EXPLORATION IN THE NORTHERN BONAPARTE BASIN, TIMOR SEA - WA-199-P

1990 ◽  
Vol 30 (1) ◽  
pp. 7
Author(s):  
Mike Whibley ◽  
Ted Jacobson
Keyword(s):  
Late Jurassic ◽  
Fault Reactivation ◽  
Coarse Grained ◽  
3D Seismic ◽  
Submarine Fan ◽  
Oil Migration ◽  
Island Group ◽  
Main Period ◽  
Timor Sea ◽  
Exploration Phase

Permit WA-199-P, located in the Northern Bonaparte Basin, has undergone an intensive exploration phase from its award on 22 October 1985, which has resulted in the acquisition of 6250 km of 2D seismic and 1558 km of 3D seismic together with the drilling of seven exploration wells. Significant oil shows were recorded in six of these wells.The major play type investigated to date within the permit consists of Jurassic tilted horst and fault blocks. Potential reservoirs comprising medium to coarse grained sandstones of the Jurassic Plover Formation and, to a lesser extent, the Late Jurassic to Early Cretaceous Flamingo Group, are sealed by massive claystones of the Cretaceous Bathurst Island Group. Numerous oil shows have been encountered by drilling within these two reservoirs; however, drilling results from the Avocet-Eider structure indicate that Late Miocene-Recent fault reactivation often breaches the lateral seal of the fault- dependent structures causing leakage of hydrocarbons up the fault.Source extract-oil correlations and maturation studies indicate that the most likely oil sources comprise thermally mature marine claystones of the Flamingo Group and Plover Formation, developed within the Sahul Syncline to the east of WA-199-P. The main period of oil migration was probably Miocene or younger. A number of play types remain untested. These consist of Permian, Intra-Triassic and top Cretaceous fault blocks, as well as fault-independent closures, downdip fault closures and stratigraphic wedge outs of Maastrichtian sand reservoirs, and submarine fan sands developed within the basal Flamingo Group.

USING 2D AND 3D BASIN MODELLING TO INVESTIGATE CONTROLS ON HYDROCARBON MIGRATION AND ACCUMULATION IN THE VULCAN SUB-BASIN, TIMOR SEA, NORTHWESTERN AUSTRALIA

2004 ◽  
Vol 44 (1) ◽  
pp. 93 ◽  
Author(s):  
T. Fujii ◽  
G.W. O’Brien ◽  
P. Tingate ◽  
G. Chen
Keyword(s):  
Late Jurassic ◽  
3D Modelling ◽  
Source Rocks ◽  
Lateral Migration ◽  
Burial History ◽  
Oil Migration ◽  
Early Migration ◽  
Late Tertiary ◽  
Timor Sea ◽  
2D And 3D

2D and 3D basin models have been constructed of the southern and central parts of the Vulcan Sub-basin region, in the Timor Sea. This work was carried out to better elucidate the petroleum migration and accumulation histories, and exploration potential, of the region.2D/3D modelling in the Swan Graben indicates that horizontal and downward oil expulsion from the source rocks of the Late Jurassic Lower Vulcan Formation into the Plover Formation sandstone was active from the Early Cretaceous to the present day. Oil migration from the Lower Vulcan Formation into the Late Cretaceous Puffin Formation sands in the Puffin field was simulated by lateral migration along the bottom of an Upper Vulcan Formation seal and by vertical migration above the seal edge. Modelling also indicates that Late Jurassic sequences over the Montara Terrace are thermally immature, and did not contribute to the hydrocarbon accumulations in the region. On the other hand, 3D modelling results indicate that Middle Jurassic Plover Formation in the Montara Terrace became thermally mature after the Pliocene and hence it could contribute both to the hydrocarbon accumulations and the overall hydrocarbon inventory in the area.In the southern Cartier Trough, the Lower Vulcan Formation is typically at a lower thermal maturity than that seen in the Swan Graben, due to a combination of a relatively recent (Pliocene) enhanced burial history and a thinner Lower Vulcan Formation. Here, horizontal and downward oil/gas expulsion from the Lower Vulcan Formation into the Plover Formation sandstone was active from the Late Tertiary to present day, which is significantly later than the expulsion in the Swan Graben. Oil migration from the Lower Vulcan Formation into the Jabiru structure via the Plover Formation carrier bed, was simulated in both 2D and 3D modelling. In particular, 3D modelling simulated oil migration into the Jabiru structure, not only from the southern Cartier Trough after the Miocene, but also early migration from the northern Swan Graben in the Early Cretaceous.In the central Cartier Trough, the areal extent of both generation and expulsion increased as a result of rapid subsidence from about 5 Ma to present day. This Pliocene loading has resulted in the rapid maturation of the Early to Middle and Late Jurassic source system, and expulsion of oil very recently.

