NMR LOGGING OF NATURAL GAS IN RESERVOIRS.

摘要

A method is disclosed to determine a characteristic of a porous earth formation containing hydrocarbon gas, the earth formation being penetrated by a wellbore. The method comprises the steps of obtaining an NMR log using a recovery time that is equal to or greater than the longitudinal relaxation time of the hydrocarbon gas, and determining from the NMR log a distribution of transverse relaxation times including transverse relaxation times attributable to the hydrocarbon gas. Subsequently at least one of the pore size of the earth formation and the pore volume that is occupied by hydrocarbon gas is estimated.