PETROLEUM SYSTEMS IN TASMANIA'S FRONTIER ONSHORE BASINS

2000 ◽  
Vol 40 (1) ◽  
pp. 26
Author(s):  
M.R. Bendall C.F. Burrett ◽  
H.J. Askin
Keyword(s):  
Oil And Gas ◽  
Source Rocks ◽  
Petroleum Exploration ◽  
Late Triassic ◽  
Upper Permian ◽  
Lower Permian ◽  
Peak Oil ◽  
Petroleum Systems ◽  
Upper Proterozoic ◽  
Oil Seep

Sedimentary successions belonging to three petroleum su persy stems can be recognised in and below the Late Carboniferous to Late Triassic onshore Tasmania Basin. These are the Centralian, Larapintine and Gondwanan. The oldest (Centralian) is poorly known and contains possible mature source rocks in Upper Proterozoic dolomites. The Larapintine 2 system is represented by rocks of the Devonian fold and thrust belt beneath the Tasmania Basin. Potential source rocks are micrites and shales within the 1.8 km-thick tropical Ordovician Gordon Group carbonates. Conodont CAI plots show that the Gordon Group lies in the oil and gas windows over most of central Tasmania and probably under much of the Tasmania Basin. Potential reservoirs are the upper reefal parts of the Gordon Group, paleokarsted surfaces within the Gordon Group and the overlying sandstones of the Siluro-Devonian Tiger Range and Eldon Groups. Seal rocks include shales within the Siluro-Devonian and Upper Carboniferous-Permian tillites and shales.The Gondwanan supersystem is the most promising supersystem for petroleum exploration within the onshore Tasmania Basin. It is divided into two petroleum systems— the Early Permian Gondwanan 1 system, and the Late Permian to Triassic Gondwanan 2 system. Excellent source rocks occur in the marine Tasmanite Oil Shale and other sections within the Lower Permian Woody Island and Quamby Formations of the Gondwanan 1 system and within coals and freshwater oil shales of the Gondwanan 2 system. These sources are within the oil and gas windows across most of the basin and probably reached peak oil generation at about 100 Ma. An oil seep, sourced from a Tasmanites-rich, anoxic shale, is found within Jurassic dolerite 40 km WSW of Hobart. Potential Gondwanan 1 reservoirs are the glaciofluvial Faulkner Group sandstones and sandstones and limestones within the overlying parts of the glaciomarine Permian sequence. The Upper Permian Ferntree Mudstone Formation provides an effective regional seal. Potential Gondwanan 2 reservoirs are the sandstones of the Upper Permian to Norian Upper Parmeener Supergroup. Traps consisting of domes, anticlines and faults were formed probably during the Early Cretaceous. Preliminary interpretation of a short AGSO seismic profile in the Tasmania Basin shows that, contrary to earlier belief, structures can be mapped beneath extensive and thick (300 m) sills of Jurassic dolerite. In addition, the total section of Gondwana to Upper Proterozoic to Triassic sediments appears to be in excess of 8,500 m. These recent studies, analysis of the oil seep and drilling results show that the Tasmanian source rocks have generated both oil and gas. The Tasmania Basin is considered prospective for both petroleum and helium and is comparable in size and stratigraphy to other glaciomarine-terrestrial Gondwanan basins such as the South Oman and Cooper Basins.

SIMPSON DESERT SUB-BASIN—A PROMISING PERMIAN TARGET

1973 ◽  
Vol 13 (1) ◽  
pp. 33
Author(s):  
George E. Williams
Keyword(s):  
Lower Jurassic ◽  
Source Rocks ◽  
Petroleum Exploration ◽  
Seismic Exploration ◽  
Upper Permian ◽  
Lower Permian ◽  
Geophysical Surveys ◽  
Carbonaceous Shales ◽  
Cap Rock ◽  
Simpson Desert

