Russia has an economy about like Venezuela. Without selling oil your average Russian on the street will be turning to cannibalism just like how they used to do in the good old Soviet days they're still yearning for.
Most of Western Europe bar the UK get their gas and oil from Russia. They are moving away from this, but not quickly enough.
And the Central and Eastern states, thanks to the legacy of communism are heavily tied to Russian oil and gas -- conservative Poles berate the Tusk government for not drilling shale gas in Poland
and the Baltics are utterly and completely dependent on Russian oil and gas. Also, they have had silly petty squabbles and not set up railway lines or oil lines to link their capitals to Warsaw and Berlin (railway lines from Riga, Talinn and Vilnius lead to Moscow, a legacy of Soviet times).
This can change, but right now, Moscow doesn't need to invade to threaten them.
Also, they don't serve a strategic or propaganda purpose like Ukraine (the "birthplace of Russia" -- which is a lie, more like one of the two birthplaces of Moscowy -- the other being the land of Genghis Khan)
GPH, also, if the Russians do not sell oil, they have other things and exports to poorer countries. They would become heavily impoverished, but they are not that bad as cannibalism.