Saudi crude is mainly sold under long-term contracts, but these usually contain clauses that allow for variations in volumes delivered, either at Aramco's behest or the request of the clients.
This dynamic can be seen in China this year, with the world's biggest crude importer dropping imports from Saudi in November, but boosting those from Russia and Angola.
China imported 1.72 million barrels per day (bpd) from Saudi Arabia in November, down from 1.87 million bpd in October, according to data compiled by Refinitiv Oil Research.
However, China's imports from Russia rose to 1.90 million bpd in November from October's 1.82 million bpd, while those from Angola jumped to 680,000 bpd from 480,000 bpd the prior month.
Russian crude will have to be offered at a discount, possible to the point where the $60 a barrel price cap becomes irrelevant.