Sediments of three major basins occur in the Simpson Desert region of central Australia:Cambro -Ordovician dolomites and sandstones, and Siluro- Devonian conglomerates, sandstones and shales, related to the Amadeus Basin:Permian conglomerates, sandstones, shales and coals of the Simpson Desert Sub-basin, the extensive eastern lobe of the Pedirka Basin:Mesozoic sandstones and shales of the Eromanga Basin.Principal petroleum exploration interest is presently directed toward the Permian sediments, which have many features in common with the petroleum producing Permian section of the neighbouring Cooper Basin.Lower Permian sediments known from drilling in the Simpson Desert Sub-basin comprise glaciofluvial conglomerates and sandstones overlain by fluvial and lacustrine sandstones, silt-stones, shales and coals. The maximum thickness encountered in wells is 1,479 ft (448 m) in Mokari 1.Recent seismic exploration 50 to 100 mi (80-160 km) west of Poeppel Corner in the deeper part of the Simpson Desert Sub-basin indicates that an additional sediment package up to 1,500 ft (350 m) thick occurs at depths of 6,500 to 7,500 ft (2,000-2,300 m) between Lower Permian and Lower Jurassic sections. This sediment package, nowhere penetrated by drilling, may be Middle to Upper Permian and/or Triassic in age. It is of great significance to petroleum exploration in the sub-basin and substantially upgrades the hydrocarbon prospects of the region.Permian sediments in the Simpson Desert Sub-basin thin by onlap, wedge out and stripping over the crests of anticlinal growth structures. Crestal sediments probably comprise mainly porous sandstones, grading off-structure into thicker sequences containing carbonaceous shales and coals. Such carbonaceous potential source rocks are probably best developed in the deepest part of the sub-basin, where Triassic cap rock may also be present. Two particularly promising drilling targets—the Colson Anticline and the East Colson Anticline—have been revealed by recent geophysical surveys in this portion of the sub-basin. Wells drilled on these structures may intersect Permo-Triassic sediments up to 2,200 + ft (670 in) thick which are comparable in age and type with producing sections in the Cooper Basin.

PETROLEUM GEOLOGY OF MIDDLE–LATE TRIASSIC AND EARLY JURASSIC SEQUENCES IN THE SIMPSON BASIN AND NORTHERN EROMANGA BASIN OF CENTRAL AUSTRALIA

2007 ◽  
Vol 47 (1) ◽  
pp. 127 ◽  
Author(s):  
G. Ambrose ◽  
M. Scardigno ◽  
A.J. Hill
Keyword(s):  
Oil And Gas ◽  
Regional Scale ◽  
Early Jurassic ◽  
Source Rocks ◽  
Late Triassic ◽  
Red Beds ◽  
Petroleum Systems ◽  
Stratigraphic Architecture ◽  
Central Australia ◽  
Cooper Basin

