Raroa main wharf

OMV RAROA SURFACE COATING REFURBISHMENT

Summary

A rare landfall by the FPSO vessel Raroa in late 2013 was driven by the need to carry out important maintenance works, including resurfacing substantial areas of the ship’s sides. Intergroup was selected to do the surface cleaning and coating work as few companies could take on such a large project, as well as meeting strict time deadlines, physical difficulties and strict environmental conditions.

Despite these and other daunting challenges that arose during the project, Intergroup delivered the completed project a day early and on budget, with zero H&S or environmental incidents.

Time and environmental constraints put pressure on delivery

The Floating Processing, Storage and Offloading (FPSO) vessel Raroa has been moored on the Maari oilfield since late 2008. In that time, rough weather and regular production operations have resulted in an accumulation of wear and tear on the ship, which required maintenance.

Needing work on some critical structures, including replacement of the FPSO’s 45T bow swivel, the Raroa was berthed at Port Nelson for a two-week period. To coincide with this landfall Intergroup was contracted to carry out a substantial area of surface coating refurbishment to repair damage and remove corrosion from the outside of the hull.

Intergroup deployed a team of up to 12 personnel on the project over a 12 day period, working extended hours to ensure no delay to Raroa’s schedule was caused by the surface protection programme.

Zero emission mandatory requirement

Strict environmental conditions, on top of the tight timeframe, put intense pressure on Intergroup and its personnel onsite.

The key environmental requirement was that zero contaminants could be emitted to air or water in the port. Although seemingly impossible, Intergroup’s specialised water blasting plant – the Hydrocat, a robotic ultra high pressure (UHP) vacuum unit – was equal to the task.

The Hydrocat is a fully enclosed high pressure water blasting system that recycles the water it uses while removing any particulate material from the cycle, leaving the finished surface clean and dry, ready for painting.

Because of these performance characteristics the Hydrocat became the only permissible method of surface preparation consented to be used in Port Nelson.

Where the main Hydrocat machine couldn’t be used due to space constraints, a small handheld unit, an attachment to the Hydrocat working off the same sealed vacuum system was used.

Creative problem solving required

As repainting works were to be carried out on both sides of the Raroa, it was planned that after five days the vessel would be turned around, so access from the wharf could be maintained.

Unfortunately, the turnaround couldn’t be carried out, so Intergroup’s on-site management together with the Port Nelson Harbourmaster and MODEC (Raroa’s owners) representatives had to quickly develop an alternative approach.

The solution they developed for establishing a safe work platform comprised a barge, ballasted with fresh water, a fire pump and three scissor-lifts bolted onto the deck of the barge.

The three scissor-lifts were set at different levels, so each operator worked on a different height band as the worksite moved along the ship (the barge being pushed by a tug). To comply with environmental consents coating was applied by power rollers using airless spray units. However to further ensure no particulate matter from dispersing into the air or water, each scissor-lift was fully enclosed in fabric.

Intergroup worked within HSE standards as prescribed by national and local authority legislation, NZ Maritime Law and OMV’s HSE Manual. Throughout the barge-based works period the operators were monitored by a lift-controller, who operated the three scissor-lifts, and a safety watch person. A safety boat was on site at all times while the harbour-master’s launch was kept on standby.

Works were closely monitored by an environmental officer from the port, the Harbour Master, a specialist from the paint suppliers and third party H&S consultants. The site was visited periodically by an environmental officer from Nelson City Council.

As a result of this stringent attention to managing hazards, the project was delivered with zero H&S incidents and zero environmental incidents, and Intergroup is now the only company permitted to undertake this type of operation in Port Nelson.

The Floating Processing, Storage and Offloading (FPSO) vessel Raroa is a converted oil tanker, approximately 250 metres long and 40 metres wide.
The Raroa was brought to New Zealand in 2008 and has been moored on the Maari oil field site since then. It sits about 1.5 kilometres from the wellhead platform (WHP) Tiro Tiro Moana.
The Raroa’s main function is to separate the raw production from the wells into oil, gas and water and then store oil for offloading to a conventional tanker. It has storage capacity for about 600,000 barrels and a daily production capacity of up to 40,000 barrels of oil per day.