Stratigraphic and Reservoir Challenges with Triassic Plays in the North Sea

The North Sea (including west of Shetlands) is a structurally complex region located of the north to east margin of the UK and comprises offshore oil & gas fields within the territorial waters of five countries; UK, Norway, Denmark, Germany and The Netherlands. The subsurface of the North Sea is dominated with grabens. Extensional tectonics and failed rifting are fundamental to the distribution of oil and gas in the region and each graben is defined to capture regional differences in exploration history, geography, and geological evolution.

The Triassic play is one of the most under-explored plays in the North Sea which is expected to present substantial reservoir commodities that are economically viable. However, the Triassic plays are stratigraphically different across the North Sea across international boundaries. Despite the significant number of publications and unpublished reports on the North Sea, the Triassic plays in the North Sea (especially central graben) is an area of increasing interest to both industry and academic institutions. However, to date it has received relatively less attention. The Triassic Period is one of a few under-explored plays that has the potential to supply extensive resources with large commercial potential and research opportunities.

In particular, the Triassic Skagerrak Formation dominantly comprised of fluvial deposits and lacustrine sediments, containing packages of mudstones and sandstones with varying presence of evaporites. Several high-pressure high-temperature (HPHT) sections are present in the Central Graben and are typically related to high quality sandstone reservoirs that have become of high commercial interest.

Despite good reservoir quality and exploration of the sandstone packages within the Skagerrak Formation, the precise stratigraphic relationship between regions is complicated by the very nature of the palaeoenvironmental conditions in the Triassic. The region is structurally complex and understanding the connectivity of the sub-basins (pods) has been a specific point of interest for both the industrial and academic sectors. Traditional techniques such as biostratigraphy (i.e., palynology) is difficult in North Sea Triassic sediments due to impoverished recoveries or barrenness of microfossils. However, through a combination of two or more stratigraphic approaches such as, chemostratigraphy, isotope stratigraphy, sedimentary provenance, and core log analysis, a much better framework for correlation can be generated. Often these techniques are used independently and/or focus on a specific small area such as the Central Graben, leaving the results floating in terms of understanding the wider stratigraphy framework of the North Sea region.

The primary aim of this two-day virtual conference is to bring together the industrial and academic sectors to present and develop research strategies and targeted sites that will benefit both sectors in the future. The virtual conference will focus on current techniques, the challenges and future solutions in understanding and developing the Triassic reservoirs across the North Sea.

The main topics of the virtual conference will include:

• Integrated stratigraphic approaches & improved correlation
• UK-Norway inter-reservoir stratigraphic challenges
• Stable isotope stratigraphy of evaporites and mudstones
• Palaeogeography of the Triassic Central Graben
• Sedimentary sources, provenance as a factor controlling stratigraphy
• Structural geology of the Central Graben
• Facies analysis and interpretation – analogues with modern environmental settings
• Fluvial diagenesis and reservoir quality
• Drilling challenges in HPHT stratigraphic intervals
• Big data science, super computers and AI in improving stratigraphy
• Virtual core workshops