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.

Multiphase oblique extension on the North West Shelf of Australia

2021 ◽  
Author(s):  
Chris Elders ◽  
Sara Moron
Keyword(s):  
Seismic Data ◽  
Lower Cretaceous ◽  
Passive Margin ◽  
Rift System ◽  
Active Deformation ◽  
North West ◽  
North East ◽  
The North ◽  
Northern Carnarvon Basin ◽  
Carnarvon Basin

<p>The North West Shelf of Australia has experienced numerous rift events during its prolonged evolution that most likely started in the Lower Palaeozoic and continued through to the formation of the present day passive margin in the Lower Cretaceous.  Carboniferous and Permian is associated with rifting of the Lhasa terrane, a phase extension in the Lower and Middle Jurassic associated with the separation of the Argo terrane Upper Jurassic to Lower Cretaceous extension culminated in the separation of Greater India and Australia.  Investigations based on interpretation of extensive, public domain seismic data, combined with numerical mechanical modelling, demonstrate that crustal structure, rheology and structural fabrics inherited from older events exert a significant control on the architecture of younger rifts.</p><p>Defining the older, more deeply buried rift episodes is challenging, but with seismic data that now images deeper structures more effectively, it is clear that NE-SW oriented Carboniferous to Permian aged rift structures control the overall geometry of the margin.  Variations in the timing, distribution and intensity of that rift may account for some of the complexity that governs the Triassic – a failed arm of the rift system might account for the accumulation of thick sequences of fluvio-delatic sediments in an apparent post-rift setting, while active deformation and igneous activity continued elsewhere on the margin.</p><p>A renewed phase of extension began in the latest Triassic in the western part of the Northern Carnarvon Basin, but became progressively younger to the NE.  High-resolution mechanical numerical experiments show that the dual mode of extension that characterises the Northern Carnarvon Basin, where both distributed and localised deformation occurs at the same time, is best explained by necking and boudinage of strong lower crust, inherited form the Permian rift event, proximal to the continental margin, and a subdued extensional strain rate across the distal extended margin.  A very clear and consistent pattern of ENE oriented extension, which interacts obliquely with the older NE-SW oriented Permian aged structures, is apparent across the whole of the Northern Carnarvon Basin and extends north east into the Roebuck and Browse Basins.  This is at odds with the NW-SE oriented extension predicted by the separation of the Argo terrane which occurs at this time.  This may be explained by the detached style of deformation that characterises the Mesozoic interval.  Alternatively, the separation of Greater India may have exerted a stronger influence on the evolution of the margin during the Jurassic than hitherto recognised.</p>

Controls on the preservation of Jurassic volcanism in the Northern Carnarvon Basin

2021 ◽  
Vol 61 (2) ◽  
pp. 600
Author(s):  
Michael Curtis ◽  
Simon Holford ◽  
Mark Bunch ◽  
Nick Schofield
Keyword(s):  
Early Cretaceous ◽  
Late Jurassic ◽  
Volcanic Centre ◽  
North West ◽  
The North ◽  
Igneous Provinces ◽  
Australian Continent ◽  
Northern Carnarvon Basin ◽  
Uplift And Erosion ◽  
Carnarvon Basin

The Northern Carnarvon Basin (NCB) forms part of the North West Australian margin. This ‘volcanic’ rifted margin formed as Greater India rifted from the Australian continent through the Jurassic, culminating in breakup in the Early Cretaceous. Late Jurassic to Early Cretaceous syn-rift intrusive magmatism spans 45000km2 of the western Exmouth Plateau and the Exmouth Sub-basin; however, there is little evidence of associated contemporaneous volcanic activity, with isolated late Jurassic volcanic centres present in the central Exmouth Sub-basin. The scarcity of observed volcanic centres is not typical of the extrusive components expected in such igneous provinces, where intrusive:extrusive ratios are typically 2–3:1. To address this, we have investigated the processes that led to the preservation of a volcanic centre near the Pyrenees field and the Toro Volcanic Centre (TVC). The volcanic centre near the Pyrenees field appears to have been preserved from erosion associated with the basin-wide KV unconformity by fault-related downthrow. However, the TVC, which was also affected by faulting, is located closer to the focus of regional early Cretaceous uplift along the Ningaloo Arch to the south and was partly eroded. With erosion of up to 2.6km estimated across the Ningaloo Arch, which, in places, removed all Jurassic strata, we propose that the ‘Exmouth Volcanic Province’ was originally much larger, extending south from the TVC into the southern Exmouth Sub-basin prior to regional uplift and erosion, accounting for the ‘missing’ volume of extrusive igneous material in the NCB.

