Heavy crude steady, synthetic weakens

The discount on Canadian heavy crude versus the West Texas Intermediate (WTI) benchmark was unchanged on Tuesday, while the premium on synthetic crude fell:

* Western Canada Select (WCS) heavy blend crude for September delivery in Hardisty, Alberta, last traded at $19.80 a barrel below WTI, according to NE2 Group, unchanged from the previous day.

* Light synthetic crude from the oil sands for September delivery fell 95 cents to $4.40 a barrel over WTI. Synthetic crude is retreating sharply from record highs hit earlier this summer when maintenance on oil sands upgraders reduced supply.

* Global oil prices settled slightly lower after a see-saw session, in which worries that a slowing economy could cut demand vied with news that some oil exports had been suspended on the Russia-to-Europe Druzhba pipeline that transits Ukraine.