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Well of the Week – The Once and Future Law

Let us start with a bit of housekeeping, shall we?  While this column is called the Well of the Week, I realize that the publishing interval has not always lived up to that expectation.  I could cite work, vacations or any other of life’s vagaries as reasons. And sometimes you just need a break.

Now, one might expect the series to be renamed but for two reasons.  It already has a good if inaccurate name and I really like alliteration.  So, notwithstanding any publishing date dilation, The Well of the Week it shall remain.  I will endeavour to continue to celebrate the wonders of the Western Canada Sedimentary Basin on a weekly basis.  Now, on with the Well of the Week.

The Canadian Energy Geoscience Association (CEGA) recently wrapped up a very successful edition of it’s flagship technical meeting, the Gussow Conference*.  In recognition of this event, the Petro Ninja – Enlighten Geoscience Well of the Week is the first well into the Wizard Lake D3-A Pool, 100/12-22-048-27W4/00.

What is the connection between this well and the Gussow Conference  Although the 12-22 well had a respectable cumulative production of 570,533.6 m³ of oil and 726,619 e³m³ of gas, Wizard Lake was just one of a number of Leduc pools discovered in the early 1950’sWizard Lake (and Bonnie Glen) were the pools through which William Gussow developed his Principle of Differential Entrapment (which became known as Gussow’s Law).  This groundbreaking theory provided a conceptual framework for understanding the distribution of oil and gas reservoirs.  The gist of how the Principle of Differential Entrapment explained the distribution of oil and gas reservoirs is displayed in Figure 1.  Gussow’s Law also explains the increase in oil density as each trap passes to the next updip trap.


Figure 1. Principle of Differential Entrapment, Gussow (1953).

You might say that is all well and good but is not really applicable to our brave new world of Deep Basin unconventional plays, heavy oil and Steam Assisted Gravity Drainage.  Consider, however, the map of Mannville Oil Density shown in Figure 2.


Figure 2. Mannville Oil Density Contour Map.  Data courtesy of Petro Ninja.

There is a clear updip trend of increasing oil density just as predicted by Gussow’s Law.  There is undoubtedly an overprint of maturation, degradation and other factors, but the predicted distribution holds true.  There have been many changes in our industry in the 7 decades since Gussow published his landmark paper, but the overarching message remains pertinent.

What other ideas from the past are we overlooking in our modern industry?  It might profit us to keep them in mind.

* The conference theme was Geomechanics for Sustainable Energy Development.  Which leads me to wonder; how does one refer to an event where several geomechanicists congregate?  Perhaps a breakout of geomechanicists?


Gussow, W. C, 1953, Differential Trapping of Hydrocarbons. Alberta Society of Petroleum Geologists News Bulletin. Vol. 1, No. 6. (June), Pages 4-5.

Gussow, W. C, 1954, Differential entrapment of oil and gas: a fundamental principle: AAPG Bull., v. 38, p.816-853.

Schowalter, T., 1979. Mechanics of Secondary Hydrocarbon Migration and Entrapment.  The American Association of Petroleum Geologists Bulletin.  V, 63. No, 5 (Mav 1979), P. 723-760.


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