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Environmental Monitoring by Thomas Kwader, Ph.D., P.G. How Not to Develop a Well A few weeks ago, I received a call from a drilling contractor about a problem he was having developing a relatively shallow screened well, about 50 feet deep. He said he had drilled many wells in the area and felt there should be plenty of water in this formation, but the well was being “stubborn”. The water level was about 5 feet above the top of the 10-foot screen or about 35 feet below land surface. I asked if the well had been drilled with a gel-based drilling mud and was told it was not, so it was likely not a gel cake type of problem. After a few minutes of conversation, I could tell he was relatively new to drilling wells and was told to “get the mud out” of the screen by flushing 500 gallons of fresh- water quickly into the top of the well. Apparently, the idea is to “push” the mud out away from the screen and into the sand and gravel away from the wellbore. I thought about it for a few minutes and concluded this could work, but it was a risky thing to do. If the formation was very permeable, the mud cake could be pushed far enough away from the screen and conceivably work, but the well would soon turn “muddy” when the pump started pulling water back to the screen. I then recom- mended a surge block to break up the plugging and pull the drill mud back into the well, gradually. I would never recommend this method of development because of plugging the formation and taking a chance of not being able to retrieve the mud. Occasionally, you may need to “add water” to a new well to break the mud cake down, but not large amounts of water; only enough to promote a surging action, back and forth. However, you should pump or bail out more water than you put in the well to maintain a flow to the well - not away from it. Tom Tom Kwader may be contacted via e-mail to michele@worldwidedrillingresource.com 62 FEBRUARY 2016 WorldWide Drilling Resource ®