Carbon geosequestration in limestone: Pore-scale dissolution and geomechanical weakening

摘要: Abstract Carbon dioxide geosequestration in deep saline aquifers or oil and gas reservoirs is a key technology to mitigate anthropogenic greenhouse emissions. Porous carbonate rock potential host for CO 2 storage; however, chemically reacts when exposed the acidic brine (which created by addition of , -saturated brine). These reactive transport processes are only poorly understood, particularly at micrometre scale, importantly how this affects geomechanical properties. We thus imaged heterogeneous oolitic limestone (Savonnieres limestone) core before after flooding with representative reservoir conditions (323 K temperature, 10 MPa pore pressure, 5 MPa effective stress) in-situ high resolutions (3.43 μm 1.25 μm voxel size) 3D an x-ray micro-computed tomograph; measured changes nano-scale mechanical properties induced acid exposure. Indeed matrix partially dissolved, absolute porosity permeability significantly increased. This dissolution was confined original flow channels inlet points. Importantly, weakened (- 47% indentation modulus) due