Canol Formation Oil Shale, Exhumation Charge, and Regional Geology of the Central Mackenzie, NWT 

Thomas Hadlari | Geological Survey of Canada 

April 17, 2018

Doors open 11:30am | Announcements begin at 11:45 am
Marriott Hotel, Kensington Ballroom | 110 9 Avenue SW, Calgary, AB T2G 5A6


Please note: The cut-off for ticket sales is 1:00pm, five business days before the event.April 10, 2018. 
Siliceous “oil shale” of the Canol Formation is the source rock for the Norman Wells oilfield.  Beyond that statement the petroleum geology of the region presents many conundrums: when was oil generated, pre-Cretaceous or Tertiary? When did it migrate? How does the regional structure relate?  Where is the counterpart to the Norman Wells oilfield, and why has exploration drilling of other Devonian reefs been unsuccessful?  What are the implications for unconventional resources?

Over the past 10 years at the GSC many of these questions have been considered as we have undertaken regional geological studies.  A combination of palynology and organic petrology have shown how Cretaceous strata have inherited elevated thermal maturity parameters through recycling of organic matter from Devonian-Mississippian strata.  We now recognize that the thermal maturity of Cretaceous strata is consistent with thermochronological data and so peak thermal conditions for Devonian source rocks were achieved prior to the Cretaceous.  An exhumation model for oil migration through young fractures in the Canol Formation was developed to reconcile the structural setting and relatively old age of oil generation with the nature of the Norman Wells oilfield.  The unique rheology of the Canol Formation is attributed to the lithology being very organic- and chert-rich. 

The exhumation model predicts certain features of the Canol Formation that were tested.  Organic petrology of a Canol Formation surface sample collected adjacent to a fault shows that microfractures are filled with live hydrocarbons.  Mapping of Rock-Eval data shows that there are S1 and S1/TOC positive anomalies that are spatially associated with faults.  This is also shown in cross-plots of S1/TOC vs. distance to known faults.  We interpret that the elevated S1 and S1/TOC measurements are due to migrated hydrocarbons hosted within microfractures of the Canol Formation.  The resulting conclusion is that fractures and microfractures sympathetic to regional faults that were active in latest Tertiary have formed in the Canol formation and have thereby localized oil migration in the vicinity of major faults.  This explains why exploration drilling of undisturbed Devonian reefs draped and sealed by the Canol and Imperial formations has not yielded a counterpart to Normal Wells in the Central Mackenzie, they lack the charge mechanism, and provides an updated picture of the distribution of hydrocarbons in the Canol Formation. 

FIG 1- Durbano, A.M., Hadlari, T., Fallas, K., and Jiang, C., 2017.  Combined depth and S1 maps from Rock-Eval 6/TOC data of the Canol Formation, northern Mackenzie Valley, Northwest Territories; Geological Survey of Canada, Open File 8206.

Thomas Hadlari has a B.Sc. in geology from the University of Saskatchewan (1998) and a Ph.D. from Carleton University (2005).  He works for the Geological Survey of Canada studying a variety of sedimentary basins in northern Canada, from the northern Cordillera to the High Arctic.  The overarching theme of his research is the integration of tectonics and the sedimentary record.