Yes.
1. Russia is the number 2 exporter of oil, behind Saudi Arabia: https://en.wikipedia.org/wiki/List_of_countries_by_oil_expor...
2. The fact that the US only gets 3% of its oil from Russia is kind of irrelevant - it's largely a global market.
3. The idea that Russia can just switch to selling all of its oil to China, so then the West can then get its oil from someplace else (a) is not feasible and (b) would completely defeat the purpose of sanctions in any case.
4. Prices are always set at the margins. A relatively small shortfall can cause a huge price increase primarily because, when there is a shortfall, the price needs to increase enough for some buyers to just drop out of the market altogether.