Total gas in place estimate

An system, comprising:

• a multifrequency dielectric dispersion measurement tool;
• a nuclear magnetic resonance (NMR) measurement tool;
• and
• a processor capable of performing the following operations:
• determining a mineralogy composition of a formation of interest using measurements on core samples or a downhole tool response;
• determining a dry permittivity for each identified mineral;
• employing a volumetric mixing law using the determined mineralogy composition and the determined dry permitivities;
• determining an effective matrix permittivity using results from the volumetric mixing law;
• acquiring dielectric dispersion measurements of the subject formation using the measurements on the core samples or the downhole tool response;
• producing a dielectric petrophysical model using the dielectric dispersion measurements and the effective matrix permittivity;
• estimating a water saturation based on the dielectric petrophysical model;
• acquiring nuclear magnetic resonance (NMR) T2 measurements having short echo spacings on the core samples or the formation of interest;
• generating a NMR petrophysical model based on the NMR T2 measurements;
• determining a total porosity based on the generated NMR petrophysical model;
• and
• making a total gas-in-place estimate using the determined total porosity and the estimated water saturation.