Engineering the rheology and IFT behavior of mixed formulations of anionic and non-ionic surfactants with added silica nanoparticles

Abstract

Tertiary enhanced oil recovery (EOR) is one of the feasible exploitable fossils fuel to meet global energy consumption. The conventional EOR chemical approach has many disadvantages over the nano-EOR due to many unforeseen issues and loss of chemicals in the porous medium, affecting the techno-economic of the projects. The nano-EOR approach can augment and modify the rock-fluid interaction and mobility. It is a promising approach at the nanoscale to provide a unique platform to revolutionize the EOR process for ultimate oil gain. The other critical parameters, such as IFT, wettability, capillary pressure, and rheology, can also influence the rock-fluid interaction at the interface. The author has focussed mainly on the impact of IFT, surface tension, and rheology of nano silica-surfactant formulation (Alkyl benzene sulfonate-triton-x-100) in the presence of 3 wt% brine, synthetic formation water (SFW) and paraffin oil. The critical micellar concentration (CMC) value of the above composition was estimated at around 50 mg/lt. The IFT has been observed around 12.21mN/m against 3 wt% brine-surfactant composition at room temperature and 8.25mN/m at higher temperatures (∼60 °C). In the case of SFW, the IFT of 14.95mN/m at room temperature and 8.55mN/m at a higher temperature. The studies have also been conducted with nano silica-surfactant-3 wt% brine composition and found the IFT of 2.85mN/m at room temperature and 1.20mN/m at higher temperatures (∼60 °C). Whereas in the case of nano silica-surfactant-SFW formulation, it was found 4. 24mN/m at room temperature and<2.0mN/m at a higher temperature. The declining trends of IFT of the above systems will modify the rock-fluid interface properties and enhance mobility under in-situ conditions. The rheological studies also confirmed that 0.10 wt% of nano silica-surfactant with base fluid composition is an optimum and desired concentration for achieving favorable rheology and better techno-economics of nano-EOR applications.