CO2 storage

- reservoir characterisation, sealing capacity and monitoring

Subsurface storage of CO2 is a promising candidate to reduce greenhouse gas emission. Understanding of the geomechanical properties of both the reservoir and the sealing cap-rock is important for the overall evaluation of a potential CO2 storage site.

Identification and understanding of changes in material properties as a result of interaction with CO2 rich fluids, as well as monitoring and modelling methods for injected CO2 is important for successful storage of CO2.

Pore fluid pressure due to injection can create new fractures in the reservoir rock or cause failure in pre-existing faults that provides conduits for the escape of CO2-rich fluid and subsequently leakage.

NGI offers

High quality rock mechanical testing including special test with possibilities for flooding with supercritical or liquid CO2
Structural and geological characterization of test samples to study interaction between CO2 rich pore fluid and the rock
Experiments on reservoir rock (sandstone), cap rock (shale) and overburden (mudstone)
Coupled geomechanical (poroelastic) and fluid flow modelling with realistic fluid properties relevant for CO2 injection (solubility and temperature effects)
Low frequency electromagnetic seismic (CSEM) modelling for monitoring CO2 injection and storage
Laboratory measurements of the resistivity as a function of co2 saturation
Seismic modelling with focus on fractured reservoirs and the response on acoustic velocities due to CO2.

Laboratory experiments with CO2

Flow through cell for flooding of both intact and fractured material with CO2 or CO2 dissolved in pore fluids. The pressure and temperature conditions are allowing CO2 in a supercritical state during the test.

Special core flooding facility investigating the effect of CO2 on geomechanical properties of shale

Tests include measurements of:

Permeability
CO2 breakthrough pressure
Acoustic velocities in axial direction
Axial and radial deformation
Microstructural characterisation for evaluation of changes in pore structures

Modelling of CO2 injection

Numerical models consider the two-phase flow of pore water and the injected CO2 and a fully coupled two-way interaction between the fluid flow and the solid displacement using linear Biot poroelasticity theory. The model can be used to: