The Roebuck Basin, Beagle and Barcoo Sub-basin well folio

2019 ◽  
Vol 59 (2) ◽  
pp. 920 ◽  
Author(s):  
Duy Nguyen ◽  
Nadege Rollet ◽  
Emmanuelle Grosjean ◽  
Dianne S. Edwards ◽  
Steve Abbott ◽  
...  
Keyword(s):  
Lower Cretaceous ◽  
Geochemical Data ◽  
Well Log ◽  
North West ◽  
Sequence Stratigraphic ◽  
Seal Integrity ◽  
Critical Issues ◽  
Secondary Objective ◽  
And Migration ◽  
Migration Pathways

The Roebuck Basin and the adjoining Beagle and Barcoo sub-basins are underexplored areas on Australia’s North West Shelf that are undergoing renewed exploration interest since the discovery of oil at Phoenix South 1 in 2014 and subsequent hydrocarbon discoveries in the Bedout Sub-basin. A well folio of 24 offshore wells across the Beagle, Bedout, Rowley and Barcoo sub-basins has been compiled as part of Geoscience Australia’s hydrocarbon prospectivity assessment across the region. It consists of composite well log plots and well correlations that summarise lithology, lithostratigraphy, Geoscience Australia’s newly acquired biostratigraphic and geochemical data as well as results of petrophysical analysis. A revised sequence-stratigraphic interpretation, key petroleum system elements and drilling results are also documented. The wells dominantly target Triassic shoreward facies (Keraudren Formation) as the primary reservoir objective and Jurassic fluvial-deltaic (Depuch Formation) and/or Lower Cretaceous sandy deltaic facies as the secondary objective. The Keraudren Formation sandstones are sealed intra-formationally either by discontinuous units and/or by the regional Cossigny Member. The Jurassic Depuch Formation sandstones are sealed by regional Lower Cretaceous mudstones. Both charge and structure have been identified as critical issues in the Roebuck Basin. In the Beagle Sub-basin, seal integrity and migration pathways are also considered high risk. Well correlations have identified differences in the basin history and provide insights into the distribution of facies and other characteristics of the Jurassic and Triassic successions.

SEAL POTENTIAL IN CRETACEOUS AND LATE JURASSIC ROCKS OF THE VULCAN SUB-BASIN, NORTH WEST SHELF AUSTRALIA

2002 ◽  
Vol 42 (1) ◽  
pp. 203 ◽  
Author(s):  
T. Kivior ◽  
J.G. Kaldi ◽  
S.C. Lang
Keyword(s):  
Data Quality ◽  
Late Jurassic ◽  
Column Height ◽  
Areal Extent ◽  
North West ◽  
Sequence Stratigraphic ◽  
Seal Integrity ◽  
Almost All ◽  
Rock Mechanical Properties ◽  
Mercury Injection Capillary Pressure

The occurrence of palaeo-oil columns in Late Jurassic and Cretaceous reservoirs in the Vulcan Sub-basin suggests that hydrocarbon accumulations have leaked. It is unclear whether accumulations have leaked through breach of top seal or fault seal. This paper evaluates the top seal potential for hydrocarbon accumulations in the Vulcan Sub-basin. Seal potential (SP) combines seal capacity (the hydrocarbon column height that can physically be held back by a seal), seal geometry (the areal extent and thickness of the seal) and seal integrity (rock mechanical properties of the seal). Seal capacities are measured using mercury injection capillary pressure calculations. Areal extent is evaluated using sedimentological and sequence stratigraphic principles. Thickness is determined empirically from well logs and seismic data. Seal integrity is derived from a brittleness index. In addition, a component relating to data quality and quantity is included in seal potential evaluation.Lower Vulcan Formation SP ranges from low to high due to variations in seal capacity and thickness risks as well as data quality and quantity. High SP occurs in the main depocentres and low SP occurs on palaeo-highs and basin margins. Upper Vulcan Formation SP ranges from low to moderate due to variations in seal capacity and data issues. Moderate SP occurs in depocentres and low SP on basin margins. In the Echuca Shoals Formation seal capacity, seal extent and integrity as well as data quality and quantity are good. Seal thickness, however, is inconsistent, resulting in SP variations from good to poor as a function of thickness. Jamieson Formation has high seal capacities, is thick and areally extensive. The seal potential, however, is locally moderate (e.g. on the Ashmore Platform) due to integrity issues. Woolaston, Gibson and Fenelon (WGF) Formations are grouped together as the regional seal and in this group SP varies from low to high. The WGF rocks have high seal capacities, are areally extensive and thick and the data quality and quantity is good. The main risk is integrity, which increases from northwest to southeast in the basin.Based on the overall seal potential analyses, almost all seals in the area are capable of holding back hydrocarbon columns greater than present or paleocolumns encountered. This suggests that hydrocarbon leakage in the Vulcan Sub-basin was unlikely to have occurred as a result of top seal capillary failure.

