Chevron said Wednesday it is investing $300 million in an Indian facility that is expected to become the world's largest refinery complex. The U.S. oil giant said it is buying 5 percent of Reliance Petroleum Ltd., a company set up by Indian conglomerate Reliance Industries to own and operate the export refinery being built at Jamnagar on India's northwest coast. Chevron said it can increase its stake in Reliance Petroleum to 29 percent as the new Jamnagar refinery begins operations in December 2008. Reliance operates a 650,000-barrel-per-day refinery in Jamnagar. The new refinery of similar capacity is being built alongside, and combined the two would make the largest refinery complex in the world, Chevron said. "We are very pleased to have forged this relationship with Reliance, one of India's leading companies, which has excelled in the execution of world-class projects," Chevron chief executive Dave O'Reilly said.