GEO ExPro

Disproving The Theory

A significant discovery of light oil in sandstones with excellent porosity has been made on the Tampen Spur in the North Sea. Prior to this find, the area was thought to be both gas-prone and to have poor reservoir parameters.
This article appeared in Vol. 5, No. 5 - 2008

Advertisement


X-section of the Jordbær structural trap with reservoir in the Lower Jurassic Cook Formation. The downfaulted prospect Jurassic East may at best add another 600 MMboe. © Revus Energy The Tampen Spur is a multibillion barrels geological province in the northern North Sea. Its prolific extension to the northeast is now indicated by the Jordbær discovery. © Revus Energy The Tampen Spur in the Northern North Sea became famous because of several giant oil fields discovered in the 1970's. Most of you will be familiar with names such as Statfjord, Gullfaks, Snorre and Brent (compare map), of which Statfjord on one particular day produced more than 800,000 barrels. The Tampen Spur is thus known as a prolific hydrocarbon province. Recent news demonstrates that this province still has a lot to offer.  

The Tampen Spur is a structural high in the Northern North Sea. The play model includes Upper Jurassic source rocks, predominantly Middle and Lower Jurassic reservoir rocks and Upper Jurassic and Lower Cretaceous cap rocks. Following rifting that ceased in the Late Jurassic-Early Cretaceous, the Cenozoic developed as a thermal sag basin on top of a series of Mesozoic rift structures that now provide excellent traps.

The northern North Sea has developed into a mature province, and the combination of significant in-place volumes and highly productive reservoirs has rarely been achieved in discoveries made in the last 15 years. This has now changed. A recent well operated by British Gas proves the continued excellent exploration potential of the Tampen Spur.  

Following successful completion of a side track on the Jordbær ("strawberry") Central discovery announced in August, an extension of that oil discovery has now been confirmed. Preliminary estimates made by Revus Energy indicate recoverable reserves of between 57 and 100 MMboe. This range does not, however, include potential volumes held in an undrilled segment of Jordbær Central.  

"Both wells have proven light oil with very good reservoir quality. We believe there is a high likelihood of additional volumes in the undrilled segment and in several adjacent prospects", says Harald Vabø, CEO of Revus Energy.  

Revus Energy believes the additional volume potential in the undrilled segment is 30-40 MMboe. The company further sees significant potential in adjacent exploration prospects including gross unrisked potential of 300 MMboe in the Blåbær ("Blueberry") prospects (low to medium risk), up to 600 MMboe in the Jordbær East prospect (medium risk) and up to 500 MMboe in the Plomme ("Plum") prospects (medium risk).  

"Aside from the large volume potential, the very favourable reservoir conditions encountered indicate that high production rates per well can be expected upon a potential development of Jordbær," says Harald Vabø.  

This is the fun of exploration: Be prepared for surprise, and make sure you have a mindset that lets you change the exploration model when deemed necessary.

Advertisement

Related Articles