VSP Monitoring for CO2 Migration Tracking in Fractured Rock Massifs

The suitability of the geological formations for use as a CO2 storage site must be determined through detailed characterization and assessment of the potential storage complex and surrounding area. At Hontomin in Northern Spain, this is a deep saline aquifer in a carbonated and fractured rock mass. It is necessary to check continuously the carbon dioxide displacement around the injection well, to analyse the potential migration pathways and build the dynamic model in a fractured media. The VSP technique, improved with permanent devices located inside the wells, could be the solution for the objective described. Geophone and DAS VSPs are compared and comparisons are also made between the recorded data and images from the four source positions used in the DAS VSP campaign. The imaged DAS VSPs are promising.