准噶尔盆地克百断裂下盘二叠系砂砾岩的沉积模式

为建立准噶尔盆地西北缘克百断裂下盘二叠系砂砾岩的沉积模式,以为优质储层的预测提供借鉴,通过岩心观察、薄片分析及扫描电镜分析,结合录井资料和测井资料,在宏观构造背景和沉积环境下,对研究区砂砾岩的沉积特征进行了研究。结果显示,研究区砂砾岩沉积环境分为水上和水下两种,总体上补给水体主河道的水量较大,水流稳定、不间断;砂砾岩储层的物性随着沉积环境的不同表现出较大的差异,且以扇三角洲前缘亚相水下分流河道微相最好。强调了湖岸线对储层物性的控制作用,模糊了冲积扇扇缘与扇三角洲平原之间的界线,将冲积扇与扇三角洲有机结合,提出了研究区冲积扇-扇三角洲-湖泊相相结合的沉积模式,把研究区划分为3个沉积相、8个沉积亚相。

Sedimentary model of the Permian sandy conglomerate in the footwall of the Kebai Fault, the Junggar Basin

This paper aims at developing a sedimentary model of the Permian sandy conglomerate in the footwall of the Kebai Fault in the Junggar Basin,which can provide a reference for predicting good reservoirs.Sedimentary features of the sandy conglomerate in the study area are examined through core observation,thin section analysis and scanning electron microscope analysis.Tectonic settings and depositional conditions are taken into consideration and logging data are also consulted.The depositional environments of the sandy conglomerate in the study area can be divided into two types,namely above-water and underwater environments.Overall,the main feeder channels are large in water volume,and stable and continuous in water flow.Physical properties of the sandy conglomerate reservoirs differ greatly in different depositional environments,and the best occurs in underwater distributary channel on fan delta front.The control of shoreline on reservoir physical property is highlighted,while the distinction between alluvial fan margin and fan delta plain is obscured.A sedimentary model with alluvial fan-fan delta-lacustrine facies integrated is proposed and 3 sedimentary facies and 8 sedimentary subfacies are identified in the study area.