scholarly journals H 2 S formation and enrichment mechanisms in medium to large scale natural gas fields (reservoirs) in the Sichuan Basin

2010 ◽  
Vol 37 (5) ◽  
pp. 513-522 ◽  
Author(s):  
Liu Wenhui ◽  
Tenger ◽  
Gao Bo ◽  
Zhang Zhongning ◽  
Zhang Jianyong ◽  
...  
Keyword(s):  
Natural Gas ◽  
Sichuan Basin ◽  
Large Scale ◽  
The Sichuan Basin ◽  
Gas Fields

scholarly journals Factors Affecting Shale Gas Chemistry and Stable Isotope and Noble Gas Isotope Composition and Distribution: A Case Study of Lower Silurian Longmaxi Shale Gas, Sichuan Basin

Energies ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5981
Author(s):  
Chunhui Cao ◽  
Liwu Li ◽  
Yuhu Liu ◽  
Li Du ◽  
Zhongping Li ◽  
...  
Keyword(s):  
Natural Gas ◽  
Isotopic Composition ◽  
Shale Gas ◽  
Sichuan Basin ◽  
Noble Gas ◽  
Longmaxi Formation ◽  
Lower Silurian ◽  
The Sichuan Basin ◽  
Gas Fields ◽  
Cracking Gas

The Weiyuan (WY) and Changning (CN) fields are the largest shale gas fields in the Sichuan Basin. Though the shale gases in both fields are sourced from the Longmaxi Formation, this study found notable differences between them in molecular composition, carbon isotopic composition, and noble gas abundance and isotopic composition. CO2 (av. 0.52%) and N2 (av. 0.94%) were higher in Weiyuan than in Changning by an average of 0.45% and 0.70%, respectively. The δ13C1 (−26.9% to −29.7%) and δ13C2 (−32.0% to −34.9%) ratios in the Changning shale gases were about 8% and 6% heavier than those in Weiyuan, respectively. Both shale gases had similar 3He/4He ratios but different 40Ar/36Ar ratios. These geochemical differences indicated complex geological conditions and shed light on the evolution of the Lonmaxi shale gas in the Sichuan Basin. In this study, we highlight the possible impacts on the geochemical characteristics of gas due to tectonic activity, thermal evolution, and migration. By combining previous gas geochemical data and the geological background of these natural gas fields, we concluded that four factors account for the differences in the Longmaxi Formation shale gas in the Sichuan Basin: a) A different ratio of oil cracking gas and kerogen cracking gas mixed in the closed system at the high over-mature stage. b) The Longmaxi shales in WY and CN have had differential geothermal histories, especially in terms of the effects from the Emeishan Large Igneous Province (LIP), which have led to the discrepancy in evolution of the shales in the two areas. c) The heterogeneity of the Lower Silurian Longmaxi shales is another important factor, according to the noble gas data. d) Although shale gas is generated in closed systems, natural gas loss throughout geological history cannot be avoided, which also accounts for gas geochemical differences. This research offers some useful information regarding the theory of shale gas generation and evolution.

Molecular and petrographical evidence for lacustrine environmental and biotic change in the palaeo-Sichuan mega-lake (China) during the Toarcian Oceanic Anoxic Event

2021 ◽  
pp. SP514-2021-2
Author(s):  
Weimu Xu ◽  
Johan W. H. Weijers ◽  
Micha Ruhl ◽  
Erdem F. Idiz ◽  
Hugh C. Jenkyns ◽  
...  
Keyword(s):  
Organic Matter ◽  
Sichuan Basin ◽  
Large Scale ◽  
Algal Growth ◽  
Black Shales ◽  
Content Type ◽  
Oceanic Anoxic Event ◽  
Anoxic Event ◽  
Supplementary Material ◽  
The Sichuan Basin

AbstractThe organic-rich upper Lower Jurassic Da'anzhai Member (Ziliujing Formation) of the Sichuan Basin, China is the first stratigraphically well-constrained lacustrine succession associated with the Toarcian Oceanic Anoxic Event (T-OAE; ∼183 Ma). The formation and/or expansion of the Sichuan mega-lake, likely one of the most extensive fresh-water systems to have existed on the planet, is marked by large-scale lacustrine organic productivity and carbon burial during the T-OAE, possibly due to intensified hydrological cycling and nutrient supply. New molecular biomarker and organic petrographical analyses, combined with bulk organic and inorganic geochemical and palynological data, are presented here, providing insight into aquatic productivity, land-plant biodiversity, and terrestrial ecosystem evolution in continental interiors during the T-OAE. We show that lacustrine algal growth during the T-OAE accounted for a significant organic-matter flux to the lakebed in the palaeo-Sichuan mega-lake. Lacustrine water-column stratification during the T-OAE facilitated the formation of dysoxic-anoxic conditions at the lake bottom, favouring organic-matter preservation and carbon sequestration into organic-rich black shales in the Sichuan Basin. We attribute the palaeo-Sichuan mega-lake expansion to enhanced hydrological cycling in a more vigorous monsoonal climate in the hinterland during the T-OAE greenhouse.Supplementary material at https://doi.org/10.6084/m9.figshare.c.5433544

scholarly journals Geochemical characteristics of ultra-deep natural gas in the Sichuan Basin, SW China

