MRI as a tool for the study of waterflooding processes in heterogeneous cores

NMR imaging has shown itself to be an important tool for improving analysis of flow behaviour during waterflooding in heterogeneous cores. Waterflooding is a widely employed technique in enhancing oil and gas recovery. However the success of such a process could be considerably reduced by instability of the displacing front with negative effects on production efficiency. MRI can be easily applied in evaluating the flow advancement because of its ability to distinguish different phases during dynamic experiments. In our study we have evaluated the shape of the displacing front during water injection in highly heterogeneous reservoir carbonates. The effect of petrographical heterogeneities which strongly characterize the rocks, revealed a marked influence on flow behaviour. Viscosity increase by polymer addition, in spite of a more favourable mobility ratio, resulted in a poorer performance because of higher channelling effects. The results of selected simulation experiments are discussed.