Date: Thursday, June
24,'04 Time:11:45 Hrs. Venue: Sasono Mulyo 2, Lobby Level Le MERIDIEN Jakarta
Subject:" Stratigraphic traps in the Tertiary Rift Basins of Indonesia: Case Studies and Future Potential"
Speaker: Chris Atkinson, Michael Renolds1 and Oskar
Hutapea2 ABSTRACT Since the early 1990’s stratigraphic traps have
become increasingly important in Indonesia with a number of major oil and gas
fields being found in the so called “mature” “over drilled” Tertiary rift basins
of Western Indonesia. In fact, it
is true to say, that over the last decade all the major discoveries (> 100
mmboe) in Western Indonesia have all been of a stratigraphic nature. A number of major companies walked away
from long-term concessions with no further structural trap potential, leaving
behind major oil and gas fields to be discovered by smaller independents who had
both the creativity to identify the stratigraphic traps and also the ability to
“sell” the concept to an enlightened management. The key to finding stratigraphic traps in the
Tertiary rift basins of Western Indonesia is really quite simple; define a
working petroleum system. The
similarities of the geology in Western Indonesian Tertiary rifts, and indeed the
Malay Basin right up into Onshore Thailand, is remarkable. Every rift has a similar history
beginning with a syn-rift phase, which primarily provides source rocks of
various types as well as reservoir sandstones. This is followed by a thermal sag phase
(“early post-rift”) where better quality reservoir sandstones and sometimes reef
carbonates are found. The ensuing
transgressive phase (“late post rift”) guarantees a marine shale regional
seal. This seal is most impressive
at the Minas Field in Central Sumatra where 6 billion barrels of oil are trapped
at only 600 metres depth with no surface oil seeps. The various late Tertiary “orogenic”
phases trigger migration of hydrocarbons generally up the flanks of the rifts as
well as creating structures at shallower levels. Sometimes this structural activity is so
intense that the regional seal is breached causing hydrocarbons to migrate into
these shallower structures where major accumulations have been found. However, where the seal is NOT breached
the hydrocarbons MUST still be trapped below it on the flanks of the rift. The giant Intan-Widuri (Maxus 1990) and
Kaji Semoga (Exspan 1993) fields are perfect examples. In
Western Indonesia there is no doubt that the “easy oil” has already been found
in large 4-way dip closures or classic Sunda Fold inversion structures. However, we believe that there is still
a huge potential for finding large reserves in stratigraphic traps in basins
with the right characteristics. In
this context, examples will be shown from the Asahan Offshore and Biliton PSC’s
where rift basins exhibiting these characteristics clearly exist but which
remain at the present day largely unexplored. BIOGRAPHY Chris
Atkinson is a founding partner in Serica Energy Corporation which currently has
assets in Indonesia (Asahan Offshore PSC, Biliton PSC, Lematang PSC), the UK
North Sea and Spain. Chris
has over 20 years of varied experience in the international oil and gas industry
of which 4 were spent in the early 1990’s in Indonesia where he was an active
member of the both the IPA and the IPA Professional Division.
Chris
obtained his BSc (First Class) and PhD in Geology from the University of Wales,
UK and joined Shell International at their KSEPL Rijswijk Research Laboratory in
1982. He moved on from Shell to ARCO in 1985 and spent a further 15 years
with ARCO in the USA, China, New Zealand, Indonesia and the UK. He held a variety of Senior
Management positions with ARCO and at the time of the BP takeover in 2000 was
the Exploration Vice President for Europe and North
Africa. Chris
is a current fellow of the Geological Society of London, and holds memberships
in the American Association of Petroleum Geologists, the Petroleum Exploration
Society of Great Britain, the South East Asian Petroleum Exploration Society and
the Indonesian Petroleum Association. FUTURE
TALKS Suggestions and volunteers for talks are always
welcome. Topics should be relevant to exploration and production in Indonesia
and/or be of interest to a wide range of disciplines. Please
contact the Luncheon Talks Chairman, Scott W. McFall, at BP, phone 7854-8185,
e-mail:[EMAIL PROTECTED] COST :
Rp. 125.000,00 (IPA Prof. Div. Member) or Rp. 145.000,00 (Non IPA Prof. Div.
Member) excluding drinks, payable at the entrance of the Sasono Mulyo 2
Room; payment in cash is preferred. ·
Reservations
and cancellations will be accepted until 15:30 hours on Wednesday, June 23,
2004. Phones: 572.4284-4286; fax: 572.4259; e-mail: [EMAIL PROTECTED] or [EMAIL PROTECTED] ·
No
reservations and cancellations will be accepted after this
time. ·
Members
of IAGI, HAGI and IATMI are welcome.
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