Abstract: BY-HF1 is the first horizontal well with long horizontal section of continental shale oil in Sinopec.Based on reservoir characteristics,wellbore structure and section characteristics of borehole trajectory of BY-HF1 well,the drilling difficulties have been analyzed,such as wall sloughing,long horizontal section,drag,big torque,high consumption in circulation and big difficulties in borehole trajectory.Therefore,corresponding measures have been taken.Rotary steering technology and oil-based drilling fluid system have been applied,which guaranteed the successful drilling and greatly enhanced the rate of penetration.The actual horizontal section of BY-HF1 is 1044 m,with smooth borehole trajectory,the average hole enlargement ratio of 3% and reservoir encountering rate of 100%,the requirements of engineering design have been reached.