Extracted quartz as efficient natural demulsifier for crude oil-water emulsions: Effect of monovalent/divalent salts, pH and modeling study

Smooth running of upstream and downstream operations is very key for the successful hydrocarbon production and delivery to the end users. Investigated in this study is the application of quartz particles as naturally occurring demulsifiers for demulsification activity in the petroleum industry. Effect of monovalent (NaCl and KCl) and divalent (MgSO4.7H2O, CaCO3, CaCl2 and MgCl2.6H2O) salts on the effectiveness of quartz (3 wt%) to displace the natural emulsifiers and separate water and crude oil were assessed at various temperatures (45-75 degrees C). Also, evaluated is the tolerance of quartz particles to pH change during demulsification at 75 degrees C. Modeling was applied to elucidate the measured demulsification of the produced emulsions. Experimental outcomes revealed that quartz demulsification efficiencies were slightly higher in the crude oil emulsions produced from brine containing NaCl salt as compared to the emulsions obtained from KCl salt across the various temperatures examined. Water removal by quartz particles at equilibrium for emulsions containing NaCl and KCl salts were estimated to be 98% and 95.8%, respectively, while 93% water removal was achieved in emulsions produced from either CaCl2 or MgCl2.6H2O divalent salts at 75 degrees C. However, MgSO4.7H2O and CaCO3 divalent salts impacted swift water/crude oil separation in the produced emulsions within a very short period. Quartz demulsification efficiency was great in both acidic and alkaline media; however, its performance was much more excellent in the alkaline medium, especially at pH 10. Rheological determinations and optical microscopic analysis affirmed the workability of quartz particles to distort the asphaltenes and resin layers. Sequential minimal optimization (SMO) algorithm tool in machine learning was applied to predict the experimentally determined quartz demulsification efficiencies with significant matches and correlations.