HYDRODYNAMIC ANALYSIS OF FLOW SYSTEMS AND FAULT SEAL INTEGRITY IN THE NORTH WEST SHELF OF AUSTRALIA

2001 ◽  
Vol 41 (1) ◽  
pp. 347 ◽  
Author(s):  
C.J. Otto ◽  
J.R. Underschultz ◽  
A.L. Hennig ◽  
V.J. Roy
Keyword(s):  
Fluid Flow ◽  
Regional Scale ◽  
Local Flow ◽  
Hydrodynamic Analysis ◽  
North West ◽  
Seal Integrity ◽  
The North ◽  
Regional Flow ◽  
Aquifer Systems ◽  
Migration Pathways

The North West Shelf hydrodynamics pressure database, developed as part of the North West Shelf Hydrodynamics Project, currently contains 7,780 pressure data points and hundreds of stress, temperature and water salinity data. All data have been ranked using a newly developed quality-control system. Equivalent hydraulic head mapping (fluid potential energy analysis) to interpret fluid migration pathways, hydraulic barriers and conduits was shown to be a valid technique despite lateral and vertical fluid density variations. Pressureelevation analysis identified six major aquifer systems (hydrostratigraphic units) in the regional North West Shelf. On a regional scale, the general flow direction in the North West Shelf is from the basins’ depocentres towards the onshore and upwards to the shallower aquifer systems. Compaction-driven flow is the main driving force for fluid flow in the North West Shelf. Overpressured compartments in the Carnarvon Basin are leaking, not hydraulically isolated from the regional flow field, thus generating their own local flow system. In general, fluid flow within the hydrostratigraphic units is parallel to the trend of major fault systems, which act as barriers in the horizontal plane of the aquifer. However, local-scale hydrodynamic analysis has shown that faults can act as fluid conduits between hydrostratigraphic units providing vertical hydraulic communication (e.g. Mardie to Barrow aquifers). Case studies in the Harriet, Gorgon, Griffin, Goodwyn and Vulcan areas have shown that the migration paths can be very complex due to the hydraulic nature of the faults and the presence of overpressured compartments

RECENT ADVANCES IN THE SEQUENCE STRATIGRAPHY OF THE TRIASSIC TO LOWER CRETACEOUS SUCCESSION IN THE NORTHERN CARNARVON BASIN, AUSTRALIA

1997 ◽  
Vol 37 (1) ◽  
pp. 429 ◽  
Author(s):  
D. Jablonski
Keyword(s):  
Sequence Stratigraphy ◽  
Lower Cretaceous ◽  
Coarse Grained ◽  
North West ◽  
Sequence Stratigraphic ◽  
The North ◽  
Invaluable Tool ◽  
Northern Carnarvon Basin ◽  
Stratigraphic Nomenclature ◽  
Carnarvon Basin

