Geochemical characteristics and origins of natural gas in the Zhu III sub-basin, Pearl River Mouth Basin, China

Quan, Yongbin; Liu, Jianzhang; Hao, Fang; Bao, Xiaoyi; Xu, Shang; Teng, Changyu; Wang, Zhenfeng

doi:10.1016/j.marpetgeo.2018.12.007

Cited by 23 publications

(12 citation statements)

References 89 publications

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“…The factors of secondary microbial transformations, migration, thermal maturity, and genetic type also affect the drying coefficient from the perspective of natural gas accumulation (Quan et al, 2019). The methane-produced anaerobic organisms take priority to consume wet gas, resulting in an increase of the drying coefficient (Milkov, 2011;Milkov and Etiope, 2018).…”

Section: Chemical Composition Of Gas Hydrate and Free Gasmentioning

confidence: 99%

Origin of the Gas Hydrate and Free Gas in the Qilian Permafrost, Northwest China: Evidence from Molecular Composition and Carbon Isotopes

Tan

Yang

et al. 2021

Acta Geologica Sinica (Eng)

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The Qilian permafrost of the South Qilian Basin (SQB) has become a research focus since gas hydrates were discovered in 2009. Although many works from different perspectives have been conducted in this area, the origin of gas from gas hydrate is still controversial. Molecular composition and carbon isotope of 190 samples related to gas hydrates collected from 11 boreholes allowed exploration of genetic type, thermal maturity, biodegradation, as well as gas-source correlation of alkane gases from gas hydrates and free gases. Results indicate that alkane gases biodegraded after the formation of natural gas. According to differences in carbon isotopes of methane and their congeners (CH 4 , C 2 H 6 , C 3 H 8 ), the thermal maturity (vitrinite reflectance, VRo) of most alkane gases ranges from 0.6% to 1.5%, indicating a mature to high mature stage. The thermal maturity VRo of a small part of alkane gas (in boreholes DK5 and DK6) is higher than 1.3%, indicating a high mature stage. Alkane gases were mainly produced by secondary cracking, consisting of crude oilcracking gases and wet gases cracking to dry gases. Genetic types of alkane gases are primarily oil-type gases generated from shales and mudstones in the upper Yaojie Formation of Jurassic, with less coal-type gases originated from the mudstones in the Triassic Galedesi Formation and the lower Yaojie Formation of Jurassic. Carbon dioxides associated with alkanes from gas hydrates and free gases indicate the thermal decomposition and biodegradation of organic matter. The origins of natural gases from gas hydrates and free gases shed light on the evaluation of petroleum resource potential, deeply buried sediments, and petroleum resource exploration in the SQB.

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Section: Chemical Composition Of Gas Hydrate and Free Gasmentioning

confidence: 99%

Origin of the Gas Hydrate and Free Gas in the Qilian Permafrost, Northwest China: Evidence from Molecular Composition and Carbon Isotopes

Tan

Yang

et al. 2021

Acta Geologica Sinica (Eng)

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“…The PRMB is a typical passive margin Cenozoic rifted basin formed on pre-Tertiary basement (Quan et al, 2019). It is the largest depositional basin along the northern continental margin of the South China Sea Peng et al, 2018).…”

Section: Geological Backgroundmentioning

confidence: 99%

“…The basin can be divided into five tectonic zones from north to south: the northern uplift zone, northern sub-basin zone (made up of the Zhu I and Zhu III sub-basins), central uplift zone, southern subbasin zone (made up of the Zhu II and Chaoshan subbasins), and southern uplift zone (Fig. 1a) (Xie et al, 2014;He et al, 2017;Peng et al, 2017;Quan et al, 2019). The northern uplift zone, northern sub-basin zone, and central uplift zone are in the shallow-water area of PRMB and the other two tectonic zones are the deep-water area (Mi et al, 2018).…”

Section: Geological Backgroundmentioning

confidence: 99%

“…The Pearl River Mouth Basin (PRMB) is the largest depositional basin along the northern continental margin of the South China Sea and is one of the most petroliferous basins in China (Shi et al, 2014;Peng et al, 2017;Feng et al, 2017;Quan et al, 2019). A series of oil reservoirs has been discovered in the shallow-water area of PRMB and the oil is normal crude oil, with densities from 0.8 to 0.95 g/cm 3 (Hu et al, 2015;Peng et al, 2016b).…”

Section: Introductionmentioning

confidence: 99%

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Petroleum Migration Characteristics in the Northeastern Part of the Baiyun Depression, Pearl River Mouth Basin, South China Sea

Zeng

Wang

Guo³

et al. 2021

Acta Geologica Sinica (Eng)

