From what I understand, the gas is not flowing out of a pipe at ground level; the leak is deep underground and it is diffusing into rock and coming up over a wide area. It's not clear that combustion could be sustained in that configuration. I have as much oil/gas industry experience as rube goldberg, but I suppose if they put a huge upside-down funnel over the area maybe they could collect it and light the top, but I have no idea whether the radius of that funnel would have to be 10m or 10km.

I feel a good solution would be to implement a carbon tax, and an unburnt methane tax at the greenhouse equivalent, and start charging the company the estimated leak. I imagine their engineers would become more motivated.

That's how the Door to Hell[1] was made.

1: https://en.wikipedia.org/wiki/Door_to_Hell