HOUSTON — Oilfield services firm Schlumberger agreed to sell its North American shale fracking business to rival Liberty Oilfield Services, unloading a unit that underperformed during the shale bust.

Schlumberger will take a 37-percent stake in Liberty, and the projected revenue would make Denver-based Liberty the third-largest U.S. oilfield services firm by sales.

Liberty will pick up advanced hydraulic equipment and two West Texas frack sand mines, Liberty CEO Chris Wright said.

For more information, visit www.slb.com or www.libertyfrac.com.