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Well of the Week – Does the Halfway have ROUS?

Faithful readers of the Petro NinjaEnlighten Geoscience Well of the Week will recall that the Doig manifests hydrocarbon accumulations where shoreface complexes subcrop against the Charlie Lake, and that these shorefaces can be recognized hundreds of kilometres along strike.

The Halfway does the Doig one better by throwing at least one more unconformity and some structuring into the mix. Caplan and Moslow (1997) document that the Halfway in Peejay and similar fields is a north – south trending tidal inlet facies deposited obliquely to the Doig subcrop pool underneath.

East – west stratigraphic cross section in Peejay field. Caplan and Moslow (1997)

The histogram of Cumulative Oil Production in the Peejay and Milligan fields indicates that, even when the influence of a water-flood is considered, there are at least two major populations. One over 750,000 barrels and another under 350,000 barrels.

Histogram of Cumulative Oil Production for “Halfway” wells in the Peejay and Milligan fields. Histogram created with data courtesy of Petro Ninja.

Posting cumulative production pie charts of the wells producing over 750,000 barrels on the Halfway tidal inlet isopach map from Caplan and Moslow (1997) leads to the conclusion that the Halfway is home to ROUS (Reserves of Unusual Size) and reinforces the importance of identifying the best producing facies.

Halfway tidal inlet isopach and wells over 750,000 bbls cumulative oil production. After Caplan and Moslow (1997)

Hat-tip to the Vieux Skier for the conversation which led to the Princess Bride allusion.


Caplan, M. L. Caplan and T. F. Moslow; Tectonic controls on preservation of Middle Triassic Halfway reservoir facies, Peejay Field, northeastern British Columbia: a new hydrocarbon exploration model. Bulletin of Canadian Petroleum Geology 1997; 45 (4): 595–613. doi:


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