Peter Milne: The West Australian: Saturday, 9 February 2019 1:13AM

Shell has struggled through a series of safety missteps as it readies its cutting-edge Prelude floating LNG vessel for production.

Shell reported 17 incidents to the offshore safety regulator NOPSEMA between May and October 2018 that the regulator classified as dangerous occurrences.

The reports, obtained by WestBusiness through a freedom of information request, show the challenges facing hundreds of WA workers that have helicoptered about 500km back and forth between Broome and the 488m-long giant since it arrived from South Korea in July 2017.

One difficulty with floating LNG vessels is that an LNG carrier must berth alongside as the two vessels bob about in the sea, unlike floating oil production facilities that offload oil to a tanker a safe distance away through long flexible hoses.

In early May 2018 Shell tried to bring the LNG carrier Gallina alongside.

A tow rope to a tug failed when the 290m-long carrier was just 50m from Prelude and the operation had to be aborted.

That problem was caused by a tow rope that was incorrectly assembled.

Nine days later something as trivial as wrongly shaped plastic thwarted another attempt to load LNG on to Prelude.

It was thought the Gallina was safely secured to the Prelude by 16 mooring lines that ran through guides on the Prelude called fairleads. As the crew prepared to connect the LNG loading arms a mooring line failed and the Gallina was released and pulled away.

Afterwards it was found that all 16 lines had been significantly damaged by rubbing against sharp edges of nylon liners in the fairleads.

This seemingly trifling detail could have caused a “complete mooring failure” with “potential for serious consequences” if it had occurred later while LNG was being transferred.

Two weeks later the Gallina successfully offloaded its LNG and Prelude had gas to power itself and test its processing plant.

However, having gas on board the Prelude increased the risks Shell had to manage.

A flange leaked near the LNG loading arms as super-cold -162C LNG sitting at the bottom of a pipe caused it to contract and bend.

Another type of gas, hydrogen sulphide, was released when construction debris from the Korean shipyard was being removed from a tank and the area was evacuated.

In July a fire damper intended to keep gas from entering the air-conditioning system for the accommodation quarters failed to close when tested but was repaired quickly.

In August, Prelude lost all its power supply when a pump sending water to a gas-fired boiler tripped.

All workers on the Prelude and the attached 750-bed Posh Arcadia floating hotel went to their muster stations as the diesel emergency generators powered up to supply essential services.

But a transformer failed and the system to cover the deck with firefighting foam was left without power and unable to operate.

Other problems included a test of a system to cover the top of LNG tanks with a deluge of water in an emergency that found it delivered only half the planned amount of water as the system used undersized valves.

There was a small fire when dust in an oxygen cylinder valve ignited, leading to a muster of all personnel.

Newly installed insulation on a hot high-pressure steam line was seen smouldering and when the insulation was pulled away it caught fire. The insulation had been secured by combustible tape.

A Shell spokeswoman said the company had a rigorous program on Prelude to identify and manage risk in a controlled way.

“It is not unexpected for issues to arise during this phase of a project and it is standard practice to notify NOPSEMA,” she said. “We are proud of our safety and reporting culture.”

She said Shell encouraged workers to raise safety concerns.

TEETHING PROBLEMS

2017

July: Prelude arrives from Korea

2018

May: Tow line to tug fails, mooring lines fail

June: LNG loaded onto Prelude, gas leak, flood detection not working

July: Hydrogen sulfide leak, flooded machinery room, fire dampers did not close

August: No power to fire-fighting foam

September: Smouldering insulation

October: Small fire

December: 750-bed accommodation vessel for additional workers leaves, wells opened and gas flows to Prelude.

2019

February: Preparing for first export of condensate

SOURCE

RELATED

The links below are to a series of articles, many triggered by a well-placed whistleblower directly involved in the pioneering Royal Dutch Shell Prelude project. Includes articles by Mr Bill Campbell, the retired distinguished HSE Group Auditor of Shell International and another retired Shell guru with a track record of spotting potential pitfalls in major Shell projects. read more