Georgina McCartney, May 13 (Reuters) - Sour grades rose on Wednesday, dealers said, as U.S. crude stocks fell and refinery utilization rose, pushing up prices for flagship offshore crude Mars Sour in particular, a grade favored by domestic refiners.

Mars Sour rose $2.25 to a midpoint of a $4.25 premium to U.S. crude futures CLc1.

Crude inventories fell by 4.3 million barrels to 452.9 million barrels in the week ended May 8, the EIA said, compared with analysts' expectations in a Reuters poll for a 2.1-million-barrel draw.

Refinery crude runs USOICR=ECI rose by 370,000 bpd in the week, the EIA said, and utilization rates USOIRU=ECI climbed by 1.6 percentage points in the week to 91.7%. EIA/S

• Light Louisiana Sweet for June delivery fell 20 cents to a midpoint of a 20-cent discount and was seen bid and offered between a discount of 50 cents​​ and 10-cent a barrel premium to U.S. crude futures CLc1

• Mars Sour rose $2.25 to a midpoint of a $4.25 premium and was seen bid and offered between a $4.15 and $4.35 a barrel premium to U.S. crude futures CLc1 ​

• WTI Midland fell 20 cents to a midpoint of a $1.60 premium and was seen bid and offered between a $1.50 and $1.70 a barrel premium to U.S. crude futures CLc1 ​

• West Texas Sour rose 40 cents to a midpoint of a $1.40 discount and was seen bid and offered between a $1.50 and $1.30 a barrel discount to U.S. crude futures CLc1 ​

• WTI at East Houston, also known as MEH, traded between a $2 and $2.20 a barrel premium to U.S. crude futures CLc1 ​

• ICE Brent July futures LCOc1 fell $2.14 to settle at $105.63 a barrel

• WTI June crude CLc1 futures fell $1.16 to settle at $101.02 a barrel

• The Brent/WTI spread narrowed 42 cents to last trade at minus $8.84, after hitting a high of minus $8.45 and a low of minus $9.56