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Well of the Week – Wells that make you go “Hmmm” no. VII

There are several intriguing aspects of the Jean Marie member of the Devonian Redknife formation. I will quickly discuss a few of them before the big reveal of today’s Well of the Week.

First of all, maybe I am an old softie but I think the name Jean Marie is much more attractive than plain old “Upper Nisku equivalent.” The real appeal, however, is due to many technical facets of this play. Stratigraphy, sedimentology, structure, diagenesis and petroleum geology all come to bear.

The Jean Marie illustrates the importance of basin filling patterns in providing the accommodation space for the member to expand from a 15 to 20 metre thick prograding shelf carbonate to downslope reef mounds of over one hundred metres thick (Switzer et al., 1994).

Figure 1. Cross-section Y – Y’ illustrating Jean Marie thickness changes towards the shelf edge. Switzer et al. (1994).

Zooming in to the shelf edge itself, the Jean Marie provides an excellent lesson on the sedimentology of a carbonate shoal (Wendte et al. (2009).

Figure 2. Jean Marie schematic cross-section. Wendte et al. (2009).

The previous WotW broached the subject of the importance of understanding structural features east of the Cordilleran trend. Structural fabrics are every bit as important in developing the Jean Marie play in that normal faults are the primary mechanism for transporting the fluids necessary for reservoir enhancement through hydrothermal dolomitization.

Figure 3. Jean Marie hydrothermal dolomitization model. Wendte et al. (2009).

The penultimate factoid is that the Jean Marie is a singular play, given that it is a dry gas dominated Lower Pressure Deep Basin hosted in a carbonate (LeTourneau, 1999). And the Jean Marie is, generally speaking, a dry gas play with over 99% of its production being gas on a boe basis.

Figure 4. Cumulative Production Pie Chart.

But it is the exception to this production characteristic that qualifies 200/a-080-K/094-P-07/00 as a Petro NinjaEnlighten Geoscience Well of the Week. Of the 2,699 wells categorized as Jean Marie producers, only 12 have reported oil production. But the a-080-K well, with a cumulative oil production of 86,469.3 m3, has produced over 76.5% of all of the oil in the Jean Marie.

Figure 5. Embedded Production plot for 200/a-080-K/094-P-07/00. Data courtesy of Petro Ninja Maps.

If that doesn’t make you go “Hmmm”, what will?


Letourneau; J.P. (1991)Petroleum hydrogeology of the Jean Marie Member, northeastern British Columbia. Bulletin of Canadian Petroleum Geology; 39 (2): 217. doi:

Switzer, S. B., Holland, W. G., Christie, D. S., Graf, G. C., Hedinger, A. S., McAuley, R. J., Wierzbicki, R. A. and Packard, J. J. (1994): Devonian Woodbend-Winterburn Strata of the Western Canada Sedimentary Basin; in Geological Atlas of the Western Canada Sedimentary Basin, G.D. Mossop and I. Shetsen (comp.), Canadian Society of Petroleum Geologists and Alberta Research Council, URL, [04/26/2020].

Wendte, J., Byrnes, A. and Sargent; D. (2009) The control of hydrothermal dolomitization and associated fracturing on porosity and permeability of reservoir facies of the Upper Devonian Jean Marie Member (Redknife Formation) in the July Lake area of northeastern British Columbia. Bulletin of Canadian Petroleum Geology; 57 (4): 387–408. doi:

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