scholarly journals Elemental Geochemical Characterization of Sedimentary Conditions and Organic Matter Enrichment for Lower Cambrian Shale Formations in Northern Guizhou, South China

Minerals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 793
Author(s):  
Shuangbiao Han ◽  
Yuanlong Zhang ◽  
Jie Huang ◽  
Yurun Rui ◽  
Zhiyuan Tang
Keyword(s):  
Organic Matter ◽  
Deposition Rate ◽  
Black Shale ◽  
South China ◽  
Shale Gas ◽  
Geochemical Data ◽  
Shale Formations ◽  
Average Value ◽  
Geochemical Elements ◽  
Niutitang Formation

The black shale deposited in the Niutitang Formation and its adjacent strata is considered to be a favorable source rock in northern Guizhou of south China and has become a target horizon for shale gas exploration in recent years. Based on SQ-1 and CY-1 core samples, the organic matter properties and geochemical elements were obtained through experimental analysis. Provenance, paleoredox, paleoclimate, paleoproductivity and deposition conditions were analyzed, and the sedimentary effects on organic matter enrichment were discussed. The results show that total organic carbon (TOC) is between 0.22–10.10 wt.% in SQ-1, with an average of 2.60 wt.%, and TOC is between 0.23–7.7 wt.% in CY-1, with an average of 1.45 wt.%. The geochemical data of the samples indicate that the black shale of the Niutitang Formation and adjacent strata are deposited in the tectonic background of the passive continental margin. The provenance shows moderate weathering, with hot and humid paleoenvironmental characteristics and fast deposition rate. Using multiple ancient redox indicators, it is concluded that the formation has undergone changes in the oxidizing environment and anaerobic environment during deposition. According to the (La/Yb)N value (the average value of SQ-1 is 1.23 and the average value of CY-1 is 1.26), it shows a faster deposition rate of the two wells and shortens the residence time of organic matter in the microbial degradation zone. The Babio indicates that the bottom has a high paleoproductivity when deposited. Considering the influencing factors, the paleoproductivity mainly controls the organic matter enrichment, followed by ancient redox conditions and the deposition rate. The research results provide a reference for deepening sedimentary understanding and shale gas exploration in the study area.

scholarly journals Geochemistry and Mineralogy of Lower Paleozoic Heituao Shale from Tadong Low Uplift of Tarim Basin, China: Implication for Shale Gas Development

Minerals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 635
Author(s):  
Shihu Zhao ◽  
Yanbin Wang ◽  
Yong Li ◽  
Honghui Li ◽  
Zhaohui Xu ◽  
...  
Keyword(s):  
Organic Matter ◽  
Tarim Basin ◽  
Shale Gas ◽  
Organic Matter Content ◽  
Matter Content ◽  
Mature Stage ◽  
Lower Paleozoic ◽  
Development Potential ◽  
Middle Ordovician ◽  
Average Value

Tarim Basin is the largest Petroliferous basin in China, while its shale gas development potential has not been fully revealed. The organic-rich black shale in middle Ordovician Heituao Formation from Tadong low uplift of Tarim Basin has been considered as an important source rock and has the characteristic of large thickness, high organic matter content and high thermal maturity degree. To obtain its development potential, geochemical, mineralogical and mechanics research is conducted based on Rock-Eval pyrolysis, total organic carbon (TOC), X-ray diffraction (XRD) and uniaxial compression experiments. The results show that: (1) the TOC content ranges between 0.63 and 2.51 wt% with an average value of 1.22 wt%, the Tmax values are 382–523 °C (average = 468.9 °C), and the S2 value is relatively low which ranges from 0.08 to 1.37 mg HC/g rock (averaging of 0.42 mg HC/g rock); (2) the organic matter of Heituao shale in Tadong low uplift show poor abundance as indicated by low S2 value, gas-prone property, and post mature stage (stage of dry gas). (3) Quartz is the main mineral component in Heituao shale samples, accounting for 26–94 wt% with an average of 72 wt%. Additionally, its Young’s modulus ranges from 20.0 to 23.1 GPa with an average of 21.2 GPa, Poisson’s ratio ranges between 0.11 and 0.21 (average = 0.15); (4) the fracability parameter of brittleness index (BI) ranges between 0.28 and 0.99 (averaging of 0.85), indicating good fracability potential of Heituao shale of Tadong low uplift and has the potential for shale gas development. This study reveals the shale gas accumulation potential in middle Ordovician of the Tarim Basin, and beneficial for future exploration and production practice.

