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Coring the permafrost 

Goals: Establish shallow subsurface fluid migration characteristics in the well park area. Core the permafrost overburden dur-
ing drilling. Map and characterize pockmarks and understand the links between submarine pockmarks and subaerial leakage. 
Map gas fluxes in the well area.

Leakage and permafrost

     

     

- Christiansen et al.

Permafrost Core Sample - 2009

Photo b

y; Christian, H

.

Figure left by G.L. Gilbert  - 2014

Simplified sedimentary log with facies and faci-
es association distributions. The intensity of bi-
ogenic activity decreases upwards in relation to 
coarsening and shallowing of the deposits. The 
grain size distribution is included to provide con-
text for the location of facies and facies associ-
ations . Note that crossed out boxes indicate the 
location of unretrieved intervals.

Permeability of tight sandstones 

      - 

Magnabusco et al. 2014

Permeability measurements of low-permeability sandstone units within the strata cored in seven drill holes near to 
Longyearbyen, were analyzed to assess the presence of aquifers and their potentials as reservoirs for the storage 
of carbon dioxide. These targeted sandstones are located in the Late Triassic-Early Jurassic De Geerdalen and Knor-
ringfjellet formations, with some permeability found in the Cretaceous Rurikfjellet and Helvetiafjellet formations 
situated within otherwise impermeable cap-rocks.  Permeability and porosity data were acquired from drill plugs, 
analyzed in the laboratory by flooding of H2O, He and Hg, and compared with direct measurements manually collect-
ed from cores with a Miniperm instrument. 

The sandstones are tight (< 2mD) due to extensive diagenesis. The two methods produced permeability results of 
up to one order difference in magnitude; however, when correlated, these methods offer a robust linear relationship 
that can be applied as a correction function. Detailed mapping of drill core with Miniperm, corrected by the proposed 
function, allow analysis of tight reservoir permeability on a very detailed scale, which identify otherwise unrecog-
nized permeable zones. In the analyzed reservoir sandstone succession, 2 out of 30 meters has recognizable perme-
ability above the threshold of the Miniperm. In the upper part of the reservoir (Knorringfjellet Formation), where data 
are from three closely spaced wells, the permeability field can be divided into through-going and isolated zones, of 
which ca. 10% is through-going. In the explored Late Triassic to Cretaceous succession of Central Svalbard, the Knor-
ringfjellet Formation sandstones and conglomerates have the best matrix properties for storage of carbon dioxide.

Plot of permeability versus depth showing core plugs and Miniperm measurements, with Miniperm data adjusted 
according to the correction function presented in Magnabusco et al. (2014).

Since the project started in 2007 the permafrost has been considered as an additional security; acting as a top seal to the 
reservoir. With this consideration the lab funded research to this effect. Under the guidance of Hanne Christian and her team 
from UNIS, University of Oslo, University of Copenhagen and University of Århus in 2012 DH8 was drilled and cored.

  A 62 m 

core was retrieived this almost continuous core extends through the overburden from ca. 1 m below the ground surface to the 
bedrock-sediment interface at ca. 60 m depth.

Few studies have attempted to retrieve cores from permafrost environments to such depths. With some exceptions, previous 
investigations have been limited to a depth of ca. 10 m, and so focused exclusively on conditions within the near surface. 

(see report; Project number Gassnova/Climit: 218953) “Longyearbyen CO2 Lab2012-2013 Status report–November 1st 2013”)

This is the first study to investigate the Holocene permafrost development of the sedimentary deposits in lower 
Adventdalen. Given the geomorphological similarities between Adventdalen and other large valleys in western and 
central Spitsbergen, the sedimentary and geocryological model presented in this investigation may be applicable to 
other areas. The results of this investigation have implications for infrastructure development in the Adventdalen 
area as well as future permafrost and sedimentological studies in Arctic environments.

Observations made during this investigation suggest that the all retrieved deposits are ice-bonded under the ther-
mal regime prevailing at the study site. Indeed, it is unlikely that retrieval of these deposits would have been possible 
without the presence of pore ice. Frozen deposits of this nature are likely characterized by low permeability; a fa-
vourable trait for investigations interested in storing carbon dioxide below the ground surface.