scholarly journals Paleozoic Stratigraphy and Petroleum Systems of the Western and Southwestern Deserts of Iraq

GeoArabia ◽  
1998 ◽  
Vol 3 (2) ◽  
pp. 229-248 ◽  
Author(s):  
Adnan A.M. Aqrawi
Keyword(s):  
Saudi Arabia ◽  
Black Shales ◽  
Source Rocks ◽  
Western Desert ◽  
Upper Permian ◽  
Published Data ◽  
Lower Silurian ◽  
Deep Wells ◽  
Thrust Zone ◽  
Western Desert Of Iraq

ABSTRACT A stratigraphic scheme for the Paleozoic of the Southwestern Desert of Iraq is proposed based upon the review of recently published data from several deep wells in the western part of the country and from outcrops in other regions in Iraq. The main formations are described in terms of facies distribution, probable age, regional thickness, and correlations with the well-reported Paleozoic successions of the adjacent countries (e.g. Jordan and Saudi Arabia), as well as with the Thrust Zone of North Iraq. The Paleozoic depositional and tectonic evolution of the Western and Southwestern Deserts of Iraq, particularly during Cambrian, Ordovician and Silurian, shows marked similarity to those of eastern Jordan and northern Saudi Arabia. However, local lithological variations, which are due to Late Paleozoic Hercynian tectonics, characterize the Upper Paleozoic sequences. The Lower Silurian marine “hot” shale, 65 meters thick in the Akkas-1 well in the Western Desert, is believed to be the main Paleozoic source rock in the Western and Southwestern Deserts. Additional potential source rocks in this region could be the black shales of the Ordovician Khabour Formation, the Upper Devonian to Lower Carboniferous Ora Shale Formation, and the lower shaly beds of the Upper Permian Chia Zairi Formation. The main target reservoirs are of Ordovician, Silurian, Carboniferous and Permian ages. Similar reservoirs have recently been reported for the Western Desert of Iraq, eastern Jordan and northern Saudi Arabia. In addition, two main regional seals (Lower Silurian shales and Permian evaporites) of northeastern Arabia extend over most of the Southwestern Desert, together with several other local seals. These considerations render the unexplored Paleozoic Southwestern Desert of Iraq prospective.

scholarly journals BIOSTRATIGRAPHIC CORRELATION OF PALEOZOIC ROCKS IN NORTHERN AND WESTREN IRAQ

2020 ◽  
Vol 8 (3) ◽  
pp. 315-323
Author(s):  
Falah H. Khalaf Al-jubori ◽  
Akram K. Youkhana ◽  
Srood F. Naqshabandi ◽  
Dyana A. Bayz
Keyword(s):  
Regional Distribution ◽  
Source Rocks ◽  
Western Desert ◽  
Upper Permian ◽  
Upper Ordovician ◽  
Northern Iraq ◽  
Clastic Rocks ◽  
Western Desert Of Iraq ◽  
Paleozoic Rocks ◽  
Stratigraphic Succession

The Paleozoic rocks outcropped in northern Iraq (Ora, Chia Zairi section) are biostratigraphically investigated for their microfossils content. Benthonic foraminifera and algal genera characterize the upper part of the section while palynomorphs (Miospores & Acritarchs) dominated the lower part the section which is consist of clastic sediments. The study also include the stratigraphic succession of the section and its correlation to the subsurface sections penetrated in oil and  water wells drilled in the western desert of Iraq in order to determine the regional distribution of the economically important formations, either  as reservoir or as source  rocks for hydrocarbons. Index palynomorphs including many types of Acritarch genera are identified in the Khabour Formation indicate lower Ordovician time (Tremadocian? Arenigian –Llanvirnian: age) The Perispik Formation has been found barren of any type of microfossils and is composed of red clastic rocks. Pollen and Spores are recorded from the "Ore Group"  (Kaista, Ora and Harur Formations )  indicate that these rocks are of Upper Devonian – Lower Carboniferous  (Famennian – Tournaisian age ) .A Large number of  foraminifera and Algal genera are identified in the Chiazairi rocks,these genera and species are indicated the Upper Permian rocks of Thuringian age. The stratigraphic   succession of the Paleozoic section studied in northern Iraq indicate that there is a stratigraphic break represents by missing of the Ga'ara Formation (late Carboniferous –early Permian) and Akkas Formation (Silurian) and the upper part of the Khabour Formation (Upper Ordovician).

