BHP Billiton Ltd. is mulling expansion in shale gas beyond the shores of the US, where it recently closed its $12.1 billion acquisition of Petrohawk Energy Corp.

"The shale gas is likely to play a big role in the world's energy scenario in near future and it's part of our medium to long-term strategy to participate in the process in other areas of the world too," said company CEO Marius Kloppers on Thursday.

"The Petrohawk (acquisition) is another tool in our aim to have many tools in the tool kit in terms of unconventional gas, and we like to build on that,” Kloppers said.

The Petrohawk transaction and the $4.75 billion purchase of Chesapeake’s Fayetteville shale assets provided BHP, marked the first forays into shale gas, by the seventh-biggest independent oil and gas company in the world.