Mackerel and Tuna Platforms

1. A template with an integral jacket cap to elevation (+)17 m.


2. Launching the template with essentially all sleeve piles pre -installed


3. Integral buoyancy tanks for uprighting the template, and use for permanent consumables storage


4. Installation of construction equipment on the template for drilling and grouting operations to make these operations as independent of weather and floating construction equipment as possible

During Mackerel platform construction, only 19 per cent of the time was lost to weather down-time. This compares favourably with the historical average of about 50 per cent weather down-time experienced with the previous Bass Strait installations. In addition, while pile work was in progress the barge was used to complete the partially finished Mackerel pipeline and to set the riser without interrupting platform construction.

Design improvements developed for this project were successfully proven in reduced weather down-time statistics and improved construction efficiency. A thorough and deliberate approach to design, which was enhanced by the integrated design concept, resulted in a practical and economical design. Incorporating the latest technology, the design was a balanced compromise of construction, drilling, production, and service system requirements. The difficult drill and grout pile installation work was completed smoothly and relatively trouble free, due largely to extensive early planning.

The new generation Bass Strait platform design is considered to be a significant technological improvement, and a similar design of this type is now underway for a new gas field development in 45 m of water. It is estimated that the design is responsible for construction savings in the order of seven weeks derrick barge time per platform.

Australian Academy of Technological Sciences and Engineering