Weeks after the firm said it might work on shale projects in the UK in the future, Wood Group said it is generating revenues worth $500 million (£320m) annually from work on such developments in the US.
The company has 2500 personnel providing engineering, operations and maintenance services to US shale fields.
Wood Group's chief executive Bob Keiller said: "Shale production is significantly changing the global energy market. Wood Group has the knowledge and experience to support our customers as they increase their focus on shale regions worldwide."
Asked last month if the group would be interested in supporting firms that used fracking in the UK, Mr Keiller said: "I think people have got concerns that need to be aired and debated, but ultimately if it was to go ahead and that was the settled view of society that it should then we would like to think the expertise that we've got ... could be used to service that market."
Wood Group said it is recruiting more than 100 people to work in its office in Woking, Surrey, after winning a string of North Sea engineering contracts.