Pickel, Alexandra; Frechette, Jedediah; Weissmann, Gary
For the past two decades, subsurface heterogeneity studies have focused on modeling sedimentary structure and facies distributions using a variety of geostatistical approaches; however, due to limitations in parameterization data and dimensionality these approaches may not capture realistic facies geometries and subsequent fluid flow paths. Vertical variability is often observed at high resolution, as in core and geophysical well logs, however lateral heterogeneity is difficult to capture and as a result, a high amount of uncertainty exists in subsurface flow models. In an attempt to more accurately characterize subsurface reservoirs, a quantitative outcrop analog-based approach utilizing terrestrial lidar and high-resolution, calibrated digital photography is combined with lithofacies analysis.
In the summer of 2011, terrestrial lidar scans and high resolution digital imagery of approximately 15,000 m2 of contiguous cliff face were acquired of a Westwater Canyon Member, Morrison Formation outcrop in Ojito Wilderness, New Mexico, USA. The resulting 3-D lidar point cloud, ~ 400 points/m2, was used to develop a mesh with ~ 2.5 cm resolution. The digital images were processed through a series of photogrammetric techniques including edge detection and textural filters to delineate different facies and sedimentary structures. The resulting classified images were projected onto the high-resolution mesh creating a highly realistic digital outcrop model. Architectural element analysis of the outcrop showed correlation of the major bounding surfaces, i.e. 5th order, across the study area. These surfaces, in combination with the image analysis results, were used to define depositional and modeling units. The digital outcrop was used to quantify the geometries and spatial distribution of these units. This data was used to interpolate a volume for and parameterize a geocellular model.
AAPG Search and Discovery Article #90163©2013AAPG 2013 Annual Convention and Exhibition, Pittsburgh, Pennsylvania, May 19-22, 2013