Drilling practices of deepwater well in West of South China Sea

During the deepwater drilling operation of W block in the sea areas in the west of South China Sea, the low-temperature, high-pressure and narrow safety density window has brought about great difficulties to the drilling engineering, and may easily lead to lost circulation, overflow, annular pressure, hydrate generation and other problems, and the sudden strong current arising from the internal wave current frequently occurs in the nearby sea areas. Based on these problems and drilling geological characteristics in W block, the researches on optimization technology of wellbore structure of deepwater well, technology of reaming while drilling, hydrate prevention and leakage-proof & plugging technology of drilling fluid of deepwater well, annular pressure prediction and management technology, coping technology of internal wave current and the like have been conducted, lost circulation & overflow coexistence, pipeline blocking by hydrate, high annular pressure, damage of underwater equipment by internal wave current and other problems which may easily occur in the deepwater drilling have been solved, and a large deepwater gas field has been successfully discovered. The successful drilling experience of self-support deepwater well in the west of South China Sea may provide reference to the deepwater drilling technicians.