Australian oil and gas firm Woodside has signed a sales and purchase agreement with Shell Development Australia to acquire its North West Shelf oil interests for $398.5 million.

Shell’s North West Shelf oil assets include its share in the Cossack, Wanaea, Lambert and Hermes oil fields, including the Cossack Pioneer production facility, the Egret oil discovery and remaining active oil exploration portfolio within a tieback distance to the Cossack Pioneer.

The sale will increase Woodside’s participating interest in the Cossack, Wanaea, Lambert and Hermes fields to 33.33%. The company’s interests in the Egret oil discovery area and remaining active oil exploration portfolio within a tieback distance to the Cossack Pioneer will increase to 50%.

The agreement covers estimated proved and probable reserves of 21.3 million barrels of oil equivalent, and an additional 9.3 million barrels of contingent resources. The purchase price is equivalent to $18.71 per barrel of oil equivalent for proved and probable reserves.

Don Voelte, Woodside’s CEO, said: The North West Shelf has laid a sound business platform for Woodside over two decades and we are very pleased that this transaction will further consolidate our position in the North West Shelf Ventures.