Geological characteristics and development potential of transitional shale gas in the east margin of the Ordos Basin, NW China

KUANG Lichun,DONG Dazhong,HE Wenyuan,WEN Shengming,SUN Shasha,LI Shuxin,QIU Zhen,LIAO Xinwei,LI Yong,WU Jin,ZHANG Leifu,SHI Zhensheng,GUO Wen,ZHANG Surong

Fig. 8. SEM characteristics of pores and fractures in the Shan-2 shale samples from the east margin of the Ordos Basin. (a) Intergranular and intragranular pores of minerals; (b) calcite-dissolved pores; (c) slit-shape pores between book-like kaolinite layers; (d) massive intercrystal pores in pyrite; (e) nano-scale pores in organic matter, round or oval in shape, small in size and even in distribution; (f) numerous nano pores in organic matter, mostly irregular in shape and good in connectivity; (g) shrink fractures around organic matter; (h) massive interlayer micro-scale pores and fractures in clay mineral aggregates; (i) micro-scale intergranular pores and fractures of mineral.