(Reuters) - Energy services firm John Wood Group Plc (>> John Wood Group PLC) reported a 3.1 percent increase in full-year core earnings, helped by strength in its brownfield services unit.

Shares in the company rose as much as 9 percent on the London Stock Exchange and were the second largest gainers on the FTSE-250 midcap index <.FTMC>.

Wood Group, which counts BP Plc (>> BP plc) among its customers, said earnings before interest, taxation and amortisation (EBITA) in its Wood Group PSN unit rose 30 percent, helped by its U.S. shale oil business.

The company said its focus on production-related activity significantly weighted towards customer operating expenses would provide relative resilience in a more challenging market in 2015.

Wood Group said it would continue to look for acquisitions but that it would "apply tougher filters" due to lower oil prices.

The company, which saw opportunities to grow in the Middle East, Africa and Australasia, said it would benefit from the recent Swaggart acquisition in the United States where it expected a good longer-term market for its shale activities.

Wood Group, founded in 1912 as a ship repair and marine engineering firm, said full-year EBITA rose to $549.6 million (357.8 million pounds) from $533.0 million a year earlier.

Pretax profit for 2014 rose to $424.2 million from $412.3 million a year earlier. Revenue rose 7.8 percent to $7.62 billion.

Shares in the company were up 7.4 percent at 676.5 pence on the London Stock Exchange at 0911 GMT.

(Reporting By Mamidipudi Soumithri in Bengaluru; Editing by Gopakumar Warrier)

Stocks treated in this article : John Wood Group PLC, BP plc