Greens and environmentalists are calling new ‘Deepwater Horizon’ after the release of BP’s oil spill modelling produced to evaluate effects of an oil spill in its proposed Great Australian Bight drilling program.

BP on Thursday released the worst-case oil spill scenario for Stromlo-1 well located within the project, located some 600 kilometers west of Port Lincoln and 400 kilometers southwest of Ceduna, in a water depth of approximately 2250 meters. The release came a day before the offshore safety regulator NOPSEMA, said it would need more time to evaluate BP’s GAB exploration drilling environment plan. BP’s plan needs to demonstrate that risks are ‘As low as reasonably practicable’ and ‘acceptable’.

A loss of well control event at Stromlo-1 prospect, to be drilled with the Ocean Greathwhite drilling rig, is characterised at the outset as a continual flow of oil from the well, rising through the water column with some lateral spreading and movement influenced by sub-sea currents, with a majority of oil droplets rising to coalesce at the sea surface, BP said in its assessment.

In BP’s scenario the oil would undergo weathering, a series of physical and chemical changes, involving principally evaporation, spreading out, dissolution, emulsification, biodegradation and breaking up into patches under the action of currents and wind. The oil would continue to move on the water surface until eventually, some amounts reach discrete parts of the shore along a wide stretch of the southern Australian coastline.

Oil spill could travel over 2.600 kilometers

When tracked to the low exposure (rainbow to metallic sheen) the maximum distance travelled by a spill from Stromlo-1 was approximately 2,650 km in an easterly direction for all seasons. When tracked to the moderate exposure (metallic sheen) the maximum distance travelled ranged from approximately 2,330 km – 2,630 km in an easterly direction (all seasons).

Regardless of the starting season, BP’s models showed there was a 100% predicted probability of shoreline contact at the low (10 g/m2 or film/stain), moderate (100 g/m2 or coat) and high (1,000 g/m2 or cover) thresholds.

The minimum time before shoreline loading at the low threshold was 9.2 days based on spills starting in winter compared to 18.7 days in summer. Models show the highest maximum volume of crude ashore occurred for a spill starting in winter and the greatest average volume of crude ashore resulted from spills commencing in transitional months.

Below is BP’s model for the projected shoreline contact depending on the season.

BP’s assessment show that regardless of the starting season, there was a 100% predicted probability of shoreline contact at the low (10 g/m2 or film/stain), moderate (100 g/m2 or coat) and high (1,000 g/m2 or cover) oil spill thresholds.

For spills beginning during summer the shorelines between Elliston to Coffin Bay (low: 97%, moderate 96% and high 89%) and Kangaroo Island (low 95%, moderate 95% and high 93%) recorded the greatest probability of contact. The minimum time before low shoreline loading was 19 days between Elliston to Coffin Bay.

For spills starting during transitional months, a 100% probability of low and moderate shoreline loading were predicted for: Elliston to Coffin Bay; Kangaroo Island; Streaky Bay; Port Lincoln; York Peninsula; Victor Harbour; Robe and Beachport; and Discovery Bay and Cape Otway. The minimum time before shoreline contact at the low threshold was predicted for the coastline between Elliston to Coffin Bay (17 days).

Winter starting spills resulted in the greatest probabilities of shoreline contact to Elliston to Coffin Bay (low: 100%, moderate 100% and high 89%), Kangaroo Island (low 94%, moderate 94% and high 84%), Great Australian Bight Marine National Park (low: 97%, moderate 97% and high 79%) and Port Lincoln (low: 98%, moderate 98% and high 28%). The minimum time for low shoreline contact for Elliston to Coffin Bay was 9 days.

Worth noting, BP’s worse credible discharge scenario excluded any measures designed to prevent this from happening.

“The modelling assumes that no attempts to control, contain, disperse or recover an oil spill are attempted. The fact that all of these measures would be employed in an actual spill event is not considered in this report,” BP said.

New Deepwater Horizon?

Greenpeace Australia said that the decision by Australia’s oil regulator, NOPSEMA, to delay a decision on BP’s Great Australian Bight oil exploration plans “shows the inherent dangers of a doomed project.”

‘To give BP the go-ahead with oil exploration would put Australia on the same dangerous path they took to the Gulf of Mexico disaster in 2010,’ said Greenpeace Australia Pacific’s Oceans campaigner, Nathaniel Pelle.

‘The latest spill and response models, released only days before a decision was originally due, prove BP’s Bight ambitions are an even bigger gamble than previously thought. Oil from an uncontrolled spill could reach the shoreline in every state except Queensland, at a terrible price to local people and the Bight’s unique and precious wildlife.

‘The maths is frightening. According to BP itself, within 20 days of a leak, Adelaide, Kangaroo Island and Port Lincoln could be doused in toxic oil and chemicals. BP says it could take 35 days to cap a leaky well off the Great Australian Bight. In the case of the Deepwater Horizon, it took 87.

‘The National Offshore Petroleum Safety and Environmental Management Authority (NOPSEMA) should reject BP’s plans once and for all before they progress any further,’ said Pelle.

Greens against drilling

The Australian Greens agree with Greenpeace. The party has said that BP’s plans to drill for oil in the Great Australian Bight should be rejected.

“Here we have it, straight from BP themselves,” South Australian Greens Senator, Sarah Hanson-Young said. “The environmental and economic impact of a spill on the marine life, fisheries and tourism industry of South Australia would be absolutely devastating.

BP’s model shows that in case of the spill, a number of species could to have a high probability of contact with surface hydrocarbons, including sperm whale, pygmy blue whale, sea lion, fairy tern, Pacific gull, short tailed shearwater and white-faced storm-petrel.

Hanson-Young added: “BP’s attempts to drill for oil in the Great Australian Bight should not be allowed to go ahead. It’s no wonder that this process has been so secretive from the get go, with BP sitting on devastating modelling like this. The entire SA coast, Victoria, WA, Tasmania and NSW are all in the firing line if BP have a Gulf of Mexico-style disaster in the Great Australian Bight. NOPSEMA cannot, in good conscience, allow this project to go ahead.”

The full BP oil spill modelling document can be found HERE (PDF).

Source: www.offshoreenergytoday.com