Abstract
Gas injection in hydrocarbon reservoirs faces challenges, such as low macroscopic sweep efficiency and poor mobility control due to the low density and viscosity of injected gases, leading to gas fingering and gravity segregation. These problems can be resolved by injection of gas as foam to enhance gas mobility as well as sweep efficiency. However, during the foam injection in hydrocarbon reservoirs, foam stability is a crucial factor to enhance the recovery of the process, which could be improved by nanoparticles. Motivated by this interest, the present study aims to generate and stabilize foam with varying nanoparticle concentrations (0.02 to 0.1 wt%) in combination with a 0.236 wt% SDS surfactant, both in the presence and absence of MgCl₂, K₂SO₄, NaCl, and Na₂SO₄ salts. Techniques such as Fourier Transform Infrared (FTIR) spectroscopy, X-ray Diffraction (XRD), and Dynamic Light Scattering (DLS) confirm successful NP surface modification. The use of vinyltriethoxysilane (VTES) for nanoparticle surface modification increased foam stability. Additionally, micromodel flooding experiments were conducted, and the results were analyzed to assess the transport properties of the fracture-matrix and the oil recovery characteristics of injection materials, including carbon dioxide gas, SDS solutions, and foams stabilized by silica nanoparticles. According to the findings, silica nanoparticle surface modifications with VTES resulted in a 30% increase in the foam stability of silica nanoparticle, compared to its unmodified counterpart. In addition, the unmodified and VTES-modified silica nanoparticles enhanced foam stability in comparisons with the base case including pure SDS surfactant by 22.3% and 61.1%, respectively. Even though the salt ions (MgCl₂, K₂SO₄, NaCl, Na₂SO₄) decreased the level of foam stability on average by 40–50%, the interaction of salt ions with the modified foams also revealed important information about the EOR performance. In addition, the micromodel flooding tests indicated that the surfactant foam with VTES-modified nano-silica produced the maximum oil recovery (48.04%) which was drastically higher than that of SDS-surfactant foam alone (31.33%). SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1038/s41598-025-19355-2.