Canadians Eye the Prolific Trenton

Some geologists refer to it as "HTD," or hydrothermal dolomite. Others call it thermobaric or zebra dolomite.

Whatever the descriptor, this rock is characterized by coarsely crystalline, high temperature saddle dolomite, and forms the prolific reservoir trends of the Trenton-Black River that stretch across continental North America.

The Trenton-Black River fairway — containing the world class Albion-Scipio and Lima-Indiana oil fields — crosses into Canada, where it is virtually unexplored to date.

An exploration renaissance, however, is under way in Canada's eastern provinces of Ontario, Quebec and Newfoundland. Fueled by a new understanding of the mechanisms that create hydrothermal dolomites — and the critical role that wrench faults play as conduits for high pressure, high temperature dolomitizing fluids — Canadian oil and gas companies are re-evaluating geological and geophysical data bases for Trenton-Black River potential in eastern Canada's Appalachian front.

Using a tool kit developed to explore for HTD plays in the Devonian and Mississippian strata of western Canada and the Northwest Territories, Canadian E&P firms are tackling Appalachia with new exploration analogs. Canadian firms familiar with the Rocky Mountain front have identified both thin-skinned and thick-skinned tectonics in Appalachia — analogous to leading edge or Triangle Zone geometries observed in the Rockies — that set up large thrust plays involving the Trenton-Black River formations.

The development of pipeline infrastructure in Eastern Canada — and the proximity to large North American markets — has also generated renewed interest in the Ordovician Trenton-Black River play. For a relatively small, up-front exploration investment, Canadian companies ranging in size from "start-ups" to large independents are picking up contiguous blocks of provincial government lands on the scale of hundreds of thousands of acres.

Ontario

The Goldsmith/Lakeshore Field is situated on the shores of Lake Erie in southern Ontario, and Talisman's green pump jacks dot the countryside — in farmyards, beside lakeshore cottages and even inside the loop at the Leamington Race Track. Soil berms fringed with evergreens provide visual relief for residents and cottagers.

Talisman Energy of Calgary has unlocked the key to producing the heterogeneous, hydrothermal reservoirs of the Trenton-Black River. Since acquiring majority interest in the Goldsmith/Lakeshore field in late 1998, Talisman has drilled 100 horizontal wells, extending the field to the northwest and southwest, under the shores of Lake Erie — some of these wells extend 5,000 meters under the lake, and include multi-lateral arms off existing horizontals.

Along the way, Talisman has broken Canadian records for the longest horizontal and multi-lateral horizontal wells.