Mendhe, V.A. and Sharma, Sadanand (2018) Influence of organic and inorganic content on fractal dimensions of Barakar and Barren Measures shale gas reservoirs of Raniganj basin, India. Journal of Natural Gas Science and Engineering, 49. pp. 393-409. ISSN 1875-5100

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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 (D1and 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.

Item Type:	Article
Uncontrolled Keywords:	Shale gas; Fractal dimensions; Organic; Inorganic; Influence; Sorption
Subjects:	Methane Emission and Degasification
Divisions:	UNSPECIFIED
Depositing User:	Mr. B. R. Panduranga
Date Deposited:	27 Dec 2017 04:38
Last Modified:	16 Feb 2018 04:22
URI:	http://cimfr.csircentral.net/id/eprint/1875

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