Abstract：Using samples from Nanchuan,Qijiang and Fuling in Chongqing,the characteristics of shale reservoir pores and mircofractures in Wufeng and Longmaxi formation were studied by methods of Argon ion polishingfield emission scanning electron microscopy( FE-SEM),high pressure mercury intrusion,low temperature nitrogen adsorption and X-ray diffraction. The results show that a variety of pores were identified by formation and appearance characteristics,such as organic nanopores,mineral pores in rock skeletons,interparticle pores between clay minerals,et al,and the main reservoir space is nanopores with strong adsorption ability especially the organic nanopores. Qualitative and quantitative observations were combined to establish the corresponding relationship between morphology-formation pores and the pore size distributions in shale reservoir,and the results showed that the nano-pores in organic matter and matrix minerals could correspond to the interval which the pores of shale reservoirs were developed centralizedly.

Keyword：shale gas;nanopores;pore types;pore size distribution;influencing factors;