Hi Hicks, They have injection oil wells in our area that sound like a 747 stuck in first gear. It's a large diesel engine pumping air into a well so pressure on other wells in the unitized field is improved. They build a wall about 15 or 20 feet high around them, usually on two sides only. I'll see if I can drive into one and see what its made of. From the road it looks like a simple wooden wall.