scholarly journals Biomarkers and C and S Isotopes of the Permian to Triassic Solid Bitumen and Its Potential Source Rocks in NE Sichuan Basin

Geofluids ◽  
2017 ◽  
Vol 2017 ◽  
pp. 1-14 ◽  
Author(s):  
Chunfang Cai ◽  
Chenlu Xu ◽  
Wenxiang He ◽  
Chunming Zhang ◽  
Hongxia Li
Keyword(s):  
Source Rock ◽  
Vitrinite Reflectance ◽  
Lower Triassic ◽  
Source Rocks ◽  
Upper Permian ◽  
Solid Bitumen ◽  
Lower Silurian ◽  
High Maturity ◽  
Gas Fields ◽  
Extractable Organic Matter

The potential parent source rocks except from Upper Permian Dalong Formation (P3d) for Upper Permian and Lower Triassic solid bitumen show high maturity to overmaturity with equivalent vitrinite reflectance (ERo) from 1.7% to 3.1% but have extractable organic matter likely not contaminated by younger source rocks. P3d source rocks were deposited under euxinic environments as indicated by the pyrite δ34S values as light as -34.5‰ and distribution of aryl isoprenoids, which were also detected from the Lower Silurian (S1l) source rock and the solid bitumen in the gas fields in the west not in the east. All the solid bitumen not altered by thermochemical sulfate reduction (TSR) has δ13C and δ34S values similar to part of the P3l kerogens and within the S1l kerogens. Thus, the eastern solid bitumen may have been derived from the P3l kerogens, and the western solid bitumen was likely to have precracking oils from P3l kerogens mixed with the S1l or P3d kerogens. This case-study tentatively shows that δ13C and δ34S values along with biomarkers have the potential to be used for the purpose of solid bitumen and source rock correlation in a rapidly buried basin, although further work should be done to confirm it.

Thermal maturity and burial history of Paleozoic rocks in western Newfoundland

1998 ◽  
Vol 35 (11) ◽  
pp. 1307-1322 ◽  
Author(s):  
S Henry Williams ◽  
Elliott T Burden ◽  
P K Mukhopadhyay
Keyword(s):  
Vitrinite Reflectance ◽  
Point Group ◽  
Black Shales ◽  
Source Rocks ◽  
Head Group ◽  
Published Data ◽  
Burial History ◽  
Upper Ordovician ◽  
Middle Ordovician ◽  
Paleozoic Rocks

Palynomorphs and graptolites from Paleozoic strata in western Newfoundland are examined and correlated with previously published data to identify fossils which are characteristic of proven and suspected source rocks. Measurements of colour alteration of acritarchs and spores (acritarch alteration index and thermal alteration index), random graptolite reflectance, and vitrinite reflectance are applied to determine regional thermal maturation and burial history. General trends of increasing maturity from south to north along the Northen Peninsula and from west to east across the Port au Port Peninsula are observed. Within these general trends, a more detailed distribution of thermal maturities can be recognized. In the south, Upper Ordovician rocks of the Long Point Group, western Port au Port Peninsula, exhibit the lowest maturity values found in western Newfoundland and are considered immature or marginally mature. Middle Ordovician rocks of the Goose Tickle and Table Head groups and the Lower Ordovician St. George Group are marginally mature. Cambrian strata on the Port au Port Peninsula are mature. Maturation levels increase to the east; Goose Tickle Group black shales in the vicinity of Black Cove, east of Port au Port, are mature. Equivalent sediments extending for another 15-20 km to the east lie within the oil window. Beyond that area, the equivalent rocks are overmature. The best potential source rocks belonging to the allochthonous Cow Head Group contain abundant acritarchs and Gloeocapsamorpha sp. These rocks are marginally mature to mature within Gros Morne National Park; maturation levels increase farther north (e.g., Parsons Pond), becoming overmature somewhere south of Port au Choix. It is concluded that neither the allochthonous Ordovician rocks presently exposed in Gros Morne nor the autochthonous strata exposed on the Port au Port Peninsula have ever been covered by significant thicknesses of overburden (probably 3 km or less), either in the form of structural slices or other sedimentary units since their original deposition.

