Journal of Applied Geology, vol. 2(2), 2017, pp. 94–108 DOI: http://dx.doi.org/10.22146/jag.39988 Basin Evolution Palispatic Model of Bonaparte Basin, Australia Northwest Shelf Nomensen Ricardo,∗ Hendra Amijaya, and Salahuddin Husein Department of Geological Engineering, Faculty of Engineering, Gadjah Mada University, Yogyakarta, Indonesia ABSTRACT. This research area is located on the Australian NW Shelf close to the western edge of the Sahul Platform. This research is aimed to generate the palispatic basin model of Bonaparte Basin, Australian Northwest Shelf. It is to predict the impact of Neogene col- lision on the petroleum system distribution on Australian Northwest Shelf. The main data used in this research are seismic data using qualitative method analysis. The well data is used to well-seismic tied. After data acquisition, the seismic data are interpreted based on the horizon and structure interpretation. These interpretation are to reconstruct the basin evolution thorough geologic time. According to data analysis, the basin evolution pal- ispatic model are divided into Paleo-proterozoic, Paleozoic, Triassic, Early Jurassic, Mid- dle Jurassic, Late Jurassic, Early Cretaceous, Late Cretaceous, Early Eocene, Late Miocene and Recent condition. Regional tectonically there are at least three important events in NW Shelf: Middle Triassic-Jurassic NNE–SSW extension phase, Late Jurassic NE–SW ex- tension phase and the Neogen collision phase; the Neogen collision effects on Northwest Shelf Australia. These three events contributed in forming and disturbing the Paleozoic and Mesozoic petroleum system in Bonaparte basin especially. Keywords: Neogene collision · Basin evolution · Palispatic model · Petroleum system · Australian northwest self. 1I NTRODUCTION blocks and horst. This platform plunges to- Australian Northwest Shelf consist of 4 major wards the Southwest. The thin sediments of basins: the Northern Carnavon Basin, the Off- Perm, Triassic and Jurassic were deposited on shore Canning Basin, the Browse Basin and the Sahul Platform and progressed to the northeast. Bonaparte Basin or unitedly known as the Wes- It is estimated that this platform was formed tralian Superbasin / WASB (Yeates et al., 1987), due to Paleozoic openings that later rejuve- which is a field producer Large gas (reach- nated and lifted during the continental break- ing 84% of total Hydrocarbons) in addition to up event in Mesozoic and followed by a plate condesate and oilThere were 754 exploration collision of Australia with microplate Southeast drilling had bored at 233 Oil and Gas Fields in Asia at the end of Cenozoic. Two great Jurassic Australian North West Shelf basins.Australian Deposits to the Early Cretaceous identified in Northwest Shelf basin is estimated containing the Northern Bonaparte Basin, Malita Graben an oil reserve of 2.6 billion barrels, a condensate and Sahul Syncline. The collisions of the Aus- of 2.6 billion barrels and 152 tcf of gas. tralian and Eurasian Plates in the Miocene to The Sahul Platform, the northern part of Aus- the Pliocene resulted in a flexural down warp tralian basin, is defined as a large eastward on the Timor-Tanimbar Trench and resulted in trending basement that consists of tilted fault the reactivation of the Northwest Western Aus- tralian Margin. ∗ Corresponding author: N. RICARDO, Department The study area is located on the Australian of Geological Engineering, Gadjah Mada Univer- NW Shelf (Figure1) close to the western edge sity. Jl. Grafika 2 Yogyakarta, Indonesia. E-mail: of the Sahul Platform. To the north, the area is [email protected] 2502-2822/ c 2017 Journal of Applied Geology BASIN EVOLUTION PALISPATIC MODEL OF BONAPARTE BASIN bounded by the Timor Trough with a NE–SW est rocks in Banda Forearc, extrapolation to trend. At thepresent day the Australian plate is the northwest of the Australian Margin Graben being subducted beneath the SE Asian margin system passes through West Timor and this and the northwestern part of Australia is cur- aulacogen clearly has a strong influence in the rently in collision with the Banda Arc in the area sequence of structural development at subse- around Timor Island (Hamilton, 1979). quent riftings. The second phase of rifting These studies have utilised predominantly spanned the Late Carboniferous-Early Permian 2D seismic data and have been concerned with continuing throughout the Permian, to the early petroleum exploration. The area discussed in mid Triassic. This rifting phase is associated this study is relatively understudied in compar- with the development of an intracontinental ison. The main focus here is the structural con- rift along the Southern Banda Band (Timor- figuration and an understanding of structural Tanimbar) line, with the North Banda Busur evolution of the northern Bonaparte Basin. (Buru-Seram) Island which is the northern rift margin. The third phase of openings occurs 2M ETHODOLOGY at the End of the Triassic. The major rifting The seismic lines of 11602 and 11609 are used phase is identified between the late Mid Juras- to generate the basin history/ evolution - sec- sic