Signatures of fluid-fluid displacement in porous media: wettability, patterns, and pressures

Abstract

We develop a novel `moving capacitor' dynamic network model to simulate immiscible fluid-fluid displacement in porous media. Traditional network models approximate the pore geometry as a network of fixed resistors, directly analogous to an electrical circuit. Our model additionally captures the motion of individual fluid-fluid interfaces through the pore geometry by completing this analogy, representing interfaces as a set of moving capacitors. By incorporating pore-scale invasion events, the model reproduces, for the first time, both the displacement pattern and the injection pressure signal under a wide range of capillary numbers and substrate wettabilities. We show that at high capillary numbers the invading patterns advance symmetrically through viscous fingers. In contrast, at low capillary numbers the flow is governed by the wettability-dependent fluid-fluid interactions with the pore structure. The signature of the transition between the two regimes manifests itself in the fluctuations of the injection pressure signal.

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Cited by in corpus (7)

• Capillary fluctuations and energy dynamics for flow in porous media
• Pore-scale direct numerical simulation of Haines jumps in a porous media model
• Characteristics of fluid-fluid displacement in model mixed-wet porous media: patterns, pressures, and scalings
• Axisymmetric displacement flows in fluid-driven fractures
• X-ray Tomographic Micro-Particle Velocimetry in Porous Media
• Simulating volume-controlled invasion of a non-wetting fluid in volumetric images using basic image processing tools
• Thermodynamics of fluctuations based on time-and-space averages