Evaluation of Aluminium Oxide and Titanium Dioxide Nanoparticles for EOR Applications

Abstract

Utilization of nanoparticles in EOR have gained high attention recently, with good but controversial results reported on improving oil recovery. Within this work two types of nanoparticles are selected and assessed, to determine its effect in oil mobilization. The experimental evaluation is performed using micromodels (EOR chips), in combination with a detailed nanofluids characterization. The workflow presented is a useful approach that can extended among different laboratories as preliminary evaluation. The workflow comprises a set of interrelated steps: 1) Selection and preparation of the Aluminium Oxide (Al2O3) and Titanium Dioxide (TiO2) nanofluids, influenced by recent literature comparisons, 2) Detailed rheological evaluation of nanofluids and oil, 3) Investigation of the Fluid-Fluid interaction by means of the interfacial tension (IFT) and nanoparticles effects in oil viscosity, 4) Two-phase flow experiments using EOR chips (breakthrough and mobilized oil vs PV injected), 5) Image processing analysis, leading to 6) Quantitative and qualitative analysis of the experimental data. As expected, we observed that diluting nanoparticles in fresh water increased the stability compared to brine. It was required the use of a stabilizer to optimize nanofluids characteristics. Unlike reported in the literature where Polyvinylpyrrolidone (PVP) is used, we found that adding Poly(ethylene oxide)-(PEO) leads to a more stable nanofluids. There, seemed to be a tendency for the Al2O3 nanoparticles to reduce the viscosity of the aqueous-phase, when combined with PEO. Moreover, when Al2O3 was added to the oleic-phase increased its viscosity, with a strong dependency of soaking process. The image process analysis allowed to generate algorithms to calculate concentrations and saturations among the two-phase flow experiments. These algorithms proved to be highly beneficial enabling qualitative and also quantitative analysis of mobilized oil zones, as well as plugged areas. The experimental results did not show a significantly strong increase in mobilized oil due to Titanium Dioxide nanofluids, but slightly better results were observed with the Alumnium Oxide nanofluid in a low concentration. Much research in recent years has focused on the study of Silica nanoparticles. Since different other nanoparticles can be commercially found, this work presents additive information to the existing body of literature. Moreover, the workflow presented can be used by fellow researchers as preliminary tool for laboratory evaluations. These, to obtain potential useful insights from oil mobilization by the application of nanoparticles flooding.