Wettability effect on wave propagation in saturated porous medium

Area of Science:

• Porous media physics
• Fluid mechanics
• Acoustics

Background:

• Fluid slip at boundaries is common in micro-fluid mechanics.
• In porous media, slip increases with hydrophobicity (non-wetting degree).
• Wettability significantly influences fluid slippage, quantified by slip length.

Purpose of the Study:

• To incorporate fluid slippage, using slip length as a wettability proxy, into Biot theory for elastic waves.
• To accurately predict acoustical properties of fluid-saturated porous media under varying wettability conditions.

Main Methods:

• Introduced slip length into calculations for viscous correction factor, dynamic permeability, and dynamic tortuosity within Biot theory.
• Analyzed the impact of wettability-driven slip on elastic wave propagation (phase velocity and attenuation).

Main Results:

• Elastic wave properties (phase velocity and attenuation) differ significantly under various wettability conditions.
• Increased hydrophobicity leads to higher phase velocity.
• A distinct attenuation peak in the high-frequency range is observed with increasing hydrophobicity.

Conclusions:

• Slip length is a crucial parameter for modeling elastic waves in wettable and non-wettable porous media.
• Wettability directly influences the acoustical response of saturated porous materials.
• The study provides a framework for predicting wave behavior based on surface wettability.