This study presents the first shale gas appraisal of Devonian-Mississippian shale strata in Yukon’s Liard basin. Assessed volumes of 68 Tcf gas-in-place and 7.6 Tcf marketable gas are contained within two shale plays identified from an integrated wireline log and geochemical evaluation: the Devonian (Givetian-Frasnian) Horn River shale and the Devonian-Mississippian (Famennian-Tournaisian) Exshaw-Patry shale. Average burial depths of 3018 mTVD and net pay thicknesses of 73 m for the Horn River, and 2688 mTVD and 89 m for the Exshaw-Patry plays are interpreted. Both plays are dominated by black, organic-rich, siliceous mudstones, and exhibit: elevated TOC contents (0.6-6.9 wt %); maturities within or past the dry gas window (2.1-4.6 %Ro); very high biogenic silica proportions (averaging 80.2-90.3%); high mineralogical stiffness (0.80-0.87); and average porosities of 1.2% for the Horn River and 4.2% for the Exshaw-Patry play. Resource distribution models indicate 50% of Yukon’s marketable gas will be found in 30% of its assessed area, with the best potential for significant volumes located in the very southeast of the territory where play depth and thickness increases.

not_specified

This report presents detailed analytical methodologies and a non-interpretative compilation of outcrop and subsurface data specific to Yukon’s Liard basin. It mainly comprises data collected in the 2012-2016 unconventional study, but also includes legacy data extracted from various sources (principally Geological Survey of Canada publications) on conventional source rock and reservoir potential. The report is organized into two sections: a) a summary of the basin’s geology, exploration history and ultimate resource potential; and b) detailed methods for each of the analytical techniques used to assess unconventional shale potential in the basin. Data, including formation tops and thicknesses, are presented in the suite of appendices.

Ikon Science Canada conducted a preliminary scoping study of shale gas play data from Yukon’s portion of Liard Basin to determine any potential for future assessment of pore pressure variability in the basin to be undertaken or contracted out by YGS at a later date. The study was a desk-top synthesis of existing, publicly-available geological and petrophysical data; no new data were collected as part of this project.

The Eagle Plain basin, having proven hydrocarbon potential, is a relatively underexplored intermontane basin located in northern Yukon . Previous studies of the middle Albian-Cenomanian Parkin Formation and the Turonian Fishing Branch Formation are based on broad lithostratigraphic correlations. The primary goal of the study is to refine the sequence stratigraphic framework of the middle to Upper Cretaceous succession based on sedimentological observations. New findings from this study require subdivision of the stratigraphic nomenclature by defining new informal lithological members. Facies transitions, paleoflow indicators and isopach maps indicate overall westward deepening of the basin. Large-scale, sand-prone mass transport deposits observed in the upper part of the lower Parkin shale member in western Eagle Plain indicate the presence of shelf-to-basin floor relief of at least 100 m. Recognition of significant shelf-to-basin floor topography greatly increases the potential for hydrocarbon reservoirs (gas-dominated) in stratigraphic traps associated with the shelf edge.

An evaluation of hydrocarbon resource potential in Eagle Plain is one aspect of the Yukon Sedimentary Basins Project, a five-year (2008-2013), collaborative Geo-Mapping for Energy and Minerals (GEM) Program of the Geological Survey of Canada (GSC), in partnership with the territorial governments and universities. As part of this project, Yukon Geological Survey (YGS) and Northern Cross (Yukon) Limited (NCY) are collaborating with the GSC to assess shale gas potential of Devonian shale at Eagle Plain. Diamond drill core was retrieved from mineral exploration properties to evaluate shale gas potential of Devonian shale of Road River Group and Canol and Imperial formations. Diamond drill core from four holes, located on the Rich property east of Eagle Plain Hotel, were examined and sampled. The core was systematically sampled and analysed by Rock-Eval pyrolysis, optical microscopy, X-ray diffraction (XRD) mineralogy, and palynology. The results indicate that the succession is thermally overmature with respect to hydrocarbon generation. Due to the high levels of thermal maturity, the Rock-Eval data are unreliable. However, high amounts of residual organic carbon suggest that the Canol Formation has the potential to be an important source rock in the region, under favourable burial conditions. The very high level of thermal maturity of the strata also resulted in very few identifiable Palynomorphs; however, Canol and Imperial formation samples yielded dates of Middle to Late Devonian and Frasnian to Famennian, respectively. XRD analyses indicate Canol Formation shale is highly siliceous whereas Road River Group shale and silty shale of the Imperial Formation are less siliceous and exhibit a more varied lithology. This study suggests that the Canol Formation is more prospective for shale gas than strata of the Imperial Formation or Road River Group.

Initiated by the Northwest Territories Geoscience Office, the project Regional Geoscience Studies and Petroleum Potential, Peel Plateau and Plain, Northwest Territories and Yukon (2005 to 2009) involved partners from the Yukon Geological Survey, Geological Suvey of Canada, as well as universities and industry. The research team coupled field-based studies with subsurface analytical techniques to evaluate the study area's hydrocarbon potential. Over 70 interim publications have been produced. This volume compiles chapters devoted to several stratigraphic petroleum plays, along with structural and petroleum systems elements and a digital geodatabase (or atlas) of spatially based data collected during the course of the project . The result is a comprehensive body of geoscience work for Peel area which will be useful too in oil and gas exploration and for regional land use and business planning endeavours.

Previous studies based on regional geology, sediment type and stratigraphic thickness, concluded that the Bonnet Plume Basin in northeastern Yukon has gas potential, but insignificant oil potential. However, these studies were not based on samples collected from within the basin. For this study, in total, 226 rock samples collected from outcrop and drill core throughout the Bonnet Plume Basin were analyzed by Rock-Eval 6 programmed pyrolysis and combustion to assess the petroleum source-rock potential of the strata. The results indicate that the Road River Formation (Cambrian to Devonian) has no source rock potential, but the Bonnet Plume Formation (Cretaceous to Tertiary) has gas and perhaps oil potential. Potential oil generation in the Bonnet Plume Formation is attributed to the occurrence of liptinite-bearing coal and previously unrecognized, siliceous, oil shale. A hydrocarbon-rich tar associated with a naturally burning coal seam was also discovered in the Bonnet Plume Formation.

Summer 2017 fieldwork in Yukon’s lower Paleozoic shale basins (Selwyn basin and Richardson trough) involved participants from government geological surveys (Yukon Geological Survey, Geological Survey of Canada) and several universities (Queen’s, McGill, St. Francis Xavier, Stanford and Dartmouth College). Research interests include: 1) shale chemostratigraphy and biostratigraphy, and pyrite trace element geochemistry to characterize shale units and assess lower Paleozoic paleoenvironmental conditions and depositional controls; and 2) an assessment of hyper-enriched black shales, specifically the colloquial ‘Nick’ or ‘Ni-Mo’ mineralized Ni-Zn-Mo-PGE deposit, in order to develop internally consistent genetic and exploration models for these types of deposits. This paper describes individual research projects underway and summarizes fieldwork in summer 2017.