Canada crude-Grades strengthen despite refinery work

* November synthetic quoted at $12.25/bbl over WTI

* WCS quoted at $9.80.bbl under WTI

* Illinois, Montana refineries down for work

CALGARY, Alberta, Oct 2 (Reuters) - Canadian crude prices strengthened on Tuesday, despite outages at some key U.S. refineries, after Syncrude Canada Ltd, one of the top to oil sands mining operations, reported lower production.

Synthetic crude for November delivery was last quoted at $12.25 a barrel under benchmark West Texas Intermediate, compared with $10.50 a barrel under on Monday, according to Shorcan Energy Brokers.

November Western Canada Select heavy blend sold for $9.80 a barrel under WTI, compared with $10.65 a barrel under a day earlier.

Some market sources expressed surprise at the resilient price strength, which has already prompted shippers to move supplies away from the Cushing, Oklahoma, storage hub.

Enbridge Inc said last week that it had no need to ration space on its Spearhead pipeline to Cushing from Illinois next month as nominations fell. It was the first month with no apportionment on that line since January.

The 362,000 barrel Wood River, Illinois, refinery run by Phillips 66 and Cenovus Energy Inc began planned maintenance last week.

On Tuesday, local media reported Exxon Mobil Corp's 60,000 bpd Billings, Montana, plant began planned work to replace part of a fluid catalytic cracking unit.

However, Canadian Oil Sands Ltd reported this week that production at Syncrude, in which it has the largest ownership interest, fell to 318,900 bpd in September, from 359,900 bpd in August, as excessive rainfall hampered bitumen output.

(Reporting by Jeffrey Jones; Editing by Bob Burgdorfer)

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