Abstract: Gas shales is important unconventional gas reservoirs in which much of the gas is stored in the adsorbed state. In order
to study adsorption capacity of natural gas and controlling factors of Longmaxi Formation in Lower Silurian from Well Yuye 1 at
the southeast of Chongqing，a series of measurements including pore structure and volume，mineral composition，total organic
carbon（TOC），vitrinite reflectivity（Ro）and adsorption isotherms are made. The results show that saturated adsorption VL are
1.253.90 m3/t with an average of 2.17 m3/t；Langmuir pressure constant pL are 1.909.48 MPa with an average of 3.69 MPa.
Saturation adsorption capacity has a negative correlation with micropores volume，and a positive correlation with mesopores
volume and macropores volume. The clay mineral influence adsorption capacity of the shale through controlling micropore and
mesopore volume，while quartz through controlling macropore volumes. Organic carbon content on the adsorption capacity
of shale may be mainly due to its control over development of the macropores. In addition，the strong adsorption for gaseous
hydrocarbons due to characteristics of the surface hydrophobicity and dissolution of gaseous hydrocarbons in the amorphous
structure of asphalt have a certain impact. When Ro> 2.0%，there is a positive correlation between saturation adsorption capacity
and Ro，which may be related with the development of microfractures in the organic matter with high maturity resulting in the
increase of macropore volume.

Key words: black shale, adsorption capacity, organic carbon content, mineral composition, controlling factors