ARGUS

Summary

In the subsurface, fractures can act as fast conduits for fluid transport, where the geometry of the void space (most notably wall roughness and aperture) determines the transport properties. However, flow-through of a reactive fluid may affect this, coupling flow rate, transport of dissolved species, and stress in the solid. The project ARGUS will develop time-resolved X-ray and neutron imaging applications to unravel geological processes related to flow in rocks. Understanding the interactions between fluid flow and rock deformation has numerous fundamental applications in geosciences: groundwater movement, displacement of contaminants, geothermal energy, hydrocarbon exploration and subsurface storage of waste (such as processed water, CO2, or nuclear waste), and enhanced oil and gas recovery. Moreover, the transport of fluid in fault zones is also related to earthquakes, and how transport controls the occurrence of local chemical reactions and metamorphism at depth.

a) X-ray tomography uses the interaction between X-rays and the electron shells to image solid material. We will use the HADES rig to image fracture and flow in rocks at realistic in-situ pressure-temperature (p-T) conditions. b) Neutron tomography uses the interaction between neutrons and the atom nuclei to image fluids. We will use flow-through set-ups at ILL/UGA (Grenoble) and PSI (Villigen) to image fluid circulation in rocks, and gain competence in neutron imaging.

We will perform advanced time-lapse X-ray 3D tomography to image the fracturing of solid rock under pressure/temperature conditions representative for hydrocarbon reservoirs. Using our knowledge from X-ray imaging, we will adapt and develop 2D and 3D neutron imaging for flow in fractures. Furthermore, tomography data image processing to date is dependent on the operator, where user bias decreases reproducibility and may introduce errors. Therefore, we propose to apply innovative sementation routines, based on machine learing algorithms, to quantitatively describe the 3D morphology of the growing crack network and the flow, and to minimize errors.

Developing in-situ experiments and data processing routines will help us to build up towards usage of the new neutron imaging capacities currently being installed in Scandinavia. We aim to collect a database of reference samples and images of fractures and flow patterns in rocks that can be used for comparison between various X-rays and neutron sources.

Participants

University of Oslo

Lund University, Sweden

Paul Scherrier Institut, Switzerland

University of Edinburgh, UK

University Grenoble Alpes, France

Funding

Norwegian Research Council (Agreement 272217)
Long-term Proposal ES295, European Synchrotron Radiation Facility
Data storage is provided by UNINETT Sigma2 - the national infrastructure for high performance computing and data storage in Norway