In a corner of the Australian Outback, a drilling crew will soon try tapping shale rocks that could hold more than three times the world's annual consumption of natural gas.

Origin Energy Ltd. plans to drill two wells later this year in the Northern Territory's Beetaloo Basin, after the local government ended a three-year ban on fracking — the practice of extracting oil and gas from layers of shale rock deep underground. With an estimated 500 trillion cubic feet (14 trillion cubic meters) of gas, Beetaloo has been compared to famed U.S. shale regions such as Marcellus and Barnett.

But its isolated location, lack of infrastructure and the likelihood of tough environmental opposition make Beetaloo a highly speculative investment.