This study, aims to investigate the effect of nanoparticles/polymer on CO2-foam stability and foamability of Alpha Olefin Sulfonate, AOS at high temperature and salinity conditions. Moreover, the effect of extra hydrocarbon phase on foam stability at high temperature and salinity conditions is studied. Static CO2-foam experiments were conducted according to ASTM: D3601 standard method for bulk foam stability in aqueous media, to analyse the foam half-life and its real time stability with nanoparticles and polymer at high temperature and salinity conditions in the presence of hydrocarbons. The average bubbles size distribution and foam texture were analysed using an Olympus stereo microscope SZX100 equipped with 5 mp camera.
The results show that the CO2-foam stability enhanced with increasing nanoparticles/polymer concentrations up to threshold values. The optimum concentrations to achieve the maximum stability were 0.2 wt% and 0.3 wt% for silica and xanthan gum, respectively.
In order to understand the performance of the optimum foam composition in presence of extra hydrocarbon phase at reservoir condition, foam then brought into contact with a North Sea oil sample. The results shown that the foam stability was not changed when oil saturation increase up to 3.0 vol%, but was completely deteriorated when the concentration reaches 40.0 vol%.
This study suggests that optimum concentrations of nanoparticles and polymer at a high temperature and salinity conditions should be determined before the design of any foam-based enhanced oil recovery process.