Abstract: The horizontal well,Nan 246-Ping 309,is located in Daqing Aonan Oilfield,with Putaohua Formation being its target.The stairs horizontal well has seven target points.The designed depth is 2121 m,but actual total depth is 2153 m.The horizontal interval and displacement are 728.48 m and 1120 m respectively.It requires high control accuracy of hole trajectory to use stairs horizontal wells to develop.Also it is difficult to operate.Due to formation factors,the slant building-capacity of tools gets poorer,which makes No.1 target impossible to land normally.So screwdrills with high angle are applied to carry out non-filling suspended sidetracking.Then the borehole is filled naturally,and as a result normal landing is attained.Based on adjusting drilling assembly,drilling parameters,and optimizing oil casing strings,the well is completed successfully,fulfilling the demand of design.It does not only lead to good economic benefits,but also provides valuable experience for the operation of horizontal wells in this area.