鄂尔多斯盆地晚三叠世延长组湖侵期沉积特征  

Sedimentation during the transgression period in Late Triassic Yanchang Formation,Ordos Basin

作　　者：喻建[1,2,3] 杨亚娟[3] 杜金良[1,3] 

机构地区：[1]西北大学 [2]中国科学院地质与地球物理研究所 [3]中国石油长庆油田勘探开发研究院

出　　处：《石油勘探与开发》2010年第2期181-187,共7页Petroleum Exploration and Development

摘　　要：鄂尔多斯盆地晚三叠世延长组沉积阶段经历了长9段沉积期、长7段沉积期、长4+5段沉积期3次主要湖侵期。运用钻井、测井等资料,综合分析了湖侵期储集砂体的沉积相类型、沉积演化规律,认为在湖盆西侧储集砂体主要为半深湖—深湖相浊积砂,东侧主要为深水型三角洲前缘水下分流河道砂。各湖侵期砂体展布特征具有差异性,长9段砂体规模大,分布范围广,单层砂体厚;长7段三角洲砂体规模较小,浊积砂体发育,局部地区具有叠合连片特征;长4+5段盆地东北三角洲砂体延伸较远,横向连片性好,三角洲前缘水下分流河道砂体单层厚度薄,纵向多层叠加。研究还表明,湖侵期发育优质烃源岩,砂体具有较好的储集空间,生储配置关系好,易形成原生油藏,是下一步勘探的目标领域。The Late Triassic Yanchang Formation in the Ordos Basin experienced three transgression periods of Chang 9,Chang 7 and Chang 4＋5.Based on the drilling and logging data,the types of sedimentary facies and the evolvement of sediments are analyzed in the transgression periods.It is concluded that the reservoir sandstones are mainly semi-deep to deep lacustrine turbidites in the west of the lake basin,and are deep-water delta front distributary channel sands in the east.Distribution characteristics of sandstones are distinct in every transgression period.In particular,the Chang 9 sandstones are wide,intensive,and thick in monolayer;the Chang 7 sandstones are small,with turbidite sandstones developed,and stacked and connected locally;the Chang 4＋5 sandstones in the northeastern delta of the basin are far extended,with good horizontal connection,thin monolayer of deep-water delta front distributary channel sands,and multiplayer superimposition vertically.The study also shows that in the transgression periods,good source rocks were developed,sandstones had good reservoir space,and the source,reservoir and seal rocks had good relationships,prone to form primary hydrocarbon reservoirs,and they are targets for exploration.

关 键 词：鄂尔多斯盆地 晚三叠世 延长组 湖侵期 砂体展布特征 浊积砂体 

分 类 号：TE122.1[石油与天然气工程—油气勘探]