Rheological characteristics of non-Newtonian GPTMS-SiO_2 nanofluids

摘要

GPTMS ((3-Glycidoxypropyl) trimethoxysilane)-SiO2 nanofluids have the ability to alter the wettability of a rock surface and high colloidal stability, therefore, they can be used as injection fluids to enhance oil recovery in high-salinity and high-temperature reservoirs. The purpose of this study is to prepare GPTMS-SiO2 nanofluids that are stable under extreme reservoir conditions and investigate their rheological characteristics. Nanofluids with nanoparticle concentrations of 0.1 to 3 wt% were prepared and dispersed in 10 wt% API (American Petroleum Institute) brine, which served as the base fluid. The apparent viscosity of the base fluid and GPTMS-SiO2 nanofluids was measured in the shear rate range 3.7 to 93.1 s(-1) between the temperatures of 5 and 85 degrees C. It was observed to be a function of temperature, but remained constant with the increase in shear rate. On the other hand, the nanofluids exhibited pseudoplastic behavior (shear thinning). The apparent viscosity of the nanofluids tended to increase with decreasing temperature and increasing particle concentration. The consistency index and power law index of the power law fluid model are used for the analysis of the flow behavior of the nanofluids. The consistency indices of GPTMS-SiO2 nanofluids were observed to be well matched with the exponential function, and the power law indices showed high correlations with the specific particle concentration and temperature conditions. The results revealed that the rheological characteristics of GPTMS-SiO2 nanofluids are functions of particle concentration and temperature at specific conditions.