A private equity firm that specializes in shale drilling fired 111 people at its Houston headquarters. : (Bloomberg) -- EnerVest Ltd., a private equity firm that specializes in shale drilling, fired 111 people at its Houston headquarters, citing “challenging times for the industry.” The job cuts were made “in an effort to right-size our company and ensure a successful future,” company spokeswoman Lindsey Welch said in an email on Monday. EnerVest sold its Eagle Ford Shale wells and drilling rights in 2018 for $2.4 billion in a transaction that created Magnolia Oil & Gas Corp.