The pipeline between Russia and China has 38bcm per year capacity.
The pipelines from the Russia to Western Europe shipped 140bcm per year and 15bcm from LPG tankers.
They are also extracted from different locations within Russia.
It will require a lot more pipeline building for Russia to divert its resources from Europe to China and such projects typically take many years and cost billions. Gas can also be transported via LPG tankers, but the capacity is much lower than a pipeline.
The EU plan is to reduce gas imports from Russia by two-thirds by the end of 2022.
This is an ambitious target and it depends on alternative supplying countries (not least the US) being able to increase their LPG exports and gas by pipeline from Norway.
Russia will have to find other customers for its Oil and Gas and there will be political pressure to discourage buyers and the tankers that would be necessary to transport it.
This will result in a steep decline in revenues to Russia. If they cut supplies off immediately, they cut off the money supply they need to support their economy, which is already under a lot of pressure.
If they cut off the fuel sales suddenly, it would probably lead to a complete economic collapse in Russia. In Europe, there is some gas storage capacity, so the effect would not be immediate.
At the moment it is in the interest of both sides to keep trading. Despite the invasion it is noticeable that none of the pipelines that pass through Ukraine have been hit. The gas still flows to Europe and the money still flows to Russia.
I am sure both sides are carefully weighing up their options. Gas demand for heating will decline in the warmer months in Europe. The difficult time will be next winter. A bit of global warming would help. There are also many ways to reduce demand, not least price hikes. I predict a boom in sales of home insulation.
Russia and Ukraine are also major grain and edible oil exporters and there is another set of dependent countries that will be seriously affected.