应用野外露头资料,通过选取与物源方向近于垂直观察剖面的精细描述、测量和分析,对鄂尔多斯盆地东缘延河、仕望河露头延长组典型的浅水三角洲沉积分流河道储层构型进行研究。研究结果表明:鄂尔多斯盆地延长组浅水三角洲分流河道按其分布位置和成因可分为主干分流河道(包括深切分流河道)、汊道和末端分流河道3种类型;除深切分流河道外,主干分流河道、汊道和末端分流河道砂体宽度、厚度呈正相关的双对数关系,相关系数高达0.97,即三者宽厚比相近,而深切分流河道宽厚比较小;其内部充填样式包括垂向加积充填和侧向加积充填2种,以垂向加积充填为主,且可进一步分为水平状、同心状和心滩—水道充填3种;分流河道存在侧向拼接—垂向切叠式、侧向拼接—垂向叠加式和孤立式3种复合叠置样式。
Based on the fine description, measurement and analysis of selected outcrop observation points, whose cross sections were nearly perpendicular to the source direction, the distributary channel reservoir architecture of lake basin was studied in the classic shallow-water delta sediments of the Yanchang Formation of Yanhe and Shiwanghe section in the eastern margin of Ordos Basin. The results show that according to the distribution and origin, distributary channels in shallow-water delta are divided into three types, including tnmk distributary channel which includes deeply incised distributary channel, inlet distributary channel and terminal distributary channel. Except deeply incised distributary channel, the relationship between width and thickness of other distributary channels is positively double-log with high correlation coefficient, up to 0.97. That is, the ratios of width and thickness of trunk distributary channel, inlet distributary channel and terminal distributary channel are similar and larger than those of the deeply incised distributary channel. There are two filling patterns of distributary channel, vertical and lateral accretion. And the predominant vertical accretion can be further divided into horizontal, concentric and bar-channel filling. There are three types of stacking patterns of distributary channel, lateral splicing-vertical.cutted, lateral splicing-vertical superposed and isolated pattern.