The government gave Chevron the go-ahead in September to drill in the North Sea near Shetland, in spite of the US oil giant’s admission that its contractor's spill prediction software constantly crashed and was not a reliable predictor of how far oil could travel if an accident took place.
The news comes in a week that US investigations into BP's disastrous Deepwater Horizon oil spill hit the buffers, after an IT contractor firm refused to hand over access to its software.
Before the new North Sea drill, which continues to run without accident, Chevron admitted the serious computing problems in confidential documents sent to the Department of Energy and Climate Change, which approved the drill. A redacted version of the communications was released as part of a Freedom of Information request made by the Guardian newspaper.
The Oil Spill Information System (OSIS), from BMT Argoss and used by services firm Oil Spill Response, crashed repeatedly when Chevron attempted to run it to model a 20 day period. In the end, Chevron ran the Microsoft Windows-based system for 14 days only because it said “no usable information” could be gleaned from the full run.
The system is based on Eurospill, a simulation model developed with grants from the Department for Transport and the European Commission. On its website, BMT Argoss says the system is “a sophisticated tool for predicting oil spill transport and fate”, and builds on 30 years of research and 15 years of modelling technology development.
The modelling system was only able to predict what would happen for a fortnight, even though Chevron said that in reality it could take a further four weeks to cap a well, and even longer in bad weather or without access to the right equipment.
In an email to the Offshore Inspectorate, dated 7 September, Chevron said it was working “at the boundaries of modelling capability”.
According to the models used, a deepwater blowout at Chevron’s Lagavulin rig could spew over a million gallons of oil into the sea over the first two weeks, with the crude polluting most of the coast of eastern England and Scotland, as well as much of Norway and spreading as far as Iceland and Greenland.
The news comes as Transocean, the owner of the now-infamous Deepwater Horizon rig operated by BP, was found to have had a near-miss with one of its North Sea rigs used by Royal Dutch Shell. An internal Transocean report, seen by the BBC, shows that four months before the Gulf of Mexico disaster, the company experienced similar problems to those in the US but this time the crucial blowout preventer stopped an explosion.
Modelling software is increasingly being placed under the spotlight after US investigators indicated in a presentation that BP had ignored the safety recommendations of cement modelling software run by its contractor Halliburton, in a bid to save time and make the Deepwater Horizon rig operational quickly.
In Chevron’s North Sea drill, the oil firm said the spill modelling software usually crashed when left to run for long periods of time, adding that this was typical of standard industry systems.
The modelling “to some degree gives a potential indication of consequences that could arise”, it said. But the model was not effective for oil at depth, when it continues to spew, or when dispersant is applied.
Chevron sent the government final plans in early September, and these were approved by DECC on 30 September.
Secretary of state Chris Huhne said he was “satisfied that the project is not likely to have a significant effect on the environment”. DECC told the oil giant there was no need for it to provide a full statement detailing exact environmental risk.
Drilling began four days later. This week DECC said in a statement that Chevron had “adequately assessed” the potential impact of a spill.
Even though critically endangered wildlife species including minke whales, sperm whales and various species of dolphin were found in the area that could be covered by a spill, Chevron insisted an accident would only have a limited impact on them because they were good at swimming and would probably swim out of the way of the oil.
Speaking to the Guardian, environmental group Greenpeace lambasted the Chevron drill, which it said was approved “off the back of an unfinished computer model”.
Chevron, however, said its actions proved that its “first and greatest focus” was on preventing accidents.
The company added: “It is important to emphasise that spill modelling is just one tool used in preparation for spill response.”
In the event of a spill, spotter planes would be used to determine where the oil had reached.
Oil Spill Response had not provided comment at the time of writing. BMT Argoss said it was aware of the concern over long duration blowouts and added: "An upgrade has been developed and is currently undergoing testing. We aim to release it as soon as possible in the New Year."
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