Current issues and technologies for the reassessment of existing offshore installations

The statutory requirement to prepare safety cases for United Kingdom offshore platforms following the Piper Alpha disaster, the extensive damage to offshore platforms in the Gulf of Mexico caused by Hurricane Andrew and the desire to extend the operational life of hydrocarbon production platforms throughout the world has led to several important industry initiatives concerning requalification and reassessment of offshore platforms. This paper describes the development of a new industry reassessment. guideline document, the philosophy within the guidelines and the technologies available for reassessment. In particular, the availability of validated non-linear system ultimate strength collapse analysis computer software is revolutionizing the reassessment process by being able to take advantage of the system reserve and residual strength above the individual component design capacity level. However, there are problems in the application of these advanced techniques and there are several generic issues concerning acceptable levels of risk, the scope and methodology of reassessment and the development of international standards for reassessment. The paper draws out these issues and describes industry initiatives that are working towards their resolution.