Depositional Facies of Plover Formation in The Abadi Field, Eastern Indonesia based on Core Sedimentology

Aswan, Aswan¹; Zaim, Yahdi¹; Kihara, Koichi²; Hadianto, Kukuh³; Pemberton, George⁴
¹Geology, Institute of Technology Bandung (ITB), Bandung, Indonesia.
²INPEX Masela, Jakarta, Indonesia.
³Divisi Pengkajian & Pengembangan, BPMIGAS, Jakarta, Indonesia.
⁴Dept. of Earth and Atmospheric Sciences, University of ALBERTA, Edmonton, AB, Canada.

A core sedimentology study was made on the reservoir interval of the Middle Jurassic Plover Formation of the Abadi Field in Eastern Indonesian water, to establish a facies and depositional model of the field. The Plover Formation consists of complex siliciclastic sediments. The sedimentological description and analysis was done on the conventional cores (20 cored intervals with total core recovery of 172.3 m) in the six wells.The cores are rich in ichnofossil content. From the observation, six lithofacies (LFs) were interpreted based on the lithology, primary/ secondary sedimentary structures and ichnofossil assemblages:

- LF-1, which consists of massive and amalgamated quartzoze sandstone with cryptic bioturbation, is interpreted to have deposited in estuary channel.

- LF-2, which consists massive and structureless quartzoze sandstone with more marine ichnofossils such as Chondrites, Phycosiphon, Scolicia, Skolithos, is interpreted to have deposited in shore bar.

- LF-3, which consists of alternating fine sand and siltstones with parallel lamination and planar cross stratification, and common small Chondrites, Palaeophycus, Planolites and Thalassinoides. Is interpreted to have deposited in protected marine.

- LF-4, which consists of inter-laminated mudstone and thin layers of siltstone with parallel lamination, and with small Chondrites, Planolites, Ophiomorpha, and Thalassinoides ichnofossils, is interpreted to have deposited in more basinal part of protected marine than LF-3.

- LF-5 is consisted of alternating fine to medium sandstone/ siltstone/ mudstone with parallel lamination, wavy and flaser structures, and local tempestite structures. LF-5 has highly burrowed ichnofossils such as Phycosiphon, and Scolicia, with Asterosoma, Bergaueria, Chondrites, Cylindrichnus, Diplocraterion, Lockeia, Rhizocorallium, Rosselia, Skolithos, Thalassinoides, Teichichnus, and Trichichnus. This lithofacies is interpreted to have deposited in shoreface.

- LF-6 is consisted of interbedded of siltstone and mudstone with slump/ load cast/ disorganized structures, graded bedding, laminated and cross laminated lithoclasts deposited as gravity flows/ turbidite. No ichnofossils are found. This lithofacies is interpreted to have deposited in prodelta.

Stratigraphic correlation of the wells shows that all sandstones of Plover Formation are connected each other, but this study indicates that it can be a complex amalgamation of the variety of lithofacies/ depositional facies.

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