Hydrothermal activity in the Upper Permian Ravnefjeld Formation of central East Greenland – a study of sulphide morphotypes

1998 ◽  
pp. 81-87
Author(s):  
Jesper Kresten Nielsen ◽  
Mikael Pedersen
Keyword(s):  
Base Metal ◽  
Early Period ◽  
Sedimentary Basins ◽  
Hydrothermal Activity ◽  
Source Rocks ◽  
Upper Permian ◽  
Thermal Activity ◽  
East Greenland ◽  
The North ◽  
Alum Shale

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article, for example: Kresten Nielsen, J., & Pedersen, M. (1998). Hydrothermal activity in the Upper Permian Ravnefjeld Formation of central East Greenland – a study of sulphide morphotypes. Geology of Greenland Survey Bulletin, 180, 81-87. https://doi.org/10.34194/ggub.v180.5090 _______________ Bituminous shales of the Ravnefjeld Formation were deposited in the subsiding East Greenland basin during the Upper Permian. The shales are exposed from Jameson Land in the south (71°N; Fig. 1) to Clavering Ø in the north (74°20′N) and have attracted considerable attention due to their high potential as hydrocarbon source rocks (Piasecki & Stemmerik 1991; Scholle et al. 1991; Christiansen et al. 1992, 1993a, b). Furthermore, enrichment of lead, zinc and copper has been known in the Ravnefjeld Formation on Wegener Halvø since 1968 (Lehnert-Thiel 1968; Fig. 1). This mineralisation was assumed to be of primary or early diagenetic origin due to similarities with the central European Kupferschiefer (Harpøth et al. 1986). Later studies, however, suggested base metal mineralisation in the immediately underlying carbonate reefs to be Tertiary in age (Stemmerik 1991). Due to geographical coincidence between the two types of mineralisation, a common history is a likely assumption, but a timing paradox exists. A part of the TUPOLAR project on the ‘Resources of the sedimentary basins of North and East Greenland’ has been dedicated to re-investigation of the mineralisation in the Ravnefjeld Formation in order to determine the genesis of the mineralisation and whether or not primary or early diagenetic base metal enrichment has taken place on Wegener Halvø, possibly in relation to an early period of hydrothermal activity. One approach to this is to study the various sulphides in the Ravnefjeld Formation; this is carried out in close co-operation with a current Ph.D. project at the University of Copenhagen, Denmark. Diagenetically formed pyrite is a common constituent of marine shales and the study of pyrite morphotypes has previously been successful from thermalli immature parts of elucidating depositional environment and thermal effects in the Alum Shale Formation of Scandinavia (Nielsen 1996; Nielsen et al. 1998). The present paper describes the preliminary results of a similar study on pyrite from thermally immature parts of the Ravnefjeld Formation which, combined with the study of textures of base metal sulphides in the Wegener Halvø area (Fig. 1), may provide an important step in the evaluation of the presence or absence of early thermal activity on (or below) the Upper Permian sea floor.

Sequence stratigraphy of source and reservoir rocks in the Upper Permian and Jurassic of Jameson Land, East Greenland

1998 ◽  
pp. 43-54 ◽  
Author(s):  
Lars Stemmerik ◽  
Gregers Dam ◽  
Nanna Noe-Nygaard ◽  
Stefan Piasecki ◽  
Finn Surlyk
Keyword(s):  
Sequence Stratigraphy ◽  
Middle Jurassic ◽  
Sedimentary Basins ◽  
Upper Jurassic ◽  
Oil Field ◽  
Source Rocks ◽  
Upper Permian ◽  
Shallow Marine ◽  
East Greenland ◽  
Reservoir Rocks

