Source rock characteristics and hydrocarbon expulsion potential of the Middle Eocene Wenchang formation in the Huizhou depression, Pearl River Mouth basin, south China sea

Jiang, Hang; Pang, Xiongqi; Hu, Shi; Qiu-hua, YU; Cao, Zhe; Yu, Rui; Chen, Di; Long, Zhilin; Jiang, Fujie

doi:10.1016/j.marpetgeo.2015.06.010

Cited by 46 publications

(22 citation statements)

References 30 publications

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“…Tectonic units of the Pearl River Mouth Basin, showing location of the studied wells (Panel (a)‐modified after Jiang et al, ; Panel (b) modified from Zhu & Mi, ) [Colour figure can be viewed at wileyonlinelibrary.com]…”

Section: Geological Settingmentioning

confidence: 99%

“…The elemental geochemistry of sediments has been widely used to investigate sediment provenance and weathering intensity and to understand tectonic settings (Bakkiaraj, Nagendra, Nagarajan, & Armstrong‐Altrin, ; Boynton, ; Condie, ; Dickinson et al, ; Floyd & Leveridge, ; Fedo, Nesbitt, & Young, ; Madhavaraju, ; McLennan, Hemming, McDaniel, & Hanson, ; Nesbitt & Markovics, ; Paikaray, Banerjee, & Mukherji, ; Roser & Korsch, ; Schieber, ; Sun, Zhou, Yan, Li, & Ma, ; Wang & Zhou, ). Heavy minerals can also be used to identify provenance, and detrital zircon U–Pb geochronological analyses provide age constraints on the maximum depositional ages of sediments (Cao, Jiang, Wang, Zhang, & Sun, ; Jiang et al, ; Liu et al, ; Li, Zhang, Li, & Fu, ; Shao et al, ; Xiang et al, ; Zhao et al, ), making them powerful tools for basin provenance analysis that has been widely used throughout the world during the last decade.…”

Section: Introductionmentioning

confidence: 99%

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Petrography and geochemistry of Oligocene to Lower Miocene sandstones in the Baiyun Sag, Pearl River Mouth Basin, South China Sea: Provenance, source area weathering, and tectonic setting

Chen

et al. 2018

Geological Journal

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There is a controversy regarding the source area and weathering intensity of Oligocene to Lower Miocene sediments in the Baiyun Sag of the Pearl River Mouth Basin.Detrital modes, geochemistry, heavy mineral data, and detrital zircon U-Pb ages were analysed to understand the provenance, source area weathering, and tectonic setting of Oligocene to Lower Miocene sandstones in the Baiyun Sag. Petrographic data reveal that the sandstones were derived from a recycled orogen. With increasing transport distance, sediment maturity increased correspondingly. The Oligocene to Lower Miocene sandstones in the Baiyun Sag have low compositional maturity and have experienced low to moderate weathering. The sediments of the Zhuhai Formation have experienced relatively strong weathering intensity compared with those of the Enping and lower Zhujiang formations. Due to low degree of illitization and differences in the geochemical compositions of the sediments, the continental island arc data from different boreholes in the Baiyun Sag are more irregularly distributed in the A-CN-K plot. The modal composition (e.g., quartz, feldspar, and lithic fragments) and geochemical indices (Al 2 O 3 /TiO 2 ratio; Al 2 O 3 -TiO 2 diagram; discriminant F1-F2 diagram; Eu/Eu*, La/Sc, La/Co, Th/Sc, and Th/Co ratios; Hf-La/Th and La/Sc-Co/Th diagrams; and rare earth element patterns) indicate that the sediments in the Baiyun Sag are mainly derived from felsic source rocks. Although the uplift around the Baiyun Sag includes multistage magmatism and basic rocks, it has little influence on the sediment in the depression, and no sediments were transported by the Han River to the Baiyun Sag. Geochemical data and detrital zircon U-Pb ages suggest that the Pearl River was formed in the Early Oligocene and became the main source for the sediments in this area. The river carried felsic material from the South China Coast forming a large delta on the northern slope of the Baiyun Sag. The ratios of Eu/Eu*, La/Sc, La/ Co, Th/Sc and Th/Co, and heavy mineral data indicate that the sediments transported by the Pearl River to the Baiyun Sag were changed from the arc-dominated coastal zone to the interior of the South China Block during the Late Oligocene to Early Miocene and even reached the south-eastern margin of the Tibetan Plateau (West Yunnan Plateau). The La-Th-Sc and Th-Sc-Zr/10 diagrams suggest that the provenance of these sandstones is evolved continental island arc or an active continental margin setting.

