Hydrocarbon Emigration through Microfracturing in Vitrinite: Am Example from the Oligocene Coals of Borjan Coalfield, Nagaland

Borjan coalfield is situated on the western flank of the Naga Hills in the Mon district of Nagaland. Pillar coal samples from Watking and Kongan seams were subjected to detailed petrographic and geochemical investigations for the assessment of their source rock characteristics. During petrographic examination, emigration of exsudatinite (waxy oil) from a microfracture in vitrinite (telocollinite/collotelenite) has been observed. This is a rarely reported visible evidence of primary migration of oil in coal through microfracturing.