Organic-geochemistry characterization of the Paleogene to Neogene source rocks in the Sayhut subbasin, Gulf of Aden Basin, with emphasis on organic-matter input and petroleum-generation potential

AbstractDuring Middle Devonian time a thick succession of organic-rich, mainly lacustrine flagstones developed within the Orcadian Basin. These petroleum source rocks crop out in northern Scotland. Nineteen samples were studied using organic petrology, palynology and organic geochemistry in order to characterize kerogen type, depositional environment, thermal maturity and petroleum generation potential. Corg, carbonate and sulphur content as well as hydrogen index (HI) values are quite variable (e.g. HI from 79 to 744 mg HC/g Corg). Based on biomarker data, organic material mainly originates from aquatic organic matter deposited under lacustrine conditions with oxygen-depleted, but not permanently anoxic, bottom waters. Petrography reveals small quantities of vitrinite particles, indicating minor input of terrestrial material. This is supported by biomarker data and the palynofacies, which is characterized by a high amount of oil-prone amorphous organic matter (AOM) and generally few miospores. Maturity of the succession studied in Caithness and Orkney is between immature and oil mature. One-dimensional basin modelling shows that a significant remaining hydrocarbon generation potential exists within the Middle Devonian succession. In contrast to the low hydrocarbon generation in the onshore area, offshore oil generation was significant, especially after deposition of thick Upper Jurassic – Upper Cretaceous sediments. At the end of Cretaceous time, hydrocarbon generation ceased due to uplift. The contribution to known oil fields from the Devonian flagstones is a realistic scenario, including a contribution to the Beatrice oil field in the south of the modelled area.

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Source Rocks Characterization Of Agbada And Akata Formations In The Niger Delta, Nigeria

European Journal of Environment and Earth Sciences ◽

10.24018/ejgeo.2020.1.4.38 ◽

2020 ◽

Vol 1 (4) ◽

Author(s):

Koffi Eugene Kouadio ◽

Selegha Abrakasa ◽

Sunday S. Ikiensikimama ◽

Takyi Botwe

Keyword(s):

Organic Matter ◽

Niger Delta ◽

Early Stage ◽

Source Rocks ◽

Thermal Maturity ◽

Petroleum Generation ◽

Niger Delta Basin ◽

Rock Eval ◽

Organic Matter Abundance

The geochemical analysis was performed on twelve (12) core samples from 6 wells of different formations (Akata, Agbada, and Akata/Agbada) of the onshore Niger Delta Basin. The study was essentially based on the results of the Rock-Eval 6 Pyrolysis to evaluate organic matter abundance, quality, and thermal maturity. The Total Organic Carbon (TOC) varies between 0.6 and 3.06 wt% and the Hydrogen Index (IH) of the studied samples ranges from 38 to 202 mgHC/g TOC, indicating predominantly Type III (gas prone) and mixed type II/III (gas and oil-prone) kerogen. This suggests terrigenous and a mixture of marine and terrigenous organic matter deposited in a paralic marine setting. The organic matter is immature to early mature according to the thermal maturity parameter (414<Tmax<432). The well Isan 9 from Agbada (6760 ft) and Agbada/Akata (8680 ft) shows petroleum generation potential of fair (2,5 < S2 < 5 mg HC/g rock) to good (5 < S2 < 10 mgHC/g rock) and poor for the other wells. The maturation of the kerogen indicates a very early stage of maturation (Tmax= 432°C). The results indicate that the shales from Agbada and the transition zone between the upper and lower parts of the Akata Shales are more shaly and perhaps the more mature part of the Agbada formation can be the potential source rocks of Niger Delta Basin.

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Petrography and Organic Geochemistry Characterizations of Lower Paleozoic Organic-Rich Shale in the Northwestern Upper Yangtze Plate: Niutitang Formation and Longmaxi Formation, Dabashan Foreland Belt

Minerals ◽

10.3390/min8100439 ◽

2018 ◽

Vol 8 (10) ◽

pp. 439 ◽

Cited By ~ 1

Author(s):

Delu Li ◽

Rongxi Li ◽

Di Zhao ◽

Feng Xu

Keyword(s):