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Section: Geological Settingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Petrography and geochemistry of Oligocene to Lower Miocene sandstones in the Baiyun Sag, Pearl River Mouth Basin, South China Sea: Provenance, source area weathering, and tectonic setting

Chen

et al. 2018

Geological Journal

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“…In Wenchang Field, the middle-deep lacustrine source rocks consist of taupe mud and shale, which contain abundant C30 4-methyl steranes (Chen and Cunmin, 1993). ese types of source rocks are of high quality, as they were deposited in a lacustrine-weak oxidation-weak reduction sedimentary environment (Jiang et al, 2015). ese source rocks bearing oil-generating potential are characterized by abnormally high amplitudes and dominant low frequency on the seismic image, and they have been validated by recent drilling in the Wenchang 19 Depression.…”

Section: Introductionmentioning

confidence: 99%

Revealing new hydrocarbon potential through Q-compensated prestack depth imaging at Wenchang Field, South China Sea

Li¹,

Li²,

Xu³

et al. 2019

The Leading Edge

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Wenchang Field in the South China Sea contains a well-developed fault system, resulting in complex subsurface geology. Imaging the complex fault system plays an important role in hydrocarbon exploration in this area since the fault system forms a link between the source rocks and reservoirs. However, it is difficult to obtain a high-quality depth image of the fault system due to the effects of complex velocity and seismic absorption. Inaccurate depth velocities lead to fault shadows and structure distortions at the target zone. Absorption effects further deteriorate seismic imaging as they cause amplitude attenuation, phase distortion, and resolution reduction. We demonstrate how a combination of high-resolution depth velocity modeling and Q imaging work together to resolve these challenges. This workflow provides a step change in image quality of the complex fault system and targeted source rocks at Wenchang Field, significantly enhancing structure interpretation and reservoir delineation. A couple of commercial discoveries have been made, and several other potential hydrocarbon reservoirs have been identified based on the reprocessed data, which reveal new hydrocarbon potential in this region.

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“…Consequently, the limited drilled cores and rock cuttings available are valuable materials for generating information on hydrocarbon exploration. In addition, detailed investigations of drill core and cutting samples are required to make proper assessment of geological and geochemical characteristics (e.g., source rock quality and maturity) to fully evaluate oil and gas resource potential (Jiang et al 2015;Ratnayake et al 2018).…”

Section: Introductionmentioning

confidence: 99%

“…Molecular-level studies have been widely used to determine the degree of contamination, even in trace-contaminated rock-cutting samples. Gas chromatography combined with mass spectrometry (GC-MS) is one of the most powerful analytical techniques available for characterizing individual molecular compositions of different hydrocarbon fractions (e.g., Moldowan et al 1985;Brassell et al 1986;Budzinski et al 1995;Vékey 2001;Ratnayake et al 2005;Cortes et al 2010;Zhang et al 2012;Jiang et al 2015). This analytical technique can be successfully applied to distinguish indigenous and contaminant hydrocarbons in the sedimentary organic matter.…”

Section: Introductionmentioning

confidence: 99%

Organic geochemical evaluation of contamination tracers in deepwater well rock cuttings from the Mannar Basin, Sri Lanka

Ratnayake

Sampei

2018

J Petrol Explor Prod Technol

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Geochemical data from rock-cutting samples can give rise to faulty interpretations due to contamination from drilling fluids used in modern deepwater petroleum exploration. In this study, oil-based drilling contaminants were removed by solvent extraction with dichloromethane and methanol (9:1) solution. Bulk and molecular organic geochemical characteristics were examined for both oil-based drilling mud and cleaned rock-cutting samples. Total organic carbon (TOC) values are notably high in heavy liquid oil-based drilling mud mixtures (TOC = 21.4-63.3%, average = 34.6% ± 8.6) compared to cleaned rock cuttings (TOC = 0.4-1.5%, average = 0.8% ± 0.3). In addition, drilling mud mixtures contain higher concentrations of unresolved complex mixtures (UCM) in the n-alkanes fraction. Therefore, it is difficult to distinguish individual homologues in the n-alkanes fraction. The triterpanes also have relatively high UCM contents compared to steranes fractions. However, hydrocarbon homologues can be identified in both the triterpanes and steranes fractions of oil-based drilling mud mixtures. Gas chromatograms indicate that the n-alkanes fractions of rock cuttings initially cleaned with solvent still show considerable contamination from drilling fluids. This remaining contamination was removed by an additional cleaning step using the soxhlet extraction technique. The triterpanes fraction in solvent-cleaned rock cuttings does not contain an overprint of heavy liquid oil-based drilling mud contamination. However, solvent-cleaned rock cuttings may still retain contamination signatures at the sterane C 28 -20R homologue due to coelution. The geochemical overprint of contaminants in the cleaned rock cuttings can be interpreted as infiltration of lower molecular weight compounds into micro-cracks of the cuttings. The distribution of these molecules varies in each hydrocarbon fraction. Therefore, close inspection of contamination effects is required before interpretation of traditional organic geochemical proxies such as source rock characteristics and maturity.

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Source rock characteristics and hydrocarbon expulsion potential of the Middle Eocene Wenchang formation in the Huizhou depression, Pearl River Mouth basin, south China sea

Cited by 46 publications

References 30 publications

Petrography and geochemistry of Oligocene to Lower Miocene sandstones in the Baiyun Sag, Pearl River Mouth Basin, South China Sea: Provenance, source area weathering, and tectonic setting

Petrography and geochemistry of Oligocene to Lower Miocene sandstones in the Baiyun Sag, Pearl River Mouth Basin, South China Sea: Provenance, source area weathering, and tectonic setting

Revealing new hydrocarbon potential through Q-compensated prestack depth imaging at Wenchang Field, South China Sea

Organic geochemical evaluation of contamination tracers in deepwater well rock cuttings from the Mannar Basin, Sri Lanka

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