A $6.4 billion gas project being built by Chevron CVN.X in China is facing further delays due to disagreements with partner PetroChina ( 0857.HK ) over how to develop the technically tricky fields, three industry sources said. The Chuandongbei project, the U.S. firm’s largest investment in China, is now not expected to deliver first gas until the second half of 2014, nearly 7 years after the firms clinched a 30-year deal to produce 7.6 billion cubic meters of gas a year. The latest setback follows a series of delays for Chuandongbei, which Chevron has described as one of its larger capital projects for 2013. PetroChina initially expected first gas to be delivered in 2010, while its parent CNPC forecast just four months ago that production would start by end-2013. China, the world’s top energy user, but the fourth-largest consumer of gas, is racing to unlock supplies […]