A Comprehensive Evaluation Model for Mobile Offshore Drilling Units Based on Lagrange-Optimized Combination Weights

Due to the diverse functions of supporting equipment and numerous operational parameters, offshore mobile drilling units are difficult to evaluate through a systematic and comprehensive quantitative approach. Based on an analysis of the hierarchical structure of key equipment functions, this study proposes a comprehensive quantitative evaluation model for operational capability of offshore mobile drilling units by integrating the Analytic Hierarchy Process (AHP) and the improved CRITIC method. To minimize the deviation between subjective and objective weights, the Lagrange multiplier method is employed for optimal weight combination. Taking mobile drilling platforms currently in service in the South China Sea as the research object, the evaluation criteria are identified to include four main aspects: rated platform capacity, actual operational performance, equipment failure rate, and economic efficiency. The case study results indicate that the evaluation method effectively synthesizes the distinct characteristics of both subjective and objective evaluations, thereby enhancing the scientific rigor and robustness of the decision-making process. The robustness of the proposed model was validated through comparative analysis. Furthermore, dynamic optimal selection charts under varying water and well depths are generated. These visual tools enable operators to identify the most suitable platform for specific operational scenarios, providing a scientific basis for engineering decision-making.