The sedimentary facies

thickness

distribution

organic matter types and content

maturity

porosity

and gas content

of the Upper Ordovician-Lower Silurian dark shale in the Sichuan Basin and its periphery are investigated by field observation and sampling on 25 outcrops and laboratory test of adsorbed gas content

geochemical and physical parameters.In comparison with the major producing gas shales in U.S.

the shale in the study area features in favorable sedimentary facies

large thickness

high TOC

high maturity

high porosity

and high gas content

all being favorable geological conditions for shale gas reservoir development.Parameter models were built for predicting shale gas play fairways.The results show that the shale gas play fairways in the study area occur in the Southern Sichuan-Northern Guizhou

Western Hubei-Eastern Chongqing and Northeastern Sichuan(Chongqing)-Northwestern Hubei

among which the Southern Sichuan-Northern Guizhou play fairway is relatively high in gas content

thus is most prospective in shale gas exploration at present.With the measured gas content

the volumetric method gave a resource volume in the range of 2.2-8.5 TCM and a median value of 5.3 TCM.