China uses secret network to pay Iran for oil - WSJ

A supply vessel approaches the Nasr production platform, located 32 kilometers southwest of Siri Island in the Persian Gulf, where crude from the Alvand field is mixed with oil from the Sivan, Dena, and Nosrat fields before being piped to Siri Island for processing and storage.
A supply vessel approaches the Nasr production platform, located 32 kilometers southwest of Siri Island in the Persian Gulf, where crude from the Alvand field is mixed with oil from the Sivan, Dena, and Nosrat fields before being piped to Siri Island for processing and storage.

China is secretly funneling billions of dollars to Iran through a covert payment system that bypasses US sanctions by swapping oil for infrastructure projects, The Wall Street Journal reported, saying the hidden conduit enabled Tehran to receive up to $8.4 billion last year.