ICON was engaged at an early stage of the platform design to conceptualise and confirm feasibility of the floatover method. The design incorporated all the necessary features to allow both crane barge or floatover installation. The final installation method was then chosen on the basis of lowest risk and cost.

The decision to proceed with the floatover method was made on 15 November 2002, the installation occurred five months later. ICON carried out all the engineering associated with the floatover, supervised loadout jointly with Murphy’s chosen fabricator in Lumut and performed the offshore installation. The project represents the first of a series of minimal deck floatover installations planned by Murphy in Malaysia.

The WP-PA topsides in jacking position for the floatover installation

To achieve the necessary clearances over the wellheads, the deck was cantilevered high off the barge bow on a 6m deep truss. Four hydraulic rams allow the deck to be raised an additional 3.5 m above the truss. The rams allowed set-down to be achieved with minimal barge ballasting in a very short time frame, minimising installation weather risk and docking loads. The deck was skidded inboard during marine transport. The various hydraulic docking and lowering systems were custom designed and supplied by ICON.

The barge anchoring, positioning, floatover and docking operation was completed within eight hours of the barge arriving in the field.

A view of the floatover operation from the barge deck: the wellhead platform jacket is white

The floatover method is cost competitive compared to traditional crane barge installation methods. The decoupling of the project schedule from the availability window of a crane barge is another significant advantage of this method.

The West Patricia WP-PA wellhead platform and barge following floatover installation