Size of Oil Droplets Under High-Water-Cut Conditions

Abstract In this paper the oil droplet size distribution as present during conventional high-water-cut oil production is discussed. The analysis is mainly based on the results of laboratory work on, firstly, core-flow experiments and, secondly, break-up in model chokes. Downhole, the size distribution is governed by the flow of oil and water out of the reservoir sections near the wellbore. It is expected that the smallest oil droplets will be in the 10–15 μm range, while the largest droplets are, presumably, of the order of centimeters. In the tubing, breakup of the largest droplets may occur, so that, eventually, the width of the size distribution will decrease somewhat in the sense that very large droplets will no longer be present. Subsequently, due to more intense break-up phenomena in the choke, the size distribution will shift to smaller droplet sizes. Downstream of the choke, the largest droplets will be in the 100–200 μm range. More information is needed for reliable predictions on the occurrence of very small droplets downstream of the choke. It is expected, however, that many droplets of sizes smaller than 10 μm will be present downstream of the choke.