Fig. 11

Diagram of organic matter type discrimination for dark mud shale in the Tiemulike formation. a Discriminant diagram of organic matter type using the correlation between H/C and O/C, b Discriminant diagram of organic matter type using the correlation between HI index with Tmax, c Microscopic components in the dark mudstone of the Tiemulike Formation in Well Ning 3, d Triangular diagram of organic matter type using the relative composition of Sterane (this figure is generated in CorelDRAW 2018 software, https://www.coreldrawchina.com/).