鄂尔多斯盆地东部下奥陶统储层含油气差异性的关键是储层储集条件的非均一性，根本原因是基底构造古隆起及凹陷、岩相古地理、成合作用和占岩溶的综合影响．其中，基底构造古隆起及凹陷是基础，岩相是条件，成岩作用是关键，古岩溶是决定性因素。 The key to the difference of oil and gas in the Lower Ordovician reservoir in the eastern Ordos Basin is the heterogeneity of reservoir conditions. The fundamental reason is the basement tectono-paleo-uplift and depression, lithofacies palaeogeography, symbiosis and the combined effect of karstification . Among them, the basement structure paleo-uplift and depression is the foundation, lithofacies conditions, diagenesis is the key, paleokarst is the decisive factor.