Abstract: The DF29-1-6 is a high temperature and high pressure exploratory well drilled by KANTAN Ⅲ which is a semi-submersible drilling platform. This well faced two significant challenges during the drilling process, one is high temperature and high pressure, which has great influence on drilling fluid stability. The other is the well control problem because the safety window is very narrow and the formation pressure is close to the fracture pressure. During drilling 212.7 mm(8-3/8") well section which is characterized by high temperature and pressure, lots of measures have been taken, such as meticulous management and operation, optimizing BHA, monitoring closely the drilling parameters, especially the temperature of the drilling fluid back to the wellhead, maintaining good rhe-ology and stability of the drilling fluid under high temperature and high pressure conditions, cementing plug well at the stage of well abandonment and so on, to finish the well drilling safely and excellently. Through this well, KANTAN Ⅲ has obtained rich experiences in the field operation, which can be used in the domestic offshore high temperature and high pressure well drilling.