Predicting plays in the former disputed zone of the Barents Sea – the value of sequence stratigraphy.

Abstract

Following the maritime delimitation of the former disputed zone of the Barents Sea in 2011 the region is set to become accessible for petroleum exploration in 2014 as part of the 23rd licencing round. This underexplored south-eastern sector of the Norwegian Barents Sea is likely to play a key role in the future of Norwegian offshore petroleum exploration, with a possible 300 million Sm3 oil equivalent recoverable resources in this region (NPD, 2013), yet geological data, and hence understanding, in the region are limited. Here we show how using a comprehensive data set for the Barents as a whole, within a sequence stratigraphic and geodynamic framework for the wider Arctic region, provides insight into the likely play elements of the South East Barents Sea.

The Barents Sea was affected by three major tectonic phases, the Late Silurian Caledonian Orogeny, the Late Paleozoic-Mesozoic Uralian Orogeny and structural changes associated with break-up and rifting of the Eurasia Basin and the Norwegian Seaway. The likely impact of these events upon the South East Barents Sea lithostratigraphy and play elements will be assessed. As an example, Triassic sediments derived from the Uralian Orogeny prograded across the Barents Sea as a series of north-westerly dipping clinoforms clearly visible in both seismic and well data. The transgressive regressive cycles within this package of sediments can be correlated regionally. Analysis of geochemical data shows a correlation of organic-rich units, with the potential to act as source rocks, with transgressive and maximum flooding intervals. Using this framework we are also able to predict where coarse clastic reservoir targets are likely to interfinger with these potential source rocks during intervening lowstands.

The sequence stratigraphic and geodynamic framework also provides insights into Palaeozoic plays similar to that recently highlighted by the Gohta discovery on the southern flank of the Loppa High. The reservoir target comprises a series of predominantly tropical carbonate facies which evolved into a series of cool water carbonates with periodic karst development. Similar karst horizons within the equivalent of the Gohta carbonates can be predicted during the Permo-Carboniferous across the Barents Sea during regionally significant lowstand intervals. We will evaluate a range of play elements including Devonian-Carboniferous syn-rift and early post-rift successions, Permian carbonates, Triassic transgressive-regressive systems and Jurassic clastics.

AAPG Datapages/Search and Discovery Article #90192 © 2014 European Regional Conference and Exhibition, Barcelona, Spain, May 13-15, 2014