US Cash Crude-Grades firm to multi-year highs as WTI/Brent spread widens on Iran crisis

HOUSTON, March 19 (Reuters) - U.S. coastal cash crude oil grades eased marginally on Thursday after touching multi-year highs in recent sessions, dealers said, even as the discount for U.S. crude futures versus Brent widened to its most in 13 years.

The premium of WTI at East Houston, also known as MEH, to U.S. West Texas Intermediate crude eased from a six-year high to $4.25 touched, while premiums for Mars eased to $6 a barrel.

U.S. West Texas Intermediate crude traded at as much as a $20.69 a barrel discount to Brent during the session on Wednesday, its largest since March 2013. Typically, a spread wider than $4 encourages exports.

Brent crude was up on Thursday but well off session highs of $119 a barrel while U.S. crude futures finished with a small loss hours after hitting a session high over $100 a barrel.

Oil loadings by Saudi Arabia at the Red Sea port of Yanbu were disrupted briefly on Thursday, two sources told Reuters, after a drone fell on the nearby Aramco-Exxon refinery, SAMREF.

The port is the only export outlet for the world's largest oil exporter after Iran effectively blocked tanker traffic leaving the Gulf via the Strait of Hormuz.

Kuwait Petroleum Corp's Mina al-Ahmadi and Mina Abdullah refineries were also targeted by drones on Thursday, resulting in fires at both sites, the state news agency said.

U.S. President Donald Trump said on Thursday he had told Israel not to repeat its attacks on Iranian natural gas infrastructure as tit-for-tat strikes on energy plants sent energy prices spiralling, sharply escalating the U.S.-Israeli war on Iran.

In refining news, Chevron's CVX.N 285,000-barrel-per-day El Segundo refinery in southern California has brought a jet fuel-producing unit back online after five months of repairs and maintenance following a fire, the company said on Thursday.

• Light Louisiana Sweet for April delivery eased to a midpoint of a $5.60 premium and was seen bid and offered between a $5.00 and $6.20 a barrel premium to U.S. crude futures CLc1

• Mars Sour eased to a midpoint of a $6 premium and was seen bid and offered between a $5.75 and $6.25 a barrel premium to U.S. crude futures CLc1

• WTI Midland firmed to a midpoint of a $2.85 premium and was seen bid and offered between a $2.60 and $3.10 a barrel premium to U.S. crude futures CLc1

• West Texas Sour eased to a midpoint of a 15-cent discount and was seen bid and offered between a​ discount of 30 cents and parity to U.S. crude futures CLc1

• WTI at East Houston , also known as MEH, traded between a $4.00 and $4.50 a barrel premium to U.S. crude futures CLc1

• ICE Brent May futures LCOc1 rose $1.27 to settle at $108.65 a barrel on Thursday​.

• WTI April crude CLc1 futures fell 18 cents to settle at $96.14 a barrel on Thursday​.

• The Brent/WTI spread widened $1.21 to to last trade at minus $13.13, after hitting a high of minus $9.99 and a low of minus $20.69.