准噶尔盆地腹部下侏罗统三工河组沉积体系

以岩心观察为基础,结合砂岩含量的变化及钻井、测井特征、地震反射等标志,总结了准噶尔盆地腹部侏罗系三工河组的沉积微相类型及相标志。指出,三工河组沉积时期砂体沉积微相的发育与分布主要受北东和北西方向物源体系的控制;由于不同沉积时期基准面与A/S比值的动态变化、物源体系特征及古地貌形态等的差异,导致了研究区东、西部沉积相类型及演化特征的差异;垂向上,沉积作用经历了由辫状河三角洲(扇三角洲)一曲流河三角洲一湖相的变化,其中三工河组中、晚期形成的三角洲前缘河口坝砂体和水下分支水道砂体是最重要的勘探目标。

Depositional System of Sangonghe Formation of Lower Jurassic in Hinterland of Junggar Basin

This paper reviews the microfacies' type and markers of Jurassic Sangonghe formation in hinterland of Junggar Basin based on core observation and combining with the variation of sand percentage as well as drilling/logging features and seismic reflection indicators, and points out that the growth and distribution of the sand microfacies in Sangonghe stage are controlled by the depositional sources form both northeast and northwest directions. The changes of datum level and A/S ratio and the diversity of depositional source systems and paleo-relief cause the differences in sedimentary facies type and evolution characteristics of eastern and western parts of the study area. Vertically, the sedimentary facies has undergone the changes from braided river delta (fan delta) to meandering river delta to lacustrine facies, among which the mouth bar sands at the delta front formed in middle and late Sangonghe stage and those of underwater distributary channel are the most important targets for exploration.