澳大利亚南缘Otway盆地油气地质特征

Petroleum geology features of Otway Basin in South Australia

以石油地质理论为基础,利用区域地质、地震以及钻井资料,对澳大利亚南缘Otway盆地的石油地质特征进行综合分析。研究表明,盆地经历了早期裂谷、晚期裂谷和裂后被动大陆边缘3个演化阶段,发育2套证实的生储盖组合,第1套下白垩统河流—湖泊相Crayfish生储盖组合主要分布在北部的陆内裂谷带,油气发现集中在Penola坳陷;第2套下白垩统三角洲—滨岸相Shipwreck生储盖组合主要分布在南部的边缘海裂谷带,油气发现集中在Mussel地台和Shipwreck凹陷,已发现油气绝大部分来自该套生储盖组合。

The paper analyzes the petroleum geology features of Otway Basin in South Australia based on petroleum geology theory and by using the data of areal geology,seismic and drilling.The study shows that Otway Basin experienced three development stages of early rifting,late rifting,and post-rifting passive margin and two sets of source-reservoir-cap assemblages were developed in Otway Basin.The first set,Crayfish source-reservoir-cap assemblage of fluvial-estuary sediment in lower Cretaceous,was mainly distributed in northern intracontinental rift zone;and it is found that oil is concentrated in Penola Depression.The second set,Shipwreck source-reservoir-cap assemblage of delta shoreland sediment in upper Cretaceous was mainly distributed in southern marginal rift zone;it is found that oil is concentrated in Mussel Platform and Shipwreck Depression in eastern Otway Basin;and most of the oil reserve came from the second set of source-reservoir-cap assemblage.