RWE Dea Norge AS, operator of production licence 420, has completed drilling of appraisal wells 35/9-11 S and 35/9-11 A on the 35/9-6 S oil, gas and condensate discovery.
The discovery was proven in Jurassic reservoir rocks in the winter of 2010. Appraisal wells 35/9-11 S and 35/9-11 A were drilled 1.7 kilometres southwest of the 35/9-6 S discovery well. Before wells 35/9-11 S and A were drilled, the operator’s resource estimate for the discovery was between 2 and 10 million Sm3 recoverable oil equivalents. Well 35/9-11 A was drilled 30 metres from 35/9-11 S for optimal core samples.
The objective of the wells was delineating the 35/9-6 S discovery to the southwest by proving additional resources and reducing the uncertainty regarding reservoir thicknesses and properties.
Wells 35/9-11 S and 35/9-11 A encountered oil in the Heather formation, Brent Group, Drake formation and top part of the Cook formation and Statfjord Group in Jurassic reservoir rocks. The reservoirs have different pressure regimes. Formation water was encountered in the lower part of the Cook formation, but no oil/water contact was encountered in the other formations.
The reservoir quality in the Heather, Tarbert, Etive, Cook formations and Statfjord Group is poor. Extensive data acquisition and sampling have been carried out. Pressure data indicates that there is no communication with the northern part of the 35/9-6 S discovery. The resources in the discovery will now be evaluated based on the results from the new wells.
These are the second and third exploration wells in production licence 420. The licence was awarded in February 2007 (APA 2006).
Appraisal wells 35/9-11 S and 35/9-11 A were drilled to respective vertical depths of 3733 and 3795 metres below the sea surface with associated measured depths of 3800 and 3860 metres below the sea surface. 35/9-11 S was terminated in the Dunlin Group and 35/9-11 A in the Statfjord Group, both in Lower Jurassic. Water depth is 368 metres. The wells were temporarily plugged and abandoned.
The wells were drilled by the Leiv Eiriksson drilling facility, which will now proceed to production licence 554 in the northern North Sea to drill appraisal well 34/6-3 S, where Total E&P Norge AS is the operator.