A Mexican unit of Ensco International Inc. (ESV) won two out of four Mexican offshore drilling rig contracts during a recent bidding round held by state-run Petroleos Mexicanos, a company struggling to reverse plummeting oil production.

Drillers are keen to expand their presence in Mexico, one of the few oil producers expected to increase spending this year despite the 70% drop in oil prices from peaks last summer.

Ensco bid a combined $258 million to supply the two 250-foot independent leg cantilever jackup rigs, according to Pemex. Industrial de Servicios Outsourcing and First Drill Limited won another contract for a 250-foot jackup with a $110 million bid, and Blackstone Gerencia and Rowandrill won a 350-foot jackup contract with a $125 million bid.

The rigs will be deployed in the shallow waters of the Gulf of Mexico during the second and third quarters of this year, where Pemex produces around 80% of its oil.

-By Peter Millard, Dow Jones Newswires; 5255-5001-5724; peter.millard@dowjones.com