Studies on thermal maturity and hydrocarbon potential of lignites of Bikaner–Nagaur basin, Rajasthan

Rajak

et al. 2017

Int J Coal Sci Technol

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In the present investigation, Bhavnagar lignites of the Saurashtra basin (Gujarat) have been studied to assess their hydrocarbon generating potential. The samples of upper as well as lower lignite seams have been studied through microscopy and subjected to various chemical analyses viz. proximate analysis, ultimate analysis and Rock-Eval Pyrolysis. These lignites have high moisture and low to moderate ash yield but are characterized by high volatile matter. Petrographically they comprise predominantly of huminite group maceral while liptinite and inertinite groups occur in subordinated amount. Huminite is chiefly composed of detrohuminite and telohuminite. The T max (av. 416.23°C) and huminite reflectivity (0.28%-0.30%) indicate a low degree of maturity for these lignites which is also substantiated by the T max versus hydrogen index plot. The organic matter is subjugated by kerogen Type-III with a potential to expel hydrocarbon on liquefaction. Study further reveals that the fixed hydrocarbon is several folds higher than the free hydrocarbons. Being high in reactive maceral content, a high 'conversion' and good 'oil yield' values for these lignites were observed. Thus, the empirically derived values match well with those obtained through the experimental values of Rock-Eval Pyrolysis and validate their hydrocarbon generating potential.

Section: Maturity Of Lignites Of Saurashtra Basin and Their Hydrocarbmentioning

confidence: 84%

A study on assessment of hydrocarbon potential of the lignite deposits of Saurashtra basin, Gujarat (Western India)

Rajak

et al. 2017

Int J Coal Sci Technol

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Energy Exploration & Exploitation

“…It can be seen from the above formula that in the case of a certain depth of mining, and the maximum vertical principal stress carried by the coal pillar is related to the cohesion and the internal friction angle, which can be determined by the coal physical properties. In the engineering study of UlanQab, the coal type is lignite, which has the high conversion factor and high oil yield (Singh et al, 2016), the metamorphism degree is slight, and the cohesion and internal friction angle increase with the metamorphism degree, which means that the lignite maximum vertical principal stress is the smallest, and the damage is most easily achieved under the same mining width.…”

Section: Ultimate Strength Model and Bearing Mechanism Of Hyperbolic mentioning

confidence: 99%

Stability analysis of hyperbolic coal pillars with peeling and high temperature effects

Guo

et al. 2020

In this present study, a twice-peeling model was established to analyze the hyperbolic coal pillars stability in underground coal gasification and then propose the concept of stripping degree to show model details for numerical simulation. The data shows that hyperbolic coal pillars stability can be analyzed through the twice-peeling model. Considering the coal pillars peeling and high temperature effects, one side of coal pillars will decrease 3 m, and the stability coefficient is 1.6 which has enough bearing capacity. When the arch depth ratio is 0.6, the critical condition for the coal pillar instability is reached. In this paper, underground coal gasification industrial test area still had strong bearing capacity after twice stripping, and there was no sudden instability. The research results can provide reference for the gasifier design and the stability of non-uniform coal pillars in the future.

“…The generated hydrocarbon products have a finite storage capacity and until this capacity is exceeded, no oil expulsion takes place (Powell 1978;Mc Auliffe 1979;Durand 1983;Tissot and Welte 1984;Inan et al 1998). Singh (2012) and Singh et al (2016) have studied the hydrocarbon potential of lignites of Cambay basin and Bikaner basin (India) respectively while investigated the sub-bituminous coals of east Kalimantan (Indonesia) for its liquid hydrocarbon potential. The cross plot of hydrogen index (HI) with oxygen index (OI) and T max of Kasnau-Matasukh lignite (Fig.…”

Section: Hydrocarbon Potentialmentioning

confidence: 99%

“…8) also indicates that these lignites are mainly gas prone. The details of the maturity and oil generating potential of the lignites of entire Bikaner-Nagaur basin have been discussed in detail by Singh et al (2016).…”

Section: Hydrocarbon Potentialmentioning

confidence: 99%

Geochemistry of Kasnau-Matasukh lignites, Nagaur Basin, Rajasthan (India)

Rajak

et al. 2016

Int J Coal Sci Technol

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The distribution and verticals variation of geochemical components in the Kasnau-Matasukh lignites of Nagaur Basin, Rajasthan, were investigated using microscopy, proximate and ultimate analyses, Rock-Eval Pyrolysis, X-ray diffraction and Fourier Transform Infrared analyses, and major/minor/trace element determination. The relationship of elements with ash content and with macerals have also been discussed. These lignites are stratified, black, dominantly composed of huminite group macerals with subordinated amounts of liptinite and inertinite groups. They are classified as type-III kerogen and are mainly gas prone in nature. The concentration (in vol%) of mineral matter is seen to increase towards upper part of seam and so is the concentration (in wt%) of the volatile matter, elemental carbon and sulphur. The common minerals present in these lignitesare mixed clay layer, chlorite, and quartz as identified by X-ray diffraction study. Compared with world average in brown coal, the bulk concentration of Cu is anomalously high in most of the samples while Cd is 2-3 times high and Zn is high in one band. Based on interrelationship, different pyrite forms are noticed to have different preferential enrichment of various elements. The concentration of disseminated pyrite is more than the other pyrite forms and is followed by discrete pyrite grains and massive pyrite.