Ah -- OK. Here in Nevada, we call that "air lifting" a well. Same idea in irrigation wells, just a larger scale.

The drillers will put two concentric pipes down into the bottom of the well -- a 8" OD pipe (remember, the cased diameter of an irrigation well is usually 16" ID), with a 4" OD air pipe. Set the two pipes so that the bottom end of the 4" OD pipe is about 6 feet higher than the bottom of the 8" OD pipe. Obviously, there's a bit of custom fitting needed at the top of this column of concentric pipe to get the water out of the 8", and the air into the 4" while hanging it all off a pump setting truck or a drill rig.

Start up a big honkin' air compressor up top and push the air down the 4" line to the bottom. Something like a big IR or Dresser compressor -- about 70HP diesel driven, 100's of CFM, does the job.

Up comes a whole lot of water, sand, gravel, etc. It is how we clean out wells after casing them so as to not use an expensive turbine pump to suck out all the sand and gravel.

It works pretty well, but on a HP for gallons lifted basis, it's an expensive way to bring up water.