Do you always see an increase in gas flow after dewatering, and what factors affect it?

Not always. We generally see some increase in gas flow, but the amount of increase can vary. It’s dependent on how long the gas well was watered in. If the gas well has been watered in for a fairly long period of time, the accumulation of biosolids and biomass as well as silt within the gas well can control whether or not we can get that well to perform at its previous levels. A couple of papers published on this subject have shown that gas flow increases can range all the way from a 100% original gas output to as much as 20% to 30% of original gas output. If a site is considering using pumps to improve gas collection, there needs to be a measurement of the liquid levels in the existing wells to determine how much of the perforated section of the well is currently exposed.  For example, if you have a well with 30 meters perforated pipe and 20 meters of that pipe are currently watered in, you can do a gas flow test on the existing open portion of the screen and get an estimate of how many cubic meters of gas per hour can be produced with the existing portion of the screen. From there you can estimate how much additional gas might be produced by dewatering. Try to use a conservative factor because it’s not very linear. For example, if we got to 20 cubic meters of gas per hour from a given well and we had two thirds of the well watered in, we might be able to raise that to 30 to 35 cubic meters by dewatering. We may not get as high as 50 or 60 cubic meters per hour.