This paper describes an inspection and maintenance planning methodology that incorporates advanced reliability analysis with fracture mechanics based on limit state function including reliability updating after inspection or repair and considers the life reduction of tubular joints submitted to fatigue so that is possible to monitor the condition of the joints during its working life. Furthermore an application for a fixed marine platform installed in the Mexican sector of the Gulf of Mexico is presented. This application was carried out using the customised system for the Instituto Mexicano del Petroleo an took into account the most critical joints of the marine platform and the result was an optimal inspection program based on reliability index and expected costs of inspection.

INTRODUCTION

As facilities for oil exploitation in the Mexican sector of the Gulf of Mexico become older maintenance of marine platforms plays an important role and becomes more indispensable to ensure structural integrity and to warranty production. An important factor to maintain safe production is by means of the application of an appropriate inspection strategy in order to reduce the likelihood of failure and maximise the effective use of subsea resources. Thus far marine platforms III the gulf of Mexico have been inspected considering the criteria of being inspected totally during a period of five years. The frequency and areas to be inspected have been a matter of engineering discussion and finally international codes based on experience and judgement are applied. However, using a methodology developed from structural reliability and fracture mechanics it is possible to enhance and rationalise this approach, targeting inspections to the critical zones of structures. Such new methodology increases effectiveness of subsea work by eliminating unnecessary inspections and targeting maintenance. Consequently, the costs of inspection are minimized and at the same time the likelihood of failure is kept within acceptable limits.

This content is only available via PDF.
You can access this article if you purchase or spend a download.