Experimental Study on the Effects of Water-in-oil Emulsions to Wall Shear Stress in the Pipeline Flow

Abstract

Study on the emulsion formation mechanically and relate the effect of emulsions to the friction or wall shear stress ( w  ) in the pipeline flow has not yet been explored. So, this study aims to understand the emulsions formation mechanically and to discover the effects of water-in-oil emulsions to the pipeline flow transport by relating the effect of emulsions to the wall shear stress or friction of the pipe. In this study, wall shear stress is compared at water cuts from 0% to 40%, Reynolds number that covers laminar (1100 < Re < 1800) and transitional (2400 < Re < 2800) flow regime, pipeline constrictions that consists of gradual and sudden contraction with a contraction ratio of 0.50 and 0.75, respectively as well as along the pipelines. To carry out the experiments, the Ultrasonic Velocity Profiler and a lab-scale flow rig were used. The results show that the maximum wall shear stress happens at 10% water cuts, higher Reynolds number results in lower wall shear stress, pipeline constriction with contraction ratio of 0.75 results in higher wall shear stress than thecontraction ratio of 0.50 and sudden constriction results in higher wall shear stress than the gradual constriction, and wall shear stress increases with the increase in the length of the pipeline downstream the pipeline constriction. In conclusion, pipeline flow with higher Reynolds number and pipeline constriction (which represents the usage of choke valve in the industries) type gradual constriction ratio 0.50 are recommended to be used in the oil and gas industries because this combination results in the lowest wall shear stress.