Prospective Middle–Late Triassic and Early Jurassic petroleum systems are widespread in central Australia where they have only been sparsely explored. These systems are important targets in the Simpson/Eromanga basins (Poolowanna Trough and surrounds), but the petroleum systems also extend into the northern and eastern Cooper Basin.Regional deposition of Early–Middle Triassic red-beds, which provide regional seal to the Permian petroleum system, are variously named the Walkandi Formation in the Simpson Basin, and the Arrabury Formation in the northern and eastern Cooper Basin. A pervasive, transgressive lacustrine sequence (Middle–Late Triassic Peera Peera Formation) disconformably overlies the red-beds and can be correlated over a distance of 500 km from the Poolowanna Trough into western Queensland, thus providing the key to unravelling Triassic stratigraphic architecture in the region. The equivalent sequence in the northern Cooper Basin is the Tinchoo Formation. These correlations allow considerable simplification of Triassic stratigraphy in this region, and demonstrate the wide lateral extent of lacustrine source rocks that also provide regional seal. Sheet-like, fluvial-alluvial sands at the base of the Peera Peera/Tinchoo sequence are prime reservoir targets and have produced oil at James–1, with widespread hydrocarbon shows occurring elsewhere including Poolowanna–1, Colson–1, Walkandi–1, Potiron–1 and Mackillop–1.The Early Jurassic Poolowanna Formation disconformably overlies the Peera Peera Formation and can be subdivided into two transgressive, fluvial-lacustrine cycles, which formed on a regional scale in response to distal sea level oscillations. Early Jurassic stratigraphic architecture in the Poolowanna Trough is defined by a lacustrine shale capping the basal transgressive cycle (Cycle 1). This shale partitions the Early Jurassic aquifer in some areas and significant hydrocarbon shows and oil recoveries are largely restricted to sandstones below this seal. Structural closure into the depositional edge of Cycle 1 is an important oil play.The Poolowanna and Peera Peera formations, which have produced minor oil and gas/condensate on test respectively in Poolowanna–1, include lacustrine source rocks with distinct coal maceral compositions. Significantly, the oil-bearing Early Jurassic sequence in Cuttapirrie–1 in the Cooper Basin correlates directly with the Cycle–1 oil pool in Poolowanna–1. Basin modelling in the latter indicates hydrocarbon expulsion occurred in the late Cretaceous (90–100 Ma) with migration into a subtle Jurassic age closure. Robust Miocene structural reactivation breached the trap leaving only minor remnants of water-washed oil. Other large Miocene structures, bound by reverse faults and some reflecting major inversion, have failed to encounter commercial hydrocarbons. Future exploration should target subtle Triassic to Jurassic–Early Cretaceous age structural and combination stratigraphic traps largely free of younger fault dislocation.

scholarly journals Initiation of petroleum exploration in Jameson Land, East Greenland

1986 ◽  
Vol 128 ◽  
pp. 103-121
Author(s):  
F Surlyk ◽  
S Piasecki ◽  
F Rolle
Keyword(s):  
Lower Triassic ◽  
Scientific Work ◽  
Upper Jurassic ◽  
Source Rocks ◽  
Petroleum Exploration ◽  
Upper Permian ◽  
Lower Permian ◽  
Western Basin ◽  
East Greenland ◽  
Promising Source

Active petroleum exploration in East Greenland is of fairly recent date and was preceded by a much longer history of scientific work and mineral exploration. The discovery in 1948 of lead-zinc mineralisation at Mestersvig resulted in the formation of Nordisk Mineselskab AIS in 1952. In the beginning of the seventies Nordisk Mineselskab initiated cooperation with the American oil company Atlantic Richfield (ARCO) in order to undertake petroleum exploration in Jameson Land. The Jameson Land basin contains a very thick Upper Palaeozoic - Mesozoic sedimentary sequence. Important potential source rocks are Lower Permian lacustrine mudstone, Upper Permian black marine mudstone, Middle Triassic dark marine limestone, uppermost Triassic black marginal marine mudstone, Lower Jurassic black mudstone and Upper Jurassic deep shelf black mudstone. Tbe Upper Permian mudstone, which is the most promising source rock, is immature to weakly mature along the western basin margin and is expected to be in the oil or gas-generating zone when deeply buried in the central part of the basin. Potential reservoir rocks include Upper Permian bank and mound limestones, uppermost Permian fan delta sandstones, Lower Triassic aeolian and braided river sandstones, and Lower, Middle and Upper Jurassic sandstones. The most important trap types are expected to be stratigraphic, such as Upper Permian limestone bodies, or combination stratigraphic-structural such as uppermost Permian or Lower Triassic sandstones in Early Triassic tilted fault blocks. In the offshore areas additional play types are probably to be found in tilted Jurassic fault blocks containing thick Lower, Middle and Upper Jurassic sandstones and lowermost Cretaceous sandstones and conglomerates. The recognition of the potential of the Upper Permian in petroleum exploration in East Greenland has important implications for petroleum exploration on the Norwegian shelf.

