* February WCS quoted at $40.50/bbl under WTI
* February synthetic quoted at $0.45/bbl under WTI
* Canadian market shrugs off Seaway expansion
CALGARY, Alberta, Jan 11 (Reuters) - Canadian crude prices extended a steep drop on Friday, a day after Enbridge Inc imposed mid-month apportionment on three Canada-United States pipelines, further tightening an already-overbooked transport network, market sources said.
Western Canada Select heavy blend for February delivery last sold for $40.50 a barrel under benchmark West Texas Intermediate, a $1.75 deeper discount than the Thursday settlement, according to Shorcan Energy Brokers. An early deal priced WCS at $41.25 under.
On Thursday, Enbridge set new apportionment on Lines 4, 67 and 6A after a series of operational issues across its system threatened to force large volumes scheduled to move this month to be held over into February.
When pipelines set apportionment, they reduce the actual volumes that shippers can move from amounts nominated. Because less crude can move through the pipeline, backlogs occur. Several lines on the system had already been apportioned for this month.
The 796,000 barrel-per-day Line 4, between Edmonton, Alberta, and Superior, Wisconsin, and 450,000 bpd Line 67, between Hardisty, Alberta, and Superior, are apportioned at 10 percent. Line 6A, which can carry 609,000 bpd between Superior and Griffith, Indiana, is apportioned at 16 percent.
Highlighting the situation, prices sank even as the Seaway pipeline between the Cushing, Oklahoma, hub and U.S. Gulf Coast resumed pumping oil after completing an expansion to 400,000 bpd from 150,000 to help cure a bottleneck.
Traders of Canadian crude pointed out that the new capacity offered no relief as pipelines to get their oil to Cushing were full, and have been for months.
Light synthetic crude for February, meanwhile, also weakened on Friday. It last sold for 45 cents a barrel under WTI, compared with 25 cents under WTI on Thursday.