Flow-dependency aspects in SCAL of steady-state two-phase flow in model pore networks.

In the current phase of an ongoing study, we systematically investigate the effects of pore
network geometry and wettability on two-phase flow in porous media. The aim is to address the problem
of end-effects in SCAL measurements. Systematic, steady-state, co-injection experiments are conducted in
planar, transparent microfluidic networks: a periodic and a non-periodic network made of PDMS, and a
periodic network made of glass. This setup enables isolation and comparison of the effects of network
geometry and wettability for a broad domain of flow conditions spanning 3 orders of magnitude of the
capillary number and the flowrate ratio. Taking ex-core measurements of pressure drops, we extract the
dependence of the relative permeabilities and the intrinsic dynamic capillary pressure on the flowrates, for
each examined system. We have developed a specialized imaging algorithm to monitor the spatiotemporal
evolution of statistical properties of the interstitial flow in steady-state and transients (flowrate bump
increments). We also evaluate the establishment of fully-developed interstitial flow and we correlate it to
the interstitial flow structure and the magnitude of end-effects. The work provides mechanistic insights
that have a potential for improving SCAL protocols. The ultimate aim is to generate flow-dependent
relative permeability maps that are true to the underlying physics, thereby enhancing the specificity,
reliability, and predictive accuracy of reservoir simulation models.