The Scope
Apache’s Varanus Island Compression Project (VICP) was required to ensure ongoing domestic gas supply from offshore fields with decreasing pressure via the existing facilities on Varanus Island.
Apache requested Cube to redesign the seafastening for several modules for the sea voyage from Batam Indonesia to Henderson in Western Australia to facilitate quicker and efficient mobilisation and demobilisation of the transport vessel and supporting services. The total cargo weighed approximately 1500 tonnes.
Apache required the seafastening design to be simple and smart and to accommodate self-propelled mobile transport (SPMT) load-out. In addition, Apache brief was to maximise prefabrication and minimise on vessel fabrication during mobilisation. Apache required shop and assembly drawings. Cube was required to re-perform the transport analysis for the improved design and interface with Apache, the transport contractor, vessel owner, fabrication yard and marine warranty surveyor.
Apache required design to facilitate discharge at Henderson, land transport by SPMT, temporary storage and reuse.
Apache required Cube to work closely with Apache and for Cube to lead and develop the design and mobilisation sequence.
The Outcome
The poor original design and the late change in seafastening designer created a significant schedule challenge. To protect Apache’s schedule, Cube prioritised and generated shop detailing drawings of steel parts so material supply could start. Assembly and general arrangement drawings then followed.
Cube’s design met Apache’s brief and marine warranty surveyor requirements. Compared to the original seafastening design proposed, Cube reduced the steel weight by 50 percent and reduced the welding required by 80 percent. Cube further recommended using prefabricated items in preference to a stick build on the transport vessel. In summary, Cube’s recommendation and design ensured efficient (so cost effective) mobilisation and discharge operations.
