Integrating
Digital Outcrop Data and Field Geology for Modelling
Multi-scale Heterogeneities in Complex Tidal Facies: Nukhul Half-graben,
Rarity, Frank1, David Hodgetts2,
Paul Wilson2, Rob Gawthorpe2 (1)
An integrated approach incorporating
digital outcrop surveying (LIDAR and GPS) and detailed field geology has been
used to model multi-scale 3D heterogeneities in tidal facies
of the Oligo-Miocene ‘rift initiation' succession, Nukhul Formation, Gulf of Suez. The continuous 3D exposure
at the Nukhul half-graben
provides an exceptional outcrop analogue for the complex facies
and sequence architecture of syn-tectonic tidal
reservoirs.
Modern ground-based LIDAR surveying
allows rapid collection of accurate and high resolution point cloud datasets.
The point cloud dataset provide a three dimensional, fully geo-referenced
framework into which detailed field observations and digitised
graphic sedimentary logs can be integrated using in-house software. Structural
and stratigraphic architecture can be accurately
measured directly from the point clouds and geostatistical
information on geological object sizes, shapes and orientations can be extracted.
High resolution digital photographs can be draped onto the point clouds to
create photorealistic models and used to delineate geological features and map
small-scale (cm to m) facies variations.
Tidal-related sedimentary heterogeneities
exist over a wide range of scales from pore structure (<1cm) to fault block
(>1km). Modelling these multi-scale
heterogeneities can help quantify reservoir uncertainty and mitigate geologic
risk. Conventional heterogeneity models are often purely statistically driven
with just a small amount of conditioning data. This study provides a highly
quantitative dataset which has been used to build ‘close to deterministic'
models from the outcrop data. These can be used to quantify and understand
small-scale lateral and vertical lithological, facies and petrophysical
variations, and identify sub-seismic boundary surfaces. The outcrop models can
also be used to quantify and minimise data loss
associated with the upscaling process.
AAPG Search and Discover Article #90063©2007 AAPG Annual Convention, Long Beach, California