Gas-bearing property of the Lower Cambrian Niutitang Formation shale and its influencing factors: A case study from the Cengong block, northern Guizhou Province, South China

Li, Zhen; Zhang, Jinchuan; Gong, Dajian; Tan, Jingqiang; Liu, Yang; Wang, Dongsheng; Li, Pei; Tong, Zhongzheng; Niu, Jialiang

doi:10.1016/j.marpetgeo.2020.104556

Cited by 32 publications

(16 citation statements)

References 65 publications

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“…In recent years, extensive geochemical studies have been carried out on the Lower Cambrian shales and some basic understandings are obtained [23,24,44,[51][52][53][54][55][56][57][58]. A brief overview of three aspects, including TOC, OM type, and maturity, can be concluded in the following.…”

Section: Geochemical and Gas-bearingmentioning

confidence: 99%

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Lower Cambrian Organic-Rich Shales in Southern China: A Review of Gas-Bearing Property, Pore Structure, and Their Controlling Factors

Gao

Xiao

et al. 2022

Geofluids

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The Lower Cambrian shales are widely developed in southern China, with greater thicknesses and higher TOC contents. Although the shale gas resource potential has been suggested to be huge, the shale gas exploration and development is not satisfactory. At present, the gas-bearing property evaluation of the Lower Cambrian shale is still a hot spot of concern. According to previous works, this paper systematically summarizes the gas-bearing characteristics and controlling factors of the Lower Cambrian shales in southern China. The buried depth of Lower Cambrian shales mainly ranges from 3000 m to 6000 m, and the thickness of organic-rich shale intervals ( TOC > 2 % ) varies from 20 m to 300 m. The TOC content and EqVRo value are generally up to 2%-10% and 2.5%-6.0%, respectively. The gas content of the Lower Cambrian shales in the Weiyuan-Qianwei block of the Sichuan Basin and the western Hubei area generally exceeds 2 m3/t, and gas composition is dominated by CH4. In southeastern Chongqing, northwestern Hunan, and northern Guizhou areas, the gas content of the Lower Cambrian shales is generally <2 m3/t, and the N2 content is generally >60%. In the Lower Yangtze region, the Lower Cambrian shale reservoirs basically contain no gas. Higher maturity, lower porosity, and less-no organic pores are suggested to be responsible for low gas contents and/or the predominate of N2 in shale gas reservoirs. Strong tectonic deformation is an important factor leading to the massive gas loss from shale reservoirs, thus resulting in no gas or only a small amount of N2 in the Lower Cambrian shales. In a word, the Lower Cambrian shale gas plays with low maturity and relatively stable tectonic condition, especially deep-ultradeep zones, may be the favorable targets for shale gas exploration.

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Section: Geochemical and Gas-bearingmentioning

confidence: 99%

“…In the whole Yangtze region, the Lower Cambrian shales have high maturity, with the EqVRo value ranging from 2.5% to 6.0% [30,33,56,[74][75][76][77][78]. The EqVRo value of the Lower Cambrian shales in the Upper-Middle Yangtze region mainly varies from 3.0% to 4.0%.…”

Section: Geochemical and Gas-bearingmentioning

confidence: 99%

Lower Cambrian Organic-Rich Shales in Southern China: A Review of Gas-Bearing Property, Pore Structure, and Their Controlling Factors

Gao

Xiao

et al. 2022

Geofluids

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“…10 f). There are primary intergranular pores, dissolved pores, and microcracks related to brittle minerals, which are conducive to the storage of shale gas, especially free gas 22 . In contrast, plastic clay minerals can be compressed and deformed under the action of stress and can increasingly fill pores, which is not conducive to pore preservation 57 .…”

Section: Resultsmentioning

confidence: 99%

“…Similarly, Chen et al 21 applied isotopic geochemical proxies in shale gas content prediction. In another work, Li et al 22 used the methane isothermal adsorption experiment and field gas desorption methods to obtain the adsorbed gas content and total gas content, respectively. Similarly, Xiao et al 23 calculated the adsorbed gas content and total gas content according to the Langmuir adsorption model and gas state equation and recovered the total gas content based on the AMOCO method, indicating that the calculated gas content suitably agreed with the recovered gas content.…”

