Heavy crude differential narrows slightly

The Canadian heavy oil differential narrowed against the West Texas Intermediate (WTI) benchmark on Tuesday:

* Western Canada Select (WCS) heavy blend crude for September delivery in Hardisty, Alberta, settled at $31.00 a barrel below the WTI benchmark crude futures , according to Shorcan Energy brokers. That compared with Friday's settle of $31.15 under WTI.

* The differential has grown as U.S. refiners plan more extensive than usual downtime for maintenance this autumn, and pipelines are clogged, industry officials said.

* Analysts said they expect the differential to remain higher than usual, and volatile, in coming months.

* The Syncrude oil sands site began restoring production last month, adding to a squeeze moving crude from Alberta via pipeline and rail.

* Light synthetic crude from the oil sands for September delivery last traded at $3 a barrel over WTI, unchanged from Friday's settle.

(Reporting by Julie Gordon in Vancouver; Editing by Richard Chang)