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Structural Evolution of Banda Arc, Eastern Indonesia: As a Future Indonesian Main Oil and Gas Development

Holis, Zaenal; Ponkarn, Agung S.; Gunawan, Agung; Damayanti, Shinta; Gunawan, Brahmantyo K.
Exploration Division, BPMIGAS, Jakarta, Indonesia.

In the last decade, exploration at Eastern Indonesia has been rapidly growth, as impact of energy demand. Banda Arc is a result of interaction of various plates as part of complex geological history in Eastern Indonesia. The movement of the Australian plate relative to Banda Sea is to NNE. Because of Banda Arc is curved, the angle of plate convergence should be changed along the arc. It caused different implication for structural deformation along Banda Arc. It is high oblique compressional in the Timor area, low oblique transpressional to the east of Tanimbar, and change from transpressional to transtensional in the area of Kai Islands.

Petroleum system is well developed in Banda Arc area. It is shown by some discoveries, including: Abadi Field, Bayu-Undan, Elang-Kakatua, Seram, Salawati Basin, and Bintuni Basin. Those discoveries come from Jurassic Sandstone and Miocene Kais Limestone reservoir. However, there are some unsucces exploration wells in Banda Arc area, which indicate there are some misinterpretations on petroleum system and structural. These unsucces exploration wells proved that structural restoration need to be conducted to explain unique structural evolution related to petroleum system development in Banda Arc. This research discuss the result of integrated study of 2D seismic interpretation and balancing cross-section, as part of structural geology evaluation in Banda Arc which concentrate in finding and determining kinematics relationship among different faulting events.

2D seismic interpretations were concentrated in recognizing structural pattern and kinematics. Balancing cross-section was concentrated in stable part area of Banda Arc where mostly successful exploration well existed. Based on palinspatic models made from 2D seismic, it indicated that deformation in stable area of Banda Arc shows group of contrasting strain features: early extensional faults forming the syn-rift deposit, reactivated by latter extensional structural style. Inversion structures evidence can be observed just only in thrust fault zone, unstable part area of Banda Arc. The strain axes consistently show maximum NE-SW direction of shortening in thrust fault zone, but doesn't show NW-SE direction of extension. Therefore, it concluded that both structures (extensional and shortening) were formed during different deformation phase. This interpretation would guide exploration well planning for better succes ratio in Banda Arc, Eastern Indonesia.

 

AAPG Search and Discovery Article #90155©2012 AAPG International Conference & Exhibition, Singapore, 16-19 September 2012