Residual CO2 trapping in oil-wet sandstone


  1. Residual CO2 trapping in oil-wet sandstone>
    . Residual trapping of CO2 in an oil‐filled, oil‐wet sandstone core: results of three‐phase pore scale imaging. Geophysical Research Letters. .

    Abstract — CO2 geo‐sequestration in oil reservoirs is an economically attractive solution as it can be combined with enhanced oil recovery (CO2‐EOR). However, the effectiveness of the associated three‐phase displacement processes has not been tested at the micrometer pore‐scale, which determines the overall reservoir‐scale fluid dynamics and thus CO2‐EOR project success. We thus imaged such displacement processes in‐situ in 3D with x‐ray micro‐computed tomography at high resolution at reservoir conditions, and found that oil extraction was enhanced substantially, while a significant residual CO2 saturation (13.5 %) could be achieved in oil‐wet rock. Statistics of the residual CO2 and oil clusters are also provided, they are similar to what is found in analogue two‐phase systems although some details are different, and displacement processes are significantly more complex.