Had The Gasoline Cloud Caught Hearth
LONDON/PARIS, Sept 5 (Reuters) – A corrosive drilling fluid that triggered the North Sea’s worst gasoline leak in 20 years could threaten similar deep-sea wells across the world, and operator Total has already warned Shell that its nearby Shearwater area may be at risk.
The corrosive fluids implicated in the leak at Whole’s Elgin field, such as calcium bromide, are commonly used in such deep-sea wells, and specialists worry a recurrence as operators, under pressure to offset declining output from standard reservoirs, flip to deeper, hotter and better stress fields.
“Bromide brines have been utilized in hundreds of wells since their introduction in the 1980’s,” John Downs, a chemical engineer who runs his personal consultancy group, told Reuters. “An intensive effectively restore programme could also be wanted if the stress corrosion cracking attributable to bromide brine in Elgin can be occurring elsewhere.”
So nervous is Complete about recurrence in the Elgin area itself, it has plans to kill at least 10 different wells in the complicated as effectively as the one that leaked, which might value greater than 1.5 billion pounds ($2.34 billion) to change.
The North Sea is host to the very best variety of excessive-stress, high-temperature (HPHT) reservoirs of any mature oil and gas producing basin.
Complete UK chairman Patrice de Vivies instructed Reuters he had cooperated significantly intently with Royal Dutch/Shell when sharing information on the causes of the leak.
“With Shell we have now shared even more as they have a neighbouring subject, Shearwater, meaning they probably have, maybe, not equivalent, however comparable problems,” de Vivies said.
Like Elgin, Shell’s Shearwater area is fed by a HPHT reservoir the place temperatures can reach 140 degrees Celsius.
Shell declined to remark.
At peak output, Elgin and Shearwater account for more than a tenth of British coal fuel manufacturing. Elgin restarted this yr.
Any signs of one other Elgin could warrant wider investigations into the results of fluids utilized in HPHT wells, doubtlessly resulting oil refinery plant design pdf yahoo in the killing of extra wells and upsetting plans to squeeze extra from the North Sea.
The latest revival within the North Sea’s fortunes hinges on investment in HPHT fields. They’re additionally widespread off the coast of Brazil and in the Gulf of Mexico. The business has had to adapt the materials and fluids oil refinery plant design pdf yahoo it uses to cope with the treacherous situations.
Complete’s own investigation into the causes of the leak stay incomplete, although the sphere resumed output in March, with the blessing of Britain’s Well being and Security Govt (HSE).
“We hope that the laboratory can be in a position by the top of the year to reproduce the phenomenon,” de Vivies said.
Drilling engineers, gear manufacturers and chemical specialists say the long-time period consequences of exposing well casings to bromide-based mostly fluids are poorly understood, and some corrosive bromide fluids have already been banned.
“It’s an operational well, and there are lots of of thousands of those on the market, and any one in all them at any time potentially may suffer from the kind of problem Elgin has apparently had, so we need to learn about it as an industry,” said Liane Smith, founding father of nicely integrity specialist Intetech, not too long ago acquired by Wooden Group.
The G4 effectively within the Elgin field leaked for a month and a half, creating a huge cloud of flammable gasoline above the platform about 150 miles (240 km) east of Aberdeen in Scotland.
The leak pushed up gasoline costs and minimize UK provide by 7 p.c. An air and sea exclusion zone was imposed as personnel were evacuated from the world. Had the fuel cloud caught fireplace, the results would have been devastating.
Whole has mentioned the leak was brought on by a corrosive reaction between calcium bromide used to finish the well and grease within the pipework, which below high strain cracked the piping. The French agency described it as a “distinctive event”.
Calcium bromide is not generally regarded as corrosive and continues to be widely used in the North Sea, but Reuters uncovered a variety of historic circumstances in which chemically related fluids known as halides, resembling zinc bromide and calcium chloride, have corroded pipework.
Halide fluids, often called brines, can react with oxygen, carbon dioxide or hydrogen to kind a corrosive substance, particularly in deep wells comparable to Elgin the place temperatures can attain 200 levels Celsius.
“Bromide belongs to the same group as chloride, and so there may be all the time the danger of halide cracking of inclined steels. If the steels used are prone to chloride cracking, they are going to even be susceptible to bromide cracking,” stated Paul Rostron, professor of corrosion chemistry on the Petroleum Institute in the United Arab Emirates.
In 1999 piping in a properly on the HPHT Erskine discipline, operated at the time by Texaco and now by Chevron, cracked after calcium chloride reacted with air to corrode the steel.
Zinc bromide can be known to be more and more corrosive at high temperatures and its use is banned in the North Sea because it is considered dangerous.
“Zinc bromide and different bromides are highly corrosive to any form of steel it comes into contact with,” stated guide Downs.
Total has explained how fuel got into the Elgin well, however the company has stayed silent on the way it breached three additional effectively partitions after its initial point of entry.
Industry insiders wish to see a wider discussion in petroleum journals and at conferences. If a situation has been discovered during which calcium bromide turns into dangerously corrosive, the data have to be shared, they mentioned.
“They need to inform us what we want to maintain out of our wells in order that we do not stupidly go and do the identical factor once more,” a corrosion engineer told Reuters. He declined to be named lest his comments affect his relationship with purchasers.
Complete says it has shared the knowledge with operators.
“Earlier than we can publish scientific papers we want to reproduce what happened in a laboratory,” Total’s de Vivies mentioned.
Complete Chief Executive Christophe de Margerie stated: “The ultimate conclusion hasn’t yet been released as a result of it is not but over, and there are talks to grasp every thing that happened and every little thing that could occur in the future.”
Britain’s HSE and Total have performed separate investigations into what occurred at Elgin.
The HSE investigation will soon be sent to authorities in Scotland the place a decision will be taken on whether to prosecute Complete over the incident. Until such time, the HSE investigation can’t be launched, a spokesman from the watchdog stated.