The Saudis want to build a pipeline across Syria to tap into the lucrative European market, where prices are $10-$12/mcf.
The Russians do NOT want that built as it breaks their monopoly. In exchange for a naval base in the Med, Putin is supporting Assad to ensure the pipeline doesn't get built. This means that the winter Olympics will almost certainly be hit by Chechen terrorists, as they are controlled by the Saudis.