DARK clouds are gathering over China's Qinhuangdao 32-6 project in the Bohai Bay as Single Buoy Moorings gears up for a legal assault on Sofec for alleged breach of a design patent. The dispute centres on the $700 million to $800 million floater development located around 250 kilometres south-east of Beijing. Qinhuangdao 32-6 is China's second-largest offshore oilfield after Suizhong 36-1 with more than 1 billion barrels of heavy sweet oil in place.