BARROW ISLAND CATHODIC PROTECTION SYSTEM — DESIGN, INSTALLATION AND COMMISSIONING

Abstract

The Barrow Island oil field, with an area of about one hundred square kilometres containing over six hundred wells, presents an engineering challenge of vast magnitude in the protection of investment in the wells and their casings against the destructive process of corrosion. The growing incidence of casings leaks and escalation in the costs of repairing externally corroded casings provided the impetus for pilot scheme studies and subsequent design and installation of an impressed current cathodic protection system on a scale not previously undertaken in Australia.

Data obtained from pilot scheme tests carried out in the latter half of 1979 established the basis of a feasible design. Detailed design and installation through 1980-81 was followed by commissioning of the first area of the system early in 1982.

Design of the cathodic protection system was tailored to the local field conditions; the design was modified when necessary as installation and commissioning difficulties arose. Several minor operational problems encountered to date are still to be resolved.

The total initial outlay of $5.7 million should result in minimum cumulative savings in well casing repair costs of $15 million over the next 15 years.