Potential Application of Fe_2O_3 and Functionalized SiO_2 Nanoparticles for Inhibiting Asphaltene Precipitation in Live Oil at Reservoir Conditions

摘要

Despite the numerous works devoted to the effect of nanoparticles on asphaltene formation, their potentials for controlling asphaltene precipitation in live oils at realistic pressure–temperature conditions of oil fields have not been studied. In this study, Fe_(2)O_(3) and functionalized SiO_(2) nanoparticles were synthesized to investigate theirs effects on asphaltene precipitation and aggregation in a light live oil with a high asphaltene deposition risk. The high pressure-high temperature (HPHT) experiments including solid detection system, high pressure microscopy and HPHT filtration were designed and conducted. The results show that during depressurization of the oil at 274.9 °F, treating the live oil with 150 ppm of F-SiO_(2) nanoparticles leads to over 600 psi delay of asphaltene onset pressure; however, in the presence of the same amount of Fe_(2)O_(3) nanoparticles, the oil remains more stable and no asphaltenes precipitation is detected. Therefore, compared to the F-SiO_(2), the Fe_(2)O_(3) nanoparticles better control the asphaltene precipitation and aggregation. This may arise from the higher number and stronger interactions of the acidic/basic functional groups of the asphaltenes with the surface sites of the Fe_(2)O_(3) nanoparticles. TEM images show that the size of irregular tangled asphaltene structures is decreased from 110 to 150 nm to 40–80 nm due to the addition of the nanoparticles to the live oil. Furthermore, the average interlayer spacing of the aromatic sheets of the asphaltene in aggregates is increased from 0.385 nm in blank live oil to 0.470 and 0.442 nm in the live oil treated with Fe_(2)O_(3) and F-SiO_(2), respectively. The consistency of different experimental results in this work provides invaluable insight for oil field applications of nanoparticles as a practical method to control the damages induced by asphaltene precipitation.