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article, for example: Stemmerik, L., Dam, G., Noe-Nygaard, N., Piasecki, S., & Surlyk, F. (1998). Sequence stratigraphy of source and reservoir rocks in the Upper Permian and Jurassic of Jameson Land, East Greenland. Geology of Greenland Survey Bulletin, 180, 43-54. https://doi.org/10.34194/ggub.v180.5085 _______________ Approximately half of the hydrocarbons discovered in the North Atlantic petroleum provinces are found in sandstones of latest Triassic – Jurassic age with the Middle Jurassic Brent Group, and its correlatives, being the economically most important reservoir unit accounting for approximately 25% of the reserves. Hydrocarbons in these reservoirs are generated mainly from the Upper Jurassic Kimmeridge Clay and its correlatives with additional contributions from Middle Jurassic coal, Lower Jurassic marine shales and Devonian lacustrine shales. Equivalents to these deeply buried rocks crop out in the well-exposed sedimentary basins of East Greenland where more detailed studies are possible and these basins are frequently used for analogue studies (Fig. 1). Investigations in East Greenland have documented four major organic-rich shale units which are potential source rocks for hydrocarbons. They include marine shales of the Upper Permian Ravnefjeld Formation (Fig. 2), the Middle Jurassic Sortehat Formation and the Upper Jurassic Hareelv Formation (Fig. 4) and lacustrine shales of the uppermost Triassic – lowermost Jurassic Kap Stewart Group (Fig. 3; Surlyk et al. 1986b; Dam & Christiansen 1990; Christiansen et al. 1992, 1993; Dam et al. 1995; Krabbe 1996). Potential reservoir units include Upper Permian shallow marine platform and build-up carbonates of the Wegener Halvø Formation, lacustrine sandstones of the Rhaetian–Sinemurian Kap Stewart Group and marine sandstones of the Pliensbachian–Aalenian Neill Klinter Group, the Upper Bajocian – Callovian Pelion Formation and Upper Oxfordian – Kimmeridgian Hareelv Formation (Figs 2–4; Christiansen et al. 1992). The Jurassic sandstones of Jameson Land are well known as excellent analogues for hydrocarbon reservoirs in the northern North Sea and offshore mid-Norway. The best documented examples are the turbidite sands of the Hareelv Formation as an analogue for the Magnus oil field and the many Paleogene oil and gas fields, the shallow marine Pelion Formation as an analogue for the Brent Group in the Viking Graben and correlative Garn Group of the Norwegian Shelf, the Neill Klinter Group as an analogue for the Tilje, Ror, Ile and Not Formations and the Kap Stewart Group for the Åre Formation (Surlyk 1987, 1991; Dam & Surlyk 1995; Dam et al. 1995; Surlyk & Noe-Nygaard 1995; Engkilde & Surlyk in press). The presence of pre-Late Jurassic source rocks in Jameson Land suggests the presence of correlative source rocks offshore mid-Norway where the Upper Jurassic source rocks are not sufficiently deeply buried to generate hydrocarbons. The Upper Permian Ravnefjeld Formation in particular provides a useful source rock analogue both there and in more distant areas such as the Barents Sea. The present paper is a summary of a research project supported by the Danish Ministry of Environment and Energy (Piasecki et al. 1994). The aim of the project is to improve our understanding of the distribution of source and reservoir rocks by the application of sequence stratigraphy to the basin analysis. We have focused on the Upper Permian and uppermost Triassic– Jurassic successions where the presence of source and reservoir rocks are well documented from previous studies. Field work during the summer of 1993 included biostratigraphic, sedimentological and sequence stratigraphic studies of selected time slices and was supplemented by drilling of 11 shallow cores (Piasecki et al. 1994). The results so far arising from this work are collected in Piasecki et al. (1997), and the present summary highlights the petroleum-related implications.

scholarly journals The Study of Uranium Accumulation in Marine Bottom Sediments: Effect of Redox Conditions at the Time of Sedimentation