Petroleum source rocks of Western Australia

2018 ◽  
Vol 58 (1) ◽  
pp. 282 ◽  
Author(s):  
K. Ameed R. Ghori
Keyword(s):  
Western Australia ◽  
Oil And Gas ◽  
Source Rocks ◽  
Lower Permian ◽  
Burial History ◽  
Canning Basin ◽  
Petroleum Systems ◽  
Northern Carnarvon Basin ◽  
Coal Measures ◽  
Carnarvon Basin

Petroleum geochemical analysis of samples from the Canning, Carnarvon, Officer and Perth basins identified several formations with source potential, the: • Triassic Locker Shale and Jurassic Dingo Claystone of the Northern Carnarvon Basin; • Permian Irwin River Coal Measures and Carynginia Formation, Triassic Kockatea Shale and Jurassic Cattamarra Coal Measures of the Perth Basin; • Ordovician Goldwyer and Bongabinni formations, Devonian Gogo Formation and Lower Carboniferous Laurel Formation of the Canning Basin; • Devonian Gneudna Formation of the Gascoyne Platform and the Lower Permian Wooramel and Byro groups of the Merlinleigh Sub-basin of the Southern Carnarvon Basin; and • Neoproterozoic Brown, Hussar, Kanpa and Steptoe formations of the Officer Basin. Burial history and geothermal basin modelling was undertaken using input parameters from geochemical analyses of rock samples, produced oil, organic petrology, apatite fission track analysis (AFTA), heat flows, subsurface temperatures and other exploration data compiled by the Geological Survey of Western Australia (GSWA). Of these basins, the Canning, Carnarvon, and Perth basins are currently producing oil and gas, whereas the Southern Carnarvon and Officer basins have no commercial petroleum discovery yet, but they do have source, reservoir, seal and petroleum shows indicating the presence of petroleum systems. The Carnarvon Basin contains the richest identified petroleum source rocks, followed by the Perth and Canning basins. Production in the Carnarvon Basin is predominantly gas and oil, the Perth Basin is gas-condensate and the Canning Basin is oil dominated, demonstrating the variations in source rock type and maturity across the state. GSWA is continuously adding new data to assess petroleum systems and prospectivity of these and other basins in Western Australia.

THE SUBSURFACE GEOLOGY OF THE WESTERN OFFICER BASIN — RESULTS OF SHELL'S 1980-1984 PETROLEUM EXPLORATION CAMPAIGN

1985 ◽  
Vol 25 (1) ◽  
pp. 34 ◽  
Author(s):  
W.G. Townson
Keyword(s):  
Lower Cambrian ◽  
Oil And Gas ◽  
Source Rocks ◽  
Petroleum Exploration ◽  
Gas Generation ◽  
Upper Proterozoic ◽  
Magnetic Basement ◽  
Complex Structural ◽  
Proterozoic Basement ◽  
The 1960S

The Officer Basin described in this paper includes four Proterozoic to Lower Palaeozoic sub-basins (Gibson, Yowalga, Lennis, Waigen) which extend in a northwest to southeast belt across 200 000 sq. km of central Western Australia. These sub-basins are bounded by Archaean to Proterozoic basement blocks and are almost entirely concealed by a veneer of Permian and Cretaceous sediments. Depth to magnetic basement locally exceeds eight kilometres.Until recently, information on the sub-surface geology was limited to shallow levels, based on the results of a petroleum exploration campaign in the 1960s and the work of State and Federal Geological Surveys. In 1980, the Shell Company of Australia was awarded three permits (46 200 sq. km) covering the Yowalga and Lennis Sub-basins. The results of 4700 km of seismic data and three deep wildcat wells, combined with gravity, aeromagnetic, Landsat, outcrop and corehole information, has led to a better understanding of the regional subsurface geology.The Lennis Sub-basin appears to contain Lower to Middle Proterozoic sediments, whereas the Yowalga Sub- basin is primarily an Upper Proterozoic to Lower Cambrian sequence which comprises a basal clastic section, a middle carbonate and evaporite sequence and an upper clastic section. Widespread Middle Cambrian basalts cap the Upper Proterozoic to Lower Cambrian prospective sequence. Late Proterozoic uplift resulted in salt- assisted gravity tectonics leading to complex structural styles, especially in the basin axis.Despite oil shows, organic matter in the oil and gas generation windows and reservoir-quality sandstones with interbedded shales, no convincing source rocks or hydrocarbon accumulations have yet been located. The area remains, however, one of the least explored basins in Australia.

