Real-Time Physics-Based Accumulator Leakage Estimation for Hydraulic Integrity Monitoring of Subsea Blowout Preventer Systems with Signal-Based Consistency Analysis

Subsea blowout preventer (BOP) hydraulic control systems are safety-critical subsystems whose performance directly affects well control capability and emergency actuation reliability. Maintaining hydraulic integrity is essential because leakage-induced degradation can reduce stored actuation energy and compromise pressure delivery during critical operations. This paper presents a physics-based real-time monitoring methodology for accumulator leakage estimation in subsea BOP control systems using offshore pressure measurements. The approach estimates cycle-level leakage rates from hydraulic power unit pressure histories by analyzing pressure decay behavior during discharge cycles and applying recursive least-squares estimation (RLSE) for the adaptive tracking of leakage dynamics. To further assess whether the estimated leakage behavior reflects observable hydraulic system dynamics, a complementary signal-based consistency analysis is performed using features derived directly from the pressure measurements. The results indicate that the leakage states identified by the RLSE method correspond to statistically distinguishable and physically interpretable pressure patterns, supporting cross-method consistency. Because the methodology relies only on routinely available pressure measurements and requires no additional subsea instrumentation, the proposed framework provides a deployable approach for real-time hydraulic integrity monitoring and condition-based maintenance support.