西峰油田延长组长8油组砂体高分辨率层序等时对比分析

Isochronic correlation of sandbodies with Chang 8 oil formation by high resolution sequence analysis in Yanchang Formation,Xifeng oil field, Ordos Basin,China

以高分辨率层序地层学理论和技术方法为指导,通过钻井、测井资料的综合研究,在详细分析鄂尔多斯盆地西峰油田延长组长8油组短期、中期基准面旋回发育特征的基础上,以短期层序作为等时地层对比单元建立了长8油组的高分辨率时间-地层格架。在此基础上,应用“基于基准面旋回分析和高分辨率地层格架的砂体等时追踪对比技术”,分析认为西峰油田长8油组砂体的等时对比模式有“等高程、非同期和异成因”和“非等高程、同期、异或同成因”两种。形成于快速湖进期的西峰油田长8油组厚层砂体,受控于基准面旋回的升降,是由不断向陆方向退缩、多种沉积微相砂体复合叠加形成的。

On the basis of a comprehensive study of the core and log data, taking the high-resolution sequence stratigraphic theory as a direction, the authors carefully analyse the development features of short- and middle term base-level cycles of Chang 8 oil formation in the Xifeng oil field of Ordos Basin and build high-resolution age-strtigraphic framework. By using the isochronic tracking correlation technique of base-level cycle analysis and high-resolution strtigraphic framework, two types of isochronic sandbody correlation model of both ＂equielevation, nonsynchrone, hetero-origin＂ and ＂unequal-elevation, synchrone, identical genesis＂ are supposed in Chang 8 oil formation of the Xifeng oil field. The upping and downing of base-level cycles control the thick sandbodies of Chang 8 oil formation which deposited during quickly lacustrine transgression. The sandbodies can be divided into many types of microfacies and continuously regressive toward land.