Energy services firm Wood Group said it expects 2014 operating profits to be in line with expectations and higher than last year, but reported a mixed performance in its PSN division in the first half.In a trading update for the six months to June 30th, the company said that the Production Services unit of PSN has performed ahead of expectations, but Turbine Activities has disappointed.The company said that the financial performance in its turbine maintenance and repair business is "behind plan" due to a number of contract deferrals and slower activity in certain areas. An improvement is expected in the second half "although not to the level originally anticipated", it said.On a positive note, growth in Production Services was been driven by the Americas region, principally in US shale where it has seen "good organic growth". The North Sea region is also putting in a good performance.Elsewhere, Wood Group Engineering has traded in line with expectations. While market activity in upstream has been affected by clients' focus on capital efficiency, the subsea, onshore and downstream businesses have traded well.The company still expects full-year earnings before interest, tax, depreciation and amortisation to show growth on the $533m reported for 2013.BC