SINGAPORE, Nov 18 (Reuters) - Spot premiums for Russian ESPO crude, a staple grade for top importer China, slumped by about $2 a barrel after hitting their highest in nearly two years earlier this week, trade sources said on Thursday.

Russian producer Surgutneftegaz sold three January-loading at premiums of between $4 and $4.30 a barrel to Dubai quotes, they said, the lowest in two months. (Reporting by Florence Tan; Editing by Himani Sarkar)