Discussion on Validation of Calculated MMP from Correlation with Observed MMP from Slim-tube Experiment

Among existing enhanced oil recovery (EOR) processes, Injection of carbon dioxide (CO2) has been applied in a number of oil fields across the world. The popularity of CO2 as a miscible agent is due to its characteristics, which result in excellent macroscopic and microscopic efficiencies when miscibility conditions are optimal. One of the important parameters to consider when designing a miscible gas flooding project is the minimum miscibility pressure (MMP). MMP is defined as the threshold pressure to achieve miscibility in-situ between the injection gas and the reservoir oil. Since the MMP is a quick and convenient tool for conducting screening studies for post-evaluation of miscible projects, many correlations used to estimate the MMP have been developed for various crude oils and are presented in the literature. The problem is that not all correlations reflect the necessary process parameters needed in a typical CO2 flooding project. Correlations that work for reservoirs in Europe and America may not be suitable for reservoirs in the Iran. This paper addresses the issues related to experimental estimation of the MMP in the Iranian reservoirs and the evaluation of correlations as a means of estimating the MMP for a given reservoirs. The slim tube test has become a generally accepted procedure to measure the miscibility pressure. Another method uses theempirical correlations based on experimental results to predict the MMP. A predicted value can be significantly in error, however, especially if a correlation is applied at conditions far removed from the experimental conditions on which the correlation was based. In this paper, these correlations will be compared to each other with Observed MMP from Slim-tube Experiment of one specific Iranian reservoirs to see which predicted value is closer to the real value.

Keywords:

Enhanced oil recovery (EOR) , CO2 injection , Minimum miscibility pressure (MMP) , Empirical correlations , Slim-tube experiment