Stability of severe slug flow in U-shape riser

Abstract

A typical challenge in the oil and gas industry when transporting hydrocarbon fluids, is the instabilities associated with the flow resulting from pressure and flow fluctuations. U-shape riser or platform to platform pipeline configuration also faces such difficulty and this negatively affects downstream facilities and production on the whole. This undesirable flow has stimulated several researches and investigation from time past in the quest to mitigate slugging. Active control scheme as a slug mitigation technique, operates at a greater choke valve opening than would be obtained using manual choking. This auspicious technique faces the challenge of having a controller that is robust and capable of producing the desired performance. A novel Inferential Slug Controller (ISC), an active control scheme, combines several topside measurement on a U-shape riser to produces a single control variable which is more sensitive to slug flow through a simple algebraic scheming. In this work, a method that can be used for slug control stability analysis was used to design an ISC. Further insight was drawn-out by performing several system stability analysis. The effectiveness of the proposed method was accessed using OLGA. The findings could possibly have consequences on the configuration and further expansion on the ISC technique.