SYDNEY, April 29 Reuters BP has agreed to buy rival giant Shell39;s 27 stake in the Browse joint venture, expanding its holding in Australia39;s largest untapped gas resource in a move that could improve the development prospects for the longstalled project.

The Browse project, estimated to cost 20.5 billion, has been stuck on the drawing board for years but is now being considered as a replacement for ageing gas fields to supply the North West Shelf LNG liquefied natural gas plant.

Development of Browse would extend the life of the North West Shelf LNG plant for decades, helping to meet demand for LNG from Australia39;s biggest trading partners, including China, Japan and South Korea, even as they turn to cleaner energy.

Shell Australia said in a statement on Saturday it had agreed to sell its stake in Browse as the asset is no longer a strategic fit in the context of Shell39;s global portfolio.

If the deal goes ahead, BP will increase its stake in Browse to 44, overtaking operator Woodside Energy Group39;s 30.3 stake. Woodside, BP and Shell are also all stakeholders in the North West Shelf LNG plant.

BP believes development of the Browse gas resources could make a significant contribution to energy security in Australia and to the Asia Pacific region, a BP spokesperson said.

BP39;s move comes after the major scaled back its climate targets in February with plans to produce more oil and gas for longer.

The company said it supported the concept of using carbon…