The prospectivity of the Cape Vogel Basin, Papua New Guinea

2019 ◽  
Vol 59 (2) ◽  
pp. 840
Author(s):  
Said Amiribesheli ◽  
Andrew Weller
Keyword(s):  
Petroleum System ◽  
Source Rocks ◽  
Magnetic Data ◽  
North West ◽  
Late Mesozoic ◽  
Gulf Of Papua ◽  
Differential Uplift ◽  
Uplift And Erosion ◽  
Cenozoic Sediments ◽  
Gravity And Magnetic Data

The frontier and underexplored Cape Vogel Basin (CVB), north of the Papuan Peninsula, is thought to be underlain by Late Palaeocene–Eocene oceanic crust and overlain by Cenozoic sediments. Several impartial data provide evidence of working petroleum system(s) including a flow of oil from a 1920s well, and two 1970s wells that encountered minor hydrocarbon traces and good source material. The 1970s wells chased Miocene reef plays (like the discoveries in the Gulf of Papua). No Miocene reefs were encountered, with both wells terminating in volcanics. Integration of open-file 2D seismic, modern 2D PSDM seismic and shipborne gravity and magnetic data improves the subsurface imaging and thus understanding of prospectivity. The data reveal a significant sedimentary section (including Mesozoic sediments) and that the volcanics are not laterally continuous (i.e. products of short periods of volcanism). The data also suggests several Mesozoic–Cenozoic plays (e.g. carbonate reefs, incised canyons). Repeatable sea surface slicks, and observable bottom-simulating reflectors and direct hydrocarbon indicators, also provide evidence of working petroleum system(s). It is hypothesised that the CVB has affinities with the Gulf of Papua with the extension of the Australian craton north of the Papuan Peninsula, with widespread deposition in the Mesozoic–Cenozoic, and with source rocks estimated to be within the hydrocarbon generative window. With incorporation of onshore data and presence of significant gravity low, it is postulated that the central and north-west were less susceptible to Late Cretaceous and Palaeocene differential uplift and erosion (related to Coral Sea breakup and extension), and thus have a higher chance of Late Mesozoic preservation.

Petroleum potential of the offshore southern Carnarvon Basin—insights from new Geoscience Australia data

2011 ◽  
Vol 51 (2) ◽  
pp. 746
Author(s):  
Irina Borissova ◽  
Gabriel Nelson
Keyword(s):  
Seismic Data ◽  
Source Rocks ◽  
Magnetic Data ◽  
Long Distance ◽  
Potential Field Data ◽  
Petroleum Potential ◽  
Gravity And Magnetic ◽  
Gravity And Magnetic Data ◽  
Insight Into ◽  
Carnarvon Basin

In 2008–9, under the Offshore Energy Security Program, Geoscience Australia (GA) acquired 650 km of seismic data, more than 3,000 km of gravity and magnetic data, and, dredge samples in the southern Carnarvon Basin. This area comprises the Paleozoic Bernier Platform and southern part of the Mesozoic Exmouth Sub-basin. The new seismic and potential field data provide a new insight into the structure and sediment thickness of the deepwater southernmost part of the Exmouth Sub-basin. Mesozoic depocentres correspond to a linear gravity low, in water depths between 1,000–2,000 m and contain between 2–3 sec (TWT) of sediments. They form a string of en-echelon northeast-southwest oriented depressions bounded by shallow-dipping faults. Seismic data indicates that these depocentres extend south to at least 24°S, where they become more shallow and overprinted by volcanics. Potential plays in this part of the Exmouth Sub-basin may include fluvio-deltaic Triassic sandstone and Lower–Middle Jurassic claystone source rocks sealed by the regional Early Cretaceous Muderong shale. On the adjoining Bernier Platform, minor oil shows in the Silurian and Devonian intervals at Pendock–1a indicate the presence of a Paleozoic petroleum system. Ordovician fluvio-deltaic sandstones sealed by the Silurian age marine shales, Devonian reef complexes and Miocene inversion anticlines are identified as potential plays. Long-distance migration may contribute to the formation of additional plays close to the boundary between the two provinces. With a range of both Mesozoic and Paleozoic plays, this under-explored region may have a significant hydrocarbon potential.