Prospect Evaluation Based on Integrated Petroleum System Analysis: Block E Case Study, South-Eastern Edge of Precaspian Basin Kazakhstan

2021 ◽  
Author(s):  
Ainura Zhanserkeyeva ◽  
Akzhan Kassenov
Keyword(s):  
Vertical Migration ◽  
Oil And Gas ◽  
Source Rocks ◽  
Late Triassic ◽  
Lower Permian ◽  
Type Ii ◽  
Thermal Maturity ◽  
Type Iii ◽  
South Eastern ◽  
Oil Generation

Abstract Positive geological and geochemical prerequisites have been identified for the purpose of increasing hydrocarbon resource potential in the under-explored study area. A methodology has been developed for assessing the hydrocarbon potential and prospecting for new promising oil and gas accumulation zones using the technology of basin modeling, provided there is a lack of initial data. A high hydrocarbon source rock generative potential and the degree of thermal maturity of the Lower Permian, Mid Carboniferous and Upper Devonian strata of the south-eastern part of the Precaspian depression have been revealed. Seismostratigraphic and geodynamic analysis was carried out and the main stages of the geodynamic evolution of the study area were reconstructed based on combination of all available geological and geophysical information, recent exploration drilling results and unpublished subsurface studies. The results of thermotectonic modelling confirm the possibility of vertical migration of hydrocarbons generated in Paleozoic sediments. A revision of the previously performed interpretation of 3D seismic data has been carried out; and for the first time, intrasalt sedimentary packets of presumably Upper Permian age have been identified as independent objects, which can be potential hydrocarbon traps. For the Lower Permian deposits, type III kerogen predominates, which may be associated with an increase in collisional processes in the Late Paleozoic time and an active input of plant organic matter. For Mid Carboniferous sediments, mixed type II / III kerogen or type II kerogen prevails. Analysis of the evolution of thermal maturity indicates the unevenness of the entry of potential oil and gas source strata into the main zone of oil generation. For kerogen type III of the Lower Permian source rocks, the peak of oil generation falls on the Late Cretaceous. For predominantly carbonate and terrigenous-carbonate Middle Carboniferous source rocks the peak of generation falls on the Jurassic. The most submerged Devonian source rocks are located mainly in the zone of wet gas generation. The development of salt tectonics from the Late Triassic to the Cenozoic contributed to the vertical migration of hydrocarbons into the post-salt complex. The identified oil fields in the Upper Triassic-Jurassic stratigraphic section are mainly confined to the four-way dip structural closured above the steep flanks of salt structures.

scholarly journals New data on oil and gas potential of the Vychegda Trough

Georesursy ◽  
2020 ◽  
Vol 22 (1) ◽  
pp. 32-38
Author(s):  
Tatyana V. Karaseva ◽  
Yury A. Yakovlev ◽  
Galina L. Belyaeva ◽  
Svetlana E. Bashkova
Keyword(s):  
Oil And Gas ◽  
Geological Structure ◽  
Petroleum System ◽  
Source Rocks ◽  
Upper Permian ◽  
Hydrocarbon Potential ◽  
Petroleum Potential ◽  
Petroleum Systems ◽  
Upper Riphean ◽  
European Part Of Russia

