| CPC G01N 24/081 (2013.01) [E21B 7/04 (2013.01); E21B 47/022 (2013.01); G01N 33/241 (2013.01); G01N 33/246 (2013.01); E21B 2200/20 (2020.05)] | 20 Claims |
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15. A system, comprising:
a pressure cell;
a sample configured to be inserted into the pressure cell;
an NMR pressure and injection system configured to:
establish a predetermined measurement pressure within the pressure cell, and
create a gas saturated sample in the pressure cell; and
an NMR control and data acquisition system configured to:
acquire a baseline NMR spectrum of the pressure cell containing the sample;
acquire a saturated NMR spectrum of the pressure cell containing the gas saturated sample;
determine a differential NMR spectrum of the sample by subtracting the baseline NMR spectrum from the saturated NMR spectrum;
separate the differential NMR spectrum into an absorbed gas NMR spectrum and a pore gas NMR spectrum by performing a spectral deconvolution;
determine an absorbed gas NMR signal based, at least in part, on the absorbed gas NMR spectrum and a pore gas NMR signal based, at least in part, on the pore gas NMR spectrum:
acquire a normalization NMR spectrum of the pressure cell containing the gas saturated sample;
determine a gas calibration NMR spectrum based, at least in part, on the normalization NMR spectrum;
determine a gas calibration NMR signal based, at least in part, on the normalization NMR spectrum;
determine a mass of an absorbed gas and a mass of a pore gas based, at least in part, on the absorbed gas NMR signal, the pore gas NMR signal and the gas calibration NMR signal, and
determine a reservoir characteristic of the sample based, at least in part, on the mass of the absorbed gas and the mass of the pore gas.
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