The reservoirs of the mediumrank coal characterize low gas content, low gas saturation, good permeability, and high energy in Hedong area of Shanxi, China.
中国山西河东地区中阶煤储层的含气量比较低、含气饱和度低，而储层渗透性好，储层能量比较大；
2
The variation of medium pore diameter and porosity factor is in accordance with that of the pore volume, showing a high permeability of low rank coal reservoirs.
中值孔径、孔隙率的变化特征与孔容一致，预示了低煤级煤储层较高的基岩渗透率。
3
The main reason for the rise of the coal rank and its composition transformation is the process of regional metamorphism and the influence of medium conditions around it.