【摘要】 为了改进传统露头研究方法的不足,以及客观、全面地认识露头所揭示的地质信息,将激光雷达技术应用到露头地层成图研究中,并利用计算机技术实现地层图像可视化,形成了鄂尔多斯盆地上三叠统延长组杨家沟剖面数字露头。基于数字露头开展上三叠统延长组长3油层组层序地层、沉积旋回和砂体展布等地质信息的提取与分析,并利用典型层序界面识别标志,结合层序地层学理论,在数字露头上进行层序边界识别和层序界面追踪,划分出1个四级层序界面,其界面之下地层岩性表现为反旋回,界面之上地层岩性表现为正旋回,层序界面对应的位置砂体最厚。通过建立研究区沉积旋回的识别标志,在数字露头上进行沉积旋回界面的追踪与对比,识别出了3个不对称式短期旋回,这3个短期旋回又可组成1个四级基准面上升半旋回,为一套整体向上变细的四级准层序组,其砂体厚度向上具有减小的趋势。通过建立砂体解释标志,分别在四级基准面旋回底部和剖面顶部识别出了典型的河道砂体,进而对露头解剖的单砂体内部砂层进行了精细刻画与对比。总体认为,剖面岩性以细砂岩和粗粉砂岩为主,局部夹暗色泥岩和页岩;砂体侧向迁移,在垂向上呈多期叠置关系,横向上变化较大。更多还原

【Abstract】 In order to improve the shortcomings of the traditional method of outcrop research and cognize geological information more objectively and comprehensively from outcrop, the laser radar technique was applied to the study of outcrop stratigraphic mapping. With the use of computer visualization, this paper constructed digital outcrop of Yangjiagou section of the Upper Triassic Yanchang Formation, Ordos Basin. Geological information extraction and analysis were carried out based on digital outcrop, such as the sequence stratigraphy, sedimentary cycle and sand body distribution of Chang 3 oil reservoir set of Yanchang Formation. Through establishing typical sequence boundary identification marks and combining with the theory of sequence stratigraphy, sequence boundary identifying and tracking on digital outcrop were conducted and a fourth-order sequence boundary was identified. A positive cycle and a reverse cycle were respectively developed above and below the boundary, and the location of the thickest sand body is corresponding to the fourth-order sequence boundary. Through establishing sedimentary cycle identification marks, tracing and contrasting sedimentary cycle interface on digital outcrop, three asymmetric short-term cycles were identified. These three short-term cycles can compose a fourth-order base level rising half cycle. It is a set of the overall upward trend of the fourth-order parasequence-set, with the trend of decreasing thickness upward of sand body. Through the establishment of sand body interpretation marks, typical channel sand body were respectively identified at the bottom of the fourth-order base level cycle and the top of the profile. And then, fine description and comparison of the internal layer of single sand body was made according to the outcrop anatomy. Comparison results show that the main lithology of the profile is fine sand and coarse silt, locally clipping dark mudstone or shale.更多还原