[airborne]

Here in PA we ave Centralia.

Those coal veins have been burning for decades.

And just like Centralia, that “Gates of Hell” won’t be able to be put out.

[cpdiii]

“And just like Centralia, that “Gates of Hell” won’t be able to be put out.”

It can be put out but Centralia can not.

1. Drill down to the producing formation, it may take several drillings to different locations in the formation.
2. Pump heavy drilling fluid into the formation which will then start bringing it up into the old well bore and eventually the hydrostatic pressure will be greater than the formation pressure and it will stop.
3. Pump cement into the old bore hole.

A lot of cement and drilling fluid and expenses will be involved. Thus what we really have is a cost benefit question. Is the cost of the lost gas greater than the cost of killing the old well? It might be cheaper to just let it burn.

[JohnBovenmyer]

Centralized is the best known, in the US, of thousands of coal seam fires. At least we known when it started. The believed oldest such, "Burning Mountain" down under in NSW, is estimated to be 6000 years old.