Geology and petroleum prospectivity of the deepwater Otway and Sorell basins: new insights from an integrated regional study

2011 ◽  
Vol 51 (2) ◽  
pp. 692 ◽  
Author(s):  
Andrew Stacey ◽  
Cameron Mitchell ◽  
Goutam Nayak ◽  
Heike Struckmeyer ◽  
Michael Morse ◽  
...  
Keyword(s):  
Continental Margin ◽  
Regional Scale ◽  
Rift System ◽  
Aeromagnetic Data ◽  
Regional Study ◽  
Sequence Stratigraphic ◽  
Petroleum Systems ◽  
Tectonic History ◽  
Complex Structural ◽  
Potential Field Modelling

The frontier deepwater Otway and Sorell basins lie offshore of southwestern Victoria and western Tasmania at the eastern end of Australia’s Southern Rift System. The basins developed during rifting and continental separation between Australia and Antarctica from the Cretaceous to Cenozoic. The complex structural and depositional history of the basins reflects their location in the transition from an orthogonal–obliquely rifted continental margin (western–central Otway Basin) to a transform continental margin (southern Sorell Basin). Despite good 2D seismic data coverage, these basins remain relatively untested and their prospectivity poorly understood. The deepwater (> 500 m) section of the Otway Basin has been tested by two wells, of which Somerset–1 recorded minor gas shows. Three wells have been drilled in the Sorell Basin, where minor oil shows were recorded near the base of Cape Sorell–1. As part of the federal government-funded Offshore Energy Security Program, Geoscience Australia has acquired new aeromagnetic data and used open file seismic datasets to carry out an integrated regional study of the deepwater Otway and Sorell basins. Structural interpretation of the new aeromagnetic data and potential field modelling provide new insights into the basement architecture and tectonic history, and highlights the role of pre-existing structural fabric in controlling the evolution of the basins. Regional scale mapping of key sequence stratigraphic surfaces across the basins, integration of the regional structural analysis, and petroleum systems modelling have resulted in a clearer understanding of the tectonostratigraphic evolution and petroleum prospectivity of this complex basin system.

Resolving lithostratigraphic complexities in the Crayfish Group, Otway Basin using chemostratigraphy

2021 ◽  
Vol 61 (2) ◽  
pp. 588
Author(s):  
Betina Bendall ◽  
Anne Forbes ◽  
Tony Hill
Keyword(s):  
Continental Margin ◽  
Structural Complexity ◽  
Significant Part ◽  
Rift System ◽  
Lacustrine Environment ◽  
Hydrocarbon Production ◽  
Inorganic Geochemistry ◽  
System A ◽  
Structural Relationships ◽  
Complex Structural

The Otway Basin comprises a significant part of the eastern Australian Southern Rift System, a divergent passive continental margin formed during the Cretaceous separation of the Australian and Antarctic continents. Early rifting activity resulted in the development of many half grabens within the Otway Basin, which are largely infilled by sediments of the Casterton Formation and Crayfish Group. Despite over 20 years of exploration and hydrocarbon production from these units however, their lithostratigraphic characterisation and nomenclature remain ambiguous, with structural complexity and prevalent lateral facies changes leading to confusion in their basin-wide correlation. Deposited in a largely non-marine, fluvial/lacustrine environment, repeating cycles of sandstones and shales of the Crayfish Group can be difficult to resolve using petrology, palynology and wireline log data. The use of chemostratigraphy is favoured as an investigative tool in this situation since changes in provenance, lithic composition, facies, weathering and diagenesis are reflected in the mineralogy of the sediments, resulting in variations in their inorganic geochemistry. Uniform sedimentary successions can thus potentially be differentiated into unique sequences and packages based on their characteristic geochemistry, aiding in the resolution of complex structural relationships and facies changes. In this study, we present new inorganic geochemistry data for four key wells in the South Australian (SA) Penola Trough and interpret the geochemistry data consistent with, and building on, the chemostratigraphic schema of Forbes et al. to demonstrate its utility and robustness. We then undertake inter-well wireline log correlations across the SA Penola Trough using the wells with chemostratigraphic data as controls.

