Devonian Carbonate Reservoirs, Western Canada, the Gift That Keeps from Giving, a Small E&P Company’S Perspective

Richard A. Walls and Mark Hadley
Fairborne Energy Ltd, Calgary, AB, Canada

Devonian carbonate reservoirs in Alberta have produced 4.5 billion barrels of oil and 31 TCF of natural gas over the past 90 years. Production from these carbonate reservoirs, largely since the late 1940’s, accounts for 30 percent of all the production to date in Western Canada. This talk discusses, from a personal experience level, the role of the small exploration and production company in the exploration and development of these prolific reservoirs.

Until the early 1990’s these Devonian reservoirs were developed mainly by large multinational companies. Over the past 15 to 20 years a decrease in Canadian exploration budgets has resulted in a shift of expertise and exploration activity to the smaller, more entrepreneurial companies. We will discuss this shift and illustrate four specific examples from the authors’ personal experiences.

Two examples are from the Leduc Formation: 1) The Wild River “Pinnacle Reef” trend comprised of small (60 to 200 acres) limestone reservoirs that are deep, sweet (4,500 meters) and overpressured. 2) The Gregg Lake Lower Leduc Reef margin that contains over 100 BCF of natural gas at 5,100 meters.

Overlying the Leduc is the Nisku Formation which is comprised of dolomitized patch reefs, shoals and bank margin buildups. The Wild River Nisku discovery is one of the larger pools discovered in this trend with reserves of 67 BCF of natural gas.

Overlying the Nisku is the Upper Devonian, Wabamun Formation which is a regional, shallow water carbonate ramp deposit. The Berland River gas pool (110 BCF) is an excellent example of fault controlled dolomitization resulting in a high deliverability gas reservoir.

AAPG Search and Discovery Article #90078©2008 AAPG Annual Convention, San Antonio, Texas