In Salah CO2 storage JIP: Carbon dioxide plume extension around KB-502 well–New insights into reservoir behaviour at the In Salah storage site

AbstractSurface uplift has been detected over all three of the In Salah CO2 injection wells with corresponding subsidence also observed over the gas production area. In particular, it has been noted that the surface uplift over KB-502 displays two distinctive lobes aligned along the direction of the maximum principal stress in the region, originating from the heel and the toe of the horizontal wellbore respectively. As part of the work programme within the EU funded CO2ReMoVe project, Imperial College has carried out short-term reservoir simulations of CO2 injection into the aquifer portion of the C10.2 sandstone formation, initially focusing on history match of injection well pressure at KB-502 and CO2 breakthrough at the nearby KB-5 observation well (now fully decommissioned) along the heel-side lobe. In view of the satellite monitoring data of the surface deformation at the Krechba gas field and published findings of the inversion modelling work, the reservoir model is further improved to account for the pressure distribution inferred from the surface uplift data, as well as the reservoir-based field data. Specifically, the permeability pattern inverted from the surface uplift data has been used to further constrain the reservoir model to improve prediction of the CO2 plume migration around KB-502, so that it is consistent with the surface monitoring data, as well as reservoir-based observations (injection pressures and CO2 breakthrough at KB-5)