| Summary: | Alkaline-surfactant-polymer (ASP) flooding is a promising chemical enhanced oil recovery (EOR) method due to its synergy, but ASP interaction with reservoir mineral tend to promote surfactant loss through adsorption, which could degrade efficiency of the process. Streaming potential has been widely studied to monitor water flooding due to its real-time data acquisition and environmental- friendly approach, however, addition of ASP solution leads to its uncertain behaviour. Therefore, this research aims to analyze adsorption of ionic surfactant and its effect on streaming potential behaviour in ASP formulation at varying brine and alkaline concentrations and to correlate the streaming potential with surfactant adsorption and oil recovery. The reservoir minerals (kaolinite and quartz) were characterized using Brunauer-Emmett-Teller, scanning electron microscopy with energy dispersive X-ray spectroscopy and Fourier transform infrared spectroscopy, while critical micelle concentrations (CMCs) of ionic surfactants in ASP formulation were analyzed at varying brine and alkaline concentrations. Anionic sodium dodecyl sulphate (SDS) and cationic cetyltrimethylammonium bromide (CTAB) were formulated as ASP with sodium carbonate (alkaline) and partially hydrolyzed polyacrylamide (HPAM) polymer. HPAM concentration was fixed at 500 ppm, while sodium carbonate and sodium chloride brine were investigated at concentrations ranging from 10000 to 30000 ppm. Static adsorption tests were conducted at a 1:5 mass-to-volume ratio of mineral to solution, where UV-visible spectrometer was used to measure the adsorption rate. The sand pack model with an approximate porosity and permeability of 0.398 and 1.925D was integrated with streaming potential data acquisition system set-up for measurements of adsorption, oil recovery and streaming potential. The characterization results revealed that kaolinite (7.13 m2/g) with a larger accessible surface area than quartz (1.39 m2/g), can promote higher surfactant adsorption, while proving the occurrence of surfactant adsorption with presence of overlapping stretching bonds after treatment. The CMCs of SDS and CTAB were found at 2200 ppm and 370 ppm, respectively, and reduced with increasing brine concentration. In ASP formulation, increasing brine concentration from 10000 to 30000 ppm has increased adsorptions of SDS (31.4%) and CTAB (29.3%). As alkaline concentration increased from 10000 to 30000 ppm, a reduction of SDS adsorption (43.8%) and increment of CTAB adsorption (46.2%) were observed. Langmuir, Freundlich, Temkin, and Linear expressions were found well-fitted to both SDS and CTAB surfactant adsorption data in ASP formulation. From the correlation, the highest oil recovery of 70.0% original oil in place (OOIP) was achieved by SDS at 10000 ppm brine with adsorption rate of 1.55 mg/g and streaming potential of 8.71 mV, while 30000 ppm alkaline has increased the oil recovery (75.3% OOIP) with adsorption rate of 1.24 mg/g and streaming potential of 8.32 mV. Meanwhile, CTAB obtained the highest oil recovery (68.4% OOIP) at both 10000 ppm brine and alkaline concentrations, with adsorption rate of 1.43 mg/g and streaming potential of 8.83 mV. Therefore, this research has revealed a significant correlation between streaming potential, surfactant adsorption and oil recovery in ASP flooding at varying brine and alkaline concentrations, which could be a potential and new approach in monitoring the efficiency and thus improving the chemical EOR processes.
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