Integrating Digital Outcrop Data and Field Geology for Modelling Multi-scale Heterogeneities in Complex Tidal Facies: Nukhul Half-graben, Gulf of Suez, Egypt

Rarity, Frank¹, David Hodgetts², Paul Wilson², Rob Gawthorpe² (1) University of Manchester, Manchester, United Kingdom (2) University of Manchester, Manchester, England

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.