CARNARVON BASIN ARCHITECTURE AND STRUCTURE DEFINED BY THE INTEGRATION OF MINERAL AND PETROLEUM EXPLORATION TOOLS AND TECHNIQUES

2002 ◽  
Vol 42 (1) ◽  
pp. 287 ◽  
Author(s):  
L.L. Pryer ◽  
K.K. Romine ◽  
T.S. Loutit ◽  
R.G. Barnes
Keyword(s):  
Seismic Data ◽  
Structural Model ◽  
Mineral Exploration ◽  
Petroleum Exploration ◽  
Block Rotation ◽  
North West ◽  
The North ◽  
Northern Carnarvon Basin ◽  
Migration Pathways ◽  
Carnarvon Basin

The Barrow and Dampier Sub-basins of the Northern Carnarvon Basin developed by repeated reactivation of long-lived basement structures during Palaeozoic and Mesozoic tectonism. Inherited basement fabric specific to the terranes and mobile belts in the region comprise northwest, northeast, and north–south-trending Archaean and Proterozoic structures. Reactivation of these structures controlled the shape of the sub-basin depocentres and basement topography, and determined the orientation and style of structures in the sediments.The Lewis Trough is localised over a reactivated NEtrending former strike-slip zone, the North West Shelf (NWS) Megashear. The inboard Dampier Sub-basin reflects the influence of the fabric of the underlying Pilbara Craton. Proterozoic mobile belts underlie the Barrow Sub-basin where basement fabric is dominated by two structural trends, NE-trending Megashear structures offset sinistrally by NS-trending Pinjarra structures.The present-day geometry and basement topography of the basins is the result of accumulated deformation produced by three main tectonic phases. Regional NESW extension in the Devonian produced sinistral strikeslip on NE-trending Megashear structures. Large Devonian-Carboniferous pull-apart basins were introduced in the Barrow Sub-basin where Megashear structures stepped to the left and are responsible for the major structural differences between the Barrow and Dampier Sub-basins. Northwest extension in the Late Carboniferous to Early Permian marks the main extensional phase with extreme crustal attenuation. The majority of the Northern Carnarvon basin sediments were deposited during this extensional basin phase and the subsequent Triassic sag phase. Jurassic extension reactivated Permian faults during renewed NW extension. A change in extension direction occurred prior to Cretaceous sea floor spreading, manifest in basement block rotation concentrated in the Tithonian. This event changed the shape and size of basin compartments and altered fluid migration pathways.The currently mapped structural trends, compartment size and shape of the Barrow and Dampier Sub-basins of the Northern Carnarvon Basin reflect the “character” of the basement beneath and surrounding each of the subbasins.Basement character is defined by the composition, lithology, structure, grain, fabric, rheology and regolith of each basement terrane beneath or surrounding the target basins. Basement character can be discriminated and mapped with mineral exploration methods that use non-seismic data such as gravity, magnetics and bathymetry, and then calibrated with available seismic and well datasets. A range of remote sensing and geophysical datasets were systematically calibrated, integrated and interpreted starting at a scale of about 1:1.5 million (covering much of Western Australia) and progressing to scales of about 1:250,000 in the sub-basins. The interpretation produced a new view of the basement geology of the region and its influence on basin architecture and fill history. The bottom-up or basement-first interpretation process complements the more traditional top-down seismic and well-driven exploration methods, providing a consistent map-based regional structural model that constrains structural interpretation of seismic data.The combination of non-seismic and seismic data provides a powerful tool for mapping basement architecture (SEEBASE™: Structurally Enhanced view of Economic Basement); basement-involved faults (trap type and size); intra-sedimentary geology (igneous bodies, basement-detached faults, basin floor fans); primary fluid focussing and migration pathways and paleo-river drainage patterns, sediment composition and lithology.

