Velocity-Dependent Foam Rheology in Porous Media for Enhanced Oil Recovery

We present an experimental investigation on the effect of velocity on foam rheology in porous media. Our study compared steady state foam strengths with respect to different interstitial velocities. It is observed that foam is shear-thinning at low velocity as predicted by the bubble-in capillary-tube model. But experimentally, we have observed that foam shear-thickens with increased velocity within porous media. Hypothesis is discussed in detail to search for the underlying mechanism. We propose that it is in-situ foam generation that explains the shear-thickening effect. More bubbles are generated at increased velocities (or higher pressure gradients), which causes stronger flow resistance. More interestingly, we find out that velocity-dependent foam strengths follow the same trend in low quality regime and it is different from the trend in high quality regime.