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TitleGeometry and regional significance of joint sets in the Ordovician-Silurian Anticosti Basin: new insights from fracture mapping
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AuthorPinet, N; Brake, V; Lavoie, D
SourceGeological Survey of Canada, Open File 7752, 2015, 25 pages, https://doi.org/10.4095/295982
Year2015
PublisherNatural Resources Canada
Documentopen file
Lang.English
Mediaon-line; digital
File formatpdf
ProvinceEastern offshore region
NTS12E; 12F/04; 12F/05; 22H/16; 22L/03; 22L/04
AreaGulf of St. Lawrence; Havre-Saint-Pierre; Mingan Islands; Anticosti Island
Lat/Long WENS-65.0000 -61.5000 50.2500 49.0000
Subjectsstratigraphy; structural geology; fracture analyses; fractures; joint patterns; joints; structural analyses; structural features; structural interpretations; sedimentary rocks; stress analyses; stress patterns; stress distribution; Anticosti Basin; Paleozoic; Silurian; Ordovician
Illustrationslocation maps; photographs; stratigraphic columns; rose diagrams; histograms
ProgramGeoscience for New Energy Supply (GNES) - Program Corrdination, Geoscience for New Energy Supply (GNES)
Released2015 04 01
AbstractTensile opening-mode fractures (or joints) intensively dissect nearly flat-lying Lower Ordovician to lower Silurian strata in the northern part of the Anticosti Basin. Fracture mapping near Havre-Saint-Pierre, on the Mingan Islands and on Anticosti Island indicates that the two predominant joint sets are nearly orthogonal and trend ~ N100 and ~N10. For the majority of the studied sites, the ~N100 joints are the older and most continuous, suggesting that they form a systematic set of fractures that likely extend to a significant depth. The median spacing of the ~N100 systematic joint set is approximately 1 m and is partly controlled by the mechanical characteristics of the fractured bed. Some joints exhibit significant horizontal and vertical continuity and are locally concentrated in structural corridors, suggesting that they may influence subsurface fluid flow if open at depth. Systematic fractures are interpreted to have formed in a forebulge setting during an episode of local extension.
Summary(Plain Language Summary, not published)
Anticosti Island is presently the focus of unconventional petroleum exploration. In this context, it is important to characterize the factors that may influence fluid flow in the subsurface. Among these factors, fractures are an essential consideration because they may act as fluid migration pathways and affect the seal rock integrity. This study presents a characterization of fractures observed on Anticosti Island and in the Havre-Saint-Pierre/Mingan area. Fractures dissect nearly flat-lying strata and include two predominant sets trending ~ N100 and ~N10 that likely extend to a significant depth. The median spacing of the main fracture set is approximately 1 m and is partly strata-controlled. Some fractures exhibit significant continuity both horizontally and vertically and are locally concentrated in structural corridors, suggesting that they may influence subsurface fluid flow if they exhibit significant aperture at depth, a parameter that remains unconstrained after this study.
GEOSCAN ID295982