Experimental study of emulsions in the brine-oil-enzyme systems involving solid fines

Jakub Benicek, Alsu Khusainova, Alexander Shapiro, Christos Panagiotis Chatziagapiou

Abstract

Experimental study of formation of emulsions in brine-oil-enzyme systems with solid fines was carried out. The study was directed to analysis of the possible mechanisms governing the enzymatic enhanced oil recovery (EEOR). Formation of emulsions may serve to mobilization of the separate oil droplets, resulting in additional recovery.

N-Decane was selected as model oil to investigate emulsifying ability of the different enzymes. It was found that North Sea oil with enzyme formed the same amount of emulsion when diluted by the different amounts of n-Decane; hence, n-Decane can represent behavior of the crude oil in this case. The emulsions formed in brine-n-Decane-enzyme systems were found to be stable for minimum of a month.
The long-chain alkanes were found to form more stable emulsions. For a lipase/esterase enzyme, the effect of hydrolysis of ester was tested. The results showed decrease of the amount of the formed emulsion and decrease in the droplet size distribution (DSD). Enzymes/proteins produced more emulsions compared to the surfactant, sodium dodecyl sulfate. Increase of the enzyme concentration from 1 wt. % to 5 wt. % resulted in creation of more droplets while the bulk amount of emulsion was similar.

Addition of CaCO₃ particles (≤30 μm) together with an enzyme caused intensification of the emulsion formation compared to the case when only enzyme was added. Application of SiO₂ particles (0.5-10 μm) formed an emulsion with and without the presence of an enzyme. The SiO₂ ­­particles covered the droplet interfaces, unlike CaCO₃ particles. Addition of enzymes to the particles did not decrease DSD. A negative tendency was observed with an increase of concentration of an enzyme on emulsification in presence of CaCO₃ particles.