Section: Introductionmentioning

confidence: 99%

Application of mathematical statistics to shale gas-bearing property evaluation and main controlling factor analysis

Pang

et al. 2022

Sci Rep

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Gas-bearing property evaluation and main controlling factor analysis have remained a concern in shale gas research. The application of principal component analysis, an important mathematical statistical method, in gas-bearing property evaluation and main controlling factor analysis of the Longmaxi shale in the Weirong area, Sichuan Basin, was examined. The Longmaxi shale exhibits high heterogeneity, manifested in the organic matter abundance, mineral composition, and pore structure. Seven geological factors, including the temperature, pressure, TOC content, clay content, brittle mineral content, pore volume, and specific surface area (SSA), were selected in principal component analysis. Four principal components with geological significance, such as mineral composition, formation condition, pore structure, and organic matter abundance, were extracted through principal component analysis, and further constituted a comprehensive factor. Shale gas-bearing properties were evaluated according to the score of the comprehensive factor. The Longmaxi shale could be identified as exhibiting good, medium, and poor gas-bearing properties based on the comprehensive factor scores of these samples. According to each geological factor’s contribution to the comprehensive factor, combined with geological analysis, it could be considered that gas-bearing properties are primarily controlled by pore volume, SSA, and clay content, followed by TOC content, brittle mineral content, temperature and pressure.

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“…TOC content of the Niutitang shale in Southern Guizhou mainly ranges between 2.7% and 4.0%, with an average value of 3.41% [45]. The Eq-R o of the Niutitang shale in Southern Guizhou is generally below 3.0%, with an average value of 2.4% [46,47]. Minerals of the Niutitang shale in Southern Guizhou are also dominated by quartz, clay, and carbonate [10,11].…”

Section: Geofluidsmentioning

confidence: 99%

Slope Belts of Paleouplifts Control the Pore Structure of Organic Matter of Marine Shale: A Comparative Study of Lower Cambrian Rocks in the Sichuan Basin

et al. 2021

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Extensive exploration of the marine shale of the Niutitang Formation in south China has been conducted. However, exploration and development results have varied considerably in different areas. For example, the Niutitang shale in Jingyan City (Southwestern Sichuan Basin) produces a large amount of gas with a long period of stable production. In contrast, most development wells in the Niutitang shale in Chongqing City do not produce gas. Scanning electron microscopy images showed that the organic matter (OM) pore development in the Niutitang shale in Jingyan is abundant, large in size, and are well connected. In contrast, OM pores in the Niutitang shale in Chongqing are rarely observed. OM pore development of the Jingyan and Chongqing shales is mainly controlled by thermal maturity as shown by equivalent vitrine reflectance determinations. The moderate thermal maturity has resulted in the development of a large number of OM pores in the Niutitang shale in Jingyan, whereas the high thermal maturity of the Niutitang shale in Chongqing has led to the destruction of most of the OM pores. Due to the existence of ancient uplift, the shale was buried shallowly in the process of hydrocarbon generation evolution, and the shale avoided excessive thermal evolution and retained appropriate thermal maturity. In the Jingyan area, due to its location near the central uplift in the Sichuan Basin, the Niutitang shale deposited nearby avoided excessive evolution, and a large number of OM pores were retained in the reservoir.

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Gas-bearing property of the Lower Cambrian Niutitang Formation shale and its influencing factors: A case study from the Cengong block, northern Guizhou Province, South China

Cited by 32 publications

References 65 publications

Lower Cambrian Organic-Rich Shales in Southern China: A Review of Gas-Bearing Property, Pore Structure, and Their Controlling Factors

Lower Cambrian Organic-Rich Shales in Southern China: A Review of Gas-Bearing Property, Pore Structure, and Their Controlling Factors

Application of mathematical statistics to shale gas-bearing property evaluation and main controlling factor analysis

Slope Belts of Paleouplifts Control the Pore Structure of Organic Matter of Marine Shale: A Comparative Study of Lower Cambrian Rocks in the Sichuan Basin

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