Effect of dynamic spreading and the disperse phase of crystalline starch nanoparticles in enhanced oil recovery at reservoir condition of a typical Sarawak oil field

Abstract

Nanofluid flooding has been proven to be very effective in enhanced oil recovery (EOR). The performance depends on the material and formulation process. Previous studies have focused only on the use of inorganic, metal and metal oxides nanoparticles. The use of nanofluids from natural sources has not been investigated to a reasonable extent for possible application in EOR. In this study, ascorbic acid was used for the first time to synthesize crystalline starch nanoparticles (CSNP). The physical properties of the CSNP including their size distribution and crystalline structures were investigated. The interfacial properties of the crystalline starch nanofluid (CSNF) at the interface of oil and water (O/W) were investigated at different concentrations and temperatures. The effect of the interaction between electrolyte and ultrasonic was determined. The wettability alteration efficiency of CSNF on oil-wet sandstone surface was investigated using the sessile drop method. A core flooding experiment was conducted at reservoir conditions to justify the effect of wettability alteration and dispersion of CSNF on additional oil recovery. The performance of the CSNF was compared with the conventional EOR chemical. The methods were effective in producing spherical and polygonal nanoparticles with a mean diameter of 100 nm and increased in crystallinity of 7%. The interfacial tension (IFT) decreased with increase in concentration of CSNF, electrolyte and temperature. The results show that CSNF can change the wettability of sandstone at low concentration, high salinity and elevated temperature. The pressure drops data show stability of CSNF at 120 °C. The formation of oil bank was enough to increase oil recovery by 23%. CSNF was effective in mobilizing residual oil at reservoir condition. It can, therefore, be concluded from this experiment work that the method applied herein is easier, cost-effective and can reduce energy consumption making the method economically advantageous compared to conventional methods.