There were literally hundreds of article about $20 oil in some places in the world for low quality or difficult to ship oil, but today the price of the high quality Saudi oil too plunged to $23.8 for shipment to Europe. Middle East state owned companies sell their oil in long-term contracts which are dependent on spot prices. Saudi Aramco oil for shipment to Europe in February is priced at discount of $4.85 to Brent. At current Brent oil price at $28.65, this discount leads to $23.80 selling price. Brent needs to fall another 4-5 dollars so that we can see sub $20 Saudi oil. At the same time Mexico oil is priced at around $12 ($12 discount to Dubai price which is at the moment hovers around $24).
Let's see how low can oil go so that state owned companies will sell their oil for free. Don't laugh, free oil is possible, some Dakota oil is already priced at negative prices, www.bloomberg.com/news/articles/2016-01-.... Who thought that severel years ago there might be negative interest rates.
I guess $25-$30 oil is the point where every oil producer is screaming for the help and thus oil low is not far away, maybe $2-3 from today's.