Comparative analysis of rock physics models and acoustic response change in basalt after CO₂ injection

Since the industrial revolution, CO2 concentration has increased exponentially which has caused a rise in global average temperature. Geological carbon sequestration provides a solution to mitigate the climate change risks. Basalt is a promising target to store CO2 as it forms stable carbonate minerals, yet its impact on elastic properties of reservoir is not well studied. This study utilizes different rock physics models to model elastic properties of basalt flows and found that DEM offers the best accuracy. Laboratory acoustic measurements on pre and post CO2 injected basalt samples show the decrease in velocity. This shows that basalt is in the dissolution phase due to the formation of carbonic acid, which alters its elastic properties, hence decrease in velocity.