Previous experimental studies show that “nanoparticle-stabilized” supercritical carbon dioxide (CO2) foams (NP‐stabilized CO2 foams or NP CO2 foams in this paper) can be applied as an alternative to surfactant foams, to reduce CO2 mobility in gas‐injection enhanced oil recovery (EOR). The NPs, if chosen correctly, can be effective foam stabilizers attached at the fluid interface in a wide range of physicochemical conditions.
By using NP CO2 foam experiments available in the literature, this study investigates the applicability of NP foams for mobility control and, thus, improved sweep efficiency. This study consists of two tasks: (1) presenting how a population‐balance mechanistic foam model can be used to fit experimental data and determine required model parameters and (2) examining sweep efficiency in a condition resembling Lisama Field (a five‐spot pattern with four producers and one injector in the middle), by using relevant gas mobility‐reduction factors (MRFs) derived from the mechanistic‐modeling technique. The field‐scale simulations are conducted with Computer Modeling Group (CMG) software, contrasting NP and surfactant foams (in both dry and wet foam‐injection conditions) to a gas‐only injection and a gas/water coinjection (no foam).
The results show how the model can successfully reproduce coreflood experimental data, creating three different foam states (weak foam, strong foam, and intermediate) and two steady‐state strong‐foam regimes (high quality and low quality). When the gas-phase MRFs, ranging up to 10 from the model fit, are applied in the field‐scale simulations, the use of NPs improves oil recovery compared with a gas/water coinjection, but not as efficiently as a successful surfactant foam injection does. This implies that, although NP‐stabilized foams do provide some benefits, there still seems to be some room to improve the stability and the strength of resulting foams.