The field covers 2,400 square kilometres (926 square miles) and is located in Iran's southwestern province of Khuzestan, Rouhani said in a speech aired on state TV
OPEC's Mohammad Barkindo said he was more optimistic about the market outlook for next year than he had been in October
The state-owned firm is the world's largest oil producer, pumping 10% of the world's supply, and the most profitable company with its half-year net profit rising 12% to $46.9 billion.
International benchmark Brent crude futures, were at $57.61 a barrel by 0009 GMT, up 23 cents, or 0.4%, from their previous settlement
So far, Caracas & Tehran have been adamant that Opec doesn't need to boost production this year, and have warned against succumbing to pressure from Washington