A Late Triassic gravity flow depositional system in the southern Ordos Basin

Yang, Renchao; He, Zhiliang; Qiu, Guiqiang; Jin, Zhijun; Sun, Dongsheng; Jin, Xiaohui

doi:10.1016/s1876-3804(14)60086-0

Cited by 74 publications

(30 citation statements)

References 12 publications

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“…Thus, this facies with weak normal grading and small traction structure is generally observed above facies B and facies C and could be a criterion for identify sandy debris flow of different stages. This phenomenon has been observed by other scholars (Yang et al 2014;Liu et al 2015b). …”

Section: Facies Dsupporting

confidence: 80%

“…This is typical of sediments transported by plastic sandy debris flows (Zou et al 2012;Shanmugam 2013;Xian et al 2013). The planar fabric of the clasts further supports the hypothesis that the sediment was transported by plastic flows (Talling et al 2012a;Yang et al 2014). The presence of mudstone coats can be attributed to muddy slurry adhering to the clasts as they were rolled or spun by the shear stresses along their upper and lower surfaces (Li et al 2014(Li et al , 2016.…”

Section: Facies Bmentioning

confidence: 58%

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Origin and depositional model of deep-water lacustrine sandstone deposits in the 7th and 6th members of the Yanchang Formation (Late Triassic), Binchang area, Ordos Basin, China

et al. 2017

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Sandstones attributed to different lacustrine sediment gravity flows are present in the 7th and 6th members of the Yanchang Formation in the Ordos Basin, China. These differences in their origins led to different sandstone distributions which control the scale and connectivity of oil and gas reservoirs. Numerous cores and outcrops were analysed to understand the origins of these sandstones. The main origin of these sandstones was analysed by statistical methods, and well logging data were used to study their vertical and horizontal distributions. Results show that the sandstones in the study area accumulated via sandy debris flows, turbidity currents and slumping, and sandy debris flows predominate. The sandstone associated with a single event is characteristically small in scale and exhibits poor lateral continuity. However, as a result of multiple events that stacked gravity flow-related sandstones atop one another, sandstones are extensive overall, as illustrated in the cross section and isopach maps. Finally, a depositional model was developed in which sandy debris flows predominated and various other types of small-scale gravity flows occurred frequently, resulting in extensive deposition of sand bodies across a large area.

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Section: Facies Dsupporting

confidence: 80%

Section: Facies Bmentioning

confidence: 58%

Origin and depositional model of deep-water lacustrine sandstone deposits in the 7th and 6th members of the Yanchang Formation (Late Triassic), Binchang area, Ordos Basin, China

et al. 2017

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“…The depositional mechanisms of fine‐grained sediments include mass flow, bottom currents, and suspension deposition (Abouelresh & Slatt, ; Liang, Cao, Jiang, Wu, & Song, ; Liang et al, ; Loucks & Ruppel, ; Shanmugam, ; Yang, He, et al, ; Yang, Fan, Han, & Van Loon, ). A previous study showed that seven lithofacies were identified in the lower Silurian Longmaxi shale of Sichuan Basin (Liang et al, ): laminated calcareous mudstone, laminated carbonaceous mudstone, laminated silty mudstone, laminated claystone, laminated siliceous shale, siltstone, and massive mudstone.…”

Section: Discussionmentioning

confidence: 99%

Source analysis of quartz from the Upper Ordovician and Lower Silurian black shale and its effects on shale gas reservoir in the southern Sichuan Basin and its periphery, China

