Jetting-Based Conductor Running Technology Used in Ultra-Deep Water Well of Lingshui Block in the Western South China Sea

The sea area of Lingshui Block in Western South China Sea is rough with average water depth of 1710.00 m. In this paper, jet drilling technology was used to run in conductors in order to ensure the stability of underwater wellheads and improve running efficiency of conductors. First, the load capacity curve of conductors was plotted by analyzing the soil samples taken from shallow sea beds in Lingshui Block. Second, the safe driving depth of conductors in this block was determined by analyzing the load on conductors. Finally, bit stick-out, bit diameter, WOB and hydraulic parameters were optimized by analyzing comprehensively the characteristics of jet drilling technologies and BHA (bottom hole assembly) used for ultra-deep water environments, and then the driving depth of conductors was determined. The jetting-based conductor running technology was applied on 5 wells in the Lingshui Block. Results showed that wellheads in this block were of good stability. The conductors were then run in holes successfully without deviation or subsidence. The successful application of jetting-based conductor running technology of Lingshui ultra-deep water block provides the technical inference for the drilling of similar ultra-deep water wells in the future.