SINGAPORE, Dec 30 (Reuters) - Asia"s cash premiums for 380-cst high-sulphur fuel oil (HSFO) slipped for a third straight session on Thursday, while residual fuel inventories in Singapore dropped to their lowest level in more than 2-1/2 months. The cash differentials for 380-cst HSFO were at a premium of 16 cents per tonne to Singapore quotes, the lowest since Dec. 8. The 380-cst HSFO barge crack for January traded at a discount of $11.91 a barrel to Brent on Thursday, compared with minus $11.75 a barrel on Wednesday. Meanwhile, the front-month VLSFO crack surged to $17.84 per barrel against Dubai crude during Asian trading hours, the highest since February 2020. It was at $16.88 a barrel in the previous session. Cash differential for Asia"s 0.5% VLSFO was at a premium of $16.66 a tonne to Singapore quotes on Thursday, compared with $17.61 per tonne on Wednesday. INVENTORIES - Singapore"s onshore fuel oil stocks dropped 6.5%, or 1.4 million barrels, to 19.6 million barrels, or 2.9 million tonnes, in the week to Dec. 29, according to the Enterprise Singapore data. - Weekly fuel oil inventories have averaged 22.5 million barrels so far this year, having averaged 23.8 million barrels a week last year, Reuters calculations showed. Onshore fuel oil inventories were 10.9% lower compared with year-ago levels. CHINA CRUDE IMPORT QUOTAS - China has issued its first batch of 2022 crude oil import quotas at a volume 11% below 2021"s first allotment, according to industry sources and a document reviewed by Reuters, with large private firms winning out over smaller processors. - Among the 42 companies granted quotas, the country"s top three private refiners -- Zhejiang Petrochemical Corp (ZPC), Hengli Petrochemical and Shenghong Petrochemical -- together won 41.95 million tonnes. That was about 38% of the total and nearly 50% more than a year earlier. WINDOW TRADES - Two VLSFO deals, one 380-cst HSFO trade OTHER NEWS - Oil prices eased on Thursday after the world"s top importer China cut the first batch of crude import allocations for 2022, offsetting the impact of U.S. data showing fuel demand had held up despite soaring Omicron coronavirus infections. - U.S. oil and gas executives are predicting higher production and drilling activity next year as oil prices climb, but say they face sharply higher costs, according to a poll released on Wednesday by the Federal Reserve Bank of Dallas. read more ASSESSMENTS FUEL OIL CASH ($/T) ASIA CLOSE Change % Change Prev Close RIC Cargo - 180cst 445.95 1.65 0.37 444.30 Diff - 180cst -0.85 0.64 -42.95 -1.49 Cargo - 380cst 439.26 0.47 0.11 438.79 Diff - 380cst 0.16 -0.02 -11.11 0.18 Bunker (Ex-wharf)- 380cst 443.00 1.00 0.23 442.00 Bunker (Ex-wharf) Premium 3.74 0.53 16.51 3.21 For a list of derivatives prices, including margins, please double click the RICs below. Brent M1 180cst M1 180cst M1/M2 180cst M2 Visco M1 Visco M2 380cst M1 380cst M1/M2 380cst M2 Cracks 180-Dubai M1 Cracks 180-Dubai M2 East-West M1 East-West M2 Barges M1 Barges M1/M2 Barges M2 Crack Barges-Brent M1 Crack Barges-Brent M2