* Second-quarter revenue up 10 pct, beats expectations
* Raises share buyback program to $6 bln from $5 bln
* Sees risk from U.S. sanctions on Russia later this year
* Sees N. America margins of 20 pct in Q3 vs 18.2 pct in Q2
* Shares hit life-high (Updates link to graphic)
By Swetha Gopinath and Ashutosh Pandey
July 21 (Reuters) - Halliburton Co, North America's top oilfield services provider, said it would add fracking equipment and crew to take advantage of higher demand in the region, signaling an industry-wide recovery after a two-year slump.
Shares of the world's No.2 oilfield services provider rose 2 percent to a life-high of $72.20 after the company also raised its share repurchase program to $6 billion from $5 billion.
Halliburton, like global leader Schlumberger Ltd, said while there was no impact on business yet due to the U.S. sanctions against Russia, projects being tendered later this year could be impacted. The country contributes in the "low single digit" percentage to Halliburton's total revenue.
"As tensions potentially escalate and the risk of more sanctions sort of looms, that's what we believe puts some risk into the business in the back half of the year," Chief Executive David Lesar said on a post-earnings call.
Halliburton reported a 20 percent rise in second-quarter profit, meeting Wall Street's expectations, as drilling activity increased in North America.
Halliburton, which gets half its revenue from North America, said it expects margins in the region to touch 20 percent in the current quarter, up from 18.2 percent in the quarter ended June 30.
The company's margin in the region was higher than Baker Hughes Inc's 12 percent and Schlumberger's 18 percent.
Halliburton said it would "immediately" speed up additions to its crew and hydraulic fracturing fleet as capacity tightened in North America.
"I think it is a kind of vote of confidence that demand is on its way back," said S&P Capital IQ analyst Stewart Glickman.
Prices for hydraulic fracturing, where water, chemicals and sand are blasted into wells to extract oil and gas, have been depressed due to excess equipment and a drop in natural gas drilling, brought on by low prices of the fuel.
However, a recent rise in natural gas prices has led to increased drilling, helping boost revenue at Halliburton, Schlumberger and Baker Hughes.
Halliburton's revenue from North America rose sequentially to 11 percent in the second quarter - stronger than a 9 percent rise in the eastern hemisphere, where it had been making a strong push to combat the weakness in North America.
The weakest region was Latin America, where revenue rose just 4 percent, dragged down by reduced activity, a delayed order and costs related to new projects in Mexico.
Margins in the region are expected to improve in the second half, with full-year margins in line with those a year earlier.
The company's revenue rose 10 percent to $8.05 billion, beating the average analyst estimate of $7.88 billion.
Halliburton also said it would move the role of president to Chief Operating Officer Jeff Miller from Chief Executive David Lesar, effective Aug. 1. (Editing by Maju Samuel and Savio D'Souza)