Abstract The carbonaceous shale beds of Barren Measures and Barakar Formations of Raniganj basin have been investigated for organic and inorganic content influence on the matrix containing micro, meso, macropores, structures and related fractal dimensions. The significant amount of TOC suggests slow suspension during the consolidation of the sediments in an abundant river channel owing to low energy environmental conditions. The adequate thermal maturity indicates shale beds of both the Formations are good to excellent source rock for dry hydrocarbon genesis. The plot of ln(ln(P/P0)) versus ln(V) have shown three distinct straight line sections within the whole relative pressure range (0.0000–1.0000), further denoted as Region I (P/P0 = 0.0002–0.0090; D1), Region II (P/P0 = 0.0090–0.3000; D2) and Region III (P/P0 = 0.3000–1.0000; D3) and the linear fitting equations were obtained with different slopes. The values of D1, D2, D3, signifying the complexity of micro-, meso- and macropores, providing supplementary sites for gas adsorption. Fractal dimensions have shown a positive correlation with clay content, whereas negative correlation with total organic content indicates that inorganic content plays a vital role in the rugged surface formation useful for gas storage. The positive linear correlation of fractal dimensions (D1 and D2) with Langmuir volume accentuated that smaller pores (micro and meso) contains ideal rugged surfaces suitable for gas adsorption due to heterogeneity, irregular pore surfaces, complex pore openings and structures. Furthermore, D3 shown negligible negative correlation with VL specifies the larger pore size do not provide sites for adsorption space, because of the altered smooth surfaces formed during diagenesis. An empirical method for estimation of sorption capacity (ESC) has been proposed taking into account of the positive and negative influence of the fractal dimensions, clay, minerals and total organic content. The strong positive linear relationship of Langmuir volume (VL) with an empirically estimated sorption capacity (ESC) (R2 = 0.86) and about 90% curves match, signifies the proposed empirical formula can be used as an indirect method for estimation of sorption capacity of shale samples.

中文翻译：

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有机和无机含量对印度Raniganj盆地Barakar和Barren Measures页岩气藏分形维数的影响

摘要 研究了Raniganj 盆地Barren Measures 和Barakar 组碳质页岩层的有机和无机含量对包含微孔、中孔、大孔、结构和相关分形维数的基质的影响。由于低能量环境条件，大量的 TOC 表明在丰富的河道中沉积物固结过程中缓慢悬浮。足够的热成熟度表明这两个地层的页岩层是干烃成因的优良源岩。ln(ln(P/P0)) 与 ln(V) 的曲线在整个相对压力范围 (0.0000–1.0000) 内显示了三个不同的直线部分，进一步表示为区域 I (P/P0 = 0.0002–0.0090; D1)、区域 II（P/P0 = 0.0090–0.3000；D2）和区域 III（P/P0 = 0.3000–1.0000；D3) 和线性拟合方程获得不同的斜率。D1、D2、D3 的值表示微孔、中孔和大孔的复杂性，为气体吸附提供了补充位点。分形维数与粘土含量呈正相关，而与总有机物含量呈负相关表明无机含量在用于储气的崎岖表面地层中起着至关重要的作用。分形维数（D1 和 D2）与朗缪尔体积的正线性相关性强调了较小的孔（微孔和中孔）由于不均匀性、不规则的孔表面、复杂的孔开口和结构而包含适合气体吸附的理想崎岖表面。此外，D3 与 VL 显示出可忽略不计的负相关，表明较大的孔径不提供吸附空间的位点，因为在成岩过程中形成的光滑表面发生了改变。考虑到分形维数、粘土、矿物质和总有机物含量的正面和负面影响，已经提出了一种估算吸附能力 (ESC) 的经验方法。Langmuir 体积 (VL) 与经验估计的吸附容量 (ESC) (R2 = 0.86) 的强正线性关系和约 90% 的曲线匹配，表明所提出的经验公式可用作估计吸附容量的间接方法页岩样品。