鄂尔多斯盆地姬塬地区延长组石油运聚规律研究

Petroleum migration and accumulation of Yanchang Formation in Jiyuan area,Ordos Basin

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-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-连通砂体-储层"连续式充注成藏模式和"源岩-微裂缝-储层"幕式充注成藏模式。

Based on the analysis of source rocks,reservoir,dynamics and migration pathways of Yanchang Formation in Jiyuan area,Ordos Basin,the rule of petroleum migration and accumulation is analyzed.Dark mudstones were developed in the maximum lake flooding period of Chang 7,which are the main source rocks.Most of the reservoirs are extra-low permeability reservoirs.The intergranular pore is the 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 Yanchang 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.