Gas Chromatography ◽

Organic Matter ◽

Organic Geochemistry ◽

Source Rocks ◽

Gas Chromatography Mass Spectrometry ◽

Mature Stage ◽

Type I ◽

Lower Paleozoic ◽

Longmaxi Formation ◽

Niutitang Formation

Measurements of total organic carbon, Rock-Eval pyrolysis, X-ray diffraction, scanning electron microscope, maceral examination, gas chromatography, and gas chromatography-mass spectrometry were conducted on the organic-rich shale of Lower Paleozoic Niutitang Formation and Longmaxi Formation in Dabashan foreland belt to discuss the organic matter characteristic, organic matter origin, redox condition, and salinity. The results indicate that the Niutiang Formation and Longmaxi Formation organic-rich shale are good and very good source rocks with Type I kerogen. Both of the shales have reached mature stage for generating gas. Biomarker analyses indicate that the organic matter origin of Niutitang Formation and Longmaxi Formation organic-rich shale are all derived from the lower bacteria and algae, and the organic matter are all suffered different biodegradation degrees. During Niutitang Formation and Longmaxi Formation period, the redox conditions are both anoxic with no stratification and the sedimentary water is normal marine water.

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Geochemical characterization of hydrocarbon source rocks of the Triassic-Jurassic time interval in the Mandawa basin, southern Tanzania: Implications for petroleum generation potential

South African Journal of Geology ◽

10.25131/sajg.123.0037 ◽

2020 ◽

Vol 123 (4) ◽

pp. 587-596

Author(s):

A. Emanuel ◽

C.H. Kasanzu ◽

M. Kagya

Keyword(s):

Source Rocks ◽

Geochemical Data ◽

Time Interval ◽

Type I ◽

Hydrocarbon Generation ◽

Type Ii ◽

Geochemical Characterization ◽

Type Iii ◽

Petroleum Generation

Abstract Triassic to mid-Jurassic core samples of the Mandawa basin, southern Tanzania (western coast of the Indian Ocean), were geochemically analyzed in order to constrain source rock potentials and petroleum generation prospects of different stratigraphic formations within the coastal basin complex. The samples were collected from the Mihambia, Mbuo and Nondwa Formations in the basin. Geochemical characterization of source rocks intersected in exploration wells drilled between 503 to 4042 m below surface yielded highly variable organic matter contents (TOC) rated between fair and very good potential source rocks (0.5 to 8.7 wt%; mean ca. 2.3 wt%). Based on bulk geochemical data obtained in this study, the Mandawa source rocks are mainly Type I, Type II, Type III, mixed Types II/III and Type IV kerogens, with a predominance of Type II, Type III and mixed Type II/III. Based on pyrolysis data (Tmax 417 to 473oC; PI = 0.02 to 0.47; highly variable HI = 13 to 1 000 mg/gTOC; OI = 16 to 225 mg/g; and VR values of between 0.24 to 0.95% Ro) we suggest that the Triassic Mbuo Formation and possibly the mid-Jurassic Mihambia Formation have a higher potential for hydrocarbon generation than the Nondwa Formation as they are relatively thermally mature.

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Characterization of the source rocks of a paleo-petroleum system (Cameros Basin) based on organic matter petrology and geochemical analyses

Marine and Petroleum Geology ◽

10.1016/j.marpetgeo.2016.01.002 ◽

2016 ◽

Vol 71 ◽

pp. 271-287 ◽

Cited By ~ 5

Author(s):

Silvia Omodeo-Salé ◽

Isabel Suárez-Ruiz ◽

José Arribas ◽

Ramón Mas ◽

Luis Martínez ◽

...

Keyword(s):

Organic Matter ◽

Petroleum System ◽

Source Rocks ◽

Cameros Basin ◽

Geochemical Analyses

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Organic Geochemistry Of The Middle To Upper Jurassic Source Rocks Succession In Balad-1 Well, Balad Oil Field, Central Iraq

Bulletin of the Geological Society of Malaysia ◽

10.7186/bgsm71202111 ◽

2021 ◽

Vol 71 ◽

pp. 125-138

Author(s):

Fawzi M.O. Albeyati ◽

◽

Rzger A. Abdula ◽

Rushdy S. Othman ◽

Keyword(s):