THE NORTH WEST SHELF

1989 ◽  
Vol 29 (1) ◽  
pp. 529 ◽  
Author(s):  
A.E. Cockbain
Keyword(s):  
Oil Fields ◽  
Gas Field ◽  
North West ◽  
Canning Basin ◽  
The North ◽  
The Indian Ocean ◽  
Northern Carnarvon Basin ◽  
Siliciclastic Sediments ◽  
Breakup Unconformity ◽  
Carnarvon Basin

The region of the North West Shelf dealt with in this paper is underlain by three of the four basins which make up the Westralian Superbasin. The Bonaparte Basin lies outside the scope of this paper; the other basins are the Browse Basin, the offshore Canning Basin, here named the Western Canning Basin, and the offshore Carnarvon Basin, here called the Northern Carnarvon Basin. Sediments belonging to ten depositional sequences (Pz5, Mzl to Mz5, and Czl to Cz4) are present in the basins, the oldest being of Late Carboniferous and Permian age (Pz5).Deposition commenced in rift (interior fracture) basins under fluvial/deltaic conditions in the Late Permian/Early Triassic (Mzl), when the North West Shelf was part of Gondwana. Continental breakup took place in the Middle Jurassic (breakup unconformity between Mz2 and Mz3), and marine conditions prevailed over the Westralian Superbasin thereafter, with deposition taking place in a marginal sag setting. Siliciclastic sediments gave place to carbonates in the Late Cretaceous (Mz5) as the Indian Ocean grew larger.Parts of the area have been under permit since 1946, and to date some 227 exploration wells have been drilled. The most intensive exploration has taken place in the Northern Carnarvon Basin (191 wells), followed by the Browse Basin (20 wells), and Western Canning Basin (16 wells). Thirty- four economic and potentially economic discoveries have been made. The main target reservoirs are Triassic, Jurassic and Cretaceous, and the regional seals are Triassic and Cretaceous. The fields are of two types: pre- breakup unconformity (mainly tilted horst blocks), and post- breakup unconformity (usually four- way dip closures). Of the five producing fields, the North Rankin Gas Field is a pre- breakup field, while the four oil fields (Barrow, Harriet, South Pepper and North Herald) are all post- breakup.

Integration of new interpretation, attribute analysis and inversion results for the Dampier Sub-basin, North West Shelf of Australia

2021 ◽  
Vol 61 (2) ◽  
pp. 611
Author(s):  
Jarrad Grahame ◽  
Jianfeng Yao
Keyword(s):  
Oil And Gas ◽  
New Ventures ◽  
Large Area ◽  
North West ◽  
The North ◽  
Avo Inversion ◽  
Attribute Analysis ◽  
New Interpretation ◽  
Northern Carnarvon Basin ◽  
Carnarvon Basin

The Davros-Typhon Multi-Client 3D surveys are located approximately 70km from the north-west coast of Australia, largely covering the NE trending Dampier Sub-basin and straddling the Rankin Trend within the Northern Carnarvon Basin. The basins within the North West Shelf formed as a result of seafloor spreading, associated with the breakup of the North West margin of East Gondwana. The combined, contiguous Davros-Typhon survey areas cover a number of significant discoveries and producing fields, which include both oil and gas accumulations. The key objective of the survey was to enhance the imaging of Triassic to Lower Cretaceous reservoir units and to develop a new interpretation framework, made possible by the modern broadband acquisition parameters and advanced processing techniques. Challenges associated with imaging and interpretation include the effects of high velocity carbonate overburden, steeply dipping structures, fault shadow and structural complexity at depth, which is critical for evaluation of reservoir targets. A major reprocessing effort was undertaken to further mitigate these issues, which included Davros and a number of adjacent existing 3D surveys, resulting in the Typhon Multi-Client 3D. CGG Multi-client and New Ventures geoscientists, in collaboration with CGG Seismic Imaging, have undertaken new interpretation and amplitude versus offset (AVO) inversion analysis using subsets of the Typhon 3D. The resulting volume-based attribute analysis and integration of new AVO inversion results demonstrates enhanced attribute quality for the reprocessed data and provides a platform for quantitative analysis over a large area of the Northern Carnarvon Basin.

MULTIPLE REMOVAL SUCCESS IN THE CARNARVON BASIN WITH SRME

2005 ◽  
Vol 45 (1) ◽  
pp. 399
Author(s):  
A. Long ◽  
P. Zhao ◽  
P. Gatley ◽  
D. Cooke ◽  
R. van Borselen ◽  
...  
Keyword(s):  
Data Quality ◽  
Three Dimensional ◽  
Small Component ◽  
North West ◽  
The North ◽  
Time Migration ◽  
Short Period ◽  
Northern Carnarvon Basin ◽  
Data Location ◽  
Carnarvon Basin

