Experimental investigation of wettability alteration in sandstone rock by nanoparticles, gelatin biopolymer, salt ions, and synthesized FeO/gelatin nanocomposite for EOR applications.

Wettability is crucial to enhanced oil recovery (EOR) techniques and reservoir efficiency because it improves the EOR process's performance. The objective of this research is to investigate the impact of synthesized FeO/gelatin nanocomposite (Fe/G NC) and compare it with nanoparticles (NPs), salt ions, and gelatin biopolymer on the wettability change of sandstone (quartz) rock. Furthermore, the impact of sodium dodecyl sulfate (SDS) surfactant, the advantages of mixing iron oxide (FeO) NPs with the SDS, and aging time were investigated. First, the pure quartz contact angle was 50°. Then the contact angle measured for the quartz after aging (22 days) with crude oil was 107°. The adsorption of polar and heavy elements in oil leads to an increase in the contact angle. The contact angle of the quartz after 11 days of aging in silica (SiO), FeO nanofluids, and SDS surfactant decreased from 107° to 51.38°, 46.21°, and 41.67°, respectively. SDS, via a hydrophobic reaction with the oil phase, leads to the quartz becoming water-wet. The wettability reformation mechanism by NPs is disjoining pressure. Afterward, the contact angle of aged quartz in gelatin and Fe/G NC decreased from 107° to 33.9° and 25.13°, respectively. Since gelatin contains both hydrophilic and hydrophobic amino acids, it can function as a biosurfactant. The creation of new interactions with polymer chains by NPs in synthesized nanocomposite led to a substantial reduction of the contact angle. Increasing the aging time causes more decreases in the contact angle. Also, the synergistic effect of combining FeO NPs with SDS led to a considerable reduction in the contact angle. Thus, FeO/SDS solution treatment reduced the quartz contact angle to 32.64°, indicating water-wet conditions.