Spontaneous Imbibition as Indicator of Wettability Change During Polymer Flooding
J.L. Juarez-Morejon, H. Bertin, A. Omari, G. Hamon, C. Cottin, G. Bourdarot and D. Morel
Event name: IOR 2017 - 19th European Symposium on Improved Oil Recovery
Session: Polymer II
Publication date: 24 April 2017
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The presence of polymer molecules in an altered wettability core and its possible interactions with the solid phase is the subject of this study. Experiments were carried out in Bentheimer sandstone which wettability is altered by an ageing process. The wettability index after ageing (WI = 0.075) shows an intermediate wettability. After ageing we carried out spontaneous imbibition tests by putting in contact the core with brine or polymer solution (HPAM, C = 2500ppm) or in a sequence (first with brine and then with the polymer solution) For each experiment we measure the volume of oil recovered by spontaneous imbibition, this oil volume gives us an evaluation of the core wettability, the higher the recovered oil volume, the more water wet is the core. The experimental data show that final oil production by spontaneous imbibition is higher when the core was kept for a long time in contact with polymer solution rather than with brine. Moreover if the core is put in contact with polymer after having been immerged in brine, we notice a significant increment of produced oil. All these results confirm that the polymer has an interaction with the solid phase and makes the core more water wet.