The light oil that makes bitumen move, and the 30 percent of every dilbit barrel you are really buying.
Field guide entry · written September 23, 2026.
Diluent is light hydrocarbon liquid, mostly natural-gas condensate and natural gasoline (pentanes plus), blended into bitumen so it meets pipeline density and viscosity specs. The standard spec at Edmonton is known as CRW condensate. Producers also use butane and even synthetic crude as blendstock depending on price and availability.
Raw bitumen is around 8 API: at room temperature it barely flows. A pipeline needs something in the low-20s API with capped viscosity. The industry-standard answer is dilbit: roughly 70 percent bitumen and 30 percent diluent. The ratio moves a bit with the season and the exact spec, but 30 percent is the number the whole system is built around. For every three barrels of bitumen moved, close to one barrel of diluent has to be sourced, shipped north, blended, shipped south, and then mostly recovered at the refinery.
Edmonton is the trading and delivery hub. Supply comes from Alberta NGL fractionation (Montney and Duvernay condensate), from US imports, and from refinery recovery. Canada has never produced enough condensate domestically to cover oil sands demand, so imports from the US are a structural feature of the trade, not a temporary fix. Dedicated return loops move diluent back north: the Corridor system runs diluted bitumen south and diluent north on the same corridor, and plants like Sturgeon recover about 28 of the 29 kb/d they take in.
Nobody owns diluent as a system. Producers buy it, midstream companies move it, and Edmonton is where it trades. Enbridge sets the quality specs every shipper must meet. The clearest dedicated asset is the Corridor system, which runs diluent back north to the Albian mines on a reverse loop.
Thirty percent of every "bitumen" pipeline barrel is not bitumen. Diluent is a cost on every dilbit barrel, a logistics system of its own, and a second market that can squeeze independently: when condensate runs tight, the heavy barrel feels it.
?public=1.