The 10 Million Barrels Club of Alberta

Before publishing the article The Most Prolific Oil Well in Alberta, I asked many friends in the industry if they could guess the size (in terms of cumulative oil production) of the largest oil well in Alberta. I heard estimates as low as 3 and as high as 10 million barrels. Many were shocked to hear that 100/09-22-051-27W4 has produced 39.7 million barrels. This brought up another interesting question, how many other wells produced 10 million barrels or more?

To date, there are 41 wells that have produced more than 10 million barrels of oil in Alberta. Close to half of the wells on the list are Leduc wells from Central Alberta. In fact, 9 of the top 10 wells are Leduc (D-3) wells. The other formations on the list are: Keg River, Nisku and Swan Hills.

Geologists and reservoir engineers may note that these are all Devonian aged carbonate reefs with active water drives and high pool recoveries (Leduc has a recovery factor of 64% [1]). While these reservoirs are world class, the major operators of the day deserve credit for creating optimized depletion plans and implementing enhanced oil recovery (EOR) schemes, such as miscible floods. These high recoveries are unlikely to have been achieved had proper reservoir management not been a priority.

All 41 wells can be viewed by clicking on this Petro Ninja Maps list and a summary table for the top 15 wells can be found below.

Oil production from the top 10 wells from 1962 onward can be viewed in the interactive chart below. Compare wells by clicking on the well LSD in the legend to show/hide data.

The discovery of Leduc oil in 1947 was the start of the conventional oil boom and you can see in the table above that most of the prolific Canadian oil wells were drilled within the two decades that followed.  The Rainbow Lake discovery well 102/03-10-109-08W6/00 was drilled in 1965 and depending on who you talk to, it could be considered to be the last great conventional oil discovery in Alberta.

That said, with our rich reserves of unconventional oil in the form of oil sands and shale, there’s still a lot to get excited about. While we may never see a vertical well as prolific as 100/09-22-051-27W4 again, there are still conventional opportunities on a smaller scale. Look no further than Whitecap’s Elnora field, which was discovered in 2011.

In less than 4 years, one of the deviated wells in the pool, 102/15-17-035-22W4, has produced more than 800,000 barrels and is still producing at a rate of 1,400 bbl/d. No long horizontal leg required, no multi-stage fracture treatment, just 3 meters of perforations. Surely, this can’t be the only conventional pool that was missed in the 1950s and 1960s!

A valid question might be how many wells drilled in the 70s,80s, and 90s are on track to reach 10 million barrels?  Yes, there will be other conventional wells to join the 10 million barrels club, but not many. Production from oil wells declines exponentially or hyperbolically, with the bulk of their production volume recovered in the early years. 100/09-22-051-27W4 produced 10 million barrels between 1949 and 1965 and it was under production rate control.

After the rate control was lifted, it produced another 10 million barrels in the 3 years between 1965 and 1968! Most of the wells in the 10 million barrels club produced the bulk of their production within the first 20 years. The wells in this club do not owe their membership due to their longer time frame to produce. There are 13 conventional wells that have produced between 9 and 10 million barrels, and only 100/10-29-67-10W5 is still active.

If we neglect its decline rate, and assume it maintains a rate of approximately 70bbl/d, it would be able to join the club in about 10 years. Admittance to the 10 million barrels club is no easy feat.

Article written with assistance from Mike Dupont, P.Eng, a senior petroleum engineer.

Reference:

[1] Lessons from 50 years of production, Ken Potma, Imperial Oil Ltd.