The North West Shelf well featured heavily in the news this week after the joint venture announced a potentially game-changing discovery.

Analysts said the oil discovery was potentially the largest in Australia over the past three decades and could host 60-90 million barrels of commercial oil reserves.

The well was completed at a depth of 4595m after encountering the Locker shale.

Quantitative analysis is yet to occur over the two 10m sands but preliminary indications from real-time logging data suggests that both sands are hydrocarbon bearing.

The estimated well cost came in under the previous guidance of approximately $6 million net to Carnarvon, which owns a 20% interest.