Phase diagram of quasi-static immiscible displacement in disordered porous media
Abstract
Immiscible displacement in porous media is common in many practical applications. Under quasi-static conditions, the process is significantly affected by porous media's disorder and pore surface's wettability. Previous studies focused on wettability effects, but the impact of the interplay between disorder and contact angle is not well understood. Here, we combine microfluidic experiments and pore-scale simulations with theoretical analysis to study the impact of disorder on the quasi-static displacement from weak imbibition to strong drainage. We define the probability of overlap to link the menisci advancements to displacement patterns, and derive a theoretical model to describe the lower and upper bounds of the crossover zone between compact displacement and capillary fingering for porous media with arbitrary flow geometry at a given disorder. The phase diagram predicted by the theoretical model shows that the crossover zone, in term of contact angle range, expands as the disorder increases. The diagram further identifies four zones to elucidate that the disorder impact depends on wettablity. In zone I, increasing disorder destabilizes the patterns, and in zone II, a stabilizing effect plays a role, which is less significant than that in zone I. In the other two zones, invasion morphologies are compact and fingering, respectively, independent of both contact angle and disorder. We evaluate the proposed diagram using pore-scale simulations, experiments in this work and in the literature, confirming that the diagram can capture the disorder effect on displacement under different wetting conditions. Our work extends the classical phase diagrams and is also of practical significance for engineering applications.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.H13R2019H
- Keywords:
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- 1805 Computational hydrology;
- HYDROLOGY;
- 1832 Groundwater transport;
- HYDROLOGY;
- 1847 Modeling;
- HYDROLOGY