This article is devoted to the problem of studying the petroleum potential of the underexplored territories of the European part of Russia, in particular, the Vychegda trough. Taken a new approach to assessing the hydrocarbon potential of the Vychegda trough, based on the allocation of petroleum systems, widely used abroad. Based on a comprehensive analysis of the geological structure of the deflection and geological-geochemical results, including those obtained by the authors, two potential petroleum systems – “domanic” and “riphean” – were identified. The potential domanic petroleum system dominates in the Eastern regions and is a peripheral fragment of the regional petroleum system covering the territory of the Volga-Ural and Timan-Pechora basins. The system is linked to development in the South-Eastern part of the trough and the neighbouring Solikamsk depression of bituminous domanic and domanicoid sediments as a source rock, which is confirmed by the genetic correlation of crude oils of Devonian-Carboniferous deposits of the Northern districts of Solikamsk depression with domanic biomarker. The stratigraphic range of the domanic system is upper Devonian-upper Permian; the formation time is late Devonian-Mesozoic. The potential Riphean hydrocarbon system can be identified by the fact of oil-bitumen occurrences in the Proterozoic strata and the presence of the productive source rocks in the upper Riphean. The source rocks were at oil window. The Riphean system can cover the entire territory of the Vychegda trough, and the section from the Riphean to upper Permian sediments. The time of the system formation – Riphean-Mesozoic. Due to large thickness of the Riphean sediments, even with a large loss of hydrocarbon potential, the residual potential hydrocarbon resources of the Riphean petroleum system can be very significant. Based on the research conducted, prioritized exploration studies are substantiated.

Prospectivity of the 2014 offshore acreage release areas for petroleum exploration

2014 ◽  
Vol 54 (1) ◽  
pp. 383
Author(s):  
Thomas Bernecker ◽  
Dianne Edwards ◽  
Tehani Kuske ◽  
Bridgette Lewis ◽  
Tegan Smith
Keyword(s):  
Large Scale ◽  
Oil And Gas ◽  
Gas Production ◽  
Source Rocks ◽  
Petroleum Exploration ◽  
Oil And Gas Production ◽  
Northern Margin ◽  
Petroleum Systems ◽  
Basin Scale ◽  
Northern Carnarvon Basin

The Australian Government formally releases new offshore exploration areas at the annual APPEA conference. Industry nominations provided guidance for the selection of gazettal areas, and in 2014 all 30 areas are supported by such nominations. The release areas are located across various offshore hydrocarbon provinces ranging from mature basins with ongoing oil and gas production to exploration frontiers. Work program bids are invited for two rounds closing on 2 October 2014 and 2 April 2015, while the closing date for four cash bid areas is 5 February 2015. Twenty-nine of the 2014 Release Areas are located along Australia’s northern margin within the Westralian Superbasin, which encompasses the rift-basins that extend from the Northern Carnarvon Basin to the Bonaparte Basin. Evolution during Gondwana break-up established a series of petroleum systems, many of which have been successfully explored, while others remain untapped. Only one area was nominated and approved for release on Australia’s southern margin. The 220 graticular blocks cover almost the entire Eyre Sub-basin of the Bight Basin. In the context of the recent commencement of large-scale exploration programs in the Ceduna and Duntroon sub-basins, this release area provides additional opportunities to explore an offshore frontier. Geoscience Australia’s new long-term petroleum program supports industry activities by engaging in petroleum geological studies that are aimed at the establishment of margin to basin-scale structural frameworks and comprehensive assessments of Australian source rocks underpinning all hydrocarbon prospectivity studies.

Source rock characterisation of under-explored regions of Queensland

2016 ◽  
Vol 56 (2) ◽  
pp. 580 ◽  
Author(s):  
Alison Troup ◽  
Sally Edwards
Keyword(s):  
Source Rock ◽  
Oil And Gas ◽  
Isotope Analysis ◽  
Predictive Modelling ◽  
Gas Analysis ◽  
Source Rocks ◽  
Petroleum Exploration ◽  
Pyrolysis Gas ◽  
Petroleum Systems ◽  
Rock Analysis

