Abstract: Based on integration of drilling,core,outcrop and logging data,this paper comprehensively studied the geological characteristics of the Lower Jurassic Da'anzhai shale gas play in Fuling,southeastern Sichuan Basin in such aspects as spatial distribution of organic-rich shales,geochemical characteristics,mineral components,shale porosity and permeability conditions,and geomechanical properties.We quantitatively evaluated such characteristics as TOC content,R_o,gas content,porosity,brittleness,mineral composition and rock mechanical parameters.We believe that the shale gas play is analogy basically to Bakken shale in North America.The Da'anzhai mudstone-shale features in frequent interbedding with limestone and sandstone,and the deep to semi-deep lacustrine shales are organic-rich exploration targets.The limestone in the upper Da'anzhai is 10-30 m thick and has low porosity and extra-low permeability.The lower Da'anzhai shale with interbedded thin limestone and sandstone has well-developed micro-fractures and high porosity.The shale gas play has an average TOC content of 1.33%,average clay content of 51.7%-56.1%,average quartz content of 33% and on-site measured average gas content of 1.66 cubic metre per ton,and is at high thermal maturity stage of generating gas condensate to wet gas.The Young modulus is 29GPa and Poisson ratio is 0.30,being favorable for the creation of fracture networks through hydraulic fracturing.The middle Da'anzhai shale of shallow lacustrine facies is more favorable for fracture development,thus is the favorable target.A play fairway with an area of 820 km² is identified.

Key words: hydraulic fracturing, organic-rich shale, shale gas, Da’anzhai Member, Jurassic, Fuling area, Sichuan Basin