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Unconventional Oil Play Assessment in Northeastern British Columbia, Canada


Horizontal drilling and multi-frac completions have greatly augmented British Columbia gas and liquids resources by providing economic access to unconventional (low-permeability) reservoirs. However, relatively little new unconventional oil production has been brought on stream in this gas-prone area of the Western Canada Sedimentary Basin. We identified exploration and exploitation fairways for oil in unconventional reservoirs throughout the stratigraphic column, with the exception of the Montney Formation, as it is already an active oil and liquids drilling target. Regional geological assessment of reservoir and production trends identified potential in conventional, tight, and shale reservoirs. We reviewed existing files of analytical data submitted to the Regulator - standard core analysis, geochemistry / maturity, mineralogy, geomechanical properties - and tabulated them to support future detailed analyses. Where analytical data were lacking on promising plays, we sampled cores and completed comprehensive laboratory analyses to fill the gaps. Finally, we analyzed test and production data from a reservoir engineering perspective to better understand the scope and quality of potential resource oil fairways. Of 19 reservoir intervals deemed suitable for analysis, 10 demonstrated little prospectivity for reasons including: lack of extensive low-permeability reservoir facies, poor geomechanical properties (low “frackability”), and lack of viable oil charge. Six demonstrated some resource oil potential based on existing oil shows and favourable geological / geomechanical characteristics, but lacked either substantial horizontal / multi-frac testing, or evidence of substantive resource oil fairways. Only two reservoirs showed potential to be top-priority unconventional oil targets. Cretaceous Chinkeh Formation sandstones are prospective for tight oil across a broad, poorly-defined fairway downdip from the existing Maxhamish gas field. The Triassic Halfway Formation presents halo oil potential in limited-permeability shoreface sandstones offsetting conventional production, which has been focused on higher-quality tidal channel sandstones. New Halfway production could be brought on stream quickly using existing infrastructure, but developing the Chinkeh would require new processing and pipeline construction in a relatively remote part of the province.