Core analyses of the Macasty formation on Anticosti Island in the Gulf of St. Lawrence offshore Quebec indicate that the shales are favorable for the production of petroleum, said Petrolia, Rimouski, Que.
The company said the new data will aid in advancing the next stage of exploration and in determining drillsites. Petrolia and its partner hold rights to more than 1.5 million acres or more than 76% of the island’s land area.
The results relate to cores taken in 2012 from three stratigraphic coreholes on the western part of the island and to analyses of samples from 14 older wells spread across the entire island. The results are higher than those used by Sproule Associates Ltd. in its resource assessment report dated July 12, 2011, for the best estimate of total petroleum initially in place of 33.9 billion bbl of oil equivalent.
A thermal maturity study indicates that the licenses lie predominantly in the oil window. That study, conducted by Rudolf Bertrand, visiting scholar at Quebec’s National Institute of Scientific Research, consisted of thermal maturity characterization of 200 samples taken every 100 m from surface to the top of the Trenton formation.
Geochemical (Rock Eval), petrophysical, and mineralogical analyses were performed by Weatherford and TerraTek Labs. Nine hundred samples were analyzed using Rock Eval. In the three coreholes drilled in 2012, the samples from Macasty were taken with a very high sampling distribution, i.e., every 50 cm.
The results reveal impressive average values for total organic carbon of nearly 4% over the whole thickness of the Macasty formation, which is 91.5 m for Princeton Lake, 57 m for Highcliff, and 29 m for Oil River.
The Rock Eval analysis conducted on the older wells also yielded high TOC values for mainly the whole area under license. These TOC results are higher than those wells in Ohio, which is recognized for its petroleum production from the Utica formation, lateral equivalent of the Macasty.
The hydrocarbon concentrations present in the rock (S1) indicate a favorable potential for hydrocarbon production, i.e., averaging 4.48 mg/g at Princeton Lake, 3.20 mg/g at Highcliff, and 2.21 mg/g at Oil River. Porosities and permeabilities are also favorable for production.
Mineralogical analyses by TerraTek and Weatherford show that the Macasty is made up of a large assemblage of nonclay minerals dominated by quartz and, in lesser proportions, by carbonates, feldspars, and pyrite. The small proportion of clay minerals favors rock fracturing and constitutes a positive criterion in terms of the production potential of the Macasty using fracture stimulation techniques, Petrolia concluded.