LABORATORY INVESTIGATION OF NANO-POLYMER FLOODING IN CARBONATE RESERVOIRS

Abstract

The traditional chemical Enhanced Oil Recovery (EOR) method like polymer flooding is widely used in the petroleum industry. However, a new method of chemical EOR has been paid much attention in the field of research. It comprises a combination of silica nanoparticles with polymer. Researchers have conducted various experiments on silica nanoparticles/polymers flooding. The focus of this study is to investigate the silica nanoparticle's behavior dissolved in hydrolyzed polyacrylamide (HPAM) by coreflooding experiments and calculate the oil recovery. It is known that polymer solution has a high viscosity, decreases the mobility ratio, thus, affects to the macroscopic sweep efficiency, which increases the oil recovery. At the same time, it was investigated that nanoparticles have the capability of wettability alteration, decreasing the interfacial tension (IFT) and protection from polymer degradation, therefore, increasing the microscopic sweep efficiency. The optimum concentrations for hydrolyzed polyacrylamide (2000 ppm) and silica nanoparticles (0.1 wt %) were selected via rheology experiments and contact angle measurements. Zeta-potential tests showed an addition of salt decreases the stability of nano-silica/polymer solutions. The result of the contact angle measurements revealed that silica nanoparticles alter the wettability of surfaces. For 0.1 wt % nanoparticle solution, there is a maximum deviation of 45.6° in contact angle. Rheology experiments indicate that the addition of silica nanoparticles to polymer solution increases the viscosity, so the nano-silica/polymer has a higher viscosity than the polymer solution itself. A series of core flooding experiments are provided using brine, hydrocarbon, polymer, silica nanoparticles, and salt. The maximum oil recovery of 87.045 % was determined from the second scenario, injecting silica nanofluid followed by nano-assisted polymer solution as an EOR technique. It is a unique study since different flooding sequences are applied combining silica nanoparticles and modified synthetic polymer. Therefore, the use of silica nanofluid followed by nano-assisted polymer solutions as an EOR technique demonstrated a great impact on oil recovery mechanisms. In porous media, silica nanoparticles enhance the performance of polymer solutions. Such research will open new avenues for hybrid EOR applications.