Paleoenvironment and Controlling Factors of Oligocene Source Rock in the Eastern Deep-Water Area of the Qiongdongnan Basin: Evidences from Organic Geochemistry and Palynology

Wu, Piao; Hou, Dujie; Gan, Jun; Li, Xing; Ding, Wenjing; Li, Gang; Wu, Bing-Fei

doi:10.1021/acs.energyfuels.8b01190

Cited by 18 publications

(13 citation statements)

References 26 publications

(33 reference statements)

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“…Organic geochemistry analysis is an important approach to evaluate the petroliferous basin. − The C 27 , C 28 , and C 29 RS contents of rock extracts can be used to analyze the depositional environment of OM. − C 27 RS originates from plankton, whereas C 29 RS typically originates from higher terrestrial plants. , The ternary plot in this study shows that all of the samples are characterized by planktonic and/or bacterial sources (Figure ).…”

Section: Resultsmentioning

confidence: 77%

Hydrocarbon Generation Evaluation, Burial History, and Thermal Maturity of the Lower Triassic–Silurian Organic-Rich Sedimentary Rocks in the Central Uplift of the South Yellow Sea Basin, East Asia

et al. 2020

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This study focuses on the organic-rich rocks in the Central Uplift of the South Yellow Sea Basin (SYSB) using the CSDP-2 borehole, which was drilled through the integrated Lower Triassic–Silurian sediments and yielded approximately 2736 m of cores. Geochemical analyses of core samples, including Rock-Eval pyrolysis, elemental analysis, maceral analysis, and gas chromatography–mass spectrometry, revealed multiple sets of effective source rocks developed from the Lower Triassic Qinglong Formation to the Lower Silurian Gaojiabian Formation. The organic matter is dominated by types II1–2–III kerogen, most of which are mature to post-mature. Comprehensive geochemical analysis shows that Permian and Lower Carboniferous mudstones are the most important source rocks and have strong hydrocarbon generation capacity. Most of the source rocks are dominated by planktonic/bacterial sources, deposited mainly in a low-salinity marine environment, and influenced by the input of terrigenous detrital materials. Basin modeling results show that most of the Paleozoic–Mesozoic source rocks in the Central Uplift generally entered the oil-generation window during the Triassic to Late Jurassic. The timing of hydrocarbon generation and expulsion was simultaneous or earlier than the collisional orogenic movement between the Sino–Korean Platform and the Lower Yangtze Craton, which may have some destructive impact on the oil and gas preservation. Therefore, it is preservation condition rather than source rocks that may be one of the most important elements for hydrocarbon accumulation in the Central Uplift of the SYSB.

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Section: Resultsmentioning

confidence: 77%

Hydrocarbon Generation Evaluation, Burial History, and Thermal Maturity of the Lower Triassic–Silurian Organic-Rich Sedimentary Rocks in the Central Uplift of the South Yellow Sea Basin, East Asia

et al. 2020

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“…Considering the results of rock pyrolysis from the sidecores (Figure c), the kerogen maceral compositions (Figure ), and previous studies, , the organic matter type in the Qiongdongnan Basin are dominated by type III−II 2 . As shown in Figures and , and the well profile of B21-1, shale cutting samples from wells using HEM drilling fluid appear to be significantly contaminated by organic drilling additives, while sidecore samples are minimally affected.…”

Section: Discussionmentioning

confidence: 89%

“…The effectiveness of our correction results can be evaluated by comparing them with the sidecore samples. According to Figure , based on the measured pyrolysis data, the organic matter type of most cuttings from well B21-1S is classified as type II 1 to I, which obviously does not match the geological background of type III to II 2 in the Qiongdongnan Basin. , After our correction, the sample points of the contaminated cuttings regress to type III to II 2 , which parallels with the associated sidecores, indicating the reliability of our correction method.…”

Section: Discussionmentioning

confidence: 91%

Influence of HEM Drilling Fluid on Organic Geochemical Characteristics of Deep-Water Source Rocks in the Qiongdongnan Basin

