鄂尔多斯盆地中生界成藏组合划分与分布评价

对鄂尔多斯盆地中生界三叠系延长组成藏组合进行了系统的划分。在划分过程中,主要根据成藏组合的定义,并充分考虑目的层的:①烃源岩分布和砂体分布;②构造、古构造分布、主要断裂分布及油气运移疏导系统空间分布;③所在成藏组合主要烃源岩分布;④所在成藏组合盖层分布,特别是区域性盖层分布。另外,还考虑目前认识的构造圈闭及可能的其他圈闭分布情况,并分析含油气系统的保存情况。盆地中生界延长组划分为6个成藏组合:长₁₀-长₇下部成藏组合、长₇-长₅中部成藏组合、长₇-长₄₊₅中部成藏组合、长₄₊₅-长₃上部成藏组合、长₄₊₅-长₂上部成藏组合和长₄-长₁上部成藏组合。通过对各组合的生、储、盖层分析,认为中生界成藏组合主要分布在伊-陕斜坡西北部、东南部、西南部和天环坳陷南部。

Identification and distribution of the Mesozoic plays in Ordos Basin

This paper systematically identifies plays in the Triassic Yanchang Formation of the Mesozoic in Ordos Basin.The play division is mainly based on the play definition and the following characteristics of target beds:(1)distributions of source rocks and sandstone reservoirs;(2)distributions of structures and paleo-structures,main faults and carrier systems;(3)distributions of main source rocks for each play;(4)distribution of seals especially regional seals for each play.In addition,the distribution of known structural traps and other possible structural traps as well as the preservation of petroleum system are also considered to identify play.Six plays were identified in the Triassic Yanchang Formation in Ordos Basin:MemberⅩto Member Ⅶ play,Member Ⅶ to Member Ⅴ play,Member Ⅶ to Member Ⅳ+Ⅴplay,upper of Member Ⅳ+Ⅴ to Member Ⅲ play,Member Ⅳ+Ⅴ to Member Ⅱ play and Member Ⅳ to MemberⅠ play.According to the analysis of source rocks,reservoirs and cap rocks in different plays,the Mesozoic plays are mainly distributed in the northwest and southeast and southwest parts of Yishan slope and the south part of Tianhuan depression.