WorldWide Drilling Resource

Environmental Monitoring by Thomas Kwader, Ph.D., P.G. Using Compressed Air to Remove Sediments from Developed Wells Well development is necessary to increase permeability of the borehole “well” and to remove fines to help produce clear, sediment-free water. There are many ways to develop wells - bailing, pumping, surging, etc. Well development involves the removal of unwanted fine materials along a newly drilled borehole and in the bottom of the casing. Surging the wellbore or well screen often produces a large amount of sediments which settle to the bottom of the well. These sediments can be difficult to remove using a bailer due to their depth; or if a pump is used, the silts and sands can destroy an expensive pump very quickly. Fifteen years ago, I patented a type of surge block used to develop small-diameter water wells. I’m often asked about how to remove the sediments from the developed wells. One of the most effective ways to remove sediments from the bottom of a well is using compressed air in a small-diameter conductor tube. For instance, a ½-inch air line in a 2- or 3-inch PVC or steel tube, in the following manner: 1. Insert the conductor tube (2- or 3-inch diameter) to the top of the sediments and secure the tube in place. 2. Insert a small-diameter (½-inch) rigid tube (PVC or steel) at least half the depth of the water in the well. 3. Pump air down the small-diameter tube to lift the water inside the conductor tube at a rate and pressure just enough to lift the water to land surface. A vacuum will be created in the conductor tube which will “vacuum” off the sediments in the bottom of the well casing. 4. Drill a ¾-inch hole in the elbow on top of the conductor pipe and insert the air line. The elbow will direct the water/sed- iment to the mud pit. Note: Do not use the well casing as a conduit unless it is less than 3 inches in diameter because the air will stream up one side of the well and not be able to lift the water through the large-diameter pipe. This method of air lifting creates a good vacuum using a small compressor (50 psi, 50 cfm) without damaging an expensive pump. This method can be used on any size well if the conductor pipe is 3 inches in diameter or less. Tom Tom Kwader may be contacted via e-mail to michele@worldwidedrillingresource.com ENV 28 JULY 2018 WorldWide Drilling Resource ®