H034-0006
Spontaneous Imbibition Dynamics of Liquids in Homogeneous Nanoporous Media: Experiment and Theory

Tuesday, 8 December 2020
Poster
Bin Pan1, Christopher Clarkson2, Marwa Atwa3, Xia Tong3, Chris Debuhr2, Amin Ghanizadeh2 and Viola I Birss3, (1)University of Calgary, Department of Chemical and Petroleum Engineering, Calgary, AB, Canada, (2)University of Calgary, Department of Geoscience, Calgary, AB, Canada, (3)University of Calgary, Department of Chemistry, Calgary, AB, Canada
Abstract:
The dynamics of spontaneous imbibition in low-permeability unconventional reservoirs is still poorly understood, primarily due to the chemical and structural complexities of natural shale/tight rocks. To attempt to overcome these challenges, a novel nanoporous carbon scaffold (NCS) is used as a model material in this work. The NCS has tunable pore diameters (PD: 12, 22, 50 and 85 nm) and pore throat diameters (PTD: 7, 12,16 and 35 nm), an ordered, three-dimensionally interconnected structure, and controllable wettability. Herein, the effects of PD, PTD, evaporation and the presence of surfactant on spontaneous imbibition dynamics are examined. A modified Lucas-Washburn (L-W) equation is developed to describe the corresponding dynamics and to predict hydraulic radius and water advancing contact angle in nanoporous media.

For low-volatility liquids, e.g., aqueous liquids (deionized water and 1 M KCl brine) at high humidity (> 70%), and high viscosity (5 cSt and 10 cSt) silicone oil, a linear relationship between spontaneous imbibition height and square root of time is observed, in agreement with the modified L-W equation. NCS samples with larger PD and PTD cause a faster imbibition. Addition of 1 wt% Dodecyltrimethylammonium bromide (DTAB) to 1 M KCl brine increases the imbibition rate, but this is suppressed with a pore size decrease.

In contrast, for high-volatility liquids, e.g., aqueous fluids at low humidity (35% ~ 45%) and low viscosity (1 cSt and 1.5 cSt) silicone oil, a significant deviation from the linear relationship between spontaneous imbibition height and square root of time is found at longer times. The modified L-W equation is further developed to include the effect of evaporation, which can describe the corresponding dynamics correctly.

These findings shed light on the fundamental understanding of the dynamics of imbibition at the nanoscale and provide guidance on water infiltration in soil, unconventional oil recovery and electrochemical device design.

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