Enterprise Singapore data showed a significant drop in import and export activity for both gasoil and jet for the week ended January 16.

"LSMGO demand has risen significantly this year, especially for ships running the Taiwan-China route," a CPC official said.

"I think the market is slightly tighter without the Coastal and Brightoil barges," a bunker trader in Singapore said.

"The economic case for LNG as the marine fuel of choice for newbuilds is growing stronger each month," Keller said.

Its crude exports have fallen recently as rough weather shut in loadings at its key oil terminals.

After posting near 50 million mt in annual sales for two consecutive years, Singapore is hoping to push its bunker fuel sales even further in 2019.

The impact of the sanctions may also have unintended impacts as Venezuela redirects barrels to Asian markets in need of heavy crudes, leaving US Gulf Coast refiners to scramble for barrels from Colombia, Mexico, Iraq and other sources to fill a roughly 500,000 b/d gap.