Palaeogeomorphology and palaeo-environment conditions are the main environmental factors affecting the sedimentation. Due to the frequent water change

complex terrain and high difficulty in seismic identification and tracking

the reconstruction research of palaeogeomorphology and palaeo-environment in the 3rd member of Funing Formation in Qintong Sag of Subei Basin is still insufficient

which affects the overall exploration evaluation of the study area. In

order to clarify the palaeogeomorphology and palaeo-environmental conditions of the 3rd member of Funing Formation in Qintong Sag during the deposition period

the formation core

logging data and rock material data are comprehensively analyzed. The semi-quantitative reconstruction of the palaeogeomorphology of the 3rd member of Funing Formation is carried out by combining the palaeo-geologic map

impression method and residual thickness method

and the pyrolysis experiment data

TOC

and trace element content data of 33 rock samples from two wells are selected to carry out the palaeo-environment reconstruction analysis. Accordingly

paleogeomorphology reconstruction in map form and the curves of palaeo-environment changes of the 3rd member of Funing Formation in Qintong Sag are drawn

which prove that the study area is a half-graben

lower in the South and higher in the North with the convergence across the east-west direction

the climate is warm and humid during the sedimentary period

the water body activity is frequent and recurrent

the water salinity is low

the multiple source is supplied intermittent

the material source input continues to increase

and the deposition rate is fast. Therefore

the corresponding relationship between stratigraphic physical parameters and paleogeomorphology

geochemical parameters and paleoenvironment in the study area are clarified

which provide reference for the further exploration and development.