Petroleum Plays Significance of Growth-Faulted Delta Systems : An Analog Flume Experimental Model of The Mio-Pliocene Sequence of Mahakam Area, East Kalimantan, Indonesia

Saputra, Isnianto¹; Fardiansyah, Iqbal²; Budiman, Agung²; Ramadhan, Aldis³; Gunawan, Adi⁴
¹Geological Engineering, UPN "Veteran" Yogyakarta, Sleman, Indonesia.
²Geopangea Research Indonesia, Sleman, Indonesia.
³Sedimentology & Petroleum Geology Laboratory UPN'Veteran"Yogyakarta, Sleman, Indonesia.
⁴Total E&P Indonesie, Balikpapan, Indonesia.

Growth-fault is a common feature in the delta system which controlled by gravity driven deformation. The presence of the fault not only complicates sequence-stratigraphic interpretation of delta successions both sides of the fault block, but also contributes for the occurrence of unique petroleum plays. This study is to demonstrate how the quantitative analogue flume modeling results can aid in understanding depositional architecture on system-tract scale to evaluate possible petroleum plays significance in growth-faulted deltas setting.

An example case that has taken as prototype for this modeling study is Spartan field that situated within Mio-Pliocene sediments of the Mahakam Delta, East Kalimantan, Indonesia. Practically, the flume experiment incorporated the combined effect of growth faulting as control of syn-depositional sediments. The spatial scale of the model, in conjunction with sediment-supply rate, result in a time scaling that models basin-fill processes that operated over more than 10 million years in 360 minutes of 4 sequences experiment. Each of empirical variables (i.e base-level estimated, subsidence and sea-level changes) have role as parameters to calibrate the experimental results, quantitatively.

As results, sedimentary successions on both sides of growth-fault were extremely different. The hanging-wall succession is characterized by lowstand, early transgressive, and highstand deposits while the foot-wall succession, in contrast, composed by late transgressive deposit, dominantly. Several petroleum plays significance has identified by the experiment. The incised-valley fill, point-bar, transgressive channel and crevasse-splay deposits have considered as reservoir facies which deposited during transgressive, lowstand and highstand events, respectively. Intraformational shale of early transgressive deposit, subsequently to maximum flooding event might be local and regional seals. The possible traps were coming from stratigraphic pinch-out, unconformity, and structural/stratigraphic trap mechanism. The conceptual model from the experiment provides useful analogs to describe potential components of petroleum plays in growth-faulted delta setting.

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