Abstract: In order to meet the requirements of oilfield explora- tion and development,on the basis of principles of drilling engineering design optimization,using domeslic and inter- national successful experiences for reference,the opti- mized design on casing and bit size under different drilling conditions is provided.According to well types,forma- tion characteristics and reservoir quality,the research on drilling fluid design,cementing and completion optimiza- tion has been developed.At the same time,some new drilling techniques have been put into practice and a- chieved great effect.