Anti-slug control based on a virtual flow measurement

Feedback control is an effective and economic solution to prevent slugging flow regimes in offshore oil production. For this, the opening value of a choke valve at the topside platform is usually used as the control input to regulate the pressure or the flow rate in the pipeline. Designing such a control system based on topside measurements, without subsea sensing devices, is preferred from a practical point of view. Controlling the topside pressure alone is difficult and it is not robust in practice, but combining the topside pressure and the flow rate results in a robust control solution. However, measuring the flow rate of a multiphase stream is challenging and requires expensive instrumentation. In this paper, we propose an anti-slug control solution based on a virtual flow measurement. This virtual flow is estimated without neither density nor phase fraction involved, but it gives satisfactory results for the stabilizing control. In particular, applying a cascade structure results in a robust and recommended solution. The performance of the proposed controller is demonstrated by simulation using the realistic OLGA simulator and by experiments.