鄂尔多斯盆地南部延长组沉积特性与物源探讨

为了恢复鄂尔多斯盆地南部地区延长组的岩相古地理 ,寻找砂岩有利岩性储层区带 ,通过研究区内延长组沉积背景和长4 +5—长2 油层组的地球化学、岩石组分、沉积构造和层序演化规律等沉积特性 ,划分了三角洲沉积体系中的沉积相带类型及分布规律 ,指出了三角洲水下分流河道、河口坝相砂岩是有利的储集体 ,探讨了三角洲沉积体系有北东、北东东和西南三个主要物源方向以及发育机理 ,并对三个不同物源方向上形成的沉积砂岩的岩性组分、砂体分布等不同特征进行了对比和区别 .系统深入地探讨了三角洲沉积的发育机理

Depositional Feature and Material Source Analysis of Yanchang Group in Eerduosi Basin

The depositional background of Yanchang group and the depositional feature of Chang4+5～chang2 series strata were studied in order to reappear its paleogeophic lithofacies map and seek favorable oil and gas accumulation zones.The depositional feature incluses geochemistry, rock composition, sedmentary structure and sequence evolution law. The types and distribution law of the depositional facies in the deltaic sedimentary system were classified. It is held that distributary channel and distributary mouth bar sandstone are favorable oil reservoir bodies, and three main material souree directions are in NE, NEE and WS. The lithological combination and sandbody distribution in the three directions were compared. The development mechanism of the deltaic deposition was also studied.