Showing formations originally drilled through.

    Next Slide

Lets start by showing the relevant underground rock layers/formations through which a gas well is drilled in an abbreviated, drawing view.  There is the green good ground water formation that needs protected, the brown bad groundwater formation that needs to be kept to itself, the black coal seam that needs protected from gas, and the blue gas-bearing target rock formation/strata from which the driller wants to produce gas.  (The driller may want to produce oil or a combination, but most wells these days are for methane gas so this slide show will stick to that.  Plugging an oil well lis not too much different, though operating it is, so there will be additional above ground structures and underground fixtures for an oil well.)   

In real life there may be more than one coal formation and there are likely also to be several additional gas formations above (and below) the target formation of the well in question. (Missing from this illustration is that the house may have a septic system that needs isolated from good groundwater.) 

    Next Slide

Back to Slideshow Index