The Role of GIS in the Interdisciplinary Investigations at Olorgesailie, Kenya, a Pleistocene Archaeological Locality

1996 ◽  
Author(s):  
Richard Potts ◽  
Daniel Cole
Keyword(s):  
Spatial Databases ◽  
Regional Scale ◽  
Interdisciplinary Studies ◽  
Rift System ◽  
East African Rift System ◽  
Early Hominid ◽  
Gis Applications ◽  
Basement Rocks ◽  
Complex Structural ◽  
African Rift

A geographic information system is an ideal tool for use in interdisciplinary studies because it provides automated means of linking and relating different spatial databases. In this paper we discuss GIS applications to ongoing archaeological and paleoecological studies at Olorgesailie, an early hominid archaeological locality in the rift valley of southern Kenya and one of the most noted Acheulian handaxe sites worldwide (Isaac 1977). The questions being asked in early hominid archaeology require thinking beyond individual artifacts and site excavations to broader spatial scales within welldefined time intervals (or chronostratigraphic units) (Blumenschine and Masao 1991; Potts 1991). The sedimentary exposures at Olorgesailie permit the smallest spatial scale of individual artifacts and fossils to be integrated with regional-scale studies. Since many of the GIS applications are still in initial form, the purpose here is largely to illustrate the conceptual framework by which GIS integrates the analysis of spatial data at varying geographic scales in the Olorgesailie basin. Covering over 4000 km in length, the African Rift System trends southward from the Afar Triangle in the Red Sea region to south of the Zambezi River in Zambia. The numerous continental rift basins that make up the rift system have a complex structural and volcanic history. For most of its length, the African Rift traverses Ethiopia, Kenya, and Tanzania. The rift is divisible into eastern and western portions, which merge into a broad faulted region in northern Tanzania (Baker et al. 1972). Between the eastern and western rifts, occupying portions of Uganda, Tanzania, and northern Kenya, is an uplifted plateau 1000 to 1200 m in elevation. Uplifted, elongated domal structures located in Ethiopia and Kenya form the structural base from which the East African Rift System has developed. The rocks that make up this shield complex are Precambrian gneisses, quartzites, and schists. In addition to intrusions by dikes and plutons, these basement rocks have been altered by partial melting and metamorphism. Significant though episodic uplift of the Kenyan dome and its flanks during the late Cretaceous and middle and late Tertiary contributed to the development of a graben structure (Baker 1986; Baker et al. 1972).

A quantitative approach to regional screening of petroleum systems, Westralian Superbasin

2015 ◽  
Vol 55 (2) ◽  
pp. 401
Author(s):  
Christopher Paschke ◽  
Rob K. Sawyer ◽  
Catherine Belgarde ◽  
Chris Yarborough ◽  
Christina Huenink
Keyword(s):  
Source Rock ◽  
Systems Analysis ◽  
Regional Scale ◽  
Source Rocks ◽  
Regional Study ◽  
Seismic Line ◽  
Petroleum Systems ◽  
Reflection Seismic ◽  
Stratigraphic Position

The greater Westralian Superbasin comprises multiple petroleum systems ranging in age from the Early Paleozoic to the Paleogene (Bradshaw et al, 1994). A subset of these systems is typified by marine incursions with a deposition of liquids-prone source rocks. Variability in Westralian sediment fill and source rock stratigraphic position can be demonstrated on a continuous mega-regional 2D deep reflection seismic line that extends from Carnarvon through Browse and into the Bonaparte Basin. Beginning in 2013, BHP Billiton initiated a comprehensive regional study of the Westralian margin to better risk existing and new play fairways. From this work, a hydrocarbon systems analysis from the Dampier Sub-basin and its application for exploration as a regional analogue is described. From a compilation of both open-file and proprietary data, a subset of Dampier well penetrations was chosen, based on the quality of available source rock data. 1D models were constructed and thermally calibrated to BHP Billiton’s recent re-interpretation of the sub-regional crustal architecture. The ultimate expelled petroleum (UEP) was calculated at each well and then extrapolated regionally to determine the total basin hydrocarbon potential. Maturity of the source rock is described using the state of thermal stress (STS) parameter (Pepper and Corvi, 1995). Compared with more data- and labour-intensive 3D basin modelling, integration of 1D basin models, UEP and STS parameters allow for a rapid quantitative and regional-scale basin analysis. Using this workflow in data-constrained basins like the Dampier Sub-basin serves as an important analogue for assessing and risking petroleum systems in both of the established and frontier portions of the Australian margin.

