In my last column, I talked at some length about selecting screen openings and then ended up by describing one installation method: just driving a pointed screen into a water-bearing formation. Now, I am aware that in this day and age many screens are either threaded or glued directly to the bottom of the casing in a rotary hole. This certainly works, but if the screen has the wrong openings or fails for some other reason either at installation or later, it is impossible to pull. I’m going to limit my comments to screens that can be pulled and would be used in a cable tool or hollow rod drilled well.
Probably the most popular method of installation is the so called telescoping method—sometimes called the pull back method. In this method, the casing is driven down through the aquifer to where the drive shoe is at the target depth for the bottom of the screen on installation. The casing is cleaned out and it is a good idea to move through the formation in step. That is, drive a foot, clean out and drive another foot, and clean out and keep doing this until we get as deep as desired. Just driving the casing, say 5 feet for a 5-foot screen and then cleaning out is not a good idea.