Premiums for Light Louisiana Sweet and Heavy Louisiana Sweet oils strengthened as the spread between West Texas Intermediate and Brent crudes widened for the sixth time in seven trading sessions.

Brent’s premium over WTI, based on April futures contracts, increased 51 cents to $19.51 a barrel, the largest margin since Oct. 24. When Brent gains versus WTI, it strengthens the value of low-sulfur U.S. grades that compete with West African oil priced against the European benchmark.

Light Louisiana Sweet’s (USCSLLSS) premium to WTI added 90 cents to $20.70 a barrel at 4:01 p.m. in New York, according to data compiled by Bloomberg. Heavy Louisiana Sweet (USCSHLSE) increased 80 cents to $22.65 over the U.S. benchmark.

Thunder Horse gained 50 cents to $20.40 a barrel over WTI and Mars Blend (USCSMARS) increased 35 cents to a premium of $15.60. Poseidon’s premium added 65 cents to $15.20, while Southern Green Canyon lost 10 cents to $15.40 over WTI.

West Texas Sour (USCSWTSM)’s discount narrowed 10 cents to $4.50 a barrel.

Western Canada Select (USCSWCAS) was unchanged at $35.75 below WTI. The discount for Bakken oil was unchanged at $18.25 a barrel, and Syncrude was steady at $16 a barrel under WTI.

To contact the reporter on this story: Aaron Clark in New York at aclark27@bloomberg.net

To contact the editor responsible for this story: Dan Stets at dstets@bloomberg.net