Optimum volume fraction of nanoparticles for enhancing oil recovery by nanosilica/supercritical CO2 flooding in porous medium

摘要

Immiscible gas injection is a practical process in enhanced oil recovery (EOR) methods, but the important defects of this injection type are recognized as the creation of finger and quick breakthrough of the injected fluid in terms of the gas low viscosity and also inappropriate mobility ratio. Along with the nanotechnology advancement, special attention has been paid to the nanoparticles usage. It is possible that nanoparticles addition could enhance the gas viscosity and the injected gas density, and the result is increasing the oil recovery factor from reservoirs. Therefore, the purpose of this study was to investigate the nanoparticles presence in injected supercritical gas effect on the oil recovery. Therefore, here mathematical equations were modeled that were relevant to nanosilica/supercritical CO2 injection into a long fully oil saturated core, and they were solved using MATLAB software. Results indicated that for the light oil by nanoparticles addition up to 3.5 vol %, oil recovery would increase with a constant slope, but for the amounts higher than 3.5 vol % of the nanoparticles, oil recovery increment slope tends to zero, and after 4 vol % of the nanoparticle oil recovery factor indicates reduction. The maximum ultimate light oil recovery factor achieved by supercritical CO2 injection in the 4 vol % presence is 30.47%. Although, for heavy oil by nanoparticles addition in the range of 0-5 vol %, oil recovery will be gradually increased. Consequently, the maximum ultimate heavy oil recovery factor obtained by supercritical CO2 injection is 27.82% in 5 vol % presence.