The Carlyle Group Inc. agreed this week to fund one of Diamondback Energy Inc.’s Permian Basin developments in West Texas.

The joint venture (JV) agreement would help defray costs in the San Pedro area of Pecos County, a leasehold within the southern Delaware sub-basin.

Carlyle Energy Mezzanine Opportunities Fund II LP would pay up to 85% for development over a five-year period and allow Diamondback “to bring forward present value on the southeastern portion of our Pecos County acreage, with added benefit to our minerals and midstream businesses,” Diamondback CEO Travis Stice said.

No financial details were disclosed.

Once certain “performance hurdles” are achieved, most of Carlyle’s working interests would revert to Diamondback. The hurdles were not defined.

“We are incredibly excited to start this partnership with Diamondback, which has demonstrated year-after-year excellence in developing the Permian Basin,” said Carlyle Energy’s Vince Hahn, managing director on the Mezzanine Opportunities team.

Midland, TX-based Diamondback, on track to become a large-cap exploration company, has been on a merger tear in the Permian for the past couple of years.

Last month, it made a blockbuster deal to take over Permian competitor Energen Corp. for an estimated $9.2 billion. The Energen tie-up came only days after Diamondback struck a deal to pay an estimated $1.2 billion for Permian acreage in the Midland sub-basin from Ajax Resources LLC. Two years ago, Diamondback bought Brigham Resources affiliates for an estimated $2.43 billion, adding a substantial leasehold that included land in Pecos County, where the Carlyle JV is to be focused.

Once the Energen and Ajax transactions are completed, Diamondback would hold an estimated 390,000 net acres across the Midland and Delaware, an 85% increase from the end of June when it held 211,000 net acres.

Carlyle Energy provides growth and refinancing capital to the energy sector through two funds, which at the end of June had combined assets of about $4 billion.

UBS Investment Bank served as Diamondback’s financial adviser and Akin Gump served as counsel; Vinson & Elkins was counsel to Carlyle.