Prediction of channel connectivity and fluvial style in the flood basin successions of the Upper Permian Rangal Coal Measures (Queensland)

• Published in: AAPG Bulletin
• Main Authors: Stuart, J, Mountney, NP, McCaffrey, WD, Lang, S, Collinson, JD
• Format: Article in Journal/Newspaper
• Language: English
• Published: American Association of Petroleum Geologists 2014
• Subjects: Pollux; Queensland; ob river; Siberia
• Online Access: https://eprints.whiterose.ac.uk/82575/; https://eprints.whiterose.ac.uk/82575/1/2012_JS_SBlkwtr_Paper_Revised.pdf; https://doi.org/10.1306/06171312088

Predicting the presence and connectivity of reservoir-quality facies in otherwise mud-prone fluvial overbank successions is important because such sand bodies can potentially provide connectivity between larger neighboring sand bodies. This article addresses minor channelized fluvial elements (crevasse-splay and distributary channels) and attempts to predict the connectivity between such sand bodies in two interseam packages of the Upper Permian Rangal Coal Measures of northeastern Australia. Channel-body percent as measured in well logs was 2% in the upper (Aries-Castor) interseam and 17% in the lower (Castor-Pollux) interseam. Well spacing were too great to allow accurate correlation of channel bodies. The Ob River, Siberia, was used as a modern analog to supply planform geometric measurements of splay and distributary channels so that stochastic modeling of channel bodies was possible. The resulting models demonstrated that (1) channel-body connectivity is more uniform between minor distributary channels than between crevasse-splay channels; (2) relatively good connectivity is seen in proximal positions in splays but decreases distally from the source as channel elements diverge; and (3) connectivity tends to be greater down the axis of splays, with more isolated channel bodies occurring at the margins.