--> Abstract: Photogeological and Image Analysis Techniques for the Development of Quantitative, High-resolution Sequence Stratigraphic Models, by J. J. M. Lewis, M. J. Arnot, T. R. Good, and R. Pelling; #90987 (1993).

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LEWIS, JONATHAN J. M., MALCOLM J. ARNOT, TIMOTHY R. GOOD, and RICHARD PELLING, Department of Petroleum Engineering, Heriot-Watt University, Edinburgh, Scotland, UK

ABSTRACT: Photogeological and Image Analysis Techniques for the Development of Quantitative, High-resolution Sequence Stratigraphic Models

Photogeological techniques have long been used to record geometrical relationships at outcrop, but in outcrop based reservoir characterization studies their application has remained semiquantitative. A methodology has been developed for the rapid collection and analysis of quantitative 3-D stratigraphic data for stochastic reservoir modelling. The technique uses helicopter based camera systems and conventional image processing techniques.

For photographic data to be quantitative and same-scale, imagery must be collected from vertical cliff faces within the plane of a major stratigraphic or sedimentological bounding surface and at a constant distance from the outcrop. To achieve this, photographic imagery is acquired using a medium format camera at regular intervals along cliff faces and at a constant distance measured by a laser range finder. Long focal length lenses on medium format cameras can obtain < 2% scale change across the central 60% of images. Overlapping adjacent images enables large photo panels to be developed with resolution sufficient for mapping of sequence to lamina scale features.

To extract stratigraphic data, images are scanned, and bounding surfaces digitized on screen. Elements within the resulting stratigraphic template are assigned different grayscale values. These classified images can subsequently undergo rapid and accurate quantification of parameters such as area, aspect ratio and percentage occurrence, using a standard image analysis package.

Comparisons of the spatial statistics derived using this new methodology with more conventional ground based 35 millimeter photography illustrate different probability distribution functions for the same geological patterns. These can lead to significantly different stochastic reservoir models, especially in channelized fluvial reservoirs.

AAPG Search and Discovery Article #90987©1993 AAPG Annual Convention, New Orleans, Louisiana, April 25-28, 1993.