NMR apparatus and methods for measuring volumes of hydrocarbon gas and oil

A method for conducting NMR logging measurements, comprising:

• a. providing a data acquisition sequence comprising at least two sets of CPMG pulses having relatively short recovery times TWS1 and TWS2, respectively, and at least one set of CPMG pulses having relatively long recovery time TWL;
• b. receiving NMR echo signals from a population of particles in a geologic formation in response to the provided sets of CPMG pulses;
• c. processing the received NMR echo signals to determine a first and a second apparent volumes for at least one hydrocarbon fluid phase of the geologic formation, the step of processing comprising, forming a first difference signal EDIF1 by subtracting NMR signals having relatively short recovery time TWS1 from NMR echo signals having relatively long recovery time TWL and forming a second difference signal EDIF2 by subtracting NMR signals having relatively short recovery time TWS2 from NMR echo signals having relatively long recovery time TWL;
• and
• d. providing a data representation associated with the longitudinal relaxation time constant T1 of said at least one hydrocarbon fluid phase based on the determined first and second apparent volumes.