【摘要】 根据地面激光雷达、高精度差分GPS和高精度数码影像资料,制定数字露头野外数据采集方案,建立激光雷达点云数据拼接和坐标转换处理流程,提出基于最佳趋势面的三角网建模方法和数字露头表层模型优化方法。利用该方法,建立了鄂尔多斯盆地延长组谭家河露头的数字露头表层模型,在该模型的基础上开展了露头砂体展布与发育情况的分析,对识别出的三角洲平原分流河道砂体和三角洲前缘水下分流河道砂体进行了定量描述,前者单河道砂体垂向上呈孤立叠置样式,宽厚比小,后者单河道砂体垂向上呈多期连续叠置样式,宽厚比明显较大,进而对露头砂泥岩分布进行分析。该区砂体发育受沉积环境控制,分流河道以及水下分流河道砂体发育区砂地比明显较大,砂地比由小变大的方向为北东—南西向,与研究区物源方向基本一致。更多还原

【Abstract】 Combined with ground-based Lidar, high accuracy difference GPS and high precision digital image, this paper summarized field data acquisition scheme of digital outcrop, established the Lidar point cloud data splicing and coordinate conversion process, put forward triangular mesh modeling method based on optimal trend surface and optimization method of digital outcrop surface model. The surface modeling method of digital outcrop provides an effective basis for the outcrop fine quantitative study. Using this method, this paper established digital outcrop surface model of Tanjiahe outcrops of Yanchang Formation in Ordos Basin, and carried out outcrop sand body distribution and development analysis based on the digital outcrop model. Delta plain distributary channel sand body and delta front underwater distributary channel sand body were identified on the Tanjiahe digital outcrop model. The vertical overlap relationship of the former single channel sand body is isolated, and its width-thickness ratio is relatively small; the latter single channel sand body is multi period continuous stacking in the vertical direction, and its widththickness ratio is significantly larger. Analysis result of outcrop sandstone and mudstone distribution indicates that due to the development of sand bodies controlled by sedimentary environment, sand ratio of distributary channel and underwater distributary channel sand body development area was significantly larger. Sand ratio gradually increased from northeast to southwest, and it is basically consistent with the source direction of the study area.更多还原