BURIAL HISTORY OF THE EASTERN OFFICER BASIN, SOUTH AUSTRALIA

1995 ◽  
Vol 35 (1) ◽  
pp. 307 ◽  
Author(s):  
R. Moussavi-Harami ◽  
D. I. Gravestock

The intracratonic Officer Basin of central Australia was formed during the Neoproterozoic, approximately 820 m.y. ago. The eastern third of the Officer Basin is in South Australia and contains nine unconformity-bounded sequence sets (super-sequences), from Neoproterozoic to Tertiary in age. Burial history is interpreted from a series of diagrams generated from well data in structurally diverse settings. These enable comparison between the stable shelf and co-existing deep troughs. During the Neoproterozoic, subsidence in the north (Munyarai Trough) was much higher than in either the south (Giles area) or northeast (Manya Trough). This subsidence was related to tectonic as well as sediment loading. During the Cambrian, subsidence was much higher in the northeast and was probably due to tectonic and sediment loading (carbonates over siliciclastics). During the Early Ordovician, subsidence in the north created more accommodation space for the last marine transgression from the northeast. The high subsidence rate of Late Devonian rocks in the Munyarai Trough was probably related to rapid deposition of fine-grained siliciclastic sediments prior to the Alice Springs Orogeny. Rates of subsidence were very low during the Early Permian and Late Jurassic to Early Cretaceous, probably due to sediment loading rather than tectonic sinking. Potential Neoproterozoic source rocks were buried enough to reach initial maturity at the time of the terminal Proterozoic Petermann Ranges Orogeny. Early Cambrian potential source rocks in the Manya Trough were initially mature prior to the Delamerian Orogeny (Middle Cambrian) and fully mature on the Murnaroo Platform at the culmination of the Alice Springs Orogeny (Devonian).

2018 ◽  
Vol 36 (5) ◽  
pp. 1229-1244
Author(s):  
Xiao-Rong Qu ◽  
Yan-Ming Zhu ◽  
Wu Li ◽  
Xin Tang ◽  
Han Zhang

The Huanghua Depression is located in the north-centre of Bohai Bay Basin, which is a rift basin developed in the Mesozoic over the basement of the Huabei Platform, China. Permo-Carboniferous source rocks were formed in the Huanghua Depression, which has experienced multiple complicated tectonic alterations with inhomogeneous uplift, deformation, buried depth and magma effect. As a result, the hydrocarbon generation evolution of Permo-Carboniferous source rocks was characterized by discontinuity and grading. On the basis of a detailed study on tectonic-burial history, the paper worked on the burial history, heating history and hydrocarbon generation history of Permo-Carboniferous source rocks in the Huanghua Depression combined with apatite fission track testing and fluid inclusion analyses using the EASY% Ro numerical simulation. The results revealed that their maturity evolved in stages with multiple hydrocarbon generations. In this paper, we clarified the tectonic episode, the strength of hydrocarbon generation and the time–spatial distribution of hydrocarbon regeneration. Finally, an important conclusion was made that the hydrocarbon regeneration of Permo-Carboniferous source rocks occurred in the Late Cenozoic and the subordinate depressions were brought forward as advantage zones for the depth exploration of Permo-Carboniferous oil and gas in the middle-northern part of the Huanghua Depression, Bohai Bay Basin, China.


Author(s):  
P.J. Lee

A basin or subsurface study, which is the first step in petroleum resource evaluation, requires the following types of data: • Reservoir data—pool area, net pay, porosity, water saturation, oil or gas formation volume factor, in-place volume, recoverable oil volume or marketable gas volume, temperature, pressure, density, recovery factors, gas composition, discovery date, and other parameters (refer to Lee et al., 1999, Section 3.1.2). • Well data—surface and bottom well locations; spud and completion dates; well elevation; history of status; formation drill and true depths; lithology; drill stem tests; core, gas, and fluid analyses; and mechanical logs. • Geochemical data—types of source rocks, burial history, and maturation history. • Geophysical data—prospect maps and seismic sections. Well data are essential when we construct structural contour, isopach, lithofacies, porosity, and other types of maps. Geophysical data assist us when we compile number-of-prospect distributions and they provide information for risk analysis.


2020 ◽  
Author(s):  
Benjamin Bellwald ◽  
Sverre Planke ◽  
Sunil Vadakkepuliyambatta ◽  
Stefan Buenz ◽  
Christine Batchelor ◽  
...  

