A Flow Loop to Study Wax Deposition in Pipelines

Wax deposits are formed in subsea well tubing, surface flow lines and production equipment of crude oil or gas condensate as these fluids are cooled due to heat loss to the surrounding cold sea water. These solid deposits interfere with production and hence, influence the economy of a field. In this paper we report the design of a flow loop apparatus that can be used to conduct continuous wax deposition experiments under different flow conditions and at variable temperature differentials. A data acquisition system was used to record the temperature and pressure readings. The flow apparatus successfully simulated the cooling process that occurs in subsea oil pipelines transporting waxy fluids. The gradual reduction in hydraulic diameter due to wax deposition was monitored using the pressure drop method. Wax deposition occurred initially at a high rate and then followed an asymptotic behavior. The designed set-up can be employed to quantitatively predict the effectiveness of wax inhibitors under simulated field operating conditions.