| Title | Baseline near-surface bedrock and groundwater geochemical data prior to shale gas development - Preliminary data from southern Quebec |
| Author | Lavoie, D; Mort, A; Haeri Ardakani, O; Sanei, H; Bordeleau, G; Rivard, C; Aznar, J C |
| Source | Geological Association of Canada-Mineralogical Association of Canada, Joint Annual Meeting, Abstracts Volume vol. 37, 2014 p. 154 |
| Year | 2014 |
| Alt Series | Earth Sciences Sector, Contribution Series 20130415 |
| Publisher | Geological Association of Canada - Mineralogical Association of Canada |
| Meeting | Gerological Association of Canada - Mineralogical Association of Canada annual meeting; Fredericton; CA; May 21-23, 2014 |
| Document | serial |
| Lang. | English |
| Media | paper; on-line; digital |
| File format | pdf |
| Province | Quebec |
| NTS | 21L; 31H; 31I |
| Area | St. Lawrence Platform |
| Lat/Long WENS | -75.0000 -71.0000 46.7500 45.0000 |
| Subjects | fossil fuels; geochemistry; hydrogeology; bedrock geology; groundwater geochemistry; groundwater; hydrocarbons; hydrocarbon potential; methane; Uthica Shale; Lorraine Group; Paleozoic;
Ordovician |
| |
| Program | Shale Gas - groundwater, Environmental
Geoscience |
| Links | Online - En ligne
|
| Abstract | In southern Quebec, from 2006 to 2010, drilling and fracking results have shown that the Upper Ordovician Utica Shale is a potential shale gas producer. In 2010, exploration came to a halt pending an
environmental review of all issues related to shale gas exploration and development. The Geological Survey of Canada has initiated a detailed evaluation of shallow and deep sub-surface conditions (geology, hydrogeology, geochemistry, geophysics and
geomechanic) at a specific site southwest of Quebec City where one shale gas well targeting the Utica Shale has been drilled and fracked. During the summer and fall of 2013, twenty-five private water wells were sampled and 4 shallow (50 m) wells
were drilled, cored and sampled for water chemistry and rock organic geochemistry. In addition, 250 sites were sampled for pore-space radon and hydrocarbons in soils.
The shallow bedrock geology is dominated by Upper Ordovician shales and
sandstones of the Lorraine Group, the cap rock of the Utica Shale present at roughly 2 km deep in the subsurface. Rock-Eval and organic matter reflectance results from the organic matter rich Lorraine shales suggest that thermal maturity increases
southerly from oil to condensate windows. GC and GC-MS analyses of core extracts document the presence of low but detectable concentrations of C1 to C20 hydrocarbons.
Most water samples have significant concentrations of dissolved hydrocarbons
including mostly methane, as well as ethane and propane in a few wells. The presence of dissolved hydrocarbons in groundwater is fairly well established in southern Quebec, although their source (biogenic versus thermogenic) remains ambiguous. The
presence of dissolved propane indicates that some of the hydrocarbons are thermogenic in origin. Gas wetness and isotopic ratios (?13C, ?2H) of methane suggest mixed thermogenic and biogenic origin. Areas with elevated radon, methane, ethane and
butane in soils are located close of the Appalachians ' St. Lawrence Platform contact, a sector with high concentrations of hydrocarbons dissolved in groundwater. |
| Summary | (Plain Language Summary, not published)
This abstract will present preliminary geochemical data in groundwater, soils and bedrock that were gathered up to now in this project (Environmental
Geoscience and Geoscience for New Energy Supply programs). One of the goals of the study is to identify the source of gas present in groundwater in the St. Edouard de Lotbinière (65 km SW of Quebec City). Some preliminary ideas are considered but
without certitude so far. This will be explained in the presentation |
| GEOSCAN ID | 293521 |
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