Completion operation practice of deep-water gas wells in the Eastern South China Sea

In a deep-water gas field in the eastern South China Sea, the sixth generation semi-submersible deep water drilling platforms West Hercules and HYSY981 were successfully applied for completion of nine wells, with average single-well operating cycle of 41.03 d. This paper describes the characteristics of deep-water completion technology and analyzes design principle of well completion string. Combining with the well conditions and characteristics of the environment, it also summarizes the difficulties and solutions in deep-water well completion operation. Finally, a set of perfect deep-well completion technology is formed, including material corrosion, hydrate prevention, annulus trap pressure management, production string design optimization, frac-packing, continuous wellbore cleaning, subsea tree installation and replacement, emergency response in complex condition, and fine operation. The flowing well test and function test before well production show that the well production and the performance of completion equipment meet the well production requirements. This technology could provide a good reference for completion design and operation in other deep-water oil and gas fields in the future.