Hydrocarbon accumulation pattern and exploration direction in Baiyinchagan Sag of Erlian Basin

From the geological setting and structural situation of the Baiyinchagan Sag, through typical reservoir research, several different hydrocarbon accumulation patterns were built. Four of them were distinguished, namely fault-nose, fault block, lithologic type and onlap stratigraphic type. Three sets of source rock and two sets of reservoir were developed in the Bayanhua Group of the Lower Cretaceous in the Baiyinchagan Sag. Geochemical research shows that the main source rocks in the second member of the Aershan Formation and the Tenggeer Formation are already in hydrocarbon-generating peak. The source rocks and reservoirs are connected and superimposed, which provides perfect conditions for oil and gas migration. The fundamental condition of hydrocarbon accumulation and basic reservoir distribution were analyzed. The results suggest that nearshore subaqueous fans are the prior exploration field.