Oklahoma City-based Western Natural Resources LLC is teaming up with global investor KKR to acquire producing and undeveloped oil and gas assets in the Williston Basin.

Financial details of the partnership were not disclosed. KKR made the investment via its Energy Real Assets strategy, which has invested $4 billion in 12 transactions since 2015 and manages a portfolio of oil and gas assets in numerous unconventional and conventional resource areas across the United States. The Energy Real Assets strategy prioritizes generating free cash flow and asset level returns in the upstream sector.

"We are excited to partner with KKR and bring what we feel is a differentiated view and business model to the basin to build a premier asset base focused on delivering strong risk-adjusted returns,” Western CEO Heath Mireles said.

Mireles is the former COO of Oklahoma City-based Flywheel Energy LLC. He also worked for Continental Resources Inc. for almost seven years and had served as vice president of resource development. In addition, he previously worked for BP plc for about four years.

"The Williston continues to be a core area of focus for us as we see a significant opportunity to acquire high quality producing assets with attractive long-term value creation opportunities to be delivered through superior technical and operational execution,” said KKR’s Ben Conner, director on the Energy Real Assets team.

“We have known Heath and members of his team for years and believe our partnership is well positioned to acquire and manage assets in the Williston for the long run."