Zhang,

Hou,

Cheng

et al. 2024

ACS Omega

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The influence of oil-based drilling fluid on the geochemical characteristics of source rocks has been widely reported in the northern South China Sea. However, contamination from water-based HEM drilling fluid has long been neglected in previous deep-water petroleum exploration. To further understand the impacts of HEM drilling fluid on deep-water source rocks, the organic matter abundance and type, kerogen maceral composition, and saturated biomarkers of the deep-water source rocks in the Qiongdongnan Basin were investigated. The influence of HEM drilling fluid on the organic geochemistry data of cuttings is significant but minor for sidecores. It is evident that the organic drilling additives in HEM drilling fluid can increase the organic matter abundance and optimize the organic matter types of shale cuttings. Specifically, the total organic carbon, S 1 , S 2 , and hydrogen index are increased by 28.5 ± 6.1, 90.8 ± 2.0, 34.2 ± 2.0, and 51.9 ± 4.0%, respectively. Furthermore, the organic drilling additives will greatly enhance the levels of C 29 regular steranes, especially for C 29 -ααα-20R sterane, with the influence still persisting even when conducting GC-MS-MS analysis. The highly abundant 17α (H) -22, 29, 30-trisnorhopane, 17β (H)-22, 29, 30-trisnorhopane, C 29−31 17α (H), 21β (H) hopanes, and C 29−31 17β (H), 21α (H) hopanes may directly originate from the organic drilling additives. It is dangerous to directly use organic geochemical data from deep-water source rock cuttings contaminated by HEM drilling fluid as it may lead to conclusions that are entirely inconsistent with the basin's geological background.

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“…The delta plays an important role in Source-to-Sink in the Qiongdongnan Basin, as the intensive interactions between marine and terrestrial geological agents in delta-marginal sea systems result in a mixed geochemical characteristic of marine and terrestrial organic matter in marine source rocks. − Terrigenous organic matter preserved in marine sediment acts as a valuable recorder of paleovegetation and paleoclimatic variations in the source areas . Tracing their fates in delta-marginal sea systems can help understanding the enrichment mechanisms of organic matter in marine source rocks. , The occurrence of high contents of oleanane-type terpanes and bicadinanes in the Qiongdongnan Basin confirmed the angiosperm sources .…”

Section: Introductionmentioning

confidence: 99%

Accumulation and Quantitative Assessment of Terrigenous Organic Matter in Upper Oligocene to Lower Miocene Marine Source Rocks of the Qiongdongnan Basin

Zhang,

Hou,

et al. 2024

ACS Omega

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The intense collision between marine and terrestrial agents results in the dual-source (marine and terrigenous) characteristics of marine source rocks. Our research quantitatively assessed terrestrial organic matter and revealed the crucial role of terrestrial organic materials in the organic matter enrichment of lower Miocene to upper Oligocene marine source rocks in the Qiongdognnan Basin. The quantitative assessment was achieved using partial least-squares analysis with eight biomarker parameters associated with n-alkanes, isoprenoids, bicadinanes, taraxerane, tricyclic terpanes, and gammacerane. Differential unloading of terrestrial organic materials based on sedimentary facies of the delta-marginal sea system were observed through oleanane and bicadinane contents. It should be noted that the diagnostic ratio of oleanane was excluded from the quantitative analysis due to the dual influence from differential unloading and contact with seawater of the terrestrial organic materials. Calculation results show that the terrestrial organic matter was highest in the delta front at 70%, followed by prodelta at 59% and inner shallow marine at 57%. From the late Oligocene to the early Miocene, the proportion of terrestrial organic matter in marine source rocks continuously increased, with the highest average value observed in the second member of the Sanya Formation at 69% and the lowest occurring in the third member of the Lingshui Formation at 46%. Increasing terrestrial organic material inputs and preservation driven by the East Asian summer monsoon provided first-order control of the accumulation of organic carbon in the Qiongdongnan Basin during late Oligocene to early Miocene, rather than the bioproductivity of marine algae. The redox conditions of the water column determine the enrichment extent of organic matter.

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Paleoenvironment and Controlling Factors of Oligocene Source Rock in the Eastern Deep-Water Area of the Qiongdongnan Basin: Evidences from Organic Geochemistry and Palynology

Cited by 18 publications

References 26 publications

Hydrocarbon Generation Evaluation, Burial History, and Thermal Maturity of the Lower Triassic–Silurian Organic-Rich Sedimentary Rocks in the Central Uplift of the South Yellow Sea Basin, East Asia

Hydrocarbon Generation Evaluation, Burial History, and Thermal Maturity of the Lower Triassic–Silurian Organic-Rich Sedimentary Rocks in the Central Uplift of the South Yellow Sea Basin, East Asia

Influence of HEM Drilling Fluid on Organic Geochemical Characteristics of Deep-Water Source Rocks in the Qiongdongnan Basin

Accumulation and Quantitative Assessment of Terrigenous Organic Matter in Upper Oligocene to Lower Miocene Marine Source Rocks of the Qiongdongnan Basin

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