THE STRATIGRAPHY OF THE BASAL TRIASSIC SANDSTONE, NORTH PERTH BASIN, WESTERN AUSTRALIA

1971 ◽  
Vol 11 (1) ◽  
pp. 59
Author(s):  
P. Hosemann

The Basal Triassic Sandstone is the basal member of the Lower Triassic Kockatea Shale. It is widely distributed adjacent to, and on the Precambrian Greenough Block in the northern Perth Basin, Western Australia. This member is lowermost Lower Triassic in age in the subsurface of the Don-gara gas field. In outcrop on the Greenough Block, the member is represented by a thin basal conglomerate, conformably overlain by upper Lower Triassic Kockatea Shale. In this stratigraphic study, detailed well-to-well correlations and lithologic studies were integrated to reconstruct the depositional history of the interval encompassing the Basal Triassic Sandstone. This sandstone is a composite of near-shore marine, and strand line accumulations deposited around the flanks and on the Greenough Block during a Lower Triassic marine transgression. The sandstone bodies were deposited on a drowned, topography of low relief, on progressively truncated Permian formations and Precambrian basement. The topography was formed following uplift and tilting of the Greenough Block and the overlying Lower Permian formations during mild Upper Permian tectonism.

1989 ◽  
Vol 143 ◽  
pp. 21-45
Author(s):  
L Stemmerik ◽  
E Håkansson

A lithostratigraphic scheme is erected for the Lower Carboniferous to Triassic sediments of the Wandel Sea Basin, from Lockwood Ø in the west to Holm Land in the east. The scheme is based on the subdivision into the Upper Carboniferous - Lower Permian Mallemuk Mountain Group and the Upper Permian - Triassic Trolle Land Group. In addition the Upper Carboniferous Sortebakker Formation and the Upper Permian Kap Kraka Formation are defined. Three formations and four members are included in the Mallemuk Mountain Group. Lithostratigraphic units include: Kap Jungersen Formation (new) composed of interbedded limestones, sandstones and shales with minor gypsum - early Moscovian; Foldedal Formation composed of interbedded limestones and sandstones -late Moseovian to late Gzhelian; Kim Fjelde Formation composed of well bedded Iimestones - late Gzhelian to Kungurian. The Trolle Land Group includes three formations: Midnatfjeld Formation composed of dark shales, sandstones and limestones - Late Permian; Parish Bjerg Formation composed of a basal conglomeratic sandstone overlain by shales and sandstones - ?Early Triassic (Scythian); Dunken Formation composed of dark shales and sandstones - Triassic (Scythian-Anisian). The Sortebakker Formation (new) is composed of interbedded sandstones, shales and minor coal of floodplain origin. The age is Early Carboniferous. The Kap Kraka Formation (new) includes poorly known hematitic sandstones, conglomerates and shales of Late Permian age.


2003 ◽  
Vol 20 (1) ◽  
pp. 691-698
Author(s):  
M. J. Sarginson

AbstractThe Clipper Gas Field is a moderate-sized faulted anticlinal trap located in Blocks 48/19a, 48/19c and 48/20a within the Sole Pit area of the southern North Sea Gas Basin. The reservoir is formed by the Lower Permian Leman Sandstone Formation, lying between truncated Westphalian Coal Measures and the Upper Permian evaporitic Zechstein Group which form source and seal respectively. Reservoir permeability is very low, mainly as a result of compaction and diagenesis which accompanied deep burial of the Sole Pit Trough, a sub basin within the main gas basin. The Leman Sandstone Formation is on average about 715 ft thick, laterally heterogeneous and zoned vertically with the best reservoir properties located in the middle of the formation. Porosity is fair with a field average of 11.1%. Matrix permeability, however, is less than one millidarcy on average. Well productivity depends on intersecting open natural fractures or permeable streaks within aeolian dune slipface sandstones. Field development started in 1988. 24 development wells have been drilled to date. Expected recoverable reserves are 753 BCF.


2016 ◽  
Vol 56 (1) ◽  
pp. 29 ◽  
Author(s):  
Neil Tupper ◽  
Eric Matthews ◽  
Gareth Cooper ◽  
Andy Furniss ◽  
Tim Hicks ◽  
...  