Geosciences ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 332
Author(s):  
Nadezhda Khaustova ◽  
Yulia Tikhomirova ◽  
Svetlana Korost ◽  
Elena Poludetkina ◽  
Andrey Voropaev ◽  
...  
Keyword(s):  
Bottom Sediments ◽  
White Sea ◽  
Uranium Content ◽  
Black Shales ◽  
Redox Conditions ◽  
Source Rocks ◽  
Shelf Zone ◽  
The Black Sea ◽  
The White Sea ◽  
Run Off

To evaluate the effect of redox conditions at the sedimentation stage on uranium content and U/TOC ratio in marine source rocks, we analyzed the accumulation of uranium in modern marine bottom sediments formed in different redox conditions. The behavior of uranium from bottom sediments formed in oxidizing and sub-oxidizing settings has been studied on the sediments of the Upper Pleistocene–Holocene age accumulated in the coastal area of the White Sea (Kandalaksha Gulf). We studied the content of uranium, Eh, pH, TOC, C, H, N, and S element and isotope compositions and other parameters in two sampled columns of bottom sediments at a depth of 0–2.5 m. The composition of sediments was typical for the shelf zone where marine genesis mixes with the continental run-off. The upper layer of sediments (0–50 cm) were characterized by oxidizing conditions (Eh ~ 400 mV); with the increase in depth, redox conditions changed from oxidizing to reducing (0 ÷ 200 mV). The uranium concentration in the upper layer was 1–1.5 ppm, U/TOC ratio varied in the range of 0.8–1.1 ppmU/%TOC. The uranium content and U/TOC ratio increased up to the values of 2.6 ppm and 1.4 ppmU/%TOC at a depth of 0.5−2.5 m, respectively, but the general content of uranium in the studied environment was close to the values characterizing continental run-off. The results obtained for the White Sea sediments were compared with the sediment of the Black Sea, formed in the anoxic conditions of hydrogen sulfide contamination. In these conditions, the uranium content varied from 10 to 20 ppm. The obtained data were interpreted using thermodynamic modeling of the uranium forms in the seawater at different pH and Eh. This study demonstrated that the change of redox conditions from oxidizing to reducing leads to increased uranium content due to a decrease in uranium’s solubility in water. These results show that oxidation–reduction potential could be one of the most important factors controlling uranium content in black shales formed in the marine environment.

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.

scholarly journals Minimizing the Impacts of Desertification in an Arid Region: A Case Study of the West Desert of Iraq

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Khamis Naba Sayl ◽  
Sadeq Oleiwi Sulaiman ◽  
Ammar Hatem Kamel ◽  
Nur Shazwani Muhammad ◽  
Jazuri Abdullah ◽  
...  
Keyword(s):  
Land Degradation ◽  
Vegetation Index ◽  
Rainwater Harvesting ◽  
Large Change ◽  
Cost Effective ◽  
Western Desert ◽  
Gis Environment ◽  
Small Change ◽  
Western Desert Of Iraq ◽  
Suitable Land

Currently, desertification is a major problem in the western desert of Iraq. The harsh nature, remoteness, and size of the desert make it difficult and expensive to monitor and mitigate desertification. Therefore, this study proposed a comprehensive and cost-effective method, via the integration of geographic information systems (GISs) and remote sensing (RS) techniques to estimate the potential risk of desertification, to identify the most vulnerable areas and determine the most appropriate sites for rainwater conservation. Two indices, namely, the Normalized Differential Vegetation Index (NDVI) and Land Degradation Index (LDI), were used for a cadastral assessment of land degradation. The findings of the combined rainwater harvesting appropriateness map, and the maps of NDVI and LDI changes found that 65% of highly suitable land for rainwater harvesting lies in the large change and 35% lies in the small change of NDVI, and 85% of highly suitable land lies in areas with a moderate change and 12% lies in strong change of LDI. The adoption of the weighted linear combination (WLC) and Boolean methods within the GIS environment, and the analysis of NDVI with LDI changes can allow hydrologists, decision-makers, and planners to quickly determine and minimize the risk of desertification and to prioritize the determination of suitable sites for rainwater harvesting.

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