Abstract: Northeast Sichuan is rich in sea facies resources,and buried deep gas reservoir with "three high" characteristics as high temperature,high pressure,high hydrogen sulfide content. Geological conditions in the area is very complex,directional well has become a common well-type. The mostprominent problems of drilling is low speed,long life cycle and high costs. Aiming at drilling bottlenecks,carrying out high-angle directional well casing structure optimization study,and determine casing depth based on drilling under complex situations,this paper put forward four open system casing structure optimization programs which revealed Feix-ianguan group and Jialing River group simultaneously,and proposed corresponding fast drilling technology at different well sections. The successful application in HF203 well and HJ203H well with an average penetration rate 2. 01 m/h,and the average drilling cycle of 309 d,has achieved win-win in the drilling speed and safety.