(Removes reference to synthetic price arbitrage being open insecond paragraph)
By Nia Williams
CALGARY, Alberta, April 1 (Reuters) - Canadian syntheticcrude prices strengthened on Wednesday, the first day of tradingMay barrels, as maintenance on oil sands upgraders in northernAlberta cut supply to the market.
Expectations that Enbridge Inc's Line 9 pipelinewill begin service in the second quarter also helped demand forsynthetic.
The newly-reversed Line 9 will carry 300,000 barrels per dayof mainly sweet and synthetic crude from Sarnia, Ontario, toMontreal, Quebec.
Light synthetic crude from the oil sands for May deliverylast traded at $2.75 per barrel above the West TexasIntermediate benchmark, according to Shorcan Energy brokers.
That compares with a settlement on Tuesday of $2.25 perbarrel above the benchmark.
Upgrader turnarounds at Royal Dutch Shell and thejoint-venture Syncrude oil sands project are taking place in thesecond quarter, while Suncor Energy Inc also hasmaintenance scheduled at its facilities.
Upgraders convert mined bitumen into refinery-readysynthetic crude.
Western Canada Select heavy blend for May delivery lasttraded at $12.55 per barrel below the benchmark, little changedfrom the previous day when it changed hands at $12.50 per barrelbelow WTI. (Editing by Grant McCool)