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TitleThe Lower-Middle Devonian of Mackenzie River Corridor: sequence-stratigraphic updates from core studies
 
AuthorKabanov, P B
SourceProceedings of GeoConvention 2013; 2013 p. 1-4
LinksOnline - En ligne
Image
Year2013
Alt SeriesEarth Sciences Sector, Contribution Series 20130109
PublisherCSPG
MeetingGeoConvention 2013; Calgary; CA; May 6-10, 2013
Documentserial
Lang.English
Mediaon-line; digital
File formatpdf
ProvinceNorthwest Territories
NTS106N; 106O; 107A/03; 107A/04; 107A/05; 107A/06
AreaMackenzie River
Lat/Long WENS-134.0000 -130.0000 68.5000 67.0000
Subjectsfossil fuels; stratigraphy; Lower Devonian; Middle Devonian; oil shows; hydrocarbon potential; hydrocarbons; shales; oil wells; Kugaluk N-02; Wolverine H-34; Tenlen A-73; Paleozoic; Devonian
Illustrationsstratigraphic columns; photographs
ProgramGEM: Geo-mapping for Energy and Minerals Mackenzie Delta and Corridor
AbstractThe Lower-Middle Devonian of central and northern Mackenzie River Corridor contains one giant conventional play (Norman Wells) and numerous shows in breccias, dolostones and limestones. This succession also hosts the major Paleozoic prospect for shale gas (Muskwa-Canol Member) added by significant prospects in Bluefish and Headless shales (Hannigan et al., 2009). Long-standing uncertainties in formation relationships and sequence boundaries urge improvements in regional sequence-stratigraphic framework as a critical step towards investments into exploration of both conventional and non-conventional hydrocarbon resources. One of key steps is revisiting wells with representative core coverage such as Kugaluk N-02 of Inuvik Area (Fig. 1).
Figure 1: Upper Landry - Hume interval in Kugaluk N-02 well with complete core coverage and its correlation with two other wells; note three upper subaerial disconformities in Landry Fm.
Methods and materials
The studied core (over 600 m in total) comes from the wells Kugaluk N-02, Maida Ck F-57, Norman Wells P32X, Devo Ck P45, and Imperial Bear Island R34X, all drilled in 1960-90ies. This core is housed at the NEB Core and Sample Repository in Calgary. Adequate manifestation of sub-mm scale structures (Figs. 2 & 3) was attained by sanding core with 35 µm calcium carbide powder (grit 400) and subsequent etching by 10% HCl for 1-2 sec. A range of methods (Rock-Eval, xygen isotopes, thin sections, and ESEM-WDS observations) are being applied to further understanding of facies patterns, sequence surfaces and packages.
Results
Examination of continuous core from Kugaluk N-02 (Fig. 1; northern Anderson Plain) and representative cores from Norman Wells area provide new insight into facies patterns and boundaries of Landry, Hume, Bluefish, Hare Indian, Ramparts, and Canol formations. Numerous previously unknown subaerial disconformities bounding meter-scale peritidal cycles are discovered within Landry, whereas Landry/Headless, Headless/Hume, and Hume/Canol boundaries appear conformable. The Landry succession is a cyclic repetition of shallow subtidal limestones, thick tidal-flat laminites, and palustrine micritic limestones. The Landry Fm. (948-1164 m MD) contains 35 simple and composite subaerial disconformities. Most mature vadose alteration profiles extend to depths of 3-4 meters below disconformity surfaces. Interpreted from Landry succession amplitudes of sea-level fluctuations should have exceeded 10 m. This spectacular cyclic pattern does not have vivid log signatures, but caliper seems to be sensitive to karst breccias (Fig. 1). The Hume Fm. at Kugaluk N-02 is a lower ramp argillaceous and apparently conformable limestone grading down into even deeper water calcareous shales of the Headless Mmbr. (tempestites, Zoophycos and Chondrites traces). In the Norman Wells area, an abrupt top of the Ramparts limestone is a ¿drowning disconformity¿ with no evidence for shoaling or subaerial exposure (Fig. 3C; Norman Wells P32X). In the Imperial Bear Island R34X, the 54 m long core penetrating the upper Hare Indian Fm., Carcajou Mmbr., and the basal Ramparts Fm., records fully conformable succession with very gradual upward trend of shallowing and cleaning (argillaceous to non-argillaceous limestones). Data presented here concur to the model of the Ramparts/Kee Scarp carbonate platform evolution and its stratigraphic relationship to the Canol black shale published by Muir et al. (1984). Certain modifications to the regional sequence stratigraphic framework will likely come up with new data arriving.
Acknowledgements
This work is part of the Mackenzie Delta and Corridor project (EGM-003, GEM Program). I am grateful to Robert MacNaughton for promoting this study and Barry C. Richards for reviewing this paper.
Figure 2: Shale units and their contacts with limestones: (A) Apparently conformable contact of Hume limestone and Canol/Bluefish black shale in Kugaluk N-02 (contact arrowed); (B) laminated calcareous shale of Headless Member (distal tempestite) deposited in lower ramp setting; (C) Ramparts (Kee Scarp) - Canol contact in Norman Wells P32X directional well; yellow arrow shows stratigraphic up.
Figure 3: Disconformities (A, B; arrowed) and palustrine limestone (C) in Landry Limestone of Kaugaluk N-02: (A) Stylolitized karst breccia with extensive quasicoatings (qc) and geopetal shale in caverns, some core in top is missing, 978.3 m MD; (B) An erosional surface over a finely karstified calcimudstone (vugs may have developed upon primary fenestrae), 1062.5 m MD; (C) A microbrecciated non-marine calcimudstone with rounded glaebules, chambers, and probably rootlet penetrations (rh), 1058.0 m MD.
Summary(Plain Language Summary, not published)
The Lower-Middle Devonian of central and northern Mackenzie River Corridor contains one giant conventional play (Norman Wells) and numerous shows in breccias, dolostones and limestones. This succession also hosts the major Paleozoic prospect for shale gas (Muskwa-Canol Member) added by significant prospects in Bluefish and Headless shales (Hannigan et al., 2009). Long-standing uncertainties in formation relationships and sequence boundaries urge improvements in regional sequence-stratigraphic framework as a critical step towards investments into exploration of both conventional and non-conventional hydrocarbon resources. One of key steps is revisiting wells with representative core coverage. This presentation reports progress in core study from wells Kugaluk N-02, Maida Ck F-57, Norman Wells P32X, Devo Ck P45, and Imperial Bear Island R34X.
GEOSCAN ID292731

 
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