Study on SiO2 Nanofluid Alternating CO2 Enhanced Oil Recovery in Low-Permeability Sandstone Reservoirs

Water alternating gas (WAG) flooding is a widely employed enhanced oil recovery method in various reservoirs worldwide. In this research, we will employ SiO2 nanofluid with the CO2 injection as replacement for conventional WAG process experiments. The suffers from limitations certain industrial applications, such extended cycle times, susceptibility to water condensation and agglomeration, ineffectiveness low-permeability reservoirs, thus impeding factor. order solve these problems, study introduces substitute medium proposes alternate enhance recovery. Through microcharacterization of nanofluids, comprehensive evaluations particle size, dispersibility, emulsification performance were conducted. experimental results revealed that both SiO2-I SiO2-II nanoparticles exhibited uniform spherical morphology, sizes measuring 10–20 nm 50–60 nm, respectively. formulations demonstrated excellent stability properties, highlighting their potential utility petroleum-related applications. Compared other methods, effect better, smaller best. Nanofluids exhibit wetting modification effects on sandstone surfaces, transforming surface wettability oil-wet water-wet. This alteration reduces adhesion forces enhances mobility, thereby facilitating improved fluid flow rock matrix. experiments different slug sizes, can delay breakthrough time nanofluids CO2, enhancing effectiveness EOR. Among them, size 0.1 PV approaches optimal performance, further reducing has limited impact improving development efficiency. ratios, ratio found be 1:1. Additionally, using cores varying permeability, lower permeability demonstrate higher rates.