Petroleum Resource Exploration
8 PETRONAS
Figure 3.31: Criteria Used for Defining Group Tops of PM320
SEISMIC
SEISMIC ATTRIBUTES
SEQUENCE
AGE
Basement Pre-Tertiary
Poor resolution - Internal configurations or
patterns not very distinct
Orange
Late
Oligocene
Reflectors show moderate continuity and
moderate amplitudes.
Green
Early
Miocene
Reflectors are moderate to high continuity and
moderate to high amplitudes.
Tb2.2/2.3
PETROLEUM RESOURCE EXPLORATION
LOG
ATTRIBUTES
DEPOSITION OF
ENVIRONMENT
DESCRIPTION
DEPTH
Tampur Carbonate
1410m
Time equivalent to
Bampo/Parapat
formation
(claystone,
mudstone, shale).
Continental deposits of
sandstone, conglomerate
and claystone.
Syn-rift graben-fill deposit.
1180m
Time equivalent to
the Belumal
formation.
Marine Influence,
predominantly mudstone
with interbedded limestone
and sandstone.
Post-rift upper graben-fill
1103m
Late Early
Middle
Miocene
Parallel reflectors show generally high
amplitudes with moderate to high continuity
In general, top of reflector shows strong
reflector top.
On some lines, erosional cuts are clearly visible.
Good correlation
between log and
seismic, marking
the start and end
of sandy interval..
Shelf platform environment-
middle neritic Alternating
sandstone and shale
On lapping onto underlying
Green sequence. Distinct
erosional features visible.
Biostratigraphy indicates an
age gap of 9 Ma between
Tb2.2/2.3 to TB3-2/3.3.
Clear strong unconformity is
observed, indicating possible
sub-aerial exposure.
956m
Tb3.2/3.3
Middle-Late
Miocene
Tb3.5
Early
Pliocene
Parallel reflectors with low to moderate
amplitudes, with moderate to high continuity.
Parallel to sub-parallel relatively continuous
reflector, moderate amplitudes.
High gamma ray
values indicate
deeper
environment of
deposition than
Tb2.2/2.3
Predominantly shale with
silty sands. Mid Neritic
On-lapping onto Tb2.2/2.3
and minor erosional
truncations at the top,
881m
Shaly deposits, in shallow
outer entic
Lies conformably over
795m
Tb3.2/3.3.View entire presentation