Christopher Zahasky

Christopher Zahasky
Assistant Professor
Experimental hydrogeology, Contaminant transport, Reservoir engineering, Energy resources engineering
Email: czahasky@wisc.edu
Phone: 608-265-4274
Office: 419 Weeks Hall

Research

My research focuses on using experimental, analytical, and numerical methods to improve our understanding of fundamental physics and mechanisms of fluid, gas, and solute transport in heterogeneous porous and fractured media.

Due to the fundamental nature of this approach, and the ubiquity of fluid transport in porous media, this work has important applications across a range of important environmental and geological processes including contaminant migration in the vadose zone, fluid flow through fractured systems, colloid transport in the subsurface, and carbon dioxide transport and immobilization in carbon storage projects.

Current Projects

  • Contaminant transport during spontaneous imbibition: Experimental observations from positron emission tomography (PET) scans are used to constrain a coupled numerical model to understand solute migration during multiphase flow displacement.
  • Evaluation of pore network model predictions of continuum multiphase flow heterogeneity by comparison with high resolution experimental observations: Pore network models are powerful tools for understanding multiphase flow at the pore scale as they can achieve orders of magnitude faster computational times than direct simulation methods. This computational advantage potentially enables pore network models to describe and predict Darcy-scale multiphase flow heterogeneity. In this project, high resolution X-ray micro-computed tomography images of multiphase flow experiments are used to assess the validity of pore network model multiphase characteristic predictions
  • Spatial and temporal quantification of nanoparticle transport in geologic porous media: Silica nanoparticles exist in the environment due to increasing utilization in consumer products, lubricants, and production during certain manufacturing and combustion processes. In addition to their undesirable—and potentially hazardous presence in the environment—nanoparticles are rapidly emerging as a tool for fluid flow alteration in the subsurface, and for removal of organic pollutants, toxic metals, uranium, and phosphate from contaminated water. Nanoparticle transport and retention in simplified porous media has been well constrained and mechanistically described. However, we lack quantitative understanding and prediction in dynamic non-ideal systems where nanoparticles are influenced by a complex combination of inconsistent hydrodynamic forces and physical and chemical heterogeneity. The goal of this project is to use novel experimental methods to develop a better understanding of in situ nanoparticle transport in geologic media.

More details can be found here.

Publications

Google Scholar | ORCID | Preprints and Postprints

Teaching

I will be teaching the following classes in the coming year, both of which are cross-listed with UW-Madison’s Geologic Engineering (GLE)

SPRING 2020:

  • GEOS / GLE-629: Contaminant Hydrogeology

FALL 2020:

  • GEOS / GLE-627: Hydrogeology (joint with Michael Cardiff)