Petrobras and the Nigerian Petroleum Corporation signed an agreement to explore deepwater block OPL324 offshore Nigeria. Petrobas would serve as operator under the 30-year contract and hold a 75 percent stake in the block. The agreement heralds Petrobras' first venture as an operator in Nigeria. Last month Petrobras acquired a 15 percent stake in block OPL250 which is operated by ChevronTexaco. Petrobras has inked a deal for a 30-year contract on block OPL324 offshore Nigeria. The company would have a 75% interest in the block and serve as operator.