鄂尔多斯盆地志靖——安塞地区延长组首次湖侵期沉积特征及其石油地质意义  

Sedimentary characteristics and petroleum geological implications of the first lacustrine transgression period of Yanchang Formation in Zhijing-Ansai area of Ordos Basin

作　　者：马瑶[1] 李文厚[1] 刘哲[2] 黄海鱼 郭懿萱[2] 李莹[2] 

机构地区：[1]大陆动力学国家重点实验室(西北大学)/西北大学地质学系,陕西西安710069 [2]中国石油长庆油田公司勘探开发研究院,陕西西安710018 [3]陕西煤业化工集团有限责任公司神木红柳林矿业有限公司,陕西神木719300

出　　处：《地质通报》2015年第5期972-982,共11页Geological Bulletin of China

基　　金：国家自然科学重点基金项目(批准号:41330315);中国地质调查局项目(编号:12120114009201);国家科技重大专项(编号:2008ZX05005-004-007HZ)

摘　　要：通过沉积物岩石学特征、粒度分布特征、沉积构造与生物化石特征、单井分析等综合方法,对志靖—安塞地区长9油层组沉积相发育及分布特征进行了研究。结果表明,鄂尔多斯盆地志靖—安塞地区在首次湖侵期长9期发育三角洲-湖泊沉积体系,主要发育三角洲前缘亚相和浅湖亚相。长92期研究区北部大面积发育三角洲前缘沉积,西南部发育小面积三角洲前缘沉积,浅湖面积较小,呈喇叭状向东南方向开口。长91期沉积格局基本上继承了长92期的特点,但浅湖的范围有所加大。三角洲前缘水下分流河道砂体整体上呈北东—南西向条带状展布。长9期湖侵过程形成了具生烃潜力的泥岩,主要分布在吴起—志丹—安塞一带,在志丹东南部区域最厚,可达20m,并呈现向东南方向继续变厚延伸的趋势。储集空间的存在和烃源岩的发育使得研究区长9储层具有较好的勘探前景。Using comprehensive methods such as the features of sediment color, particle size distribution, sedimentary structure, transitional fossils and single well analysis, this paper discusses the development and distribution characteristics of sedimentary facies with the purpose of guiding the oil and gas exploration and exploitation of Chang 9 reservoir which is newly developed. The results show that the delta-lacustrine sedimentary system was developed in Zhijing-Ansai area during Chang 9 stage, the first lacustrine transgression period of Ordos Basin, mainly including delta front subfacies and shallow lake subfacies. During the depositional period of the lower part of Chang 9, delta front was mainly developed in the northern part of the study area, and was less formed in the southwestern part. During the depositional period of the upper part of Chang 9, the shallow lake area was small and extended southeastward in the trumpet form. Deposition pattern during the period of the upper part of Chang 9 basically inherited the characteristics of the lower part of Chang 9, except that the shallow lake distribution range was enlarged. Underwater distributary channel of delta front subfacies stretched from northeast to southwest. The mudstone which had hydrocarbon-generating capability was developed during the first lacustrine transgression period, and was distributed around Wuqi-Zhidan-Ansai area, and the greatest thickness lay in the southeast area of Zhidan which was up to 20m. The thickness tended to increase southeastward. The existence of reservoir space and the development of source rock have created favorable conditions for the prospecting work in Chang 9 reservoir.

关 键 词：沉积特征 首次湖侵期 延长组 志靖—安塞地区 鄂尔多斯盆地 

分 类 号：P618.13[天文地球—矿床学]