* November synthetic quoted at $4.25/bbl over WTI
* WCS quoted at $14.65/bbl under WTI
* Shell, Suncor conducting maintenance on units
CALGARY, Alberta, Oct 11 (Reuters) - Canadian cash crudeprices weakened on Thursday with some refineries and processingunits in Canada and the United States going off line formaintenance.
Light synthetic crude for November deliver last sold for$4.25 a barrel over benchmark West Texas Intermediate, comparedwith $6 a barrel over WTI on Wednesday, according to ShorcanEnergy Brokers.
November Western Canada Select heavy blend was quoted at$14.65 a barrel under WTI, a 40-cent deeper discount than onWednesday.
Prices have weakened dramatically since the start of themonth, when the differentials prompted some shippers to movesupplies away from the Cushing, Oklahoma, storage hub as theycould not compete with the local prices when transport wasfactored in.
Royal Dutch Shell Plc
said late Wednesday it wastaking an unspecified unit at its Scotford oil sands upgraderdown for maintenance.
The 255,000 barrel a day upgrader, located near Edmonton,Alberta, processes bitumen from Shell's Athabasca Oil SandsProject.
Suncor Energy Inc
, meanwhile, is scheduled to startplanned maintenance at its 93,000 bpd Commerce City, Colorado,refinery this weekend. One of the crude units is slated to bedown,
(Reporting by Jeffrey Jones)
Keywords: MARKET CANCRUDE