WorldWide Drilling Resource

21 WorldWide Drilling Resource ® APRIL 2014 Environmental Monitoring by Thomas Kwader, Ph.D., P.G. You are never too old to do dumb things... Although I don’t think I’m that old, I am noticing more and more I’m the old- est person in a group or meeting. It really doesn’t bother me. But, it seems to me, the older you get the more experience you would have and tend to do fewer “dumb” things. Every July I conduct an injectivity test on a small, permitted well in the midwest. This test is to monitor the annu- al efficiency of the well and make sure the well is not plugging from biological activity or chemical reactions that would tend to “plug” the formation. The well is about four years old and has been per- forming well (no pun intended), so well the water level “free falls” at about 20 gallons per minute and never rises to ground level during the 24 hours of injec- tion testing. In previous years of testing, I always sealed the hole where the transducer cable enters the wellhead. The problem has been, at the end of the test, the epoxy-type putty used does not want to come off the cable when the test is over. Usually, I use a razor knife and scrape very carefully - like a surgeon. I have been afraid of “nicking” the cable, so this last year I did not seal the hole, which left a one-quarter-inch hole around the cable. The test ran smoothly with the transducer, set at approximately 200 feet below land surface for the entire 24 hours. The water level (or head) was meas- ured at 44 feet below land surface just before the flow into the well was stopped. Then what happened next, in the middle of that cornfield, cannot be described in words. Apparently, “quite a bit” of air was sucked into that little hole over those 24 hours. All of the air sucked into the well formed a large bubble at the bottom of the casing. When the test was over, the air started “lifting” the water out of the tubing, faster and faster. The well burped and hiccupped and began to spray violently out of that little hole. The pressure got higher and higher and was spraying upwards of over 100 feet high. I was sure the wellhead was about to be launched to the moon. After about 15 minutes, the pressure died down. Thankfully, nothing exploded and no one was hurt. The last reading on the pressure transducer before it maxed out was 540 psi. If I’m allowed to come back this year, I will plug that hole and have learned not to ever do that again. Tom Tom Kwader may be contacted via e-mail at admin@ worldwidedrillingresource.com