Age, evolution and tectonic history of the Highland Border Complex, Scotland

1984 ◽  
Vol 75 (2) ◽  
pp. 113-133 ◽  
Author(s):  
Gordon B. Curry ◽  
B. J. Bluck ◽  
C. J. Burton ◽  
J. K. Ingham ◽  
David J. Siveter ◽  
...  
Keyword(s):  
Regional Scale ◽  
Plate Boundary ◽  
North American Plate ◽  
Tectonic History ◽  
Lower Ordovician ◽  
Northwestern Margin ◽  
Comprehensive Survey ◽  
History Of ◽  
Early Palaeozoic ◽  
Western Ireland

I. ABSTRACT: Research interest in the Highland Border Complex has been pursued sporadically during the past 150 years. The results and conclusions have emphasised the problems of dealing with a lithologically disparate association which crops out in isolated, fault-bounded slivers along the line of the Highland Boundary fault. For much of the present century, the debate has centred on whether the rocks of the complex have affinities with the Dalradian Supergroup to the N, or are a discrete group. Recent fossil discoveries in a wide variety of Highland Border rocks have confirmed that many are of Ordovician age, and hence cannot have been involved in at least the early Grampian deformational events (now accurately dated as pre-Ordovician) which affect the Dalradian Supergroup. Such palaeontological discoveries form the basis for a viable biostratigraphical synthesis. On a regional scale, it is apparent that the geological history of the Highland Border rocks must be viewed in the context of plate boundary tectonism along the entire northwestern margin of Iapetus during Palaeozoic times.II. ABSTRACT: Silicified articulate brachiopods from the Lower Ordovician (Arenig) Dounans Limestone are extremely rare but the stratigraphically diagnostic generaArchaeorthisSchuchert and Cooper, andOrthidiumHall and Clarke, have been identified. In addition, three specimens with characteristic syntrophiid morphology have been recovered. Inarticulate brachiopods are known from Stonehaven and Bofrishlie Burn near Aberfoyle, and have also been previously recorded from Arran.III. ABSTRACT: Micropalaeontological investigation of the Highland Border Complex has produced a range of microfossils including chitinozoans, coleolids, calcispheres and other more enigmatic objects. The stratigraphical ranges of the species lie almost entirely within the Ordovician and reveal a scatter of ages for different lithologies from the Arenig through to the Caradoc or Ashgill, with a pronounced erosional break between the Llandeilo and the Caradoc.IV. ABSTRACT: A Lower Ordovician (Arenig Series) silicified ostracode fauna from the Highland Border Dounans Limestone at Lime Craig Quarry, Aberfoyle, Central Scotland, represents the earliest record of this group of Crustacea from the British part of the early Palaeozoic ‘North American’ plate.V. ABSTRACT: Palaeontological age determinations for a variety of Highland Border rocks are presented. The data are based on the results of recent prospecting which has demonstrated that macro- and microfossils are present in a much greater range of Highland Border lithologies than previously realised. Data from other studies are also incorporated, as are modern taxonomie re-assessments of older palaeontological discoveries, in a comprehensive survey of Highland Border biostratigraphy. These accumulated data demonstrate that all fossiliferous Highland Border rocks so far discovered are of Ordovician age, with the exception of the Lower Cambrian Leny Limestone.VI. ABSTRACT: The Highland Border Complex consists of at least four rock assemblages: a serpentinite and possibly other ophiolitic rocks of Early or pre-Arenig age; a sequence of limestones and conglomerates of Early Arenig age; a succession of dark shales, cherts, quartz wackes, basic lavas and associated volcanogenic sediments of Llanvirn and ? earlier age; and an assemblage of limestones, breccias, conglomerates and arenites with subordinate shales of Caradoc or Ashgill age. At least three assemblages are divided by unconformities and in theirmost general aspect have similarities with coeval rocks in western Ireland.The Highland Border Complex probably formed N of the Midland Valley arc massif in a marginal sea comparable with the Sunda shelf adjacent to Sumatra–Java. Strike-slip and thrust emplacement of the whole Complex in at least four episodes followed the probable generation of all or part of its rocks by pull-apart mechanisms.

