Mega-Merged LIDAR Surveys: Quantitative Analysis of Stratigraphic and Structural Systems at the Basin Scale

Rob Gawthorpe, David Hodgetts, Frank Rarity, and Paul Wilson
University of Manchester, Manchester, United Kingdom

High resolution 3D laser scanning (LIDAR) and Differential Global Positioning Systems (DGPS) are now established technologies for quantitative outcrop analysis. Most LIDAR-based studies, however, have focused on relatively small study areas. We use an example of a mega-merged LIDAR dataset comprising 64 separate survey stations comprising over 1 billion data points with a typical spacing of 5 cm, to quantify basin-scale facies and thickness distributions in three-dimensions continuously from centimetre- to kilometres-scales. This point cloud is co-registered with high-resolution digital colour images. The examples used in this presentation come from an exceptionally well exposed, half graben basin located in the hangingwall of the 11 km long Nukhul Fault, Suez Rift, Egypt. The concept of mega-merged LIDAR surveys has parallels to merged regional 3D seismic datasets, and bridges the gap between the seismic and reservoir modelling scales. The Nukhul dataset allows detailed quantitative analysis of large-scale, 100 m high x 5 km long, cliff faces that are inaccessible in the field, and highlights subtle controls on early syn-rift facies distributions. The dataset also provides high-resolution data, at the bed-scale, on the heterogeneity within tidal channel and tidal flat deposits down that comprise the main stratigraphic elements of the Nukhul Formation. Although data collection and merging surveys is routine, visualizing and interpreting the mega-merged datasets in real-time is more problematic, requiring high performance graphical processing.