库车坳陷白垩系储层的形成环境及成因分析  

ANALYSES FOR THE SEDIMENTARY ENVIRONMENT OF CRETACEOUS STRATA AND IT'S CAUSES OF FORMATION IN THE KUQA DEPRESSION

作　　者：刘建清[1] 赖兴运[1] 于炳松[1] 

机构地区：[1]中国地质大学地球科学与资源学院,北京100083

出　　处：《现代地质》2004年第2期249-255,共7页Geoscience

基　　金：国家"九七三"项目 (2 0 0 1CB2 0 910 4)。

摘　　要：近年来 ,在中国新疆库车前陆盆地中发现了克拉 2等大型、特大型气田 ,并显示出良好的油气勘探前景。白垩系巴什基奇克、巴西盖组地层是克拉 2等气田的主力储层 ,研究其成因并建立科学合理的预测机制具有重大的理论和现实意义。在对库车盆地的构造背景、沉积物质来源、岩石结构特征、古生物、微量元素地球化学特征、粒度分析、沉积构造、沉积体系等多侧面进行综合研究的基础上 ,认为该区在下白垩系储层沉积时处于干旱氧化的古气候环境 ,储层岩石具低成分成熟度和结构成熟度的特征 ,储层自下而上具典型的沉积构造和完整的沉积序列 ,应属扇三角洲—辫状河三角洲—湖泊沉积体系。特别是粒度资料分析表明该区的储层多呈一个过渡性的特征 ,它既不同于典型的浊流 ,又不同于典型的曲流河特征 ,形成了该区以辫状河为主的显著沉积特点。In recent years, large-scale gas fields have been found in the Kala 2 area of the Kuqa depression, and show well prospects in gas and oil exploration. Basjqke Formation and Baxgai Formation are the main reservoirs. The researches for the causes of their formation can establish scientific predicting system; therefore have a profound significance. Based on the analyses of tectonic, the source of the deposits, the microstructure of the sandstone, the palaeontological species, the trace elements, the granularmetric character, the sedimentary structure and system, we can see that the strata are under arid-oxidizing climate during their formation, that the lithology of the reservoirs show a low-grade compositional maturity and structural maturity character, that the strata are a typical sedimentary structure and sedimentary sequence from bottom to top. It is concluded that the Cretaceous strata should be included in a braided delta, meandering river and lacustrine sedimentary system. One of the most important characters in Upper Cretaceous strata is that granularmetric character shows a transitional peculiarity, which is not only different to fluvial sediment, but also different to alluvial fan, all of which constitute a manifest character of the Cretaceous strata.

关 键 词：库车坳陷 白垩系 扇三角洲 辫状河三角洲 

分 类 号：P539.2[天文地球—古生物学与地层学]