Recent exploration results in the Lower Triassic, Bedout Sub-basin: Australia's next petroleum province?

2018 ◽  
Vol 58 (2) ◽  
pp. 871 ◽  
Author(s):  
Melissa Thompson ◽  
Fred Wehr ◽  
Jack Woodward ◽  
Jon Minken ◽  
Gino D'Orazio ◽  
...  
Keyword(s):  
Oil And Gas ◽  
Lower Triassic ◽  
Effective Porosity ◽  
Petroleum System ◽  
Source Rocks ◽  
Commercial Development ◽  
North West ◽  
The North ◽  
Productive Potential ◽  
Detailed Interpretation

Commencing in 2014, Quadrant Energy and partners have undertaken an active exploration program in the Bedout Sub-basin with a 100% success rate, discovering four hydrocarbon accumulations with four wells. The primary exploration target in the basin, the Middle Triassic Lower Keraudren Formation, encompasses the reservoirs, source rocks and seals that have trapped hydrocarbons in a self-contained petroleum system. This petroleum system is older than the traditional plays on the North-West Shelf and before recent activity was very poorly understood and easily overlooked. Key reservoirs occur at burial depths of 3500–5500 m, deeper than many of the traditional plays on the North-West Shelf and exhibit variable reservoir quality. Oil and gas-condensate discovered in the first two wells, Phoenix South-1 and Roc-1, raised key questions on the preservation of effective porosity and productivity sufficient to support a commercial development. With the acquisition and detailed interpretation of 119 m of core over the Caley Member reservoir in Roc-2 and a successful drill stem test that was surface equipment constrained to 55 MMscf/d, the productive potential of this reservoir interval has been confirmed. The results of the exploration program to date, combined with acquisition of new 3D/2D seismic data, have enabled a deeper understanding of the potential of the Bedout Sub-basin. A detailed basin model has been developed and a large suite of prospects and leads are recognised across a family of hydrocarbon plays. Two key wells currently scheduled for 2018 (Phoenix South-3 and Dorado-1) will provide critical information about the scale of this opportunity.

scholarly journals Geochemical evidence for a new Triassic petroleum system on the western margin of Australia

2021 ◽  
Vol 61 (2) ◽  
pp. 616
Author(s):  
Emmanuelle Grosjean ◽  
Dianne S. Edwards ◽  
Nadege Rollet ◽  
Christopher J. Boreham ◽  
Duy Nguyen ◽  
...  
Keyword(s):  
Middle Triassic ◽  
Lower Triassic ◽  
Petroleum System ◽  
Source Rocks ◽  
Type Ii ◽  
North West ◽  
Oil Resources ◽  
Isotopic Analyses ◽  
Potential Trap ◽  
The Phoenix

The unexpected discovery of oil in Triassic sedimentary rocks of the Phoenix South 1 well on Australia’s North West Shelf (NWS) has catalysed exploration interest in pre-Jurassic plays in the region. Subsequent neighbouring wells Roc 1–2, Phoenix South 2–3 and Dorado 1–3 drilled between 2015 and 2019 penetrated gas and/or oil columns, with the Dorado field containing one of the largest oil resources found in Australia in three decades. This study aims to understand the source of the oils and gases of the greater Phoenix area, Bedout Sub-basin using a multiparameter geochemical approach. Isotopic analyses combined with biomarker data confirm that these fluids represent a new Triassic petroleum system on the NWS unrelated to the Lower Triassic Hovea Member petroleum system of the Perth Basin. The Bedout Sub-basin fluids were generated from source rocks deposited in paralic environments with mixed type II/III kerogen, with lagoonal organofacies exhibiting excellent liquids potential. The Roc 1–2 gases and the Phoenix South 1 oil are likely sourced proximally by Lower–Middle Triassic TR10–TR15 sequences. Loss of gas within the Phoenix South 1 fluid due to potential trap breach has resulted in the formation of in-place oil. These discoveries are testament to new hydrocarbon plays within the Lower–Middle Triassic succession on the NWS.