In 2003, Santos Ltd revisited a poor data quality area in the northern Carnarvon Basin, offshore Western Australia, where both short and long period multiple energy prohibits imaging of the underlying geology. Previous reprocessing efforts had failed to satisfactorily improve data quality, or reduce the level of multiple contamination. A two-dimensional (2D) reprocessing project was initiated to establish whether any modern variant of Surface-Related Multiple Elimination (SRME) could have success. Consequently, several versions of SRME were tested, with all output diagnostics being imaged with anisotropic Kirchhoff pre-stack time migration (PSTM). The new SRME results are a significant improvement over previous reprocessing efforts, and provide a much better platform for the picking of anisotropic velocity functions, and the application of PSTM imaging. Most of the multiple energy in this location is actually surface-related, with only a small component of internal multiple reverberations. Both long and short period multiple energy was successfully removed, and interpretation can now be pursued with more confidence in a difficult data location. Many outof- the-plane events still appear to contaminate the final 2D result, so a full three-dimensional (3D) production project was then pursued using standard (2D) SRME processing applied to 3D data gathers.Despite many noise challenges existing within the 3D field data, the final data images shed new light on a challenging geological environment, and prove the merits of SRME processing. A new generation of 3D acquisition and processing technology is now required to improve upon existing results, so a brief consideration is also given to the potential applications of 3D SRME processing to 3D seismic data from the North West Shelf. A brief example from offshore Brazil is used to illustrate the potential benefits of 3D SRME.

Assessing shale mineral composition: From lab to seismic scale

2019 ◽  
Vol 38 (5) ◽  
pp. 385-391
Author(s):  
Roman Beloborodov ◽  
Marina Pervukhina ◽  
Matthew Josh ◽  
Michael B. Clennell ◽  
Juerg Hauser
Keyword(s):  
Mineralogical Composition ◽  
Hydrocarbon Exploration ◽  
Seismic Survey ◽  
North West ◽  
The North ◽  
Exploration And Production ◽  
Northern Carnarvon Basin ◽  
Inclined Boreholes ◽  
Hydrocarbon Exploration And Production ◽  
Carnarvon Basin

Shales have always been a difficult target for drilling of deviated and horizontal wells. In the presence of azimuthal stress fields, inclined boreholes in smectite-rich shales exhibit geomechanical instabilities and can result in borehole failure. The complex geology of the major gas fields in the Northern Carnarvon Basin on the North West Shelf of Australia makes it necessary to drill deviated wells through the smectite-rich shale seal extending more than 1 km in thickness. Predicting the mineralogical composition of shales in the area is therefore crucial for the success of drilling operations related to hydrocarbon exploration and production. Here we introduce a novel workflow that combines seismic data, well logs, and laboratory measurements to rapidly infer smectite content in shale. The workflow is applied to the Duyfken 3D seismic survey in the central part of the Northern Carnarvon Basin. The results of our quantitative interpretation are verified against the laboratory X-ray diffraction measurements from the test well that was not used for interpretation, and they match the test data well within the determined uncertainty bounds.

scholarly journals A revised lithostratigraphy for the Palaeogene – lower Neogene of the Danish North Sea

2005 ◽  
Vol 7 ◽  
pp. 21-24
Author(s):  
Poul Schiøler ◽  
Jan Andsbjerg ◽  
Ole R. Clausen ◽  
Gregers Dam ◽  
Karen Dybkjær ◽  
...  
Keyword(s):  
North Sea ◽  
Energy Agency ◽  
Sequence Stratigraphic ◽  
Oil Companies ◽  
The North ◽  
Reference Sections ◽  
Stratigraphic Model ◽  
Lithostratigraphic Units ◽  
The North Sea ◽  
Stratigraphic Nomenclature

