By Jinhong Chen
Petrophysical parameters of a reservoir must be known for accurate estimation of the hydrocarbon-in-place and production. For unconventional organic-rich reservoirs, the industry standard method, developed by Gas Research Institute (GRI), is invasive and time consuming. A new method which uses the combination of nuclear magnetic resonance and gas-porosimetry (CNG) was proposed and used to measure porosity, bulk and grain densities, and irreducible liquid of source rocks. The method performs measurement on intact core plugs, in contrast to the GRI method which uses crushed samples. CNG was verified by comparing the measured results with GRI on 104 preserved cores from a source rock reservoir. From the experimental data, CNG provides similar or more accurate results but with multiple significant advantages over GRI: CNG is non-destructive and non-invasive to the sample; it is a much faster method; and it requires a much smaller amount of sample than GRI.