Wrong. Russia keeps a fleet in a port in Syria and has substantial trade and commerce with them historically. It is not about oil.
Fact: 50% of Russia’s annual budget comes from oil revenue.
Fact: The Saudis have been pumping to keep the price of oil down because they know what it is doing to the Persians and the Russians.
There are reports of 700 Russian tanks and 100,000 Russian troops in Syria, along with 170 bombers. All of this protected by SAMs. ISIS doesn’t have an Air Force.
That is enough firepower and troops to form two Army Corps, and an entire Bomber Group.
They aren’t going after ISIS.