Pioneering Development Efforts of the Ordovician-aged Utica/Macasty Shale Plays: Quebec Sedimentary Basins, Eastern Canada
Marcil, Jean-Sebastien; Lavoie, Jean-Yves1; Dorrins, Peter K.; Lavoie, Jeremie; and Mechti, Nabila
Since 2005, 30 new wells were drilled in southern Quebec. The Ordovician calcareous shales of the Utica Group, rich in organic matter are the main target of recent exploration efforts. The calcareous and organic-rich Utica Shales belongs to the Early Paleozoic time Saint Lawrence Lowlands geological province. At its maximal vertical extent, the shales is 300 meters of graptolitic, brownish, organic rich and laminated calcareous mudstone. Similar to the Eagleford shale, the calcitic mineralogy of the Utica make the shale competent, hard and brittle. Highest TOC reach 6% and indicate a Type II organic matter origin. Current knowledge have led operators subdivide the shale gas potential in different play types. In general, the gas encountered is a low (wet) to high maturity (dry) gas. To date, most operations were performed in in the deep thermogenic shale gas play (1000-2000 meters). With OGIP estimates ranging from 120 to 160 Bcf per section, the play is considered promising.
Located in the Gulf of St. Lawrence in Quebec, Anticosti Island extends over an area of 7,943 sq-km (3,103 sq-mi). The current exploration phase recognized the potential of the Middle Ordovician Macasty Shale as a liquid-rich resource play (potential for light oil/condensate production). Macasty has good to excellent organic richness (Type II). At its deepest point of the island the shale attained its full thermal maturity for Oil Generation (Late Oil Window based on Rock-Eval/Tmax data). The Macasty porosity compares favorably with other North American shale resource plays and which may be a positive indicator for potential resources initially-in-place. Technical evaluation indicates that the level of thermal maturity observed thus far for the shale in the Deep Macasty Fairway compares favorably with published findings for the oil-rich Utica/Point Pleasant Shale in Ohio and the Eagle Ford Shale in Texas.
The exploration of Ordovician shales in Quebec is a combination of science, intuition, perseverance and adaptability. But the premises of the story remain similar to those found in other sedimentary basins: the presence of brittle shale which acted as a major source rock. The people living in Quebec are energy intensive and more than half of this energy comes from oil and natural gas. The development of oil and gas potential of Québec will generate significant economic benefits for citizens and will have positive impacts on the competitiveness of its sources of supply.
AAPG Search and Discovery Article #90166©2013 AAPG International Conference & Exhibition, Cartagena, Colombia, 8-11 September 2013