Design for Reliability: Enabling Enhanced Condition Monitoring in All-Electric Subsea Systems

Abstract The All-Electric Subsea (AES) approach represents a significant advancement in the Oil and Gas industry, aiming to replace traditional hydraulic and electro-hydraulic systems with electromechanical solutions that offer numerous benefits, including reduced installation (CAPEX) and operational (OPEX) costs, smaller environmental footprint, and better condition monitoring. Among the emerging technologies, electro-hydrostatic actuators (EHAs) stand out for their potential to combine the advantages of AES with the high power density, overload protection, and fail-safe functionality inherent in conventional electro-hydraulic systems. Most currently installed subsea equipment relies on hydraulic or electro-hydraulic control systems, making a rapid transition to AES solutions challenging. A key enabler for accelerating this transition in existing "brownfield" installations is the development of compatible electrification technologies. In this work, a portfolio of subsea electric actuation system featuring standardized torque and push tool interfaces compliant with relevant norms, such as API 17H, is presented. These solutions can be retrofitted onto subsea valve interfaces, both on platforms and in subsea environments, using ROVs. The adoption of AES technology also enhances condition monitoring capabilities, enabling a deeper understanding of equipment behavior. For instance, parameters such as valve friction and bore pressure can be estimated using embedded algorithms within the subsea valve actuators. This paper presents a novel method for estimating critical parameters of subsea production valves by integrating a condition monitoring algorithm into the application software of the presented actuation systems embedded controllers. The proposed algorithm was validated through simulations and real-world experiments using the eSEA DRIVE and a 5 1/8-inch gate valve under hyperbaric conditions, with environmental pressures up to 450 bar and production pressures up to 740 bar. The results demonstrate the algorithm's effectiveness in monitoring valve parameters and operational conditions, highlighting its potential to enhance the reliability and efficiency of AES systems in subsea applications.