Probing the Riches in the Barents Sea

In late April it became known that Norway and Russia had agreed upon a common marine border in the Barents Sea. An area equivalent in size to the North Sea fairway was made available overnight. Fugro Multi Client Services has an extensive data base and good geological knowledge covering both sectors of the Barents Sea and Idar Horstad, General Manager, volunteered to share his thoughts about the prospectivity of this huge area.

Halfdan Carsten

Idar Horstad holds a MSc. and PhD. in Sedimentary Geology from the University of Oslo. His work at the University was focused on the understanding of the migration and emplacement of hydrocarbons on the Norwegian Shelf. He spent 10 years in the Exploration Group in Saga Petroleum before he joined Fugro in 2000. For the past 10 years he has been the Managing Director for Fugro Multi Client Services with a global responsibility for multi client seismic acquisition in Fugro. Photo: Halfdan Carstens

First of all, Idar, can you give us an idea about the size of this previously disputed area?

The previously disputed area is approximately 175,000 km², or roughly the size of 500 Norwegian Barents Sea blocks. This will be split roughly 50:50 so we should have another 250 blocks to evaluate and explore, meaning that this area will play a key role in future licensing rounds in Norway.

Size matters, but more importantly, does it have a petroleum system favourable for large accumulations?

The Barents Sea is an enormous area, covering more than 1,400,000 km²and the geology varies significantly across the region. Despite the limited exploration success to date on the Norwegian side, most of the area can still be regarded as a frontier basin. Source rocks and reservoirs are present at many levels, and exploring structures that potentially could be sourced from the same source rock kitchen as the Shtokman field will be exciting.

Source rock is a prerequisite, of course - do we have several possibilities?

Absolutely. Oil and gas prone source rocks are present from the Devonian and into the Tertiary in the Barents Sea. However, the scarce sampling and the complex burial and uplift history complicates the petroleum system and I think the key to success in the Barents Sea is a detailed understanding of the regional geology and how this has controlled the generation and migration of petroleum through time. The present structural setting represents only a snap shot that might be very different to the setting at the time of migration from the various source kitchens.

Then we also need reservoir rocks. Are we talking about clastics or carbonates, and which formations seem to be most promising?

To quote Winnie the Pooh when he was asked whether he would like condensed milk or honey on his bread - “Both”. There are many different reservoir levels but the thick Triassic section will make exploration in the Palaeozoic an expensive and high risk adventure in most of this area.

Published maps indicate that there are many huge structures, some of which could play host to supergiant fields. Is this true?

I think all geologists who have visited Russia have seen maps with large yellow and red dots. However, the amount of information is limited and we cannot assess the full potential until we have more modern data and a few key structures have been drilled to get a better understanding of the petroleum system in the border area on both sides. If the potential isn’t huge I would say it is very high - and getting access to new frontier regions is always good for the industry.

It is also said that the Russians have proved a giant gas field next to the median line. That must be good news for the whole area?

Previously we called this “oil on paper”. You haven’t proved a discovery until you have drilled and tested it, and you don’t make money until you develop, produce and sell it. Observations from seismic or other technologies, such as CSEM, can be applied to reduce the risk but these have less value if they aren’t calibrated by wells in the region.

Which, if any, would be the most negative geological factor for the prospectivity of the area?

Based on Fugros’ evaluation of the modern data I think the uplift and restructuring of the area offers a great challenge in addition, to the volcanic intrusions we see on the Russian side. The data are accessible and you can judge for yourselves.

Finally, Idar, I reckon you like the business opportunities this new situation presents. Are you ready?

Fugro is the only western contractor that has acquired and can offer modern long offset seismic data on both sides of the former disputed area. Old NPD and Russian 2D data were acquired with very short streamers and are inferior to these new data. At one stage Statoil was our only client, but we have had several people working in the Barents Sea since 2001, Today more than 30 companies have licensed the whole or parts of our new NBR long offset survey in the Barents Sea. This area represents a natural extension and as soon as the area opens for exploration Fugro will participate with our vast resources to collect geological and geophysical data.

Article from GEO ExPro Magazine NO3 - 2010