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Unconventional petroleum systems analysis of upper Devonian organic-rich shales in the Horn River and Liard Basins, and adjacent Western Canadian Sedimentary Basin

University of British Columbia

Vast resources of unconventional gas and, potentially natural gas liquids occur in shales in north-eastern British Columbia (NEBC) in Devonian mudrocks. The reservoir properties and present-day petroleum systems of these Devonian mudrocks in NEBC (Liard Basin, Horn River Basin and Cordova Embayment) and Western Alberta have been investigated in this research. In the study area, perspective gas and oil shale reservoirs include the Horn River and Muskwa formations and equivalent horizons within the Besa River Formation of the Liard Basin. The Muskwa and Horn River formations are largely over mature with respect to the oil window within NEBC with maturity decreasing from west to east. Quartz (mainly biogenic in origin) is the dominant mineral, particularly within the Muskwa Formation where quartz content has an average of 71 wt%. The Horn River Formation contains more carbonate and clay minerals than the Muskwa Formation with an average quartz content of only 43 wt%. TOC content ranges from <1 % to 12%, with an average of 2.9%. TOC is highest within the Muskwa Formation and Evie Member of the Horn River Formation. Quartz and TOC exhibit similar trends on a regional scale with the highest quartz and TOC found within the central and northern portions of the Horn River Basin. Porosity values range from 1 to 9% with an average of 5% in the Muskwa Formation and 3.5% in the Horn River Formation. One dimensional basin models constructed at 24 well locations across the study area demonstrate the impact of different geological events on the depth of burial and present day thermal maturity of the basin. In all of the models, peak burial (and peak maturity) occurred during foreland subsidence. The timing of hydrocarbon generation varies greatly across the study area due to varying amounts of subsidence during the Paleozoic, differing heat flow regimes, and the depth of maximum burial during foreland subsidence with the onset of generation ranging from the Carboniferous in the Liard Basin to the Late Cretaceous in Western Alberta. The results of the basin models can help identify potential areas of condensate production within NEBC.

Text

2019-11-04

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/72183

Geological Sciences

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/