3D seismic interpretation of the depositional morphology of the Middle to Late Triassic fluvial system in Eastern Hammerfest Basin, Barents Sea

The Patchawarra Formation is characterised by Permian aged fluvial sediments. The conventional hydrocarbon play lies within fluvial sandstones, attributed to point bar deposits and splays, that are typically overlain by floodbank deposits of shales, mudstones and coals. The nature of the deposition of these sands has resulted in the discovery of stratigraphic traps across the Western Flank of the Cooper Basin, South Australia. Various seismic techniques are being used to search for and identify these traps. High seismic reflectivity of the coals with the low reflectivity of the relatively thin sands, often below seismic resolution, masks a reservoir response. These factors, combined with complex geometry of these reservoirs, prove a difficult play to image and interpret. Standard seismic interpretation has proven challenging when attempting to map fluvial sands. Active project examples within a 196 km2 3D seismic survey detail an evolving seismic interpretation methodology, which is being used to improve the delineation of potential stratigraphic traps. This involves an integration of seismic processing, package mapping, seismic attributes and imaging techniques. The integrated seismic interpretation methodology has proven to be a successful approach in the discovery of stratigraphic and structural-stratigraphic combination traps in parts of the Cooper Basin and is being used to extend the play northwards into the 3D seismic area discussed.

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An improved regional structural model of the Upper Carboniferous of the Cleaver Bank High based on 3D seismic interpretation

Geological Society London Special Publications ◽

10.1144/gsl.sp.2003.212.01.03 ◽

2003 ◽

Vol 212 (1) ◽

pp. 23-37 ◽

Cited By ~ 7

Author(s):

B. M. Schroot ◽

H. B. De Haan

Keyword(s):

Structural Model ◽

Seismic Interpretation ◽

3D Seismic ◽

Upper Carboniferous

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Global carbon isotope signal in the Middle Triassic on Svalbard

10.5194/egusphere-egu21-15701 ◽

2021 ◽

Author(s):

Victoria S. Engelschiøn ◽

Øyvind Hammer ◽

Fredrik Wesenlund ◽

Jørn H. Hurum ◽

Atle Mørk

Keyword(s):

Carbon Isotope ◽

Depositional Environment ◽

Middle Triassic ◽

Barents Sea ◽

Water Productivity ◽

Sedimentary Environment ◽

The Arctic ◽

Late Triassic ◽

Triassic Boundary ◽

Thin Sections

Several carbon isotope curves were recently published for the Early and Middle Triassic in Tethys. Recent work has also been done on the Early Triassic of Svalbard, but not yet for the Middle Triassic. This work is the first to measure &#948;13C for different Middle Triassic localities on Svalbard, which was then part of the Boreal Ocean on northern Pangea. Our aim is to understand the controls on the Svalbard carbon isotope curve and to place them in a global setting.Correlating Triassic rocks around the world is interesting for several reasons. The Triassic Period was a tumultuous time for life, and the Arctic archipelago of Svalbard has shown to be an important locality to understand the early radiation of marine vertebrates in the Triassic. Much effort is also made to understand the development of the Barents Sea through Svalbard&#8217;s geology.Carbon isotope curves are controlled by depositional environment and global fluctuations. Global factors such as the carbon cycle control the long-term carbon isotopic compositions, while short-term fluctuations may reflect the origin of organic materials in the sediment (e.g. algal or terrestrial matter), stratification of the water column, and/or surface water productivity. Carbon isotopes can therefore be useful to understand the depositional environment and to correlate time-equivalent rocks globally.The dataset was collected through three seasons of fieldwork in Svalbard with localities from the islands Spitsbergen, Edge&#248;ya and Bj&#248;rn&#248;ya. Detailed stratigraphic sampling has resulted in high-resolution &#948;13C curves. These show three strong transitions; 1) on the boundary between the Early and Middle Triassic, 2) in the middle of the formation and 3) at the Middle and Late Triassic boundary. Several Tethyan localities show a possibly similar Early-Middle Triassic signal. Current work in progress is sedimentological analysis by thin sections and X-ray fluorescence spectroscopy (XRF) to further understand the sedimentary environment.

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