Dongyun formation, Oligocene series in Dalujia area is on of the main production formation of Linpan oil field deposition system is mainly made up by the delta from part, and its sand body genetic type includes river-ountain, sublacustrine distributary channel, sublacustrine levee, sublacustrine crevassesplay, distal bar, sheet coveting in delta front subfacies, which have been identified through comprehensive use of core, logging and well log data. Vertically, all these microfacies can be induced into three typical depositional sequences; uniform, decreasing and increasing upward respectively. In addition, all these microfacies identified in the area are the result of multisuperstition in the geologic time. And the interfaces are not always the interfaces of single sand beds. Through all studies inthis area and by the analysis of the deposition source from the west-north direction, the driving way of river, and the locate form extending to east-south or south, the data in this area is determined to be river-controlling type. Finally, a 3-D depositional faces model of this area has been induced, and in this model sublacustrine distributary channel and river-mouth barare in the center and the other microfacies are around them.
