* Futures up: Dow 89 pts, S&P 6.5 pts, Nasdaq 22.25 pts
By Amy Caren Daniel
Aug 7 (Reuters) - U.S. stock index futures rose on Tuesday as strong corporate earnings lifted sentiment and higher oil prices helped energy shares.
Oil prices rose on expectations of tighter global supplies due to revived U.S. sanctions against major crude exporter Iran.
Schlumberger gained 1.2 percent, Exxon 0.8 percent and Chevron 0.2 percent in premarket trading.
"The indices are poised to open on a higher note as corporate earnings, higher oil prices and less focus on the trade rhetoric lift investor spirits," Peter Cardillo, chief market economist at First Standard Financial in New York, wrote in a note.
Technology shares were among the most traded, while a rebound in the Shanghai stock market helped drive gains in U.S.-listed shares of Chinese companies.
E-commerce giant Alibaba gained 1.1 percent after sources told Reuters that it planned to merge its food delivery units and raise funds for the combined business. JD.com was up 0.8 percent.
The S&P 500 edged closer to a record it hit on Jan. 26 on Monday, closing within a percentage point of the all-time high for the first time since the current correction began.
The CBOE Volatility Index, the most widely followed barometer of expected near-term gyrations for the S&P 500, dropped to 10.52 points, level not seen since the early February selloff.
Among the biggest premarket movers was Office Depot, whose shares rose 7.1 percent after its quarterly results topped analysts' estimates.
Walt Disney rose 0.7 percent ahead of its results after market close.
Of the 413 S&P 500 companies that have reported earnings so far, 79.2 percent have topped estimates. If the beat rate holds, it will be the highest on record, dating back to the first quarter of 1994, according to Thomson Reuters I/B/E/S.
At 7:20 a.m. ET, Dow e-minis were up 89 points, or 0.35 percent. S&P 500 e-minis were up 6.5 points, or 0.23 percent and Nasdaq 100 e-minis were up 22.25 points, or 0.3 percent.
Marriott International fell 3.3 percent in low volumes after the world's largest hotel chain signaled weakness in revenue per available room (revPAR) in North America for the third quarter.
Express Scripts fell 1.9 percent after billionaire investor Carl Icahn urged Cigna's shareholders to vote against the health insurer's $52 billion acquisition. (Reporting by Amy Caren Daniel in Bengaluru)