| 陆相前陆盆地沉积充填与层序地层模式探讨——以库车前陆盆地为例 |
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| 引用本文： | 贾进华.陆相前陆盆地沉积充填与层序地层模式探讨——以库车前陆盆地为例[J].现代地质,2009,23(4). |
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| 作者姓名： | 贾进华 |
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| 作者单位： | 中国石油勘探开发研究院,北京,100083 |
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| 摘 要： | 以库车前陆盆地为例,对陆相前陆盆地的形成、沉积充填与层序地层结构、不整合面与层序界面、层序地层组成与其模式、生储盖组合与岩性地层圈闭等关键问题进行了探讨。认为前陆层序是盆缘构造运动的响应,由低位(冲积)体系域、湖侵体系域、高位体系域组成。前陆盆地层序界面表现为构造或沉积不整合面,代表了一次构造幕的发生,其层序地层样式是盆缘造山带构造楔推进作用的结果,是盆地演化的不同阶段的响应,反映了构造运动由强到弱的间歇变化。前陆层序界面代表了沉积结构的大转换,之下为构造稳定阶段的湖相泥岩或膏泥岩,之上为代表构造运动的冲积扇—扇三角洲相的巨厚磨拉石沉积充填。在构造活动期和静止期,盆地不同位置形成不同的沉积充填和地层结构特点。构造活动期以低位(冲积)体系域为主,在毗邻造山带侧以巨厚的冲积扇-扇三角洲-辫状河三角洲相等冲积沉积物为主;构造静止期以湖侵体系域为主,为广泛的河流-湖泊相沉积。沉积厚度从靠近冲断带侧向盆地内逐渐变小。陆相前陆盆地的生储盖组合配置好,储集体广泛分布于低位、湖侵和高位体系域中,以辫状河三角洲和滨湖相为主。其岩性地层圈闭主要分布在前缘斜坡带上,包括沿古隆起边缘的地层超覆不整合圈闭和地层削蚀不整合圈闭,将会成为今后油气勘探的新领域。
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| 关 键 词： | 陆相前陆盆地 沉积充填 层序地层 库车 |
Discussion of Depositional Filling and Sequence Stratigraphy Model of Continental Foreland Basin:Taking the Kuqa Foreland Basin as an Example |
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| JIA Jin-hua.Discussion of Depositional Filling and Sequence Stratigraphy Model of Continental Foreland Basin:Taking the Kuqa Foreland Basin as an Example[J].Geoscience——Journal of Graduate School,China University of Geosciences,2009,23(4). |
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| Authors: | JIA Jin-hua |
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| Abstract: | Taking the Kuqa continental foreland basin as an example,the key topics of the continental foreland basins have been discussed,such as the formation of the basin,depositional filling and sequence pattern,unconformity and sequence boundary,sequence constitution and models,source-reservoir-seal assemblages and lithostratigraphic traps.It is considered that the sequence of continental foreland basin is response to the tectogenesis of the margin.The foreland sequences are composed of lowstand systems tract,transgressive systems tract and highstand systems tract.Sequence boundary exhibits tectonic or depositional unconformity.Sequence boundary of the foreland basin frequently corresponds to a tectonic episode.Due to the flexible tectonic thrusting adjacent to the orogenic belt,the sequence pattern is response to different stages evolution of the basin.It is reflecting the interval change of the orogenesis from strong to weak.Sequence boundary of the foreland basin often represents the huge change of the depositional architecture.There are the lacustrine facies mudstones and gypseous mudstones of the tectonically stable below the sequence boundary.It developed very thick alluvial fan and fan-delta systems upon the sequence boundary,exhibiting the Molasse filling.There are different depositional fillings and stratigraphic patterns on the ambilateral sides of the foreland basin during the stage of tectonic activity and stability.There are major alluvial lowstand systems tracts adjacent to the orogenic belt during the tectonic activity.It is composed of very thick alluvial fan,fan-delta and braided delta systems.During the tectonic stability,there occurred transgressive systems tract,represented as mainly extensive river and lacustrine facies.The deposition thickness gradually decrease from the adjacent thrust belt to the basin.The matches of source-reservoir-seal assemblage of the continental foreland basin are good.The reservoirs are extensively distributed in the lowstand systems tract,transgressive systems tract and highstand systems tract.They were mostly deposited in braided delta and lacustrine shoreline enviornments.The lithostratigraphic traps mainly distributed in the foreslope area,including stratigraphic onlap unconformity traps and stratigraphic erosion unconformity traps along the margin of ancient bulge.They will become the new fields of petroleum exploration. |
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| Keywords: | continental foreland basin depositonal filling sequence stratigraphy Kuqa |
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