Enhanced oil recovery (EOR) makes use of various chemical processes to extract additional oil from reservoirs, often already under production. In this study, authors investigated the role of the CuO@Fe 3 O 4 @xanthan nanocomposite (NCs) in EOR by the focus of the interfacial tension (IFT) and wettability alteration mechanisms. This NCs is synthesized from Artocarpus altilis extract using a simple, economical and green method. The prepared NCs is identified using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). Nanofluids are prepared from dispersing the synthesised NCs in water at different concentrations in order to be used in the density, viscosity, conductivity, IFT and contact angle measurements. The results showed an improvement in the values of IFT and contact angle. The IFT of oil/water is increased from 22 to 24 mN/m with increasing the concentration of the NCs from 250 to 2000 ppm. While, the wettability of the carbonate rock is remained water-wet, wherein the contact angle is raised from 28°to 58°with increasing the NCs concetration from 250 to 2000 ppm. Overall, the IFT and contact angle are only reduced when 250 ppm NCs was added to water from 28.3 mN/m and 132.6°mN/m to 22 and 34.5°.

The rheological properties of drilling fluids have an important role in providing a stable wellbore and eliminating the borehole problems. Several materials including polymers (xanthan gum) can be used to improve these properties. In this study, the effect of the local Katira, as a new polymer, on the rheological properties of the drilling fluids prepared as the bentonite-water-based mud has been investigated in comparison with the conventional xanthan gum. Experimental work was done to study of rheological properties of several gums such as, local katira gum, and xanthan gum bentonite drilling mud. Different samples of drilling fluids are prepared adding the xanthan gum and local katira to the base drilling fluid at different concentrations using Hamilton Beach mixer. The prepared samples are passed through rheological property tests including the apparent viscosity, plastic viscosity, and yield point (YP) under different temperature conditions. The obtained results show that the viscosity is increased from 5 to 8.5 cp and YP is increased from 18.5 to 30.5 lb/100 ft2, with increasing the concentration of the xanthan gum from 0.1 to 0.4. However, the effect of the local katira in increasing the viscosity and YP is lower compared with the xanthan gum, which are ranged between 5–6 cp and 18.5–20.5 cp.