Nanoscale Pore Structure Characterization and Permeability of Mudrocks and Fine-Grained Sandstones in Coal Reservoirs by Scanning Electron Microscopy, Mercury Intrusion Porosimetry, and Low-Field Nuclear Magnetic Resonance

Table 1

Petrographic characteristics of the rock samples investigated in this study.

Sample number	Lithology	Macroscopic	Petrographic characteristics
JH-Y	Shale		Brown laminar shale
JH-S	Sandstone		Caesious sandstone with good gradation and fine psephicity of grains
NT-Y1	Shale		Dark grey laminated silty shale
NT-Y2			Grey laminated silty shale
NT-Y3			Brown laminated silty shale
NT-M1	Mudstone		Gray massive mudstone
NT-M2			Gray massive mudstone
NT-M3			Yellow-gray massive mudstone
NT-M4			Gray massive mudstone
NT-M5			Dark gray massive mudstone
NT-M6			Gray massive mudstone
NT-S	Sandstone		Grey white fine-grained sandstone with good gradation of detrital grains

bar for the macroscopic images: .