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Kutai Basin Deep Marine Sediment Outcrops in Sepaku-Gitan Area, East Kalimantan, Indonesia: Reservoir Analogues to the Makassar Strait Deep Water Blocks

Bachtiar, Andang 1
1 Exploration Think Tank Indonesia, Jakarta, Indonesia.

Besides famous for its Mahakam Deltaic reservoirs, Kutai Basin - Indonesia - also has deep marine sand deposits producing hydrocarbon in Makassar Strait deep-water blocks. The shift of exploration mode toward the deep-water area of Kutai Basin in the last decade has amplified the significance of having analogues of marine deposits genuine to the basin. Lower Miocene Pamaluan and Pulaubalang Formations in Sepaku and Gitan areas in the onshore southwest corner of the basin serve as perfect examples of ancient Kutai deep marine sedimentation models.

Series of west-ward facing NNE-SSW thrust faults containing mini-synclines with outershelf- bathyal N4-N5 sediments of Pamaluan Formation in Sepaku-Gitan area are interpreted to be originated from toe-thrust faulting system developed on the shelf edge area active during Lower Miocene. The paleo toe-thrust faults were resulted from the Adang mega-shear reactivation, which were coupled by its pair to the north, i.e. the Mangkalihat mega-shear.

There are three types of deep marine sedimentation models proposed for Kutai Basin in association with the paleo-Mahakam Delta and the coupled Adang-Mangkalihat tectonic activity; i.e.: prodelta turbidite, middle-shelf storm-induced turbidite, and continental slope turbidites, which includes ponded deposits controlled both by excessive sedimentation load in the delta and Adang-Mangkalihat tectonics.


AAPG Search and Discovery Article #90090©2009 AAPG Annual Convention and Exhibition, Denver, Colorado, June 7-10, 2009