Planned shutdowns, the Horizon September 2026 example, and why the calendar beats the snapshot.
Field guide entry · written September 23, 2026.
A turnaround is a planned full or partial shutdown for inspection, maintenance, and equipment replacement. Upgraders and mines both take them, typically on multi-year cycles, usually lasting weeks. Unlike an unplanned outage, the timing and rough size are known in advance: companies put them in budget guidance and talk about them on earnings calls. The operator plans and executes the work; at Horizon that is CNRL.
The worked example. CNRL's 2026 budget called a 35-day Horizon turnaround starting in September, with a 29 kb/d impact on the annual average: 29 times 365 is 10,585 thousand barrels of lost production for the year. September actuals absorbed 6,900 of that (a 230 kb/d bridge for the month). The remainder, 10,585 minus 6,900, divided by 31 October days, is 119 kb/d: the October residual in the model. That is how a single turnaround gets split across two months without double counting.
Injection-month barrels trade during the prior calendar month, before nominations. By the time a barrel is being injected, its trading window is already closed. So the current outage snapshot is history; what prices the next tradable barrel is the forward maintenance calendar by project. That is why this site keeps a 12-month forward calendar and splits it three ways: public-confirmed (the company stated the number and the timing), guidance-sourced (verified from guidance or transcripts), and pattern-indicated (the seasonal study flags the window, but it carries no volume and never enters the math). Unplanned outages are a different animal: they hit the current month with no warning, and the job is to read them in the actuals and reset the forward calendar. That is why the maintenance section carries both: the forward calendar for what is scheduled, and the event log for what actually happened.
The market does not trade today's outages. It trades the next year of scheduled downtime, project by project. If your maintenance view stops at what is offline right now, you are pricing the wrong month.
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