HYDROCARBON DISTRIBUTIONS
AND CARBON ISOTOPE
VARIATIONS IN THE SURFACE PETROLEUM OCCURRENCES
AND POTENTIAL SOURCE ROCKS
IN NORTHWEST LEYTE
RAYMUNDO A. REYES, JR.
ABSTRACT
Surface hydrocarbon occurrences and
potential source rocks in the north
western peninsula of Leyte were
subjected to vitrinite reflectivity,
organic-geochemical and carbon isotope
studies to establish geochemical trends
and probe possible genetic
relationships. Results indicate that (1)
land·derived organic matter has
contributed strongly to the potential
source materials of the Taog, Tagnocot
and Bata formations (2) the bitumen
impregnated in the sandstone members of
the Bata formation is not autochtonous
and must have migrated from a prolific
source rock (3) the surface hydrocarbon
occurrences originated from a common
source (4) biodegradation processes have
altered the seeps and bitumen in varying
degrees (5) the Taog formation has
relatively the best source potential and
maturity level for hydrocarbon
generation in the area. A certain degree
of correlation exists between the
surface shows and the Taog formation
although it is probable that the shows
have been derived from more mature
sections of the formation rather than
from the stratigraphic horizons of the
samples studied.
Geological
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