Nonlinear Model Predictive Control of an Oil Well with Echo State Networks

Abstract

In oil production platforms, processes are nonlinear and prone to modeling errors, as the flow regime and components are not entirely known and can bring about structural uncertainties, making the design of predictive control algorithms a challenge. In this work, an efficient data-driven framework for Model Predictive Control (MPC) using Echo State Networks (ESN) as the prediction model is proposed. Unlike previous works, the ESN model for MPC is only linearized partially: while the free response of the system is kept fully nonlinear, only the forced response is linearized. This MPC framework is known in the literature as the Practical Nonlinear Model Predictive Controller (PNMPC). In this work, by using the analytically computed gradient from the ESN model, a finite difference method is not needed to compute derivatives as in PNMPC. The proposed method, called PNMPC-ESN, is applied to control a simplified model of a gas-lifted oil well, managing to successfully control the plant, obeying the established constraints while maintaining setpoint tracking.