Assessing induced seismicity risk at CO2 storage projects: Recent progress and remaining challenges

It is well established that fluid injection has the potential to induce earthquakes-from microseismicity to magnitude 5+ events-by altering state-of-stress conditions in the subsurface. This paper reviews recent lessons learned regarding induced seismicity at carbon storage sites. While similar to other subsurface injection practices, CO2 injection has distinctive features that should be included in a discussion of its seismic hazard. Induced events have been observed at CO2 injection projects, though to date it has not been a major operational issue. Nevertheless, the hazard exists and experience with this issue will likely grow as new storage operations come online. This review paper focuses on specific technical difficulties that can limit the effectiveness of current risk assessment and risk management approaches, and highlights recent research aimed at overcoming them. These challenges form the heart of the induced seismicity problem, and novel solutions to them will advance our ability to responsibly deploy large-scale CO2 storage.