Enhancing oil recovery with MWCNT and GO nanocomposites in high salinity heterogeneous media

Abstract

Water injection remains the predominant method in the oil recovery process, but chemical flooding methods such as nanohybrid injection, with its distinct advantages, emerge as a promising alternative to traditional water flooding (WF). This study employed a straightforward synthesizing method, specifically the sol-gel process, to graft polyacrylamide (PAM) onto Graphene Oxide (GO) and Carbon Nanotube (CNT). The objective was to combine the advantages of both polymer and nanoparticle flooding. Our investigation comprised a comprehensive series of static and displacement tests, aiming to investigate the impact of nanohybrid injection in comparison to conventional water and polymer flooding. A series of static tests, SEM, TEM, FTIR, as well as viscosity, IFT, contact angle, and stability assessments, were conducted. As dynamic tests, a series of injection tests were done using a glass micromodel with a high degree of heterogeneity containing both connected and disconnected fractures which makes injection fluid's work very hard to recover oil. Results of static tests such as bottle and TGA, showed that the synthesized nanohybrids have great stability against harsh conditions of the reservoir in case of formation water salinity and temperature conditions which differentiates our work from previous studies. By analyzing the results of dynamic tests it was found that reduction of Interfacial Tension or IFT (which is the forces acting at the interface of nanofluids and oil) showed the most effect on oil recovery as CNT/PAM nanohybrid were able to lower the IFT value the most compared to the other injection fluids and therefore exhibited the highest oil recovery factor Alongside IFT reduction mechanism, mobility control was found to be another important factor specially in case of recovering heavy oil when GO/PAM outperformed CNT/PAM's recovery factor as GO/PAM has more viscosity than CNT/PAM.