姬塬地区长6油层组进积型三角洲识别及古地理演化

The Recognition of Prograded Delta and Palaeogeographic Evolution of 6^(th) Member of Yanchang Formation in Jiyuan Area of Ordos Basin

以岩心和测井资料为基础,对姬塬地区长6油层组砂岩的岩石结构、沉积构造、粒度分布特征、古生物特征等相标志进行详细的研究,认为长6油层组发育三角洲相,并以三角洲前缘亚相为主,水下分流河道砂体发育,河口坝不太发育。并分析长6油层组各亚期沉积微相的平面展布,自长63油层至长61油层沉积期,三角洲沉积范围不断扩大,主河道逐渐发育,砂体分布范围逐渐扩大,属进积型三角洲沉积,平面上形成大规模复合连片砂体,是石油聚集的重要条件之一。

The facies markers of rock structure,sedimentary structure,grain size distributive characteristics and biological characteristics of the 6th member of Yanchang Formation in Jiyuan Area were studied in detail.On the basis of core and logging data.It was considered that delta was developed,and it was mainly delta front subfacies,while underwater distributary channel sand body developed well with little mouth bar.The sedimentary microfacies distribution during sub-stage of 6th Member is analyzed,from the periods of Chang 63 to 61,the delta depositional extent has been expanded gradually,the main stream channel has been gradually developed and sand body distribution has been expanded gradually,it belongs to prograding delta deposition.On the plane,a large-scale.