Job fairs are stocked with people hungry for better opportunities, but inside the MCM Grande Hotel in Odessa, Texas, oil services giant Halliburton is the one doing the wooing.

“We need to hire you is our message,” said Chris Redman, a field services manager with Summit ESP, which Halliburton acquired last year.

More than 500 men and women flocked to the hotel in Odessa, Texas, on a Thursday last month to be courted by Halliburton, which needs people to handle everything from oilfield technicians to truck drivers, as oil production booms and qualified workers become more scarce.

The U.S. unemployment rate is 3.9 percent, just off an 18-year low, but job growth has slowed more recently – notably because companies are having trouble finding people.