Geochemistry-based sequential stratigraphic classification of shale——With shale of Upper Permian Longtan Formation in well Changye1 in Meishan area of Zhejiang as example

In order to divide stratigraphic sequence more accurately, the organic geochemistry was combined with sequence stratigraphy. The authors combined the organic geochemistry indicators such as TOC, CPI, OEP, chloroform bitumen“A”, (nC21+nC22)/(nC28+nC29) and Pr/Ph and so on with traditional sequence segmentation approach(well log, lithological characters, etc.) of the shale of Longtan Formation of well Changye1 in Meishan area, pointed out that the current issue of sequence classification of well Changye 1, and amended it. The results show that TOC, chloroform bitumen“A”, Pr/Ph and any other indexes play an important role in dividing the sequence, the maximum flooding surface of Member Long1, Member Long2 and Member Long3 all corresponded with the maximum TOC of these members. The TOC of the maximum flooding surface of members Long1, Long2 and Long3 is 2.46%, 1.57%, and 4.84% respectively. The maximum flooding surface of well Changye1 has been adjusted based on this conclusion.