Hilcorp Energy Co, a closely held U.S. independent exploration and production company, on Dec. 18 said it had formed a partnership with private equity firm Carlyle Group LP to acquire and develop North American oil and gas properties.

Carlyle's Energy Mezzanine Opportunities Fund, LP and Carlyle Energy Mezzanine Opportunities Fund II, LP have agreed to invest up to $1.24 billion in the newly formed partnership called Hilcorp Energy Development LP.

Oil and gas companies are increasingly looking to private equity firms as low commodity prices sap cash flow and access to capital markets is squeezed. U.S. crude oil prices are hovering around seven-year lows amid a global supply glut.

On Dec. 18, Moody's said it was reviewing 29 oil and gas companies for downgrade, citing weak oil and gas prices. Hilcorp was on the rating agency's list.

Houston-based Hilcorp, founded by Jeffrey Hildebrand in 1989, has operations in the Gulf Coast of Texas and Louisiana, the U.S. Northeast and Alaska.