<p>Sediments deposited by marine-based ice sheets are dominantly fine-grained glacial muds, which are commonly known for their sealing properties for migrating fluids. However, the Peon and Aviat hydrocarbon discoveries in the North Sea show that coarse-grained glacial sands can occur over large areas in formerly glaciated continental shelves. In this study, we use conventional and high-resolution 2D and 3D seismic data combined with well information to present new models for large-scale fluid accumulations within the shallow subsurface of the Norwegian Continental Shelf. The data include 48,000 km<sup>2</sup> of high-quality 3D seismic data and 150 km<sup>2</sup> of high-resolution P-Cable 3D seismic data, with a vertical resolution of 2 m and a horizontal resolution of 6 to 10 m in these data sets. We conducted horizon picking, gridding and attribute extractions as well as seismic geomorphological interpretation, and integrated the results obtained from the seismic interpretation with existing well data.</p><p>The thicknesses of the Quaternary deposits vary from hundreds of meters of subglacial till in the Northern North Sea to several kilometers of glacigenic sediments in the North Sea Fan. Gas-charged, sandy accumulations are characterized by phase-reserved reflections with anomalously high amplitudes in the seismic data as well as density and velocity decreases in the well data. Extensive (>10 km<sup>2</sup>) Quaternary sand accumulations within this package include (i) glacial sands in an ice-marginal outwash fan, sealed by stiff glacial tills deposited by repeated glaciations (the Peon discovery in the Northern North Sea), (ii) sandy channel-levee systems sealed by fine-grained mud within sequences of glacigenic debris flows, formed during shelf-edge glaciations, (iii) fine-grained glacimarine sands of contouritic origin sealed by gas hydrates, and (iv) remobilized oozes above large evacuation craters and sealed by megaslides and glacial muds. The development of the Fennoscandian Ice Sheet resulted in a rich variety of depositional environments with frequently changing types and patterns of glacial sedimentation. Extensive new 3D seismic data sets are crucial to correctly interpret glacial processes and to analyze the grain sizes of the related deposits. Furthermore, these data sets allow the identification of localized extensive fluid accumulations within the Quaternary succession and distinguish stratigraphic levels favorable for fluid accumulations from layers acting as fluid barriers.</p>


2012 ◽  
Vol 91 (4) ◽  
pp. 535-554 ◽  
Author(s):  
R. Abdul Fattah ◽  
J.M. Verweij ◽  
N. Witmans ◽  
J.H. ten Veen

Abstract3D basin modelling is used to investigate the history of maturation and hydrocarbon generation on the main platforms in the northwestern part of the offshore area of the Netherlands. The study area covers the Cleaverbank and Elbow Spit Platforms. Recently compiled maps and data are used to build the input geological model. An updated and refined palaeo water depth curve and newly refined sediment water interface temperatures (SWIT) are used in the simulation. Basal heat flow is calculated using tectonic models. Two main source rock intervals are defined in the model, Westphalian coal seams and pre-Westphalian shales, which include Namurian and Dinantian successions. The modelling shows that the pre-Westphalian source rocks entered the hydrocarbon generation window in the Late Carboniferous. In the southern and central parts of the study area, the Namurian started producing gas in the Permian. In the north, the Dinantian source rocks appear to be immature. Lower Westphalian sediments started generating gas during the Upper Triassic. Gas generation from Westphalian coal seams increased during the Paleogene and continues in present-day. This late generation of gas from Westphalian coal seams is a likely source for gas accumulations in the area.Westphalian coals might have produced early nitrogen prior to or during the main gas generation occurrence in the Paleogene. Namurian shales may be a source of late nitrogen after reaching maximum gas generating phase in the Triassic. Temperatures reached during the Mid Jurassic were sufficiently high to allow the release of non-organic nitrogen from Namurian shales.


1979 ◽  
Vol 27 (3) ◽  
pp. 479 ◽  
Author(s):  
R Freitag

Australian components of the subfamilies Collyrinae and Cicindelinae, tribes Collyrini, Megacephalini and Cicindelini, and genera Tricondyla Latreille, Megacephala Latreille, Distipsidera Westwood, Rhysopleura Sloane, Nickerlea W. Horn, and Cicindela Linne are distinguished in a key. For each of the first five genera, numbers of Australian species, geographical distributions, and habitats of the adults are described. Diagnostic characteristics are provided for the genus Cicindela Linne. Twenty-nine Australian species are arranged in seven species-groups as follows: the iosceles group, six species; the nigrina group, two species: the carnarvona, group (=subgenus Grandopronotalia W. Horn, genus Prothyma), one species, C. carnarvona, sp. et comb. nov.; the tetragramma group, seven species, including C. levitetragramma, sp. nov. (type locality, Western Australia, Port Hedland); the ypsilon group, four species; the igneicollis group, five species, including C. gairdneri, sp. nov. (type locality, South Australia, Lake Gairdner, south-west gulf); the semicincta group, four species, including C. parasemicincta, sp. nov. (type locality, South Australia, Wobna Mound Spring about 8km south-east of Coward Spring). Placement of the iosceles and carnarvona groups is discussed. A key is provided for all species and five subspecies. Species-groups, species, and subspecies are revised, described and illustrated, and the ranges of species indicated by maps. A history of the Australian species of Cicindela is derived, which comprises a reconstructed phylogeny, based on adult characteristics, and zoogeography based on patterns of geographical distributions of species-groups, ecological requirements, vicariance relations of sister groups, and climatic events of the past. It is concluded that five species-groups are endemic to Australia. Their origins are unknown, though geographical distributions indicate that four (iosceles, nigrina, tetragramma, carnarvona) are relicts of extinct Oriental lineages, and one (igneicollis) is relict of a south ancient lineage. Two species-groups (ypsilon, semicincta) are southernmost extensions of extant Oriental groups. Zoogeographical evidence suggests that most founding stocks invaded northern Australia through New Guinea during the Tertiary and Pleistocene, and speciation in the Pleistocene has been generated in the north-east by periodic retreats and invasions of the sea in the Gulf of Carpentaria during glacial and interglacial phases.


