Barents Sea Tectonic Basin Modelling (BarMod) with focus on potential petroleum systems in the Central Barents Sea Region

BarMod continues our long-term focus on the Barents Sea structure and geological evolution. At the same time it contributes to further develop our research collaboration with Russia. In previous projects we have established good collaboration with Russian colleagues on key regional geological tasks, however at the same time we had to avoid bringing up details about sensitive information regarding the former disputed area in the central Barents Sea. Since the border between Norway and Russia was settled, we can focus on the exiting area of the central Barents Sea on both sides of the border line. To understand this area we have to approach it from both sides based on both geological and geophysical data. Sometimes the key to understanding the structuring in the central Barents Sea lies on the Russian side, other times it lies in the west on the Norwegian side. The starting point for BarMod was therefore, together with Russian partners, to build a joint geological/geophysical database that we can use to improve our understanding of the formation and evolution of sedimentary basins in the Barents Sea. A key element of BarMod was to carry out quantitative basin analysis, and the numerical modeling was led by an experienced postdoc who had previously published several modeling papers on the Barents Sea. Through this we obtain better understanding of fundamental geological processes, and at the same time we shed light on key factors relevant for petroleum exploration. The project is thus both basic and applied research at the same time. Already in the previous PETROBAR project we began to look closer at alternative processes that could have played an important role in the Barents Sea basin development. In BarMod we have taken this further using a quantitative approach, and at the same time we have studied how petroleum systems have been affected by these processes. This provides new and important information about when petroleum is generated and migrated to potential traps. At the same time we can better determine when the traps formed. We are not exploring for petroleum directly, but our knowledge can be useful for the companies doing petroleum exploration. We contribute with knowledge on deep structures and processes that affects the vertical motion and temperature histories of the basins. Furthermore, we establish regional geological knowledge that is important for understanding the driving force(s) for the basin development and how depositional systems are affected by these. This knowledge can be used by the geologists in the companies to reduce the exploration risk. The PhD fellow in BarMod has focused on the Norwegian side of the central Barents Sea, and in particular on detailed analysis of seismic (2D and 3D) data where this has become available. Large areas around the Hoop Fault Complex are covered by 3D seismic and recent findings have been made. In BarMod we have focused on the structural evolution of this area. Through this study we identified deep rift structures that are partly filled with evaporates. We have mapped these in detail over large areas in southern parts of the Norwegian Barents Sea, and identified structural elements and mechanisms that are important to understand in the ongoing licensing round. Basins primarily formed by extension have later been affected by compression, forming many of the structural traps the companies now study in detail. We can help with knowledge about when, why and how these structures formed, which can be of crucial importance for their prospects and exploration models. To improve the understanding of the processes we study we have to look deeper, beneath the basins in the crust and upper mantel. In BarMod we have therefore collaborated closely with a project where GFZ Potsdam and University of Oslo have further developed a 3D for the whole lithosphere (basin, crust and upper mantel) which covers the wider Barents-Kara Sea area. Knowledge based on this model can be used to constrain key parameters in our quantitative models for basin formation and evolution (e.g. temperature, strength).

The Barents Sea is both geologically and geopolitically divided into western and eastern regions. Until recently, research and data acquisition in the Central Barents Sea has been limited due to the disputed area between Norway and Russia. Because of this , the transition between the wide sag basins of the east and the narrow rift basins of the west is poorly understood. The recent agreement between Norway and Russia concerning the borderline opens new opportunities with respect to research, mutual compete nce building and petroleum exploration. Waiting for new data covering the former disputed area, we can initiate new research activities by integrating Norwegian and Russian knowledge and data across the Central Barents Sea. Some relevant data already exi st that will increase our understanding of the proposed study area. Large structures/prospects are evident, but there are many uncertainties (high exploration risk) related to evaluations of the petroleum systems, e.g. source rocks (distribution and matur ation), reservoir rocks (distribution and quality), structural evolution, and effects of the late uplift and erosion. We propose to model several intersecting W-E and N-S regional 2D profiles capturing the major provinces of the entire Barents Sea shelf, with particular focus on the transitional domain in the central Barents Sea. Two distinctly different methods (forward modelling and backstripping) will be applied and developed in the tectonic basin modelling. This integrated approach will allow us to e valuate the resource potential of the largely unexplored, formerly disputed border region while preserving a link to lithospheric-scale processes resulting in wider areas of uplift and subsidence, in particular the deep sag basins of the eastern Barents S ea, a number of structural highs in the Central Barents Sea, and the pervasive erosion related to Neogene uplift.