Spectroscopic analysis of the adsorption of carbon based nanoparticles on reservoir sandstones
Noorhana Yahya, Abdullah Ali Halage, Fatai Adisa Wahaab, Surajudeen Sikiru
Abstract
The development of effective recovery techniques that can resolve the complexities of high interfacial tension (IFT), high viscosity and wettability in petroleum reservoirs will aid efforts to meet the world’s growing energy demands. Nanoparticles prove to be able to form adsorption layers on surfaces of sandstone and significantly change wettability and IFT. Despite the remarkable properties of graphene nanopaticles, not many studies have researched their potential application in EOR. In this study, sandstone coreplugs infused with crude oil, brine and carbon nanofluids (carbon nanocomposite and graphene) were characterized using field emission scanning electron microscopy (FESEM), Fourier Transform Infrared (FTIR), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). IFT measurements were performed for oil/brine/CNPs and graphene nanofluid. The measured IFT values for brine/oil, carbon nanofluid/oil and graphene nanofluid/oil are 39–40 mN/m, 41–44 mN/m, and 9.8–11.4 mN/m, respectively. Spectroscopic analyses show that graphene has a stronger interaction (higher adsorption) on sandstone compared to the normal carbon nanoparticles, which is indicated by the lower Si–O Raman, lower FTIR transmittance for C–H peaks and the emergence of loss feature phenomenon in the XPS spectra of graphene infused with sandstone. The relatively lower FTIR transmittance intensities, well distributed carbon atoms and detected D' and D+D' Raman shifts also support the high interaction of graphene with oil and rock surface. The higher IFT reduction by graphene nanofluids is attributed to the combined high hydrophobicity and hydrophilic natures, which provides a dynamism for their detachment at the biphasic liquid/fluid interface.