摘要： 鄂尔多斯盆地延长组长9油层组发育三角洲—湖泊沉积相，三角洲平原分流河道砂体和三角洲前缘水下分流河道砂体是最有利的储集砂体。在沉积相研究的基础上，根据单因素分析多因素综合作图法，选取了地层厚度、较深水沉积岩含量、砂岩厚度、砂地比、自生绿泥石分布、古生物化石分布和沉积构造分布等单因素，对鄂尔多斯盆地延长组长9油层组上下2段的沉积相平面展布特征进行了深入研究，并探讨了其演化规律。研究表明，鄂尔多斯盆地以发育多水系、多物源注入的环湖分布的多个三角洲为特色，东北部地区主要发育曲流河三角洲，西部发育辫状河三角洲，其中以三角洲平原分流河道和三角洲前缘水下分流河道微相较为发育。长9₂沉积期，半深湖沉积在盆地内较为局限，长9₁沉积期湖盆初始扩张达到最大范围，湖岸线向陆推移，湖域面积扩大，半深湖沉积较发育。由长9₂沉积期到长9₁沉积期，鄂尔多斯盆地沉积水体经历了由浅变深的过程，由此在长9₂的顶部沉积了一套具有生烃潜力的油页岩。

关键词: 鄂尔多斯盆地, 三叠系, 延长组, 长9油层组, 沉积相, 单因素分析

Abstract: Delta and lacustrine sedimentary facies are recognized from the Chang 9 interval of the Upper Triassic Yanchang Formation in the Ordos Basin.The deltaic plain distributaries channel sandbodies and deltaic front subaqueous distributaries channel sandbodies are high quality reservoirs.Based on the research of sedimentary facies，according to the single factor analysis and multifactor comprehensive mapping method，the sedimentary facies distribution of the upper and lower parts of Chang 9 interval of Yanchang Formation in the Ordos Basin were studied and mapped.The single factors include strata thickness，content of deep water sedimentary rocks，sandstone thickness，sandstone strata thickness ratio，authigenic chlorite development characteristics，paleontology characteristics，sedimentary structure combination characteristics.Discussion was made about the sedimentary evolution rule of the Chang 9 interval.The results show that the Chang 9 interval of Yanchang Formation was characterized by the deposition of multiple delta sedimentary system which surround the lake and have multiple water systems and multiple provenances.The meandering fluvial deltas were mainly developed in the northeastern Ordos Basin，and the braided fluvial deltas were mainly developed in the western Ordos Basin.The deltaic plain distributaries channel microfacies and deltaic front subaqueous distributaries channel microfacies were well developed.During the depositional period of the lower part of Chang 9 of Yanchang Formation，semi-deep custrine was only developed in the center of the Ordos Basin.During the depositional period of the upper part of Chang 9 interval of Yanchang Formation，the custrine basin began to expanded，lake shoreline moved to the land，lake area enlarged，and the semi-deep custrine deposition greatly developed.From the lower part to the upper part of Chang 9 interval of Yanchang Formation，the water depth changed from shallow to deep.Correspondingly，a set of oil shale with hydrocarbon generating potential are deposited in the study area.

Key words: Ordos Basin, Triassic, Yanchang Formation, Chang 9 interval of Yanchang Formation, sedimentary facies, single factor analysis

中图分类号: 

• P512