Hydrocarbon leakage in a glacially influenced marine environment, Southwestern Barents Sea

The Barents Sea covers the north western corner of the Eurasian continental shelf with an area of approximately 1.2 x 10⁶ km² (figure 1); and overlies an intracratonic basin bounded by young passive continental margins to the west and north, that developed in response to the Cenozoic opening of the Norwegian-Greenland Sea and the Eurasia Basin, respectively (Faleide et al., 1993; Vorren et al., 1991). The south-western Barents Sea contains some of the deepest sedimentary basins world-wide. These basins formed in response to several phases of regional tectonism within the North Atlantic-Arctic region, culminating with continental separation of Eurasia and Greenland and accretion of oceanic crust in the Early Tertiary (Faleide et al., 1993).
During the last decade the Barents Sea has attracted considerable interest as a potential hydrocarbon province. The Norwegian Barents Sea with multiple source rock intervals should represent a prime example of an overfilled petroleum system. However, several episodes of uplift and erosion from the Paleocene until the Plio-Pleistocene have caused the depletion of hydrocarbon accumulations in the region. These uplift events were not only potentially catastrophic but have also caused the redistribution of the remaining oil and gas over laterally large distances in the Barents Sea region (Ohm et al., 2008).

Goals
This project aims to assess and quantify the amount of hydrocarbons that has been generated by the main source rocks present in the Southwestern Barents Sea and also to determine the amount of petroleum released to the surface as a response of tectonic events (uplift and erosion) and glaciations. The work will be performed using 3D-basin modeling (PetroMod V11) (figure 1). A first phase focuses on modeling four separate areas within the Barents Sea (Hammerfest, Bjørnøya and Nordkapp basins, and the drainage areas focusing on the Loppa High; figure 2). These selected areas are of interest because hydrocarbons are present and a possible leakage has been established or inferred, e.g. via the presence of pockmarks. In parallel we are investigating possible leakage sites using biomarker analysis, headspace GC and gas isotopic analysis on samples of recent sediments collected in the Barents Sea mainly in areas of pockmarks with the aim of characterizing the hydrocarbon types leaking and also determine the amounts of thermogenic and biogenic gas.
 

Figure 1: 3D-basin model of Hammerfest Basin with well locations

 

Figure 2 Map of Barents Sea with modelled study area and main strucrual element and sub-basins

Contact
E. Rodrigues 
Di Primio 
Z. Anka 
B. Horsfield

Partners
Lundin Petroleum Company