Empirical Stability Margin Assessment and Robust Gain Scheduling for Choke Pressure Control in Deepwater Wells

Classical stability analysis can be difficult to apply to high-order systems due to its reliance on the availability of explicit analytical models. An example of high-order systems that stand the risk of instability with potentially catastrophic consequences but where little formal stability analysis has been applied is the pressure dynamics in deepwater oil and gas wells. This work examines the frequency response of realistic deepwater wells and analyzes how high-order interactions, well configuration, and operating points affect stability. We present a workflow to empirically determine interpretable stability margins for choke pressure control systems on challenging wells, and validate the approach through high-fidelity simulations. Finally, we demonstrate how the workflow can be exploited to generate a robust gain-scheduled choke pressure controller.