Investigation of Inhibitors Efficacy in Wax Deposition Mitigation Using a Laboratory Scale Flow Loop

The deposition of wax in the inner walls of subsea crude oil pipelines is severe operational issue in the production and transportation of oil.  Chemical inhibition technique is one of the promising method to mitigate the risk associated with wax deposition in the pipelines.  The efficiency of different polymer based chemical inhibitors (PI-A and PI-B) on wax deposition at laminar and turbulent conditions is investigated using a laboratory scale flow loop using Shah Deniz (SD) condensate.  The thickness calculated by the deposit mass collected is consistent with that obtained by pressure drop method.  For the laminar flow, the deposit thickness has significantly decreased in the presence of the wax inhibitors.  After 72 h, the thickness reduced 35 % in PI-A and 80% PI-B.  The wax content in the presence of PI – B (38%) is significantly higher compared to PI-A (11%) and NO PI (11%).  In turbulent flow, the deposit thickness decreases more than 2.5 times compare to laminar flow with and without inhibitors.  After the 72 h, the thickness reduced 45 % in PI-A and 85% in PI-B.  The wax content in the presence of PI – B (40%) and PI-A (25%) increases significantly compared to NO PI (18%).  The paraffin inhibition efficiency was calculated based on the wax mass.  PI-B is more effective in overall wax mass reduction compared to PI-A in both laminar and turbulent flow.