Well points are perforated cylinders used to create shallow wells by driving the cone-shaped end of the well point into the soil instead of digging a well. A drive cap is screwed onto the threaded end of the well point before it is driven into the soil to prevent damage to the threads on the well point. Perhaps most troubling, it is very difficult to effectively seal a sand point well adequately meaning that contamination will always be a concern. Sludging. Sludging is an interesting and ancient method of installing a well that relies on a combination of teamwork and simple physics.