Condition-based maintenance method for multicomponent system considering maintenance delay based on remaining useful life prediction: Subsea tree system as a case

Maintenance resources and personnel may not arrive in time after formulating a maintenance strategy due to the particular working environment and poor accessibility for multicomponent systems. A condition-based maintenance (CBM) method considering maintenance preparation delay based on remaining useful life (RUL) prediction is proposed. Maintenance preparations under normal and emergency conditions are considered. Inspection time is dynamically set based on the maintenance preparation time and the RUL prediction result. At the inspection time point, RUL for each component in the multicomponent system is predicted based on offline inspection data according to the degradation trend, which is simulated by combining Gamma and Poisson processes. The next inspection time can be determined subsequently. A threshold based on RUL prediction results is set as the maintenance standard to evaluate the maintenance effectiveness. Inspection interval, safety threshold, and maintenance threshold are optimized by minimizing the maintenance cost. A case study of the subsea tree system for offshore oil and gas development is conducted to demonstrate the application of the proposed CBM methodology. • A CBM method considering maintenance preparation delay based on RUL is proposed. • Maintenance preparations under normal and emergency conditions are considered. • Inspection time is set based on maintenance preparation time and predicted RUL.