FAULT ARCHITECTURE ANDTHE MECHANICS OF FAULT REACTIVATION INTHE NANCARTROUGH/LAMIN ARIA AREA OF THE TIMOR SEA, NORTHERN AUSTRALIA

2000 ◽  
Vol 40 (1) ◽  
pp. 174 ◽  
Author(s):  
M.J. de Ruig M. Trupp ◽  
D.J. Bishop ◽  
D. Kuek ◽  
D.A. Castillo
Keyword(s):  
Late Miocene ◽  
Seismic Data ◽  
Fault Plane ◽  
Fault Reactivation ◽  
3D Seismic ◽  
Oblique Collision ◽  
Late Tertiary ◽  
Timor Sea ◽  
Fault Architecture ◽  
3D Seismic Data

Fault-bounded Jurassic structures of the Timor Sea have in recent years been the focus of intensive oil exploration. A number of significant oil discoveries have highlighted the exploration potential of this area (e.g. Laminaria, Corallina, Buffalo, Elang, Kakatua), but the majority of tested structures are either underfilled or show evidence of a residual oil column, resulting from trap failure of previously hydrocarbon-bearing structures. Recent well results confirm that trap integrity remains the principal exploration risk in the Timor Sea.Fault reactivation of Jurassic hydrocarbon traps is related to late Miocene-Pliocene oblique collision between the Australian plate and the SE Asian plate complex, which caused widespread transtensional faulting. The sealing potential of fault-bounded traps is, to a large degree, controlled by the orientation of the fault plane relative to the late Miocene-Recent stress field. However, the location of potential hydrocarbon leakage pathways remains difficult to define due to the complex fault architecture and a limited understanding of the interaction between Jurassic faults and Late Tertiary tectonism.During the past few years, a wealth of new exploration wells and 3D seismic data has become available from the Laminaria High/Nancar Trough area. The use of 3D visualisation tools, seismic coherency filtering and other seismic techniques has greatly enhanced our understanding of the fault architecture of this area of the Timor Sea.The structural architecture of the Nancar Trough/ Laminaria High is made up of several different structural intervals that are stratigraphically separated and partially decoupled along thick claystone intervals. Fault blocks at Jurassic level are typically overlain by Tertiary en-echelon graben systems, often showing characteristic 'hourglass' structures in cross-section. Detailed mapping of these fault structures on 3D seismic data has shown that the Jurassic faults and overlying Tertiary faults areoften partially decoupled.Fault throw distributions indicate that the Mio-Pliocene faults have grown downwards instead of Jurassic faults propagating upwards during reactivation. The two fault systems are soft-linked within Cretaceous claystones, only locally linking to form through-going faults. Hydrocarbon leakage pathways are most likely located at these points where critically stressed parts of Jurassic faults link up with Tertiary faults. The position of these linkage zones in relation to structural closure is key to understanding the distribution of preserved and breached columns that have been observed to date.The integration of 3D seismic fault plane mapping with in-situ stress analysis from borehole image and pressure test data provides a valuable tool for the evaluation of trap integrity, potential hydrocarbon leak paths and a more accurate risk assessment of exploration prospects.

THE ELANG OIL DISCOVERY ESTABLISHES NEW OIL PROVINCE IN THE EASTERN TIMOR SEA (TIMOR GAP ZONE OF COOPERATION)

1995 ◽  
Vol 35 (1) ◽  
pp. 44
Author(s):  
I. F. Young ◽  
T.M. Schmedje ◽  
W.F. Muir
Keyword(s):  
Seismic Data ◽  
Late Jurassic ◽  
Joint Venture ◽  
Seismic Survey ◽  
Normal Faults ◽  
Commercial Development ◽  
The North ◽  
3D Data ◽  
Porosity And Permeability ◽  
Timor Sea

The Elang-1 oil discovery in the Timor Gap Zone of Cooperation (ZOC) has established a new oil province in the eastern Timor Sea. The discovery well, completed in February 1994, recorded a flow of 5,800 BOPD (5,013 STBOPD) from marine sandstone of the Late Jurassic Montara beds. The oil is a light (56° API), undersaturated oil with a GOR of approximately 550 SCF/STB. Elang-1 was the first well drilled by the ZOCA 91-12 Joint Venture and only the fifth well in the ZOC since exploration of this frontier area resumed in 1992.The Elang Prospect, initially mapped by Petroz in the late 1970s on the basis of regional seismic data, was detailed by the 1992 Walet Seismic Survey. The prospect is the main crestal culmination on the Elang Trend, a prominent structural high to the north of the Flamingo High that was established during continental break-up in the Late Jurassic. The Elang Trend is bounded to the south by a series of en-echelon normal faults and connecting relay ramps and comprises a number of horst and tilted fault blocks.Elang-1 tested a near crestal culmination on the Elang Prospect and intersected a 76.5 m gross oil column below 3,006.5 m RT. At time of drilling this oil column was the thickest that had been encountered by any well in the Northern Bonaparte Basin. Good quality reservoir sandstone in six discrete bodies were intersected within the Montara beds. Core-measured porosity and permeability range up to 17 per cent and 2.2 Darcies within the oil column.Subsequent to the Elang discovery, the Joint Venture recorded a 402 km2 3D survey over the Elang Trend. Elang-2, an appraisal well spudded in September 1994 prior to receipt of the 3D data, established the lateral continuity of the Montara beds reservoirs. Flow rates of 6,080 BOPD (5,300 STBOPD) and 7,500 BOPD (5,970 STBOPD) from separate intervals have confirmed that high deliverabilities can be expected from individual sandstones. Further appraisal drilling is planned in the first half of 1995. This is expected to lead to commercial development of the field.

