Abstract: The sidetracking short-radius horizontal well has the same advantage of enhancing oil/gas recovery as the conventional medium-radius and long-radius horizontal wells.Besides,it features in low cost,short cycle,and early benefit.This paper introduces the slim hole sidetracking horizontal well drilling technology from the aspects of the operating characteristics,profile design,the selection of window cutting tools and methods,trajectory control,the selection of measuring methods and tools,as well as the design of drilling fluid of sidetracking short-radius horizontal wells.Based on drilling practice,it as well shows the structure of drilling tools,technological measures,and cautions for each drilling stage.The slim hole sidetracking and short-radius horizontal well drilling technology has been successfully applied to the exploration and development of Ordovician reservoir in Tahe Oilfield.Good effect has been attained.This may be good reference to drilling design and operation of similar types of wells in the future.