Abstract: The Tahe oil field is a carbonate fractured-and——vuggy reservoir in Ordovician. Reservoir depth averages 5 300-5 720 m, with a maximum of 7 143 m. It has a strong heterogeneity, and drilling leakage rate reached 30% with a large leaking volume, about 560 m³ of drilling fluid for each single well. Open hole completion technology was applied to leaking wells. The traditional well completion technology has some shortcomings when grouping completion pipe column and changing for wellhead. We optimized wellhead controlling technology and the safe deployment of well completion pipe string, which fundamentally eliminated hidden troubles to ensure the safety of high-risk operations, controlled well safety, and saved operation cost.