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Pore-scale investigation on stress-dependent characteristics of granular packs and the impact of pore deformation on fluid distribution

Geofluids

Torrealba, V.A.; Karpyn, Z.T.; Yoon, Hongkyu Y.; Klise, Katherine A.; Crandall, D.

Understanding the effect of changing stress conditions on multiphase flow in porous media is of fundamental importance for many subsurface activities including enhanced oil recovery, water drawdown from aquifers, soil confinement, and geologic carbon storage. Geomechanical properties of complex porous systems are dynamically linked to flow conditions, but their feedback relationship is often oversimplified due to the difficulty of representing pore-scale stress deformation and multiphase flow characteristics in high fidelity. In this work, we performed pore-scale experiments of single- and multiphase flow through bead packs at different confining pressure conditions to elucidate compaction-dependent characteristics of granular packs and their impact on fluid flow. A series of drainage and imbibition cycles were conducted on a water-wet, soda-lime glass bead pack under varying confining stress conditions. Simultaneously, X-ray micro-CT was used to visualize and quantify the degree of deformation and fluid distribution corresponding with each stress condition and injection cycle. Micro-CT images were segmented using a gradient-based method to identify fluids (e.g., oil and water), and solid phase redistribution throughout the different experimental stages. Changes in porosity, tortuosity, and specific surface area were quantified as a function of applied confining pressure. Results demonstrate varying degrees of sensitivity of these properties to confining pressure, which suggests that caution must be taken when considering scalability of these properties for practical modeling purposes. Changes in capillary number with confining pressure are attributed to the increase in pore velocity as a result of pore contraction. However, this increase in pore velocity was found to have a marginal impact on average phase trapping at different confining pressures.

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TYPE Journal Article YEAR 2016
ScopusOSTIDOI

Geologic Carbon Storage and Fracture Fate: Chemistry Heterogeneity Models and What to do with it all

Dewers, Thomas D.; Rinehart, Alex R.; Major, Jonathan R.; Lee, Sanghyun L.; Reber, Jacqueline R.; Choens, Robert C.; Feldman, Joshua D.; Eichhubl, Peter E.; Wheeler, Mary W.; Ganis, Ben G.; Hayman, Nick H.; Ilgen, Anastasia G.; Prodanovic, Masa P.; Bishop, Joseph E.; Balhoff, Matt B.; Espinoza, Nicolas E.; Martinez, Mario J.; Yoon, Hongkyu Y.

Abstract not provided.

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TYPE Conference Poster YEAR 2016
OSTI

Metabolism-Induced CaCO3 Biomineralization during Reactive Transport in a Micromodel: Implications for Porosity Alteration

Environmental Science and Technology

Singh, Rajveer; Yoon, Hongkyu Y.; Sanford, Robert A.; Katz, Lynn; Fouke, Bruce W.; Werth, Charles J.

The ability of Pseudomonas stutzeri strain DCP-Ps1 to drive CaCO3 biomineralization has been investigated in a microfluidic flowcell (i.e., micromodel) that simulates subsurface porous media. Results indicate that CaCO3 precipitation occurs during NO3- reduction with a maximum saturation index (SIcalcite) of ∼1.56, but not when NO3- was removed, inactive biomass remained, and pH and alkalinity were adjusted to SIcalcite ∼ 1.56. CaCO3 precipitation was promoted by metabolically active cultures of strain DCP-Ps1, which at similar values of SIcalcite, have a more negative surface charge than inactive strain DCP-Ps1. A two-stage NO3- reduction (NO3- → NO2- → N2) pore-scale reactive transport model was used to evaluate denitrification kinetics, which was observed in the micromodel as upper (NO3- reduction) and lower (NO2- reduction) horizontal zones of biomass growth with CaCO3 precipitation exclusively in the lower zone. Model results are consistent with two biomass growth regions and indicate that precipitation occurred in the lower zone because the largest increase in pH and alkalinity is associated with NO2- reduction. CaCO3 precipitates typically occupied the entire vertical depth of pores and impacted porosity, permeability, and flow. This study provides a framework for incorporating microbial activity in biogeochemistry models, which often base biomineralization only on SI (caused by biotic or abiotic reactions) and, thereby, underpredict the extent of this complex process. These results have wide-ranging implications for understanding reactive transport in relevance to groundwater remediation, CO2 sequestration, and enhanced oil recovery.

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TYPE Journal Article YEAR 2015
ScopusOSTIDOI
Results 151–175 of 246
Results 151–175 of 246