Mandatory Credit: Photo by HAP/Quirky China News / Rex Features (2100965b) View of oil rig surrounded by frozen sea from an ice breaker ship Oil rig surrounded by frozen sea in Bohai Bay, Shandong Province, China - 26 Jan 2013 Due to the continuing low temperatures in northern China even a number of offshore oil rigs have found the water around them in Bohai Bay freeze. According to the management company for the oilfields the area of frozen sea is larger than it has been for the past 25 years. The company is having to use ice-breaking ships to travel between the shore and the rigs.