I don’t normally discuss ongoing projects here, but this time I wanted to share a current well project that might be of interest to a lot of people.
The well in question is approximately 700 deep and located in an area with known natural gas shows. The well was planned as a replacement production well for a medium-size water district. A local engineering firm was contracted to oversee the well design, drilling, and construction. This firm has an excellent reputation but does not have a lot of water well experience. I mean, it’s just a well, right? How hard can it be?
The new well was drilled and completed with minimal testing other than a pumping test. Everything checked out and it looked like they had a good well except they were getting a lot of methane intrusion into the well. So much, in fact, that the well is presently unusable. The engineering firm spent months trying to get the methane under control with little success. The old production well was shallower and had no methane issues, so the engineering firm finally proposed to just seal the bottom 350-400 feet with concrete to try to address the issue. It seems a bit desperate to just concrete up the lower half of an expensive new well when you have no idea where the methane is even coming from and this is where we got involved.
Our approach is to conduct vertical profiling of the well to identify the geologic zones where the methane is intruding into the well, categorize the high flow zones, and develop a plan to modify the well to seal off the methane zones while minimizing any impacts to the production capacity of the well.
So what could they have done differently from the outset? For one, understanding the geology of the area and potential contaminants you are likely to encounter is extremely important, as you can test for problems as you drill and even profile the test boring to design a well that will seal off problematic zones. It’s a lot less expensive to conduct the appropriate assessment during the test boring phase than to try to modify the well after it is already built.
The other thing that could have been done differently is to use the right diagnostic tools for the job. Just proposing to seal the entire bottom 350-400 feet of the well without any knowledge of where your problems are located is questionable, at best. Remember, it is more than “just a well.”