|Title||Canol Formation oil shale, exhumation charge, and regional geology of the Central Mackenzie, NWT|
|Source|| 2019, 2 pages|
|Alt Series||Natural Resources Canada, Contribution Series 20190095|
|Meeting||Canadian Society of Petroleum Geologists, Technical Luncheon; Calgary AB; CA; April 17, 2018|
|Related||This publication is related to Combined depth and S1 maps
from Rock-Eval 6/TOC data of the Canol Formation, northern Mackenzie Valley, Northwest Territories |
|File format||pdf (Adobe® Reader®)|
|Province||Northwest Territories; Yukon|
|NTS||95M; 95N; 95O; 96B; 96C; 96D; 96E; 96F; 96G; 96K; 96L; 96M; 96N; 105P; 106; 116H; 116I; 116P|
|Area||Mackenzie River; Mackenzie Valley; Norman Wells|
|Lat/Long WENS||-137.0000 -122.0000 68.0000 63.0000|
|Subjects||fossil fuels; geochemistry; structural geology; Science and Technology; petroleum resources; hydrocarbon potential; hydrocarbons; oil; bedrock geology; lithology; sedimentary rocks; oil shales; cherts;
structural features; fractures; microfractures; faults; source rocks; hydrocarbon generation; hydrocarbon migration; structural controls; thermal maturation; models; rheology; organic materials; organic geochemistry; Canol Formation; Norman Wells Oil
Field; Phanerozoic; Cenozoic; Tertiary; Mesozoic; Cretaceous; Paleozoic; Carboniferous; Mississippian; Devonian|
|Program||GEM2: Geo-mapping for Energy and Minerals Mackenzie Corridor, Shield to Selwyn|
|Released||2018 04 17|
|Abstract||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
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.
|Summary||(Plain Language Summary, not published)|
This presentation summarizes progress under the GEM2 program on petroleum geology of the Norman Wells oilfield and surrounding areas. A new model was
developed and shown in a prior publication, and this presentation discusses how to apply that model to exploration using existing publicly available data.