A new shale play is delighting Michigan explorers, and it's being developed by a Canadian firm. Encana Corp., based in Calgary, recently unveiled a Collingwood and Utica shale play in the heart of the venerable Michigan Basin.

The company revealed that it had accumulated 250,000 net acres of leases. Its first well, drilled by subsidiary Petoskey Exploration LLC, in Missaukee County, produced at an average rate of 2.5 million cubic feet equivalent per day during its first 30 days on production. The well, drilled close to the depocenter of the basin, produced primarily from the Collingwood and had some contribution from the Utica.

A report by Ross Smith Energy Group notes the Middle Ordovician Collingwood is sandwiched between the Trenton Black River limestone (below) and the Utica shale (above) in the northern third of Michigan. Potentially, the play could stretch across an attractive swath of Michigan's Lower Peninsula; Encana's leasehold spans seven counties.

In southern Ontario the Collingwood has been recognized as an oil shale reservoir since Colonel Drake drilled his Titusville well. According to a 1983 paper by J.F. Barker et al, shale oil was produced in Ontario from a plant near Collingwood on Lake Huron, where the shale outcrops. From 1859 to 1863, oil was retorted from the shale to produce fuel and lubricants. Ironically, it was the discovery of conventional oil in Ontario that rendered the retorting business uneconomic.

Barker and his colleagues reported that the Collingwood often included intervals of two to five meters with more than 3% TOC, and posited it had major economic potential for oil shale. Now it appears that Encana holds that same opinion of the shale, at least where it is gas- and condensate-prone in the depths of the Michigan Basin.