|Title||Unconventional reservoir characterization of organic-rich Middle Triassic strata in the Canadian Arctic|
|Author||Kondla, D; Sanei, H; Clackson, C R; Ardakani, O H; Wang, X; Jiang, C|
|Source||vol. 32, (2015), , 2 pages|
|Alt Series||Earth Sciences Sector, Contribution Series 20150146|
|Publisher||The society of organic petrology|
|Meeting||3nd Annual meeting of the society for organic petrology; Yogyakarta; ID; September 20-27 2015|
|Media||paper; on-line; digital|
|Province||Northwest Territories; Nunavut|
|NTS||120B; 120C; 340A; 340B; 340C; 340D; 49C; 49D; 49E; 49F; 49G; 49H; 560; 59C; 59D; 59E; 59F; 59G; 59H; 68G; 68H; 69; 78G; 78H; 79; 88G; 88H; 89; 98G; 98H; 99|
|Lat/Long WENS||-128.0000 -64.0000 84.0000 75.0000|
|Subjects||economic geology; fossil fuels; sedimentology; oil shales; shales; source rocks; reservoir rocks; organic deposits; organic maturity; hydrocarbon maturation; hydrocarbon potential; hydrocarbons, light;
|Program||Shale Reservoir Characterization, Geoscience for New Energy Supply (GNES)|
|Abstract||Organic-rich shale of the Middle Triassic-aged Murray Harbour Formation (Sverdrup Basin, Canadian arctic islands) is examined in this study to determine the potential as a self-sourced hydrocarbon
reservoir. This formation and other Middle Triassic strata in the Sverdrup Basin have already been established as source rocks to many of the conventional hydrocarbon fields discovered there (Brooks et al., 1992). |
Samples from a core taken
from the basin centre (Fig. 1) were used to characterize organic matter and porosity as well as to define the hydrocarbon potential and thermal maturity of the unit at this location. The interval is within the oil generation window and contains
abundant free light oil and solid bitumen dispersed within the clay-rich matrix of the rock. The median total organic carbon and S2 values for the interval are 3.2 wt.% and 6.3 mg HC/g Rock, indicating good organic-richness and hydrocarbon generation
potential. Total porosity ranges from 1.7 % to 10.9 % and shows a strong negative correlation with solid bitumen concentration. This suggests that solid bitumen is occupying pore space rather than contributing to the total porosity of the interval at
this level of thermal maturity. Other studies (e.g. Chalmers and Bustin, 2008) have revealed that micropore surface area, within all types of kerogen, increases with thermal maturity. If this relationship maintains for solid bitumen in the Murray
Harbour Formation, then areas of higher thermal maturity within the unit may contain more abundant sites for gas adsorption. Significant portions of the Middle Triassic strata are located in the deeper, east-central part of the Sverdrup Basin, where
regionally, rocks are thermally overmature. This area may be a more prospective zone for shale gas exploration.
Macro- and microscale phosphatic nodules are visible throughout the cored interval. Using reflected light microscopy, these nodules
appear saturated with bitumen, and when exposed to ultraviolet light, rapidly exude free light hydrocarbons. Field emission scanning electron microscopy reveals that these nodules contain abundant macroporosity (>50 nm diameter), which is at least
partially occupied by light oil and labile fractions of solid bitumen. A positive relationship between total porosity and both elemental phosphorus concentration and apatite (Ca5(PO4)3(OH,F,Cl)) concentration exists within the interval, suggesting
that the porosity provided by the nodules is significant. These findings can be applied to analogous fine-grained successions to potentially identify hydrocarbon-rich zones for development.
Brooks, P.W., Embry, A.F., Goodarzi,
F., Stewart, R., 1992. Organic geochemistry and biological marker geochemistry of Schei Point Group (Triassic) and recovered oils from the Sverdrup Basin (Arctic Islands, Canada). Bulletin of Canadian Petroleum Geology 40, 173-187.
G.R.L., Bustin, R.M., 2008. Lower Cretaceous gas shales in northeastern British Columbia, Part I: geological controls on methane sorption capacity. Bulletin of Canadian Petroleum Geology 56, 1-21.
Embry, A.F., Beauchamp, B., 2008. Sverdrup Basin.
in Hsu, K.J., ed. Sedimentary Basins of the World Vol 5. The Sedimentary Basins of the United States and Canada. Andrew D. Miall, Elsevier, The Netherlands, 451-471.
|Summary||(Plain Language Summary, not published)|
This study examines the hydrocarbon generation and storage potential of the Middle Triassic Murray Harbour Formation in the Canadian arctic. Solid
bitumen occupies porosity while phosphatic nodules contribute to porosity within the unit. These findings can be applied to analogous, established unconventional hydrocarbon reservoirs to improve exploration and production.