A risk assessment tool applied to the study of shale gas resources

Forecasting concentrations of organic chemicals in the vadose zone caused by spills of hydraulic fracturing wastewater

“…Here we provide new approaches for the assessment of the environmental, safety and health risks associated with the extraction of nonconventional fossil fuel resources by hydraulic fracturing [Veiguela et al, 2016] at local and larger scales. The model described herein offers a valuable tool for the management of shale gas exploitations and is expected to find further applications in similar scenarios.…”

A method for screening groundwater vulnerability from subsurface hydrocarbon extraction practices

“…A risk assessment tool developed for shale gas resources by Veiguela et al (2016), based on a framework originally developed for geologic CO2 storage siting (Oldenburg, 2008), took a similar approach to this method. It includes factor weightings, attribute property ratings and certainty, although final outputs are calculated using normalised weightings which assumes each attribute category (depth, seal formation, ground stability, target rock, surface characteristics, nearby wells and pollutants) have equal influence.…”

“…It includes factor weightings, attribute property ratings and certainty, although final outputs are calculated using normalised weightings which assumes each attribute category (depth, seal formation, ground stability, target rock, surface characteristics, nearby wells and pollutants) have equal influence. The parameters considered by Veiguela et al (2016) are more wide-ranging although technological aspects are specifically designed for shale gas operations such that comparisons cannot be made for different technologies. The main geological parameters (separation distance and geological flow paths) accounted for are in agreement, although Veiguela et al (2016) have included fewer geological and hydrogeological factors.…”

“…The parameters considered by Veiguela et al (2016) are more wide-ranging although technological aspects are specifically designed for shale gas operations such that comparisons cannot be made for different technologies. The main geological parameters (separation distance and geological flow paths) accounted for are in agreement, although Veiguela et al (2016) have included fewer geological and hydrogeological factors. For example, they identify only a single seal formation in the intervening thickness between the target and the aquifer which does not take into account the impact of multiple barriers, the overall influence of low permeability units (Freeze and Cherry, 1979) and the impact of the whole geological sequence in contributing to the subsurface risk profile.…”

“…Unlike other vulnerability methods, the 3D nature of this problem, and limited data availability in most deep subsurface locations, does not allow for the production of simple maps, and therefore the screening at this stage should primarily be used for site-specific screenings. Veiguela et al (2016) developed a tool for shale gas resources to assess risks to health, safety and the environment based on a tool initially developed by Oldenburg (2008) for geological CO2 storage. While similar in approach to the screening described here, each focuses on a single technology thus does not allow for comparison between technologies.…”