Review of jack-up inspection and repair practice

Abstract

A review and assessment of current inspection and repair practice for jack-up drilling rigs is presented in this paper. The objective of this study was to identify how inspection and repair strategies for jack-ups are currently formed and how these can be improved through the use of more rational and systematic approach using reliability based inspection scheduling techniques. Drilling contractors, Classification Societies and Designers were contacted to provide information for this review. Jack-up characteristics which relate to their structural configuration and modes of operation directly affect the current inspection practice and are reflected in the prescriptive nature of inspection requirements. The information obtained from this review study points towards the conclusion that the present practice is working satisfactorily, and while there appear to be no major problem areas, there is significant room for improvements. Current practice is prescriptive in nature and although it may be adequate it is not geared towards maintaining a consistent level of reliability across the structure and achieving maximum efficiency. Some areas of concern relating to current practice are highlighted in this paper together with recommendations for improvements through the use of reliability based inspection scheduling techniques which provide a more rational basis for selection and scheduling of inspections. Further work that would be required to develop appropriate optimised inspection tools and improved inspection planning guidance are also discussed in this paper.