The WCSB supply letterUpdated September 23, 2026 · Source AER ST3/ST39/ST53 via the WCSB S&D model; company guidance via the forward maintenance calendar (compiled 2026-09-22)
The WCSB supply/demand balance, storage, and removals. The page Oilsands Magazine does not have.
Executive call
Tradable supply averages 4,239.2 kb/d from Nov 2026 onward, +139.1 kb/d versus the Oct 2026 context month (4,100.1 kb/d).
Oct 2026 is the heaviest modeled maintenance month at 164.4 kb/d offline: Horizon 35-day turnaround; Syncrude Coker 8-2 turnaround; Syncrude Coker 8-2 mine dial-back; Imperial Cold Lake 3Q/4Q 2026 turnaround; Christina Lake F/G turnaround tail (assumed, not company-stated). No confirmed maintenance sits in the model math from Jan 2027 onward.
Largest projected month-to-month supply moves: Oct 2026 to Nov 2026: +360.8 kb/d; Dec 2026 to Jan 2027: -347.9 kb/d; May 2027 to Jun 2027: +270.9 kb/d.
Implied storage change ranges from a high of -305.6 kb/d in Apr 2027 to a low of -512.2 kb/d in Feb 2027 (positive = build into commercial storage, negative = draw).
All figures kb/d, computed from the table below. A bullet is omitted when its value is null; nothing here is estimated beyond the model.
Forward balance (kb/d)
Oct 2026 is the context month (post-nominations); the tradable window runs Nov 2026 onward.
Line
Oct 2026
Nov 2026
Dec 2026
Jan 2027
Feb 2027
Mar 2027
Apr 2027
May 2027
Jun 2027
Jul 2027
Aug 2027
Sep 2027
12-mo avg
Total WCSB crude supply
4,100.1
4,460.9
4,517.2
4,169.3
4,200.1
4,293.2
4,065.7
3,860.9
4,131.8
4,362.6
4,336.1
4,233.8
4,227.6
In-situ bitumen
1,996.7
2,044.6
2,064.2
2,011.1
2,017.6
2,027.5
1,960.2
1,973.6
2,000.4
2,038.0
2,017.9
1,954.9
2,008.9
Mined bitumen + SCO
1,427.5
1,725.9
1,768.0
1,521.4
1,532.4
1,602.9
1,439.3
1,245.2
1,491.6
1,671.9
1,652.5
1,621.1
1,558.3
Conventional crude
675.9
690.4
685.0
636.8
650.1
662.8
666.2
642.1
639.8
652.7
665.7
657.8
660.4
SCO / synthetic crude
1,291.2
1,487.0
1,493.6
1,366.2
1,391.9
1,399.4
1,251.7
1,073.8
1,249.6
1,441.6
1,440.6
1,278.4
1,347.1
Marketable bitumen (dilbit)
2,133.0
2,283.5
2,338.6
2,166.3
2,158.1
2,231.0
2,147.8
2,145.0
2,242.4
2,268.3
2,229.8
2,297.6
2,220.1
Bitumen sent for further processing
1,492.3
1,725.1
1,723.2
1,582.0
1,602.1
1,619.7
1,469.2
1,258.5
1,455.4
1,654.9
1,665.8
1,483.2
1,561.0
Diluent imports
309.4
310.4
327.1
342.5
333.9
326.4
350.9
338.5
329.4
317.9
287.1
285.5
321.6
Total Alberta use
581.1
620.8
625.3
590.9
612.1
605.6
539.3
526.4
578.5
619.2
610.3
558.2
589.0
Removals from Alberta
4,439.1
4,624.6
4,700.3
4,357.2
4,434.1
4,391.3
4,182.9
4,116.5
4,372.4
4,431.6
4,467.2
4,384.0
4,408.4
Maintenance offline
164.4
23.0
3.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
15.9
Implied storage change
-610.7
-474.1
-481.3
-436.3
-512.2
-377.3
-305.6
-443.5
-489.7
-370.3
-454.3
-422.9
-448.2
All flows in kb/d. Blank cells are months AER has not published yet, not zeros.
Supply stack
Vintage: AER ST3/ST53 actuals through 2026-07 (ST39 through 2026-05), pulled 2026-09-22; Aug-Sep 2026 nowcast estimated, built 2026-09-23; forecast built 2026-09-22. Stack: in-situ bitumen, mined bitumen + SCO, conventional crude; ties exactly to Total WCSB crude supply every month. Orange shading marks months with modeled maintenance offline.
Vintage: AER ST3/ST53 actuals through 2026-07 (ST39 through 2026-05), pulled 2026-09-22; Aug-Sep 2026 nowcast estimated, built 2026-09-23; forecast built 2026-09-22. Implied storage change = supply total minus maintenance offline plus diluent imports minus refinery demand minus removals (kb/d). Positive = builds into commercial storage; negative = draws.
Vintage: AER ST3/ST53 actuals through 2026-07 (ST39 through 2026-05), pulled 2026-09-22; Aug-Sep 2026 nowcast estimated, built 2026-09-23; forecast built 2026-09-22. Maintenance calendar compiled 2026-09-22; modeled at the leaves 2026-09-23. Maintenance offline memo: modeled kb/d offline by month. Pattern-indicated turnarounds carry no volume and never enter the math.
Forecast built 2026-09-22; Aug-Sep 2026 nowcast built 2026-09-23
2026-09-23
Every number on this page traces to a row above. Anything missing its own source line is flagged in place; nothing ships with an unsourced number.
Heavy Reading · the WCSB supply letter.
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