scholarly journals Reservoir characteristics and controlling factor of shale gas in Lower Cambrian Niutitang Formation, South China

2018 ◽  
Vol 3 (3) ◽  
pp. 210-220 ◽  
Author(s):  
Pengfei Wang ◽  
Zhenxue Jiang ◽  
Bo Han ◽  
Peng Lv ◽  
Can Jin ◽  
...  
Keyword(s):  
South China ◽  
Shale Gas ◽  
Lower Cambrian ◽  
Controlling Factor ◽  
Reservoir Characteristics ◽  
Niutitang Formation

Shale gas potential of the major marine shale formations in the Upper Yangtze Platform, South China, Part II: Methane sorption capacity

Fuel ◽  
2014 ◽  
Vol 129 ◽  
pp. 204-218 ◽  
Author(s):  
Jingqiang Tan ◽  
Philipp Weniger ◽  
Bernhard Krooss ◽  
Alexej Merkel ◽  
Brian Horsfield ◽  
...  
Keyword(s):  
Sorption Capacity ◽  
South China ◽  
Shale Gas ◽  
Yangtze Platform ◽  
Shale Formations ◽  
Marine Shale ◽  
Methane Sorption ◽  
Gas Potential

Remagnetization of lower Silurian black shale and insights into shale gas in the Sichuan Basin, south China

2016 ◽  
Vol 121 (2) ◽  
pp. 491-505 ◽  
Author(s):  
Yong Zhang ◽  
Dong Jia ◽  
Hongwei Yin ◽  
Mancang Liu ◽  
Wuren Xie ◽  
...  
Keyword(s):  
Black Shale ◽  
South China ◽  
Shale Gas ◽  
Sichuan Basin ◽  
Lower Silurian ◽  
The Sichuan Basin

scholarly journals Constraints on the Organic Matter Accumulation of Lower Cambrian Niutitang Shales in the Middle Yangtze Region, South China

Lithosphere ◽  
2021 ◽  
Vol 2021 (Special 1) ◽  
Author(s):  
Xing Niu ◽  
Yini Liu ◽  
Detian Yan ◽  
Mingyi Hu ◽  
Zixuan Liu ◽  
...  
Keyword(s):  
Organic Matter ◽  
Sea Level ◽  
South China ◽  
Primary Productivity ◽  
Lower Cambrian ◽  
Hydrothermal Activity ◽  
Oxic Condition ◽  
Organic Matter Accumulation ◽  
Niutitang Formation ◽  
And Sea Level

Abstract The lower Cambrian Niutitang shales, as one of target intervals with the greatest potential for shale gas exploration and development, have attracted much attention. Nevertheless, the organic matter enrichment mechanisms of the lower Cambrian Niutitang shales need further study, especially in the hydrothermal active zone. In this study, samples from ND1 well in western Hubei Province, middle Yangtze region, South China, were investigated for the controlling factors of organic matter accumulation of Lower Cambrian Niutitang shales by detailed petrographic, mineralogic, and geochemical proxies. The results show that hydrothermal activity and sea level fluctuation controlled the redox conditions and paleoproductivity of seawater and ultimately controlled the organic matter accumulation of Niutitang formation. In the Niu-1 member, the intense hydrothermal events lead to a suboxic to anoxic environment, which is conducive to the organic matter preservation. However, low sea level strengthens the restriction of water mass and reduced nutrient upwelling into the shelf, leading to decreased marine primary productivity, which was ultimately responsible for depleted organic matter accumulation in the Niu-1 member. In the Niu-2 member, the anoxic-euxinic environment and high paleoproductivity, driven by continuous hydrothermal activity and rising sea level, were the main factors controlling the enrichment of organic matter. In the Niu-3 member, the dysoxic to oxic condition plus low primary productivity, caused by the disappearance of hydrothermal activities and sea-level fall, resulted in the unfavorable organic matter accumulation. The results of this paper enrich the model of organic matter enrichment in the lower Cambrian black shale in the middle Yangtze region.

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