|Title||Organic matter characterization of the Upper Ordovician Utica and Lorraine shales, southern Quebec, Canada|
|Author||Haeri Ardakani, O; Sanei, H; Lavoie, D; Chen, Z; Mechti, N|
|Source||AAPG Search and Discovery Article 90194, 2014 p. 1|
|Alt Series||Earth Sciences Sector, Contribution Series 20130385|
|Publisher||American Association of Petroleum Geologists|
|Meeting||AAPG International Conference & Exhibition; Istanbul; TR; September 14-17, 2014|
|File format||html; pdf|
|NTS||21L; 31H; 31I|
|Area||St. Lawrence Platform|
|Lat/Long WENS|| -75.0000 -71.0000 46.7500 45.0000|
|Subjects||fossil fuels; hydrocarbons; hydrocarbon potential; gas; Utica Shale; natural gas; Paleozoic; Ordovician|
|Illustrations||location maps; stratigraphic columns; photographs; plots|
|Program||Shale Reservoir Characterization, Geoscience for New Energy Supply (GNES)|
|Links||Online - En ligne|
|Abstract||In the eastern Canada, significant industry interest has recently focused on the Upper Ordovician black shales in southern Quebec and Anticosti Island that is the Utica and Lorraine shales and Macasty
Shale, respectively. For the Utica Shale, extensive testing through high pressure hydraulic fracturing has shown that the calcareous shales of the Utica have the capacity to release significant volumes of natural gas.|
The present study reports
the organic matter characterization of core samples of the Upper Ordovician Utica and Lorraine shales in southwestern Quebec. Samples are from deep Utica and near surface samples of both the Utica and Lorraine shales. Sample lithology varying from
shale to fine grained siltstone has present TOC content of ranging from 0.08 to 2.25%. The current TOC content of samples represents only the remaining 92-98% of the residual carbon in the sample. The Tmax values obtained from the Rock-Eval analysis
appear to be unreliable for theses overmature samples due to low S2 values.
The major organic matter constituents are matrix and migrated bitumen and pyrobitumen (for overmature samples of Utica) and chitinozoan skeleton particles. The
reflectance has been measured on matrix and solid bitumen and chitinozoan skeletons. There is a strong agreement between bitumen reflectance and chitinozoan reflectance when they are converted to vitrinite reflectance. The results show that the
samples from the deeper parts of Utica Shale have equivalent VRo of 2.1% and are in the dry gas zone while shallower samples of Utica and Lorraine show equivalent VRo of 1.1% and are in the oil-liquid gas window. This is in agreement with Rock-Eval
data, and the reported well production.
Organic matter comprises of up to 4.7% in volume of total rock. A portion of organic matter in samples may generate porosity, such as matrix pyrobitumen, which is likely resulting from the formation of gas
by secondary cracking of bitumen compounds. Porous matrix solid bitumen appears to be formed during migration and dissemination of bitumen into the porous clay fraction of the rock. This is often associated with significant bacterial sulfate
reduction possible in the early generation and migration of bitumen. Based on organic petrology and Rock-Eval data it seems that the organic-lean siltstone facies of the Utica Shale in this area act as a reservoir and bitumen migrated from
organic-rich intervals within Utica Shale or overlying strata.
|Summary||(Plain Language Summary, not published)|
The present study reports the organic matter characterization of core samples of the Upper Ordovician Utica and Lorraine shales in southwestern Quebec.
Samples are from deep Utica and near surface samples of both the Utica and Lorraine shales.