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2. Summary from the Phase 1 final report 2007 - 2009

The Longyearbyen CO2 lab Phase 1 project was finalized in December 2009, after performing extensive drilling with 
coring and finally injection testing of the targeted upper Triassic Kapp Toscana Group reservoir section below Long-
yearbyen. The reservoir section contains sandstone of very low to low and variable permeability and low to moderate 
porosity. On the contrary, the rocks have fairly good injectivity, suggesting that fractures promote flow. It was there-
fore conclude that there is a dual-permeability reservoir in the subsurface near Longyearbyen. The following Phase 2 
project (this report) of 2010 to December 2014, had years that focussed on qualifying injectivity, better constraining 
the reservoir volume, and further testing the caprock properties. 

Four wells were drilled in the Phase 1 project of 2007-2009, Dh1, Dh2 (1A), Dh3 and Dh4. They are 560, 860, 403 and 
970 m deep, respectively. Dh’s 1 and 3 were abandoned in the cap rock section due to technical problems, whereas Dh2 
reached the upper reservoir section before the operation experienced technical failure and subsequent abandon-
ment. Due to these technical challenges, drilling experts from partner companies came on-board to assist. Accord-
ingly, before the Dh4 drilling commenced there were significant considerations around the equipment and the mud 
program. With these updates to the drilling program, Dh4 reached the targeted depth. 

From the seismics, comparison between reflectors and drill hole information shows that several units are clearly vis-
ible is the seismic system. They more or less correlates to the base of the Helvetiafjellet Formation, a reflector near 
the base of the Cretaceous section, another near the top of the Wilhelmøya Subgroup, and one reflector within the 
De Geerdalen Formation reservoir. In addition, there are two strong reflectors related to intrusions. 

Since the seismic has a regional, 2D character, derived surface maps have significant uncertainty on a detailed level. 
However, in the up-slope direction to the NE, combined field data and seismics suggest there are no physical closures 
(anticlines). Instead, the reservoir climbs gently (1-3 degrees) in this direction towards outcrops in the NE, with reser-
voir sandstones reaching the surface 15-20 km from Longyearbyen. 

The reservoir succession of the Kapp Toscana Group as seen in Dh2 and Dh4 suggests that the entire unit is tidal to 
shallow marine, spanning from lagoon to tidal inlet delta to barrier spit and open marine deposits. The net sandstone 
of the succession is around 25-30%, whereas net permeable sandstone is lower, probably closer to 10-15%. Signifi-
cant uncertainty around injectivity of the Wilhelmøya Subgroup existed at this stage, since this unit was not tested 
by water injection. However, the core data suggested this unit as the best matrix reservoir, offering longer sections 
of sandstone with fairly good Miniperm characteristics.

Porosity measurements of the sandstones gave low to moderate values in the sandstones. In total, 85 measurements 
from core of Dh2 and Dh4 reveal porosity values between 5 and 18%, with an average for the reservoir sandstones 
of nearly 15 %. The permeability is however low, with a maximum of 2 mD. Accordingly, good injectivity in drill holes 
points to flow on fractures.

Above: Logg figure as it was at the end of Phase 1 

Figure by: Kei Ogata

Project Summary  

2007 - 2014