Controls of organic and inorganic compositions on pore structure of lacustrine shales of Chang 7 member from Triassic Yanchang Formation in the Ordos Basin, China

Han, Hwataik; Pang, Peng; Li, Zhao-liang; Pi-tong, Shi; Guo, Chen; Liu, Yan; Chen, Shi-jia; Lu, Jungang; Gao, Yuan

doi:10.1016/j.marpetgeo.2018.10.038

Cited by 59 publications

(36 citation statements)

References 44 publications

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“…The intense heterogeneity of shale pore structure results in distinct shale gas storage mechanisms and distribution characteristics [5][6][7], while pore structure is influenced by rock type, mineral composition (mineral types, sizes, and percentage), organic maturity and total organic carbon content [5,8,9]. Many studies have reported the effects of organic matter content [6,10,11] and organic maturity on shale pore structure [12][13][14][15][16][17]. For example, Wang et al [10] conducted FE-SEM observation, helium porosity measurement, low pressure nitrogen adsorption analyses, high-pressure methane sorption measurements and mechanical tests to investigate the characteristics and dominant controlling factors of Niutitang shales.…”

Section: Introductionmentioning

confidence: 99%

Controls of Distinct Mineral Compositions on Pore Structure in Over-Mature Shales: A Case Study of Lower Cambrian Niutitang Shales in South China

Niu

Yan

et al. 2021

Minerals

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Investigating the impacts of rock composition on pore structure is of great significance to understand shale gas occurrence and gas accumulation mechanism. Shale samples from over-mature Niutitang formation of Lower Cambrian in south China were measured by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), low pressure N2 and CO2 adsorption to elucidate the controls of distinct mineral composition on pore development. Two distinct lithofacies, namely siliceous shale and argillaceous shale, were ascertained based on their mineral composition. Due to the variability of mineral composition in different lithofacies, pore structure characteristics are not uniform. Pores in siliceous shales are dominated by interparticle pores and organic matter (OM) pores, among which the interparticle pores are mainly developed between authigenic quartz. Furthermore, most of these interparticle pores and cleavage-sheet intraparticle pores within clay minerals are usually filled by amorphous organic matter that is host to OM pores. Due to the lack of rigid minerals, argillaceous shale was cemented densely, resulting in few interparticle pores, while cleavage-sheet intraparticle pores within clay minerals are common. Comparing siliceous shales with argillaceous shales, specific surface areas and pore volumes are higher on the former than on the latter. The content of total organic carbon (TOC) and authigenic quartz have a great influence on micropore structures, but less on mesopore structure for siliceous shales. The rigid framework structure formed by authigenic quartz is believed to be able to prevent primary interparticle pores from mechanical compaction and facilitate the formation of organic matter-associated pores. In terms of argillaceous shales, due to the lack of authigenic quartz, interparticle pores were rarely developed and its pore structure is mainly controlled by illite content.

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Section: Introductionmentioning

confidence: 99%

Controls of Distinct Mineral Compositions on Pore Structure in Over-Mature Shales: A Case Study of Lower Cambrian Niutitang Shales in South China

Niu

Yan

et al. 2021

Minerals

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“…Conversely, the progressive conversion of OM, the carbon loss and the significant variations of volume, which occur during oil and gas generation result in the growth of a secondary OM-hosted porosity (Bernard et al, 2012a;Chalmers and Bustin, 2008;Chen and Xiao, 2014;Curtis et al, 2012;Han et al, 2017;Jarvie et al, 2007;Ko et al, 2016Ko et al, , 2018Loucks et al, 2012;Wu et al, 2019). In the vast majority of thermally mature rocks, the OM is the main contributor to the porosity (Bernard et al, 2012a;Cavelan et al, 2019a;Chalmers et al, 2012;Han et al, 2019;Juliao et al, 2015;Katz and Arango, 2018;Ko et al, 2018;Kuila et al, 2014;Loucks et al, 2009Loucks et al, , 2012Milliken et al, 2013;Pan et al, 2015). Thermal maturity and the initial OM composition, which controlled the amount of oil and gas generated during maturation, are thus widely considered as the key factors controlling the formation and the development of pores in organic-rich source rocks (Bernard et al, 2012a(Bernard et al, , 2012bCavelan et al, 2019aCavelan et al, , 2020Chalmers and Bustin, 2008;Chen and Xiao, 2014;Curtis et al, 2012;Ko et al, 2018;Loucks et al, 2009).…”

Section: Introductionmentioning

confidence: 99%

Influence of experimental temperature and duration of laboratory confined thermal maturation experiments on the evolution of the porosity of organic-rich source rocks

Cavelan

Boussafir

Milbeau

et al. 2020

Marine and Petroleum Geology

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“…Rexer et al (2014) proposed an effective OM isolation process that does not alter the pore structure [39]. Therefore, OM isolation from bulk shale provides an effective way to characterize OM pores [39][40][41].…”

Section: Introductionmentioning

confidence: 99%

“…Tian et al (2013) calculated the contribution of OM to pores according to the regression line of TOC content versus porosity [3]. Considering that the pore structure of gas shales may also be controlled by inorganic minerals [13,14,17,31,[46][47][48]50], the accuracy of the results of Loucks et al (2012) and Tian et al (2013) may be low [41].…”

Section: Introductionmentioning

confidence: 99%

Organic Matter Pore Characterization of the Wufeng-Longmaxi Shales from the Fuling Gas Field, Sichuan Basin: Evidence from Organic Matter Isolation and Low-Pressure CO2 and N2 Adsorption

Jiang

et al. 2019

Energies

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Organic matter (OM) pores are significant for shale gas accumulation and flow mechanisms. The pores of Wufeng-Longmaxi (W-L) shale in the Sichuan Basin, China have been extensively characterized, however, the proportion of OM pores in this shale have not been adequately discussed. In this study, the contribution of OM pores to the total pore volume of W-L shale was quantitatively studied through the analysis of OM isolation, field emission scanning electron microscopy (FE-SEM) and low-pressure CO2 and N2 adsorption (LPGA). FE-SEM images showed abundant OM pores, interparticle pores and intraparticle pores with various shapes and widths in the W-L shales. The pore size distribution (PSD) of the isolated OM from five shale samples showed a consistent, unimodal pattern. The pore volume of isolated OM was greater than that of the bulk shale samples, suggesting that OM is more porous than the inorganic compositions in shales. The average contribution of OM to the volumes of micropores, mesopores and macropores was 58.42%, 10.34% and 10.72%, respectively. Therefore, the pore volume of the W-L shale was dominantly related to inorganic minerals. This was probably due to the small weight ratio of OM in the shale samples (1.5 wt%–4.2 wt%). The findings of this study reveal the different effects of OM and minerals on pore development, and provide new insights into the quantitative contribution of OM pores to the total pore volume of the W-L shale.

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Controls of organic and inorganic compositions on pore structure of lacustrine shales of Chang 7 member from Triassic Yanchang Formation in the Ordos Basin, China

Cited by 59 publications

References 44 publications

Controls of Distinct Mineral Compositions on Pore Structure in Over-Mature Shales: A Case Study of Lower Cambrian Niutitang Shales in South China

Controls of Distinct Mineral Compositions on Pore Structure in Over-Mature Shales: A Case Study of Lower Cambrian Niutitang Shales in South China

Influence of experimental temperature and duration of laboratory confined thermal maturation experiments on the evolution of the porosity of organic-rich source rocks

Organic Matter Pore Characterization of the Wufeng-Longmaxi Shales from the Fuling Gas Field, Sichuan Basin: Evidence from Organic Matter Isolation and Low-Pressure CO2 and N2 Adsorption

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