1 research outputs found
Characterization of Kerogen and Source Rock Maturation Using Solid-State NMR Spectroscopy
Solid-state NMR methods common to
the analysis of polymers and
other rigid solids are utilized for the study of kerogen, bitumen,
and the organic content in source rocks. The use of straightforward
nondestructive techniques, primarily employing solid-state NMR, is
shown to provide useful information about both individual samples
and changes between samples that cover a range of thermal maturities
of type II kerogen. In addition to aromatic fraction and chemical
structure, one of the most striking changes to isolated kerogen with
maturity is the distribution of pore sizes, studied with both <sup>129</sup>Xe NMR and complementary nitrogen physisorption, that may
help to understand the process of bitumen generation. Ultimately,
direct in situ analysis of source rock samples that allow kerogen
and bitumen to be distinguished is desirable, as it would eliminate
the time and effort to isolate and prepare kerogen samples. By proper
consideration and removal of the background, we find that a clear <sup>13</sup>C NMR signal can be obtained from source rock with total
organic carbon weight as low as 2%. Simple <sup>1</sup>H NMR methods
are shown to quickly provide a qualitative measurement of the bitumen
in source rocks, while <sup>13</sup>C cross-polarization is found
to be an easy method to distinguish kerogen from bitumen