--> Organic Matter Characterization of the Upper Ordovician Utica and Lorraine Shales, Southern Quebec, Canada
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Previous HitOrganicNext Hit Previous HitMatterNext Hit Previous HitCharacterizationNext Hit of the Previous HitUpperNext Hit Previous HitOrdovicianNext Hit Previous HitUticaNext Hit and Previous HitLorraineNext Hit Shales, Southern Quebec, Canada

Abstract

In the eastern Canada, significant industry interest has recently focused on the Previous HitUpperNext Hit Previous HitOrdovicianNext Hit black shales in southern Quebec and Anticosti Island that is the Previous HitUticaNext Hit and Previous HitLorraineNext Hit shales and Macasty Shale, respectively. For the Previous HitUticaNext Hit Shale, extensive testing through high pressure hydraulic fracturing has shown that the calcareous shales of the Previous HitUticaNext Hit have the capacity to release significant volumes of natural gas. The present study reports the Previous HitorganicNext Hit Previous HitmatterNext Hit Previous HitcharacterizationNext Hit of core samples of the Previous HitUpperNext Hit Previous HitOrdovicianNext Hit Previous HitUticaNext Hit and Previous HitLorraineNext Hit shales in southwestern Quebec. Samples are from deep Previous HitUticaNext Hit and near surface samples of both the Previous HitUticaNext Hit and Previous HitLorraineNext Hit 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 Previous HitorganicNext Hit Previous HitmatterNext Hit constituents are matrix and migrated bitumen and pyrobitumen (for overmature samples of Previous HitUticaNext Hit) 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 Previous HitUticaNext Hit Shale have equivalent VRo of 2.1% and are in the dry gas zone while shallower samples of Previous HitUticaNext Hit and Previous HitLorraineNext Hit 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. Previous HitOrganicNext Hit Previous HitmatterNext Hit comprises of up to 4.7% in volume of total rock. A portion of Previous HitorganicNext Hit Previous HitmatterNext Hit 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 Previous HitorganicNext Hit petrology and Rock-Eval data it seems that the Previous HitorganicNext Hit-lean siltstone facies of the Previous HitUticaNext Hit Shale in this area act as a reservoir and bitumen migrated from Previous HitorganicNext Hit-rich intervals within Previous HitUticaTop Shale or overlying strata.