再论鄂尔多斯盆地延长组长7_(3)砂层组与烃源岩相关的高伽马砂岩

Review of the High Natural Gamma Sandstones Associated With Source Rocks in the Chang 7_(3) Submember of the Yanchang Formation,Ordos Basin

针对自然伽马等常规测井系列长期仅能将鄂尔多斯盆地延长组长7_(3)砂层组大规模发育的与烃源岩相关的高伽马砂岩解释为“油页岩等优质烃源岩”的问题,根据岩心观察及测录井资料、电子探针薄片和大量页岩油实际生产资料的分析,对长7_(3)砂层组内与烃源岩相关的高伽马砂岩的定义、成因以及其发育特征与长7油层组页岩油试油效果的关系进行了探索性的研究。研究表明,鄂尔多斯盆地长7_(3)砂层组内与烃源岩相关的高伽马砂岩可划分为狭义和广义两种类型,高放射性的成因可能与深部热水作用有关,首次发现其发育特征与长7油层组页岩油试油效果关系密切。该项研究对鄂尔多斯盆地延长组长7油层组页岩油的大规模高效勘探与开发具有重要的理论和现实意义。

For the high natural gamma sandstones associated with source rocks in the large-scale Chang7_(3)submember of the Triassic Yanchang Formation in the Ordos Basin,they had long been identified as high-quality source rocks(e.g.oil shales)from conventional well log profiles(e.gnatural gamma ray well logs).Based on core observation,and integrated analyses of well logging,logging,the electron microprobe and numerous actual production data of shale oil,apreliminary research about the definition was proposed.The genesis of these high natural gamma sandstones associated with source rocks in the Chang 7_(3) submember was discussed,along with the correlation between its development and testing effect of shale oil of the Chang 7 Member.We suggest that they are narrow and broad types can be divided in the Chang 7_(3) submember in the Ordos Basin,and that their highly radioactive genesis maybe related to deep hydrothermal sedimentation It is newly found that there isa close correlation between their development and testing effect of shale oil of the Chang 7 member.This study has important theoretical and practical significance for the large-scale and efficient exploration and development of shale oil in the Chang 7 Member in the Ordos Basin.