This project examines the impact of hydraulic fracturing fluid chemicals on the mobilization of toxic elements (e.g. As, U, Ba) under rerservoir temperature and pressure conditions. We are analyzing the release of these constintuents from organic-rich shales through use of batch and flow-through reactor apparatuses. Our current focus is on the Utica-Collingwood shale gas reservoir in the Michigan Basin, which is an emerging shale gas play in Michigan. This project is funded by NSF (grant no. 1336719) and both Wenjia Fan and Letian Zhou are working on this project.

View a recorded presenation discussing the sustainability challenges of shale gas development 

This study seeks to gain a fundamental understanding of the mechanism controlling shale wettability change during the shut-in period that leads to reduced flowback and, by inference, enhanced gas production from shale gas reservoirs. Current work related to this project includes investigating the role of mixed charge surfactant adsorption on shales in altering shale wettability through us of contact angle and surface tension measurements. Atomic force microscopy is also being used to characterize surface charge and mineral phase distribution at the sub-micron scale to explore surfactant adsorption mechanisms on heterogeneous, mixed charge shale materials. We have also recently initiated a neutron imaging study at ORNL to investigate the role of mixed charge surfactants in controlling the rate of water imbibition into shale fractures. To date, we have utilized neutron CT imaging to quantify the rate of water uptake into shale fractures. Future neutron studies include small angle neutron scattering experiments to determine methane accessibility to sub-250 nm shale pores after exposure to a range of surfactant concentrations.

The overall objective of the this project is to advance the scientific and technical understanding of microstructure and surface chemistry impacts on the flow and mineralization of CO2 injected into fractured basalt. This objective will be pursued through an approach that integrates bench-scale CO2-water-rock testing, geomechanical and geochemical characterization of rock cores, and advanced in situ characterization of the evolution of fracture structure and carbon trapping mechanisms. Basalt samples from relevant formations will be used together with synthetic basalts that are more reproducible specimens for systematic evaluation of the effects of specific variables on CO2 behavior. Laboratory experiments will evaluate the extent of carbon sequestration and the distribution of trapping among different mechanisms under both static (i.e. no-flow) conditions that simulate dead-end fractures and dynamic (i.e. advective fluid flow) conditions that simulate major fracture flow paths. This project will be conducted in collaboration with colleagues from Washington University in St. Louis. It is funded by the U.S. Department of Energy National Energy Technology Laboratory.