Plantwide control of an oil production network

Abstract

In this paper, we consider Real-Time Optimization (RTO) and control of an oil production system. We follow a systematic plantwide control procedure. The process consists of two gas-lift oil wells connected to a pipeline-riser system, and a separator at the topside platform. When the gas injection rates are low, the desired steady flow regime may become unstable and change to slug flow due to the casing-heading phenomenon. Therefore, a regulatory control layer is required to stabilize the desired two-phase flow regime. To this end, we propose a new control structure using two pressure measurements, one at the well-head and one at the annulus. For the optimization layer, we compare the performance of nonlinear Economic Model Predictive Control (EMPC), dynamic Feedback-RTO (FRTO) and Self-Optimizing Control (SOC). Based on dynamic simulations using the realistic OLGA simulator, we find that SOC is the most practical approach.