Designing out fabric maintenance on a new offshore development using safety principles

Abstract

Most individuals would love to own a car or boat that required little or no maintenance. Woodside is desirous of the same for the 50 000 t Scarborough floating production unit (FPU) located 450 km offshore. This would be beneficial, not just from a cost perspective but also for all the additional benefits associated, such as safety and hazard risk reduction. Woodside's Australian operations typically spend >$300M annually on inspection and maintenance of their assets to maintain them in a safe operating condition. The cost of maintenance at operating offshore facilities is approximately 100 times that of onshore fabrication, with these costs particularly high due to the complexities of conducting maintenance on live hazardous plant. For example, reactive offshore coating maintenance offshore costs ~$3000/m2, preventative offshore coating maintenance ~$1000/m2 and onshore steel fabricator/blast and painting ~$30/m2. To achieve the goal of minimal maintenance, Woodside have been applying a hierarchy of control principles to the Scarborough FPU. This has delivered the following outcomes. (1) Elimination of steel, using fibre-reinforced plastics, which has replaced 10 000 m2 of walkway gratings and stair treads and 3.5 km of handrails. (2) Substitution of steel using corrosion-resistant alloys for pressure equipment, with a reduction in maintenance, chemicals and inspection. (3) Substitution of coated tertiary structural steel with uncoated stainless steels. (4) Specification of higher integrity coatings (glass-fibre reinforced epoxies). (5) Providing additional dedicated resources for assurance during construction that these new controls are implemented correctly. (6) Providing dedicated inspection locations for remote internal inspection to preclude human entry.