For examples of already-existing companies being nationalised, see RBS in the UK, or Cardiff Airport in wales. After the 9/11 attacks in the US, all airport security firms were forcibly nationalised.
If you are claiming that the definition of socialist requires it to be done with guns instead of money, I don't know what to say. However be aware that if somebody did create an oil company in norway against the law then I imagine that some nice people from the government would have to come and ask them not to. If they refused despite that - they may actually have to make use of the state monopoly of violence.