Abstract: The exploration area in Southern Sichuan is present in ancient strata,where difficulties such as poor drillability,slow penetration rate,high drilling cost and low investment return exist.To achieve an efficient shale gas exploration in this exploration area,we carried out activities including well structure optimization,optimal and fast drilling technology and economic cost analysis on the basis of analyses on drilling technical difficulties in the exploration area and shale gas reservoir stimulation technology requirements.As a result,a drilling program based on three times of spudding and completion with ø139.7 mm casings was developed,which guided the design of WY1 and YY1 exploratory wells successfully and provided technical guidance for the first round shale gas exploration in Southern Sichuan.