ACLAS — A method to define geologically significant lineaments from potential-field data

Geophysics ◽  
2017 ◽  
Vol 82 (4) ◽  
pp. G87-G100 ◽  
Author(s):  
Lorenzo Cascone ◽  
Chris Green ◽  
Simon Campbell ◽  
Ahmed Salem ◽  
Derek Fairhead
Keyword(s):  
Large Scale ◽  
Magnetic Data ◽  
Data Set ◽  
New Approach ◽  
Potential Field Data ◽  
North West ◽  
Gravity And Magnetic ◽  
Lineament Analysis ◽  
The Individual ◽  
Gravity And Magnetic Data

Geologic features, such as faults, dikes, and contacts appear as lineaments in gravity and magnetic data. The automated coherent lineament analysis and selection (ACLAS) method is a new approach to automatically compare and combine sets of lineaments or edges derived from two or more existing enhancement techniques applied to the same gravity or magnetic data set. ACLAS can be applied to the results of any edge-detection algorithms and overcomes discrepancies between techniques to generate a coherent set of detected lineaments, which can be more reliably incorporated into geologic interpretation. We have determined that the method increases spatial accuracy, removes artifacts not related to real edges, increases stability, and is quick to implement and execute. The direction of lower density or susceptibility can also be automatically determined, representing, for example, the downthrown side of a fault. We have evaluated ACLAS on magnetic anomalies calculated from a simple slab model and from a synthetic continental margin model with noise added to the result. The approach helps us to identify and discount artifacts of the different techniques, although the success of the combination is limited by the appropriateness of the individual techniques and their inherent assumptions. ACLAS has been applied separately to gravity and magnetic data from the Australian North West Shelf; displaying results from the two data sets together helps in the appreciation of similarities and differences between gravity and magnetic results and indicates the application of the new approach to large-scale structural mapping. Future developments could include refinement of depth estimates for ACLAS lineaments.

DISCOVERY OF SALT IN THE VULCAN GRABEN: A GEOPHYSICAL AND GEOLOGICAL EVALUATION

1991 ◽  
Vol 31 (1) ◽  
pp. 229 ◽  
Author(s):  
P.M. Smith ◽  
N.D. Sutherland
Keyword(s):  
Late Jurassic ◽  
Structural Model ◽  
Magnetic Data ◽  
Salt Diapir ◽  
Tectonic Event ◽  
North West ◽  
Cap Rock ◽  
Collapse Structures ◽  
Structural Closure ◽  
Gravity And Magnetic Data

The Paqualin-1 well in Permit AC/P2, Timor Sea, was drilled to test a large structural closure against the flank of an interpreted piercement structure located in the Late Jurassic Paqualin Graben. Prior to drilling the well interpretation of geological, seismic, gravity and magnetic data supported both a salt diapiric and/or an igneous intrusive structural model for the origin of the piercement feature. On drilling the Paqualin-1 well in December 1988, a 627 m thick evaporitic sequence was encountered in the post-rift Tertiary sequence indicating that the well had penetrated a salt overhang close to the main diapiric stock.The age of the evaporitic sequence is unclear but is considered coeval with Palaeozoic salt diapirs in the Bonaparte Basin to the east. Growth of the Paqualin diapir and a similar feature to the south, the Swan structure, which is also interpreted to be a salt diapir, appears to have been triggered initially by the Late Jurassic-Early Cretaceous breakup of the Australian north-west continental margin (doming and pillowing), and then again by a second major tectonic event in the Late Miocene associated with the collision between the Australian and Eurasian plates (diapir- ism and collapse structures).A distinctive cap rock occurs at the top of the evaporitic sequence characterised by an unusual accessory suite of primary and secondary minerals including euhedral magnetite, bipyramidal quartz, biotite, chlorite, sphene, amphibole and feldspar. The high magnetite component is considered responsible for the positive magnetic anomaly observed prior to drilling. The presence of magnetite and the other minerals in the cap rock appears to be related to the presence of exotic igneous material incorporated in the salt stock and the restricted activity of sulphate reducing bacteria in the crest of the diapir.The discovery of the Paqualin salt diapir and the interpretation of a similar structure in the adjacent Swan Graben has lead to the recognition of new play types related to the diapirs.

Sign in / Sign up

Export Citation Format

Share Document