Historically, petroleum exploration in Queensland has focused on the Bowen-Surat and Cooper-Eromanga basins, with only cursory examination of other basins across the state. As part of the Queensland Industry Priorities Initiative, two projects (Round 1 and 2) were submitted to the Geological Survey of Queensland (GSQ) to examine the geochemical characteristics of potential petroleum source rocks throughout Queensland. The analysis conducted provides a better understanding of generative potential for petroleum, and predicts the timing, volume, composition, and physical state of hydrocarbons retained in and expelled from source rocks. It is an integral component to petroleum systems analysis used to identify the potential for undiscovered accumulations of petroleum from conventional and unconventional reservoirs. Of particular interest were the Georgina, Drummond, Eromanga, and Maryborough basins. Of these, the Georgina and Maryborough basins have known hydrocarbon shows identified through exploration drilling, though no commercial discoveries have yet been made. The Drummond Basin was targeted to identify a potential source for oil and gas shows encountered in drilling within the Galilee Basin. The Toolebuc Formation in the Eromanga Basin has been noted as having the potential for a shale oil play and this study is supporting further assessment to identify optimal areas for future exploration through predictive modelling. This report details the results from Round 1 of the study for samples taken from the Georgina Limestone and Scartwater, Ducabrook, Mount Hall, Toolebuc, and Maryborough formations, where limited analysis of source rock characteristics has historically been undertaken. Ninety-seven samples were chosen from nine wells and sent to Geos4 in Potsdam, Germany, for source rock analysis. All samples were screened for suitability of further analysis using Rock-Eval and TOC by LECO, with immature and organic-rich samples being preferentially selected for further testing. Screened samples were analysed using pyrolysis gas chromatography (n=27), thermovaporisation (n=23), bulk kinetics (n=5), compositional kinetics (n=4), late gas analysis (n=14), and biomarker and bulk isotope analysis (n=15). These results have been integrated with existing analyses to better understand the prospectivity of the under-explored basins of Queensland.

scholarly journals Sedimentology and geochemistry of Middle–Upper Permian in northwestern Turpan–Hami Basin, China: Implication for depositional environments and petroleum geology

2018 ◽  
Vol 36 (4) ◽  
pp. 910-941
Author(s):  
Jian Song ◽  
Zhidong Bao ◽  
Xingmin Zhao ◽  
Yinshan Gao ◽  
Xinmin Song ◽  
...  
Keyword(s):  
Depositional Environment ◽  
Saline Water ◽  
Depositional Environments ◽  
Source Rocks ◽  
Petroleum Exploration ◽  
Upper Permian ◽  
Late Permian ◽  
Humid Climate ◽  
Mountain Area ◽  
Volcanic Source

Studies have found that the Permian is another important stratum for petroleum exploration except the Jurassic coal measures within Turpan–Hami Basin recently. However, the knowledge of the depositional environments and its petroleum geological significances during the Middle–Late Permian is still limited. Based on the analysis about the sedimentological features of the outcrop and the geochemical characteristics of mudstones from the Middle Permian Taerlang Formation and Upper Permian Quanzijie Formation in the Taoshuyuanzi profile, northwest Turpan–Hami Basin, this paper makes a detailed discussion on the Middle–Late Permian paleoenvironment and its petroleum geological significances. The Middle–Upper Permian delta–lacustrine depositional system was characterized by complex vertical lithofacies assemblages, which were primarily influenced by tectonism and frequent lake-level variations in this area. The Taerlang Formation showed a significant lake transgression trend, whereas the regressive trend of the Quanzijie Formation was relatively weaker. The provenance of Taerlang and Quanzijie Formations was derived from the rift shoulder (Bogda Mountain area now) to the north and might be composed of a mixture of andesite and felsic volcanic source rocks. The Lower Taerlang Formation was deposited in a relatively hot–dry climate, whereas the Upper Taerlang and Quanzijie Formations were deposited in a relatively humid climate. During the Middle–Late Permian, this area belonged to an overall semi-saline water depositional environment. The paleosalinity values showed stepwise decreases from the Lower Taerlang Formation to the Upper Quanzijie Formation, which was influenced by the changes of paleoclimate in this region. During the Middle–Late Permian, the study area was in an overall anoxic depositional environment. The paleoenvironment with humid climate, lower paleosalinity, anoxic condition, and semi-deep to deep water during the deposition of the Upper Taerlang Formation was suitable for the accumulation of mudstones with higher TOC values.

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