Interesting. Oil companies frack to get petroleum, and are OK with burning the natural gas at the well head. I get the impression that a big reason they choose to capture the natural gas instead is criticism of just burning it by environmentalists, but maybe it is more environmentally friendly to just burn it in the absence of the political will to ban fracking. (I am assuming that burning at the well head is an effective way to reduce the amount of unburnt gas released.)