In case you were wondering why one might want stimulate a natural gas field using nuclear devices, here’s a quick and dirty primer.
Normally when you drill for natural gas, the gas should be able to travel through the underground rocks to the well. Although it’s rocky, it is porous, thus allowing for this flow.
However, not all underground formations are porous, some are tight, which means that although there may be lots of natural gas in the ground, the well that is drilled cannot access the natural gas.
In this case there are a couple of possibilities. Obviously you could just not drill and leave the natural gas underground and out of reach. However, in the 1950s, 60s, and on into the 70s, it was thought that the nation was facing a critical natural gas shortage and that it would be necessary to fracture the rocks in order to get out the natural gas. Nuclear stimulation is one way to get at the natural gas trapped in tight sandstone formations.
Of course, the result of nuclear stimulation is not quite that simple and easy. Somewhere in my research I found a diagram showing the components of a “rubble chimney, which is what results from detonating a nuclear bomb underground.
There were a lot of underground nuclear detonations. The first one experimentally detonated for peaceful purposes was on December 10, 1961. A 3 kiloton device was detonated 1,200 feet (approx 365 meters) below the surface, near Carlsbad, New Mexico. For comparisons sake, the bomb detonated over Hiroshima was approximately 18 kilotons.
At the top of the rubble chimney is a void:
Of course this photo of the void resulting from a 3 kiloton device is meaningless since there’s nothing indicating the scale.
For the record, the cavity was entered May 17, 1962, just over five months after the detonation. It was between 160 and 170 feet (48-52 m) in diameter, 60-80 feet (18-24m)tall. Temperatures up to 130F (55C) were found–as well as a few radiation hot spots.
Images shown here were acquired from two sources.
- The top three images were given to my by a professor at the University of Wyoming; I do not know where he acquired the images, however the ideas conveyed are simple enough that I doubt anybody owning the copyright cares. If you own the copyright (and can prove it) and want me to remove the top three images, please let me know.
- The remaining image and photograph were obtained from government documents and are, therefore, copyright free. I own the copyright for the information graphic drawn on top of the last photo. That said, you could probably make your own version of the last image easily enough, so feel free to use mine. I won’t object.