南海西部深水钻井实践

南海西部海域W区块的深水钻井作业中,低温高压和狭窄的安全密度窗口给钻井工程带来了较大的困难,容易引起井漏、溢流、环空带压、生成水合物等问题,且附近海域经常出现由内波流引起的突发性强流。针对这些问题,结合W区块的钻井地质特征,开展了深水井井身结构优化技术、随钻扩眼技术、深水井钻井液防水合物及防漏堵漏技术、环空压力预测与管理技术、内波流应对技术等方面的研究,解决了深水钻井容易发生的井漏与溢流并存、水合物堵塞管线、环空压力高和内波流损坏水下设备等问题,并成功发现了大型深水气田。

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.