CO2 Sequestration [Induced Seismicity; Geo-mechanics]

1. Whether anthropogenic changes in the state of stress of the aquifer unit – would artificially, induce seismicity – upon CO2 injection?

If yes, then, what would be the intensity (mild/moderate) of the induced earthquakes – resulting from the enhancement in aquifer pore pressure?

Can it damage the infrastructure @ storage site (in the long run); or, Can damage any nearby facilities?

Can it damage the cap-rock/seal (paving way for CO2 leakage)?

2. Feasible to have geo-mechanical data @ CO2 storage sites – during the early phases of CO2 site evaluation – that could forecast ‘fault slip’?

Unlike depleted oil/gas reservoirs, where, historical information from water-injection and oil/gas-production – can be used to analyze the factors influencing induced seismicity (which includes the estimation of likely-timing; location; intensity and numbers of induced earth-quakes), how about the same in deep saline aquifers?

So, how do we deduce the risk arising from induced seismicity @ CO2 storage site - associated with a deep saline aquifer?

Would require more numbers and locations of seismometers relative to the induced earthquakes?

Feasible to monitor and have a control over - the clustering of a large number of small earthquakes @ injection depths of the aquifer, which continues for, as long as, the pore-pressures in the hypo-central region gets elevated?

Possible to end up with a relatively larger earth-quake, produced by processes other than CO2 injection (say, from the estimated state of stress in the crust exceeding the aquifer rock strength)?

Even with depleted oil/gas reservoirs, if the volume of fluid mobilized @ injection sites remain to be lesser than 1 million m^3 (which is much lesser than the required volume of CO2 mobilization of around 100/1000 million m^3 for commercial CO2 storage sites), then, how to go about - deducing the details of induced earth-quakes - even in depleted oil/gas reservoirs?

Are there any other critical parameter(s) of interest that depend on the estimation of frequencies and magnitudes of induced earthquakes (productivity of induced seismicity) – apart from its dependence on aquifer-pressure, aquifer porosity/permeability and the total volume of injected CO2?

How exactly to handle the scenario, where, there is an earthquake, soon after, the onset of CO2 injection operations; and, which remain, very closer to the CO2 injection well itself?

Is there a possibility of a CO2-leakage related earthquake – with a relatively greater focal depth - which has the potential to induce crustal-scale deformation and seismicity (in the long run)?

What happens, when seismicity records, the migration of the pressure-front created by CO2-injection or CO2-leakage, which may not necessarily coincide with the margins of the plume?

Suresh Kumar Govindarajan

https://home.iitm.ac.in/gskumar/

https://iitm.irins.org/profile/61643