25th International Meeting on Organic Geochemistry IMOG 2011

P-033
An evaluation of petroleum source potential of fresh water
versus marine-influenced coals from Malaysian Tertiary basins
Wan Hasiah Abdullah 1 , Peter Abolins 2
1 University of Malaya, Kuala Lumpur, Malaysia, 2 PETRONAS Carigali Sdn Bhd, Kuala Lumpur, Malaysia
(corresponding author:wanhasia@um.edu.my)
An integrated evaluation was performed on 5 coal
samples from Malaysian Tertiary basins to assess
their oil-generating potential. These coals were either
deposited in a fresh water terrestrial setting or in a
marine-influenced paralic setting, two of the latter
being mangrove coals. Methods of assessment
include optical, physicochemical (FTIR and NMR) and
pyrolysis techniques (Rock-Eval and Py-GC).
The TOC of the analysed samples ranges from about
42-72 %wt, whilst the HI ranges from 101 to 560
mgHC/gTOC. All samples are either immature or
early mature for oil generation as suggested by the
vitrinite reflectance in the range of 0.42%-0.60%. This
low thermal maturity is supported by Tmax values of
404-431 0 C and strong yellow fluorescing liptinitic
macerals. All of the coals analysed are dominated by
vitrinite. Inertinite content are generally low (< 10% by
volume) and liptinite content varies from
approximately 10-40%. A rather poor correlation was
observed between liptinitic content and the HI values.
The aliphatic to aromatic ratios were obtained based
on NMR and FTIR fingerprints and show a reasonably
good correlation with C8/xylene ratio based on Py-GC
pyrograms.
This study indicates that marine-influenced mangrove
coals possess good oil-generating potential based on
high HI values (513-560 mgHC/gTOC) and supported
by the presence of n-alkene/alkane doublets.
Exsudatinite, bituminite and suberinite are common
liptinitic macerals of these mangrove coals and are
considered as the most oil-prone macerals within
Malaysian Tertiary basins. One of the mangrove coal
samples contains very high amounts of vitrinite
(approximately 90% by volume) thus suggesting the
oil-prone nature is also attributable to the vitrinitic
constituents.
Oil-prone mangrove coal dominated by vitrinite and
exsudatinite from a Tertiary basin of Malaysia; under
reflected ‗white‘ light and blue light excitation (field
width = 0.25 mm).
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