Environmentally Friendly Nanocomposite Functionality of Improved Oil Recovery (IOR) in Unconventional Reservoirs

The depletion of conventional gas and oil reservoirs has a tendency to explore unconventional resources. By leveraging cutting-edge techniques and materials, petroleum engineers can unlock new energy sources while minimizing the environmental impact. This research used an environmentally friendly nanocomposite known as CeO2@nanoclay to investigate improving oil recovery in shale reservoirs by altering wettability. Additionally, ion engineering was assessed with and without incorporation of NCs (nanocomposites). For this purpose, a comprehensive investigation was conducted on the effects of various salinity levels and nanocomposite concentrations (ranging from 100 to 1200 ppm) on wettability alteration, rock surface roughness, and Young's modulus. Utilizing the environmentally friendly CeO2@nanoclay nanocomposite with ion engineering represents an innovative strategy for enhancing reactions at the rock-fluid interface and improving wettability alteration performance. Furthermore, AFM and nanoindentation analyses were employed to investigate the impact of fluid on the roughness and hardness of rock surfaces and their correlation with contact angle measurements. The results showed that in the optimal concentration of the nanocomposite (700 ppm), where the contact angle in shale was reduced from 135.64 (2 h soaking) and 136.35 (48 h soaking) degrees (for a system of rock-oil phase-deionized water) to the minimum point 55.91 (2 h soaking) and 41.96 (48 h soaking) degrees for CeO2@nanoclay, and in the case of the hybrid state (300 ppm) from 87.29 (2 h soaking) and 59.6 (48 h soaking) degrees (for a system of rock-oil phase-50 000 ppm NaCl) to 60.16 (2 h soaking) and 52.73 (48 h soaking) degrees for the hybrid state of CeO2@nanoclay and NaCl; so, in the hybrid state, this decrease in contact angle was not seen more in the optimum concentration. During AFM and nanoindentation tests, it was found that the nanocomposite and NaCl increased the surface roughness in all cases, especially in 700 ppm CeO2@nanoclay by 82.7%, also by comparing Young's modulus of dry rock samples with saturated samples, it was found that in all cases, rock saturation caused a decrease in Young's modulus. The most significant reduction in Young's modulus was observed in the rock saturation state with the CeO2@nanoclay+NaCl solution by 64.1%. With a comparison between roughness and contact angle, roughness can be one of the influential factors in improving wettability. Therefore, this study suggests using the nanocomposite in unconventional shale reservoirs to enhance the wettability of hydraulic fracturing and EOR (enhanced oil recovery) processes.