Schlumberger is exploring a possible sale of Thomas Tools — a Louisiana-based oilfield tool rental firm it took over in the 2010 acquisition of Smith International. Via Reuters, the sale could be valued at more than $600 million. Thomas Tools has annual EBITDA of approximately $80 million. Investment firm PPHB is advising Schlumberger on the process. The Houston-based oilfield services giant has reportedly garnered interest in Thomas Tools from private equity firms, but neither Schlumberger nor PPHB has commented on a possible sale.