It is up to the government to set the rules and allow the market to play within them. Expropriation of oilfields would imply the government pick winners and losers and would be a devastating blow to property rights. If you advocate change, you should focus on advocating (fair) change in the regulatory framework.
Why not simply let the market decide which carbon emissions are of the most marginal value to society. You do this through cap and trade or carbon taxes, not from picking winners and losers.