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This paper consists of multiple approaches to develop a new model to determine the porosity, permeability, and rate of desorption of 1.5-in. shale samples. Permeability measurements of very tight rocks is difficult and uncertain, and no clear industry standard has yet been agreed upon. Therefore, this technique will investigate a new way to determine the porosity and permeability in shales. The raw NMR signal of the sample is measured before methane injection and is used as a base signal. During the injection of methane, the raw NMR signal increases. The base signal is subtracted from the response during the methane injection. This difference is inverted in multiple exponential distributions to only obtain the T 2 distributions and T 1 −T 2 correlations related to the injected methane in the shales. T 2 distribution holds information on the pore size distribution. Using cutoff values to separate the signal, different zones can be extracted. During injection and production of fluids, the rate and the total fluid filled porosity are used to calculate the permeability related to the individual pore size distributions. In the majority of shale gas formations, two types of pore systems are present; kerogen-hosted organic pores (OP) and inorganic pores (IP). By fully saturating 1.5-in. shale cores and by continuously measuring the NMR signal, it is possible to determine the individual porosity and permeabilities of the pore system. T 1 −T 2 measurements are made to confirm the individual zones and the mobility of the fluid in the zones. A single exponential decay formula is defined to calculate the permeability. This formula is tested with a reservoir simulation (using Eclipse) to validate the calculated value. Eventually a multiexponential model is used to distinguish the high and low permeability components in shales. This high permeability component is interpreted to represent the inorganic pores and microfractures, while the low permeability component is interpreted to represent the organic pores and the desorption from the pore surface. The Posidonia core samples show better production potential than the Qusaiba samples. Understanding the shale porosities for different storage mechanisms as well as the corresponding permeabilities is essential for developing shale reservoirs and target zone selection.

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