Han

Jiang

et al. 2018

Geological Journal

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A major breakthrough in shale gas exploration and development has been made concerning the black shale of the Upper Ordovician and Lower Silurian. In recent years, significant progresses have been made regarding the exploration and development of shale gas in the black shale of the Upper Ordovician and Lower Silurian. Accordingly, we investigated the petrological and geochemical characteristics of the black shale from WF2‐LM5 graptolite biozones and performed a source analysis of quartz as well as evaluated its effect on shale gas reservoirs. The black shale mainly contains clay, carbonate, and quartz with the average TOC of 2.21%. Three quartz types, Q1, Q2, and Q3, were identified via petrological and cathodoluminescence (CL) analysis. Q1 of detrital origin as suggested by its typical morphology with monocrystal structure, large grain‐size, subrounded to angular outlines, and clear edges. This is further supported by the occurrence of medium luminescence under cathodoluminescence and medium intensity of P1 and P2 and high intensity P3 according to CL images. Q2 accounts for more than 90% of quartz and exhibits cryptocrystalline texture, an irregular shape, blurring edges, and low luminescence, and its CL images show low intensity P1, low intensity P2, and high intensity P3. Q3 have the morphologies of siliceous organisms, for example, sponge spicules, radiolaria, and foraminifera. Q2 and Q3 belong to authigenic quartz derived from siliceous organisms. Th/U and V/Cr indicate black shale from LM1–3 mainly deposited in the dysoxic‐anoxic environment while black shale from LM4–5 deposited in the oxic environment. Authigenic quartz‐rich shales from LM1–3 were speculated to be the best shale gas reservoirs characterized by high TOC content, high gas content, and with negligible amount of detrital quartz. Compared with shale from LM1–3, black shale from LM4–5 usually have relatively high detrital quartz content and low TOC content and gas content. Considering the abundant interparticle pore space, the detrital quartz‐rich shale interbedded within the black shale from LM4–5, could also become good shale gas reservoirs if sufficient gas supply is guaranteed.

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“…Most C-P gases were generated during this period and migrated to nearby upper Paleozoic C-P reservoirs between source rocks. Driven by buoyancy and abnormal pressure, the gases also migrated directly upward or downward into the lower Paleozoic reservoirs over distances of <200 m [16,21,22]. From the end of the Early Cretaceous, thick strata were eroded and gas generation terminated, with the temperature reducing to the current 99.6-113.5°C [23].…”

Section: Thermal History and Gas Charge Model During The Latementioning

confidence: 99%

Carbon and Hydrogen Isotopic Reversals in Highly Mature Coal-Derived Gases: A Case Study of Paleozoic Gases in the Southern Ordos Basin, China

Liu

2019

Geofluids

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The compositional carbon isotopic seriesδ13C-CH4<δ13C-C2H6<δ13C-C3H8<δ13C-C4H10is common in thermogenic gases. With the exploration of deeper strata, however, isotopic reversals (δ13C-CH4>δ13C-C2H6>δ13C-C3H8) in overmature unconventional shale gases and conventional (coal-derived) gases have been identified. Paleozoic gases in the southern Ordos Basin, China, with partial or complete isotopic reversals, were studied as examples of isotopic fractionation in overmature coal-derived gases. Isotopic compositions of gases of different maturities from the Ordos Basin and shale gases from around the world were compared. Results indicate that carbon isotopic series are related to maturity. Complete isotopic reversal occurs mostly in regions with vitrinite reflectanceRo>2.4%. Where2.4%>Ro>2.0%, almost all gases display partial isotopic reversal, withδ13C-CH4>δ13C-C2H6orδ13C-C2H6>δ13C-C3H8. Carbon isotopic reversal in coal-derived gases is not caused by abiotic origin, the mixing of gases from different types of source rock, abiotic polymerization, wet gas cracking, and other mechanisms that contribute to reversal in shale gases. Based on the unique structure of coaly source rock and the geology of the Ordos Basin, closed-system aromatization-polycondensation reactions are considered the most likely cause of carbon isotopic reversal. During the reactions, isotopically light gases are generated by recombination of previously formed hydrocarbons and residual kerogen-coal. Hydrogen isotopic reversal in the southern Ordos Basin might also be caused by aromatization-polycondensation reactions.

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A Late Triassic gravity flow depositional system in the southern Ordos Basin

Cited by 74 publications

References 12 publications

Origin and depositional model of deep-water lacustrine sandstone deposits in the 7th and 6th members of the Yanchang Formation (Late Triassic), Binchang area, Ordos Basin, China

Origin and depositional model of deep-water lacustrine sandstone deposits in the 7th and 6th members of the Yanchang Formation (Late Triassic), Binchang area, Ordos Basin, China

Source analysis of quartz from the Upper Ordovician and Lower Silurian black shale and its effects on shale gas reservoir in the southern Sichuan Basin and its periphery, China

Carbon and Hydrogen Isotopic Reversals in Highly Mature Coal-Derived Gases: A Case Study of Paleozoic Gases in the Southern Ordos Basin, China

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