Is It Still Necessary to Measure the Minimum Miscibility Pressure?

Abstract

Gas injection processes are among the most effective methods for enhanced oil recovery. A key parameter in the design of a gas injection project is the minimum miscibility pressure (MMP), the pressure at which the local displacement efficiency approaches 100%. From an experimental point of view, the MMP is routinely determined by slim tube displacements. However, because such experiments are very expensive (timeconsuming), the question we want to answer in this article is as follows: Is this still necessary to measure the MMP? In other words, may other quicker, easier and cheaper gas injection experiments such as swelling test or multicontact test (MCT) substitute for slim tube test? This paper concludes that when the injected gas is not pure CO 2 (and probably not pure N 2 or pure H 2 S), it is enough to fit only two parameters of the equation of state on data including classical PVT data + swelling data + MCT data and then to predict the MMP. The accuracy obtained is similar to the experimental uncertainty. It is thus possible to conclude that the slim tube test may be replaced by swelling tests and MCT, which are much cheaper.

Experimental and modeling study of the phase behavior of synthetic crude oil+CO2

“…(7) was 0.029 cm 3 or 0.13 % of the minimum cell volume. The extent of mechanical backlash was also considered by repeating calibration measurements at the same temperature and theoretical volume with the piston extending and retracting; the volumes were found to be repeatable to within ± 0.02 cm 3 , which is within the standard deviation of Eq. (7).…”

“…Figure 2 is an isometric view of the variable volume cell assembly. The cell was a horizontally-orientated cylindrical vessel of 26.5 mm internal diameter, 85 mm external diameter, and volume variable from (11 to 67) cm 3 . A blind axial hole in the vessel wall (5 mm diameter x 80 mm long) accommodated a Pt100 sensor for temperature measurements.…”

“…Phase behavior data are key inputs to reservoir simulations that are used for evaluating reservoir development plans, interpreting well test data, and designing surface facilities and processing plants [1]. Knowledge of the phase behavior of mixtures containing both CO 2 and hydrocarbons plays a major role in carbon capture and storage (CCS) and enhanced oil recovery (EOR) processes [2][3][4][5][6]. For example, the phase behavior of such systems is fundamental in the design of CO2-EOR projects in which the minimum miscibility pressure (MMP) for the CO2-crude oil system at the actual reservoir temperature is required in order to determine whether or not the CO2-flooding process will be immiscible or miscible at the actual reservoir pressure.…”

Integrating support vector regression with genetic algorithm for CO2-oil minimum miscibility pressure (MMP) in pure and impure CO2 streams

“…Generally, CO 2 can be injected as miscible or immiscible flooding but miscible flooding is far more effective than immiscible flooding for light and medium crude oil mostly because of the capillary pressure involved in multiphase flow in porous rock. The successful design and operation of CO 2 miscible flooding depends greatly on the so-called minimum miscible pressure (MMP) at which the local displacement efficiency may approach to 100% [4,5]. Consequently, accurate knowledge of CO 2 -oil MMP has become a key factor for CO 2 miscible flooding.…”

“…In the past 20 years, algorithms aimed at calculating the MMP from an equation of state (EoS) were developed [4,29,30]. Such approaches lead to accurate results when used with cubic EoS [31][32][33][34], but require a characterization procedure [35] and a deep knowledge on miscibility mechanisms [36] and critical phenomena [37].…”