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TitleAssessing groundwater vulnerability to shale gas activities in the Sussex area, southern New Brunswick / Évaluation de la vulnérabilité des aquifères à l'exploitation du gaz de shale dans la région de Sussex, dans le sud du Nouveau-Brunswick
DownloadDownload (whole publication)
AuthorRivard, C
SourcePublic presentations of May 21st, 2019: Environmental Geoscience Program, current status of research projects (phase 2014-2019); by Jacob, N; Parsons, M; Rivard, C; Savard, M M; Larmagnat, S; Outridge, P M; White, D; Kao, H; Lintern, G; Geological Survey of Canada, Scientific Presentation 104, 2019 p. 19-34, (Open Access)
PublisherNatural Resources Canada
Lang.English; French
Mediaon-line; digital
RelatedThis publication is contained in Jacob, N; Parsons, M; Rivard, C; Savard, M M; Larmagnat, S; Outridge, P M; White, D; Kao, H; Lintern, G; (2019). Public presentations of May 21st, 2019: Environmental Geoscience Program, current status of research projects (phase 2014-2019), Geological Survey of Canada, Scientific Presentation no. 104
File formatpdf (Adobe® Reader®)
ProvinceNew Brunswick
NTS21H/10; 21H/11; 21H/12; 21H/13; 21H/14; 21H/15; 21I/02; 21I/03; 21I/04
Lat/Long WENS -65.5842 -64.9228 46.0244 45.5872
Subjectsenvironmental geology; hydrogeology; geochemistry; fossil fuels; geophysics; structural geology; Nature and Environment; Science and Technology; Government and Politics; Economics and Industry; environmental studies; environmental impacts; groundwater resources; aquifers; groundwater pollution; groundwater geochemistry; water quality; flow regimes; petroleum resources; petroleum industry; hydrocarbons; gas; methane; hydrocarbon recovery; hydrocarbon migration; flow regimes; hydraulic fracturing; bedrock geology; structural features; fractures; lithology; sedimentary rocks; shales; sandstones; evaporites; observation wells; reservoir rocks; field work; structural interpretations; boreholes; geophysical logging; organic geochemistry; hydrocarbon maturation; modelling; Environmental Geoscience Program (EGP); McCully Gas Field; Elgin Gas Field; environmental impact assessment; anthropogenic impacts; shale gas; environmental baseline studies; monitoring; Phanerozoic; Paleozoic; Carboniferous
Illustrationslocation maps; schematic cross-sections; cross-sections; photographs; models; geophysical logs; plots; geoscientific sketch maps; bar graphs
ProgramEnvironmental Geoscience, Program Management
Released2019 10 10
AbstractA project studying potential hydrocarbon migration through natural pathways or fracking-induced fractures from deep (~2 km) Carboniferous shale or tight sand units to shallow aquifers was initiated in 2015 in the Sussex area, southern New Brunswick. The study area includes the McCully gas field that has been in production since 2001 and the Elgin field that is investigated for its condensate potential. Because the intermediate zone (IZ) located between shallow aquifers and units targeted for hydrocarbon production is poorly characterized, this project relies on the integration of data from different earth science disciplines, including geology, geophysics, geomechanics, hydrogeology and water and rock geochemistry. Fieldwork in 2018-2019 included the drilling of two observation wells, borehole geophysics, and groundwater monitoring.
Data collected during this 4-year project and their interpretation provided no evidence for the presence of large-scale connections between gas reservoirs and shallow aquifers in this study area. On the contrary, the IZ seems to provide an efficient barrier protecting the shallow aquifer from the potential upward migration of fluids originating from deep hydrocarbon reservoirs. This conclusion integrates the interpretations derived from the geomechanical study, from the geophysical and geological analyses of the structural context and from the geochemical baseline study. Although large-scale upward fluid migration is considered very unlikely, evidence of some upward migration over a few hundred meters was found based on old, evolved groundwater observed in two of the shallow (50 m) observation wells. This water indicated a contribution from evaporites from a relatively shallow salt structure (~250-300 m), whose chemical components are assumed to have been transferred to the active groundwater flow zone by diffusion. Also, regular monitoring of several shallow wells helped ascertain the source of methane in groundwater when individual samples provided ambiguous results.