Piedra Energy and Rock River Minerals said Sept. 27 they closed their fourth capital commitment with Houston-based private-equity firm EnCap Investments LP.

With this closing, the Piedra companies bring their aggregate outstanding commitments to $592 million earmarked for deployment in the Permian Basin, according to the company press release.

“We have enjoyed our relationship with EnCap over the last 11 years,” said Piedra Co-Founder Chip Smith in a statement. “EnCap and Piedra enjoy a common vision for growth and success in the Midland and Delaware Basins.”

The Piedra companies are Midland-based and privately held. Piedra Energy is actively drilling horizontally in multiple benches in the Spraberry/Wolfcamp Trend of the northern Midland Basin. Rock River Minerals will continue its focus on aggressively expanding its mineral and royalty footprint in both the Midland and Delaware Basins.