Patent ID: 8738295

Claim:
An empirical method for determining an adsorbed gas storage capacity of a shale reservoir comprising the steps of: extracting one or more shale samples from the shale reservoir at a plurality of depths; performing a rock eval pyrolysis on the one or more shale samples to determine a T max of the one or more shale sample, an S 1 of the one or more shale samples, and a TOC content of the one or more shale samples, wherein S 1 is an amount of free hydrocarbons in the one or more shale samples and wherein TOC is a total organic carbon (TOC) content of the one or more shale samples; empirically determining, based on the rock eval pyrolysis, a thermal maturity of the shale reservoir at each depth, wherein the thermal maturity is characterized as one of immature, oil zone, or gas zone, wherein the thermal maturity is characterized as immature if T max is less than about 435° C., wherein the thermal maturity is characterized as oil zone if T max is from about 435° C. to about 465°, and wherein the thermal maturity is characterized as a gas zone if T max is more than about 465° C.; empirically determining, based on the thermal maturity determination, a Langmuir volume (G sL ) of the shale reservoir at each depth, wherein the Langmuir volume (G sL ) is characterized by a first product (a·S 1 ) if the shale reservoir is characterized as oil zone and wherein the Langmuir volume (G sL ) is characterized by a second product (b·TOC) if the shale reservoir is characterized as immature or gas zone, wherein a is a constant from about 35 to about 38, and wherein b is a constant from about 19 to about 25; generating,via a computing processor, a synthetic adsorption isotherm, wherein the synthetic adsorption isotherm is a set of sorbed gas storage capacities corresponding to a range of desired pressures, wherein each sorbed gas storage capacity (G cs ) for a particular pressure (p) is determined according to the relationship, G cs = G sL ⁡ ( p p + p L ) , wherein p L is a Langmuir pressure of the shale reservoir; and providing an output of the synthetic adsorption isotherm to a user.