Wrench faulting and trap breaching: A case study of the Kizler North Field, Lyon County, Kansas, USA

2021 ◽  
Vol 2 ◽  
pp. 1-14
Author(s):  
Md Nahidul Hasan ◽  
Sally Potter-McIntyre ◽  
Steve Tedesco
Keyword(s):  
Seismic Data ◽  
Water Saturation ◽  
Field Potential ◽  
High Water ◽  
Rift System ◽  
Lower Paleozoic ◽  
Well Location ◽  
Midcontinent Rift System ◽  
Complex Structural ◽  
Wrench Fault

The Kizler North Field in northwest Lyon County, Kansas, is a producing field with structures associated with both uplift of the Ancestral Rockies (Pennsylvanian to early Permian) and reactivation of structures along the Proterozoic midcontinent rift system (MRS), which contributed to the current complex and poorly understood play mechanisms. The Lower Paleozoic dolomitic Simpson Group, Viola Limestone, and “Hunton Group” are the reservoir units within the field. These units have significant vuggy porosity, which is excellent for field potential; however, in places, the reservoir is inhibited by high water saturation. The seismic data show that two late-stage wrench fault events reactivated existing faults. The observed wrench faults exhibit secondary P, R’, and R Riedel shears, which likely resulted from Central Kansas uplift-MRS wrenching. The latest stage event breached reservoir caprock units during post-Mississippian to pre-Desmoinesian time and allowed for hydrocarbon migration out of the reservoirs. Future exploration models of the Kizler North and analog fields should be based on four play concepts: 1) four-way closure with wrench-fault-related traps, 2) structural highs in the Simpson Group and Viola Limestone, 3) thick “Hunton Group,” and 4) presence of a wrench fault adjacent to the well location that generates subtle closure but not directly beneath it, which causes migration out of reservoirs. In settings where complex structural styles are overprinted, particular attention should be paid to the timing of events that may cause breaches of seals in some structures but not others. Mapping the precise location and vertical throw of the reactivated wrench faults using high-resolution seismic data can help reduce the drilling risk in analog systems.

scholarly journals Geology of the Upper Jurassic to Lower Cretaceous geothermal aquifers in the West Netherlands Basin – an overview

2020 ◽  
Vol 99 ◽  
Author(s):  
Cees J.L. Willems ◽  
Andrea Vondrak ◽  
Harmen F. Mijnlieff ◽  
Marinus E. Donselaar ◽  
Bart M.M. van Kempen
Keyword(s):  
Lower Cretaceous ◽  
Cold Water ◽  
Upper Jurassic ◽  
The West ◽  
Geothermal Heat ◽  
Sequence Stratigraphic ◽  
Tectonic History ◽  
Water Breakthrough ◽  
Hydrocarbon Fields ◽  
Sedimentary Aquifer

Abstract In the past 10 years the mature hydrocarbon province the West Netherlands Basin has hosted rapidly expanding geothermal development. Upper Jurassic to Lower Cretaceous strata from which gas and oil had been produced since the 1950s became targets for geothermal exploitation. The extensive publicly available subsurface data including seismic surveys, several cores and logs from hundreds of hydrocarbon wells, combined with understanding of the geology after decades of hydrocarbon exploitation, facilitated the offtake of geothermal exploitation. Whilst the first geothermal projects proved the suitability of the permeable Upper Jurassic to Lower Cretaceous sandstones for geothermal heat production, they also made clear that much detail of the aquifer geology is not yet fully understood. The aquifer architecture varies significantly across the basin because of the syn-tectonic sedimentation. The graben fault blocks that contain the geothermal targets experienced a different tectonic history compared to the horst and pop-up structures that host the hydrocarbon fields from which most subsurface data are derived. Accurate prediction of the continuity and thickness of aquifers is a prerequisite for efficient geothermal well deployment that aims at increasing heat recovery while avoiding the risk of early cold-water breakthrough. The potential recoverable heat and the current challenges to enhance further expansion of heat exploitation from this basin are evident. This paper presents an overview of the current understanding and uncertainties of the aquifer geology of the Upper Jurassic to Lower Cretaceous strata and discusses new sequence-stratigraphic updates of the regional sedimentary aquifer architecture.

