Reservoir management to enhance oil recovery, is always one of the concerns for the countries that have oil resources and each year vast sum of money is spent for research to enhance oil recovery. Owners of oil reserves try to get higher productivity from their own resources using new and less expensive methods. One of the most common methods of enhance oil recovery, is displacement of oil with gas injection. Injection of miscible gas is used to reduce or eliminate surface tension forces. On the other hand, most reservoirs of the Middle East region and also Iran are fractured reservoirs. Due to the matrix and fracture system which has different reservoir characteristics, fractured reservoirs are far more complex than conventional reservoir in prediction and simulation of fluid flow. Since typically the maximum amount of oil exists within the matrix, so we should use methods that can displace oil in the matrixes. One of the main methods for enhance oil recovery from fractured reservoirs is using gravity drainage mechanism within the matrix. In this case, injection of carbon dioxide as a miscible gas, is very effective as the low-pressure miscibility and providing a mechanism of gravity drainage and a significant increase in the ultimate recovery factor of this type of reservoirs.
In this project, we try to use the information of one of Iranian’s oil fields and then, by using the compositional model, the phenomenon of molecular diffusion effect on gravity drainage mechanism will be investigated. The results of the simulation shows, the importance of the phenomenon of molecular diffusion in the non-equilibrium gas injection into fractured reservoirs.
Keywords: Miscible gas, Gravity drainage, Compositional model, Molecular diffusion.
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Ringen, J.K., Haugse, V., Høier, L., Berge, L.I., and Reed, J. 2005. Experimental and Numerical Studies of Gas Injection in Fractured Carbonates: Pressure and Compositional Effects. Paper presented at the 2005 International Symposium of Society of Core Analysts, Toronto, Canada, 21–25 August.
Saidi, A.M. 1987. Reservoir Engineering of Fractured Reservoirs: Fundamental and Practical Aspects, 764–770. Paris: TOTAL Edition Press.
Saidi, A.M. 1996. Twenty Years of Gas Injection History into Well-Fractured Haft Kel Field (Iran). Paper SPE 35309 presented at the International Petroleum Conference and Exhibition of Mexico, Villahermosa, Mexico, 5–7
Stalkup, F.I. Jr. 1983. Miscible Displacement. Henry L. Doherty Monograph Series, SPE, Richardson, Texas, USA 8.
Uleberg, K. and Høier, L. 2002. Miscible Gas Injection in Fractured Reservoirs. Paper SPE 75136 presented at the SPE/DOE Improved Oil Recovery Symposium, Tulsa, 13–17 April. 118 Chapter 6.