5 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
Characteristics of the subjects (Fleurbaix-Laventie Ville-Santé II study).
<p>Values are expressed as mean ± standard deviation, or median and interquartiles. Data for leisure time and walking are from the Modifiable Activity Questionnaire.</p
Mother-offspring correlation for pedometer-assessed physical activity (Fleurbaix-Laventie Ville-Santé II study).
<p>Data are interclass correlation coefficients (95%CI) of number of steps standardized for sex and age. Data for physical activity during leisure time are from the Modifiable Activity Questionnaire. The total number of clusters can differ from maximal number of clusters (283) because of missing data.</p
Pedometer counts (steps per day) (Fleurbaix-Laventie Ville-Santé II study).
<p>Values are daily medians and interquartiles.</p
Familial correlations for pedometer-assessed physical activity (Fleurbaix-Laventie Ville-Santé II study).
<p>Data are correlation coefficients (95%CI) of number of steps standardized for sex and age.</p><p>Maximal number of clusters because for each coefficient computation data could be missing.</p