苏北盆地海安凹陷曲塘次凹阜三段成藏条件分析

苏北盆地海安凹陷曲塘次凹阜三段油藏的油源主要来自于阜二段烃源岩,研究区内阜二段有效烃源岩发育厚度较大,有机质丰度高、类型好,达到了成熟的演化阶段,属于好的生油岩,为研究区阜三段油藏提供了充足的油源。研究区阜三段砂岩发育,属于中孔低渗储层,储集性能较好;阜四段湖相泥岩是研究区阜三段油藏的区域性盖层,封盖性能良好,利于阜三段油气的保存;阜三段油气的运移通道主要是下切至阜二段的断层以及微裂缝,阜二段烃源岩生成的油气在异常压力的驱动下,向上运移至阜三段的储集层成藏。

Reservoir forming conditions of the third member of Funing formation in Qutang sub sag,Hai'an Sag in Subei Basin

Oil source of the third member of Paleogene Funing formation in Qutang sub Sag,Hai'an Sag in Subei basin was mainly from source rock of the second member of Funing formation.The effective source rock of the second member of Funing formation in the study area,which belonged to good source rock,with characteristics of favorable thickness,high abundance of organic matter,good type and mature evolution stage.Therefore,it provided sufficient oil source for reservoir of the third member of Funing formation in the study area.The third member of Funing formation widely developed sandstone,and it belonged to the middle porosity-low permeability reservoir,with favorable reservoir properties.Lacustrine mudstone of the fourth member of Funing formation was the regional seal of the third member of Funing formation,which had good seal ability and was beneficial for hydrocarbon preservation.The migration pathway of the third member of Funing formation was mainly faults and micro fractures which undercut to the second member of Funing formation.Oil and gas generating from the source rock of the second member of Funing formation in the drive under abnormal pressure migrated upward to the third member of Funing formation reservoir.