phase Equilib.,157, p. 143 (1999).
 Srivastava R.K., Huang S.S., Dong M., Asphaltene Deposition During CO2 Flooding, SPE Prod. Facil., 14 (4), p. 235 (1999).
 Jamaluddin A.K.M., Joshi N., Iwere F., Gurpinar O., An Investigation of Asphaltene Instability under Nitrogen Injection, Paper SPE 74393, Presented at the SPE International Petroleum Conference and Exhibition, Mexico, 10-12 February (2002).
 Hirschberg A., De Jong L.N.J., Schipper B.A., Meyers J.G., Influence of Temperature and Pressure on Asphaltene Flocculation, Paper SPE 11202, Presented at the SPE 57th Annual Technical Conference and Exhibition, New Orleans, LA, 26-29 September (1988).
 Monteagudo J.P., Lage P.L.C., Rajagopal K., Towards A Polydisperse Molecular Thermodynamic Model for Asphaltene Precipitation in Live Oil, Fluid Phase Equilib., 187–188, p. 443 (2001).
 Pazuki G.R., Nikookar M., A Modified Flory-Huggins Model for Prediction of Asphaltenes Precipitation in Crude Oil, Fuel, 85, p. 1083 (2006).
 Pazuki G.R., Nikookar M., Omidkhah M.R., Application of a New Cubic Equation of State to Computation of Phase Behavior of Fluids and Asphaltene Precipitation in Crude Oil, Fluid Phase Equilib., 254, p. 42 (2007).
 Nikookar M., Pazuki G.R., Omidkhah M.R., Sahranavard L., Modification of a Thermodynamic Model and an Equation of State for Accurate Calculation of Asphaltene Precipitation Phase Behavior, Fuel, 87, p. 85 (2008).
 Mofidi A.M., Edalat M., A Simplified Thermodynamic Modeling Procedure for Predicting Asphaltene Precipitation, Fuel, 85, p. 2616 (2006).
 Vafaie-Sefti M., Mousavai-Dehghani S.A., Mohammad-Zadeh M., A Simple Model for Asphaltene Deposition in Petroleum Mixtures, Fluid Phase Equilib.,206, p. 1 (2003).
 Vafaie-Sefti M., Mousavai-Dehghani S.A., Application of Association Theory to the Prediction of Asphaltene Deposition: Deposition Due to Natural Depletion and Miscible Gas Injection Processes in Petroleum Reservoirs, Fluid Phase Equilib.,247, p. 182 (2006).
 Soulgani B.S., Rashtchian D., Tohidi B., Jamialahmadi M., A Novel Method for Mitigation of Asphaltene Deposition in the Wellstring, Iran. J. Chem. Chem. Eng.,29, (2010).
 Leontaritis K.J., Mansoori G.A., Asphaltene Flocculation during Oil Production and Processing: A Thermodynamic Colloidal Model, Paper SPE 16258, Presented at the SPE International Symposium on Oil Field Chemistry, San Antonio, TX, January (1987).
 Escobedo J., Mansoori G.A., Theory of Viscosity as a Criterion for Detection of Onset of Asphaltene Flocculation, Paper SPE 28729, Presented at the SPE International Conference and Exhibition of Mexico Field, Veracruz, 10-13 October (1994).
 Wang S., Civan F., Productivity Decline of Vertical and Horizontal Wells by Asphaltene Deposition in Petroleum Reservoirs, Paper SPE 64991, Presented at the SPE International Symposium on Oilfield Chemistry, Houston, Texas, 13–16 February (2001).
 Pan H., Firoozabadi A., A Thermodynamic Micellization Model for Asphaltene Aggregation and Precipitation in Petroleum Fluids, SPE Prod. Facil., 13, p. 118 (1998).
 Pan H., Firoozabadi A., Thermodynamic Micellization Model for Asphaltene Precipitation Inhibition, AIChE J., 46, p. 416 (2000).
 Zahedi G., Fazeli A.R., Hosseini S.M., Pazuki G.R., Sheikhattar L., Prediction of Asphaltene Precipitation in Crude Oil, J. Pet. Sci. and Eng.,68 (3-4), p. 218 (2009).
 Speight J.G., Wernick D.L., Gould K.A., Overfield R.E., Rao B.M.L., Savage D.W., Molecular Weight and Association of Asphaltenes: a Critical Review. REVUE DE L'INSTITUT FRANÇAIS DU PÉTROLE, 40, p. 51 (1985).
 Andersen S.I., Pedersen C., Thermodynamics of Asphaltene Stability by Flocculation Titration, AICHE National Spring Meeting, 14-18 March (1999).
 Rassamdana H., Dabir B., Nematy M., Farhani M., Sahimi M., Asphalt Flocculation and Deposition. I. Then Onset of Precipitation. AIChE J., 42, p. 10 (1996).
 Rassamdana H., Sahimi M., Asphalt Flocculation and Deposition: II. Formation and Growth of Fractal Aggregates, AIChE J., 42, p. 3318 (1996).
 Hu Y.F., Chen G.J., Yang J.T., Guo T.M., A Study on the Application of Scaling Equation for Asphaltene Precipitation, Fluid Phase Equilib., 171, p. 181 (2000).
 Ashoori S., Jamialahmadi M., Muller-Steinhagen H., Ahmadi K., A New Scaling Equation for Modeling of Asphaltene Precipitation, Paper SPE 85673, Presented at the SPE International Technical Conference and Exhibition, Nigeria, 4-6 August (2003).
 Bagheri M.B., Mirzabozorg A., Kharrat R., Dastkhan Z., Ghotbi C., Developing a New Scaling Equation for Modeling of Asphaltene Precipitation, Canadian International Petroleum Conference (CIPC), Calgary, Alberta, Canada, 16-18 June (2009).
 Novasad Z., Costain T., Experimental and Modeling Studies of Asphaltene Equilibria for a Reservoir under C02 Injection, Paper SPE 20530, Presented at the 65th Annual Technical Conference and Exhibition, New Orleans, LA, 23-28 September (1990).
 Takahashi S., Hayashi Y., Yazawa N., Sarma H., Characteristics and Impact of Asphaltene Precipitation during CO2 Injection Sandstone and Carbonate Cores: An Investigative Analysis through Laboratory Tests and Compositional Simulation, Paper SPE 84895, Presented at the SPE International Improved Oil Recovery Conference, Kuala Lumpur, 20-21 October (2003).
 Hu Y.F., Lib S., Liu N., Chu Y.P., Park S.J., Mansoori G.A., Guo T.M., Measurement and Corresponding States Modeling of Asphaltene Precipitation in Jilin Reservoir Oils, J. Pet. Sci. and Eng., 41, p. 169 (2004).
 Negahban S., Bahamaish J.N.M., Joshi N., Nighswander J., Jamaluddin A.K.M., An Experimental Study at an Abu Dhabi Reservoir of Aspaltene Precipitation Caused by Gas Injection, SPE Prod. Facil., May, p. 115 (2005).
 Idem R.O., Ibrahim H.H., Kinetics of CO2-induced Asphaltene Precipitation from Various Saskatchewan Crude Oils during CO2 Miscible Flooding, J. Pet. Sci. and Eng., 35, p. 233 (2002).
 IP-143/90-ASTM D3279-90, Standards for Petroleum and its Products, Institute of Petroleum, London, p. 143.1 (1985).
 Verdier S., Experimental Study and Modeling of Asphaltene Precipitation Caused by Gas Injection, Ph.D. Thesis, Technical University of Denmark, (2006).