A gas producing formation has uniform thickness of 32 ft, a porosity of 0.19 and a connate water saturation of 0.26. The gas deviation factor is 0.83 at the initial reservoir pressure of 4450 psia and reservoir temperature of 175F. The reservoir happens to be consists of several isolated fault blocks. a) Calculate the initial in-place gas in one of the blocks whose area is 1420 acre foot of the bulk reservoir rock. b) How many years will it take a well to deplete by 50% a block of a 640-acre at a rate of 3 MM SCF/day? c) If the reservoir is under an active water drive so that the decline in reservoir pressure is negligible, and a the production of 40.5 MMM SCF of gas is obtained from the block of 1420 acres until it is fully invaded by the water, what is the residual gas saturation in that block?