A method is provided to estimate the pore volume of a formation occupied by hydrocarbon phase or phases, the method comprising the steps of: obtaining a first pulsed NMR log of the formation, the pulse sequence of the first NMR log comprising an initial 90 DEG radio frequency pulse, followed by a series of 180 DEG radio frequency pulses starting at a time period tcp1 after the initial 90 DEG pulse, and the series of pulses comprising magnetic pulses each separated by a time period 2tcp1; obtaining a second pulsed NMR log of the formation, the pulse sequence of the second NMR log comprising an initial 90 DEG radio frequency pulse, followed by a series of 180 DEG pulses starting at a time period tcp2 after the initial 90 DEG pulse, and the series of 180 DEG pulses comprising radio frequency pulses each separated by a time period 2tcp2 wherein the time tcp2 is a time that is different from tcp1 by an amount of time sufficient to separate resultant peaks of transverse relaxation times attributable to the hydrocarbon phase or phases within the formation; and determining, from the first and the second NMR logs, the pore volume of a formation occupied by hydrocarbon phase or phases within the formation. In a preferred embodiment, pore volume occupied by hydrocarbon gas is determined, and tcp2 is a time that is greater than that which results in the measured transverse relaxation time of the hydrocarbon gas being less than about 2x10-3 seconds and tcp1 is a time that is less than that which results in the measured transverse relaxation time of the hydrocarbon gas being greater than about 4x10-3 seconds.