U.S. cash crude grades largely strengthened on Friday, with differentials drawing some support from concerns that tension in the Middle East could affect supply moving through the Red Sea.

Attacks from Houthi-controlled Yemen struck two Liberian-flagged ships in the Bab al-Mandab Strait on Friday, a U.S. defence official said, underlining the threat to vessels in shipping lanes being targeted by the Iran-aligned group. Disrupted flows via the Suez canal could lend support if crude tankers are prevented access on a supply bottleneck.

Coastal grades firmed on Friday. Light Louisiana Sweet gained 20 cents at a midpoint of a $3.00 premium, while Mars Sour gained 10 cents at a midpoint of a 5-cent discount.

WTI’s discount to international benchmark Brent widened during the session on Friday, last trading at $4.78 a barrel at 15:46 CST.

A wider discount attracts foreign buyers of U.S. grades, helping to edge prices up as players spot the arbitrage opportunity.

In refining news, a small crude distillation unit (CDU) at TotalEnergies’ 238,000 barrel-per-day (bpd) Port Arthur, Texas, refinery, remains shut three weeks after the end of planned overhaul work, said people familiar with plant operations on Friday.

Money managers cut their net long U.S. crude futures and options positions by 17,074 contracts to 30,623 in the week to Dec. 12, the U.S. Commodity Futures Trading Commission (CFTC) said on Friday.

Light Louisiana Sweet for January delivery gained 20 cents at a midpoint of a $3.00 premium and was seen bid and offered between a $2.90 and $3.10 a barrel premium to U.S. crude futures CLc1 ​

Mars Sour gained 10 cents at a midpoint of a 5-cent discount and was seen bid and offered between a discount of 30 cents​​ and 20-cent a barrel premium to U.S. crude futures CLc1 ​

WTI Midland gained 5 cents at a midpoint of a $1.35 premium and was seen bid and offered between a $1.25 and $1.45 a barrel premium to U.S. crude futures CLc1 ​

West Texas Sour was unchanged at a midpoint of a 80-cent premium and was seen bid and offered between a 60-cent and $1.00 a barrel premium to U.S. crude futures CLc1 ​

WTI at East Houston, also known as MEH, traded between a $1.65 and $1.85 a barrel premium to U.S. crude futures CLc1 ​

ICE Brent February futures fell 6 cents to settle at $76.55 a barrel on Friday​.

WTI January crude futures fell 15 cents to settle at $71.43 a barrel on Friday​.

The Brent/WTI spread widened last to minus $4.78, after hitting a high of minus $4.63 and a low of minus $4.86.
Source: Reuters (Reporting by Georgina McCartney in Houston, Editing by Rosalba O’Brien)