Shariatpanahi - Petroleum Engineering Department, Petropars Company, Tehran, Iran
Birang - Oil and Gas Center of Excellence, University College of Engineering, University of Tehran, Tehran, Iran
Dinarvand - Ahwaz Petroleum Engineering Faculty, Petroleum University of Technology, Ahwaz, Iran
Moghaddam - Pars Oil and Gas Company (POGC), Tehran, Iran

The objective of this study is to enhance recovery from one of the south Iranian oil reservoir through miscible gas injection. The Hydrocarbon reservoir gas was injected because of consistency between the gas and reservoir fluid composition and accessibility of the injected fluid in south of Iran. Engineering of miscible gas injection projects requires a collection of laboratory studies in order to properly comprehend the injection gas/reservoir fluid phase behavior. This article provides a complete set of miscible gas studies including PVT studies and slim-tube experiments. This suite of laboratory capabilities defines the miscibility conditions and minimum miscibility pressure (MMP) that are necessary to optimize recovery and production economics in miscible gas injection processes. In addition, Firoozabadi-Aziz correlation which is suggested to be applied for Nitrogen and hydrocarbon gases with methane content higher than 80 mole percent has been modified for wider range of oil and gas compositions to predict MMP. Also, by introducing two additional parameters in the driving gas, a new correlation is proposed for injection gases with methane content less than 80 mol%. Furthermore, by considering Iranian reservoir conditions a new correlation has been introduced. Average absolute deviation (AAD) for these correlations is compared with the experimental data. It has been shown that the results obtained from the new MMP correlations are more accurate when compared with the slim tube results.

Minimum Miscibility Pressure, Injection Gas, Mechanism of Miscibility, Miscible Displacement, Miscible Gas, Slim tube, PVT