WCS for January delivery in Hardisty, Alberta, settled at $13.20 a barrel below the U.S. benchmark WTI, according to brokerage CalRock, compared with $13.75 on Wednesday.

* After spending much of the year in the $9-$11 range, in large part due to the Trans Mountain pipeline expansion which has given Canadian oil producers additional export capacity, the WCS discount has recently widened.

* The widening can be attributed in part to rising Canadian production growth that has increased pressure along the country’s export pipelines.

* Seasonality is also a factor, with higher levels of diluent required during this time of year to maintain necessary pipeline viscosity out of the oil sands, said Wood Mackenzie analyst Lee Williams.

* Increased competition from similar grades in global markets may also be having an influence following recent increases in OPEC+ volumes, Williams said.

* Global oil prices fell on Thursday as investors focused on Russia-Ukraine peace talks and eyed large surpluses in U.S. gasoline and diesel inventories.

(Reporting by Amanda Stephenson in Calgary; Editing by Krishna Chandra Eluri)