GeoArabia ◽  
1998 ◽  
Vol 3 (3) ◽  
pp. 339-356
Author(s):  
Penelope A. Milner

ABSTRACT Recent work by Phillips Petroleum in the Southern Arabian Peninsula has elucidated the source potential of the Palaeozoic strata. A group of newly drilled and older wells, together with exclusive and non-exclusive reports, have been used in order to develop improved maturation and migration models for emerging plays, and to gain a better understanding of the subsidence and maturation history of this large and diverse area. It has been possible to conduct comprehensive burial history modelling for a number of wells from Oman, Saudi Arabia and the United Arab Emirates. This, together with the modelling of hypothetical wells derived from depth structure maps, has improved our understanding of oil- and gas-prone source rocks in the Cretaceous, Jurassic and Palaeozoic strata. The resultant maturity distribution has been developed with the aid of a more detailed structural model for the Southern Arabian Peninsula. In tandem with this study, available cores and cuttings were analysed to measure source rock total organic carbon, maturity and richness parameters and summarised using proprietary techniques. It is concluded that the Jurassic Hanifa Formation is less mature and not source facies to the south and west of the Rub’ Al-Khali. The oil and gas mature source facies is present in the north and east of the Rub’ Al-Khali and in the Western Emirates. In addition, it is concluded that the oil mature Silurian source facies is confined to the narrow southern and western margins of the Rub’ Al-Khali. Outside this area the overmature area is in the core of the Rub’ Al-Khali extending northeast to the United Arab Emirates. The remaining area is modelled as gas mature in western Saudi Arabia and Qatar.


2016 ◽  
Author(s):  
Daniel Trümpy ◽  
Jan Witte ◽  
Immanuel Weber ◽  
João P. Da Ponte Souza

ABSTRACT In total, some 60 wells have been drilled onshore and less than 10 offshore Somalia*, none of which in deep water. Several prospective basins remain undrilled, such as the offshore Jubba and Mid Somali High basins and the onshore Odewayne basin. In view of the gas discoveries offshore Mozambique and Tanzania, and also of encouraging results offshore Kenya (sub-commercial oil discovery Sunbird-1) and in Madagascar, the Somalian offshore and onshore basins were re-evaluated. As to the Somali onshore basins, the extension of the Yemeni Jurassic and Cretaceous rifts into Somalia highlights their prospectivity. Seeps abound (Odewayne and Nogal basins) and some wells encountered good shows. Late Jurassic and Upper Cretaceous marine shales are source rock candidates. Gas in the area of Mogadishu may be associated with the Early Triassic Bokh Fm. source rock. Seeps in western Somalia are rare, and may result either from long-distance migration out of the Calub Graben or from locally mature Lower Cretaceous or Upper Jurassic. We establish an inventory of proven and possible source rock occurences in Somalia by integrating publicly available data on slicks and seeps, geological and gravity maps, literature data, well data and geological information from adjoining basins. Our data indicate that in the Somali part of the Gulf of Aden, high heat-flow may critically affect the Late Jurassic source rock. However, Late Cretaceous or even Eocene sources may be locally oil-mature. The presence of source rocks on the Somali Indian Ocean margin remains presently speculative. Abundance of slicks in the area south of Mogadishu may not relate to hydrocarbons. Of more interest are reported isolated slicks further to the north, in deeper waters of the Mogadishu and Mid-Somalia High Basins. These slicks may be related to Lower/Mid-Jurassic, Late Jurassic, Late Cretaceous or Eocene sources. Analysis of onshore seeps in northern Somalia (Nogal, Daroor, Odewayne basins), integrated with seismic data, will allow to determine the origin of these oils and an assessment of the size of prospective kitchen areas. In the offshore, 3D-Basin-modelling will be required to determine which areas are prospective for gas or, especially, for oil.


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