1 research outputs found
In Situ Triaxial Testing To Determine Fracture Permeability and Aperture Distribution for CO<sub>2</sub> Sequestration in Svalbard, Norway
On
Svalbard, Arctic Norway, an unconventional siliciclastic reservoir,
relying on (micro)Âfractures for enhanced fluid flow in a low-permeable
system, is investigated as a potential CO<sub>2</sub> 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