The effect of a surfactant on slugs in a flowline-riser system

Pronk, E. J. (Delft University of Technology) | Ellepola, J. H. (Shell Projects & Technology) | Henkes, R. A. W. M. (Delft University of Technology / Shell Projects & Technology)



Based on the success of foam in subsurface applications it is of interest to investigate whether foam can also help overcome liquid management problems in surface flowline-riser systems. Therefore, flow experiments were carried out in the flow loop at the Shell Technology Centre Amsterdam. The facility consists of a 100 m long horizontal flowline (with 50.8 mm diameter) followed by a 16.8-m vertical riser (with 44 mm diameter). Air and water are the working fluids, and operation is at atmospheric outlet pressure. Foam is created by adding “Dreft™” (a dishwashing detergent) in various concentrations to the water/air flow. Experiments were taken both without and with foam. Various measurement techniques were used: differential pressure sensors, flow visualization, and Distributed Acoustic Sensors (DAS) (fibre optics). The focus is on (growing) slugs in the horizontal flowline, and severe slugging in the flowline-riser. It can be concluded from the small-scale lab experiments that adding a surfactant mitigates (growing) slugs in (nearly) horizontal flowlines, whereas the severe slugging cycle in a flowline-riser configuration cannot be broken.