Impact of Intermittency on Salt Precipitation During CO2 injection

We study the effect of different parameters such as injection rate, permeability, and capillary pressure(grouped as capillary number) on salt precipitation and CO2 propagation within the reservoir duringintermittent injections. Recent development in the open-source OPM Flow simulator allows to include saltprecipitation in CO2 storage simulations. The logarithmic extension for the capillary pressure curve on thedry-out zone and the Killough model for hysteresis are adopted. To set up the reservoir grid, schedule inthe injection, and rock and fluid properties, we have developed an open-source framework in Python. Then,the setting of the simulations is achieved via a configuration file that allows not only for reproducibilityof the presented results, but to simulate additional scenarios. We show a comparison to published resultsusing TOUGH2, resulting in a good agreement between both simulators. We present a sensitivity studywhere the impact of different modelling choices (e.g., using a well model where the flow is uniform, or theflow adapts to the reservoir connectivity) is assessed. Simulations in heterogeneous layered systems usingthe facie properties from the recent SPE CSP11 problem definition is also presented. Finally, the effect ofalternating injection/shut-in periods (1 year per period) is assessed for the same amount of injected CO2in a time frame of eight years, resulting in 35 cases starting with CO2 injection. The results reveal thatduring more extended shut-in periods, salt precipitation is happening closer to the wellbore which confirmsthe effect of capillary pressure on imbibing more brine into the dried regions. Quantities such as solubilitytrapping and the integral of the well bottomhole pressure over time (used as an energy proxy) highly dependon the intermittency pattern.