Junex Inc., Quebec City, Que., said processed 2D seismic data clearly indicate drillable structural and stratigraphic elements associated with the Macasty shale and deeper conventional reservoir targets on the company’s acreage on Anticosti Island in the Gulf of St. Lawrence offshore Quebec.
Junex plans to select the top five drilling locations in coming weeks from the 224 line-km of 2D seismic that it shot in mid-2012 on its 233,275-acre block of exploratory permits on the island (OGJ Online, July 16, 2012). Junex said its interpretation of the data is well advanced and that it has identified a number of prospective structures.
The operator noted that consulting engineers have previously issued a best estimate of undiscovered shale oil initially in place in the Macasty on its acreage at 12.2 billion bbl.
Each prospect’s primary objectives include conventional reservoirs in geological formations underlying the Macasty, including the Trenton-Black River and Romaine (Ellenburger-equivalent) carbonate sequences. The secondary objective is the overlying Macasty, whose oil potential the company intends to further evaluate via a combination of coring, specialized core analysis, and other analytical methods during and after future drilling.
Drilling permits will be sought in preparation for the drilling of five conventional vertical wells as early as the next drilling season in mid-2013.
Geologically, Junex said, its acreage on Anticosti is principally situated to the south of and on the deeper side of the major Jupiter Fault Zone. With respect to the Macasty, it is the stratigraphic equivalent of the Utica shale in the St. Lawrence Lowlands and the oil-rich Utica/Point Pleasant shale in Ohio.
Junex’s acreage is dominantly situated in the Deep Macasty Fairway, where, based on available information, the company’s mapping indicates that the Macasty averages 80 m thick or twice the thickness encountered in earlier wells drilled by others north of the Jupiter fault outside the Deep Fairway.
Junex’s interpretation of pertinent geochemical lab data indicates that the organic-rich Macasty on its Deep Fairway acreage places it well within the oil window, which compares much more favorably with published findings for the oil-rich Utica/Point Pleasant shale in Ohio and the Eagle Ford shale in Texas than currently does the less thermally mature Macasty outside the Deep Fairway.
Based on its direct experience with the Utica shale in the St. Lawrence Lowlands at varying formation depths and more specifically with the oil it recovered from the Utica shale in the Junex St-Augustin-1 well in 2009, Junex considers that the greater formation depth of the Macasty on its acreage in the Deep Fairway should translate into greater formation pressure or reservoir energy that could yield a greater oil production potential than the Macasty in shallower areas outside the Deep Fairway.
Furthermore, based on the consulting engineers’ best estimate, the Macasty on Junex’s acreage has an average potential original oil in place of 33.5 million bbl/sq mile, which appears to be much superior to that calculated for areas of the island controlled by other operators.
With respect to the deeper conventional reservoirs including the Trenton-Black River and Romaine, other operators drilled many wells the past 15 years that targeted these formations in areas north of the Jupiter fault. Available well data and published results show that those wells were not commercially successful. Where porous reservoir rock was encountered, formation water was dominantly present and only minor hydrocarbon shows were observed.
In Junex’s opinion, the Jupiter fault could have acted as a sealing barrier to the migration of oil from mature source rocks on the south side of the fault into these geological sequences on the north side. On the basis of this geological concept and its recently-acquired seismic data Junex intends to drill the five new conventional vertical wells on its acreage south of the fault, targeting mainly the Trenton-Black River and Romaine formations.
