Geomechanical Assessment of Ground Surface Uplift due to CO2 Storage at In Salah, Algeria

This work presents an analysis of surface uplift above three injection wells at the In Salah (Algeria) and correlates the surface uplift to geomechanical processes in the reservoir. We integrate InSAR data, injection data and microseismic events to explain the displacement response of the reservoir and overburden to CO2 storage. The InSAR data covered time period of 2003 to 2012. Several cross sections at surface were selected around the injectors' wellheads for to analyze surface uplift. Surface displacement was then correlated to injection and microseismic data. The maximum cumulative vertical displacement from 2009 until end of the injection period in (6 March 2011) was about 15 to 20 mm. The absolute uplift was largest above well KB-502, but it was about the same magnitude above the other two wells. We can conclude that i) the maximum displacement was observed in the beginning of the injection period and for those points located right above the injection section, ii) surface heave shows a time delay of about 5 months relative to the injection period, and iii) surface uplift occurs during both matrix and fracture injection periods.