Dynamic of Mesozoic Hydrocarbon Secondary Migration in Zhenjing Oilfield,Southwestern Ordos Basin
鄂尔多斯盆地镇泾地区中生界油气二次运移动力研究

The Mesozoic reservoirs in Zhenjing oilfield is characterized by tight reservoirs, low permeability, low abundance and large reserves. It has favorable exploration potential which is shown by the drilled high-yielding wells. Previous studies indicate that there are multiple dynamic systems for hydrocarbon migration and accumulation in the southwestern Ordos basin. And different systems have different dynamic and carrier path for secondary migration. Through the research on buried history, mudstone compaction curve and physical property of reservoirs, it is concluded that the dynamic of secondary migration in Chang8 Member with ultra-low permeable reservoir is overlying abnormal pressure but Yan'an reservoir is buoyancy. Besides, hydrocarbon in Chang6 Member reservoir which is characterized by low permeability accumulated through underlying abnormal pressure mainly and buoyancy locally. Furthermore, permeable bed is the chief carried path in Chang8 Member, while fracture becomes the primary path in Chang6 Member. Permeable bed is the subordinate way for Chang6 Member reserviors. As for Yan'an Formation, various channels including fracture, unconformity and permeable bed could carry hydrocarbon. From the study on dynamic and carrier path of secondary migration, tracking the hydrocarbon movement can become more accurate and exploratory theories for further exploration.