Offshore Inspection Cost Reduction by Inspection Planning Based on Survey Records, Fatigue and Reliability Analysis

An approach to identify fatigue sensitive joints to be considered in an inspection programme is presented. Joint selection is based on inspection records, fatigue and reliability analysis. Fatigue analysis is used to identify fatigue sensitive tubular joints, thus reliability analysis and inspection records are used to assess the joint selection. The objective is to reduce the number of inspected joints whilst maintaining the platform risk level within acceptable limits. A relation between the reliability index β, a weighted average stress range value and tubular joint geometrical expressions is presented for the selection of joints for inspection. Experience obtained from inspection records is considered for an assessment of the joints selected for inspection. Cost reduction is determined from a comparison of this approach with inspection programmes applied in the past.