WOOD Group has expanded its reach in the United States shale oil market with the acquisition of Texas based maintenance and fabrication business Duval Lease Services.

The value of the deal was not disclosed but Duval, founded in 1982, reported $32 million of sales in 2011 and had gross assets of $14m.

It operates in the onshore oil and gas market including the Eagle Ford shale region in the south of Texas which is rich in oil and natural gas formations.

There are estimated to be around 250 rigs operating in the area along the border with Mexico.

The company will be rebranded as Wood Group Duval and operate in the Wood Group PSN division adding to the support services operations in the US.

The existing management and 300 staff at Duval area all transferring over as part of the transaction.

Derek Blackwood, president for Americas at Wood Group PSN, said: ''The acquisition of Duval provides us with a robust platform for growth in the key Eagle Ford shale region and increases our overall exposure to the US onshore unconventional oil and gas markets."

Rene Casas, president of Wood Group Duval, said ''We are pleased to be joining Wood Group. Duval has achieved strong growth over recent years, and we anticipate the strong shale market, momentum in our business and the support of Wood Group will enable continued growth.''

Wood Group employs around 41,000 people based in more than 50 locations.