Blackstone Group LP is close to inking a billion-dollar deal for Royal Dutch Shell PLC’s half of 350,000 acres leased in north Louisiana’s Haynesville Shale, according to The Wall Street Journal.

Shell is part of a joint venture in the natural gas formation. The deal would be the latest in which a private equity firm bought oil and gas reserves. Earlier this year, Apollo Global Management LLC and Houston-based Halcón Resources Corp. formed a joint venture to develop the energy company’s 300,000-plus acres in the Tuscaloosa Marine Shale, an oil formation that covers Louisiana’s midsection and extents into Mississippi.

Apollo could invest as much as $400 million in the venture. Apollo also announced it would buy Encana Corp.’s natural gas leases in Alberta, Canada, in a $1.8 billion deal.