Non-Darcy interfacial dynamics of air-water two-phase flow in rough fractures under drainage conditions.

Two-phase flow interfacial dynamics in rough fractures is fundamental to understanding fluid transport in fractured media. The Haines jump of non-Darcy flow in porous media has been investigated at pore scales, but its fundamental processes in rough fractures remain unclear. In this study, the micron-scale Haines jump of the air-water interface in rough fractures was investigated under drainage conditions, with the air-water interface tracked using dyed water and an imaging system.

Pressure buildup and brine migration during CO2 storage in multilayered aquifers.

Carbon dioxide injection into deep saline formations may induce large-scale pressure increases and migration of native fluid. Local high-conductivity features, such as improperly abandoned wells or conductive faults, could act as conduits for focused leakage of brine into shallow groundwater resources. Pressurized brine can also be pushed into overlying/underlying formations because of diffuse leakage through low-permeability aquitards, which occur over large areas and may allow for effective pressure bleed-off in the storage reservoirs.

Modeling basin- and plume-scale processes of CO2 storage for full-scale deployment.

Integrated modeling of basin- and plume-scale processes induced by full-scale deployment of CO(2) storage was applied to the Mt. Simon Aquifer in the Illinois Basin. A three-dimensional mesh was generated with local refinement around 20 injection sites, with approximately 30 km spacing.

Field evidence of biodegradation of N-Nitrosodimethylamine (NDMA) in groundwater with incidental and active recycled water recharge.

Biodegradation of N-Nitrosodimethylamine (NDMA) has been found through laboratory incubation in unsaturated and saturated soil samples under both aerobic and anaerobic conditions. However, direct field evidence of in situ biodegradation in groundwater is very limited. This research aimed to evaluate biodegradation of NDMA in a large-scale groundwater system receiving recycled water as incidental and active recharge.

Field-scale effective matrix diffusion coefficient for fractured rock: results from literature survey.

Matrix diffusion is an important mechanism for solute transport in fractured rock. We recently conducted a literature survey on the effective matrix diffusion coefficient, D(m)(e), a key parameter for describing matrix diffusion processes at the field scale. Forty field tracer tests at 15 fractured geologic sites were surveyed and selected for the study, based on data availability and quality.

Analysis of a mesoscale infiltration and water seepage test in unsaturated fractured rock: Spatial variabilities and discrete fracture patterns.

A mesoscale (21 m in flow distance) infiltration and seepage test was recently conducted in a deep, unsaturated fractured rock system at the crossover point of two underground tunnels. Water was released from a 3 mx4 m infiltration plot on the floor of an alcove in the upper tunnel, and seepage was collected from the ceiling of a niche in the lower tunnel. Significant temporal and (particularly) spatial variabilities were observed in both measured infiltration and seepage rates.

Flow and transport in unsaturated fractured rock: effects of multiscale heterogeneity of hydrogeologic properties.

The heterogeneity of hydrogeologic properties at different scales may have different effects on flow and transport processes in a subsurface system. A model for the unsaturated zone of Yucca Mountain, Nevada, is developed to represent complex heterogeneity at two different scales: (1) layer scale corresponding to geologic layering and (2) local scale. The layer-scale hydrogeologic properties are obtained using inverse modeling, based on the available measurements collected from the Yucca Mountain site.