Abstract: n Branch, CNOOC， Shenzhen 257237， Guangzhou China) Abstract Liuhua 11-1 jacket is the deepest deepwater jacket in Asia at present. Compared with shallow water jacket， Liuhua 11-1 jacket has the characteristics of high design risk， long construction cycle， high steel production technology and difficulty in welding. This paper will study the production process of S420 super-strength steel， jacket design risk， construction risk， dynamic performance， welding quality control measures and other aspects， so as to provide reference for similar deepwater jacket project management and control in the future.

Key words: Liuhua 11-1 jacket, super-strength steel, risk management and control, technology for heating processing, welding quality control