In situ triaxial testing to determine fracture permeability and aperture distribution for CO2 sequestration in Svalbard, Norway

On Svalbard, Arctic Norway, an unconventional silicidastic reservoir, relying on (micro)fractures for enhanced fluid flow in a low-permeable system, is investigated as a potential CO2 sequestration site. The fractures' properties at depth are, however, poorly understood. High resolution X-ray c...

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Bibliographic Details
Published in:Environmental Science & Technology
Main Authors: Van Stappen, Jeroen, Meftah, Redouane, Boone, Marijn, Bultreys, Tom, De Kock, Tim, Blykers, Benjamin, Senger, Kim, Olaussen, Snorre, Cnudde, Veerle
Format: Article in Journal/Newspaper
Language:English
Published: 2018
Subjects:
Earth and Environmental Sciences
RAY COMPUTED-TOMOGRAPHY
FLUID-FLOW
MICRO-CT
PORE-SCALE
RESERVOIR SANDSTONES
LAB
STORAGE
COAL
SEGMENTATION
VALIDITY
Arctic
Svalbard
Norway
Small Rock
De Geerdalen
Online Access:https://biblio.ugent.be/publication/8559230
http://hdl.handle.net/1854/LU-8559230
https://doi.org/10.1021/acs.est.8b00861
https://biblio.ugent.be/publication/8559230/file/8559231
Description
Summary:On Svalbard, Arctic Norway, an unconventional silicidastic reservoir, relying on (micro)fractures for enhanced fluid flow in a low-permeable system, is investigated as a potential CO2 sequestration site. The fractures' properties at depth are, however, poorly understood. High resolution X-ray computed tomography (micro-CT) imaging allows one to visualize such geomaterials at reservoir conditions. We investigated reservoir samples from the De Geerdalen Formation on Svalbard to understand the influence of fracture closure on the reservoir fluid flow behavior. Small rock plugs were brought to reservoir conditions, while permeability was measured through them during micro-CT imaging. Local fracture apertures were quantified down to a few micrometers wide. The permeability measurements were complemented with fracture permeability simulations based on the obtained micro-CT images. The relationship between fracture permeability and the imposed confining pressure was determined and linked to the fracture apertures. The investigated fractures closed due to the increased confining pressure, with apertures reducing to approximately 40% of their original size as the confining pressure increased from 1 to 10 MPa. This coincides with a permeability drop of more than 90%. Despite their closure, fluid flow is still controlled by the fractures at pressure conditions similar to those at the proposed storage depth of 800-1000 m.

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