Intense drilling activity following the discovery of the Siri Field in 1995 has resulted in an improved understanding of the siliciclastic Palaeogene succession in the Danish North Sea sector (Fig. 1). Many of the new wells were drilled in the search for oil reservoirs in sand bodies of Paleocene–Eocene age. The existing lithostratigraphy was based on data from a generation of wells that were drilled with deeper stratigraphic targets, with little or no interest in the overlying Palaeogene sediments, and thus did not adequately consider the significance of the Palaeogene sandstone units in the Danish sector. In order to improve the understanding of the distribution, morphology and age of the Palaeogene sediments, in particular the economically important sandstone bodies, a detailed study of this succession in the Danish North Sea has recently been undertaken. An important aim of the project was to update the lithostratigraphic framework on the basis of the new data.The project was carried out at the Geological Survey of Denmark and Greenland (GEUS) with participants from the University of Aarhus, DONG E&P and Statoil Norway, and was supported by the Danish Energy Agency. Most scientific results cannot be released until September 2006, but a revised lithostratigraphic scheme may be published prior to that date. Formal definition of new units and revision of the lithostratigraphy are in preparation. All of the widespread Palaeogene mudstone units in the North Sea have previously been formally established in Norwegian or British wells, and no reference sections exist in the Danish sector. As the lithology of a stratigraphic unit may vary slightly from one area to another, Danish reference wells have been identified during the present project, and the lithological descriptions of the formations have been expanded to include the appearance of the units in the Danish sector. Many of the sandstone bodies recently discovered in the Danish sector have a limited spatial distribution and were sourced from other areas than their contemporaneous counterparts in the Norwegian and British sectors. These sandstone bodies are therefore defined as new lithostratigraphic units in the Danish sector, and are assigned Danish type and reference sections. There is a high degree of lithological similarity between the Palaeogene–Neogene mudstone succession from Danish offshore boreholes and that from onshore exposures and boreholes, and some of the mudstone units indeed seem identical. However, in order to acknowledge the traditional distinction between offshore and onshore stratigraphic nomenclature, the two sets of nomenclature are kept separate herein. In recent years oil companies operating in the North Sea have developed various in-house lithostratigraphic charts for the Paleocene–Eocene sand and mudstone successions in the Danish and Norwegian sectors. A number of informal lithostratigraphic units have been adopted and widely used. In the present project, these units have been formally defined and described, maintaining their original names whenever feasible, with the aim of providing an unequivocal nomenclature for the Palaeogene – lower Neogene succession in the Danish sector. It has not been the intention to establish a sequence stratigraphic model for this succession in the North Sea; the reader is referred to the comprehensive works of Michelsen (1993), Neal et al. (1994), Mudge & Bujak (1994, 1996a, b), Michelsen et al. (1995, 1998), Danielsen et al. (1997) and Rasmussen (2004).

THE HYDROCARBON POTENTIAL OF EXPLORATION PERMITS WA-299-P AND WA-300-P, CARNARVON BASIN: A CASE STUDY

2003 ◽  
Vol 43 (1) ◽  
pp. 339 ◽  
Author(s):  
M. Partington ◽  
K. Aurisch ◽  
W. Clark ◽  
I. Newlands ◽  
S. Phelps ◽  
...  
Keyword(s):  
Late Cretaceous ◽  
Hydrocarbon Potential ◽  
North West ◽  
The North ◽  
Alluvial Channel ◽  
Main Fault ◽  
Early Palaeozoic ◽  
Eastern Edge ◽  
Carnarvon Basin

Exploration permits WA-299-P and WA-300-P lie west of the North West Cape in a frontier part of the Carnarvon Basin where the largely Mesozoic Exmouth Sub-basin abuts against shallow Palaeozoic strata of the Gascoyne Platform. The only exploration well, within the permits, Pendock–1, penetrated a thin Valanginian Birdrong Sandstone unconformably overlying Carboniferous to Silurian units, so the Mesozoic hydrocarbon potential of the area is effectively untested.The structure of the area comprises a complex mosaic of NNE–SSW trending Early Palaeozoic extensional, listric growth faults, dissected by NW–SE trending Permian extension relay zones. Subsequent phases of Callovian– Oxfordian and Valanginian uplift, together with Late Cretaceous and Miocene inversion along the main fault zone, further complicate the structure. Several seismic events, some of which correlate with magnetic anomalies, are discordant with the local stratigraphy indicating a probable igneous origin.The primary targets are the Birdrong Sandstone and underlying Wogatti Formation, both of which host onshore oil accumulations at Rough Range and Parrot Hill–1. The retrogradational clastic shoreline facies of the Birdrong Sandstone is well known along the eastern edge of the Dampier–Barrow–Exmouth Sub-basins. The Wogatti Formation was deposited as a more restricted alluvial/ fluvial sheet sand facies, so far identified only in the onshore Cape Range area. Where the Jurassic is preserved, fluvial/alluvial channel sand facies of the Middle Jurassic Learmonth Formation, known onshore at Sandy Point–1, and Callovian nearshore sands, as observed in Unknown Hill–l, are expected to be important secondary targets.The most promising play types within the Southern Carnarvon Basin are dip and fault-dip closures at Birdrong/Wogatti level associated with Late Cretaceous reactivation of the main NE–SW listric faults, and accentuated by later Miocene compression. The most significant exploration risks are charge and the high risk of biodegradation of reservoired liquid hydrocarbons (critically linked to reservoir temperature).

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