London (Platts)--24Sep2007

A report by Norwegian gas pipeline operator Gassco and the Norwegian
Petroleum Directorate has identified fields near Sleiper and Troll as the best
for storing carbon dioxide.

     "Carbon dioxide can be stored in the Norwegian continental shelf. In the
North Sea, the Utsira formation near the Sleipner field and the Johansen
formation in the area around the giant Troll field are the best suited," finds
the report, which was prepared for the energy minister. The assignment was to
recommend good solutions for transport and disposal of CO2. 

     Based on their knowledge of the Norwegian shelf, NPD geologists selected
alternative storage sites for more detailed mapping.  The geological data and
knowledge necessary to find a suitable storage site relate to finding large
volumes of sandstone or some other reservoir rock that is well-sealed so that
gas and liquids cannot leak out. 

     The largest volumes of sand and sandstone that may be suitable for
disposal of CO2 on the Norwegian shelf are in the Utsira formation and the
underlying Skade formation in the area around the Sleipner field.  The
Johansen formation under Troll has also been evaluated. 

     The Utsira formation is used for storing CO2 from Sleipner and as a
source of water for water injection on Oseberg.  The advantage of the Utsira
and Skade formations is that they have abundant amounts of sandstone. Statoil
has proven that Utsira can function as a storage site. 

     It is uncertain whether the Utsira formation is suitable for future
large-scale storage of Europe's CO2 emissions, but the work indicates that
there is more than adequate storage capacity in the area surrounding
Sleipner--both to cover Sleipner's needs and to store emissions from Karsto,
Mongstad and elsewhere. 

     The advantage of the Johansen formation is that it forms a deep, closed
structure where injected CO2 cannot leak to the surface. The most important
uncertainty the geologists need to clarify is whether there may be a risk that
CO2 could leak to Troll. The NPD's mapping indicates that this is very
unlikely.