In recent years

the exploration of Longmaxi Formation in Sichuan Basin has been successful

but the shale gas of the complex structural belt’s Longmaxi Formation are still the next areas for exploration. Therefore

it is necessary to carry out systematic researches on the Sanbaiti section in Mount Huaying of high-steep structural belt in Sichuan Basin

so as to provide ideas for the further exploration breakthrough. The section’s lithology

paleontology

mineral composition

geochemical characteristics

pore type and structure are studied

and compared with the drilling wells of adjacent areas. The findings are as follows. ①The outcrop in Mount Huaying section is well exposed. The shale strata from Wufeng Formation to the bottom of Longmaxi Formation are complete and continuous. Wufeng Formation is divided into two sections

and the Longmaxi Formation（no top） is divided into three sections. The WF2-LM9 graptolite biozone is well developed. From the bottom to the top

the sedimentary environment changed from reduction to oxidation

and the biogenic siliceous environment has been destroyed. The injection amount of terrigenous debris increases

and the abundance of organic matter shows a downward trend. The organic matter in Long-1 member of Wufeng Formation is relatively rich

and the content of brittle minerals is high. The reservoir space is dominated by organic pores

followed by inorganic pores and microfractures. The pore structure is dominated by ink bottles

and a small amount of slit pores. ②For the Hirnantian-Rhuddanian

although the Sanbaiti section of Mount Huaying is located in the deep-water shelf zone in southern Sichuan

the underwater highland micro-paleogeomorphology is locally developed. Due to the influence of undercurrent and other factors

the deposition thickness of organic-rich shale is thin. So that

the micro-paleogeomorphology has an important influence on the material basis of shale gas formation

which can provide ideas for the further evaluation of Longmaxi Formation. ③The formation of organic-rich shale reservoirs in Long-1 member of Wufeng Formation is mainly controlled by the combined action of volcanism

source supply and reduction environment.