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The Taranaki Basin, located offshore New Zealand, is a Cretaceous rift basin which has well defined yet complex Miocene deepwater sedimentary systems. This paper analyzes a pronounced anomalous seismic response in a late Miocene to early Pliocene deepwater channel within the 2005 Hector 3D survey located in the southern Taranaki Basin. Several seismic attributes were calculated to interpret the extent of these anomalous features. Modern analogues from Snedden (2013) within both the Iron River reservoir in Albania, Canada and the East Breaks Basin Four, offshore Gulf of Mexico suggest that these anomalous seismic features are most likely channel-body basal scours resulting from turbulent flows that eroded the base of the channel. One alternative interpretation is that this is not a channel but rather a scar left behind from a small-scale mass trasnport deposit (MTD) where sediment later ponded and filled in the rugose topography left by the MTD. This process has also been observed by Kremer et al. (2018) within the Molasse Basin in southern Germany. However, these scours could also be interpreted as pockmarks resulting from channel abandonment and fluid escape due to compaction. Jobe et al. (2011) described this process within submarine canyon systems, offshore Equatorial Guinea. Within all possible interpretations, there is evidence of differential compaction as sediment fills the accommodation space and creates a concave down expression immediately above the interpreted scours.

An effective method of identifying and discriminating undersaturated gas accumulations remains unresolved, resulting in uncertainty in hydrocarbon exploration. To address this problem, an unsupervised machine learning multi-attribute analysis is performed on 3D post-stack seismic data over several blocks within the deepwater Gulf of Mexico and within the Carnarvon Basin, offshore Australia. Results reveal that low-saturation gas (LSG) reservoirs can be discriminated from high-saturation gas (HSG) reservoirs by using a combination of instantaneous attributes that are sensitive to small amplitude, frequency, and phase anomalies with self-organizing maps (SOMs). This methodology shows promise for de-risking prospects, even if it is not quantitative, particularly in frontier and exploration basins where wells may not exist or be very limited. However, this method only proved to be successful within the Gulf of Mexico and yielded limited results in the Carnarvon Basin. This difference is most likely due to the Carnarvon Basin having a different amplitude response resulting from a different burial history and fluid saturations when compared to the Gulf of Mexico. Therefore, this method is non-transferrable, and a different combination of attributes may be needed in other LSG-prone basins.

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