Application of natural polymers and nanoparticles in enhancing oil recovery at reservoir condition

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 which have limited full-scale field application due to cost and environmental concerns. The use of nanofluid from natural sources has not been investigated to a reasonable extent for possible application in EOR. In this research, three natural polymers were formulated from local materials from Malaysia and Nigeria. Ascorbic acid was used to synthesize the natural polymers to nanoparticles. The physical properties of the nanoparticles including their size distribution, crystalline structures were investigated. The rheological properties of the nanofluids were compared with natural polymers and commercial polymer xanthan. The interfacial properties of the nanofluids at the interface of oil and water were investigated at different concentrations and temperatures. The effect of interaction between electrolyte and ultrasonic was determined. The wettability alteration efficiency of the nanofluids on oil-wet sandstone surface was investigated using the sessile drop method. Core flooding experiment was conducted at high temperature high pressure (HTHP) reservoir conditions to justify the effect of wettability alteration and dispersion of the nanofluids on additional oil recovery. The performance of the nanofluids were compared with 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 viscosity increased with increase in surface area and temperature of the crystalline starch nanofluid (CSNF), Cissus populnea nanofluid (CPNF), Cissus populnea (CP) and cassava starch (CS) compared to a decrease in viscosity as the temperature increases for okra, okra lignocellulose nanofluid (OLCNF) and xanthan. The interfacial tension decreased with increase in concentration of the nanofluids, electrolyte and temperature. The results show that the nanofluids can change the wettability of sandstone at low concentration, high salinity and elevated temperature. Oil recovery after waterflooding was 48% of original oil in place (OOIP), the oil recovery of okra, CS and CP increased by 13%, 15% and 17% respectively, compared to 11% OOIP obtained with xanthan. The pressure drop data shows stability of OLCNF, CPNF and CSNF at 120 ºC and the formation of oil bank was enough to increase the oil recovery by 20%, 23% and 26% respectivelNanofluid 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 which have limited full-scale field application due to cost and environmental concerns. The use of nanofluid from natural sources has not been investigated to a reasonable extent for possible application in EOR. In this research, three natural polymers were formulated from local materials from Malaysia and Nigeria. Ascorbic acid was used to synthesize the natural polymers to nanoparticles. The physical properties of the nanoparticles including their size distribution, crystalline structures were investigated. The rheological properties of the nanofluids were compared with natural polymers and commercial polymer xanthan. The interfacial properties of the nanofluids at the interface of oil and water were investigated at different concentrations and temperatures. The effect of interaction between electrolyte and ultrasonic was determined. The wettability alteration efficiency of the nanofluids on oil-wet sandstone surface was investigated using the sessile drop method. Core flooding experiment was conducted at high temperature high pressure (HTHP) reservoir conditions to justify the effect of wettability alteration and dispersion of the nanofluids on additional oil recovery. The performance of the nanofluids were compared with 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 viscosity increased with increase in surface area and temperature of the crystalline starch nanofluid (CSNF), Cissus populnea nanofluid (CPNF), Cissus populnea (CP) and cassava starch (CS) compared to a decrease in viscosity as the temperature increases for okra, okra lignocellulose nanofluid (OLCNF) and xanthan. The interfacial tension decreased with increase in concentration of the nanofluids, electrolyte and temperature. The results show that the nanofluids can change the wettability of sandstone at low concentration, high salinity and elevated temperature. Oil recovery after waterflooding was 48% of original oil in place (OOIP), the oil recovery of okra, CS and CP increased by 13%, 15% and 17% respectively, compared to 11% OOIP obtained with xanthan. The pressure drop data shows stability of OLCNF, CPNF and CSNF at 120 ºC and the formation of oil bank was enough to increase the oil recovery by 20%, 23% and 26% respectively. The nanofluids were found to be very effective in mobilizing residual oil at HTHP reservoir condition.