Among several proposed enhanced oil recovery (EOR) methods, smart water injection is one of the most widely examined methods due to its unique advantages on wettability alteration. Besides, another well-known EOR method is surfactant flooding, which has a strong capability of altering both the IFT and the rock wettability. Thus, the current study is concentrated on the application of these two methods combined using Design Expert (DE) and Response Surface Methodology (RSM) approaches to make the measurements more systematic. Furthermore, for the purpose of this study, a cationic surfactant, namely, C₁₂TAB and salts such as NaCl, Na₂SO₄, MgCl_2, and CaCl₂ are utilized. Contact angle measurements using constant concentrations of ions and C₁₂TAB are performed to find the best operating conditions followed by the core flooding experiment. In summary, the obtained results revealed that the combination of ions and C₁₂TAB is capable of changing the contact angle from 90° to 14 ^o while surfactant solution without divalent ions alters the wettability from 90° to 71°. Moreover, the results demonstrated that a combination of C₁₂TAB and monovalent ions is less effective than a combination of C₁₂TAB and divalent ions. Finally, the core flooding results illustrated that it is possible to achieve the ultimate oil recovery of about 43.7% to 90.66% based on original oil in place (OOIP).

Due to the geographical location and technological limitation, various novel enhanced oil recovery (EOR) methods has been proposed to recover the remaining oil from a depleted oil reservoir. Research on application of nanoparticles either on its own or coupled with other stimulating agents has been growing enormously and some of them have shown a promising future. In high temperature and high pressure reservoirs, thermal degradation will cause failure to the conventional chemicals. In this work, temperature-stable YIG magnetic nanoparticles with an electromagnetic wave has been proposed as a new candidate for reservoir stimulating agent. The purpose of nanoparticle injection is to increase the sweep efficiency in the reservoir by increasing the viscosity of displacing fluid. In this research, Yttrium iron garnet (YIG) nanoparticles have been injected into a waterflooded oil saturated porous medium to recover the remaining oil in the presence of an electromagnetic wave. At the sintering temperature 1200°C, a mixture of hematite and YIG was obtained, suggesting a higher temperature for single phase YIG. From VSM analysis, the average magnetic saturation, coercivity and remanence are 18.17 emu/g, 21.73 Oe and 2.38 emu/g, respectively. 1.0 wt% of YIG nanofluid was prepared and subsequently injected into the pre-saturated porous medium in the presence of square electromagnetic wave of 13.6 MHz. As much as 43.64% of the remaining oil in place (ROIP) was recovered following the injection of 2 pore volume of YIG nanofluid.

Presence of GO in PU muffles discharge of heat, smoke and CO and CO2 into atmosphere. The maximum improvement in mechanical properties achieved by including 2.0 wt-% of GO in PU framework, indicating an increase in tensile stress and elongation at break of 155.1% and 27.7% compared to PU. Primary temperature of thermal degradation of PU/GO nanocomposite increased by 36.5°C with 3.0 wt-% of GO. Charred yield of PU/GO composites augmented due to GOs’ physical hindrance which limits diffusion of flammable gas. Muffling effect of GO in danger of flame and smoke exposure of polymer composites decreased by introduction of 3.0 wt-% of GO. Uniform distribution of GOs within PU matrix formed a strong, twisted route and sticky char in PU/GO composites and delayed thermal deterioration process. Thereby, this work introduces an important method for improving thermal stability and fire protection of PU providing an effective application for coating industry.