Applicability of methane foam stabilized via Nanoparticles for enhanced oil recovery from carbonate porous media at various temperatures

Over the 60 years of primary production from carbonate oil reservoirs in the middle east, approximately 30 % of initial oil in place has been recovered in this area and the rest requires appropriate enhanced oil recovery (EOR) methods for production. Since there are huge gas resources in this area, applications of gas-based EOR methods especially those with methane gas should be the top priority. Therefore, the objective of this study is to experimentally determine and compare the influences of stabled methane foams via aluminum oxide (Al2O3), titanium dioxide (TiO2), zinc oxide (ZnO), and silica (SiO2) nanoparticles (NPs) for EOR from a limestone porous medium at 25, 50 and 85 °C. For this goal, 0.1 wt% Sodium dodecyl sulfate (SDS) was dissolved in NaCl solution 0.5 wt% and then the above-mentioned nanopowders at concentrations from 0.005 to 0.1 wt% were added. Methane at a flow rate of 250 ml/min was injected into the suspensions and the stability of produced foams was defined by measuring the half-life time. Once an optimum concentration of each NP type was found, that foam was chosen to be flooded to the limestone porous medium for EOR purposes. The optimum NP content in terms of foam stability at all temperatures was achieved at 0.01 wt% for SiO2 and ZnO NPs and 0.05 wt% for TiO2 and Al2O3 NPs. Half-life time values of methane foams in the presence of NPs were averagely found to be 16 and 3 times higher than those of the base foam at 25 and 85 °C, respectively. TiO2, Al2O3, ZnO, and SiO2 NPs in order were the best additives for foam stability at all temperatures. In addition, at 85 °C, the incremental oil recovery amounts from the limestone porous medium by TiO2, Al2O3, ZnO, and SiO2 NPs-methane foams were achieved 20.4, 18.9, 17.6, and 16.1 %, respectively, which were 6 to 10 % higher than foam flood tests without NPs. Overall, it can be concluded that NPs methane foam flooding is a promising method for EOR from carbonate porous media in the middle east area.