关键词: 二连盆地, 乌里雅斯太凹陷, 层序地层, 成藏模式, 坡折带, 油气分布特征

Abstract: Wuliyasitai Sag in Erlian Basin is the Cretaceous fault-through sag and has the single-fault overlap structure. The particular geologic features and reservoir-forming characteristics of Wuliyasitai Sag show that the slope break zone in this sag is the main oil accumulation unit. The litho-stratigraphic reservoir is the main reservoir pattern of the sag. The hydrocarbon distribution, accumulation and enrichment laws indicate that oil and gas mainly exist between two lacustrine flood surfaces and mainly distributed along unconformity surface, lacustrine flood surface and fault surface. The rapidly subsided unconformity surface is favorable to form the stratigraphic reservoir. The slope break zone controlling the strata and facies of this sag plays obvious role in the distribution of oil and gas which is strictly controlled by sedimentary system. The hydrocarbon accumulation has selectivity on genetic type of sand body, while oil and gas enrichment is controlled by favorable sedimentary facies belt and reservoir facies belt.

Key words: Erlian Basin, Wuliyasitai Sag, sequence stratigraphy, reservoir-forming pattern, slope break zone, hydrocarbon distribution feature