Effect of Shear and Water Cut on Phase Inversion and Droplet Size Distribution in Oil–Water Flow

Abstract

Oil–water dispersed flow occurs commonly in the petroleum industry during the production and transportation of crudes. Phase inversion occurs when the dispersed phase grows into the continuous phase and the continuous phase becomes the dispersed phase caused by changes in the composition, interfacial properties, and other factors. Production equipment, such as pumps and chokes, generates shear in oil–water mixture flow, which has a strong effect on phase inversion phenomena. The objective of this paper is to investigate the effects of shear intensity and water cut (WC) on the phase inversion region and also the droplet size distribution. A state-of-the-art closed-loop two phase (oil–water) flow facility including a multipass gear pump and a differential dielectric sensor (DDS) is used to identify the phase inversion region. Also, the facility utilizes an in-line droplet size analyzer (a high speed camera), to record real-time videos of oil–water emulsion to determine the droplet size distribution. The experimental data for phase inversion confirm that as shear intensity increases, the phase inversion occurs at relatively higher dispersed phase fractions. Also the data show that oil-in-water emulsion requires larger dispersed phase volumetric fraction for phase inversion as compared with that of water-in-oil emulsion under the same shear intensity conditions. Experiments for droplet size distribution confirm that larger droplets are obtained for the water continuous phase, and increasing the dispersed phase volume fraction leads to the creation of larger droplets.