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This paper investigates the origin and migration characteristics of petroleum in the northeastern part of the Baiyun Depression, Pearl River Mouth Basin (PRMB). The discovered petroleum in the study area is mainly located in the Lower Zhujiang Member (N 1 z 2) and mainly originated from the Enping Formation source rocks in the eastern sag. Active faults (vertical migration) and N 1 z 2 sandstones (lateral migration) acted as the petroleum migration systems. The fault activities in the Dongsha event controlled the episodic petroleum migration. Fractures in the fault zones provided effective conduits, and overpressure was the driving force. The vertical migration could not cross the fault zones laterally. The petroleum injection areas in the carrier beds were the contact zones of petroleum-migration faults and carrier beds. The lateral migration was steady-state migration, and buoyancy was the driving force. The migration pathways in the carrier beds were controlled by the structural morphology. Secondary petroleum migration in the study area could be divided into two parts: vertical migration along the fractures in the fault zones and lateral migration through preferential petroleum migration pathways (PPMPs) in the carrier beds. The petroleum migration behaviors, including migrating direction, driving force, and migration pattern, in the faults and sandstone carrier beds were quite different. This study provides a typical example for comprehending secondary migration processes and has great importance for determining future exploration targets in the deep-water area of the PRMB.

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“…Under the dual controls of crustal stretching and right-lateral strike-slip, the Zhu III Superdepression experienced three tectonic evolution stages: terrestrial fault lacustrine basin from Eocene to Early Oligocene (syn-rifting stage), fault depression basin from late Oligocene to Early Miocene (early postrifting stage), and depression basin since Middle Miocene (late postrifting stage) (Quan et al., 2019). As a result, the Zhu III Superdepression formed a typical double-layer structure similar to most Cenozoic fault basins in Eastern China.…”

Section: Geological Settingmentioning

confidence: 99%

Quality, hydrocarbon generation, and expulsion of the Eocene Enping Formation source rocks in the Wenchang Depression, western Pearl River Mouth Basin, South China Sea

Chen

Chang

et al. 2020

Energy Exploration & Exploitation

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Recently, increasing numbers of oil and gas reservoirs have been discovered in the Wenchang Depression, western Pearl River Mouth Basin, South China Sea, revealing prospects for hydrocarbon exploration. The Enping Formation (E3e) is a key target layer for the development of source rocks. However, previous work has only focused on lacustrine swamp source rocks of E3e in the Wenchang A Sag, without a systematic study of shallow lacustrine source rocks. In this study, the quality of E3e shallow lacustrine source rocks is reevaluated, and the hydrocarbon generation and expulsion characteristics are analyzed using relevant geological data and constructing a conceptual model. The results show that the E3e2 source rocks have greater thickness (50–600 m) and similar organic matter abundance (0.5–2.5%) compared with the E3e1 source rocks (50–500 m and 0.5–2.5%). On the whole, the E3e source rocks were deposited in the continental environment and are dominated by Type II and Type III kerogen. Meanwhile, the E3e source rocks of the Wenchang A Sag are in the stage of mature to over mature, while those of the Wenchang B Sag are in the stage of low mature. Vertically, the hydrocarbon generation potential of the E3e2 source rocks is greater than E3e1. Also, the cumulative hydrocarbon production of steep slope in the Wenchang A Sag is larger than that in the Wenchang B Sag. In addition, the corresponding vitrinite reflectances of hydrocarbon expulsion threshold and peak are 0.72 and 0.96%, respectively. Horizontally, four hydrocarbon generation and expulsion centers were mainly concentrated in different subsags of the Wenchang A and B Sags for E3e. The maximum values of hydrocarbon generation and expulsion intensity for E3e1 are 1500 × 104 t/km2 and 1000 × 104 t/km2, respectively, while those for E3e2 are 1800 × 104 t/km2 and 1200 × 104 t/km2, respectively, with the expulsion efficiency of 75%.

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Geochemical characteristics and origins of natural gas in the Zhu III sub-basin, Pearl River Mouth Basin, China

Cited by 23 publications

References 89 publications

Origin of the Gas Hydrate and Free Gas in the Qilian Permafrost, Northwest China: Evidence from Molecular Composition and Carbon Isotopes

Origin of the Gas Hydrate and Free Gas in the Qilian Permafrost, Northwest China: Evidence from Molecular Composition and Carbon Isotopes

Petroleum Migration Characteristics in the Northeastern Part of the Baiyun Depression, Pearl River Mouth Basin, South China Sea

Quality, hydrocarbon generation, and expulsion of the Eocene Enping Formation source rocks in the Wenchang Depression, western Pearl River Mouth Basin, South China Sea

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