Evaluation of stability for flowing water-in-oil emulsion in transportation pipeline

Abstract

Water-in-oil (w/o) emulsion transportation technology will be applied to an old crude oil pipeline, trying to solve the operating problems caused by excessively low flow rate. To avoid intensifying internal corrosion, it needs to guarantee the full emulsification of oil and water during the whole transportation process. An experimental evaluation method of stability for flowing w/o emulsion was put forward based on the operating conditions of the oil pipeline. Firstly, w/o emulsion samples were prepared in laboratory by inverse technique to reproduce the field emulsions. Furthermore, the experimental evaluation of emulsion stability was conducted in a stirring vessel system. The experimental conditions were designed according to the thermal and shear process experienced by the oil-water mixture. The changes of emulsified water fraction were measured to evaluate the emulsion stability in different transportation processes. The results indicated that the emulsion stability was better under low transportation temperature, small water fraction and low soil temperature. A field test was conducted and the field data were able to verify the reliability of the experimental evaluation method. This research can be used to investigate the feasibility of w/o emulsion transportation technology and help to formulate reasonable transportation strategy. It can also be promoted to other oil-water transportation pipelines to judge the oil-water emulsification states.