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 letter. The tradable call first; history is context.
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.
Next tradable injection month
2026-11
next tradable injection month
+191.4 kb/d
forward balance into storage
2026-10-01
trading window opens
164.4 kb/d
October maintenance offline (context)
Vintage: cycle as of 2026-09-22. Injection-month M barrels trade during calendar month M-1, before noms day (Enbridge Mainline).
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.
November injection barrels start trading October 1, eight days out. The forward balance for November is +191 kb/d into storage; October was the heavy maintenance month at 164 kb/d offline.
Basis signal is bearish: October preliminary -16.48 vs September final -15.32, a 1.16 widening. November basis is unobservable (no strips supplied); nothing fabricated.
The April-2027 tank-top scare is withdrawn. The rebuilt balance has storage roughly flat from 58.7 Mbbl toward ~45.1 Mbbl by Sep 2027; utilization is not computable on the stale provisional capacity.
The encyclopedia
Project profiles: every producing oil-sands project in the model, grouped by method and operator, with live production charts, maintenance calendars, and market-relevance lines.
Reports public
Agency-grade deep reads, one consistent template. Phone-readable,
prints cleanly to PDF. Every chart and table carries a source line; every edition
carries a full source appendix.
Energy-Aspects-style balance sheet: ST3 lines with 12 months of
actuals, a 2-month nowcast, and 12 months of model forecast. Drill from any aggregate into
ST53 project leaves and ST39 facility rows; tap any row for its source,
vintage, method, and the reasoning behind the numbers. Maintenance offline
drills into per-event turnaround rows.
Full-page table with CSV export.
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.
Green columns from Nov 2026 are the tradable window.
Desk monitors licensed data
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Six flags mixed: 4 public, 2 licensed
Live regime reads as of 2026-09-22. Signals: BULLISH-BASIS = tighter WCS differential ahead; BEARISH-BASIS = wider differential ahead; WATCH/NEUTRAL as labeled. Regime reads, not forecasts.
1. Enbridge Mainline apportionment
WATCH
Enbridge curtailing 12.4% of nominations. Moderate stress, not pipe-full.
Flips: Flips bearish-basis if Enbridge apportionment sustains above 25% or Keystone apportionment snaps back above 30%. Flips neutral if Enbridge apportionment falls below 5% with utilization under 90%.
Vintage: CER data through Jun 2026, pulled 2026-09-22 (approx 3-month lag)
3. Oil sands forward maintenance
NEUTRAL
Oct 2026 carries the only material confirmed offline barrels: Horizon residual 119 kb/d (Oct 1-12), Syncrude Coker 8-2 to ~Oct 9, Cold Lake Q4 portion. Q4 2026: Suncor Base Plant -20 kb/d confirmed. 5 pattern-indicated (ASSUMED) windows in 2027, no volumes.
Flips: Flips if an unplanned upgrader outage hits (Suncor/Syncrude trips are the historical shock) or a 2027 turnaround gets company-confirmed with volume.
Flips: Flips bearish-basis if runs fall 300+ kb/d under norm (deep turnaround season or unplanned refinery outage). Flips bullish-basis on a strong post-turnaround ramp back above norm.
Vintage: EIA v2 weekly, week ending 2026-09-11 (pulled 2026-09-22); norm = same-week mean over available history
5. Crude-by-rail volumes and rail arb
NEUTRAL
Rail loadings 87,977 bbl/d (May 2026), far below the December 2018 peak of 364,893 bbl/d. Relief valve idle; pipe egress covering the barrel.
Flips: Flips bearish-basis if loadings climb past ~150-200k bbl/d (rail arb opening means diffs wide enough to pay for rail). Flips neutral as loadings fall back under ~100k bbl/d.
Vintage: CER crude-by-rail file, last updated 22 Jul 2026; latest observation May 2026 (file carries December annual snapshots plus latest month)
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Heavy Reading · the WCSB supply letter.
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