Offshore Oil Production, Three-Phase Separation, Disturbance Damping, Adaptive Control, VS-MRAC. 

This work focuses on the control of three-phase separators in offshore production units, an element of utmost importance for the efficiency of the oil production process in marine environments. The traditional control approach with PI SISO controllers, widely adopted in the industry, has significant limitations, such as the inability to effectively deal with uncertainties in system parameters, unexpected disturbances and the mitigation of load swing, which is a critical drawback. Additionally, attempts to improve control through predictive techniques and multivariable PI control also face challenges in absorbing plant disturbances and optimizing overall separation efficiency. It is in this context that the Variable Structure and Reference Model Adaptive Control (VS-MRAC) technique emerges as a promising approach to overcome these limitations. This work proposes the application of VS-MRAC in the control of offshore three- phase separators. The main characteristic of this technique is its adaptability to changes in system conditions and ability to deal with uncertainties in system parameters, making it robust in the face of disturbances and operational variations. VS-MRAC's adaptive and robust approach is essential for meeting the specific challenges of offshore operation, positioning it as a solid and promising choice for effective control of critical systems in the oil and gas industry in marine environments.