Organic Matter ◽

Organic Geochemistry ◽

Equilibrium Phase ◽

Organic Matter Content ◽

Upper Jurassic ◽

Matter Content ◽

Oil Field ◽

Source Rocks ◽

Content Type ◽

Depositional Setting

Thirty four cuttings samples from the Jurassic rock succession in well Balad-1 in the Balad Oil Field, Central Iraq have been collected. Using various organic geochemical techniques, the organic matter’s quantity, quality, maturity, and their source rock’s depositional setting were determined. The samples were evaluated to determine the amount of their organic matter content, type of organic matter, δ13C carbon isotopes abundance for both saturated and aromatic, and molecular properties. The results of organic geochemistry analysis show that Sargelu, Gotnia, and Chia Gara formations contain fair to decent amounts of organic matter. Naokelekan Formation encompasses fair to excellent organic matter, while Najmah Formation comprises very high to exceptional organic matter. The analyzed samples revealed the existence of kerogen types III and II/III mainly within oil window. Thermal maturity related biomarkers are in a good agreement with Rock-Eval parameters, but did not reach equilibrium phase. Source related biomarkers show that these rock units rich in organic matter were mainly deposited in an anoxic marine depositional setting which consists of carbonate influenced by terrestrial input.

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Paleoenvironment and organic matter enrichment of the Carboniferous volcanic-related source rocks in the Malang Sag, Santanghu Basin, NW China

Petroleum Science ◽

10.1007/s12182-020-00514-1 ◽

2020 ◽

Author(s):

Tian-Jun Li ◽

Zhi-Long Huang ◽

Xuan Chen ◽

Xin-Ning Li ◽

Jun-Tian Liu

Keyword(s):

Organic Matter ◽

Mineral Content ◽

Hydrothermal Activity ◽

Source Rocks ◽

Mature Stage ◽

Terrigenous Organic Matter ◽

Oil Generation ◽

Generation Capacity ◽

Hydrothermal Activities ◽

Organic Matter Input

AbstractVolcanic activity was quite frequent during the deposition of the Late Carboniferous Ha’erjiawu Formation in the Santanghu Basin. The petrology and organic and inorganic geochemical indicators were used to investigate hydrocarbon potential, paleoenvironmental conditions and organic matter enrichment of the mudstones. The results show that the oil generation capacity of the Ha’erjiawu Formation mudstones, which has abundant oil-prone organic matter (Type II kerogen with hydrogen index values mainly ranging from 250 to 550 mg HC/g TOC) in mature stage (Tmax values mainly ranging from 435 to 450 °C), is considerable. The Ha’erjiawu Formation was deposited in a dysoxic, freshwater-mildly brackish, and warm-humid environment. During its deposition, the Ha’erjiawu Formation received hydrothermal inputs. The volcanic hydrothermal activities played an important role in the organic matter enrichment. In addition, the total organic carbon (TOC) is significantly positively correlated with the felsic mineral content, but it is negatively correlated with the carbonate mineral content and C27/C29 ratios, indicating that terrigenous organic matter input also contributed to the primary productivity in the surface water. Therefore, the formation of the high-quality source rocks in the Ha’erjiawu Formation was jointly affected by the hydrothermal activity and the terrigenous organic matter input.

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The CHNs of organic geochemistry: characterization of molecularly uncharacterized non-living organic matter

Marine Chemistry ◽

10.1016/j.marchem.2004.06.014 ◽

2004 ◽

Vol 92 (1-4) ◽

pp. 5-8 ◽

Cited By ~ 7

Author(s):

Patrick G. Hatcher

Keyword(s):

Organic Matter ◽

Organic Geochemistry

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Origins of hydrocarbons in the Geneva Basin: insights from oil, gas and source rock organic geochemistry

Swiss Journal of Geosciences ◽

10.1186/s00015-021-00388-4 ◽

2021 ◽

Vol 114 (1) ◽

Author(s):

Damien Do Couto ◽

Sylvain Garel ◽

Andrea Moscariello ◽

Samer Bou Daher ◽

Ralf Littke ◽

...