and Early Cretaceous. It had been well docu- tion through geologic time. Both of these lines mented by Pattillo and Nicholls (1990); Colwell intersect each other and have a reliable marker et al (1994). This rifting phase is associated with of Flamingo Well. All horizons we have are the opening of the ocean floor that occurs dur- elaborated using flattening features on Decision ing Oxfordian and Valanginian and continues Space Geoscience (DSG) Software. As the re- with the development of the Indian Ocean and sult, we have the model of the basin and its de- the passive continental margin of Western Aus- velopment from basement (Paleo-Proterozoic) tralia. to recent sequences. Seismic cross section used The intra-Valanginian regional unconformi- is 2D seismic which has medium to good qual- ties showed the absolute top of the pre-breakup ity. Mistie adjustment is also done before be- sequences around the Banda arcs, though post- ginning the interpretation of the seismic cross breakup succession is partially equivalent to section. Reliable section is used as a reference the Late Jurassic on the northern Banda Arc for mistie analysis. Based on the results of this (Audley-Charles et al., 1979; Kemp and Mogg, analysis, some vintage should be shifted and 1992). While pre-breakup succession is char- adjusted to the vintage reference. acterized by sedimentary rock deposited in a All visible structures and horizons are inter- rifted continental margin environment, Banda preted based on seismic section through time Forearc post-breakup succession is character- geologic. Each horizon has a unique geologic ized by deep sea sediments that are deposited event. The product of these horizon and struc- on the outer shores of Australian continental. ture is a subsurface map. The Triassic time is The marine sediment (range in Cretaceous to the focused sequence in this research. The flat- Tertiary) has the potential to contain hydrocar- tening applied that are useful in basin evolution bons. The Perm rifting phase until the Early reconstruction. All horizons flatten at each time Triassic / Medium is the most significant de- to show the change of basin geometries. veloping structure, leading to the modifica- tion/evolution of the graben basin and inter- 3R EGIONAL GEOLOGY vening in the height of the horst block. As Metcalfe (2006) has explained in detail the evo- already mentioned, the northern and south- lution of the Australian Northwest Shelf basin. ern Banda Arcs developed as a complementary The initial phase of regional extensions are as- rifted margin during this period. sociated with the major aulacogenic rift, Bona- parte Graben (Petrel Sub-Basin), which devel- 4R ESULTS AND DISCUSSION oped during the Middle Paleozoic (Gunn, 1988; 4.1 Horizon interpretation O’Brien et al., 1993). Although the Bonaparte Horizon interpretation defines as identifying rifting phase is recognizably older than the old- the sequence/strata using geologic time datum. Journal of Applied Geology 95 RICARDO et al. Figure 1: Basemap of research area: Australian Northwest Shelf. The datum is distributed to other seismic sec- Middle Jurassic (Callovian) sequence. That is tion to estimate the development of strata later- consistent to well-seismic tied analysis which ally to the unknown/ unexplored area or some- shown Jurassic (middle) is the oldest sequence times call as stratigraphy seismic. Furthermore, penetrated by Flamingo Well in Sahul Syncline, the stratigraphy seismic is difficult to apply to NW Shelf Australia. Applying Flamingo well Northwest Shelf Australia – Timor and Tanim- marker, so the seismic section of 11602 and bar island geologic setting. The geology struc- 11609 are interpreted as shown on Figure2. tures developing in this research area are very The horizon picking was accomplished at some complex and complicated. Some horizons inter- geologic time from Proterozoic to recent con- preted are seismic section of 11602; 11603, 11608 dition. They are grouped into, Paleozoic se- and 11609. These section are representation of quence, Triassic, Early Jurassic, Middle Juras- all seismic that interpreted for subsurface map- sic, Late Jurassic, Early Cretaceous, Late Creta- ping. Totally, there are more than 30 line seis- ceous (Turonian), Early Eocene, Late Miocene, mic are interpreted. But some of them are not Recent. At Early Paleozoic, sediment filled the necessary. The limitation of well data and the rift basin and directly underlying Proterozoic distance of seismic line to Timor-Tanimbar area basement. The Triassic sequence overlying on are considered in determining/ selecting seis- Paleozoic sequence as a post-rift sediment in- mic line used in this research. In this term, a filling. Triassic sequence overlying on Paleozoic Flamingo well that located in Northwest Shelf sequence as a post-rift sediment infilling. At the Australia, is the only one trusted time geo- late Triassic as a Maximum flooding surface is logic marker used and applied to seismic sec- identified (Longley et al., 2002). This sequence tion. Seismic section NW–SE 11602 and NE–SW is dominated by fine clastic sediments.