2018 ◽  
Vol 45 (4) ◽  
pp. 619-628 ◽  
Author(s):  
Jinxing DAI ◽  
Yunyan NI ◽  
Shengfei QIN ◽  
Shipeng HUANG ◽  
Weilong PENG ◽  
...  
Keyword(s):  
Natural Gas ◽  
Sichuan Basin ◽  
Geochemical Characteristics ◽  
Sw China ◽  
The Sichuan Basin

Carbon isotopic composition and genetic types of natural gas in the Sichuan Basin, China

2016 ◽  
Vol 36 (1) ◽  
pp. 102-111
Author(s):  
Jin-ning Peng ◽  
Dong-yan Wang ◽  
Guang-xiang Liu ◽  
Min Zhang ◽  
Feng-li Li
Keyword(s):  
Natural Gas ◽  
Isotopic Composition ◽  
Sichuan Basin ◽  
Carbon Isotopic Composition ◽  
Carbon Isotopic ◽  
Genetic Types ◽  
The Sichuan Basin

Origin of methane-rich natural gas in Japan: formation of gas fields due to large-scale submarine volcanism

1990 ◽  
Vol 5 (3) ◽  
pp. 263-278 ◽  
Author(s):  
H. Wakita ◽  
Y. Sano ◽  
A. Urabe ◽  
Y. Nakamura
Keyword(s):  
Natural Gas ◽  
Large Scale ◽  
Submarine Volcanism ◽  
Gas Fields

scholarly journals Exploration status of the deep Sinian strata in the Sichuan Basin: Formation conditions of old giant carbonate oil/gas fields

2020 ◽  
Vol 7 (5) ◽  
pp. 462-472
Author(s):  
Wenzhi Zhao ◽  
Zecheng Wang ◽  
Hua Jiang ◽  
Xiaodong Fu ◽  
Wuren Xie ◽  
...  
Keyword(s):  
Sichuan Basin ◽  
Basin Formation ◽  
Formation Conditions ◽  
The Sichuan Basin ◽  
Gas Fields ◽  
Oil Gas

scholarly journals Formation conditions, accumulation models and exploration direction of large-scale gas fields in Sinian-Cambrian, Sichuan Basin, China

2016 ◽  
Vol 1 (1) ◽  
pp. 9-19 ◽  
Author(s):  
Guoqi Wei ◽  
Wei Yang ◽  
Wuren Xie ◽  
Zengye Xie ◽  
Fuying Zeng ◽  
...  
Keyword(s):  
Sichuan Basin ◽  
Large Scale ◽  
Formation Conditions ◽  
Gas Fields

scholarly journals Basic characteristics and accumulation mechanism of Sinian−Cambrian giant highly mature and oil-cracking gas reservoirs in the Sichuan Basin, SW China

2017 ◽  
Vol 36 (4) ◽  
pp. 568-590 ◽  
Author(s):  
Bing Luo ◽  
Yu Yang ◽  
Gang Zhou ◽  
Wenjun Luo ◽  
Shujiao Shan ◽  
...  
Keyword(s):  
Natural Gas ◽  
Lower Cambrian ◽  
Sichuan Basin ◽  
Large Scale ◽  
Oil And Gas ◽  
Source Rocks ◽  
Burial Depth ◽  
Sw China ◽  
Accumulation Mechanism ◽  
Oil Cracking

Old Mesoproterozoic−Cambrian successions have been regarded as an important frontier field for global oil and gas exploration in the 21st century. This has been confirmed by a recent natural gas exploration breakthrough in the Sinian and Cambrian strata, central Sichuan Uplift, Sichuan Basin of SW China. However, the accumulation mechanism and enrichment rule of these gases have not been well characterized. This was addressed in this work, with aims to provide important guidance for the further exploration while enriching the general studies of the oil and gas geology in the old Mesoproterozoic–Cambrian strata. Results show that the gas field in the study area is featured by old target layers (Sinian–Lower Cambrian), large burial depth (>4500 m), multiple gas-bearing intervals (the second and fourth members of the Sinian Dengying Formation and the Lower Cambrian Longwangmiao Formation), various gas reservoir types (structural type and structural–lithologic type), large scale (giant), and superimposing and ubiquitous distribution. The giant reserves could be attributed to the extensive intercalation of pervasive high quality source rocks and large-scale karst reservoirs, which enables a three-dimensional hydrocarbon migration and accumulation pattern. The origin of natural gas is oil cracking, and the three critical stages of accumulation include the formation of oil reservoirs in Triassic, the cracking of oil in Cretaceous, and the adjustment and reaccumulations in the Paleogene. The main controlling factor of oil and gas enrichment is the inherited development of large-scale stable paleo-uplift, and the high points in the eastern paleo-uplift are the favorable area for ​natural gas exploration.

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