A mixture of gas and condensate oil has been leaking from the West Atlas drilling rig in the Timor Sea since Friday morning.
A drilling rig to be brought from Singapore to help stop an oil and gas spill in the Timor Sea has been delayed.
PTTEP Australasia plans to bring the West Triton mobile offshore drilling rig to its Montara well head platform, where it will drill a relief well to stop a flow of oil, gas and condensate that started leaking off Western Australia's Kimberley coast last Friday.
The West Triton rig's has been delayed by difficulties in preparing to leave its berth in Singapore, the Thai-based energy company said on Thursday.
The cause of the leak is not known.
PTTEP said this week the leak was unlikely to have been triggered by project development activities, but it had probably started on the sea floor under the West Atlas drilling rig.
In addition to drilling a relief well, PTTEP on Thursday said it was deploying a dynamically positioned (DP) vessel to deluge the Montara well head platform and the West Atlas drilling rig to lessen the threat of fire, a company spokesman said.
The vessel was expected to be on site within four days following a safety evaluation.
"A second DP vessel is being mobilised to Darwin to be fitted out with more deluge equipment," PTTEP said.
"Alternatives to control the well flow are also continuing to be investigated by PTTEP with an emphasis on safety and technical feasibility."
The Australian Marine Oil Spill Centre has sprayed dispersants on the spill this week.
PTTEP on Thursday said the slick was in a "similar pattern as previous days, continuing in a northeasterly direction away from the mainland".
The Montara development is due to come online later this year.
AAP
