Wellbore Trajectory Control Technologies for Ultra-Deep and High-Temperature Horizontal Wells in the Shunbei Oil & Gas Field

The failure rate of Measure While Drilling (MWD) instruments is high in the Shunbei Oil&Gas Field due to deep buried reservoir and high bottom-hole temperature and pressure. The MWD instruments are often not available in high temperature section of horizontal wells and the wellbore trajectory is difficult to control. In order to reduce the difficulty of wellbore trajectory control and improve the drilling efficiency of ultra-deep and high-temperature horizontal wells in the Shunbei Oil&Gas Field, this study integrated wellbore trajectory design and control technology. The wellbore trajectory was designed as multiple circular arcs with higher build-up rates in upper section and lower build-up rates in lower section to optimize the bottom hole assembly (BHA) and drilling parameters. A Positive Displacement Motor (PDM) with single bend and stabilizer was applied for compound drilling and controlling the wellbore trajectory when no MWD instrument was available in the lower high-temperature section. The research and field applications demonstrated that adopting the above compound drilling and optimizing BHA and drilling parameters according to the predicted well inclination variation rates, the inability to apply MWD for wellbore trajectory control can be solved. And in this way, the difficulties in wellbore trajectory control was lowered, and the drilling efficiency is highly improved.