Minimum miscibility pressure (MMP) is an important parameter for assessing the applicability of miscible gas flooding for an oil reservoir. Slim tube studies have been routinely used for the purpose in the past. In the last decade, with the advent of the rising bubble apparatus (RBA), estimation of MMP by RBA for systems exhibiting vaporizing gas drives has become more common. However, the measurement by RBA for systems exhibiting condensing gas drive or enriched gas drive behavior has remained limited in the literature. This lack possibly arises from the difficulty in associating the observed bubble behavior for such systems with MMP value. This paper presents an interpretation technique for estimating MMP for systems which may not exhibit vaporizing gas drive behavior. This single bubble injection technique has been validated by comparing measured MMP results with a slim tube study and with an empirical correlation. It is also supported by values obtained for a multiple-bubble injection technique as suggested in literature and by consistency in results when the mechanism may change from vaporizing gas to condensing gas drive.
P. 553
