High-Resolution
Sequence
Stratigraphy and Paleogeographic
Evolution of the Middle Miocene Gas-Bearing Successions in Northern
Mohamed Som, Mohd Rapi1, Abdul Hadi Abd Rahman2, Moh’D. Nurein Bushara3 (1) PETRONAS Research Malaysia, Bangi, Selangor, Malaysia (2) Universiti Sains Malaysia, Penang, Malaysia (3) PETRONAS Carigali Sdn Bhd, Kuala Lumpur, Malaysia
High resolution sequence
stratigraphic
analysis
and interpretation, based on the facies
description,
log
analysis
and paleoenvironmental
interpretation, identified major
sequence
boundaries and sequences within the E
and D Groups (Middle Miocene) of the northwest of
sequence
boundaries (E-10SB, E-8.2SB,
E-7.1SB, E-6.6SB, and E-6.5SB) and five sequences are recognized within the E
Group, and another five
sequence
boundaries (D-60.2SB, D-36.3SB, D-36.2SB,
D-34.2SB and D34.1SB) and five sequences within the D Group.
The succession
of sequences of the E-D-B Groups is the product of multiple cycles of relative
sea-level fall and rise onto an incised valley. The E Group forms the Early Transgressive Interval, and comprises at least five
high-frequency sequences (4th order?) of LST-TST-dominated, fluvial sequences.
The Late Transgressive D Group was deposited as the
result of relative sea-level rise. The inundation of the incised valley
resulted in the development of an estuary at the beginning of Sequence
D1, reaching
its maximum size during the deposition of
Sequence
D5. The Regressive Interval
(the HST) of the incised valley is partly or completely absent. It may have
been eroded during the rapid regression marked by the fluvial-dominated,
delta-forming system of the B Group. These paleogeographic
facies models and
sequence
stratigraphic
interpretation may be utilized as working models for future
well
planning.