Executives from CNOOC are headed to the US this week to discuss their $18.5 billion bid with Unocal that trumped Chevron's $16.4 billion cash and stock bid, a source familiar with matter told Reuters.



Chevron is pushing for an August vote on its offer, which has already been accepted by Unocal.



"We had planned for and want to participate in a (government) review of the transaction as soon as possible," said CNOOC chairman and chief executive officer Fu Chengyu.



"We