Mina Abdullah Refinery Sea Island Structure – Life Assessment
Rendel was appointed to undertake a life assessment of the existing structure and mechanical and electrical installations. The works included a full inspection of this offshore sea island structure used for berthing 250,000 dwt tankers while loading crude oil and product from the Mina Abdullah Refinery complex. The structure comprises a series of linked piled jacket structures forming the loading platform and berthing and mooring dolphins.
The inspection included visual inspection as well as detailed wall and marine growth thickness measurements, cathodic protection potential measurements and MPI of a selected number of welds. in addition, Rendel carried out visual and performance inspections of all topsides equipment and evaluated a replacement and repair schedule together with detailed cost estimates to allow the company to review the business case for future refurbishment.
In parallel with the site inspection the design team produced a series of Finite Element (FE) models of the structures and carried out an independent assessment of the design loads and the stresses in the as-built structure.
The FE models were constructed using as-built dimensions, but the code checking of the output made allowance for measured corrosion and predicted corrosion extrapolated over the next 15 years of the structures’ life.
Although the structures were found to be generally in very good condition, it was possible to identify those members most at risk due to high stress or cyclic loading. Recommendations were made for repairs and increased maintenance inspection at the most critical areas and for maintenance of the paint and cathodic protection system.