The Waitsia Field represents a new commercial play for the onshore north Perth Basin with potential to deliver substantial reserves and production to the domestic gas market. The discovery was made in 2014 by deepening of the Senecio–3 appraisal well to evaluate secondary reservoir targets. The well successfully delineated the extent of the primary target in the Upper Permian Dongara and Wagina sandstones of the Senecio gas field but also encountered a combination of good-quality and tight gas pay in the underlying Lower Permian Kingia and High Cliff sandstones. The drilling of the Waitsia–1 and Waitsia–2 wells in 2015, and testing of Senecio-3 and Waitsia-1, confirmed the discovery of a large gas field with excellent flow characteristics. Wireline log and pressure data define a gross gas column in excess of 350 m trapped within a low-side fault closure that extends across 50 km2. The occurrence of good-quality reservoir in the depth interval 3,000–3,800 m is diagenetically controlled with clay rims inhibiting quartz cementation and preserving excellent primary porosity. Development planning for Waitsia has commenced with the likelihood of an early production start-up utilising existing wells and gas processing facilities before ramp-up to full-field development. The dry gas will require minimal processing, and access to market is facilitated by the Dampier–Bunbury and Parmelia gas pipelines that pass directly above the field. The Waitsia Field is believed to be the largest conventional Australian onshore discovery for more than 30 years and provides impetus and incentive for continued exploration in mature and frontier basins. The presence of good-quality reservoir and effective fault seal was unexpected and emphasise the need to consider multiple geological scenarios and to test unorthodox ideas with the drill bit.


1971 ◽  
Vol 11 (1) ◽  
pp. 90
Author(s):  
K. J. Bird ◽  
W. F. Coleman ◽  
H. Crocker

Four-arm dipmeter interpretation has been integrated with other wireline logs, lithologic and palaeontologic data, and regional geology to arrive at a history of the deposition in a portion of the North Perth Basin.The Permian sediments were deposited in a moderate to low energy, paralic to marine environment. They were unconformably overlain by a thin transgressive Lower Triassic sand and deepwater marine shale. The Middle Triassic sediments were deposited as a regressive marine sequence under the influence of a strong southwesterly uplift, and culminated in piedmont talus deposits of Upper Triassic age.In the Lower Jurassic this area evolved through a flood-plain environment to a paralic environment with a northeast-southwest oriented coastline and a northern source area. During the Middle Jurassic gentle crustal movements, coupled with an increasingly active northern and eastern source area, resulted in several cycles of nearshore deposition, and finally a marine transgression.Subsequent violent tectonic uplift to the east in the Upper Jurassic produced massive first generation sands which were deposited in a mainly continental environment.


1988 ◽  
Vol 28 (1) ◽  
pp. 88 ◽  
Author(s):  
B.J. Warris

The Mount Horner oilfield is located 30 km east of the town of Dongara, some 360 km north of Perth, Western Australia. It was discovered by WAPET in 1965 but it was not until 1980-81 that a further four appraisal wells were drilled on the field. One additional appraisal well was drilled in 1987.The structure consists of a tilted fault block downthrown to the east with a roll-over anticline on the downthrown side of the fault. Sandstones within the Lower Triassic Kockatea Shale produced oil in 1965 from Mount Horner No. 1 on the upthrown tilted fault block. This well was eventually plugged and abandoned due to the low productivity of the reservoirs and the then prevailing low oil price. Production also occurred in the Basal Triassic Sandstone on the downthrown side of the fault. Mount Horner Nos 4 and 5 produced from this horizon from 1984 to 1986, when they were shut in due to increasing water cut.At the top of the Lower to Middle Jurassic Cockleshell Gully Formation, a complex transition zone exists between the fluvial sandstones of the Cattamarra Coal Measures Member and the marine sediments of the Champion Bay Group. Sandstones in this transition zone produce oil from Mount Horner No. 5 which was re-completed in 1986 and from No. 7 which was drilled in 1987.There are four distinct oil pools on the Mount Horner structure. Geochemical and maturation studies have shown that the bulk of the reserves was generated from the basal part of the Kockatea Shale and has migrated up the main fault and into the Jurassic reservoirs.Recent workover and appraisal drilling programs on the field have established the first commercial oil production from Jurassic sediments in the Perth Basin. This opens up an exciting new exploration play in the northern Perth Basin.


