Measurement of Minimum Miscibility Pressure: A State of the Art Review
Birol Dindoruk, Russell T. Johns, Franklin M. Orr
Abstract
Abstract This paper gives a critical review of miscibility measurement techniques published in the open literature along with recommendations and lessons learned. Many of these suggested methods violate the assumptions for multicontact miscibility (MCM). The confusion often arises from a failure to distinguish between the first-contact miscibility (FCM), in which two fluids can be mixed in all proportions without forming two phases, and MCM, in which fluid compositions that arise during the flow of two phases in a porous medium approach a specific critical point within the constraints of the MCM definition. There are many analytical, numerical, correlational, and experimental methods available to estimate the minimum miscibility pressure (MMP) for MCM flow. The numerous available methods, some of which are quite inexpensive, have caused significant confusion in the literature and in practice regarding their ability to estimate MMP. Our experience has shown that the best methods are those that honor the multi-contact process (MCM), in which flow interacts with phase behavior in a prescribed way. Good methods that achieve this are slim-tube experiments, detailed slim-tube smulations, multiple mixing cell calculation methods, and the method-of-characteristics (MOC). Techniques such as the rising bubble apparatus (RBA) and vanishing interfacial tension (VIT) experiments are subject to significant uncertainties, though they may still provide quite useful information. Numerous MMP correlations have been developed. They should be used with caution for systems similarto those used to develop the correlation. Use for other systems can lead to significant errors. We discuss the advantages and disadvantages of most current methods and show that various combinations of methods can reduce uncertainty.