Jurassic, Realgrunnen Sub-Group Prospectivity from the Bjarmeland Platform - Results of Wells 7226/2-1 and 7224/6-1

Richard Martin, Bente Fotland, Inger Laursen, Alf Eivind Ryseth, and Kyrre Simonsen
Exploration Northern Areas, StatoilHydro, Harstad, Norway.

Seismic data collected in the late 1990s and extensive reprocessing of vintage 2D data in 2002-2003, indicated likely DHIs in Jurassic sandstones present over large structures in the Central and South Western parts of the Bjarmeland Platform. These DHIs appeared to represent class IV AVO anomalies, fitted to structure, and appeared similar to anomalies present at equivalent intervals in the Russian Sector of the Barents Sea.

The delivery of 3D seismic over two of these structures in 2007 confirmed the presence of DHIs, but they now appeared as class III anomalies. In 2008 two exploration wells (7226/2-1 and 7224/6-1) were subsequently drilled on the 'Ververis' and 'Arenaria' structures.

The results showed good quality sandstones from the Realgrunnen Sub-Group, a possible palaeo-hydrocarbon column within the structures, and thus, a once working hydrocarbon system. The results point to trap integrity and / or seal breach as a possible cause of failure. If so this is likely the result of their present shallow burial depth and history of uplift and erosion. Trap breach could have been caused by mechanical or capillary leakage through the top seal as a result of over pressuring during uplift, fault reactivation resulting in juxtaposition leakage or leakage through fault gouge, or, simply migration through an already breached trap.

Data collected from the Jurassic intervals in these wells will be illustrated and a post-mortem of the wells discussed.

AAPG Search and Discover Article #90096©2009 AAPG 3-P Arctic Conference and Exhibition, Moscow, Russia