Shale gas wildcatter Aubrey McClendon is buying up large swaths of Australian land to explore for shale oil and gas months after Chevron and ConocoPhillips abandoned unsuccessful drilling projects there.

McClendon's 2-year-old company, American Energy Partners, has struck four separate deals to buy 55 million acres in the McArthur Basin in Australia's Northern Territory and is working to secure another 10 million acres there, according to an internal company memo obtained by the Houston Chronicle.

The combined acreage is roughly 1.5 times the size of Oklahoma, McClendon says in the memo, and about 10 times bigger than the productive portion of the Marcellus and Utica shale plays in Pennsylvania, West Virginia and Ohio. McClendon didn't disclose a price tag for the land in the memo.

"The Australian oil and gas community seems very excited about us bringing our world-class resource development capabilities to a country that is resource rich, but to date has not experienced successful large-scale unconventional oil and natural gas resource development," McClendon said.

The sellers include a private company and Australian oil and gas producers Armour Energy and Empire Energy Group. The acreage spans five sub-plays within the McArthur - the Beetaloo, Carpentaria, Glyde, North McArthur and South Nicholson basins.

McClendon said he expects to close the deals later this year or in early 2016, and that the company probably will begin seismic imaging and drilling next year.

Several U.S. shale explorers including Harold Hamm, CEO of Continental Resources, and Scott Sheffield, CEO of Pioneer Natural Resources, have said they're not willing to venture overseas for untapped shale oil and gas because the best shale rock is rare and in most countries it's too expensive to drill.

McClendon, who was ousted as CEO of Chesapeake Energy Corp. in 2013 amid shareholder pressure, has spent hundreds of millions in the past two years building a second oil and gas empire by buying up land in West Texas and in Ohio's Utica Shale.

And last week, McClendon announced that American Energy has struck a deal with Mexico City's EIM Capital to drill into shale rock in Mexico.