Keyword(s):

Organic Matter ◽

Source Rock ◽

Oil And Gas ◽

Organic Geochemistry ◽

Source Rocks ◽

Type Ii ◽

Dominant Type ◽

Type Iii ◽

North Alpine Foreland Basin ◽

Migration Pathways

AbstractAn extensive subsurface investigation evaluating the geothermal energy resources and underground thermal energy storage potential is being carried out in the southwestern part of the Swiss Molasse Basin around the Geneva Canton. Among this process, the evaluation of the petroleum source-rock type and potential is an important step to understand the petroleum system responsible of some oil and gas shows at surface and subsurface. This study provides a first appraisal of the risk to encounter possible undesired occurrence of hydrocarbons in the subsurface of the Geneva Basin. Upon the numerous source-rocks mentioned in the petroleum systems of the North Alpine Foreland Basin, the marine Type II Toarcian shales (Lias) and the terrigenous Type III Carboniferous coals and shales have been sampled from wells and characterized with Rock–Eval pyrolysis and GC–MS analysis. The Toarcian shales (known as the Posidonia shales) are showing a dominant Type II organic matter composition with a Type III component in the Jura region and the south of the basin. Its thermal maturity (~ 0.7 VRr%) shows that this source-rock currently generates hydrocarbons at depth. The Carboniferous coals and shales show a dominant Type III organic matter with slight marine to lacustrine component, in the wet gas window below the Geneva Basin. Two bitumen samples retrieved at surface (Roulave stream) and in a shallow borehole (Satigny) are heavily biodegraded. Relative abundance of regular steranes of the Roulave bitumen indicates an origin from a marine Type II organic matter. The source of the Satigny bitumen is supposedly the same even though a deeper source-rock, such as the lacustrine Permian shales expelling oil in the Jura region, can’t be discarded. The oil-prone Toarcian shales in the oil window are the most likely source of this bitumen. A gas pocket encountered in the shallow well of Satigny (Geneva Canton), was investigated for molecular and stable isotopic gas composition. The analyses indicated that the gas is made of a mixture of microbial (very low δ13C1) and thermogenic gas. The isotopic composition of ethane and propane suggests a thermogenic origin from an overmature Type II source-rock (> 1.6 VRr%) or from a terrigenous Type III source at a maturity of ~ 1.2 VRr%. The Carboniferous seems to be the only source-rock satisfying these constraints at depth. The petroleum potential of the marine Toarcian shales below the Geneva Basin remains nevertheless limited given the limited thickness of the source-rock across the area and does not pose a high risk for geothermal exploration. A higher risk is assigned to Permian and Carboniferous source-rocks at depth where they reached gas window maturity and generated large amount of gas below sealing Triassic evaporites. The large amount of faults and fractures cross-cutting the entire stratigraphic succession in the basin certainly serve as preferential migration pathways for gas, explaining its presence in shallow stratigraphic levels such as at Satigny.

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The origins of paraffinic oils collected from oilfields in the western Siberian Basin, Russia: implications from geochemical and physical characteristics

Journal of Petroleum Exploration and Production Technology ◽

10.1007/s13202-021-01325-9 ◽

2021 ◽

Author(s):

Mohammed Hail Hakimi ◽

Shadi A. Saeed ◽

Ameen A. Al-Muntaser ◽

Mikhail A. Varfolomeev ◽

Richard Djimasbe ◽

...

Keyword(s):

Organic Matter ◽

Sulfur Content ◽

Source Rock ◽

Environmental Conditions ◽

Saturated Hydrocarbon ◽

Source Rocks ◽

Terrestrial Organic Matter ◽

Low Sulfur Content ◽

Low Sulfur ◽

Organic Matter Input

AbstractFour oil samples were collected from oilfields in the western Siberian Basin, and analyzed using conventional geochemical and physical methods. The results of this study were used to evaluate the oil samples, focusing on the characteristics of their source rocks, including the origin of organic matter input; redox depositional conditions and degree of thermal maturity of their probable source rock were studied. The obtained SARA results show that the examined oils are paraffinic oils owing to their high saturated hydrocarbon fraction values of greater than 70% volume. The observed API gravity values (23.55° to 32.57°) and low sulfur content of less than 0.25% wt indicate that the examined oils are sweet oils and were generated from source rock containing Type-II, with low sulfur content. The low sulfur content combined with the vanadium (V) and nickel (Ni) ratios indicates that the examined oils were scoured from a mixture of aquatic and terrestrial organic matter, depositing under generally suboxic environmental conditions. The n-alkane and isoprenoid distributions, with their ratios and parameters further suggest that the examined oil samples were generated from source rock containing a mixed organic matter input and deposited under suboxic to relatively oxic environmental conditions. Bulk compositions and distributions of n-alkane and isoprenoid indicate that the oil samples were generated from mature source rock.

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