鄂尔多斯盆地旬邑地区长8_1致密油勘探程度不高,勘探效果差。通过旬邑地区24口井230m岩心观察、30口井岩心测试及18口井烃源岩测试,结合65口井测井资料、20口井试油资料对研究区长8_1致密油成藏条件进行分析,并进一步研究成藏主控因素。结果表明:研究区致密油成藏条件优越,油藏分布复杂。油藏分布主要受沉积微相、储层物性控制。砂厚为10m~20m,单砂体为4m~6m的区域易成为油层;储层渗透率大于0.14×10~(-3)μm2,孔隙度为5.9%以上致密油富集。水下分流河道砂体中部为致密油富集的主要区域。储层非均质性影响油气充满程度,非均质性越强,含油性越差。裂缝、隔夹层等油气运移条件影响油气充注,进而影响油藏分布。裂缝可降低油气充注阻力,有利于油气聚集。隔夹层特别是钙质夹层则会增加充注阻力,对油气成藏不利。寻找良好砂体、优质储层及裂缝为旬邑地区长8_1致密油勘探的关键。 The Ordos Basin Xunyi area Chang 8_1 tight oil exploration degree is not high, the exploration effect is poor. According to the 230m core observation of 24 wells in Xunyi area, the core test of 30 wells and the test of source rock of 18 wells, the well logging data of 65 wells and the data of 20 wells were used to study the tight oil reservoirs in Chang 8-1 of the study area Analysis, and further study of the main controlling factors. The results show that the tight oil reservoirs in the study area are well-formed and the reservoir distribution is complicated. The reservoir distribution is mainly controlled by sedimentary microfacies and reservoir physical properties. The sandstone thickness is 10m ~ 20m and the single sand body is 4m ~ 6m. The permeability of the reservoir is more than 0.14 × 10 ~ (-3) μm2, and the porosity is more than 5.9%. The middle part of submarine distributary channel sandstone is the main area enriched with tight oil. Reservoir heterogeneity affects the degree of oil and gas filling, the stronger the heterogeneity, the worse the oiliness. Fractures, interbeds and other hydrocarbon migration conditions affect the filling of oil and gas, thereby affecting the reservoir distribution. Cracks can reduce the filling resistance, is conducive to the accumulation of hydrocarbons. Intercalation, especially calcareous intercalation, will increase charge resistance and adversely affect hydrocarbon accumulation. Finding a good sand body, high quality reservoirs and fractures is the key to the exploration of the Chang 8_1 tight oil in Xunyi area.