Comparative effectiveness of production performance of Pickering emulsion stabilized by nanoparticle-surfactant-polymerover surfactant-polymer (SP) flooding for enhanced oil recoveryfor Brownfield reservoir

Nanotechnology offers potential benefits for improving the next-generation enhanced oil recovery (EOR) process from Brownfield reservoirs. In our recent study (Sharma et al., 2014a), we formulated novel Pickering emulsion stabilized using conventional oilfield polymer polyacrylamide (PAM) and nanoparticles (SiO2 and clay) in the presence of surfactant, which is thermally stable at elevated temperature and suitable for EOR application. In this study, the use of these Pickering emulsion is investigated for enhanced oil recovery. Two types of flood systems, viz., surfactant-polymer (SP) and o/w Pickering emulsion flood, are prepared and used for 12 core flooding experiments to study the additional oil recovery at reservoir pressure of 13.6 MPa and temperature ranges from 313 to 363 K. These reservoir conditions of pressure and temperature are representative to one of the mature reservoirs in India. The incorporation of nanoparticle was observed to provide relatively lower and stable interfacial tension (IFT) for the Pickering emulsion. The viscosity of SP system was observed to decrease with temperature (313-363 K), while that of Pickering emulsion was observed to remain stable and thereby indicating a possible stable mobility ratio downhole during EOR. Nanoparticle stabilized Pickering emulsion observed to give enhanced oil recovery by about 80% more at elevated temperatures as compared to conventional SP flood, showing promising advantages of employment of nanoparticles in oilfield industry. The investigation on the permeability reduction indicated a relatively larger retention of SiO2 nanoparticle than its counterpart clay, which is attributed to its larger size in the system.