Application of sequence stratigraphy to well and seismic data has resulted in major revisions to the stratigraphic subdivision and understanding of the hydrocarbon system in the Northern Carnarvon Basin of Australia.A sequence stratigraphic nomenclature which integrates the biostratigraphic control and sequence terminology has been developed. This has proven to be an invaluable tool in enabling effective communication between geologists, biostratigraphers, and seismic interpreters. This nomenclature reduces the need to refer to absolute time scales and Epoch or Stage names, all of which are subject to change. The revised subdivision and new terminology can be used to reliably correlate across wide areas on the North West Shelf and possibly beyond.Six first and second order megasequences are recognised within the Triassic to Lower Cretaceous succession. These megasequences are mostly bounded by transgressive surfaces that are expressed on well logs as abrupt facies changes and on seismic as major downlap surfaces, indicating significant acceleration in subsidence rates and an increase in accommodation space in the basin. Each megasequence consists of an initial transgressive section of mainly fine-grained clastics overlain by a regressive and usually extensive succession of coarse-grained deposits. Recognition of the significance of these megasequence boundaries, and the stages of extension, has resulted in a vastly improved understanding of surfaces, some of which have previously been mis-interpreted as 'break-up unconformities'. Two distinct stratigraphic events, a Callovian transgression and an Oxfordian Iowstand, have been recognised as separate megasequence boundaries, which has a significant impact on the prospectivity of the Northern Carnarvon Basin.

scholarly journals Invasive Plant Species Distribution Is Structured by Soil and Habitat Type in the City Landscape

Plants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 773
Author(s):  
Ilona Szumańska ◽  
Sandra Lubińska-Mielińska ◽  
Dariusz Kamiński ◽  
Lucjan Rutkowski ◽  
Andrzej Nienartowicz ◽  
...  
Keyword(s):  
Distribution Pattern ◽  
Species Distribution ◽  
Human Activities ◽  
Invasive Plant ◽  
Habitat Type ◽  
Permanent Plots ◽  
Human Land Use ◽  
And Migration ◽  
Migration Pathways ◽  
The City

Invasive alien species (IAS) is a global problem that largely relates to human activities and human settlements. To prevent the further spread of IAS, we first need to know their pattern of distribution, to determine which constitutes the greatest threat, and understand which habitats and migration pathways they prefer. Our research aimed to identify the main vectors and distribution pattern of IAS of plants in the city environment. We checked the relations between species distribution and such environmental factors as urban soil type and habitat type. We applied data on IAS occurrence (collected in the period 1973–2015) in 515 permanent plots with dimensions of 0.5 × 0.5 km and analyzed by direct ordination methods. In total, we recorded 66 IAS. We found a 27% variance in the IAS distribution pattern, which can be explained by statistically significant soil and habitat types. The most important for species distribution were: river and alluvial soils, forests and related rusty soils, and places of intensive human activities, including areas of urbisols and industriosols. Our results provide details that can inform local efforts for the management and control of invasive species, and they provide evidence of the different associations between natural patterns and human land use.

scholarly journals Ab Initio Investigation of Helium Mobility in La2Zr2O7 Pyrochlore

Crystals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 667
Author(s):  
Yanxia Lu ◽  
Qing Peng ◽  
Chenguang Liu
Keyword(s):  
Nuclear Waste ◽  
Density Functional ◽  
Minimum Energy ◽  
Elastic Band ◽  
Waste Forms ◽  
Band Method ◽  
And Migration ◽  
High Level ◽  
Migration Pathways ◽  
Nuclear Waste Forms

The α-decay of incorporated actinides continuously produces helium, resulting in helium accumulation and causing security concerns for nuclear waste forms. The helium mobility is a key issue affecting the accumulation and kinetics of helium. The energy barriers and migration pathways of helium in a potential high-level nuclear waste forms, La2Zr2O7 pyrochlore, have been investigated in this work using the climbing image nudged elastic band method with density functional theory. The minimum energy pathway for helium to migrate in La2Zr2O7 is identified as via La–La interstitial sites with a barrier of 0.46 eV. This work may offer a theoretical foundation for further prospective studies of nuclear waste forms.

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