* August WCS quoted at $17.25/bbl under WTI
* Light synthetic flat with WTI
* Imperial restarts Strathcona after 9-wk turnaround
CALGARY, Alberta, July 16 (Reuters) - Canadian cash crude oil prices extended recent gains on Monday as demand picked up with the restart of Imperial Oil Ltd's Alberta refinery after more than two months of planned maintenance.
Western Canada Select heavy blend for August delivery last sold for $17.25 a barrel under benchmark West Texas Intermediate, compared with $19 under WTI on Friday, according to Shorcan Energy Brokers. That was its smallest discount in more than seven weeks.
Light synthetic for August was quoted on par with WTI, compared with $1.15 under late last week. That was its tightest differential since May 24.
Canadian crude spreads have tightened steadily since the start of the month. Momentum increased last week when Enbridge Inc rescheduled a three-day maintenance shutdown of its 491,000 barrel a day Line 5 oil pipeline in the U.S. Midwest for later this month, rather than pushing it into August.
On Monday, Imperial Oil said its 187,000 bpd Strathcona refinery near Edmonton, Alberta, resumed normal operations after nine weeks of planned upkeep. There had been some speculation in the market that the work might be extended.
Work continues, however, on units at Imperial's 121,000 bpd Sarnia, Ontario, plant, where repairs to a damaged coker unit began in early May. Some equipment at the plant is still operation, the company has said.