No abstract

Dilute Surfactant flooding is one of the significant processes in chemical flooding. Many oil reservoirs became appropriate candidates for surfactant/water flooding when screening criteria developed. Injected surfactant tries to mobilize the residual oil that was trapped in interstice. The main contributing mechanism for oil recovery improvement by surfactant flooding is rock wettability alteration. Wettability is a one of the proper index in choosing the best approach for a successful surfactant flooding which tiny change in wettability alteration will lead to improve oil recovery. This experimental study investigated the effect of different aging time and temperature on wettability alteration with exact soaking time to find the optimum condition. Afterwards, coreflooding experiments were performed to determine the impact of dilute cationic surfactant slug with huff ‘n’ puff(cyclic 7 days) method on displacement sweep efficiency in the carbonate core from one of the Iranian oil field. Besides, contact angle and interfacial tension (IFT) measurements were done to provide the supplementary data for a surfactant/waterflooding. The optimum concentrations of C19tab, were determined by measuring interfacial tension values of the crude oil in contact with surfactant solutions, which were prepared from synthetic saline water. The results obtained from laboratory showed a reduction in residual oil saturation by changing contact angle and IFT reduction between oil and water. Aging is known as important parameter for researcher to alter the wettability. Furthermore it proves effect of wettability alteration is more than IFT reduction.

In this study, the dynamic IFT and dilational rheological behavior of fluids/nanofluids generated from cetyltrimethylammonium bromide (CTAB)-grafted faujasite (FAU)-based nanoparticles were investigated in toluene–fluid/nanofluid interfaces under various conditions. To generate each nanofluid, FAU nanoparticles were initially synthesized under ambient conditions and then grafted with various quantities of CTAB surfactants. Afterward, the surface properties (i.e., morphology, surface area, functionality, and stability) of the synthesized nanoparticles before and after grafting with a low concentration of CTAB molecules were investigated by an array of characterization methods (XRD, HRTEM, BET surface area, ζ-potential, and DLS). The results showed that our generated FAU-based nanofluids outperformed the nongrafted FAU and physically mixed CTAB with FAU-based nanofluids in terms of IFT reduction. Our experimental IFT data were fitted with a general diffusion model that allowed us to determine the oil–water (o/w) emulsification mechanism due to the presence of CTAB-grafted nanoparticles. Based on our investigation, we emphasized that the IFT reduction was limited with the loading of a substantial amount of surfactant molecules, indicating that bulky nanoparticles are adsorbed slowly on the o/w interface. On the other hand, increasing the salinity level by introducing an additional amount of NaCl led to enhancing the levels of IFT reduction since the dissociated ions forced more surfactant molecules to migrate toward the o/w interface. A considerable viscoelasticity enhancement was remarked in the presence of our CTAB-grafted nanofluids, indicating that the presence of FAU nanoparticles in the core of the grafted nanoparticles robustly allowed the adsorption of higher amounts of CTAB molecules at the interface with less aggregation. The findings of this study shed light on the applications of nanofluids generated from grafted nanoparticles at the o/w systems, which can significantly increase the oil production at the end of water flooding with more efficient emulsification with surfactant concentration lower than the critical micelle concentration (CMC).

No abstract

No abstract