鄂尔多斯盆地三叠系延长组层序地层特征

Sequence-stratigraphic features of Yanchang Formation ,Triassic system in Ordos Basin

根据Fischer图解、层序结构分析以及高分辨率层序地层理论。鄂尔多斯盆地中生界三叠系延长组（T3y）以长7为界，可以划分为一个二级层序（超长期旋回）和五个三级层序（长期旋回SQ1-SQ5）；根据层序特征及沉积特征将延长组划分五套成藏组合、两类复合式储层，分别为A型复合式储层和B型复合式储层；通过镇43井-庄9井重点解剖，发现延长组长8油层组符合典型的Ⅰ型层序剖面结构特征；以层序划分编制砂体厚度图，可以更加清楚地反映出砂体形态和三角洲沉积体系。综合研究结果表明．层序地层研究结果对于全面认识延长组成藏组合，预测新层系和新的勘探目标具有显著效果。该项研究具有广阔的应用前景。

Using Fischer Illustration ,sequence structure analysis and high resolution sequence stratigraphy theory, Yanchang Formation can be separated as one second-order sequence and five third-order sequence （SQ 1-SQS）. According to sequence and sedimentary features,Yanchang Formation contained five hydrocarbon accumulation assemblages and two kind of composite reservoirs--A-type composite reservoir and B-type composite reservoir.It is find that the sequence section of Zhen43 Well-Zhuang9 Well have the attribution of 1-type sequence stratigraphy featuers.According to sequence features mapping ,the sandstone isopach map can more clearly reflect the sandstone shape and plot sedimentary systems.It is concluded that the sequence method is more effective way to predict hydrocarbon accumulation assemblage,new oil beds and new exploration targets.