Experimental study of wax deposition in pipeline – effect of inhibitor and spiral flow

Abstract

Wax deposition is one of the main flow assurance problems in the oil industry. It can result in the restriction of crude oil flow in the pipeline, creating pressure abnormalities and causing an artificial blockage leading to a reduction or interruption in the production. Wax can precipitate as a solid phase on the pipe wall when its temperature (inlet coolant temperature) drops below the Wax Appearance Temperature (WAT). An experimental flow loop system was built in the lab to study the variation of wax deposition thickness under the single phase transport. A series of experiments were carried out at different flow rates (2.7 and 4.8 L/min) to study wax deposition and measure the wax thickness using four different techniques including direct technique pigging, pressure drop, heat transfer and liquid displacement-level detection (LD-LD). The effect of factors on wax formation such as inlet coolant temperature, inhibitor and spiral flow has been examined. The results show the wax inhibition percentage (WI)% was 40% and 45% at flow rate 2.7 and 4.8 L/min respectively of the inhibitor W802 (polyacrylate polymer (C16-C22)) at inlet coolant temperature 14 oC. The wax reduction percentage (WR) % was 65% and 73% at flow rate 2.7 and 4.8 L/min respectively of the spiral flow at inlet coolant temperature 14 oC. This percentage of inhibition will increased rapidly by increasing the inlet coolant temperature.