THE REGIONAL GEOLOGY OF THE BONAPARTE GULF TIMOR SEA AREA

1974 ◽  
Vol 14 (1) ◽  
pp. 77 ◽  
Author(s):  
Robert A. Laws ◽  
Gregory P. Kraus
Keyword(s):  
Late Cretaceous ◽  
Late Jurassic ◽  
Oil And Gas ◽  
Upper Jurassic ◽  
Structural Configuration ◽  
Structural Pattern ◽  
Source Areas ◽  
Timor Sea ◽  
Early Palaeozoic ◽  
Sea Area

The present structural configuration of the Bonaparte Gulf-Timor Sea area is essentially the result of Mesozoic and Tertiary fragmentation of a once relatively simple Permo-Triassic Basin. A northwest-southeast Palaeozoic structural grain in the southeastern portion of the area resulted from early Palaeozoic faulting, possibly tied to aborted rift development. This faulting effectively controlled sedimentation throughout the Phanerozoic. Pronounced northeast-southwest Jurassic to Tertiary structural trends dominate the central and northern area, paralleling the present edge of the continental shelf and swinging south southwest into the northern extension of the Browse Basin. Post-Palaeozoic epeirogenies which had the greatest effect on the regional structural pattern occurred in the mid-Jurassic, Early Cretaceous, within the Eocene and in the Plio-Pleistocene.The Kimberley and Sturt Blocks flanking the basin to the south and east constituted the most important source areas for clastic sedimentation throughout the Phanerozoic. Periodic contributions during the Mesozoic were derived from a postulated source to the northwest in the vicinity of the present-day Timor Trough.The maximum thickness of Phanerozoic sediments present within the Bonaparte Gulf-Timor Sea area exceeds 50,000 ft (15,000 m). Early Palaeozoic to Carboniferous evaporites, carbonates and clastics are unconformably overlain by a thick sequence of Permian deltaic sediments in the southeastern Bonaparte Gulf Basin. This is succeeded by a Triassic to Middle Jurassic transgressive-regressive clastic sequence, grading northwestward to marginal marine and marine clastics and carbonates. The Permian to mid-Jurassic sediments are unconformably overlain by Upper Jurassic sands and shales, mainly fluvial in the southeast and north, becoming more marine westward. These clastics are everywhere succeeded by a monotonous sequence of Cretaceous shales and shaly limestones followed by a generally north to northwesterly thickening wedge of Tertiary carbonates and minor elastics.Hydrocarbon shows have been noted offshore in rocks of Carboniferous, Permian, Late Jurassic, Late Cretaceous and Eocene age. Porous clastics in conjunction with thick and laterally-extensive, organically-rich shales are present within the Palaeozoic and Mesozoic sequences. These sediments, in association with fault- and diapir-related anomalies and stratigraphic plays, combine to make certain provinces of the Bonaparte Gulf-Timor Sea area prospective in the search for viable oil and gas reserves.

High resolution imaging of fault reactivation in long-lived extensional setting: a case study from the Exmouth Plateau (NW Australia)

2020 ◽  
Author(s):  
Nico D'Intino
Keyword(s):  
High Resolution ◽  
Confining Pressure ◽  
Data Interpretation ◽  
Fault Analysis ◽  
Fault Reactivation ◽  
Normal Faults ◽  
3D Seismic ◽  
Exmouth Plateau ◽  
Northern Carnarvon Basin ◽  
Nw Australia

<p>Extension in rift zones and passive margins often occur by multiphase normal faulting which usually accommodates several episodes of lithosphere stretching by brittle deformation. In these settings, pre-existing normal faults may reactivate but also new-formed structures may nucleate, with multiple orientations and deformational styles. The various modes of fault growth and nucleation are strongly influenced by several parameters (including orientation and geometry of pre-existing discontinuities, stress orientation and magnitude, strain rates, confining pressure, etc..) with the lithostratigraphy controlling the brittle or ductile litho-mechanic behavior of each unit.</p><p>In this work, we interpreted and analyzed an industrial 3D seismic volume acquired in the Exmouth Plateau, (Northern Carnarvon Basin – offshore NW Australia), where pre-existing Mesozoic normal faults were reactivated during the Cenozoic and controlled the nucleation and growth of the new-formed overlying fault segments. The peculiarity of this system is that the two sets of faults are separated by a ductile interval of shales. The latter acted as decollement level and promoted the formation of prominent faulted anticlines in the overlying brittle sequence; these forced folds are poorly documented in other extensional settings while are common where salt layers are present. In this study, the high-resolution techniques adopted for seismic data interpretation aimed to understand the geometries of faults and their interactions in fine detail. The results of fault analysis suggest that the use of high-quality 3D seismic volumes is very useful to unravel the complex and subtle spatial variability and also the displacement pattern of faults with a limited amount of fault-throw.</p>

Sign in / Sign up

Export Citation Format

Share Document