The proposal is to drill an exploratory oil well at a site 6 km offshore from the mouth of the Ashburton River and 20 km west of Onslow. Drilling is expected to begin in December 1989 and will take about three weeks to complete.

The proposed site lies within a Special Protection Locality in water about 10 m deep.

The Ashburton River delta is regarded as being environmentally sensitive because of the presence of mangrove stands. As well, islands, fringing corals, and seagrass meadows nearby have high conservation values.

Onslow's interests centre on the tourist, fishing and petroleum industries, and the drill site lies within locally important prawn fishery areas.