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. 4. Sedimentary characteristics of the Shan23 sub-member in Well Daji 51, Daning-Jixian area in the east margin of the Ordos Basin. (a) Core image of black organic-rich shale with foliations, 2286 m; (b) core image of carbonate bioclastic shale, 2270 m; (c) core image of silty shale with siltstone, 2261 m; (d) thin section image of shale of tidal flat-lagoon facies in deep-water still reduction environment, plane polarized light, 2295 m; (e) thin section image of shale with sideritization of charcoal debris, indicating reducing environment, plane polarized light, 2282 m; (f) thin section image of silty shale with plant debris, plane polarized light, 2261 m.