Energy-focused private equity firm NGP Energy Capital Management LLC is evaluating a potential sale and other options for Oilfield Water Logistics LLC, or OWL, Bloomberg News reported, citing people familiar with the matter.

The sources told the news outlet that Dallas-based OWL could be valued at $600 million or more in a sale.

OWL owns infrastructure for gathering and disposing of water used for shale well fracking in the Permian Basin of Texas and New Mexico, and owns assets in the U.S. Midwest. NGP is backed by Carlyle Group LP.

Neither representatives for NGP nor OWL responded to requests for comment, according to Bloomberg.