The heterogeneity of the sand-shale interbeds in the lower part of the oilfield produced strong vibration of the downhole drilling string, leading to short life of PDC cutting teeth and easy hole deviation. At present, PDC drill bits are designed with 5 blades or 6 blades with 16mm cutting teeth to reduce the downhole tool vibration to ensure the life of the PDC bit, but the drill bit aggression is reduced and the mechanical drilling speed is lower. Based on the characteristics of lower formation in KKM Oilfield, a 4-blade 19mm composite PDC bit was selected. The drill bit provided high rock breaking efficiency and aggression capacity, which can greatly increase ROP. At the same time, through the bottom hole assembly dynamic analysis, the bisector + single stable single bending (0.5°) drilling tool combination was optimized. The application of three stabilizers can achieve strong vibration reduction effect, which can effectively improve the anti-deviation ability and reduce the downhole vibration with the small-angle downhole motor tool, and also with large-size PDC bit, the goal of drilling the lower section in one run was achieved. The ROP was increased by 115.35%.