Avoiding loss of CO₂ injectivity

-    Goal of the Project: The overall objective is to investigate how, where and when injectivity in a CO₂ well is lost due to precipitation of salt or formation of hydrates -and which operational parameters minimize the risk of reduced injectivity. The project aims to provide an evaluation of whether CO₂ hydrates may serve as a self seal above the storage zone and increase the security of the storage.

-    Technical content: Experiments will be performed where rock samples are flooded with CO₂ at relevant pressure and temperature, to induce salt precipitation and hydrate formation. The samples will then be investigated using characterization techniques like X-ray tomography and magnetic resonance imaging to determine where clogging has occurred.
A numerical model will be developed for flow and thermodynamics of CO₂-water-salt/hydrate in the near-well zone.

-    Technical advantages: Research-based recommendations will be provided on operational parameters that minimize the risks for reduced injectivity due to salt and hydrates.

-    R&D challenges:

•    Design experimental campaigns within realistic downhole conditions that identify nucleation and growth mechanisms of salt/hydrate formation, as well as effects on permeability of the rocks.
•    Design and implement modelling plan that demonstrates important thermodynamic aspects of flow and salt/hydrate precipitation in rocks, guided by experimental results.
•    Provide operational parameters that minimize the risks for reduced injectivity due to salt and hydrates

-    Results to date: The project is in the start-up phase. Currently, experimental campaigns are designed and the first X-ray tomographic microscope pictures of sandstone samples are available, obtained at the European synchrotron facility ESRF. The implementation plan for modelling work is almost complete, and many qualified applications for a postdoc position are being evaluated.