PS3-D Geological Model Building Using Remotely Sensed Satellite Data*
By
Mike Oehlers1 and Pedro Barreto1
Search and Discovery Article #40218 (2006)
Posted October 9, 2006
*Adapted from poster presentation at AAPG Annual Convention, Houston, Texas, April 9-12, 2006
Click to view posters in PDF format.
Poster 1 (~2.7 mb) Poster 2 (~3.6 mb) Poster 3 (~4.1 mb)
1NPA Group, Edenbridge, United Kingdom ([email protected])
Abstract
Recent availability of high resolution Digital Elevation Models from the SRTM mission and from SPOT Image have provided geologists with regional (90m resolution) and licence-specific (20m resolution) data sets that allow construction of 3-D models to aid hydrocarbon exploration.
At a basic level, the DEMs are used to provide good
regional and detailed perspective views of structurally complex localities using
imagery or geological data draped over wire-frame models derived from DEMs. The
visualisations can then be “flown through,” allowing virtual field trips to
demonstrate particular structural
style.
The next phase allows for extraction of dip values by
relating dipping “flat irons” to slope values. Isolating true dipping surfaces
and calculating dips by displaying the DEM as a slope and slope azimuth map
provides structural
control over large areas for a fraction of the cost of
mobilising field teams in often inaccessible or hostile terrain. Using this dip
data, topographic profiles are extracted from the DEM and are used with geology
derived from satellite-based mapping as the basis of 2-D
cross
section
generation, as in examples from the Zagros Mountains shown here.
In the 3-D domain, it is possible to define
stratigraphic boundaries from multispectral satellite imagery and then tie the
contacts to the DEM and produce a grid of elevations for a particular
stratigraphic surface. These are then input into a gridding program to produce
structural
contour
maps
of important intervals near the surface, or, by means of
extrapolation, deeper levels. This technique is illustrated by examples from
Yemen.