Mendhe, V.A. (2017) Geological Controls and Flow Mechanism of Permian Shale Gas Reservoir of Raniganj Basin, West Bengal, India. Journal of Geosciences Research (1). pp. 161-172. ISSN 2455-1953

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Shale gas is an emerging unconventional reservoir after advancement of multilateral-in-bed horizontal drilling and hydrofrac-stimulation technology. Inspiring from US multi fold shale gas production in past decade, India is looking for exploration and development of its shale gas resources. But most of the petroleum industries are under infancy due to lack of fundamental knowledge and technological assistance. With this outlook, the shale core samples obtained from Barakar and Barren Measures Formations during exploratory drilling at Raniganj basin are investigated for shale reservoir insights, geological controls and characteristics. The high pressure CH4and low pressure N2sorption isotherms, rock eval, TOC and in-situ gas content measurements have been carried out. The values of Tmaxof Barakar and Barren Measures varies from 438 to 467°C and 442 to 551°C, TOC varies from 3.38 to 9.99 wt% and 4.86 to 11.72wt%, HI varies from 56 to 108mg and 24 to 181mg HC/g TOC, calculated Ro% determined from rock eval pyrolysis varies from 0.72 to 1.25% and 0.80 to 2.76% and Langmuir volume (VL) varies from 8.16 to 9.30cc/g and 8.37 to 9.44cc/g, respectively. Most of the samples belong to excellent oil to condensate-wet-gas-prone source rock potential at moderate levels of thermal maturity. In-situ gas content of Barakar and Barren Measures varies from 0.42 to 5.82cc/g and 2.90 to 5.14cc/g, respectively. The Barren Measures shales has slightly higher storage capacity than Barakar shales, this may be due to relatively higher organic content. The maximum sorption capacity compared to in-situ gas content reveals that both the shale reservoir (Barakar and Barren Measures) are moderately saturated. The low-pressure N2 adsorption isotherms of both Barakar and Barren Measures shale samples are of type II and IV interpreting the presence of micropores at low pressures, multilayer sorption at moderate pressures and capillary condensation-evaporation at high pressures, which suggests that mesopores to macropores are well developed. The hysteresis loops, formed by the desorption branches are predominantly H3 loop for Barren measures and Barakar shales indicate non-rigid aggregates of plate-like particles giving rise to slit-shaped pores, however, forced closure loop also due to a sudden drop in the volume adsorbed along the desorption branch in P/P0 range 0.41 to 0.48. This phenomenon is often referred to as the tensile strength effect. This study shall help to better understand the shale gas reservoir at Raniganj basin.

Item Type: Article
Uncontrolled Keywords: Shale gas, high-pressure sorption, low-pressure sorption, pore size distribution and in-situ gas content.
Subjects: Methane Emission and Degasification
Depositing User: Mr. B. R. Panduranga
Date Deposited: 04 Aug 2017 09:33
Last Modified: 04 Aug 2017 09:33

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