The answer would depend upon where your 20 acres are located in the section. There are five producing wells in the section. Some are spaced to the northern half of the section and some are in the southern half of the section. They were drilled between 1990 and 2008. They are gas wells, so several could last a long while if properly maintained. A couple of them do not look as healthy. The value would be based upon the price of gas at the time of purchase and the predicted price of gas out into the future, the net acres and the royalty. A general rule of thumb would be an average of the last seven years of production adjusted for price. These are conventional wells and not horizontal wells.
Future potential might be for horizontal drilling. There are horizontal wells in the sections nearby.