Review of Slug Detection, Modeling and Control Techniques for Offshore Oil & Gas Production Processes

The current offshore oil & gas multi-phase production and transportation installations have big challenges related with the slugging flow: An unstable multi-phase flow regime where the flow rates, pressures and temperatures oscillate in the considered processes. Slug can be caused by different operating conditions and installation structures. The most severe slugs are often induced in long vertical risers or production wells, where liquid blocks gas at the riser/well base and correspondingly it causes the pressure to accumulate and hence originates the oscillating performance. There are many severe consequences to the production processes because of the slugging flow. This paper reviews some observed latest status and key challenges about slug detection, dynamical modeling and elimination of slugging flows. Mathematical modeling of slug has been used to investigate the slug mechanism and anti-slug control. Most of available models are based on mass-balance formulations, which often require sufficient data for reliable parameter tuning/identification. Slug elimination and control have been investigated for many years and there exist many solutions to eliminate the slug, but some of these methods can simultaneously reduce the oil & gas production, which is a very big concern as the production rate is the key evaluation parameter for offshore production. We conclude that the slugging flow is a well-defined phenomenon, even though this subject has been extensively investigated in the past decades, the cost-effective and optimal slug modeling and control are still open topics with many related challenges.