Regional and local controls on Archean rock-hosted cobalt mineralization at the McAra deposit, southern Superior Province, Ontario, Canada

2020 ◽  
Vol 57 (12) ◽  
pp. 1447-1462
Author(s):  
Michael D. Hendrickson
Keyword(s):  
Regional Scale ◽  
Massive Sulfide ◽  
Fault System ◽  
Geochemical Data ◽  
High Grade ◽  
Aeromagnetic Data ◽  
Archean Rock ◽  
Oxidation Reduction ◽  
Mineralized Zone ◽  
Scale Data

The McAra deposit is in eastern Ontario, Canada, and is hosted in an Archean inlier to the Paleoproterozoic Huronian basin. It is currently estimated to contain ∼2.4 million pounds of cobalt at an average grade of 1.25%. New drill data show the mineralized zone comprises glaucodot–cobaltite veins and breccias that transect a mafic–siliciclastic volcanogenic massive sulfide (VMS) deposit. The high cobalt grade and host stratigraphy at the McAra deposit contrast with five-element (Ag–Co–Ni–Bi–As) deposits at the Cobalt and Gowganda camps in the region that produced high-grade silver and by-product cobalt from veins spatially associated with Nipissing Gabbro intrusions. However, geochemical data from recent core samples alongside fluid inclusion and mineralogical data suggest the cobalt zone at McAra and the five-element veins share a similar metal assemblage and were deposited from similar fluids. The mafic–siliciclastic VMS deposit at McAra contains anomalous amounts of cobalt, suggesting the Archean host stratigraphy was the source for the high-grade cobalt zone. Basin brines in the Paleoproterozoic are interpreted to have leached cobalt from Archean rocks and then redeposited it through oxidation–reduction reactions along synvolcanic faults that controlled earlier VMS deposit formation. High-resolution aeromagnetic data show that McAra is immediately adjacent to a mafic dike that transects the Huronian basin along a northwest-striking, crustal-scale fault system. These data, alongside observations from field mapping, also suggest the deposit is on the margin of a sub-basin that contains an 80 km2 Nipissing sill that may have originally overlain the deposit area and been a hydrologic seal during mineralization. The new deposit- and regional-scale data and interpretations are used to create a model for the McAra deposit and provide evidence for why it is cobalt-rich relative to other five-element veins. The model and data can be used to guide exploration for additional cobalt-rich deposits in the region and similar settings globally.

An integrated approach to the Surat Basin stratigraphy

2019 ◽  
Vol 59 (2) ◽  
pp. 940
Author(s):  
Mark Reilly ◽  
Suzanne Hurter ◽  
Zsolt Hamerli ◽  
Claudio L. de Andrade Vieira Filho ◽  
Andrew LaCroix ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Coal Seam ◽  
Methodological Approach ◽  
Regional Scale ◽  
Integrated Approach ◽  
Field Scale ◽  
Coal Seam Gas ◽  
Sequence Stratigraphic ◽  
Flow Models ◽  
Lithostratigraphic Units

The stratigraphy of the Surat Basin, Queensland, has historically been sub-divided by formation and unit nomenclature with a few attempts by other authors to apply sequence stratigraphy to existing formation boundaries. At a local- to field-scale, lithostratigraphy may be able to represent stratigraphy well, but at regional-scale, lithostratigraphic units are likely to be diachronous. To date, this lithology-driven framework does not accurately reflect time relationships in the sub-surface. An entirely new integrated methodological approach, involving well tied seismic data and sequence stratigraphic well-to-well correlations compared with published zircon age dates, has been applied to hundreds of deep wells and shallower coal seam gas wells. This method sub-divides the Surat Basin stratigraphy into defendable 2nd order to 3rd order sequence stratigraphic cycles and has required the use of an alpha-numeric sequence stratigraphic nomenclature to adequately and systematically label potential time equivalent surfaces basin-wide. Correlation of wells is the first step in building models of aquifers and coal seam gas fields for numerical simulation of fluid flow, which is necessary for responsible resource management. Lithostratigraphic correlations will overestimate the extent and hydraulic connectedness of the strata of interest. The result may be fluid flow models that do not represent a realistic pressure footprint of the flow. The present sequence stratigraphic method more accurately reflects the disconnectedness of sub-surface coals and sandstones (aquifers) on a field-to-field scale, adjacent field-scale, and basin-wide scale. It forms the basis for improved and more representative modelling of the sub-surface.

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