Canada crude-Husky upgrader fire lifts synthetic spreads

* March synthetic quoted at $4.60-$4.90/bbl over WTI

* Upgrader to run at reduced rates for indefinite period

* WCS quoted at $26 to $27 under WTI

CALGARY, Alberta, Feb 7 (Reuters) - The premium on Canadian synthetic crude widened on Monday on word that Husky Energy Inc's (HSE.TO) heavy oil upgrader was running at cut rates after a small fire at the facility, market sources said.

The situation was also said to be a factor behind a bigger discount on heavy grades, such as Western Canada Select.

Synthetic light oil for March delivery was discussed at about $4.60 a barrel above benchmark West Texas Intermediate, then rose to at least $4.90 a bbl above WTI after word of the upgrader situation spread.

That compares to about $4 a bbl over WTI a week ago.

Reduced output at the 82,000 barrel a day Lloydminster upgrader exacerbated an already-tight market due to the Jan. 6 fire at Canadian Natural Resources Ltd's (CNQ.TO) Horizon oil sands project, which remains shut for an indefinite period.

Husky declined to give current production rates or an estimate of how long repairs will take. [ID:nN07257590]

March WCS was quoted in a range of $26 to $27 a bbl under WT, a wider spread than last week.

The outage at the Husky plant that turns heavy crude into light synthetic oil could leave more heavy barrels in a Western Canadian market that is glutted due to restrictions on Enbridge Inc's (ENB.TO) export pipeline system.

Enbridge said on Monday it began a planned five-day maintenance outage on its 290,000 bpd Line 6B to Sarnia, Ontario, from Griffith, Indiana.

It is the first of two outages on the line, which ruptured in Michigan last year, spilling 20,000 barrels of oil and causing a nine-week shutdown. The second outage is due to start around March 7. (Reporting by Jeffrey Jones; editing by Rob Wilson)