SINGAPORE/HOUSTON, Jan 22 (Reuters) - Prices of Canadian

and U.S. West Texas Intermediate crude oil to Asia jumped after

shipping costs rallied on concerns that wider U.S. sanctions on

the Russian fleet are tightening ship availability, trade

sources said on Tuesday.

Asian refiners face a margin squeeze as their costs of crude

and shipping have spiked since Washington earlier this month

imposed sweeping new sanctions targeting Russian insurers,

tankers and oil producers.

Discounts for Canadian crude exported via the Trans Mountain

pipeline (TMX) and delivered to China in April have narrowed

$1-$2 a barrel from the previous month, the sources said.

China's Rongsheng Petrochemical, top buyer of Canadian TMX

crude, bought Access Western Blend (AWB) crude cargoes from

TotalEnergies unit Totsa and CNOOC at $2-$3 a barrel

below June ICE Brent for April delivery, they said, versus deals

at about $4 a barrel discount for March.

The Chinese refiner also bought a Cold Lake cargo from

Macquarie at a discount of about $1.70 a barrel to June ICE

Brent for April delivery, the sources said.

Another Chinese refiner, Shenghong Petrochemical, also

bought a Cold Lake cargo from BP at similar levels, they

added.

Similarly, offers for U.S. West Texas Intermediate (WTI)

Midland crude have jumped close to $6 a barrel to dated Brent

for deliveries to North Asia, the sources said, although trade

has slowed as the current trading cycle is coming to an end.

The cost of chartering a Very Large Crude Carrier (VLCC)

capable of carrying 2 million barrels of oil from the U.S. Gulf

Coast to China exceeded $10 million on Monday, data from a

shipbroker showed, a jump of nearly $4 million since Jan. 10

when the U.S. imposed additional sanctions on Russian producers

and more than 100 tankers.

U.S. major Exxon Mobil ( XOM ) tentatively chartered a

VLCC from the U.S. Gulf Coast to China for February for $10.1

million on Friday, ship broker data showed.

Japan's Mitsui & Co ( MITSF ) chartered a VLCC from North Sea to

South Korea for $9.95 million for late January, according to

shipbrokers, about $3.6 million above previous such deals.

June Goh, a senior analyst at market intelligence firm

Sparta Commodities, expects Asian refiners to secure supply by

snapping up cargoes from West Africa, Brazil and Canada,

although they have become more costly due to higher freight

costs and rising premiums.

This could erode refiners' margins and lead to more

refinery run cuts, she added.

Strong buying from China and India also pushed spot premiums

for Middle East crude to their highest in more than two years

last week.