| Title | Fault and natural fracture control on upward fluid migration: insights from a shale gas play in the St. Lawrence Platform, Canada |
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| Author | Ladevèze, P; Rivard, C ; Lavoie, D; Séjourné, S; Lefebvre, R; Bordeleau,
G |
| Source | Hydrogeology Journal vol. 27, issue 1, 2018 p. 121-143, https://doi.org/10.1007/s10040-018-1856-5  Open Access |
| Image |  |
| Year | 2018 |
| Alt Series | Natural Resources Canada, Contribution Series 20170286 |
| Publisher | Springer |
| Document | serial |
| Lang. | English |
| Media | paper; on-line; digital |
| File format | pdf; html |
| Province | Quebec |
| NTS | 21L/12 |
| Area | Saint-Édouard; St. Lawrence River |
| Lat/Long WENS | -72.0000 -71.5000 46.7500 46.5000 |
| Subjects | fossil fuels; structural geology; environmental geology; hydrogeology; geophysics; Science and Technology; Nature and Environment; petroleum resources; petroleum exploration; hydrocarbon recovery;
hydrocarbons; gas; reservoirs; fluid migration; fluid flow; models; hydrodynamics; groundwater resources; aquifers; groundwater flow; groundwater pollution; bedrock geology; structural features; faults; faults, thrust; faults, normal; fault zones;
fractures; folds; synclines; anticlines; lithology; sedimentary rocks; shales; siltstones; geophysical interpretations; geophysical logging; hydraulic analyses; porosity; permeability; hydraulic conductivity; anisotropy; observation wells; gas wells;
pressure; St. Lawrence Platform; Utica Shale; Logan's Line; Aston Fault; Chambly-Fortierville Syncline; Rivière Jacques-Cartier Fault; Queenston Group; Lorraine Group; Pontgavré Formation; Nicolet Formation; Sainte-Rosalie Group; Lotbinière
Formation; Les Fonds Formation; Trenton Group; Black River Group; Chazy Group; Beekmantown Group; Potsdam Group; Grenville Province; Phanerozoic; Paleozoic; Ordovician; Cambrian; Precambrian; Proterozoic |
| Illustrations | location maps; geoscientific sketch maps; cross-sections; photographs; 3-D models; tables; bar graphs; profiles; geophysical logs; geophysical images; 3-D diagrams; models |
| Program | Environmental
Geoscience Shale Gas - groundwater |
| Released | 2018 09 18 |
| Abstract | Environmental concerns have been raised with respect to shale gas exploration and production, especially in eastern Canada and northeastern United States. One of the major public concerns has been the
contamination of freshwater resources. This paper focuses on the investigation of possible fluid upward migration through structural features in the intermediate zone (IZ), located between a deep shale-gas reservoir and shallow aquifers. The approach
provides insights into how such an investigation can be done when few data are available at depth. The study area is located in the shale-dominated succession of the St. Lawrence Platform (eastern Canada), where the Utica Shale was explored for
natural gas between 2006 and 2010. Detailed analyses were carried out on both shallow and deep geophysical log datasets providing the structural attributes and preliminary estimates of the hydraulic properties of faults and fractures. Results show
that the active groundwater flow zone is located within the upper 60 m of bedrock, where fractures are well interconnected. Fractures from one set were found to be frequently open in the IZ and reservoir, providing a poorly connected network. The
fault zones are here described as combined conduit-barrier systems with sealed cores and some open fractures in the damage zones. Although no direct hydraulic data were available at depth, the possibility that the fracture network or fault zones act
as large-scale flow pathways seems very unlikely. A conceptual model of the fluid flow patterns, summarizing the current understanding of the system hydrodynamics, is also presented. |
| Summary | (Plain Language Summary, not published)
Strong environmental concerns have been raised relative to shale gas exploration and production, especially in eastern Canada. One of the major public
concerns has been the contamination of fresh water resources. This paper focuses on the investigation of possible fluid flow pathways between a deep shale gas reservoir and shallow aquifers through structural features, which could impact groundwater
quality. The study area is located in the St. Lawrence Platform, where the Utica Shale was explored between 2006 and 2010. Although no hydraulic data were available at depth, the possibility that the fracture network or fault zones act as large-scale
flow pathways seems very unlikely based on field observations, well logs interpretation and conceptual models both for the fracture network and fluid flow patterns. Results presented in this paper provide insights into how potential environmental
impacts of shale gas development on aquifers through upward migration can be investigated, when there is little available data at depth. |
| GEOSCAN ID | 306282 |
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