差异曲率下的曲流河点坝砂体定量表征——以黄河源区白河现代沉积为例

正确认识曲流河点坝砂体的形态和规模,对井间砂体连通认识、流体运移路径分析及剩余油高效精准挖潜具有重要意义。以黄河源区现代白河为例,利用ArcGIS软件对白河卫星影像的31个典型点坝砂体进行矢量化,建立点坝砂体规模参数的基础测量数据表,并通过坡降划分选取典型点坝曲流段进行刻画,在曲率划分的基础上探讨了点坝砂体规模与河道宽度的定量关系。结果表明:坡降越大,则河道宽度越小,曲率越小;点坝长度、点坝宽度与河道宽度两两之间呈正相关关系,且在不同曲率下,其相关性有所差异,当曲率k小于2时,点坝长度与河道宽度的相关系数为0.790,点坝宽度与点坝长度的相关系数为0.812,点坝宽度与河道宽度的相关系数为0.414;当k为2～2.5时,点坝长度与河道宽度的相关系数为0.709,点坝宽度与点坝长度的相关系数为0.883,点坝宽度与河道宽度的相关系数为0.841。该研究结果对曲流河储层定量表征具有一定的借鉴意义。

Quantitative characterization of point bar sand bodies in meandering river under different curvatures:A case study of modern deposition of Baihe river in the source area of Yellow River

A correct understanding of the shape and scale of meandering river point bar sand bodies is of great significance to the understanding of interwell sand body connectivity,fluid migration path analysis and efficient and accurate tapping of remaining oil. Taking the modern Baihe river in the Yellow River source area as an example, ArcGIS software was used to vectorize the 31 typical point bar sand bodies in the Baihe satellite image,and the basic measurement data table of the parameters of point bar sand body scale was established. The typical point bar meandering sections were selected for characterization through slope division,and the quantitative relationship between the scale of the point bar sand bodies and the width of the river channel was discussed on the basis of curvature division. The results show that the larger the slope,the smaller the river width and the smaller the curvature. There is a positive correlation among point bar length,point bar width and river channel width,and the correlation is different under different curvatures. When the curvature k is less than 2,the correlation coefficient between point bar length and river channel width is 0.790,the correlation coefficient between point bar width and point par length is 0.812,and the correlation coefficient between point bar width and river channel width is 0.414. When k is 2.0-2.5,the correlation coefficient between point bar length and river channel width is 0.709,the correlation coefficient between point bar width and point bar length is 0.883,and the correlation coefficient between point bar width and river channel width is 0.841. The research results can be used for reference to the quantitative characterization of meandering river reservoirs.