The Canadian heavy oil differential widened slightly against the West Texas Intermediate (WTI) benchmark on Wednesday, while the light oil differential tripped its widest level in 6-1/2 years.
* Western Canada Select (WCS) heavy blend crude for November delivery in Hardisty, Alberta, settled at $42.25 a barrel below the WTI benchmark crude futures , compared with Tuesday's settle of $42, according to Shorcan Energy brokers. * Light synthetic crude from the oil sands for November delivery settled at $20.75 under WTI, the widest level since 2012, compared with Tuesday's settle of $19.50 under. * Widening differentials reflect stored oil "bursting at the seams," and scarce pipeline capacity – "there's just nowhere for oil to go," said Samir Kayande, director at RS Energy Group. * Canadian crude oil exports by rail reached a record 206,624 bpd in July, up just 1 percent from June's pace, according to the National Energy Board. * Rail shipments likely increased significantly in the months since then, and a recent Cenovus Energy Inc deal with railways will add to a faster pace beginning in the fourth quarter, analysts at AltaCorp Capital Research said. * Brent crude rose nearly 2 percent after hitting a four-year high on Wednesday as the market focused on U.S. sanctions on Iran taking effect in November while shrugging off the year's largest weekly build in U.S. crude stockpiles and reports of higher Saudi Arabian and Russian production. (Reporting by Rod Nickel in Winnipeg, Manitoba; editing by Grant McCool)