Oilfield services firm Wood Group is buying rival PSN for $955m (£607m) as it beefs up its global reach.PSN will be merged with Wood's production facilities business, creating Wood Group PSN. It will be run by PSN's chief executive Bob Keiller who'll also join the board.The firm was formed in May 2006 when Keiller led a $280m (£178m) management buyout from America's Halliburton, making it one of the top ten largest private Scottish companies. Keiller, who owns 10% of the company, stands to make about £60m from today's deal."The acquisition will be significantly earnings and cash flow enhancing immediately following completion," Aberdeen-based Wood said Monday.The enlarged group will have revenues of over $6bn compared with $4.9bn in 2009. Completion is expected in the second quarter of 2011. In a separate trading update, the UK mid-cap reported continued progress at most of its key divisions and thinks the overall performance for 2010 is likely to be slightly ahead of expectations. "Looking further ahead, we believe the fundamentals for oil & gas services and gas fired power generation remain strong and that we are well positioned to deliver good medium term growth," it added.