This presentation reports the effect of wettability on bubble nucleation in a gas saturated oil-water system. The wettability and roughness of the substrates were quantified using a goniometer and an atomic force microscope (AFM). The two liquid components used in this study were water and n-decane. Two ultra-high purity gases, <i>viz.</i> carbon dioxide (highly soluble in water) and methane (sparingly soluble in water) were used separately to conduct the bubble nucleation experiments. Equal heights of water and n-decane were taken in a glass vial of known wettability and saturated at 6000 mbar pressure in a pressure cell at room temperature using either of the gases. To initiate the gas liberation process, 500 or 100 mbar of step-down pressures were applied to the pressure cell.<br/>The average onset pressures for carbon dioxide and methane gas bubble nucleation on hydrophobic vials with 500 mbar step-down pressure were 4333±289 and 3833±289 mbar, respectively. It should be noted that bubble nucleation was observed only on the solid surface portion that was in touch with the water medium for all experiments. Bubble nucleation was not observed with 100 mbar step-down pressure for either of the gases on hydrophobic vials. Bubble nucleation was not observed in the hydrophilic vials even when the pressure was reduced to atmospheric pressure with either of the step-down pressures and gases. Bubble nucleation was not observed in hydrophilic vials even when the step-down pressure was increased to 6000 mbar.

Effect of wettability on pressure-driven bubble nucleation in oil-water system

ACS Spring Meeting 2021

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