At present

the Wufeng-Longmaxi Marine high quality shale is the only case that has been commercially exploited in China. Taking Huangying section in Wulong District

Chongqing as an example

the characteristics of sedimentary geochemistry and their interrelationship of Marine high quality shale are studied by the field observation and field measurement combined with laboratory experiment analysis. The results show that: firstly

the black siliceous shales of Wufeng Formation and dark gray shell argillaceous limestone of Guanyinqiao Formation are exposed from bottom to top in Huangying section

which reflects the sedimentary environment from deep water shelf to shallow sea and then to deep water shelf. Secondly

the biostratigraphy of outcrop layer is continuous and intact

and the Kaidian-Rudan WF2-LM5 graptolite zone can be recognized. The graptolite type

content and preservation characteristics are closely related to the sedimentary environment. Thirdly

the Wulong area is located in the hydrocarbon generation center of the deepwater shelf. The high-quality shale has large thickness

superior static index

high hydrocarbon generation intensity and good material basis for shale gas enrichment. Fourthly

Wulong area is the sweet spot of both shale gas exploration and development because of the good accumulation and enrichment conditions of shale gas in small layer ①—④.