* May synthetic crude sells for $2.50 under WTI
* WCS for May quoted at $23 under WTI
CALGARY, Alberta, April 5 (Reuters) - Canadian synthetic crude discounts were unchanged on Thursday as supplies remain constrained by upgrader outages.
Synthetic crude last traded from $2.50 per barrel under the West Texas Intermediate benchmark, unchanged from earlier this week. However the discount is much tighter than levels last month when April synthetic was selling for $10 per barrel under WTI.
Syncrude Canada has yet to restart a 110,000 barrel per day coker unit at its oil sands operations after shutting it down for 30-days of repair work following a March 9 fire.
It remains unclear when Syncrude might take another coker, known as 8-3, down for work. That turnaround was postponed due to the unplanned repairs on the other unit.
Suncor Energy Inc has also reduced its synthetic crude production after it closed a fractionator unit for repairs on March 14. The work has reduced synthetic output by 60 percent, to about 140,000 barrels per day. Repairs will take as much as five weeks.
Heavy crude spreads narrowed. Western Canada Select heavy crude last traded for $23.00 per barrel under the West Texas Intermediate benchmark as demand rises headed into the summer driving season and asphalt production increases.
Overall Canadian crude spreads have widened this year as production has surged and export pipeline capacity has been tight.