Lower Miocene carbonate mudbanks in the Ramba-Rawa area, south Sumatra basin, Indonesia

Conference · Mon Feb 01 00:00:00 EST 1988 · AAPG (Am. Assoc. Pet. Geol.) Bull.; (United States)

OSTI ID:5953919

Longman, M W; Zeliff, C W; Beddoes, Jr, L R

Micrite-rich skeletal wackestones and packstones with common branching corals and benthonic foraminifera form the reservoirs in the Ramba and Rawa oil and gas fields. These limestones are part of the lower Miocene Batu Raja Formation, a widespread carbonate unit deposited over much of southern Sumatra and the Sunda Shelf on a relatively stable carbonate shelf. Forty cores from the roughly 100 km/sup 2/ Ramba-Rawa area reveal that the reservoir rocks are part of a carbonate mudbank complex that formed on and around a basement paleohigh. The carbonates range in thickness from 12 m on the paleohigh to 65 m off the paleohigh and represent at least two periods of deposition separated by a time of subaerial exposure. Micrite and fragmented fossil debris dominate the reservoir rocks. In-situ corals are rare and limited to a few small colonies. No evidence exists of a rigid reef framework or marine cementation. Instead, the sediments accumulated as micrite trapped by sea grass and/or noncalcareous algae in low-relief banks in a shallow marine environment. Deeper water clay-rich tight wackestones containing planktonic foraminifera and glauconite surround the carbonate mudbanks. Porosity in the reservoirs is dominantly secondary and formed during dissolution and neomorphism of grains and matrix. Permeability is sufficient that the Ramba A and B pools produced 30 million barrels of oil during their first four years on production. Oil production in the Rawa area will begin in early 1988.

• OSTI ID: 5953919
• Report Number(s): CONF-880301-
• Journal Information: AAPG (Am. Assoc. Pet. Geol.) Bull.; (United States), Vol. 72:2; Conference: Annual meeting of the American Association of Petroleum Geologists, Houston, TX, USA, 20 Mar 1988
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
INDONESIA
NATURAL GAS FIELDS
OIL FIELDS
RESERVOIR ROCK
GEOLOGY
CARBONATE ROCKS
GEOLOGIC TRAPS
LIMESTONE
MIOCENE EPOCH
PERMEABILITY
POROSITY
ASIA
CENOZOIC ERA
DEVELOPING COUNTRIES
GEOLOGIC AGES
GEOLOGIC DEPOSITS
ISLANDS
MINERAL RESOURCES
NATURAL GAS DEPOSITS
PETROLEUM DEPOSITS
RESOURCES
ROCKS
SEDIMENTARY ROCKS
TERTIARY PERIOD
020200* - Petroleum- Reserves
Geology
& Exploration