Halliburton Co , the world's second-largest oilfield services company, reported a forecast-topping 54 percent jump in profit on Monday as a U.S. onshore drilling boom showed no sign of cooling off.

High oil prices have led oil and gas producers to plunge billions of dollars into developing fields such as the Eagle Ford shale in Texas, creating a tighter market for equipment that allowed Halliburton to push through price rises.

The second-quarter results show Halliburton benefited from its leadership in the North American market in the pressure pumping technology that enables producers tap shale fields.

It was both top and bottom lines, and a significant component was pricing, said Roger Read, an analyst with Morgan Keegan & Co.

Halliburton said the North American boom was likely to last beyond this year, helped by the move away from natural gas drilling toward developments that benefit from high crude oil prices.

What we are seeing in North America, plus the continued international recovery, will lead to even a more favorable earnings picture as we go through 2011 and beyond, Chief Executive Dave Lesar told analysts on a conference call.

Second-quarter net profit climbed to $739 million, or 80 cents per share, from $480 million, or 53 cents per share, a year earlier.

Excluding one-time items, the company earned 81 cents per share, topping the 74 cents per share that analysts had on average forecast, according to Thomson Reuters I/B/E/S.

Second-quarter revenue rose 35 percent to $5.9 billion and came in above the average analyst forecast of $5.71 billion.

Margins would grow more slowly in the third quarter than in the second due to cost inflation and a slowdown in the recovery of Gulf of Mexico deepwater drilling as new permits become harder to come by, executives said.

The pace of permit issuance has slowed again and the fact that some of the initially permitted wells are nearing completion creates a risk that the Gulf recovery could slow or stall in the second half of 2011, Lesar said.

Second-quarter activity outside North America was soft, the company said. Seasonal pickups in the North Sea and Russia lifted revenue, but the Libya shutdown, delays in Iraqi projects, rising sub-Saharan Africa costs and sluggish markets in Britain and Algeria all cut into profits in those markets. Lesar said those factors shaved 4 percentage points off Eastern Hemisphere margins.

Halliburton shares rose 22 cents to $53.30 in early trading, even as a 1 percent drop in oil prices hurt the sector.

(Reporting by Matt Daily in New York and Braden Reddall in San Francisco; Editing by Derek Caney and Maureen Bavdek)

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