Fast fluorescence-based microfluidic method for measuring minimum miscibility pressure of CO2 in crude oils

Carbon capture, storage, and utilization has emerged as an essential technology for near-term CO2 emission control. The largest CO2 projects globally combine storage and oil recovery. The efficiency of this process relies critically on the miscibility of CO2 in crude oils at reservoir conditions. We present a microfluidic approach to quantify the minimum miscibility pressure (MMP) that leverages the inherent fluorescence of crude oils, is faster than conventional technologies, and provides quantitative, operator-independent measurements. To validate the approach, synthetic oil mixtures of known composition (pentane, hexadecane) are tested and MMP values are compared to reported values. Results differ by less than 0.5 MPa on average, in contrast to comparison between conventional methods with variations on the order of 1-2 MPa. In terms of speed, a pressure scan for a single MMP measurement required less than 30 min (with potential to be sub-10 min), in stark contrast to days or weeks with existing approaches. The method is applied to determine the MMP for Pennsylvania, West Texas, and Saudi crudes. Importantly, our fluorescence-based approach enables rapid, automated, operator-independent measurement of MMP as needed to inform the world's largest CO2 projects.