1982 ◽  
Vol 19 (1) ◽  
pp. 68-80 ◽  
Author(s):  
Ouyang Shu

In eastern Yunnan the Upper Permian Lungtan and Changhsing Formations and the Lower Triassic Kayitou Formation each contain a characteristic assemblage of spores and pollen.The Torispora gigantea – Patellisporites meishanensis assemblage in the Lungtan Formation contains abundant pteridophyte and pteridosperm spores and few gymnosperm pollen. Some genera are known from the Carboniferous and Lower Permian of Europe but most are Cathaysian. The Yunnanospora radiata – Gardenasporites assemblage in the Changhsing Formation has a Paleozoic aspect but characteristic Mesozoic genera and species occur. The Lundbladispora–Aratrisporites–Pteruchipollenites assemblage in the Kayitou Formation contains numerous pteridophyte and pteriodosperm spores and gymnosperm pollen; some Paleozoic genera occur (Crassispora, Lycospora?, Stellisporites, Thymospora, Torispora, Triparites, Triquitrites, and Waltzispora), but Mesozoic genera predominate. Thirty metres above the base of the Kayitou Formation gymnosperm pollen, especially that of conifers, becomes dominant.It is suggested that the Carboniferous and Lower Permian species in the Changhsing Formation and the Paleozoic genera in the Kayitou Formation are not reworked but are indigenous and that the composition of the resulting microflora reflects the parent flora. The presence of this microflora in Lower Triassic rocks suggests that, at least locally, sedimentation was essentially continuous across the Permian–Triassic boundary.


1991 ◽  
Vol 14 (1) ◽  
pp. 417-423 ◽  
Author(s):  
R. T. Farmer ◽  
A. P. Hillier

AbstractThe Clipper Gas Field is a moderate-sized faulted anticlinal trap located in Blocks 48/19a and 48/19c within the Sole Pit area of the southern North Sea gas basin. The reservoir is formed by the Lower Permian Leman Sandstone Formation, lying between truncated Westphalian Coal Measures and the Upper Permian evaporitic Zechstein Group which form source and seal respectively. Reservoir permeability is very low, mainly as a result of compaction and diagenesis which accompanied deep burial of the Sole Pit Trough, a sub-basin within the main gas basin. The Leman Sandstone Fm. is on average about 715 ft thick, laterally heterogeneous and zoned vertically with the best reservoir properties about the middle of the formation. Porosity is fair with a field average of 11.1%. Matrix permeability, however, is less than 1 millidarcy on average and is so low that some intervals in the field will not flow gas unless stimulated. Steep dipping zones of natural fractures occur in certain areas of the field; these commonly allow high flow rates to be achieved from large blocks of low-permeability matrix. Expected recoverable reserves from the most favourable part of the field are 558 BCF and Clipper Field is now being developed in conjunction with part of the adjacent Barque Gas Field. Later development of the remainder of Clipper Field will depend upon reservoir performance in the initial development area.


2003 ◽  
Vol 77 (2) ◽  
pp. 389-392 ◽  
Author(s):  
Graciela Piñeiro ◽  
Mariano Verde ◽  
Martín Ubilla ◽  
Jorge Ferigolo

In their monograph Review of the Pelycosauria, Romer and Price (1940), proposed that the earliest synapsids (“pelycosaurs”) were cosmopolitan, despite the observation that amniotes appeared to be restricted to the paleotropics during the Late Carboniferous and Early Permian (290–282 Ma). Romer and Price (1940) accounted for the scarcity of terrestrial tetrapods, including “pelycosaurs,” in Lower Permian beds elsewhere to the absence of coeval continental deposits beyond North America and Europe. Indeed, most workers recognized a geographical and temporal gap between Permo-Carboniferous “pelycosaurs” and therapsid synapsids. Recent research has confirmed that varanopid and caseid “pelycosaurs” were components of therapsid-dominated Late Permian faunas preserved in Russia and South-Africa (Tatarinov and Eremina, 1975; Reisz, 1986; Reisz et al., 1998; Reisz and Berman, 2001).


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