Biostratigraphy and reservoir characteristics of the Ordovician Wufeng Formation-Silurian Longmaxi Formation shale in the Sichuan Basin and its surrounding areas, China

WANG Hongyan,SHI Zhensheng,SUN Shasha

Fig. 3. Composition and characteristics of graptolite zones in the Longmaxi Formation of Sichuan Basin and its surrounding areas. (a) Avitograptus ex gr. avitus (Davies), Well W202, LM1-2; (b) Avitograptus avitus, Well WX2, LM2-LM3; (c) Dimorphograptus nankingensis, Well JY8, LM4; (d) Pseudorthograptus sp., Well JY1, LM4; (e) Dimorphograptus nankingensis, Well JY8, LM4; (f) Cystograptus vesiculosus, Well JY8; (g) Cystograptus vesiculosus, Well W204, LM4; (h) Coronograptus cf. cyphus, Well JY1, LM5; (i) Coronograptus cyphus, Well W202, LM5; (j) Rastrites guizhouensis, Well JY1, LM6; (k) Coronograptus cf. gregarius, Well JY8, LM6; (l) Glyptograptus cf. tamaricus, Well JY1, LM6; (m) Coronograptus cf. gregarius, Well JY8, LM6.