Many of the oil fields are found in carbonate reservoirs which are preferentially oil-wet, therefore, the oil recovery from these reservoirs by waterflooding techniques is relatively low[1]. In order to increase oil recovery from oil-wet carbonate reservoirs, wettability alteration is an important method. Recently, many chemical agents like surfactants known as wettability modifiers have been widely applied in oil recovery process. Moreover, many researchers have suggested that by the addition of nanoparticles, the mobility and effectiveness of wettability modifiers can be increased[2]. In this study, the effect of SiO2-based nanofluids on the wettability alteration of a carbonate reservoir rock was systematically investigated[3]. The wettability alteration was shown by contact angle. With the characteristics of nanoscale particle size and surface energies, SiO2 nanoparticles (particle size 15nm) could easily adsorb on carbonate surfaces to change the wettability of the system, and reduced the contact angle from 140 ± 3° to 30 ± 3° with the concentration of 0.05wt%. Scanning electron microscope (SEM) images revealed that nanoparticles took on a form of aggregation with the average size (20～40nm) which was larger than their primary particle size (15nm). Based on our research results, nanoparticles had a high tendency to form nanotextured layer on surfaces in combination with surfactants, which could affect the wettability of carbonate rocks more strongly.

Preliminary study on wettability alternation of surface of carbonate rocks using SiO2 nanofluids

253rd National Meeting (2017)

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