在分析鄂尔多斯盆地姬塬地区延长组烃源岩、储集层特征、运移动力学特征和运移通道特征等成藏主控因素的基础上,总结了延长组低渗储层的石油运聚规律。延长组长7 段最大湖泛期发育一套暗色泥岩,干酪根类型为腐植2腐泥型,是盆地主要生油岩。储层以低渗透为主要特征,绝大部分属于超低、特低渗储层,储集空间以残余粒间孔为主,孔喉类型以细孔微喉型和微孔微喉型为主。异常高压是石油运移的主要动力,长7 段异常压力的分布与暗色泥岩的厚度有关,在暗色泥岩厚度大的区域,异常压力较大。连通砂体是石油运移的主要通道,成藏期储层相对高渗透是连通砂体成为有效运移通道的基础。微裂缝控制了局部地区延长组油藏的分布及其规模。通过对该盆地的分析,总结出了2 类成藏模式,即“源岩2连通砂体2储层”连续式充注成藏模式和“源岩2微裂缝2 储层”幕式充注成藏模式。

Based on the analysis of source rocks , reservoir , dynamics and migration pat hways of Yanchang Formation in J iyuan area , Ordos Basin , the rule of pet roleum migration and accumulation is analyzed. Dark mudstones were developed in t he maximum lake flooding period of Chang 7 , which are t he main source rocks. Most of the reservoir s are extra-low permeability reservoirs. The intergranular pore is t he main space for reservoir , and the pore throat types are mainly thin-pore with micro-throat and micro-pore with micro-throat . Anomalous pressure is the main dynamic for the hydrocarbon migration , and it is closely related to the depth of the duck mudstone. Connected sand bodies are the main migration pathway , in which high permeability in accumulation stage takes an important part . The reservoir distribution of Yan-chang Formation is partly controlled by micro-fractures. Two types of accumulation patterns including “source rocks-connected sand bodies-reservoir”and“source rocks - micro-fractures-reservoir”are finally summarized.