摘要
The southwest margin of the Qikou Sag is a flexural gentle slope formed by the deformation of a drape structure due to its underlying basement lifting. The sedimentary period of the Lower Member 1 of Shahejie Formation is the maximum extensional time of the Paleogene lacustrine basin. Debris from source areas is in shortage. In the broad littoral-shallow lake, hundreds of square kilometers of lacustrine carbonates are deposited and distributed stably. The main lithologies of the sediments are biolithite and dolomite (micritic dolomite and dolomitic limestone), and the dolomites are mainly middle-late buried dolomite and penecontemporaneous dolomite. Drilling exploration practices show that the lacustrine dolomite reservoirs are characterized by medium burial depth and regional petroleum accumulation and are a new exploration area for Paleogene oil and gas.