Deterioration Models for Offshore Jacket Platforms
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Solution Overview
Problem
There is a scarcity of published literature on modeling residual service life for offshore jacket-type platforms, which hinders accurate estimation of their performance and maintenance planning, as existing methods rely heavily on inspection records that are often scarce.
Innovation Solution
The development of time-dependent deterioration models using stochastic Markov-chain and stochastic-mechanistic approaches, which estimate the structural health condition and rate of deterioration of offshore jacket platforms without requiring ongoing monitoring or real-time sensor inputs, by employing corrosion wastage models and Monte Carlo simulations to predict maintenance, repair, and rehabilitation actions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If deterioration models are developed based on inspection records, then accurate estimation of platform performance is improved, but the method becomes inapplicable when inspection records are scarce
Solution Approach 1:
The patent introduces probabilistic methods as an intermediary approach between inspection records and performance estimation. When inspection records are scarce, the methodology uses probabilistic deterioration models that incorporate available limited data with statistical distributions to bridge the information gap, enabling performance estimation without requiring extensive inspection records
Solution Approach 2:
The patent transforms the estimation approach by changing from deterministic models (requiring extensive inspection data) to probabilistic models. This parameter change allows the system to work with uncertain and limited data by incorporating probability distributions for deterioration rates and condition states, making the methodology adaptable to platforms with scarce inspection records
2Productivity
If probabilistic methods are used for planning inspections, then maintenance planning is improved, but the complexity of the modeling process increases
Solution Approach 1:
The patent segments the deterioration modeling process into distinct components: condition state definitions, transition probability matrices, and deterioration rate models. This segmentation allows each component to be developed and calibrated independently, reducing overall model complexity while maintaining the benefits of probabilistic maintenance planning
Solution Approach 2:
The patent implements self-service through automated probabilistic modeling that can be applied systematically across different platform types. Once the probabilistic framework is established, it can be reused with minimal customization for different platforms, reducing the complexity burden while improving maintenance planning efficiency across multiple assets
Data Source
AI summary
Methods of determining an offshore jacket platform’s condition including determining a geometry, a plurality of loads, and a material composition of an offshore jacket platform; obtaining a base shear at collapse when the offshore jacket platform is intact; calculating a residual resistance factor; determining a criticality factor for each of a plurality of members on the offshore jacket platform; determining a structural health condition state; determining the probability of deterioration; and modeling a rate of deterioration. Another aspect of the disclosure includes methods of determining an offshore jacket platform’s condition in case of lack of inspection records including selecting a corrosion wastage model for splash zones and immersion zones, identifying distribution parameters for the legs and bracings of the jacket platform; determining a structural health condition state for leg and bracing; aggregating probable structural health condition states; and modeling a rate of deterioration of the offshore jacket platform.