Use this simple gas in place calculator to calculate the total amount of gas contained in a reservoir and, as such, a higher figure than recoverable gas.
Formula:
G = 43,560 x A x h x φ x (1 - Sw) ÷ Bg × E
Where,A = area
h = net pay
φ = porosity
Sw = water saturation
Bg = gas formation volume factor
E = recovery efficiency