It is an oil producers worst nightmare; an uncontrolled oil spill. That is what happened on Friday, August 21st, at the West Atlas mobile offshore drilling unit. The blow-out occurred in one of the remotest locations possible in the Timor Sea around a depth of 3500 meters (two miles). Reportedly the oil spill began when a plug at a drilling hole released for unspecified reasons following a hydrogen sulfide leak. All 69 workers were evacuated from the rig that day. It is estimated the rig is leaking 470,000 liters of oil per day since the accident. The rig operator PTTEP Australasia, a unit of Thailand’s PTT Exploration and Production PCL, must drill a relief well to intersect the existing well to stop the flow of oil which isn’t going to be easy....It is an oil producers worst nightmare; an uncontrolled oil spill. That is what happened on Friday, August 21st, at the West Atlas mobile offshore drilling unit. The blow-out occurred in one of the remotest locations possible in the Timor Sea around a depth of 3500 meters (two miles). Reportedly the oil spill began when a plug at a drilling hole released for unspecified reasons following a hydrogen sulfide leak. All 69 workers were evacuated from the rig that day. It is estimated the rig is leaking 470,000 liters of oil per day since the accident. The rig operator PTTEP Australasia, a unit of Thailand’s PTT Exploration and Production PCL, must drill a relief well to intersect the existing well to stop the flow of oil which isn’t going to be easy.

The spill occurred at the Montara development, a project due to come on stream later this year. The West Atlas drilling unit is owned by Norway’s SeaDrill Ltd, but operated by PTTEP Australasia. The slick is located about 250 kilometers off the far north Kimberly coast and northwest of the Western Australia town of Truscott. Last estimates of the spill size were 25 nautical miles to the North and 70 nautical miles to the east of the rig and traveling in a north-easterly direction. The spill is not expected to reach shore.

Even in this remote location the environmental impact of the spill is a major worry. The giant slick area is part of an “ocean super highway” for migrating animals between the Indian and Pacific Oceans. There is a big concern for the air breathing marine life that could surface in the oil. “From a global scale this is one of the most important places on the planet for ocean wildlife,” said Gilly Llewelyn, WWF Australia’s director of conservation. Among the animals affected are three endangered species of turtles, plus sea snakes and possibly the pygmy blue whale which has been monitored there.

PTTEP Australasia’s chief executive, Anon Sirisaengtaksin, issued a statement that the company is focusing on eliminating the oil slick and stopping the well from leaking. They are working with authorities to “ensure that the work is done safely and with minimal environmental impact.” The West Triton rig, which will drill the relief well intended to plug the leak, is on schedule to reach the Monara field on September 8. The rig left Indonesia’s Batam Island, near Singapore on August 28.

The West Triton, a jack-up rig, was the most appropriate to drill the relief well and stop the flow of gas and oil safely and quickly. The idea was also backed by petroleum engineers from Geoscience Australia. It was estimated that it would take 20 days to bring the new offshore drilling rig by barge from Singapore, plus four weeks to drill the relief well. This means the oil flow will continue another month or more.

PTTEP Australasia also chartered a Boeing 747 to carry a high-capacity pump and deluge spray equipment for pumping sea water. It will be fitted to two vessels and will deliver 130,000 liters per minute of sea water to disperse condensate and reduce the fire risk. Tons of dispersant chemicals have been dumped by planes on the slick and most of the oil is breaking up naturally, but it will take weeks to clean up the spill.

To put it in perspective, if the West Atlas rig leaks 470,00 liters of oil a day from the onset of the blow-out through the expected duration of the rig repairs, the volume of crude oil escaping into the ocean may equal the amount released during the devastating 1989 Exxon Valdez oil spill in Alaska.