HOUSTON (Bloomberg) ? Nabors Industries, Ltd., the world?s largest onshore oil and natural-gas driller, said third-quarter profit surged 64 percent as escalating exploration boosted demand for rigs.

Net income rose to a record $292.8 million, or $1.02 a share, from $178.9 million, or 55 cents, in the same period a year earlier, the company, based in Bermuda, and run from offices in Houston, said in a statement. Revenue increased 40 percent to $1.29 billion.

Rig companies are reaping windfall profits as oil and gas producers step up the quest for new reserves to capitalise on high prices. Drilling activity across North America this year surged to the highest level since 1985, according to date from oilfield services provider Baker Hughes Inc.

Nabors? per-share profit was 3 cents higher than the average estimate from 25 analysts in a Thomson Financial survey.

The earnings report was released after the close of regular US trading. Shares of Nabors rose 72 cents, or 2.4 percent, to $31.35 yesterday on the New York Stock Exchange.

Nabors? Chief Executive Officer Gene Isenberg, 76, and other drillers are charging higher rates as oil and gas producers expand exploration in Canada, the US Rocky Mountains and other regions with rich deposits.

While there is ?potential for softening? in North American gas markets, ?we still expect to see overall growth in these markets and larger growth in our other markets,? Isenberg said in today?s statement. ?We remain decidedly bullish.?