鄂尔多斯盆地姬塬地区上三叠统坡折带、斜坡类型与油藏的关系

通过盆地边界性质、沉积相类型、地层厚度、沉积序列与砂体空间组合特征及砂岩的粒度变化与物性的研究，结合地震相对姬塬地区上三叠统延长组长4+5—长7油层组湖盆古地貌的恢复结果，认为鄂尔多斯盆地西北缘、西缘、西南缘、东南缘的沉积边界受构造控制，属于构造坡折带，形成以冲积扇、扇三角洲、辫状河三角洲共同发育的沉积格局；盆地东北缘和北缘为扰曲宽缓盆地边缘性质，属于沉积坡折带，发育缓坡曲流河三角洲沉积体系。姬塬地区三角洲前缘可划分为坡型前缘和台型前缘两种斜坡带类型。位于坡型前缘的砂体厚度大、物性好，是低渗背景上相对高渗带发育区，为油藏聚集的有利场所。该成果为在大型坳陷型盆地中寻找三角洲相隐蔽油气藏提供了新的研究思路与勘探方向。

Relationship of Slope-Break,Slope Type with Hydrocarbon Pool-Forming of the Upper Triassic from Jiyuan Area,the Northwestern Ordos Basin

The northwestern,western,southern and southeastern depositional margin of the Ordos basin is tectonic slope-break controlled by tectonic movement occurred at the end of the Triassic,where alluvial,fan-deltaic and braided-deltaic sedimentary suite developed.While the eastern and northeastern margin belong to depositional slope-break because of its gently uplifting during the late Triassic,which resulted in the meandering-deltaic sedimentary system.Two types of slopes including slope-shaped-front and platform...