准噶尔盆地侏罗系沉积体系纲要

Depositional System Frameworks of the Jurassic in Junggar Basin

侏罗系为准噶尔盆地重要的含油气层系,其层序发育较完整,沉积相类型丰富,沉积体系多样。露头、钻测井、地震三位一体研究表明,侏罗系发育七个三级层序,其沉积相类型包括冲积扇、河流、三角洲、扇三角洲、湖泊和沼泽等。这些沉积相在各层序体系域内呈有序排列。各期物源及岩相古地理分析表明,准噶尔盆地侏罗纪发育八套沉积体系,即克拉美丽山前冲积扇-辫状河-曲流河-三角洲-湖泊沉积体系、乌伦古扇三角洲—湖泊沉积体系、德伦山前辫状河-曲流河-三角洲-湖泊沉积体系、哈拉阿拉特山前冲积扇-辫状河-三角洲-湖泊体系、车拐冲积扇-辫状河-三角洲-湖泊沉积体系、四棵树曲流河—三角洲-湖泊沉积体系、伊林黑比尔根山前冲积扇-辫状河-三角洲-湖泊沉积体系、博格达山前曲流河-三角洲-湖泊沉积体系。其中克拉美丽沉积体系的发育最具有继承性。这些沉积体系的展布在总体上控制了盆地内部油气有利储集层的发育。

The Jurassic is one of significant oil-bearing strata quences, various sedimentary facies and diversiform depositional in Junggar basin with relatively well-reserved sesystems. Based on outcrop profiles, well data, logging data and seismic data, the Jurassic can be divided into seven sequences consisted of alluvial fan, stream, delta, fan delta, lacustrine and swamp facies which assemblaged in the tracts orderly. Research on provenance and lithofacies paleogeography indicates that there were eight sedimentary systems in the Jurassic in the Juggar basin, i. e. , alluvial fan-braided stream-meandering stream-delta-lacustrine depositional system off Kalamay Mountains, delta fan-lacustrine depositional system in Wulungu, braided stream-meandering stream-delta-lacustrine depositional system off Delun Mountains, alluvial fan-braided stream-delta-lacustrine depositional system off Halaalate Mountains, alluvial fan-braided stream-delta-lacustrine depositional system in Cheguai, meandering stream-delta-lacustrine depositional system off Sikeshu Mountains, alluvial fan-braided stream-delta-lacustrine depositional system off Yilinhebier Mountains, meandering stream-delta-lacustrine depositional system off Bogeda Mountains. Among the eight depositional systems the depositional system off Kalamay Mountains was well developed in some sequences. These depositional systems controlled the favorable reservoir development of the Jurassic in Juggar Basin.