US Cash Crude-Offshore grades ease after spiking in previous session

HOUSTON, Dec 18 (Reuters) - U.S. Gulf of Mexico grades largely weakened on Thursday after briefly spiking in the previous session.

Mars eased 80 cents, while SGC weakened $1.30. The grades had firmed on Wednesday on worries that escalating tensions between the U.S. and Venezuela could impact Chevron's shipments of crude from the Latam country to the United states.

Chevron's shipments have so far not been impacted and vessel have been departing with crude.

Venezuela also authorized two very large crude carriers (VLCC) to set sail for China, according to two sources familiar with Venezuela's oil export operations, which would be only the second and third supertankers to depart the country since the U.S. seized a ship carrying Venezuelan oil last week.

In the futures market, oil prices settled marginally higher on Thursday as investors assessed the likelihood of further U.S. sanctions against Russia and the supply risks posed by a blockade of Venezuelan oil tankers.

• Light Louisiana Sweet for January delivery was flat at a midpoint of a $2.60 premium and was seen bid and offered between a $2.40 and $2.80 a barrel premium to U.S. crude futures CLc1

• Mars Sour eased 80 cents to a midpoint of a 80-cent discount and was seen bid and offered between a $1.00 and 60-cent a barrel discount to U.S. crude futures CLc1

• WTI Midland firmed 5 cents to a midpoint of a 40-cent premium and was seen bid and offered between a 20-cent and 60-cent a barrel premium to U.S. crude futures CLc1 ​

• West Texas Sour eased 35 cents to a midpoint of a $2.1 discount and was seen bid and offered between a $2.30 and $1.90 a barrel discount to U.S. crude futures CLc1 ​

• WTI at East Houston , also known as MEH, traded between a 40-cent and 90-cent a barrel premium to U.S. crude futures CLc1

• ICE Brent February futures LCOc1 rose 14 cents to settle at $59.82 a barrel on Thursday​

• WTI January crude CLc1 futures rose 21 cents to settle at $56.15 a barrel on Thursday​.

• The Brent/WTI spread narrowed 2 cents to to last trade at minus $3.85, after hitting a high of minus $3.78 and a low of minus $3.87.

(Reporting by Arathy Somasekhar in Houston; Editing by Rashmi Aich)

((Arathy.s@tr.com))