This study evaluates the unconventional oil and gas exploration potential of the Cenozoic residual basins in southern Jiangsu

focusing on Jintan Basin. Utilizing a range of data sources

including drilling records

core analyses

logging data

and laboratory tests from Well-J9

we extensively analyzed the geological features of the fourth member of Funing Formation. These analyses encompass rock mineral composition

sedimentary characteristics

organic geochemical properties

and reservoir qualities. Findings indicate that the fourth member of Funing Formation was deposited in a semi-closed to closed saline sedimentary environment

predominantly characterized by shallow to semi-deep lakes. This me

mber is marked by substantial mud shale thickness（exceeding 250 m in deep concave zones）

low organic matter abundance（average total organic carbon（TOC）of 1.02%）

and a moderate degree of thermal evolution（vitrinite reflectance（

R

o

）ranging from 0.81% to 0.85%）

providing a fundamental basis for shale oil hydrocarbon generation. Additionally

the presence of fractures and porous shale reservoir spaces

coupled with a high content of brittle minerals

suggests favorable conditions for the development of complex fracture networks during subsequent fracturing interventions. Considering the oil and gas shows in existing boreholes

it is posited that the fourth member of Funing Formation

particularly near the Maoshan tectonic push-over zone

holds medium to low maturity shale oil exploration potential in southern Jiangsu.