Fundamentals of Fluid Flow in Porous Media

Chapter 5

Miscible Displacement

Determination of Miscibility Condition

Determination of miscibility condition as the condition that miscibility is achieved during FCM or MCM process is very important for designing a miscible displacement process. Temperature, pressure and solvent injection composition are three major parameters that determine the miscibility condition. The temperature of the process is set by the reservoir temperature but the pressure could be changed in a certain interval as well as the injection solvent composition, so most of the methods have been designed to directly measure or predict the minimum miscibility pressure (MMP) or minimum miscibility enrichment (MME) at which miscibility will be achieved in a first or multiple contact process for a specific reservoir fluid composition and the reservoir composition.  There three different methods to predict the miscibility conditions (MMP or MME):

1. Experimental Measurements
2. Empirical correlations based on experimental results
3. Phase-behavior calculations based on an equation of state and computer modeling

While the experimental methods measure directly MMP and MME other ones predict these values.

Experimental Measurements

Experimental tests can be used for some specific studies such as oil vaporization by gas injection or evaluation and tuning of phase behavior models for numerical simulation of the reservoir performance. In this section determination of miscibility conditions (MMP or MME), using these methods, will be explained.