构造-沉积格局控制下的砂体展布规律——以杭锦旗地区二叠系为例

The sand body distribution law controlled by tectonic-sedimentary pattern:a case study of Permian in Hangjinqi area

为了明确鄂尔多斯盆地北部杭锦旗地区二叠系砂体展布规律及构造-沉积格局对砂体展布的控制作用,文中对该区325个岩心样品的薄片鉴定、物性分析及阴极发光测试等资料进行了研究。结果表明:山2段—盒1段沉积期,盆地北部造山带的构造抬升使得物源区供给能力增强,砂岩成分成熟度明显降低,优质砂体主要发育在心滩相带;平面上,自北向南,沉积相由三角洲转变为冲积扇-辫状河复合沉积相,河道摆动频繁,形成了大面积网毯状砂体,垂向上,岩石组合由山2段的厚层泥岩夹薄层砂岩转变为盒1段的厚层砂岩夹薄层泥岩。

In order to study the Permian reservoir sand body distribution regulation and the controlling of tectonic-sedimentary pattern on sand body distribution in Hangjinqi of northern Ordos basin,the thin section identification,physical property and cathodoluminescence are tested and analyzed for 325 core samples in the study area.The results suggest that from Shan 2 Member to He 1 Member,the tectonic uplift of orogenic belt of the northern basin enhanced the supply capacity of the source area,and the reservoir sand debris component maturity decreased significantly.The high quality reservoir sand developed mostly in the channel bar deposition.In the plane,the sedimentary facies changed from delta deposition to alluvial fan-braided river composite deposition,and frequently swing of the channel formed a large area of net-blanket sand body.Vertically,the stratigraphic characteristics changed from thin sand layers within thick mud layers of Shan 2 Member to thin mud layers within thick sand layers of He 1 Member.