Mini Review of Miscible Condition Evaluation and Experimental Methods of Gas Miscible Injection in Conventional and Fractured Reservoirs

Abstract

Nowadays, one of the most efficient ways of enhanced oil recovery (EOR) is gas miscible injection (GMI). In GMI, minimum miscible pressure (MMP) is the most substantial parameter. The MMP can be estimated by different methods, such as laboratory methods, using the equation of states (EOS), empirical correlations, mathematical models, and artificial intelligence. Among these, laboratory methods of estimating MMP comprise slim tube displacement (STD), rising bubble apparatus (RBA), vanishing interfacial tension (VIT), X-ray computerized tomography (CT), fast fluorescence-based microfluidic (FFBM) method, magnetic resonance imaging (MRI), sonic response method (SRM), rapid pressure increase (RPI), oil droplet volume measurement (ODVM), and pressure–composition diagrams (PCDs), all of which are described in detail in this paper. Furthermore, experimental investigations performed using the mentioned laboratory methods have been presented. On the other hand, to perform miscible injection experiments in the matrix–fracture system, there are methods, such as fractured core plug (FCP), matrix–fracture system (MFS), modified core holder (MCH), and microconsolidation device (MCD), that the accomplished studies by the mentioned method have surveyed. Eventually, it can be deduced that, owing to the difference between the MMP in conventional and fractured reservoirs, a reliable method (laboratory or mathematical model) for estimating the MMP in fractured reservoirs is required.